Effect of torch angle on arc properties and weld pool shape in stationary GTAW

In this paper, a three dimensional numerical simulation is performed on a stationary arc to study the effect of torch angle in gas tungsten arc welding (GTAW) of SS304 stainless steel. A comparison has been made to investigate 90o and 70o torch angles and analyze the effect on arc and weld pool shape. Current density, heat flux and gas shear stress are calculated in the arc region and are used as input to the workpiece to determine the weld pool. Buoyancy and Marangoni shear also affect the weld pool shape and are taken into account. The computed and experimental results are observed symmetric for 90o torch angle. For 70o torch angle, current density and hence the heat flux due to electron contribution is found the maximum behind and heat flux due to conduction and convection is found the maximum ahead of the electrode tip in the welding direction. This makes the maximum of total heat flux symmetric along the arc center. Heat flux due to conduction and convection decreases as the torch angle decreases resulting in a shallow weld pool. The nonsymmetric “w” shaped weld pool is developed by the combined effect of the gas shear and Marangoni convection. It is found that for 70o torch angle, the weld pool becomes non-symmetric, shallow and wide ahead of the electrode tip in the welding direction. The numerical weld pool shapes are verified through experiments

Hepatitis E virus ORF2 protein over-expressed by baculovirus in hepatoma cells, efficiently encapsidates and transmits the viral RNA to naïve cells

A recombinant baculovirus(vBacORF2) that expressed the full-length ORF2 capsid protein of a genotype 1 strain of hepatitis E virus(HEV) was constructed. Transduction of S10-3 human hepatoma cells with this baculovirus led to large amounts of ORF2 protein production in ~50% of the cells as determined by immune fluorescence microscopy. The majority of the ORF2 protein detected by Western blot was 72 kDa, the size expected for the full-length protein. To determine if the exogenously-supplied ORF2 protein could transencapsidate viral genomes, S10-3 cell cultures that had been transfected the previous day with an HEV replicon of genotype 1 that contained the gene for green fluorescent protein(GFP), in place of that for ORF2 protein, were transduced with the vBacORF2 virus. Cell lysates were prepared 5 days later and tested for the ability to deliver the GFP gene to HepG2/C3A cells, another human hepatoma cell line. FACS analysis indicated that lysates from cell cultures receiving only the GFP replicon were incapable of introducing the replicon into the HepG2/C3A cells whereas ~2% of the HepG2/C3A cells that received lysate from cultures that had received both the replicon and the baculovirus produced GFP. Therefore, the baculovirus-expressed ORF2 protein was able to trans-encapsidate the viral replicon and form a particle that could infect naïve HepG2/C3A cells. This ex vivo RNA packaging system should be useful for studying many aspects of HEV molecular biology

(R)-Doxylaminium (R,R)-tartrate

In the title compound (systematic name: (R)-dimeth­yl{2-[1-phenyl-1-(pyridin-2-yl)eth­oxy]eth­yl}aza­nium (R,R)-3-carb­oxy-2,3-dihy­droxy­propano­ate), C17H23N2O+·C4H5O6 −, the doxylaminium cation is protonated at the N atom. The tartrate monoanions are linked by short, almost linear O—H⋯O hydrogen bonds into chains extended along [100]. These chains are inter­linked by anion–pyridine O—H⋯N hydrogen bonds into a two-dimensional grid structure. WeakC—H⋯O inter­actions also play a role in the crystal packing. An intra­molecular hy­droxy–carboxyl­ate O—H⋯O hydrogen bond influences the conformation of the anion: the hydrogen-bonded fragment is almost planar, the maximum deviation from the mean plane being 0.059 (14) Å. In the cation, the aromatic rings are almost perpendicular [dihedral angle = 84.94 (8)°] and the conformation of the O—C—C—N chain is gauche(−), the dihedral angle is −76.6 (2)°. The absolute configuration was assigned on the basis of known chirality of the parent compound

Intermittency in Two-Dimensional Turbulence with Drag

We consider the enstrophy cascade in forced two-dimensional turbulence with a linear drag force. In the presence of linear drag, the energy wavenumber spectrum drops with a power law faster than in the case without drag, and the vorticity field becomes intermittent, as shown by the anomalous scaling of the vorticity structure functions. Using a previous theory, we compare numerical simulation results with predictions for the power law exponent of the energy wavenumber spectrum and the scaling exponents of the vorticity structure functions $\zeta_{2q}$ obtained in terms of the distribution of finite time Lyapunov exponents. We also study, both by numerical experiment and theoretical analysis, the multifractal structure of the viscous enstrophy dissipation in terms of its R\'{e}nyi dimension spectrum $D_q$ and singularity spectrum $f(\alpha)$. We derive a relation between $D_q$ and $\zeta_{2q}$, and discuss its relevance to a version of the refined similarity hypothesis. In addition, we obtain and compare theoretically and numerically derived results for the dependence on separation $r$ of the probability distribution of \delta_{\V{r}}\omega, the difference between the vorticity at two points separated by a distance $r$. Our numerical simulations are done on a $4096 \times 4096$ grid.Comment: 18 pages, 17 figure

