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Unternehmen, die schnell auf veränderte Marktsituationen reagieren müssen, benötigen eine funktionierende Logistik, die eine Klammerfunktion für alle betrieblichen Bereiche ausübt. Kernstück eines Logistikkonzepts ist das PPS-System, das sich mit Hilfe zeitgemäßer Software immer mehr zur maßgeschneiderten Lösung entwickelt. Ein Weg, um Logistikmodule anforderungsgerecht einzuführen, lässt sich anhand eines besonderen Cim-Modells verdeutlichen, dessen letzter Arbeitsschritt das Auswählen von Hardware und Software ist.
Ausfall- und Ausfallfolgekosten sowie Wiederanlauf- und Zusatzlaufkosten zwingen auch nach betriebswirtschaftlichen Gesichtspunkten die Unternehmen, die Bedeutung und den Umfang der Instandhaltungsaktivitäten höher als bisher einzuschätzen. Der Artikel befasst sich mit der Fragen, warum die Wartung mit in das Logistik-Konzept aufgenommen werden soll.
The use of vibrational sum-frequency spectroscopy (VSFS) to study transferred graphene, produced by chemical vapour deposition, is presented. The VSF spectrum shows a clear CeH stretching mode at ~2924 cm⁻¹, which is attributed to residue of the polymer used for the transfer. This makes VSFS a powerful tool to identify adsorbates and contaminants affecting the properties of graphene.
Die Schaffung eines marktorientierten Lieferspektrums für eine optimale Marktversorgung stellt erhöhte Anforderungen an die Planung und Steuerung des Auftragsabwicklungsprozesses. Über ein betriebsspezifisch entwickeltes Logistikkonzept mit einer anforderungsgerechten CIM-Werkzeuganwahl lassen sich die vorhandenen Probleme, ein volles Fertigwarenlager mit nicht nachgefragten Fertigartikeln, lösen.
We report velocity-dependent internal energy distributions of nitric oxide molecules, NO, scattered off graphene supported on gold to further explore the dynamics of the collision process between NO radicals and graphene. These experiments were performed by directing a molecular beam of NO onto graphene in a surface-velocity map imaging setup, which allowed us to record internal energy distributions of the NO radicals as a function of their velocity. We do not observe bond formation but (1) major contributions from direct inelastic scattering and (2) a smaller trapping–desorption component where some physisorbed NO molecules have residence times on the order of microseconds. This is in agreement with our classical molecular dynamics simulations which also observe a small proportion of two- and multi-bounce collisions events but likewise a small proportion of NO radicals trapped at the surface for the entire length of the molecular dynamics simulations (a few picoseconds). Despite a collision energy of 0.31 eV, which would be sufficient to populate NO(v = 1), we do not detect vibrationally excited nitric oxide.
Worldwide, seagrass meadows are under threat. Consequently, there is a strong need for seagrass restoration to guarantee the provision of related ecosystem services such as nutrient cycling, carbon sequestration and habitat provision. Seagrass often grows in vast meadows in which the presence of seagrass itself leads to a reduction of hydrodynamic energy. By modifying the environment, seagrass thus serves as foundation species and ecosystem engineer improving habitat quality for itself and other species as well as positively affecting its own fitness. On the downside, this positive feedback mechanism can render natural recovery of vanished and destroyed seagrass meadows impossible. An innovative approach to promote positive feedback mechanisms in seagrass restoration is to create an artificial seagrass (ASG) that mimics the facilitation function of natural seagrass. ASG could provide a window of opportunity with respect to suitable hydrodynamic and light conditions as well as sediment stabilization to allow natural seagrass to re-establish. Here, we give an overview of challenges and open questions for the application of ASG to promote seagrass restoration based on experimental studies and restoration trials and we propose a general approach for the design of an ASG produced from biodegradable materials. Considering positive feedback mechanisms is crucial to support restoration attempts. ASG provides promising benefits when habitat conditions are too harsh for seagrass meadows to re-establish themselves.
Die Einführung von EDV-Systemen zur Steuerung und Überwachung des Produktionsprozesses, also in erster Linie PPS (Produktions-Planungs- und -Steuerungs-Systeme) und BDE (Betriebsdatenerfassungs-Systeme) ist im allgemeinen mit einem grossen Arbeits- und Kostenaufwand verbunden, wobei die Effizienz der implementierten Systeme häufig nicht den Erwartungen der Nutzer entspricht. Dies trifft besonders auf die Klein- und Mittelbetriebe zu, weil dort innerhalb der Betriebsorganisation keine Planstellen für EDV-Spezialisten vorgesehen sind, die bei der Umstellung auf eine EDV-Organisation helfen könnten. Diese Stellen liessen sich mit der alleinigen Erledigung von betrieblichen EDV-Aufgaben bei dieser Betriebsgrösse auch nicht wirtschaftlich rechnen. Es muss also vor einer solchen Einführung bereits klar sein, wie aus betriebsorganisatorischer Sicht die EDV mit den vorhandenen Mitarbeitern in den Betriebsprozess einzugliedern ist.
We have combined the velocity map imaging technique with time-of-flight measurements to study the surface photochemistry of KBr single crystals. This approach yields 3-dimensional velocity distributions of Br atoms resulting from 193 nm photodesorption. The velocity distributions indicate that at least two non-thermal mechanisms contribute to the photodesorption dynamics. Our experimental geometry also allows us to measure the Br(²P₃⁄₂):Br(²P₁⁄₂) branching ratio, which is found to be 24:1.
The effects of surface temperature on the gas-liquid interfacial reaction dynamics of O(³P)+squalane
(2005)
OH/OD product state distributions arising from the reaction of gas-phase O(³P) atoms at the surface of the liquid hydrocarbon squalane C₃₀H₆₂/C₃₀D₆₂ have been measured. The O(³P) atoms were generated by 355 nm laser photolysis of NO₂ at a low pressure above the continually refreshed liquid. It has been shown unambiguously that the hydroxyl radicals detected by laser-induced fluorescence originate from the squalane surface. The gas-phase OH/OD rotational populations are found to be partially sensitive to the liquid temperature, but do not adapt to it completely. In addition, rotational temperatures for OH/OD(v′=1) are consistently colder (by 34±5 K) than those for OH/OD(v′=0). This is reminiscent of, but less pronounced than, a similar effect in the well-studied homogeneous gas-phase reaction of O(³P) with smaller hydrocarbons. We conclude that the rotational distributions are composed of two different components. One originates from a direct abstraction mechanism with product characteristics similar to those in the gas phase. The other is a trapping-desorption process yielding a thermal, Boltzmann-like distribution close to the surface temperature. This conclusion is consistent with that reached previously from independent measurements of OH product velocity distributions in complementary molecular-beam scattering experiments. It is further supported by the temporal profiles of OH/OD laser-induced fluorescence signals as a function of distance from the surface observed in the current experiments. The vibrational branching ratios for (v′=1)/(v′=0) for OH and OD have been found to be (0.07±0.02) and (0.30±0.10), respectively. The detection of vibrationally excited hydroxyl radicals suggests that secondary and/or tertiary hydrogen atoms may be accessible to the attacking oxygen atoms.
Background: The topographical correlations between certain extracranial and intracranial osseous points of interest (POIs), and their age-related changes, are indispensable to know for a diagnostical or surgical access to intracranial structures; however, they are difficult to assess with conventional devices.
Materials and methods: In this pilot study, the 3-dimensional coordinates of extra-/intracranial POIs were determined, thus avoiding perspective distortions that used to be intrinsic problems in 2-dimensional morphometry. The data sets were then analysed by creating virtual triangles. The sizes, shapes, and positions of these triangles described the extent and the directions of the age-related shifts of the POIs. A selection of extracranial and intracranial POIs were marked on half skulls of four warmblood horses in two age groups (young: 6 weeks, n = 2; old: 14 and 17 years, n = 2). The x-, y-, and z-coordinates of these POIs were determined with a measurement arm (FaroArm Fusion, FARO Europe®). Direct distances between the POIs as well as their indirect distances on the x-, y-, and z-axis, and angles were calculated.
Results: The analysed virtual triangles revealed that some parts of the skull grew in size, but did not change in shape/relative proportions (proportional type of growth, as displayed by POI A and POI B at the Arcus zygomaticus). The same POIs (A and B) remained in a very stable relationship to their closest intracranial POI at the Basis cranii on the longitudinal axis, however, shifted markedly in the dorso-lateral direction. In contrast, a disproportional growth of other parts of the cranium was, for example, related to POI C at the Crista nuchae, which shifted strongly in the caudal direction with age. A topographically stable reference point (so-called anchor point) at the Basis cranii was difficult to determine.
Conclusions: Two candidates (one at the Synchondrosis intersphenoidalis, another one at the Synchondrosis sphenooccipitalis) were relatively stable in their positions. However, the epicentre of (neuro-)cranial growth could only be pinpointed to an area between them.
Die Marktentwicklung zu kleineren Losgrößen mit zunehmender Variantenvielfalt stellt gerade an einen Programmfertiger erhebliche Anfordungen, um immer das richtige Lieferspektrum in seinem Fertigwarenlager bereitzuhalten. Die einfachste Möglichkeit, dieses Problem zu lösen, besteht in einer hochflexiblen Produktion, bei der die nachgefragten Artikel in der Kundenausführung sofort nach Auftragseingang gefertigt werden. In der Praxis entstehen aber erhebliche Rückstände, weil keine unbegrenzte Kapazität zur Erledigung dieses Aufgabenberges vorhanden wäre.
