Energy and material efficiency of steel powder metallurgy

Concern about global warming motivates the reduction of greenhouse gas emissions from manufacturing but as yet the environmental impact of the whole powder metallurgy production chain has not been assessed. This paper therefore traces the flow of energy and material through the major powder metallurgy processes from liquid steel to final products and assesses the efficiency of both energy and material use. The results show that there is significant opportunity for reducing energy and material requirements in delivering products. Specific opportunities such as avoiding lasers in additive manufacturing or minimizing heat losses in powder sintering are proposed and evaluated

The deformation of metal powder particles: Hardness and microstructure

© 2017 The Authors. Published by Elsevier Ltd. The modelling of powder densification requires knowledge about the material properties of the particles. Some models use the material properties of the material in bulk as inputs for modelling the densification of assemblies of powder particles. It is important to understand how these properties differ when the material is in powder form. Existing works tend to analyse bulk material or powder exclusively and rarely compare properties such as hardness between the two. This work compares the microstructures and hardness of metal powder with bulk material with the aim of guiding the assumptions made in the modelling of metal powder densification. It is expected that the rapid solidification typical in the atomisation of metals results in significant differences in behaviour when compared with material produced via casting and hot/cold working

The antioxidants resveratrol and N-acetylcysteine enhance anthelmintic activity of praziquantel and artesunate against Schistosoma mansoni

Background: Treatment of schistosomiasis has relied on the anthelmintic drug praziquantel (PZQ) for more than a generation. Despite its celebrated performance for treatment and control of schistosomiasis and other platyhelminth infections, praziquantel has some shortcomings and the inability of this drug to counteract disease sequelae prompts the need for novel therapeutic strategies. Methods: Using a host-parasite model involving Biomphalaria glabrata and Schistosoma mansoni we established mechanical transformation of S. mansoni cercariae into newly transformed schistosomula (NTS) and characterized optimal culture conditions. Thereafter, we investigated the antischistosomal activity and ability of the antioxidants N-acetylcysteine (NAC) and resveratrol (RESV) to augment the performance of praziquantel and/or artesunate (AS) against larval stages of the parasite. Drug effects were evaluated by using an automated microscopical system to study live and fixed parasites and by transmission electron microscopy (TEM). Results: Transformation rates of cercariae to schistosomula reached ~ 70% when the manipulation process was optimized. Several culture media were tested, with M199 supplemented with HEPES found to be suitable for S. mansoni NTS. Among the antioxidants studied, RESV alone or combined with anthelminthic drugs achieved better results rather N-acetylcysteine (NAC). TEM observations demonstrated that the combination of AS + RESV induced severe, extensive alterations to the tegument and subtegument of NTS when compared to the constituent compounds alone. Two anthelmintic-antioxidant combinations, praziquantel-resveratrol [combination index (CI) = 0.74] and artesunate-resveratrol (CI = 0.34) displayed moderate and strong synergy, respectively. Conclusions: The use of viability markers including staining with propidium iodide increased the accuracy of drug screening assays against S. mansoni NTS. The synergies observed might be the consequence of increased action by RESV on targets of AS and PZQ and/or they may act through concomitantly on discrete targets to enhance overall antischistosomal action. Combinations of active agents, preferably with discrete modes of action including activity against developmental stages and/or the potential to ameliorate infection-associated pathology, might be pursued in order to identify novel therapeutic interventions.We express our deepest appreciation to Mrs. Maria Lurdes Delgado for expert maintenance of the schistosome life-cycle and her technical support NV acknowledges support from the Fundação para a Ciência e Tecnologia (FCT, Portugal) and FEDER (European Union) through Project Number IF/00092/2014/CP1255/CT0004. NV thanks FCT by IF position, Fundação Manuel António da Mota (FMAM, Portugal) and Pfizer Portugal for research group support. JMCC thanks FCT for UID/Multi/00211/2019 and Strategic Project UI211. PJB acknowledges support from award RO1CA164719 from the National Cancer Institute (NCI), National Institutes of Health (NIH), USA. The contents of this report are solely the responsibility of the authors and do not necessarily represent the official views of the FCT, FMAM, the NCI, or the NIH

Energy and material efficiency of steel powder metallurgy

Concern about global warming motivates the reduction of greenhouse gas emissions from manufacturing but as yet the environmental impact of the whole powder metallurgy production chain has not been assessed. This paper therefore traces the flow of energy and material through the major powder metallurgy processes from liquid steel to final products and assesses the efficiency of both energy and material use. The results show that there is significant opportunity for reducing energy and material requirements in delivering products. Specific opportunities such as avoiding lasers in additive manufacturing or minimizing heat losses in powder sintering are proposed and evaluated

Global material flow analysis of glass: From raw materials to end of life

Global glass production grew to 150 million tonnes (Mt) in 2014, equating to approximately 21 kg per person. Producing this glass is energy intensive and contributes annual CO2 emissions of some 86Mt. An accurate map of the global glass supply chain is needed to help identify emissions mitigation options from across the supply chain, including process energy efficiency and material efficiency options. This map does not yet exist, so we address this knowledge gap by tracing the production chain from raw materials to end of life and producing a global Sankey diagram of container and flat glass making for 2014. To understand future demand for flat glass we also model the stocks of glass in vehicles and buildings. The analysis shows the relative scale of glass flows and stocks worldwide and provides a baseline for future study of the emission mitigation potential of energy and material efficiency of manufacturing with glass

Differential gene expression between the biotrophic-like and saprotrophic mycelia of the witches' broom pathogen Moniliophthora perniciosa

Moniliophthora perniciosa is a hemibiotrophic fungus that causes witches' broom disease (WBD) in cacao. Marked dimorphism characterizes this fungus, showing a monokaryotic or biotrophic phase that causes disease symptoms and a later dikaryotic or saprotrophic phase. A combined strategy of DNA microarray, expressed sequence tag, and real-time reverse-transcriptase polymerase chain reaction analyses was employed to analyze differences between these two fungal stages in vitro. In all, 1,131 putative genes were hybridized with cDNA from different phases, resulting in 189 differentially expressed genes, and 4,595 reads were clusterized, producing 1,534 unigenes. The analysis of these genes, which represent approximately 21% of the total genes, indicates that the biotrophic-like phase undergoes carbon and nitrogen catabollite repression that correlates to the expression of phytopathogenicity genes. Moreover, downregulation of mitochondrial oxidative phosphorylation and the presence of a putative ngr1 of Saccharomyces cerevisiae could help explain its lower growth rate. In contrast, the saprotrophic mycelium expresses genes related to the metabolism of hexoses, ammonia, and oxidative phosphorylation, which could explain its faster growth. Antifungal toxins were upregulated and could prevent the colonization by competing fungi. This work significantly contributes to our understanding of the molecular mechanisms of WBD and, to our knowledge, is the first to analyze differential gene expression of the different phases of a hemibiotrophic fungus.21789190