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Spreadability of powders for additive manufacturing: A critical review of metrics and characterisation methods

PARTICUOLOGY 2024年第10期93卷 211-234页

作者： Talebi, Fatemeh A. Haydari, Zobaideh Salehi, Hamid Mehrabi, Mozhdeh Gardy, j.bbar Bradley, Mike Bayly, andrew E. Hassanpour, Ali Univ Leeds Sch Chem & Proc Engn Leeds LS2 9JT England Univ Greenwich Sch Engn Greenwich ME4 4TB England Cormica Ltd Listerhills Sci PkCampus Rd Bradford BD7 1HR England

Powder bed fusion methods of additive manufacturing (AM) require consistent, reproducible, and uniform layers of powder for the reliable production of high-quality parts, where properties of powder are central to achieving this. Among these properties, powder flowability and spreadability play critical roles in determining the quality of these powder layers. While extensive research has been conducted on powder flow and spreading behaviour, and on their characterisation, there is little critical comparison and review of these terms in the context of AM. Such a review is necessary to further develop and enhance our comprehension of spreading dynamics and its relation to powder properties in AM systems. This review paper aims to build a coherent understanding of the correlation between powder characteristics and spreading in powder based additive manufacturing and its impact on manufactured parts. It highlights the current progress in comprehending spreading dynamics, the influence of powder characteristics, environmental conditions, spreading system, and the development of testing tools to assess powder spreadability. Furthermore, the paper critically discusses the challenge of finding appropriate quantitative metrics and recent advances in the use of standardised methods for evaluating powder spreadability. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// ***/licenses/by/4.0/).

关键词： Powder spreading Powder flowability Powder properties Quality of layer and final products DISCRETE ELEMENT SIMULATION PARTICLE-SIZE DISTRIBUTION SPREADING PROCESS FLOW PROPERTIES NUMERICAL-SIMULATION DENSITY BULK FLOWABILITY SEGREGATION BEHAVIOR

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EventLFM:event camera integrated Fourier light field microscopy for ultrafast 3D imaging

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Light(Science & Applications) 2024年第7期13卷 1401-1415页

作者： Ruipeng Guo Qianwan Yang andrew S.Chang Guorong Hu j.seph Greene Christopher V.Gabel Sixian You Lei Tian Department of Electrical and Computer Engineering Boston UniversityBostonMA 02215USA Department of Physiology and Biophysics Boston UniversityBostonMA 02215USA. Neurophotonics Center Boston UniversityBostonMA 02215USA. Research Laboratory of Electronics(RLE)in the Department of Electrical Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA. Department of Biomedical Engineering Boston UniversityBostonMA 02215USA

Ultrafast 3D imaging is indispensable for visualizing complex and dynamic biological *** scanning-based techniques necessitate an inherent trade-off between acquisition speed and space-bandwidth product(SBP).Emerging single-shot 3D wide-field techniques offer a promising alternative but are bottlenecked by the synchronous readout constraints of conventional CMOS systems,thus restricting data throughput to maintain high SBP at limited frame *** address this,we introduce EventLFM,a straightforward and cost-effective system that overcomes these challenges by integrating an event camera with Fourier light field microscopy(LFM),a state-of-theart single-shot 3D wide-field imaging *** event camera operates on a novel asynchronous readout architecture,thereby bypassing the frame rate limitations inherent to conventional CMOS *** further develop a simple and robust event-driven LFM reconstruction algorithm that can reliably reconstruct 3D dynamics from the unique spatiotemporal measurements captured by *** results demonstrate that EventLFM can robustly reconstruct fast-moving and rapidly blinking 3D fluorescent samples at kHz frame ***,we highlight EventLFM’s capability for imaging of blinking neuronal signals in scattering mouse brain tissues and 3D tracking of GFP-labeled neurons in freely moving *** believe that the combined ultrafast speed and large 3D SBP offered by EventLFM may open up new possibilities across many biomedical applications.

关键词： field linking overcome

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Modeling of Total Dissolved Solids (TDS) and Sodium Absorption Ratio (SAR) in the Edwards-Trinity Plateau and Ogallala Aquifers in the Midland-Odessa Region Using Random Forest Regression and eXtreme Gradient Boosting

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j.urnal of Geoscience and Environment Protection 2024年第5期12卷 218-241页

作者： Azuka I. Udeh Osayamen j. Imarhiagbe Erepamo j. Omietimi Department of Geoscience University of Texas Permian Basin Odessa Texas USA Department of Geology University of Pretoria Pretoria South Africa