Am 12. und 13. Juni 1986 fand in Konstanz das Symposium Haftung von Verbundwerkstoffen und Werkstoffverbunden statt. Die Veranstaltung wird in vierjährigem Turnus von der Deutschen Gesellschaft für Metallkunde (DGM) in Zusammenarbeit mit dem Fraunhofer-Institut für angewandte Materialforschung (IFAM) in Bremen ausgerichtet. Als interdisziplinäres Thema stand die Haftung zwischen unterschiedlichen Stoffen auf dem Programm. In 18 Referaten sind Erkenntnisse und Probleme aus unterschiedlichen Arbeitsbereichen vorgetragen worden. Insgesamt nahmen etwas 100 Fachleute aus dem In- und Ausland teil.
The authors describe the application of a combination of velocity map imaging and time-of-flight (TOF) techniques to obtain three-dimensional velocity distributions for surface photodesorption. They have established a systematic alignment procedure to achieve correct and reproducible experimental conditions. It includes four steps: (1) optimization of the velocity map imaging ion optics’ voltages to achieve optimum velocity map imaging conditions; (2) alignment of the surface normal with the symmetry axis (ion flight axis) of the ion optics; (3) determination of TOF distance between the surface and the ionizing laser beam; (4) alignment of the position of the ionizing laser beam with respect to the ion optics. They applied this set of alignment procedures and then measured Br(²P₃/₂) (Br) and Br(²P₁/₂) (Br∗) atoms photodesorbing from a single crystal of KBr after exposure to 193 nm light. They analyzed the velocity flux and energy flux distributions for motion normal to the surface. The Br∗ normal energy distribution shows two clearly resolved peaks at approximately 0.017 and 0.39 eV, respectively. The former is slightly faster than expected for thermal desorption at the surface temperature and the latter is hyperthermal. The Br normal energy distribution shows a single broad peak that is likely composed of two hyperthermal components. The capability that surface three-dimensional velocity map imaging provides for measuring state-specific velocity distributions in all three dimensions separately and simultaneously for the products of surface photodesorption or surface reactions holds great promise to contribute to our understanding of these processes.
Surface atomic relaxation and magnetism on hydrogen-adsorbed Fe(110) surfaces from first principles
(2016)
We have computed adsorption energies, vibrational frequencies, surface relaxation and buckling for hydrogen adsorbed on a body-centred-cubic Fe(110) surface as a function of the degree of H coverage. This adsorption system is important in a variety of technological processes such as the hydrogen embrittlement in ferritic steels, which motivated this work, and the Haber–Bosch process. We employed spin-polarised density functional theory to optimise geometries of a six-layer Fe slab, followed by frozen mode finite displacement phonon calculations to compute Fe–H vibrational frequencies. We have found that the quasi-threefold (3f) site is the most stable adsorption site, with adsorption energies of ∼3.0 eV/H for all coverages studied. The long-bridge (lb) site, which is close in energy to the 3f site, is actually a transition state leading to the stable 3f site. The calculated harmonic vibrational frequencies collectively span from 730 to 1220 cm−1, for a range of coverages. The increased first-to-second layer spacing in the presence of adsorbed hydrogen, and the pronounced buckling observed in the Fe surface layer, may facilitate the diffusion of hydrogen atoms into the bulk, and therefore impact the early stages of hydrogen embrittlement in steels.
The ability to functionalize graphene with several methods, such as radical reactions, cycloadditions, hydrogenation, and oxidations, allows this material to be used in a large range of applications. In this framework, it is essential to be able to control the efficiency and stability of the functionalization process—this requires understanding how the graphene reactivity is affected by the environment, including the substrate. In this work we provide an insight on the substrate dependence of graphene reactivity towards hydrogenation by comparing three different substrates: silicon, hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2). Although MoS2 and h-BN have flatter surfaces than silicon, we found that the H coverage of graphene on h-BN is about half of the H coverage on graphene on both silicon and MoS2. Therefore, graphene shows strongly reduced reactivity towards hydrogenation when placed on h-BN. The difference in hydrogenation reactivity between h-BN and MoS2 may indicate a stronger van der Waals force between graphene and h-BN, compared to MoS2, or may be related to the chemical properties of MoS2, which is a well-known catalyst for hydrogen evolution reactions.
Die Analyse von Struktureffekten in der „Allgemeine Milchbehandlung“ wird anhand zweier Fragen vorgenommen:
1. Welche Effekte hat die Größe der Abteilung auf die Produktionskosten?
2. Welche Kosteneinsparungen hätten - ausgehend von der bundesdeutschen Ist-Struktur milchverarbeitender Betriebsstätten - moderate Strukturveränderungen zur
Folge?
Struktureffekte bei der Schnittkäseproduktion. Thesen und Argumente zur Molkereistruktur Teil III
(1990)
Im Rahmen dieses Beitrages wird die Wechselwirkung zwischen abteilungsspezifischen Produktionskosten und der Struktur von Produktionsabteilungen für die Herstellung von Schnittkäse untersucht. Die Analyse eventueller Struktureffekte geschieht in zwei Schritten: zuerst wird der Einfluß unterschiedlicher Kapazitätsgrößen und -auslastungen von Käsereiabteilungen auf die Produktionskosten bestimmt. Danach wird der Frage nachgegangen, wie die Produktionsstrukturen für Schnittkäse in der BR Deutschland aussehen und welche Kosteneinsparungspotentiale sich bei moderaten Strukturveränderungen ergeben.
A proven method to enhance the mechanical properties of additively manufactured plastic parts is the embedding of continuous fibers. Due to its great flexibility, continuous fiber-reinforced material extrusion allows fiber strands to be deposited along optimized paths. Nevertheless, the fibers have so far been embedded in the parts contour-based or on the basis of regular patterns. The outstanding strength and stiffness properties of the fibers in the longitudinal direction cannot be optimally utilized. Therefore, a method is proposed which allows to embed fibers along the principal stresses into the parts in a load-oriented manner. A G-code is generated from the calculated principal stress trajectories and the part geometry, which also takes into account the specific restrictions of the manufacturing technology used. A distinction is made between fiber paths and the matrix so that the average fiber volume content can be set in a defined way. To determine the mechanical properties, tensile and flexural tests are carried out on specimens consisting of carbon fiber-reinforced polyamide. In order to increase the influence of the principal stress-based fiber orientation, open-hole plates are used for the tensile tests, as this leads to variable stresses across the cross section. In addition, a digital image correlation system is used to determine the deformations during the mechanical tests. It was found that the peak load of the optimized open-hole plates was greater by a factor of 3 and the optimized flexural specimens by a factor of 1.9 than the comparison specimens with unidirectional fiber alignment.
Streptococcus dysgalactiae is among the most important pathogens causing bovine mastitis. Unfortunately, there is presently a lack of clear knowledge about the mode of transmission — contagious or environmental — of this pathogen. To obtain more information on this, knowledge of the genetic diversity of the isolated microorganisms at the farm level can be useful. To observe the strain variety in different herds of cattle, isolates of Strep. dysgalactiae were collected from clinical mastitis samples at different farms, and the strains were typed using the pulsed-field gel electrophoresis (PFGE) method. Overall, we performed strain typing on 93 isolates from 16 farms in Germany and used an index to describe the degree of contagiosity of Strep. dysgalactiae at each farm. This index (CI) represents the number of isolates divided by the number of strains found in mastitis milk of clinical cases within a period of 14 months. The results differed between the farms. In one farm, all six Strep. dysgalactiae cases that occurred during the study period were caused by a single strain (CI = 6), while in another farm the six cases that occurred were caused by five different strains (CI = 1.2). All other farms fell between these two extremes. This indicates that Strep. dysgalactiae infections can occur via several routes of transmission. At the farm level, strain comparisons are necessary to determine the routes of transmission. Two strains were able to survive on the farm for a minimum of 14 months.
To effectively prevent and control bovine mastitis, farmers and their advisors need to take infection pathways and durations into account. Still, studies exploring both aspects through molecular epidemiology with sampling of entire dairy cow herds over longer periods are scarce. Therefore, quarter foremilk samples were collected at 14-d intervals from all lactating dairy cows (n = 263) over 18 wk in one commercial dairy herd. Quarters were considered infected with Staphylococcus aureus, Streptococcus uberis, or Streptococcus dysgalactiae when ≥100 cfu/mL of the respective pathogen was detected, or with Staphylococcus epidermidis or Staphylococcus haemolyticus when ≥500 cfu/mL of the respective pathogen was detected. All isolates of the mentioned species underwent randomly amplified polymorphic DNA (RAPD)-PCR to explore strain diversity and to distinguish ongoing from new infections. Survival analysis was used to estimate infection durations. Five different strains of Staph. aureus were isolated, and the most prevalent strain caused more than 80% of all Staph. aureus infections (n = 46). In contrast, 46 Staph. epidermidis and 69 Staph. haemolyticus strains were isolated, and none of these caused infections in more than 2 different quarters. The 3 most dominant strains of Strep. dysgalactiae (7 strains) and Strep. uberis (18 strains) caused 81% of 33 and 49% of 37 infections in total, respectively. The estimated median infection duration for Staph. aureus was 80 d, and that for Staph. epidermidis and Staph. haemolyticus was 28 and 22 d, respectively. The probability of remaining infected with Strep. dysgalactiae or Strep. uberis for more than 84 and 70 d was 58.7 and 53.5%, respectively. Staphylococcus epidermidis and Staph. haemolyticus were not transmitted contagiously and the average infection durations were short, which brings into question whether antimicrobial treatment of intramammary infections with these organisms is justified. In contrast, infections with the other 3 pathogens lasted longer and largely originated from contagious transmission.
Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.
