Hot tool and high temperature welding of filled reinforced thermoplastics

Abstract

The existing technologies of hot tool butt and high temperature welding are changing with the additives and fillers which are being added to thermoplastics to improve their properties. This necessitates modification of the welding apparatus. The details are discussed using PVC-VM and chalk-filled polypropylene as examples.     

Genetic Dissection of Phosphorus Use Efficiency in a Maize Association Population under Two P Levels in the Field

Phosphorus (P) deficiency is an important challenge the world faces while having to increase crop yields. It is therefore necessary to select maize (Zea may L.) genotypes with high phosphorus use efficiency (PUE). Here, we extensively analyzed the biomass, grain yield, and PUE-related traits of 359 maize inbred lines grown under both low-P and normal-P conditions. A significant decrease in grain yield per plant and biomass, an increase in PUE under low-P condition, as well as significant correlations between the two treatments were observed. In a genome-wide association study, 49, 53, and 48 candidate genes were identified for eleven traits under low-P, normal-P conditions, and in low-P tolerance index (phenotype under low-P divided by phenotype under normal-P condition) datasets, respectively. Several gene ontology pathways were enriched for the genes identified under low-P condition. In addition, seven key genes related to phosphate transporter or stress response were molecularly characterized. Further analyses uncovered the favorable haplotype for several core genes, which is less prevalent in modern lines but often enriched in a specific subpopulation. Collectively, our research provides progress in the genetic dissection and molecular characterization of PUE in maize.     

Cost-benefit analysis for disruption prevention in low-volume assembly

Manufacturing companies face rising pressure due to increased competition. Traditionally, companies have merely concentrated on offering impeccable, cost-efficient products. Today, however, flexibility and on-time delivery are additional requirements to satisfy the customers. At the same time, disruptions in production, especially in low-volume assembly, still frequently occur, leading to economic losses and delayed customer deliveries. The approach proposed in this paper strives for improving the disruption situation in low-volume assemblies. A detailed disruption management methodology has been developed, aiming at realizing an efficient reduction of disruptions, while at the same time considering the specific characteristics of low-volume assembly. The methodology is supported by a catalog of pre-emptive measures. These measures are known to reduce the disruptions’ occurrence or to diminish their consequences. In general, the approach pursues the basic idea to implement particularly those measures, which have the best cost-benefit-ratio. Based on the analysis of the cost-benefit-ratio of each measure, the developed methodology aims at improving the disruption situation in assembly and thus providing a high on-time delivery rate. The usability of the methodology for the low-volume assembly context has been confirmed by assembly experts on the basis of an application of the methodology in an exemplary case study.     

Platelet activating factor production and proinflammatory gene expression in endotoxin-challenged bovine mammary endothelial cells

The bovine mammary gland responds to gram-negative pathogens by stimulating the production of cytokines and other proinflammatory mediators that orchestrate the migration of leukocytes into tissues. Platelet activating factor (PAF), interleukin 1β (IL-1β), IL-8, and intercellular adhesion molecule 1 (ICAM1) are among the several inflammatory factors involved in the early activation and migration of leukocytes into the mammary gland during the initial stages of coliform mastitis. Several different cell types within the mammary gland are capable of expressing these potent pro-inflammatory mediators. The objective of this study was to characterize the expression profile of vascular-derived inflammatory molecules that may play a role in the pathogenesis of bovine coliform mastitis. Isolated bovine mammary gland endothelial cells were stimulated in culture for up to 12 h with endotoxin obtained from Escherichia coli, and the temporal expression of proinflammatory cytokines and adhesion molecules relative to endogenous PAF biosynthesis was evaluated. Results from the in vitro time course experiment showed that vascular-derived PAF biosynthesis began as early as 30 min and peaked at 1 h following endotoxin challenge. The biosynthesis of PAF preceded the endotoxin-induced IL-1β, IL-8, and ICAM1 mRNA expression that increased after 1 h and reached peak expression between 4 and 12 h following stimulation. Inhibiting the effects of endogenous PAF with a receptor antagonist suggests that vascular-derived PAF is an early proinflammatory mediator that plays at least a partial role in the subsequent expression of IL-1β, IL-8, and ICAM1 during endotoxin challenge. Furthermore, endotoxin-induced PAF biosynthesis by bovine mammary gland endothelial cells is regulated to some extent by phospholipase D activity and phosphatidic acid production. The results from this study support the contention that mammary gland endothelial cells can contribute to the production of important proinflammatory mediators that are typically associated with coliform mastitis.     

Shedding light on solar technologies—A techno-economic assessment and its policy implications

Solar power technologies will have to become a major pillar in the world's future energy system to combat climate change and resource depletion. However, it is unclear which solar technology is and will prove most viable. Therefore, a comprehensive comparative assessment of solar technologies along the key quantitative and qualitative competitiveness criteria is needed. Based on a literature review and detailed techno-economic modeling for 2010 and 2020 in five locations, we provide such an assessment for the three currently leading large-scale solar technologies. We show that today these technologies cannot yet compete with conventional forms of power generation but approach competitiveness around 2020 in favorable locations. Furthermore, from a global perspective we find that none of the solar technologies emerges as a clear winner and that cost of storing energy differs by technology and can change the order of competitiveness in some instances. Importantly, the competitiveness of the different technologies varies considerably across locations due to differences in, e.g., solar resource and discount rates. Based on this analysis, we discuss policy implications with regard to fostering the diffusion of solar technologies while increasing the efficiency of policy support through an adequate geographical allocation of solar technologies.     

Gasification inhibition in chemical-looping combustion with solid fuels

Chemical-looping combustion (CLC) is a novel technology that can be used to meet growing demands on energy production without CO₂ emissions. The CLC process includes two reactors, an air and a fuel reactor. Between these two reactors oxygen is transported by an oxygen carrier, which most often is a metal oxide. This arrangement prevents mixing of N₂ from the air with CO₂ from the combustion giving combustion gases that consist almost entirely of CO₂ and H₂O. The technique reduces the energy penalty that normally arises from the separation of CO₂ from other flue gases, hence, CLC could make capture of CO₂ cheaper. For the application of CLC to solid fuels, the char remaining after devolatilization will react indirectly with the oxygen carrier via steam gasification. It has been suggested that H₂, and possibly CO, has an inhibiting effect on steam gasification in CLC. In this work experiments were conducted to investigate this effect. The experiments were conducted in a laboratory fluidized-bed reactor that was operating cyclically with alternating oxidation and reduction periods. Two different oxygen carriers were used as well as an inert sand bed. During the reducing period varying concentrations of CO or H₂ were used together with steam while the oxidation was conducted with 10% O₂ in N₂. The temperature was constant at 970 °C for all experiments. The results show that CO does not directly inhibit the gasification whereas the partial pressure of H₂ had a significant influence on fuel conversion. The results also suggest that dissociative hydrogen adsorption is the predominant hydrogen inhibition mechanism under the laboratory conditions, thus explaining why char conversion is much faster in a bed of oxygen carrying material, compared to an inert sand bed.