A Note on the Laminar Heat Transfer in an Annulus

An exact solution for the fluid temperature due to forced convective heat transfer in an annulus is obtained as a solution of the eigen value problem

Synthesis and in vitro microbiological evaluation of 5-acetyl-4-aryl-6-methyl-3,4- dihydropyrimidin-2(1H)-thiones using calcium fluoride as catalyst

Abstract Seven 5-acetyl-4-aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-thiones 10-16 are prepared by a one-pot cyclocondensation reaction of acetylacetone (1), thiourea (2) and aldehyde (3-9) in ethanol using calcium fluoride as the catalyst is described. All the compounds are screened for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi and antifungal activity against Candida albicans, Aspergillus flavus, Rhizopus and Mucor. Ciprofloxacin is used for the standard for antibacterial and Amphotericin B is used for the standard for antifungal studies. Compounds 12-15 exhibited excellent in vitro antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Whereas the same set of compounds exerted potent in vitro antifungal activity against Candida albicans and Aspergillus flavus

Theoretical calculations of the primary defects induced by pions and protons in SiC

In the present work, the bulk degradation of SiC in hadron (pion and proton) fields, in the energy range between 100 MeV and 10 GeV, is characterised theoretically by means of the concentration of primary defects per unit fluence. The results are compared to the similar ones corresponding to diamond, silicon and GaAs.Comment: 9 pages, 2 figures, in press to Nuclear Instruments and Methods in Physics Research A v2 - modified title, and major revision

Exact norm-conserving stochastic time-dependent Hartree-Fock

We derive an exact single-body decomposition of the time-dependent Schroedinger equation for N pairwise-interacting fermions. Each fermion obeys a stochastic time-dependent norm-preserving wave equation. As a first test of the method we calculate the low energy spectrum of Helium. An extension of the method to bosons is outlined.Comment: 21 pages, 3 figures, LaTeX fil

Finite Element Analysis and Machine Learning Guided Design of Carbon Fiber Organosheet-based Battery Enclosures for Crashworthiness

Carbon fiber composite can be a potential candidate for replacing metal-based battery enclosures of current electric vehicles (E.V.s) owing to its better strength-to-weight ratio and corrosion resistance. However, the strength of carbon fiber-based structures depends on several parameters that should be carefully chosen. In this work, we implemented high throughput finite element analysis (FEA) based thermoforming simulation to virtually manufacture the battery enclosure using different design and processing parameters. Subsequently, we performed virtual crash simulations to mimic a side pole crash to evaluate the crashworthiness of the battery enclosures. This high throughput crash simulation dataset was utilized to build predictive models to understand the crashworthiness of an unknown set. Our machine learning (ML) models showed excellent performance (R2 > 0.97) in predicting the crashworthiness metrics, i.e., crush load efficiency, absorbed energy, intrusion, and maximum deceleration during a crash. We believe that this FEA-ML work framework will be helpful in down select process parameters for carbon fiber-based component design and can be transferrable to other manufacturing technologies

MHz Unidirectional Rotation of Molecular Rotary Motors

A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions

Statistical approach for unpolarized fragmentation functions for the octet baryons

A statistical model for the parton distributions in the nucleon has proven its efficiency in the analysis of deep inelastic scattering data, so we propose to extend this approach to the description of unpolarized fragmentation functions for the octet baryons. The characteristics of the model are determined by using some data on the inclusive production of proton and $\Lambda$ in unpolarized deep inelastic scattering and a next-to-leading analysis of the available experimental data on the production of unpolarized octet baryons in $e^+e^-$ annihilation. Our results show that both parton distributions and fragmentation functions are compatible with the statistical approach, in terms of a few free parameters, whose interpretation will be discussed.Comment: 14 pages, 7 eps figures, to appear in Phys. Rev.

2-r-(4-Chloro­phen­yl)-6-c-phenyl-3,4,5,6-tetra­hydro-2H-thio­pyran-4-one 1-oxide

The thio­pyran unit of the title mol­ecule, C17H15ClO2S, is in chair form. A crystallographic mirror plane bis­ects the mol­ecule, passing through the O=S and the opposite C=O atoms of the central ring, with statistical disorder of the Cl atom. The geometry around the S atom is tetra­hedral and the carbonyl C is planar. The 4-chloro­phenyl group at the 2 position and the phenyl ring at the 6 position have equatorial orientations. Inter­molecular C—H⋯O and C—H⋯Cl hydrogen bonds are found in the crystal structure. In addition, there is a short O⋯C inter­molecular contact [2.970 (5) Å]

Review of Joining Various Materials by FSW Process and Applications

Welding is necessary in industries like light and heavy-duty manufacturing, construction, automotive, aerospace, maintenance, repair works, etc. Friction stir welding (FSW) is a recently created welding technique that is employed with a non-consumable pin in all of the above-mentioned production areas. The cross-sectional size and shapes of the pin are also showing a great impact on the properties of the joints. This review article begins with the history of welding methods and it covers the topics of welding evolution, principle, joining of similar and dissimilar materials using FSW, applications and defects, as well as the various process factors in managing the qualities of the welded joint. The necessity of FSW is inevitable as it shows a good response of the mechanical properties with solid state temperature. It is a versatile welding process that has the capacity to join numerous materials, beginning with aluminium alloys and moving on to magnesium alloys, steel, composites, polymers, and dissimilar metals combinations