1,215 research outputs found
Feasibility study of vacuum technology integrated fused deposition modeling to reduce staircase effect
Fused deposition modeling (FDM) is currently one of the most used AM technologies and has been around in various industries since its tremendous offering. Most semi-molten layered thermoplastic surface often uneven, which lead to rough and poor surface finish. The FDM process involves temperature gradient since the material extrude was in a semi-molten state. The thermal stresses present and affect the surface quality. This paper proposes an idea of using vacuum technology to reduce the âstaircase effectâ parts printed. The FDM machine remains in a rectangular acrylic chamber, an oil-flooded-vacuum pump connected will absorb the air inside the chamber until desire pressure while printing object. Mitutoyo SJ-301 portable surface roughness tester and optical microscope used to analyze the quality of surface finish. Result reveal with vacuum technology, improve 9% from normal print.Keywords: fused deposition modeling; simulation; vacuum technology; surface finis
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Preparation of high purity plutonium oxide for radiochemistry instrument calibration standards and working standards
Due to the lack of suitable high level National Institute of Standards and Technology (NIST) traceable plutonium solution standards from the NIST or commercial vendors, the CST-8 Radiochemistry team at Los Alamos National Laboratory (LANL) has prepared instrument calibration standards and working standards from a well-characterized plutonium oxide. All the aliquoting steps were performed gravimetrically. When a {sup 241}Am standardized solution obtained from a commercial vendor was compared to these calibration solutions, the results agreed to within 0.04% for the total alpha activity. The aliquots of the plutonium standard solutions and dilutions were sealed in glass ampules for long term storage
Vacuum fused deposition modelling system to improve tensile strength of 3D printed parts
Functional parts require high a level of strength and the current Fused Deposition Modelling (FDM) cannot be fully utilized as the end used parts. The poor mechanical strength is caused by the incomplete layer bonding during the printing process. In the printing process, the interlayer bonding is made too quick thus the layers are not fully fused together causing the reduced tensile strength. This paper presents a possible solution to this problem by incorporating vacuum technology in FDM system to improve tensile strength of 3D printed specimens. In this study, a desktop FDM machine was placed and operated inside a low pressure vacuum chamber. The results obtained show an improvement of 12.83 % of tensile strength compared to the standard specimen. This paper concludes that the low pressure environment is useful in reducing the heat loss due to convection of air, hence directly improves the specimenâs tensile strength.Keywords: additive manufacturing; fused deposition modelling; vacuum system; mechanical strength
Multipartite Entanglement and Quantum State Exchange
We investigate multipartite entanglement in relation to the theoretical
process of quantum state exchange. In particular, we consider such entanglement
for a certain pure state involving two groups of N trapped atoms. The state,
which can be produced via quantum state exchange, is analogous to the
steady-state intracavity state of the subthreshold optical nondegenerate
parametric amplifier. We show that, first, it possesses some 2N-way
entanglement. Second, we place a lower bound on the amount of such entanglement
in the state using a novel measure called the entanglement of minimum bipartite
entropy.Comment: 12 pages, 4 figure
COVID-19 and liver disease: mechanistic and clinical perspectives
Our understanding of the hepatic consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its resultant coronavirus disease 2019 (COVID-19) has evolved rapidly since the onset of the pandemic. In this Review, we discuss the hepatotropism of SARS-CoV-2, including the differential expression of viral receptors on liver cell types, and we describe the liver histology features present in patients with COVID-19. We also provide an overview of the pattern and relevance of abnormal liver biochemistry during COVID-19 and present the possible underlying direct and indirect mechanisms for liver injury. Furthermore, large international cohorts have been able to characterize the disease course of COVID-19 in patients with pre-existing chronic liver disease. Patients with cirrhosis have particularly high rates of hepatic decompensation and death following SARS-CoV-2 infection and we outline hypotheses to explain these findings, including the possible role of cirrhosis-associated immune dysfunction. This finding contrasts with outcome data in pharmacologically immunosuppressed patients after liver transplantation who seem to have comparatively better outcomes from COVID-19 than those with advanced liver disease. Finally, we discuss the approach to SARS-CoV-2 vaccination in patients with cirrhosis and after liver transplantation and predict how changes in social behaviours and clinical care pathways during the pandemic might lead to increased liver disease incidence and severity. © 2021, Springer Nature Limited