The aim of this cross-sectional study was to investigate associated factors of the severity of clinical mastitis (CM). Milk samples of 249 cases of CM were microbiologically examined, of which 27.2% were mild, 38.5% moderate, and 34.3% severe mastitis. The samples were incubated aerobically and anaerobically to investigate the role of aerobic and anaerobic microorganisms. In addition, the pathogen shedding was quantitatively examined, and animal individual data, outside temperature and relative humidity, were collected to determine associated factors for the severity of CM. The pathogen isolated the most was Escherichia coli (35.2%), followed by Streptococcus spp. (16.4%). Non-aureus staphylococci (NaS) (15.4%) and other pathogens (e.g., Staphylococcus aureus, coryneforms) (15.4%) were the pathogens that were isolated the most for mild mastitis. Moderate mastitis was mostly caused by E. coli (38%). E. coli was also the most common pathogen in severe mastitis (50.6%), followed by Streptococcus spp. (16.4%), and Klebsiella spp. (10.3%). Obligate anaerobes (Clostridium spp.) were isolated in one case (0.4%) of moderate mastitis. The mortality rate (deceased or culled due to the mastitis in the following two weeks) was 34.5% for severe mastitis, 21.7% for moderate mastitis, and 4.4% for mild mastitis. The overall mortality rate of CM was 21.1%. The pathogen shedding (back logarithmized) was highest for severe mastitis (55,000 cfu/mL) and E. coli (91,200 cfu/mL). High pathogen shedding, low previous somatic cell count (SCC) before mastitis, high outside temperature, and high humidity were associated with severe courses of mastitis.
Der Zugscherversuch ist die am häufigsten angewandte Prüftechnik für Klebverbindungen. Die dabei ermittelte Klebfestigkeit ist jedoch eine wenig aussagefähige Größe. In keinem Fall kann sie als Werkstoffkennwert den Klebstoff charakterisieren. Als Ausgangsgröße für Berechnungen bei der Dimensionierung von Klebverbindungen ist das Ergebnis des Zugscherversuchs deshalb nicht geeignet.
In this paper a new rotor position observer for permanent magnet synchronous machines (PMSM) based on an Extended-Kalman-Filter (EKF) is presented. With this method, just one single EKF is sufficent to evaluate the position information from electromotive force (EMF) and anisotropy. Thus, the PMSM can be controlled for the entire speed range without a position sensor and without the need to switch or synchronize between different observers. The approach covers online estimation of permanent magnetic field and mechanical load. The resulting EKF-based rotor position estimator is embedded in the existing cascaded control concept of the PMSM without need of additional angle trackers or signal filters. The experimental validation for the position sensorless control shows optimized dynamic behaviour.
Innerhalb der vereinfachten Logistikformel "Das richtige Material in richtiger Höhe und richtiger Qualität zum richtigen Zeitpunkt am richtigen Platz zur Verfügung zu stellen" spielt die Festlegung des richtigen Zeitpunktes bei der Durchsetzung der logistischen Zielsetzung eine besonders wichtige Rolle. Es ist damit der Bedarfszeitpunkt gemeint, diesen exakt zu bestimmen und dann im Ablauf auch einzuhalten, bereitet häufig große Schwierigkeiten. Dieser Bedarfszeitpunkt legt den genauen Termin im zeitlichen Prozessablauf innerhalb der gesamten betrieblichen Vorsorgungskette fest, an dem die benötigten Materialien und Produktionsmittel zur Verfügung stehen müssen. Seine Bedeutung erhält der Bedarfzeitpunkt dadurch, dass Interessen oder Zielsetzungen der Beschaffungs-, Produktions- und Vertriebslogistik hier zusammentreffen.
To design cost-effective prevention strategies against mastitis in dairy cow farms, knowledge about infection pathways of causative pathogens is necessary. Therefore, we investigated the reservoirs of bacterial strains causing intramammary infections in one dairy cow herd. Quarter foremilk samples (n = 8056) and milking- and housing-related samples (n = 251; from drinking troughs, bedding material, walking areas, cow brushes, fly traps, milking liners, and milker gloves), were collected and examined using culture-based methods. Species were identified with MALDI-TOF MS, and selected Staphylococcus and Streptococcus spp. typed with randomly amplified polymorphic DNA-PCR. Staphylococci were isolated from all and streptococci from most investigated locations. However, only for Staphylococcus aureus, matching strain types (n = 2) were isolated from milk and milking-related samples (milking liners and milker gloves). Staphylococcus epidermidis and Staphylococcus haemolyticus showed a large genetic diversity without any matches of strain types from milk and other samples. Streptococcus uberis was the only Streptococcus spp. isolated from milk and milking- or housing-related samples. However, no matching strains were found. This study underlines the importance of measures preventing the spread of Staphylococcus aureus between quarters during milking.
Although Corynebacterium spp. can be regularly associated with subclinical and clinical mastitis cases in dairy cows, knowledge on their reservoirs in dairy farms is sparse. Therefore, samples were collected at 10 visits with 14 day intervals from bedding material (n = 50), drinking troughs (n = 20), different walking areas (n = 60), cow brushes (n = 8), fly traps (n = 4), the passage to pasture (n = 9) as well as milking liners (n = 80) and milker gloves (n = 20) in one dairy cow farm. Additionally, quarter foremilk samples from all lactating cows (approximately 200) were collected at each visit. All samples underwent microbiological examination and cultured isolates were identified using MALDI-TOF MS. Most Corynebacterium spp. that were cultivated from milk were also isolated from the housing environment and milking-related niches (C. amycolatum, C. confusum, C. stationis, C. variabile, C. xerosis) or from milking-related niches only (C. frankenforstense, C. pilosum, C. suicordis). C. bovis was not cultivated from any environmental niche, while being the dominant species in milk samples. This study demonstrates that many Corynebacterium spp. present in milk samples can also be isolated from the cows’ environment. For C. bovis, the most relevant Corynebacterium species with regard to intramammary infections, it indicates that environmental reservoirs are of little relevance.
Bei Qualitätsmängeln ist es mit der reihenfolgegerechten und zeitgenauen Anlieferung direkt in den Produktionsbereich nicht mehr möglich, auf Ersatzmaterial zurückzugreifen. Ein wichtiger Schritt zu der daher geforderten Null-Fehler-Rate in der Produktion ist die informationstechnische Einbindung der Qualitätssicherung in das Logistik-Konzept des Unternehmens. der Artikel beschreibt, wie eine solche Einbindung aussieht.
Nach wie vor ist die seit langem bekannte Forderung nach einer durchgängigen Transparenz des betrieblichen Werteflusses zur Überprüfung der vorgegebenen logistischen Zielvereibarungen und als Hilfe zur Entscheidungsfindung über ein funktionierendes Produktions-Controlling nur sehr schwierig zu erfüllen. Hier hilft der Einsatz von anforderungsgerecht eingeführten BDE-Systemen und die exakte Definition der Zielgrößen in Form von Kennzahlen.
Die Prüfung von Klebverbindungen erfolgt häufig im Zugscherversuch. Bei der Anwendung dieser Prüfmethode bei Polymer-Metall-Klebverbindungen tritt oft ein Bruch im Polymerteil auf. Dadurch wird die Aussagefähigkeit des Zugscherversuchs stark eingeschränkt. Das gilt vor allem für die Optimierung der Oberflächenvorbehandlung von Polymerteilen. Der vorliegende Beitrag untersucht die Beanspruchungsparameter von Polymer-Metall-klebverbindungen im Zugscherversuch und leitet daraus Forderungen an geeignete Prüfanordnungen ab.
The aim of the current study was to investigate the effects of the prepartum external treatment of teats with a combination of four lactic acid bacteria strains viz. Lactobacillus (Lb.) rhamnosus ATCC 7469, Lactococcus lactis subsp. lactis ATCC 11454, Lb. paracasei 78/37 (DSM 26911), and Lb. plantarum 118/37 (DSM 26912) on the postcalving udder health of dairy heifers. The study used a split-udder design. Two weeks before the expected calving date, one of two contralateral teats of a teat pair was dipped with an aqueous suspension of lactic acid bacteria (final bacterial counts 8.40–8.47 log10-transformed CFU/mL) once in a week until calving; the other teat of the pair was not treated. After calving, quarter foremilk samples were taken and investigated cyto-microbiologically. In total, 629 teat pairs of 319 heifers were included. There was an association between the treatment and intramammary infections caused by the major udder-pathogenic bacteria Staphylococcus aureus, Streptococcus dysgalactiae, and enterococci, as well as clinical mastitis in the first 100 days after calving. The present study indicates that intramammary infections with major pathogens and clinical mastitis may be prevented by regular prepartum external application of lactic acid bacteria in dairy heifers.
Electrospinning with consequent thermal treatment consists in a carbon fiber production method that spins a polymer solution to create fibers with diameters around a few hundred nanometers. The thermal treatments are used for the cyclization and then carbonization of the material at 1700 °C for one hour. The unique structure of micro- and nano-carbon fibers makes them a promising material for various applications ranging from future battery designs to filtration. This work investigated the possibility of using milled gasification biochar, derived from a 20 kW fixed-bed gasifier fueled with vine pruning pellets, as an addictive in the preparation of electrospinning solutions. This study outlined that solvent cleaning and the consequent wet-milling and 32 µm sifting are fundamental passages for biochar preparation. Four different polyacrylonitrile-biochar shares were tested ranging from pure polymer to 50–50% solutions. The resulting fibers were analyzed via scanning electron microscopy, and energy-dispersive X-ray and infrared spectroscopy. Results from the morphological analysis showed that biochar grains dispersed themselves well among the fiber mat in all the proposed shares. All the tested solutions, once carbonized, exceeded 97%wt. of carbon content. At higher carbonization temperatures, the inorganic compounds naturally showing in biochar such as potassium and calcium disappeared, resulting in an almost carbon-pure fiber matrix with biochar grains in between.
