44 research outputs found

    Integration of Simulation Driven DfAM and LCC Analysis for Decision Making in L-PBF

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    Laser based powder bed fusion (L-PBF) is used to manufacture parts layer by layer with the energy of laser beam. The use of L-PBF for building functional parts originates from the design freedom, flexibility, customizability, and energy efficiency of products applied in dynamic application fields such as aerospace and automotive. There are challenges and drawbacks that need to be defined and overcome before its adaptation next to rivaling traditional manufacturing methods. Factors such as high cost of L-PBF machines, metal powder, post-preprocessing, and low productivity may deter its acceptance as a mainstream manufacturing technique. Understanding the key cost drivers of L-PBF that influence productivity throughout the whole lifespan of products will facilitate the decision-making process. Functional and operational decisions can yield profitability and increase competitiveness among advanced manufacturing sectors. Identifying the relationships between the phases of the life cycle of products influences cost-effectiveness. The aim of the study is to investigate the life cycle cost (LCC) and the impact of design to it in additive manufacturing (AM) with L-PBF. The article provides a review of simulation driven design for additive manufacturing (simulation driven DfAM) and LCC for metallic L-PBF processes and examines the state of the art to outline the merits, demerits, design rules, and life cycle models of L-PBF. Practical case studies of L-PBF are discussed and analysis of the interrelating factors of the different life phases are presented. This study shows that simulation driven DfAM in the design phase increases the productivity throughout the whole production and life span of L-PBF parts. The LCC model covers the whole holistic lifecycle engineering of products and offers guidelines for decision making. View Full-TextKeywords: design for additive manufacturing; life cycle cost; metal; laser powder bed fusion; productivity</div

    Coagulation factors and natural anticoagulants as surrogate markers of preeclampsia and its subtypes: A case-control study in a Ghanaian population

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    Preeclampsia (PE) is associated with endothelial injury and hemostatic abnormalities. However, the diagnostic role of coagulation parameters and natural anticoagulants in predicting PE has not been explored in Ghana. This study assessed plasma levels of these factors as surrogate markers of PE and its subtypes. This case-control study included 90 women with PE (cases) and 90 normotensive pregnant women (controls). Blood samples were drawn for the estimation of complete blood count and coagulation tests. The prothrombin time (PT), activated partial thromboplastin time (APTT), and the calculation of the international normalized ratio (INR) were determined by an ACL elite coagulometer while the levels of protein C (PC), protein S (PS), antithrombin III (ATIII), and D-dimers were also measured using the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. All statistical analyses were performed using the R Language for Statistical Computing. Results showed significantly (p \u3c .05) shortened APTT (28.25 s) and higher D-dimer levels (1219.00 ng/mL) among PE women, as well as low levels of PC (1.02 g/mL), PS (6.58 g/mL), and ATIII (3.99 ng/mL). No significant difference was found in terms of PT and INR. From the receiver operating characteristic analysis, PC, PS, and ATIII could significantly predict PE and its subtypes at certain cutoffs with high accuracies (area under the curve [AUC] ≥ 0.70). Most women with PE are in a hypercoagulable state with lower natural anticoagulants. PC, PS, and ATIII are good predictive and diagnostic markers of PE and its subtypes (early-onset PE [EO-PE] and late-onset PE [LO-PE]) and should be explored in future studies

    Direct and residual effects of phosphate fertilizer on maize (Zea mays L) grown on an Ultisol in Kumasi, Ghana

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    (Ghana Journal of Agricultural Science, 1987-90, 20-23: 93-100

    Effect of school-based nutrition interventions among primary school children in sub-Saharan Africa: a systematic review protocol

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    Introduction Preadolescents are passing through an intensive growth and development period that will benefit from healthy eating practices. For those attending school, school environments offer several potential benefits and have been demonstrated to influence the quality of dietary intakes and consequentially, nutritional status of school-aged children (SAC). Considering the amount of time children spend in school and the enormous potential of evidence-based interventions, the purpose of this review is to critically appraise peer-reviewed literature addressing the impact of school-based interventions on the nutritional status of SAC aged 6–12 years in sub-Saharan Africa.Methods and analysis A systematic search will be conducted in the following databases and online search records: Medline, CINAHL, Web of Science, Embase, Global health, Global Index Medicus, Cochrane library, Hinari and Google Scholar using search terms and keywords codeveloped with two librarians. An additional search will also be conducted from the reference list of identified literature. Search results of titles and abstracts will be initially screened for eligibility criteria by two independent reviewers and where there is disagreement, a third reviewer will be consulted. Articles meeting these criteria will then undergo a full-text review for the eligibility and exclusion criteria. The Joanna Briggs Institute critical appraisal tool will be used to assess the risk of bias. Data from articles meeting all study criteria will be extracted, analysed and synthesised. A meta-analysis will also be conducted if sufficient data are available.Ethics and dissemination This systematic review is limited to publicly accessible data bases not requiring prior ethical approval to access. The results of the systematic review will be disseminated through publications in peer-reviewed journals as well as conference and stakeholder presentations.PROSPERO registration number CRD42022334829
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