Navier-Stokes Flow Field Analysis of Compressible Flow in a Pressure Relief Valve

The present study was motivated to analyze the complex flow field involving gaseous oxygen (GOX) flow in a relief valve (RV). The 9391 RV, pictured in Figure 1, was combined with the pilot valve to regulate the actuation pressure of the main valve system. During a high-pressure flow test at Marshall Space Flight Center (MSFC) the valve system developed a resonance chatter, which destroyed most of the valve body. Figures 2-4 show the valve body before and after accident. It was understood that the subject RV has never been operated at 5500 psia. In order to fully understand the flow behavior in the RV, a computational fluid dynamics (CFD) analysis is carried out to investigate the side load across the piston sleeve and the erosion patterns resulting from flow distribution around piston/nozzle interface

Degradation of Metaldehyde in Aqueous Solution by Nano-Sized Photocatalysts and Granular Activated Carbon

Metaldehyde has been detected in drinking water system in relatively high concentration exceeding European water quality standard. In order to address this problem, the aim of this project was to treat metaldehyde aqueous solution by advanced oxidation processes (AOPs) and granular activated carbon (GAC) column. Ten novel materials were tested for degradation rates of metaldehyde under ultraviolet light irradiation (UVC). For treatment of 1 mg/L metaldehyde solution by AOPs, the highest degradation rate is 16.59% under UVC light with the aid of nitrogen doped titanium dioxide coated graphene (NTiO2/Gr). Furthermore, 0.5 mg/L is the optimal concentration for degradation of metaldehyde with N–TiO2/Gr under UVC light. Apart from that, the lifetime of GAC column could be elongated on condition that metaldehyde has been treated by AOPs previously. Hence, combination of AOPs and GAC column is promising in treating water containing metaldehyde

MAX 4 and MAX 5 CMB anisotropy measurement constraints on open and flat-Lambda CDM cosmogonies

We account for experimental and observational uncertainties in likelihood analyses of cosmic microwave background (CMB) anisotropy data from the MAX 4 and MAX 5 experiments. These analyses use CMB anisotropy spectra predicted in open and spatially-flat Lambda cold dark matter cosmogonies. Amongst the models considered, the combined MAX data set is most consistent with the CMB anisotropy shape in Omega_0 ~ 0.1-0.2 open models and less so with that in old (t_0 >~ 15 - 16 Gyr, i.e., low h), high baryon density (Omega_B >~ 0.0175/h^2), low density (Omega_0 ~ 0.2 - 0.4), flat-Lambda models. The MAX data alone do not rule out any of the models we consider at the 2-sigma level. Model normalizations deduced from the combined MAX data are consistent with those drawn from the UCSB South Pole 1994 data, except for the flat bandpower model where MAX favours a higher normalization. The combined MAX data normalization for open models with Omega_0 ~ 0.1-0.2 is higher than the upper 2-sigma value of the DMR normalization. The combined MAX data normalization for old (low h), high baryon density, low-density flat-Lambda models is below the lower 2-sigma value of the DMR normalization. Open models with Omega_0 ~ 0.4-0.5 are not far from the shape most favoured by the MAX data, and for these models the MAX and DMR normalizations overlap. The MAX and DMR normalizations also overlap for Omega_0 = 1 and some higher h, lower Omega_B, low-density flat-Lambda models.Comment: Latex, 37 pages, uses aasms4 styl

Effect of Pt vacancies on magnetotransport of Weyl semimetal candidate GdPtSb epitaxial films

We examine the effects of Pt vacancies on the magnetotransport properties of Weyl semimetal candidate GdPtSb films, grown by molecular beam epitaxy on c-plane sapphire. Rutherford backscattering spectrometry (RBS) and x-ray diffraction measurements suggest that phase pure GdPt$_{x}$Sb films can accommodate up to $15\%$ Pt vacancies ($x=0.85$), which act as acceptors as measured by Hall effect. Two classes of electrical transport behavior are observed. Pt-deficient films display a metallic temperature dependent resistivity (d$\rho$/dT$>$0). The longitudinal magnetoresistance (LMR, magnetic field $\mathbf{B}$ parallel to electric field $\mathbf{E}$) is more negative than transverse magnetoresistance (TMR, $\mathbf{B} \perp \mathbf{E}$), consistent with the expected chiral anomaly for a Weyl semimetal. The combination of Pt-vacancy disorder and doping away from the expected Weyl nodes; however, suggests conductivity fluctuations may explain the negative LMR rather than chiral anomaly. Samples closer to stoichiometry display the opposite behavior: semiconductor-like resistivity (d$\rho$/dT$<$0) and more negative transverse magnetoresistance than longitudinal magnetoresistance. Hysteresis and other nonlinearities in the low field Hall effect and magnetoresistance suggest that spin disorder scattering, and possible topological Hall effect, may dominate the near stoichiometric samples. Our findings highlight the complications of transport-based identification of Weyl nodes, but point to possible topological spin textures in GdPtSb