PPS-Anbieter herausfordern
(2008)
Wer die Einführung eines PPS- oder Logistik-Systems plant, sollte mit einer exakten Beschreibung der Soll-Abläufe die Anbieter auffordern, konkret Stellung zu beziehen, was ihr System kann und nicht kann. Der Artikel beschreibt, wie ein solches Anforderungsprofil aussehen soll, wie man es aufbaut und wie man bei der Einführung eines PPS-Systems vorgeht.
Parametric study of piezoresistive structures in continuous fiber reinforced additive manufacturing
(2024)
Recent advancements in fiber reinforced additive manufacturing leverage the piezoresistivity of continuous carbon fibers. This effect enables the fabrication of structural components with inherent piezoresistive properties suitable for load measurement or structural monitoring. These are achieved without necessitating additional manufacturing or assembly procedures. However, there remain unexplored variables within the domain of continuous fiber-reinforced additive manufacturing. Crucially, the roles of fiber curvature radii and sensing fiber bundle counts have yet to be comprehensively addressed. Additionally, the compression-sensitive nature of printed carbon fiber-reinforced specimens remains a largely unexplored research area. To address these gaps, this study presents experimental analyses on tensile and three-point flexural specimens incorporating sensing carbon fiber strands. All specimens were fabricated with three distinct curvature radii. For the tensile specimens, the number of layers was also varied. Sensing fiber bundles were embedded on both tensile and compression sides of the flexural specimens. Mechanical testing revealed a linear-elastic behavior in the specimens. It was observed that carbon fibers supported the majority of the load, leading to brittle fractures. The resistance measurements showed a dependence on both the number of sensing layers and the radius of curvature, and exhibited a slight decreasing trend in the cyclic tests. Compared with the sensors subjected to tensile stress, the sensors embedded on the compression side showed a lower gauge factor.
A nonblinded, positively controlled, noninferiority trial was conducted to evaluate the efficacy of an alternative, nonantibiotic therapy with Masti Veyxym® to reduce ineffective antibiotic usage in the treatment of nonsevere clinical mastitis (CM) in cows with longer lasting udder diseases. The solely intramammary treatment with Masti Veyxym® (three applications, 12 hr apart) and the combined treatment with Masti Veyxym® and antibiotics as usual on the farm according to label of the respective product were compared with the reference treatment of solely antibiotic therapy. The matched field study was conducted on eight free-stall dairy farms located in Eastern Germany. Cases of mild-to-moderate CM in cows with longer lasting high somatic cell counts in preceding dairy herd improvement test days and with previous CM cases in current lactation were randomly allocated to one of the three treatment groups. A foremilk sample of the affected quarter was taken before treatment and again approximately 14 days and 21 days after the end of therapy for cyto-bacteriological examination. Primary outcomes were clinical cure (CC) and no CM recurrence within 60 days after the end of treatment (no R60). Bacteriological cure (BC) and quarter somatic cell count (QSCC) cure were chosen as secondary outcomes although low probabilities of BC and QSCC cure for selected cows were expected. The study resulted in the following findings: the pathogens mostly cultured from pretreatment samples were Streptococcus uberis, followed by Staphylococcus aureus and coagulase-negative staphylococci. There were no significant differences between the two test treatments in comparison with the reference treatment regarding all outcome variables. The sole therapy with Masti Veyxym® resulted in a numerically lower likelihood of BC without significant differences to the reference treatment. The combined therapy group showed a numerically higher nonrecurrence rate than the two other treatment groups and noninferiority compared to the reference treatment was proven. Having regard to the selection criteria of cows in this study, the findings indicated that sole treatment with Masti Veyxym® in nonsevere CM cases may constitute an alternative therapy to reduce antibiotics. However, noninferiority evaluations were mostly inconclusive. Further investigations with a larger sample size are required to confirm the results and to make a clear statement on noninferiority.
To reduce ineffective antimicrobial usage in the treatment of non-severe clinical mastitis (CM) in cows with long-lasting udder diseases, non-antibiotic therapy with a non-steroidal anti-inflammatory drug (NSAID) was conducted and evaluated in a non-blinded, positively controlled, non-inferiority trial. Therefore, three-time systemic ketoprofen treatment at intervals of 24 h was evaluated in comparison with the reference treatment of solely antibiotic therapy in a field study on nine free-stall dairy farms located in Northern Germany. Cows with previous CM cases in current lactation and/or with long-lasting high somatic cell counts in preceding dairy herd improvement test days were randomly allocated to one of the two treatment groups in cases of mild to moderate CM. Quarter foremilk samples of the affected quarters were taken for cyto-bacteriological investigation before treatment as well as ~14 and 21 d after termination of therapy. Both treatment groups were compared regarding the bacteriological cure (BC) as the primary outcome. Clinical cure (CC) and no CM relapse within 60 d after the end of treatment (no R60) were chosen as secondary outcomes. The study resulted in the following outcomes: Streptococcus uberis was most frequently identified in microbiological culture from pre-treatment samples, followed by Staphylococcus aureus and Escherichia coli and other coliforms. No significant differences between the NSAID treatment and the reference treatment were detected regarding CC and CM recurrence (no R60). Although the sole ketoprofen therapy resulted in a numerically lower likelihood of BC, there were no significant differences to the reference treatment. Considering the selection criteria in this study, the results indicate that in mild to moderate CM cases exclusive treatment with ketoprofen may constitute an alternative to antimicrobial intramammary therapy, providing an opportunity for reduction of antibiotic usage. However, non-inferiority evaluations were inconclusive. Further investigations with a larger sample size are required to confirm the results and to make a distinct statement on non-inferiority.
Energy- and angle-resolved photofragment distributions for ground-state Cl (²P₃/₂) and spin–orbit excited Cl* (²P₁/₂) have been recorded using the velocity map imaging technique after photodissociation of chloroform at wavelengths of 193 and ∼235 nm. Translational energy distributions are rather broad and peak between 0.6 and 1.0 eV. The spin–orbit branching ratios [Cl*]/[Cl] are 1 and 0.3 at 193 and 235 nm, respectively, indicating the involvement of two or more excited state surfaces. Considering the anisotropy parameters and branching ratios collectively, we conclude that the reaction at 193 nm takes place predominantly on the ¹Q₁ surface, while the ³Q₁ surface gains importance at lower dissociation energies around 235 nm.
Nur wenn eine klebgerecht ausgeführte Konstruktion mit dem richtigen Klebstoff nach optimaler Oberflächenbehandlung und mit angepssten Abbindebedingungen gefertigt wird, sind Klebverbindungen von maximaler Festigkeit und Alterungsbeständigkeit zu erzielen. Am Beispiel von Bremsbelägen wird gezeigt, dass bei einer entsprechenden Erprobung auch sogenannte Sicherheitsteile durch Kleben hergestellt werden könne.
Molecular hydrogen production from amorphous solid water during low energy electron irradiation
(2017)
This work investigates the production of molecular hydrogen isotopologues (H2, HD, and D2) during low energy electron irradiation of layered and isotopically labelled thin films of amorphous solid water (ASW) in ultrahigh vacuum. Experimentally, the production of these molecules with both irradiation time and incident electron energy in the range 400 to 500 eV is reported as a function of the depth of a buried D2O layer in an H2O film. H2 is produced consistently in all measurements, reflecting the H2O component of the film, though it does exhibit a modest reduction in intensity at the time corresponding to product escape from the buried D2O layer. In contrast, HD and D2 production exhibit peaks at times corresponding to product escape from the buried D2O layer in the composite film. These features broaden the deeper the HD or D2 is formed due to diffusion. A simple random-walk model is presented that can qualitatively explain the appearance profile of these peaks as a function of the incident electron penetration.
We performed classical molecular dynamics simulations to model the scattering process of nitric oxide, NO, off graphene supported on gold. This is motivated by our desire to probe the energy transfer in collisions with graphene. Since many of these collision systems comprising of graphene and small molecules have been shown to scatter non-reactively, classical molecular dynamics appear to describe such systems sufficiently. We directed thousands of trajectories of NO molecules onto graphene along the surface normal, while varying impact position, but also speed, orientation, and rotational excitation of the nitric oxide, and compare the results with experimental data. While experiment and theory do not match quantitatively, we observe agreement that the relative amount of kineti cenergy lost during the collision increases with increasing initial kinetic energy of the NO. Furthermore, while at higher collision energies, all NO molecules lose some energy, and the vast majority of NO is scattered back, in contrast at low impact energies, the fraction of those nitric oxide molecules that are trapped at the surface increases, and some NO molecules even gain some kinetic energy during the collision process. The collision energy seems to preferentially go into the collective motion of the carbon atoms in the graphene sheet.
Viele Kunststoffe besitzen nur schlechte Adhäsionseigenschaften. So lassen sich viele technisch wichtige Kunststoffe adhäsiv nur dann zufriedenstellend mit Adhäsionsklebstoffen kleben, wenn die Kunststoffteile vorbehandelt worden sind. Versuche mit einer Niederdruckplasmabehandlung führten zu brauchbaren Ergebnissen.