Efficient water quality monitoring and ensuring the safety of drinking water by government agencies in areas where the resource is constantly depleted due to anthropogenic or natural factors cannot be overemphasized. The above statement holds for West Texas, Midland, and Odessa Precisely. Two machine learning regression algorithms (Random Forest and XGBoost) were employed to develop models for the prediction of total dissolved solids (TDS) and sodium absorption ratio (SAR) for efficient water quality monitoring of two vital aquifers: Edward-Trinity (plateau), and Ogallala aquifers. These two aquifers have contributed immensely to providing water for different uses ranging from domestic, agricultural, industrial, etc. The data was obtained from the Texas Water Development Board (TWDB). The XGBoost and Random Forest models used in this study gave an accurate prediction of observed data (TDS and SAR) for both the Edward-Trinity (plateau) and Ogallala aquifers with the R2 values consistently greater than 0.83. The Random Forest model gave a better prediction of TDS and SAR concentration with an average R, MAE, RMSE and MSE of 0.977, 0.015, 0.029 and 0.00, respectively. For the XGBoost, an average R, MAE, RMSE, and MSE of 0.953, 0.016, 0.037 and 0.00, respectively, were achieved. The overall performance of the models produced was impressive. From this study, we can clearly understand that Random Forest and XGBoost are appropriate for water quality prediction and monitoring in an area of high hydrocarbon activities like Midland and Odessa and West Texas at large.

关键词： Water Quality Prediction Predictive Modeling Aquifers Machine Learning Regression eXtreme Gradient Boosting

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Detection of Gravitational Waves with Semi Classical Features and Resulting Cosmological Implications

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j.urnal of High Energy Physics, Gravitation and Cosmology 2024年第1期10卷 454-467页

作者： andrew Walcott Beckwith Physics Department College of Physics Chongqing University Chongqing China

The author argues in this document that initial vacuum state values possibly responsible for GW generation in relic conditions in the initial onset of inflation may have a temporary unsqueezed, possibly even coherent initial value, which would permit in certain models classical coherent initial gravitational wave states. Furthermore, several arguments pro and con as to if or not initial relic GW should be high frequency will be presented, with the reason given why earlier string models did NOT favor low frequency relic GW from the big bang. What is observed is that large higher dimensions above our 4 Dimensional space time, if recipients of matter-energy from collapse and re birth of the universe are enough to insure low relic GW. The existence of higher dimensions, in itself if the additional dimensions are small and compact will have no capacity to lower the frequency limit values of relic GW, as predicted by Giovannini, et al. in 1995.

关键词： Graviton DM Squeezed States Coherent States High Frequency Gravity Waves

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The use of oral human immunodeficiency virus pre-exposure prophylaxis in pregnant and lactating women in sub-Saharan Africa:considerations,barriers,and recommendations

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Global Health j.urnal 2024年第2期8卷 41-45页

作者： Enos Moyo Grant Murewanhema Perseverance Moyo Tafadzwa Dzinamarira andrew Ross School of Nursing&Public Health College of Health SciencesUniversity of Kwa-Zulu NatalDurbanSouth Africa Faculty of Medicine and Health Sciences University of ZimbabweHarareZimbabwe Medical Centre Oshakati OshakatiNamibia School of Health Systems and Public Health University of PretoriaPretoriaSouth Africa

In sub-Saharan Africa(SSA),63%of new human immunodeficiency virus(HIV)infections in 2021 were among women,particularly adolescent girls,and young *** is a high incidence of HIV among pregnant and lactating women(PLW)in *** is estimated that the risk of HIV-acquisition during pregnancy and the postpartum period more than *** this article,we discuss the safety and effectiveness of drugs used for oral HIV pre-exposure prophylaxis(PrEP),considerations for initiating PrEP in PLW,the barriers to initiating and adhering to PrEP among them and suggest recommendations to address these ***/emtricitabine,the most widely used combination in SSA,is safe,clinically effective,and cost-effective among *** PLW who requests PrEP and has no medical contraindications should receive *** users who are pregnant or lactating may experience barriers to starting and adhering for a variety of reasons,including personal,pill-related,and healthcare facility-related *** address the barriers,we recommend an increased provision of information on PrEP to the women and the communities,increasing and/or facilitating access to PrEP among the PLW,and developing strategies to increase adherence.