Multiplex-PCR protocol development for rapid screening of white spot syndrome virus (WSSV) in shrimp

This study was aimed to develop a faster single step multiplex PCR protocol for the simultaneous detection of white spot syndrome virus (WSSV) with its host (i.e. shrimp) as internal positive control. To do so, four combinations of primer were tested (I. 16S rRNA+Lo F1R1; II. 16S rRNA+Lo F2R2; III. 16S rRNA+Lo F1R2; IV. 16S rRNA+Lo F2R1) which were selected based on two pairs of WSSV specific primer (Lo F1R1 and Lo F2R2) and one pair of shrimp specific primer (16S rRNA). DNA extracted from WSSV infected shrimp were amplified by PCR in a single tube using each of the primer combinations and the thermal cycling conditions as well as reagent compositions were optimized. All the primer combinations yielded their expected band sizes with stronger band resolution intensity that indicated the development of four multiplex PCR protocols. The developed multiplex protocols reduced the chance of cross contamination and these were found to be faster, single step and unique with less effort and resource use. Considering sensitivity and specificity, among the protocols, we suggested the protocols based on 16S rRNA+Lo F1R1 and/or 16S rRNA+Lo F2R2 primer combinations for rapid and routine screening of WSSV in shrimp PL, juvenile and adult

Mathematical modeling on the transmission of COVID-19 and its reproduction numbers in SAARC countries

In the middle of December 2019, a virus known as coronavirus (COVID-19) generated by severe acute respiratory syndrome corona virus 2 (SARC-CoV-2) was first detected in Wuhan, Hubei Province, China. As of the 9th of March, 2022, spread to over 212 countries, causing 429 million confirmed cases and 6 million people to lose their lives worldwide. In developing countries like the South Asian area, alarming dynamic variations in the pattern of confirmed cases and death tolls were displayed. During epidemics, accurate assessment of the characteristics that characterize infectious disease transmission is critical for optimizing control actions, planning, and adapting public health interventions. The reproductive number, or the typical number of secondary cases caused by an infected individual, can be employed to determine transmissibility. Several statistical and mathematical techniques have been presented to calculate across the duration of an epidemic. A technique is provided for calculating epidemic reproduction numbers. It is a MATLAB version of the EpiEstim package's R function estimate R, version 2.2-3. in the South Asian Association for Regional Cooperation (SAARC) countries. The three methodologies supported are 'parametric SI,' 'non-parametric SI,' and 'uncertain SI.' The present study indicated that the highest reproduction number was 12.123 and 11.861 on 5th and 14th March 2020 in India and Sri_Lanka, whereas the lowest reproduction number was the lowest was 0.300 and 0.315 in Sri_Lanka and India. The Maximum and minimum reproductive number of Bangladesh was 3.752 and 0.725. In this study, we have tried to point out the worst, best and current situation of SAARC countries

In-vitro Cytotoxicity and In-silico Insights of the Multi-target Anticancer Candidates from Haplophyllum tuberculatum

This study aimed to investigate the anticancer activity of Haplophyllum tuberculatum(Forsk.) aerial parts ethanol extract and fractions and reveal the potential anticancer targets, binding modes, pharmacokinetics, and toxicity properties of its phytoconstituents. MTT assay was used to investigate the anticancer activity. TargetNet, ChemProt version 2.0, and CLC-Pred web servers were used for virtual screening, and Cresset Flare software was used for molecular docking with the 26 predicted targets. Moreover, pkCSM, swiss ADME, and eMolTox web servers were used to predict pharmacokinetics and safety. Ethanolic extracts of H. tuberculatum on HepG2 and HeLa cell lines showed promising activities with IC50 values 54.12 and 48.1 µg/mL, respectively. Further, ethyl acetate fraction showed the highest cytotoxicity on HepG2 and HeLa cell lines with IC50 values 41.7 and 52.31 µg/mL. Of 70 compounds screened virtually, polygamain, justicidin A, justicidin B, haplotubine, kusunokinin, and flindersine were predicted as safe anticancer drugs candidates. They showed the highest binding scores with targets involved in cell growth, proliferation, survival, migration, tumor suppression, induction of apoptosis, metastasis, and drug resistance. Our findings revealed the potency of H. tuberculatum as a source of anticancer candidates that further studies should support

A dimer of 4-(4-methoxyphenyl)-1,2,3,5-diselenadiazole

Sherpa Romeo green journalThe analysis of the title compound, C8H7N2OSe2, shows that its crystals are composed of weakly linked dimers, with intramolecular Se--Se distances of 2.343(3) and 2.345 (2)A,, intermolecular Se-.-Se distances of 3.193(3) and 3.316 (3) /k, and lateral Se...Se interactions of 3.514 (2) and 3.579 (3) A,.Ye