The aim of this study was to examine the opinions of farmers on a consulting project, which was established for organic dairy farms in Northern Germany involving different animal health experts who participated in the meetings. Furthermore, the properties of measures that are of decisive importance for implementation on the farms were identified to improve consultancy services for dairy farming. Once a year, the farmers met on a host-farm in one of three groups consisting of five to nine farms, a facilitator and an expert. At each meeting, a host-farm was visited and the analysed data of all participating farms of the previous year were presented to the group members. Each farmer had the possibility to report on success stories and issues concerning his herd. During discussions, the farmers first proposed mutual farm-specific measures for improving herd health and animal welfare. Afterwards, the expert named possible interventions and commented on the given measures of the farmers. All measures were noted by the facilitator. At the end of each meeting, each farmer could choose which of the given measures he wanted to implement. Open group-interviews as well as anonymous questionnaires for the farmers were used at the meetings in winter 2016/2017 to evaluate their perception of this consulting project and to determine which properties of measures were important for implementation on the farms. Based on the results of this study, the participating farmers were very positive towards this kind of consulting project. They favoured the participation of an expert during the meetings and the analysis of farm-specific data. Farmers mostly chose measures for implementation proposed by farmers and approved by the expert, followed by those proposed by the expert only. Measures were chosen when they were practical in the implementation, effective, efficient and took a low additional workload for implementation.
Die Serie von Modellabteilungsrechnungen wird mit der Untersuchung des Kostenverlaufs in der Abteilung Weichkäse fortgefuhrt, um einen weiteren Baustein zur Bestimmung optimaler Produktionsstrukturen zu erhalten. Als Ausgangsposition dieser Themenstellung soll im folgenden die Modellabteilung Weichkäse Gestalt annehmen. Dazu sind drei Arbeitsschritte notwendig: die Festlegung des zu untersuchenden Produktes, die inhaltliche Abgrenzung der zu bildenden Modellabteilung und die Auswahl des Fertigungsverfahrens.
We present a methodology based on mixed-integer nonlinear model predictive control for a real-time building energy management system in application to a single-family house with a combined heat and power (CHP) unit. The developed strategy successfully deals with the switching behavior of the system components as well as minimum admissible operating time constraints by use of a special switch-cost-aware rounding procedure. The quality of the presented solution is evaluated in comparison to the globally optimal dynamic programming method and conventional rule-based control strategy. Based on a real-world scenario, we show that our approach is more than real-time capable while maintaining high correspondence with the globally optimal solution. We achieve an average optimality gap of 2.5% compared to 20% for a conventional control approach, and are faster and more scalable than a dynamic programming approach.
Mixed-integer NMPC for real-time supervisory energy management control in residential buildings
(2023)
In recent years, building energy supply and distribution systems have become more complex, with an increasing number of energy generators, stores, flows, and possible combinations of operating modes. This poses challenges for supervisory control, especially when balancing the conflicting goals of maximizing comfort while minimizing costs and emissions to contribute to global climate protection objectives. Mixed-integer nonlinear model predictive control is a promising approach for intelligent real-time control that is able to properly address the specific characteristics and restrictions of building energy systems. We present a strategy that utilizes a decomposition approach, combining partial outer convexification with the Switch-Cost Aware Rounding procedure to handle switching behavior and operating time constraints of building components in real-time. The efficacy is demonstrated through practical applications in a single-family home with a combined heat and power unit and in a multi-family apartment complex with 18 residential units. Simulation studies show high correspondence to globally optimal solutions with significant cost savings potential of around 19%.
Mit BDE immer dicht am Ball
(1989)
Wer Logistikabläufe unter Kontrolle halten will, gliedert sie hierzu in Teilabläufe und sorgt dafür, daß am Ende jedes wichtigen Teilablaufs festgestellt wird, ob alles nach Plan läuft oder nicht. Die Computertechnik hält hierfür sogenannte BDE-Terminals bereit, also Eingabestationen für Betriebsdaten. Verbindet man die Stationen mit einem zentralen Computer, kann man den gesamten Ablauf lückenlos überwachen. Der folgende Artikel beschreibt, wie BDE das Erreichen der Logistikziele, kurze Auftragsdurchlaufzeit bei minimalen Beständen und hoher Termintreue, fördert.
Methodische Weiterentwicklungen der Modellabteilungsrechnung für milchwirtschaftliche Betriebe
(1990)
Vor 15 Jahren wurde der erste Beitrag einer Serie von Modellabteilungsrechnungen mit dem Ziel veröffentlicht, der Praxis und Wissenschaft nachvollziehbare Planungshilfen
für die Gestaltung optimaler Produktionsstrukturen in der Milchwirtschaft an die Hand zu geben. Dieses Ziel gilt auch heute noch, jedoch hat sich im Laufe der Zeit immer
deutlicher herauskristallisiert, daß eine Fortschreibung der Faktorpreise sowie eine gelegentliche Aktualisierung der Faktormengenverbräuche in Anpassung an neue technologische Entwicklungen allein nicht ausreichen, die selbstgesetzen Ansprüche an die Modellabteilungsrechnung zu erfüllen.
The velocity distribution of He atoms evaporating from a slab of liquid dodecane has been simulated. The distribution composed of ∼10 000 He trajectories is shifted to fractionally faster velocities as compared to a Maxwell–Boltzmann distribution at the temperature of the liquid dodecane with an average translational energy of 1.05 × 2RT (or 1.08 × 2RT after correction for a cylindrical liquid jet), compared to the experimental work by Nathanson and co-workers (1.14 × 2RT) on liquid jets. Analysis of the trajectories allows us to infer mechanistic information about the modes of evaporation, and their contribution to the overall velocity distribution.
Matrizen ordnen Behälterlauf
(1989)
This feasibility study investigates the flexural properties of biocomposites containing woven flax textiles (plain, twill, satin) and woven twill patterned hybrid textiles containing flax-/glass or flax-/carbon mixture for lightweight applications. Synthetic fibers are integrated as weft and flax fibers are integrated as warp yarns using a double-rapier weaving machine with a Jacquard attachment. The corresponding biocomposites are manufactured via vacuum infusion process using a biobased epoxy resin as a matrix. The manufactured biocomposites are analyzed with regard to their density and flexural properties. The results show that the use of hybrid textiles offers a promising solution for the manufacture of biocomposites with a higher biobased content and significantly improved flexural properties. Furthermore, the introduction of high-performance synthetic fibers in textiles enables the manufacture of biocomposites with an isotropic mechanical performance.
Subclinical mastitis in heifers during early lactation affects udder health, future milk production and, therefore, the risk of premature culling. The aim of this cross-sectional study was to identify pre- and post-partum risk factors associated with a high heifer mastitis rate (HMR), and to find out which period (either pre- or post-partum) contains more risk factors and consequently should be the focus of mastitis control in heifers. A total of 77 herds were included in this study and the potential animal- and farm-related risk factors were recorded during a one-time farm visit. The HMR was provided by the dairy herd improvement test (DHI) as the annual average of the past 11 DHIs. For this study, data were analyzed in two models using generalized linear models. Each model examined the association between possible risk factors and HMR, one including only prepartum risk factors and the other one only post-partum risk factors. One identified pre-partum risk factor was the proportion of udder-healthy cows in the herd. Post-partum risk factors were the type of teat cleaning procedure before milking, teat disinfection, treatment of mastitis in heifers, a body condition score (BCS) of >3.0 in fresh heifers, and the combination of a teat cleaning procedure with a teat disinfectant. The results show the importance of the period shortly after calving for udder health in heifers, as four of the five significant risk factors were identified in this period and three of them were related to the milking process. However, further research with a higher number of herds is needed to minimize individual herd effects.
In a cross-sectional study, impact of management in dairy farms on calf mortality rates and prevalence of rotavirus and Cryptosporidium parvum in feces of calves was investigated. Sixty-two commercial dairy herds in Mecklenburg-Western Pomerania, Germany, were stratified selected in 2019. We performed in-person interviews and fecal specimens in samples of all-female calves of age 7 up to 21 days. Management data were documented on farm level. A Multiscreen Ag-ELISA was performed to determine rotavirus and Cryptosporidium parvum. Associations between two calf mortality rates, detection of C. parvum and rotavirus, and predictors were examined with GLM models. In farms with routine vaccination against respiratory diseases, 31-days mortality rate was 4.2% +/-1.26 compared to 7.6% +/-0.97 (p = 0.040) on non-vaccinating farms. Six-months mortality was lower in farms that continued feeding milk to calves during periods of diarrhea compared to farms that did not (6.9% +/-0.8 vs. 12.4% +/-2.3). In case of a routine shifting of calves from the calving box into calf boxes less C. parvum was detected compared to an individual moving of calves (33.3% +/-2.6 vs. 19.6% +/-5.3; p = 0.024). Our model confirms a positive association between occurrence of aqueous feces and frequency of detection of C. parvum (45.4% +/-23.6 vs. 21.4% +/-18.7; p < 0.001). Frequency of detection of rotavirus was lower in farms that reported a defined amount of applicated colostrum per calf than in farms that presented a range of colostrum instead of a defined amount. This study indicates the potential for mitigation of risk factors for mortality in calves.
The effect of magnetism on hydrogen adsorption and subsurface diffusion through face-centred cubic (fcc) γ-Fe(0 0 1) was investigated using spin-polarised density functional theory (s-DFT). The non-magnetic (NM), ferromagnetic (FM), and antiferromagnetic single (AFM1) and double layer (AFMD) structures were considered. For each magnetic state, the hydrogen preferentially adsorbs at the fourfold site, with adsorption energies of 4.07, 4.12, 4.03 and 4.05 eV/H atom for the NM, FM, AFM1 and AFMD structures. A total barrier of 1.34, 0.90, 1.32 and 1.25 eV and a bulk-like diffusion barrier of 0.6, 0.2, 0.4 and 0.3 eV were calculated for the NM, FM, AFM1 and AFMD magnetic states. The Fe atoms nearest to the H atom exhibited a reduced magnetic moment, whereas the next-nearest neighbour Fe atoms exhibited a non-negligible local perturbation in the magnetic moment. The presence of magnetically ordered structures has a minimal influence on the minimum energy path for H diffusion through the lattice and on the adsorption of H atoms on the Fe(0 0 1) surface, but we computed a significant reduction of the bulk-like diffusion barriers with respect to the non-magnetic state of fcc γ-Fe.