关键词： Pre-exposure prophylaxis Pregnancy Lactation Safety Barriers Recommendations

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Advances in magnesium-containing bioceramics for bone repair

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Biomaterials Translational 2024年第1期5卷 3-20页

作者： Qi L. Zhao T. Yan j. Ge W. j.ang W. Wang j. Gholipourmalekabadi M. Lin K. Wang X. Zhang L. Department of Oral and Cranio-Maxillofacial Surgery Shanghai Ninth People’s Hospital College of Stomatology Shanghai Jiao Tong University School of Medicine National Clinical Research Center for Oral Diseases Shanghai Key Laboratory of Stomatology and Shanghai Research Institute of Stomatology Shanghai China Department’s Education Deputy Department of Medical Biotechnology Iran University of Medical Sciences Tehran Iran Institute of Translational Medicine Shanghai University Organoid Research Center Shanghai University Shanghai China

Reconstruction of bone defects or fractures caused by ageing, trauma and tumour resection is still a great challenge in clinical treatment. Although autologous bone graft is considered as gold standard, the source of natural bone is limited. In recent years, regenerative therapy based on bioactive materials has been proposed for bone reconstruction. Specially, numerous studies have indicated that bioactive ceramics including silicate and phosphate bioceramics exhibit excellent osteoinductivity and osteoconductivity, further promote bone regeneration. In addition, magnesium (Mg) element, as an indispensable mineral element, plays a vital role in promoting bone mineralisation and formation. In this review, different types of Mg-containing bioceramics including Mg-containing calcium phosphate-based bioceramics (such as Mg-hydroxyapatite, Mg-biphasic calcium phosphate), Mg-containing calcium silicate-based bioceramics (such as Mg2SiO4, Ca2MgSi2O7and Mg-doped bioglass), Mg-based biocements, Mg-containing metal/polymer-bioceramic composites were systematacially summarised. Additionally, the fabrication technologies and their materiobiological effects were deeply discussed, Clinical applications and perspectives of magnesium-containing bioceramics for bone repair are highlighted. Overall, Mg-containing bioceramics are regarded as regenerative therapy with their optimised performance. Furthermore, more in-depth two-way researches on their performance and structure are essential to satisfy their clinical needs. © 2024, Chinese Medical Multimedia Press Co Ltd. All rights reserved.

关键词： bioactive ions bioceramics bone repair magnesium osteoconductivity

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How Torsion as Presented by De Sabbata and Sivaram in Erice 1990 Argument as Modified May Permit Cosmological Constant, and Baseline as to Dark Energy

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j.urnal of High Energy Physics, Gravitation and Cosmology 2024年第1期10卷 138-148页

作者： andrew Walcott Beckwith Physics Department Chongqing University Chongqing China

Based on the idea of cyclic conformal cosmology, we discuss how torsion may allow for a cosmological constant, which links the ideas given by Beckwith and QaZi 2023 to a presentation as far as Torsion as given by de Sabbata and Sir-varam, Erice 1990. The 1990 article claims that Torsion cancels Cosmological vacuum energy whereas our formulation leads to a left over cosmological constant 10-121 times vacuum energy. Meantime speculation as to how all this relates to black hole physics and speculation given by Corda which replaces traditional firewalls with a different formulation are included as that presentation by Corda uses the idea of a quantum number n, which ties into our own Cosmological constant presentation.

关键词： Inflation Gravitational Waves Penrose CCC

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Early anticoagulation in patients with stroke and atrial fibrillation is associated with fewer ischaemic lesions at 1 month: the ATTUNE study

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Stroke & Vascular Neurology 2024年第1期9卷 30-37,I0034页

作者： Angelos Sharobeam Longting Lin Christina Lam Carlos Garcia-Esperon Yash Gawarikar Ronak Patel Matthew Lee-Archer andrew Wong Michael Roizman Amanda Gilligan andrew Lee Kee Meng Tan Susan Day Christopher Levi Stephen M Davis Mark Parsons Bernard Yan Melbourne Brain Centre at Royal Melbourne Hospital ParkvilleVictoriaAustralia University of New South Wales South Western Sydney Clinical School LiverpoolNew South WalesAustralia Department of Neurology John Hunter HospitalNewcastleNew South WalesAustralia Department of Neurology Calvary Public HospitalCanberraAustralian Capital TerritoryAustralia Department of Neurology Northern Hospital EppingEppingVictoriaAustralia Department of Neurology Royal Brisbane and Women's HospitalHerstonQueenslandAustralia The University of Queensland School of Medicine HerstonQueenslandAustralia Neurosciences Clinical Institute Epworth HealthcareRichmondVirginiaAustralia Department of Neurology Austin HealthUniversity of MelbourneHeidelbergVictoriaAustralia Flinders University College of Medicine and Public Health AdelaideSouth AustraliaAustralia Department of Neurology Gold Coast University HospitalSouthportQueenslandAustralia The University of Sydney Northern Clinical School St LeonardsNew South WalesAustralia Department of Neurology and Neurophysiology Liverpool HospitalLiverpoolNew South WalesAustralia

