A study on hydroentangling waterjets and their impact forces

We study the possibility of obtaining an intense fluctuating force during the steady-state operation of a waterjet. In this paper, characteristics of waterjets in the so-called first wind-induced breakup regime are briefly explained and the impaction between such waterjets and a smooth flat plate is discussed. We consider these waterjets to consist of three different regions: (1) a continuous portion, (2) a discrete portion (a stream of drops) and (3) a spray region. Using fluid dynamics simulation we obtain an impulsive impact force for the discrete portion of these waterjets. The peak of this impulsive impact force is found to be 3.5–4 times greater than that of the continuous portion. We validate our simulations by conducting an experiment for a stream of large low-speed drops. The impact force of these drops is in good agreement with that of simulation.     

Calculating mass transfer from vertical wet fabrics using a free convection heat transfer correlation

In this note, the evaporation rate from a vertical wet fabric sheet is calculated using a free convection heat transfer correlation. Chilton–Colburn analogy is used to derive a mass transfer correlation from a heat transfer correlation proposed by Churchill and Chu for free convection from a vertical isothermal plate. The mass transfer rate obtained from this expression has shown excellent agreement with experimental data.     

Modeling motion-induced fluid release from partially saturated fibrous media onto surfaces with different hydrophilicity

Modeling the rate of fluid release from moving partially saturated nonwoven sheets in contact with a solid surface is a challenge, as the release rate depends on many parameters, some of which are difficult to quantify. In this paper, we report on a diffusion-controlled boundary treatment which we have developed to simulate fluid release from partially saturated porous materials onto surfaces with different hydrophilicy. The new boundary treatment considers the solid impermeable surface as a fictitious porous layer with a known fluid diffusive coefficient. Motion of the porous sheet on the surface is incorporated in the simulations by periodically resetting the saturation of the fictitious layer equal to zero, with a period obtained from the sheet’s speed of motion. Fluid transport inside the fibrous sheets is calculated by solving Richards’ equation of two-phase flows in porous media. Our numerical simulations are accompanied with experimental data obtained using a custom-made test rig for the release of liquid from partially saturated media at different speeds. It is demonstrated that the novel mathematical formulations presented here can correctly predict the rate of fluid release from moving fibrous sheets onto solid surfaces with different hydrophilicity as a function of time.     

Functional Expression of <Emphasis Type="Italic">Bacillus anthracis</Emphasis> Protective Antigen in <Emphasis Type="Italic">E. coli</Emphasis>

The protective antigen (PA) of Bacillus anthracis is a potent immunogen and an important candidate vaccine. In addition, it is used in monitoring systems like enzyme-linked immunosorbent assay to assess antibodies against PA in immunized subjects. The low level of PA production in B. anthracis and the difficulty of separating it from other bacterial components have made the researchers do different studies with the aim of producing recombinant PA (rPA). In this study, to produce rPA as a recombinant protein vaccine, the partial sequence of protective antigen of B. anthracis, amino acids 175–764, as a potent immunogenic target was inserted in pET21b(+). This is a prokaryotic plasmid that carries an N-terminal T7.tag sequence. The integrity of constructed plasmid was confirmed using restriction enzyme mapping. rPA was expressed after induction with isopropyl β-d-1-thiogalactopyranoside in Escherichia coli BL21. Purification of rPA was done with an affinity system using anti T7.tag antibody. Electrophoresis and Western blotting confirmed the specificity of the expressed protein. BALB/c mice were immunized with obtained PA protein and evaluation of specific immunoglobulin G antibodies against PA in sera using Western blotting method and showed that rPA is immunogenic. The challenge of immunized mice with virulent strain of B. anthracis showed that rPA is functional to protect against pathogenic strain.     

Extension of elliptic curves on Krasner hyperfields

The aim of the article is to initiate a new study in the framework of algebraic hyperfields, with an applicative impact in cryptography. First we define the notions of generalized Weierstrass equation and elliptic hypercurve on Krasner hyperfields, as a generalization of the notion of elliptic curve on fields. Then we investigate properties of the hypergroups derived from elliptic hypercurves and of the associated H_v-groups. Finally, we present a class of canonical hypergroups, which can be used as an alphabet in a special cryptographic system.     

Equilibrium profiles for RF-plasma sources with ponderomotiveforces

An analysis is given of the influence of the electron ponderomotive force on the equilibrium plasma profiles of partially ionized, radio frequency discharge sources, The ponderomotive force can be written as a gradient of a potential varying with the square of the RF field in the plasma and is largest for electrons, The impact of this electron ponderomotive force on density and electrostatic potential profiles is demonstrated using a one-dimensional analytic model with supporting numerical solutions and a two dimensional fluid simulation. For nearly collisionless plasmas the ponderomotive force is valid when ω_ce^h/ω<1 where ω_ce ^h is the electron cyclotron frequency due to the RF magnetic field and ω is the RF driving frequency, In processing plasmas with parameters that satisfy this validity criteria, the equilibrium density profiles are weakly modified, For nearly collisionless processing plasmas with parameters such that ω_ce^h /ω>1, the ponderomotive force, is modified by other nonlinear force terms that need to be evaluated     

The thermal rearrangement of thiabenzenes to their isomeric thiopyrans

The rates of rearrangement in 1-phenyl-2,4,6-tris(p-methoxyphenyl)thiabenzene (4) and 1-(p-tri-fluoromethylphenyl)-2,4,6-triphenylthiabenzene (5) were determined and a crossover experiment was carried out with a mixture of these thiabenzenes. The possibility of 2,4-migrations in the thiopyran system under the reaction conditions was also studied by examining two samples of thiopyrans. The results indicate an intramolecular rearrangement which involves a 1,2- and 1,4-migration of 5-aryl groups in thiabenzenes.     

Synthesis of New Nitro‐Furan and Nitro‐Thiophene Derivatives from (Chlorocarbonyl) Phenyl Ketene

Nitro‐aromatic compounds are used in many human enteropathogenic bacterial infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram‐negative intestial Enterobacteriaceae. The interesting properties of these compounds encourage us to synthesis some new of these compounds by a simple route, starting from (Chlorocarbonyl) phenyl ketene.