This paper presents a databased approach for improving the precision of the moulding sand compressibility in the moulding sand mixer of a foundry. In this approach, the deviation between the measured and the target compressibility is reduced by controlling the water addition. The complex dynamic behaviour of the process variables and their influence on the water addition is modelled with a long short-term memory (LSTM) network. Another LSTM network as control path simulates the impact of the water addition on the compressibility. Simulation and experimental results with the applied model for water prediction in a feedforward control yield relevant improvements of the moulding sand compressibility.
Standen bisher bei den umfassend in der Literatur behandelten Logistikansätzen mehr die Materialwirtschaftsprobleme hinsichtlich der zeitgerechten Beschaffung und der Bestandshöhe im Vordergrund der Betrachtung, so meldet sich jetzt die Zeitwirtschaft mit den damit verbundenen Anstößen auf die Unternehmensstrategie zurück. Der Zeitfaktor ist bei kapitalintensiver Produktion schon immer ein knappes Gut gewesen, mit dem gut gewirtschaftet werden musste, um wettbewerbsfähig zu bleiben. Die derzeitige Wettbewerbssituation mit immer kürzeren Produkt-Entwicklungszeiten, Produkt-Lebenszeiten, Produkt-Herstellzeiten, Produkt-Lieferzeiten verstärkt die enorme Bedeutung des Zeitfaktors als Wert oder Bezugsgröße für Kosten, Termine oder Kapazitäten.
Kleine Losgrößen, bedingt durch immer neue Kundenanforderungen nach speziellen Produktausführungen, lassen aus Wettbewerbsgründen eine konventionelle Massenproduktion mit unfelxiblen Produktionsabläufen nicht mehr zu. Neue Wege sind nötig, um gegenüber der Konkurrenz - besonders aus Fernost - auch in Zukunft wettbewerbsfähig zu bleiben. Dabei hat gerade diese Konkurrenz mnachen Anstoss zur Veränderung durch für uns ungewohnte Wettbewerbsstrategien gegeben. Auch wenn viele der Grundlagen und Methoden dieser Strategien aus Europa stammen, wurden sie sehr geschickt und innovativ den dortigen gesellschaftlichen und technologischen Randbedingungen angepasst. Nun sind sie in anderer Form bei uns wieder ins Bewusstsein zurückgekehrt. Dies gilt insbesondere für Lean Production, die "schlanke" Produktion. Hier können die Fachleute bei uns lernen, wie sich durch Mitarbeitermotivierung, Vereinfachung und Dezentralisierung der Abläufe der Weltkostenstand wieder erreichen lässt.
Die Milchwirtschaft will höhere Preise für Speisequark erlösen. Begründet wird dies mit der in der Bundesrepublik Deutschland gesetzlich verordneten Trockenmasseanhebung des Speisequarks von 17% auf 18%. Da diese Änderung zum 1. Januar 1987 bereits in Kraft trat und den Molkereiunternehmen lange vorher bekannt war, ist die Frage zu stellen, warum eine Änderung der variablen Kosten, von der alle Hersteller gleichermaßen betroffen sind, so schwer am Markt in entsprechende Preisanhebungen umzusetzen ist.
Die Funktion eines Gebäudes, seine flächenmäßige Ausdehnung und seine Gliederung sowie seine Einbettung in die Umgebung bestimmen letztendlich die Dachkonstruktion. Der Planer steht hierbei vor der Aufgabe, unter Beachtung aller bauphysikalischen wie bautechnischen Gegebenheiten ein Optimum an gestalterischer Qualität bei Respektierung wirtschaftlicher und baupraktischer Belange zu realisieren, wobei zu beachten ist, dass gerade das Dach von den die Gebäudehülle bildenden Bauteilen der größten und unmittelbarsten Beanspruchung unterliegt.
Material tests were performed on a rediscovered Klimt-artwork “Trompetender Putto”. We performed studies on the red colored spots, mainly taken from non-restored parts. MIMOS II Fe-57 Mössbauer spectroscopy (novelty in art-pigment analysis) mainly reveals haematite and crystallized goethite in red colors. Electron microscopy can identify various layers of the original and overpainting of an artwork. The number of layers fluctuates between three and four chemically painted areas. The portable X-ray fluorescence analysis enables to reduce the pigment list to containing mercury (cinnabar), lead, zinc, iron and titanium. Infrared-lightirradiation visualizes the different age of the pigments.
Obwohl die Klebtechnik eines der ältesten Fügeverfahren der Welt ist, sind die Kenntnisse über diese Technik häufig noch sehr gering. Dies zeigt sich an vielen Stellen, beim Verkaufsgespräch von Klebstoffen, aber auch in Beiträgen zu klebtechnischen Seminaren. Es werden manchmal "Merk"würdige Ansichten über das Kleben geäußert.
Kleben im Kraftfahrzeugbau
(1987)
Klebemöglichkeiten von PTFE
(1990)
Die hohe Beständigkeit und die antiadhäsiven Eigenschaften von Polytetrafluorethylen (PTFE) erschweren das Kleben dieses Kunststoffes beträchtlich. Da PTFE praktisch unlöslich ist, können Diffusionsklebverbindungen nicht hergestellt werden und Adhäsionsklebverbindungen haben nur eine geringe Festigkeit. Es ist jedoch durch entsprechende Behandlungen möglich, die Oberfläche so zu verändern, dass hochfeste Adhäsionsklebverbindungen möglich sind.
Investigations on Transfer of Pathogens between Foster Cows and Calves during the Suckling Period
(2021)
To date, there have been few studies on the health effects of foster cow systems, including the transmission of mastitis-associated pathogens during suckling. The present study aimed to compare the pathogens detected in the mammary glands of the foster cow with those in the oral cavities of the associated foster calves and to evaluate the resulting consequences for udder health, calf health and internal biosecurity. Quarter milk sampling of 99 foster cows from an organic dairy farm was conducted twice during the foster period. Oral cavity swabs were taken from 345 foster calves. Furthermore, quarter milk samples were collected from 124 biological dams to investigate possible transmission to the foster cows via the suckling calves. All samples were microbiologically examined and confirmed by MALDI-TOF (matrix-assisted laser desorption time-offlight mass-spectrometry). Using RAPD-PCR (randomly amplified polymorphic DNA polymerase chain reaction), strain similarities were detected for Pasteurella multocida, Staphylococcus aureus, S. sciuri and Streptococcus (Sc.) suis. Transmission of P. multocida and S. aureus probably occurred during suckling. For S. sciuri and Sc. suis, environmental origins were assumed. Transmission from dam to foster cow with the suckling calf as vector could not be clearly demonstrated.
Corynebacterium spp. are frequently detected in bovine quarter milk samples, yet their impact on udder health has not been determined completely. In this longitudinal study, we collected quarter milk samples from a dairy herd of approximately 200 cows, ten times at 14 d intervals. Bacteriologically, Catalase-positive and Gram-positive rods were detected in 22.7% of the samples. For further species diagnosis, colonies were analyzed by MALDITOF MS. Corynebacterium bovis, C. amycolatum, C. xerosis and 10 other Corynebacterium spp. were detected. The three aforementioned species accounted for 88.4%, 8.65% and 0.94% of all cultured Corynebacterium spp., respectively. For further evaluation of infection dynamics, the following three infection definitions were applied: A (2/3 consecutive samples positive for the same species), B (≥1000 cfu/mL in one sample), C (isolated from a clinical mastitis case). Infections according to definition B occurred most frequently and clinical mastitis with Corynebacterium spp. occurred once during sampling. Life tables were used to determine the duration of infection. According to infection definition A, infection durations of 111 d and 98 d were obtained for C. bovis and C. amycolatum, respectively. Exemplarily, longer lasting infections were examined for their strain diversity by RAPD PCR. A low strain diversity was found in the individual quarters that indicates a longer colonization of the udder parenchyma by C. bovis and C. amycolatum.
To reduce the negative effects of mastitis in dairy heifers in early lactation on the future milking performance, the aim of this study was to define the time-related period of intramammary infections and to relate this to risk factors at heifer and quarter level for intramammary infections and subclinical mastitis. In total, 279 German Holstein Frisian heifers in three farms in Northern and Eastern Germany were included in this study. Quarter milk samples for cytomicrobiological examination were collected 3 +- 1 days after calving and 17 +- 3 days after calving, and risk factors
at heifer and quarter level associated with intramammary infections and clinical mastitis were recorded during the trial period. Data were analyzed using logistic regression procedures and odds ratios were calculated. Calving at older ages increased the odds of intramammary infections with non-aureus staphylococci (NAS) and coryneforms 17 +- 3 days after calving compared to heifers calving at a younger age. Detaching of milking cups during milking is a risk factor for new infections between day 3 +- 1 and 17 +- 3 postpartum. The milk yield after calving is associated with a decrease in intramammary infections with environmental pathogens and clinical mastitis. A high milk yield assists the development of udder edema with an increased risk of intramammary infections with NAS and coryneforms. An increased somatic cell count (SCC) after calving increased the odds of intramammary infections with contagious pathogens 17 +- 3 days postpartum. The early lactation has an important influence on udder health and intramammary infections postpartum in dairy heifers. Udder quarters eliminated pathogens during early lactation by 6.9% for cases in
this study. New infections manifest themselves up until 17 +- 3 days postpartum, especially with Corynebacterium spp. and NAS. In total, 82.9% of the infected quarters showed new infections with another pathogen species 17 +- 3 days postpartum than 3 +- 1 days postpartum. In conclusion, the early lactation has an important influence on udder health and intramammary infections postpartum in heifers with the possibility that udder quarters eliminate pathogens, but also the danger that new infections manifest themselves. Thus, the prevention of new infections by minimizing the associated risk factors is of great importance.