PO-0698: Clinical outcomes of 4D CBCT-guided stereotactic body radiotherapy for inoperable hepatocellular carcinomas
Poster: Clinical track: Gastrointestinal tumours (upper and lower GI)published_or_final_version3rd ESTRO Forum, Barcelona, Spain, 24-28 April 2015. In Radiotherapy & Oncology, 2015, v. 115, p. S342-S34
Semirigid Geometry
We provide an intrinsic description of -super \RS s and -\SR\
surfaces. Semirigid surfaces occur naturally in the description of topological
gravity as well as topological supergravity. We show that such surfaces are
obtained by an integrable reduction of the structure group of a complex
supermanifold. We also discuss the \s moduli spaces of -\SR\ surfaces and
their relation to the moduli spaces of -\s\ \RS s.Comment: 29p
Quantitative trait loci for bone traits segregating independently of those for growth in an F-2 broiler X layer cross
An F broiler-layer cross was phenotyped for 18 skeletal traits at 6, 7 and 9 weeks of age and genotyped with 120 microsatellite markers. Interval mapping identified 61 suggestive and significant QTL on 16 of the 25 linkage groups for 16 traits. Thirty-six additional QTL were identified when the assumption that QTL were fixed in the grandparent lines was relaxed. QTL with large effects on the lengths of the tarsometatarsus, tibia and femur, and the weights of the tibia and femur were identified on GGA4 between 217 and 249 cM. Six QTL for skeletal traits were identified that did not co-locate with genome wide significant QTL for body weight and two body weight QTL did not coincide with skeletal trait QTL. Significant evidence of imprinting was found in ten of the QTL and QTL x sex interactions were identified for 22 traits. Six alleles from the broiler line for weight- and size-related skeletal QTL were positive. Negative alleles for bone quality traits such as tibial dyschondroplasia, leg bowing and tibia twisting generally originated from the layer line suggesting that the allele inherited from the broiler is more protective than the allele originating from the layer
Randomised clinical non-inferiority trial of breathing-based meditation and cognitive processing therapy for symptoms of post-traumatic stress disorder in military veterans
Objective Test whether Sudarshan Kriya Yoga (SKY) was non-inferior to cognitive processing therapy (CPT) for treating symptoms of post-traumatic stress disorder (PTSD) among veterans via a parallel randomised controlled non-inferiority trial.
Setting Outpatient Veterans Affairs healthcare centre.
Participants 85 veterans (75 men, 61% white, mean age 56.9) with symptoms of PTSD participated between October 2015 and March 2020: 59 participants completed the study.
Interventions SKY emphasises breathing routines and was delivered in group format in a 15-hour workshop followed by two 1-hour sessions per week for 5 weeks. CPT is an individual psychotherapy which emphasises shifting cognitive appraisals and was delivered in two 1-hour sessions per week for 6 weeks.
Measures The primary outcome measure was the PTSD Checklist-Civilian Version (PCL-C). The secondary measures were the Beck Depression Inventory-II (BDI-II) and Positive and Negative Affect Scale (PANAS).
Results Mean PCL-C at baseline was 56.5 (±12.6). Intent-to-treat analyses showed that PCL-C scores were reduced at 6âweeks (end of treatment) relative to baseline (SKY, â5.6, d=0.41, n=41: CPT, â6.8, d=0.58, n=44). The between-treatment difference in change scores was within the non-inferiority margin of 10 points (â1.2, 95%âCI â5.7 to 3.3), suggesting SKY was not inferior to CPT. SKY was also non-inferior at 1-month (CPTâSKY: â2.1, 95%âCI â6.9 to 2.8) and 1-year (CPTâSKY: â1.8, 95%âCI â6.6 to 2.9) assessments. SKY was also non-inferior to CPT on the BDI-II and PANAS at end of treatment and 1âmonth, but SKY was inferior to CPT on both BDI-II and PANAS at 1âyear. Dropout rates were similar (SKY, 27%, CPT, 34%: OR=1.36, 95%âCI 0.51 to 3.62, p=0.54).
Conclusions SKY may be non-inferior to CPT for treating symptoms of PTSD and merits further consideration as a treatment for PTSD
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