Detection of Recent HIV-1 Infection Using a New Limiting-Antigen Avidity Assay: Potential for HIV-1 Incidence Estimates and Avidity Maturation Studies

Background: Accurate and reliable laboratory methods are needed for estimation of HIV-1 incidence to identify the highrisk populations and target and monitor prevention efforts. We previously described a single-well limiting-antigen avidity enzyme immunoassay (LAg-Avidity EIA) to detect recent HIV-1 infection. Methods: We describe here further optimization and characterization of LAg-Avidity EIA, comparing it to the BED assay and a two-well avidity-index (AI) EIA. Specimen sets included longitudinal sera (n = 393), collected from 89 seroconverting individuals from 4 cohorts representing 4 HIV-1 subtypes, and sera from AIDS patients (n = 488) with or without TB coinfections from 3 different cohorts. Ninety seven HIV-1 positive specimens were purchased commercially. The BED assay, LAg-Avidity EIA, AI-EIA and HIV serology were performed, as needed. Results: Monitoring quality control specimens indicated high reproducibility of the LAg-Avidity EIA with coefficient of variation of,10 % in the dynamic range. The LAg-Avidity EIA has an overall mean duration of recency (v) of 141 days (95% CI 119–160) at normalized optical density (ODn) cutoff of 1.0, with similar v in different HIV-1 subtypes and populations (132 to 143 days). Antibody avidity kinetics were similar among individuals and subtypes by both the LAg-Avidity EIA and AI-EIA compared to the HIV-IgG levels measured by the BED assay. The false recent rate among individuals with AIDS was 0.2% with the LAg-Avidity EIA, compared to 2.9 % with the BED assay. Western blot profiles of specimens with increasing avidit

Mutagenesis and digital image analysis of mutants for quality attributes of native Cynodon dactylon

The ability to capture information of turf grass in situ makes digital camera based image analysis, a viable tool to quantify turf grass (Cynodon dactylon Pers.) in field experiments. In addition to colour quantification, digital image analysis has been used successfully to quantify percentage turf grass cover and has also been proved to be useful in quantifying turf parameters such as weed infestation, disease incidence, herbicide toxicity, leaf area and recovery from injury. Colour is one of the major criteria used to evaluate the quality of turf and lawn. To generate variability in Bermuda grass to select genotypes responsive to low management, gamma-ray irradiation was used for induction of dwarfness and other quality attributes. Five dwarf mutant lines (DFR 440, DFR-C-444, DFR-C-445, DFR-C 446 and DFR-C-448) were isolated. In the present study, camera and image analysis technique is applied to measure turf colour by its reflectance in the HSB colour scale. The data depicts that the dwarf mutant lines had better quality of lower canopy height, shorter internodes and shorter leaves than the parent. It is demonstrated that image analysis is a suitable non-destructive tool to assess turf grass colour in a reproducible and calibrated manner, over a wide span of structural and colour attributes of turf grass

Blame, Symbolic Stigma and HIV Misconceptions are Associated with Support for Coercive Measures in Urban India

This study was designed to examine the prevalence of stigma and its underlying factors in two large Indian cities. Cross-sectional interview data were collected from 1,076 non-HIV patients in multiple healthcare settings in Mumbai and Bengaluru, India. The vast majority of participants supported mandatory testing for marginalized groups and coercive family policies for PLHA, stating that they “deserved” their infections and “didn’t care” about infecting others. Most participants did not want to be treated at the same clinic or use the same utensils as PLHA and transmission misconceptions were common. Multiple linear regression showed that blame, transmission misconceptions, symbolic stigma and negative feelings toward PLHA were significantly associated with both stigma and discrimination. The results indicate an urgent need for continued stigma reduction efforts to reduce the suffering of PLHA and barriers to prevention and treatment. Given the high levels of blame and endorsement of coercive policies, it is crucial that such programs are shaped within a human rights framework

In vitro assembly of Ebola virus nucleocapsid-like complex expressed in E. coli

Ebola virus (EBOV) harbors an RNA genome encapsidated by nucleoprotein (NP) along with other viral proteins to form a nucleocapsid complex. Previous Cryo-eletron tomography and biochemical studies have shown the helical structure of EBOV nucleocapsid at nanometer resolution and the first 450 amino-acid of NP (NPΔ451–739) alone is capable of forming a helical nucleocapsid-like complex (NLC). However, the structural basis for NP-NP interaction and the dynamic procedure of the nucleocapsid assembly is yet poorly understood. In this work, we, by using an E. coli expression system, captured a series of images of NPΔ451–739 conformers at different stages of NLC assembly by negative-stain electron microscopy, which allowed us to picture the dynamic procedure of EBOV nucleocapsid assembly. Along with further biochemical studies, we showed the assembly of NLC is salt-sensitive, and also established an indispensible role of RNA in this process. We propose the diverse modes of NLC elongation might be the key determinants shaping the plasticity of EBOV virions. Our findings provide a new model for characterizing the self-oligomerization of viral nucleoproteins and studying the dynamic assembly process of viral nucleocapsid in vitro