During machine milking, pathogenic microorganisms can be transmitted from cow to cow through liners. Therefore, in Germany, a spray method for the intermediate disinfection of the milking cluster is often used for prevention. This method of cluster disinfection is easy to perform, requires little time and no extra materials, and the disinfection solution is safe from outside contamination in the spray bottle. Since no data on a systematic efficacy trial are available, the aim of this study was to determine the microbial reduction effect of intermediate disinfection. Therefore, laboratory and field trials were conducted. In both trials, two sprays of 0.85 mL per burst of different disinfectant solutions were sprayed into the contaminated liners. For sampling, a quantitative swabbing method using a modified wet–dry swab (WDS) technique based on DIN 10113-1: 1997-07 was applied. Thus, the effectiveness of disinfectants based on Peracetic Acid, Hydrogen Peroxide and Plasma-Activated Buffered Solution (PABS) was compared. In the laboratory trial, the inner surfaces of liners were contaminated with pure cultures of Escherichia (E.) coli, Staphylococcus (S.) aureus, Streptococcus (Sc.) uberis and Sc. agalactiae. The disinfection of the contaminated liners with the disinfectants resulted in a significant reduction in bacteria with values averaging 1 log for E. coli, 0.7 log for S. aureus, 0.7 log for Sc. uberis and 0.8 log for Sc. agalactiae. The highest reduction was obtained for contamination with E. coli (1.3 log) and Sc. uberis (0.8 log) when PABS was applied and for contamination with S. aureus (1.1 log) and Sc. agalactiae (1 log) when Peracetic Acid Solution (PAS) was used. Treatment with sterile water only led to an average reduction of 0.4 log. In the field trial, after the milking of 575 cows, the liners were disinfected and the total microorganism count from the liner surface was performed. The reduction was measured against an untreated liner within the cluster. Although a reduction in microorganisms was achieved in the field trial, it was not significant. When using PAS, a log reduction of 0.3 was achieved; when using PABS, a log reduction of 0.2 was obtained. The difference between the two disinfection methods was also not significant. Treatment with sterile water only led to a reduction of 0.1 log. The results show that spray disinfection under these circumstances does result in a reduction in the bacteria on the milking liner surface, but for effective disinfection a higher reduction would be preferred.
Die Durchsetzung der Flexibilität als wesentlicher Faktor zur Absicherung der Wettbewerbsposition eines Unternehmens beinhaltet die konsequente Hinwendung zur Markt- beziehungsweise Kundenorientierung. Denn es geht im Kern darum, alle Anstrengungen im Unternehmen darauf zu konzentrieren, dass der Kunde das nach seinen Vorgaben erstellte Produkt in kürzester Zeit ausgeliefert bekommt, wobei die Qualitätsziele nach Gebrauchstauglichkeit und Zuverlässigkeit des Produktes voll erfüllt sein müssen. Die dafür notwendige Qualitätssicherung muss deshalb im Sinne einer Prozesskette in die Leistungserstellung eingebunden werden, was im Artikel verdeutlicht wird.
The adsorption of O atoms on the Fe(1 1 0) surface has been investigated by density functional theory for increasing degrees of oxygen coverage from 0.25 to 1 monolayer, to follow the evolution of the Osingle bondFe(1 1 0) system into an FeO(1 1 1)-like monolayer. We found that the quasi-threefold site is the most stable adsorption site for all coverages, with adsorption energies of ∼2.8–4.0 eV per O atom. Oxygen adsorption results in surface geometrical changes such as interlayer relaxation and buckling, the latter of which decreases with coverage. The calculated vibrational frequencies range from 265 to 470 cm−1 for the frustrated translational modes and 480–620 cm−1 for the stretching mode, and hence are in good agreement with the experimental values reported for bulk FeO wüstite. The hybridization of the oxygen 2p and iron 3d orbitals increases with oxygen coverage, and the partial density of states for the Osingle bondFe(1 1 0) system at full coverage resembles the one reported in the literature for bulk FeO. These results at full oxygen coverage point to the incipient formation of an FeO(1 1 1)-like monolayer that would eventually lead to the bulk FeO oxide layer.
The present research study investigated the susceptibility of common mastitis pathogens—obtained from clinical mastitis cases on 58 Northern German dairy farms—to routinely used antimicrobials. The broth microdilution method was used for detecting the Minimal Inhibitory Concentration (MIC) of Streptococcus agalactiae (n = 51), Streptococcus dysgalactiae (n = 54), Streptococcus uberis (n = 50), Staphylococcus aureus (n = 85), non-aureus staphylococci (n = 88), Escherichia coli (n = 54) and Klebsiella species (n = 52). Streptococci and staphylococci were tested against cefquinome, cefoperazone, cephapirin, penicillin, oxacillin, cloxacillin, amoxicillin/clavulanic acid and cefalexin/kanamycin. Besides cefquinome and amoxicillin/clavulanic acid, Gram-negative pathogens were examined for their susceptibility to marbofloxacin and sulfamethoxazole/trimethoprim. The examined S. dysgalactiae isolates exhibited the comparatively lowest MICs. S. uberis and S. agalactiae were inhibited at higher amoxicillin/clavulanic acid and cephapirin concentration levels, whereas S. uberis isolates additionally exhibited elevated cefquinome MICs. Most Gram-positive mastitis pathogens were inhibited at higher cloxacillin than oxacillin concentrations. The MICs of Gram-negative pathogens were higher than previously reported, whereby 7.4%, 5.6% and 11.1% of E. coli isolates had MICs above the highest concentrations tested for cefquinome, marbofloxacin and sulfamethoxazole/trimethoprim, respectively. Individual isolates showed MICs at comparatively higher concentrations, leading to the hypothesis that a certain amount of mastitis pathogens on German dairy farms might be resistant to frequently used antimicrobials.
The reactivity of graphene at its boundary region has been imaged using non-linear spectroscopy to address the controversy whether the terraces of graphene or its edges are more reactive. Graphene was functionalised with phenyl groups, and we subsequently scanned our vibrational sum-frequency generation setup from the functionalised graphene terraces across the edges. A greater phenyl signal is clearly observed at the edges, showing evidence of increased reactivity in the boundary region. We estimate an upper limit of 1 mm for the width of the CVD graphene boundary region.
In der Bundesrepublik Deutschland gibt es rund 200000 Lieferstellen für Molkereiprodukte vom industriellen Großverbraucher bis zum Facheinzelhändler mit Milchproduktenangebot. Gut die Hälfte der gesamten Nachfrage schöpfen die Zentralläger sowie die Geschäfte des Lebensmitteleinzelhandels ab, wobei die Belieferung des LEH weitestgehend auf Strecke erfolgt. - Dipl.-Wirtsch.-Ing. Heinrich Wietbrauk von der Bundesanstalt für Milchforschung in Kiel analysiert für „dynamik im handel" die milchwirtschaftlichen Warenströme in Deutschland.
Eine schnelle Erfassung aller Wartezeiten und Störungen im Produktionsablauf und ihre richtige kostenmäßige Bewertung zu einer wirksamen Kontrolle der Gemeinkosten in der Produktion ist schon seit langem eine betriebliche Forderung. Ihre Erfüllung scheiterte bisher häufig an fehlenden organisatorischen Voraussetzungen und den nicht für diese Zwecke geeigneten EDV-Sachmitteln. Mit Hilfe von online konzipierten, im Dialog arbeitenden BDE-Systemen können diese Mängel jetzt behoben werden. Schwachstellen im Prozess lassen sich aktuell lokalisieren und damit auch rasch beseitigen. Das im folgenden hier vorgestellte Programm zur Erfassung der benötigten Daten ist gleichzeitig die Kernzelle eines zur Planung und Steuerung des Auftragsbearbeitungsprozesses eingesetzten Logistiksystems, mit dem noch eine große Anzahl weiterer organisatorischer Aufgaben gelöst werden kann. Betrachtungsschwerpunkt in diesem Beitrag ist die verursachungsgerechte Erfassung von Gemeinkosten im Prozess.
Food protein hydrolysates are often produced in unspecific industrial batch processes. The hydrolysates composition underlies process-related fluctuations and therefore the obtained peptide fingerprint and bioactive properties may vary. To overcome this obstacle and enable the production of specific hydrolysates with selected peptides, a ceramic capillary system was developed and characterized for the continuous production of a consistent peptide composition. Therefore, the protease Alcalase was immobilized on the surface of aminosilane modified yttria stabilized zirconia capillaries with a pore size of 1.5 μm. The loading capacity was 0.3 μg enzyme per mg of capillary with a residual enzyme activity of 43%. The enzyme specific peptide fingerprint produced with this proteolytic capillary reactor system correlated with the degree of hydrolysis, which can be controlled over the residence time by adjusting the flow rate. Common food proteins like casein, sunflower and lupin protein isolates were tested for continuous hydrolysis in the developed reactor system. The peptide formation was investigated by high-performance liquid chromatography. Various trends were found for the occurrence of specific peptides. Some are just intermediately occurring, while others cumulate by time. Thus, the developed continuous reactor system enables the production of specific peptides with desired bioactive properties.
Flexibel mit „make or buy"
(1989)
Milk concentrates are used in the manufacturing of dairy products such as yogurt and cheese or are processed into milk powder. Processes for the nonthermal separation of water and valuable milk ingredients are becoming increasingly widespread at farm level. The technical barriers to using farm-manufactured milk concentrate in dairies are minimal, hence the suspicion that the practice of on-farm raw milk concentration is still fairly uncommon for economic reasons. This study, therefore, set out to investigate farmers’ potential willingness to adopt a raw milk concentration plant. The empirical analysis was based on discrete choice experiments with 75 German dairy farmers to identify preferences and the possible adoption of on-farm raw milk concentration. The results showed that, in particular, farmers who deemed the current milk price to be insufficient viewed on-farm concentration using membrane technology as an option for diversifying their milk sales. We found no indication that adoption would be impeded by a lack of trustworthy information on milk processing technologies or capital.