Background The optimal time to commence anticoagulation in patients with atrial fibrillation(AF)after ischaemic stroke or transient ischaemic attack(TIA)is unclear,with guidelines differing in recommendations.A limitation of previous studies is the focus on clinically overt stroke,rather than radiologically obvious diffusion-weighted imaging ischaemic *** aimed to quantify silent ischaemic lesions and haemorrhages on MRI at 1month in patients commenced on early(5mL,regardless of anticoagulation *** Commencing anticoagulation<4days after stroke or TIA is associated with fewer ischaemic lesions at 1month in AF *** is no increased rate of haemorrhage with early *** results suggest that early anticoagulation after mild-to-moderate acute ischaemic stroke associated w

关键词： patients lesions ischaemic

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Generation of Eco-Friendly and Disease-Resistant Channel Catfish(Ictalurus punctatus)Harboring the Alligator Cathelicidin Gene via CRISPR/Cas9 Engineering

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Engineering 2024年第8期39卷 273-286页

作者： j.nhai Wang Baofeng Su De Xing Timothy j.Bruce Shangj.a Li Logan Bern Mei Shang andrew j.hnson Rhoda Mae C.Simora Michael Coogan Darshika U.Hettiarachchi Wenwen Wang Tasnuba Hasin j.cob Al-Armanazi Cuiyu Lu Rex A.Dunham School of Fisheries Aquacultureand Aquatic SciencesAuburn UniversityAuburnAL 36849USA

As a precise and versatile tool for genome manipulation,the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)platform holds promise for modifying fish traits of *** the aim of reducing transgene introgression and controlling reproduction,upscaled disease resistance and reproductive intervention in catfish species have been studied to lower the potential environmental risks of the introgression of escapees as transgenic *** advantage of the CRISPR/Cas9-mediated system,we succeeded in integrating the cathelicidin gene(As-Cath)from an alligator(Alligator sinensis)into the target luteinizing hormone(lh)locus of channel catfish(Ictalurus punctatus)using two delivery systems assisted by double-stranded DNA(dsDNA)and single-stranded oligodeoxynucleotides(ssODNs),*** this study,high knock in(KI)efficiency(22.38%,64/286)but low ontarget events was achieved using the ssODN strategy,whereas adopting a dsDNA as the donor template led to an efficient on-target KI(10.80%,23/213).The on-target KI of As-Cath was instrumental in establishing the lh knockout(LH^(–)_As-Cath^(+))catfish line,which displayed heightened disease resistance and reduced fecundity compared with the wild-type(WT)sibling ***,administration of human chorionic gonadotropin(HCG)and luteinizing hormone-releasing hormone analogue(LHRHa)can restore the reproduction of the transgenic fish ***,we replaced the lh gene with an alligator cathelicidin transgene and then administered hormone therapy to move towards complete reproductive control of diseaseresistant transgenic catfish in an environmentally responsible *** strategy not only effectively improves consumer-valued traits but also guards against unwanted introgression,providing a breakthrough in aquaculture genetics to confine fish reproduction and prevent the establishment of transgenic or domestic genotypes in the natural environment.

关键词： Genome editing ssODN dsDNA Antimicrobial peptide Reproductive confinement Aquaculture

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Electricity Generation from Heatwaves

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International j.urnal of Geosciences 2024年第5期15卷 449-457页

作者： Diandong Ren Mervyn j. Lynch School of Electrical Engineering Computing and Mathematical Sciences Curtin University Perth Australia Australian Sustainable Development Institute (ASDI) Perth Australia

We chose a definition of heatwaves (HWs) that has ~4-year recurrence frequency at world hot spots. We first examined the 1940-2022 HWs climatology and trends in lifespan, severity, spatial extent, and recurrence frequency. HWs are becoming more frequent and more severe for extratropical mid- and low-latitudes. To euphemize HWs, we here propose a novel clean energy-tapping concept that utilizes the available nano-technology, micro-meteorology knowledge of temperature distribution within/without buildings, and radiative properties of earth atmosphere. The key points for a practical electricity generation scheme from HWs are defogging, insulation, and minimizing the absorption of infrared downward radiation at the cold legs of the thermoelectric generators. One sample realization is presented which, through relay with existing photovoltaic devices, provides all-day electricity supply sufficient for providing air conditioning requirement for a residence (~2000-watt throughput). The provision of power to air conditioning systems, usually imposes a significant stress on traditional city power grids during heatwaves.

关键词： Heatwaves Climate Warming Clean Energy Generation by Thermoelectric Generator Ameliorate and Transcend Heatwaves Climate Warming Mitigation and Adaptation Thermoelectric Generator (TEG) IR Interaction with Periodically Arranged Nanostructures Optical Properties of Nano Fabricating Passive Clean Energy Tapping/Generation

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