In den letzten Jahren hat sich der Trend zu forcierter Rationalisierung, zur Automatisierung und Mechanisierung der Produktion beschleunigt. Automatisierung erfordert aber hohe Inverstitionen und lässt so den Fixkostenblock wachsen. Bei einem Rückgang der Kapazitätsauslastung rutscht das Unternehmen aber rasch in die Verlustzone. Deshalb erscheint eine Rückbesinnung auf eher flexiblere, arbeitsorientierte Organisationskonzepte sinnvoll. Vorgestellt wird ein kybernetisches Regelkreismodell mit flacher Hierarchie als "Klammer" und sich weitgehend selbstregulierenden Unternehmenseinheiten.
Severe mastitis can lead to considerable disturbances in the cows’ general condition and even to septicemia and death. The aim of this cross-sectional study was to identify factors associated with the severity of the clinical expression of mastitis. Streptococcus (Str.) uberis (29.9%) was the most frequently isolated pathogen, followed by coliform bacteria (22.3%). The majority of all mastitis cases (n = 854) in this study were either mild or moderate, but 21.1% were severe. It can be deduced that the combination of coliform pathogens and increasing pathogen shedding of these showed associations with severe mastitis. Furthermore, animal-related factors associated with severe disease progression were stages of lactation, and previous diseases in the period prior to the mastitis episode. Cows in early lactation had more severe mastitis. Ketosis and uterine diseases in temporal relation to the mastitis were associated with more severe mastitis in the diseased cows. Hypocalcemia was significantly associated with milder mastitis. As another factor, treatment with corticosteroids within two weeks before mastitis was associated with higher severity of mastitis. Knowledge of these risk factors may provide the basis for randomized controlled trials of the exact influence of these on the severity of mastitis.
Background: This basically anatomical study focuses on two items; firstly, the establishment of a system for the cartographic subdivision of the neopallium; secondly, the topographical correlation of extracranial landmarks and intracranial sites on the neopallium.
Materials and methods: The surface of the neopallium was subdivided into 15 sectors with reference to a newly introduced pattern of Primary Sulci. The topographical link between extracranial landmarks and certain intracranial sites (i.e. neopallium sectors) was elaborated by using a simple stereotactic device and a computer-assisted measurement device. Measurements were performed between points on the head's outer surface and on the isolated brain.
Results and Conclusions: The introduction of an anatomical three-dimensional coordinate system was an essential key issue for this investigation. This setting facilitated the measurements and calculations of the so-called indirect distances that were characterised by their alignment along the three orthogonal axes (x, y, z) of the anatomical coordinate system. The inter-individual comparison (16 adult horses [Equus caballus]) of the indirect distances revealed that each sector centre lay within a distinct morphometric residence area. The measured and calculated data also showed that each sector centre could be assigned to its proper extracranial landmark that - in comparison with other landmarks - was best suited for the optimal allocation of the sector centre point.
Recent research efforts have highlighted the potential of hybrid composites in the context of additive manufacturing. The use of hybrid composites can lead to an enhanced adaptability of the mechanical properties to the specific loading case. Furthermore, the hybridization of multiple fiber materials can result in positive hybrid effects such as increased stiffness or strength. In contrast to the literature, where only the interply and intrayarn approach has been experimentally validated, this study presents a new intraply approach, which is experimentally and numerically investigated. Three different types of tensile specimens were tested. The non-hybrid tensile specimens were reinforced with contour-based fiber strands of carbon and glass. In addition, hybrid tensile specimens were manufactured using an intraply approach with alternating carbon and glass fiber strands in a layer plane. In addition to experimental testing, a finite element model was developed to better understand the failure modes of the hybrid and non-hybrid specimens. The failure was estimated using the Hashin and Tsai–Wu failure criteria. The specimens showed similar strengths but greatly different stiffnesses based on the experimental results. The hybrid specimens demonstrated a significant positive hybrid effect in terms of stiffness. Using FEA, the failure load and fracture locations of the specimens were determined with good accuracy. Microstructural investigations of the fracture surfaces showed notable evidence of delamination between the different fiber strands of the hybrid specimens. In addition to delamination, strong debonding was particularly evident in all specimen types.
Of late, decrease in mineral oil supplies has stimulated research on use of biomass as an alternative energy source. Climate change has brought problems such as increased drought and erratic rains. This, together with a rise in land degeneration problems with concomitant loss in soil fertility has inspired the scientific world to look for alternative bio-energy species. Euphorbia tirucalli L., a tree with C3/CAM metabolism in leaves/stem, can be cultivated on marginal, arid land and could be a good alternative source of biofuel.
We analyzed a broad variety of E. tirucalli plants collected from different countries for their genetic diversity using AFLP. Physiological responses to induced drought stress were determined in a number of genotypes by monitoring growth parameters and influence on photosynthesis. For future breeding of economically interesting genotypes, rubber content and biogas production were quantified.
Cluster analysis shows that the studied genotypes are divided into two groups, African and mostly non-African genotypes. Different genotypes respond significantly different to various levels of water. Malate measurement indicates that there is induction of CAM in leaves following drought stress. Rubber content varies strongly between genotypes. An investigation of the biogas production capacities of six E. tirucalli genotypes reveals biogas yields higher than from rapeseed but lower than maize silage.
Erfolgsfaktoren im Griff
(1993)
Die empfindliche Verteuerung des Rohöls im Laufe der letzten Jahre und die in ihrem Sog erfolgten Preissteigerungen auch für die anderen Energieträger haben Energie zu einem besonders kostbaren Wirtschaftsgut werden lassen. Es ist ganz deutlich geworden, dass Energie in allen Lebens- und Produktionsbereichen äußerst sparsam verwendet und optimal genutzt werden muss. Mittel- und langfristig gesehen sind daher gezielt Anstrengungen zu unternehmen, nicht einen Brennstoff durch einen anderen zu ersetzen, sondern - wo immer auch möglich - die natürlcihen Energiequellen zu nutzem.
In this study, we calculated the energetics of hydrogen atoms adsorbing on and diffusing into the first few layers of γ-Fe for the (100), (110) and (111) surfaces and for the non-magnetic (NM), ferromagnetic (FM), and antiferromagnetic single (AFM1) and double layer (AFMD) structures. These studies are relevant as they atomistically simulate the early stages of hydrogen embrittlement in steels. We employed density functional theory to establish adsorption sites and energies for each plane and the minimum energy pathways for diffusion through the first few layers with associated activation barriers. Adsorption energies for all cases vary between ∼3.7 and 4.4 eV, and the energy barriers to diffusion in the bulk region vary between ∼0.2 and 1.2 eV for the twelve cases, with the highest and lowest bulk diffusion barriers occurring in the NM(111) and the FM(100) case, respectively. We conclude that the texturing of steels in order to expose certain cleavage planes or magnetic structures can decrease the likelihood of hydrogen embrittlement.
The bio-based plastic market is forecast to grow in the next years. With a growing market share and product range, the implementation of circular thinking is becoming more and more important also for bio-based plastics to enable a sound circular economy for these group of plastics. Therefore, it is important to assess the environmental performance for different end-of-life options of bio-based plastics from an early stage on. This review presents a comprehensive overview on the current status quo of different end-of-life options for bio-based plastics from an environmental perspective. Based on the status quo and the corresponding impact assessment results, the global plastic demand as well as the technical substitution potential of bio-based plastics, the environmental saving potential in case of the different end-of-life options was calculated. The review shows that there is a focus on polylactic acid (PLA) regarding end-of-life assessment, with studies covering all end-of-life options. The focus of the impact assessment has been set on global warming potential (GWP). With respect to GWP, the analysis of a future global potential of PLA showed, for mechanical recycling, the highest saving potential with 94.1 Mio. t CO2-eq. per year in comparison to virgin material.
The properties of these carbon nanostructures are determined by the structure and orientation of the graphitic domains during pyrolysis of carbon precursors. In this work, we investigated systematically the impact of creep stress during the stabilization process on the cyclization and molecular orientation of polyacrylonitrile as well as the graphitized structure after high temperature carbonization. Therefore, polyacrylonitrile (PAN) is electrospun and then stabilized with and without application of creep stress at different temperatures. The effect of creep stress on cyclization was monitored via Fourier transform IR spectroscopy (FTIR) and it was found that the degree of cyclization varies with the application of creep stress during the initial stages of cyclization at low temperatures (190°C and 210°C) in contrast to cyclization done at higher temperature (230°C). Herman molecular orientation factor was evaluated by polarized FTIR for PAN nanofibers cyclized with and without creep stress at 230°C-10 h. Subsequently, carbonization was performed at 1000°C and 1200°C for nanofibers cyclized at 230°C-10 h. Our results from XRD and Raman spectroscopy shows that the degree of graphitization and ordering of graphitic domains was enhanced for PAN nanofibers that were creep stressed during the cyclization process, even though both PAN nanofibers cyclized with creep stress and without creep stress showed the same amount of cyclized material. This increased degree of graphitization can be tracked to application of creep stress during the stabilization process which obviously favors the formation of sp2-hybridized carbon planes in the carbonization process. This finding highlights the impact of mechanical stress linking the cyclization of PAN nanofibers to graphitization.
Our results will pave the way for a deeper understanding of mechano-chemical processes to fabricate well-aligned graphitic domains which improves the mechanical and electrical properties of CNFs.