An approach for unipolar corona discharge in N2/O2 gas mixture by considering townsend conditions

In this study (α/p) = f(E/p) functional relation is derived for the gas mixture of N₂/O₂ by considering Townsend approach, and formation mechanism of corona discharge is investigated for the coaxial electrode system located in this gas medium. The electron energy distribution function (EEDF) which is required for estimation of ionization coefficient, is determined by considering probability distribution function of inelastic electron collisions versus energy. An algorithm for determining ionization coefficient for binary gas mixture is presented. The development and motion of the electron avalanche in inter-electrode gap are studied by considering the effect of positive space charges. It is determined by considering the derived mathematical expressions that the formation of corona discharge is related with the variation of the current characteristics in inter-electrode gaps depending on the change of potential of central electrode.     

Thermally induced effects on structural and electrical properties of selenium-rich Cd-Se thin films

The effect of annealing in nitrogen atmosphere on structural and electrical properties of selenium rich CdSe (SR-CdSe) thin films deposited by thermal evaporation onto glass substrates were studied. X-ray diffraction (XRD) patterns showed that the as-prepared films were amorphous, whereas the annealed films were polycrystalline. Analyzing XRD patterns reveals the coexistence of both Se and CdSe crystalline phases which exhibits a hexagonal structure. The microstructure parameters (crystallite size, microstrain and dislocation density) were calculated for annealed films.Temperature dependence (300–500 K) of d.c. conductivity was studied for as-prepared and annealed thin films. The experimental results indicate that the electrical conduction taking place through thermally activated process. At higher temperatures, electrical conduction for as-prepared film is taking place in the extended states while localized states conduction in the band tails is most likely to take place for annealed films. Regarding the lower temperature range, conduction by hopping in the localized states near the Fermi level is found to be dominant. Thus, conductivity data in this range was analyzed using Mott's variable range hopping conduction, where Mott's parameters were calculated for SR-CdSe thin films.     

The kinetics of precipitation in Al-2.4 wt% Cu alloy by Kissinger, Ozawa, Bosswel and Matusita methods

The isothermal and non-isothermal ageing of an Al-2.4 wt% Cu alloy have been studied using X-ray diffraction analysis and differential scanning calorimetry (DSC) at different heating rates. Quantitative metallography methods have been applied to measure the corresponding transformed volume fractions at various temperatures and times of precipitation. The variation of the heating rate using DSC technique has allowed us to calculate two kinetics parameters of precipitation which are the Avrami exponent and the activation energy of the process using Kissinger, Ozawa and Bosswell methods. These parameters are similar to those found for the precipitation reaction of θ′ and θ (Al₂Cu) phases.     

Designing four naphthalene di-imide based small organic solar cells with 5,6-difluoro-3-oxo-2,3-dihydro-indene non-fullerene acceptors

Optical and Quantum Electronics - In this paper, the simultaneous impact of interference and aggregated hardware impairments on the performance of mixed radio frequency/free space optical (RF/FSO)...     

Exploration of Cytotoxic Potential of Longifolene/Junipene Isolated from Chrysopogon zizanioides

Since ancient times, Chrysopogon zizanioides has been utilized as a traditional medicinal plant for the treatment of numerous ailments, but neither its plant extract form nor its phytoconstituents have been fully explored. With this in mind, the present research was designed to isolate and structurally characterize one of its chemical constituents and evaluate its cytotoxic potential. Therefore, an ethanolic extract of roots was prepared and subjected to column chromatography using solvents of varying polarities. The obtained pure compound was characterized using various chromatographic and spectroscopic techniques such as high-performance liquid chromatography (HPLC), carbon and proton nuclear magnetic resonance (NMR), and liquid chromatography–mass spectroscopy (LC-MS) and identified as longifolene. This compound was evaluated for its cytotoxic potential using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on the prostate (DU-145), oral (SCC-29B) cancer cell line and normal kidney cell line (Vero cells), taking doxorubicin as a standard drug. The obtained outcomes revealed that longifolene possesses cytotoxic potential against both prostate (IC₅₀ = 78.64 µg/mL) as well as oral (IC₅₀ = 88.92 µg/mL) cancer cell lines with the least toxicity in healthy Vero cells (IC₅₀ = 246.3 µg/mL) when compared to doxorubicin. Hence, this primary exploratory study of longifolene exhibited its cytotoxic potency along with wide safety margins in healthy cell lines, giving an idea that the compounds possess some ability to differentiate between cancerous cells and healthy cells.     

Energy–entropy method using multiscale cell correlation to calculate binding free energies in the SAMPL8 host–guest challenge

Free energy drives a wide range of molecular processes such as solvation, binding, chemical reactions and conformational change. Given the central importance of binding, a wide range of methods exist to calculate it, whether based on scoring functions, machine-learning, classical or electronic structure methods, alchemy, or explicit evaluation of energy and entropy. Here we present a new energy–entropy (EE) method to calculate the host–guest binding free energy directly from molecular dynamics (MD) simulation. Entropy is evaluated using Multiscale Cell Correlation (MCC) which uses force and torque covariance and contacts at two different length scales. The method is tested on a series of seven host–guest complexes in the SAMPL8 (Statistical Assessment of the Modeling of Proteins and Ligands) “Drugs of Abuse” Blind Challenge. The EE-MCC binding free energies are found to agree with experiment with an average error of 0.9 kcal mol^?1. MCC makes clear the origin of the entropy changes, showing that the large loss of positional, orientational, and to a lesser extent conformational entropy of each binding guest is compensated for by a gain in orientational entropy of water released to bulk, combined with smaller decreases in vibrational entropy of the host, guest and contacting water.

     

Enhanced catalytic features of sol-gel immobilized MnP isolated from solid state culture of Pleurotus ostreatus IBL-02

An indigenous and industrially important manganese peroxidase (MnP) isolated from solid state culture of Pleurotus ostreatus IBL-02 was 2.1-fold purified and immobilized using sol-gel matrix of trimethoxysilane and proplytetramethoxysilane. Lower KM, higher Vmax, hyper-activation, enhanced acidic and thermal stability up to 70℃, were the improved/enhanced catalytic features of the presently sol-gel immobilized MnP. A maximum of 100% decolorization was achieved within a short time period for the different real dyes containing textile industry effluents i.e. Nishat textile (NIT), K&N textile (KIT), Sitara textile (SIT), and Crescent textile (CRT).     

Numerical study of melting and solidification in a wavy double-pipe latent heat thermal energy storage system

Journal of Thermal Analysis and Calorimetry - The objective of this paper is to develop the influences of channel waviness on the performance of a latent heat storage system during phase change...     

Study on the performance assessment of a novel hybrid heat pump system modified with dedicated mechanical sub-cooler for domestic heating applications

Journal of Thermal Analysis and Calorimetry - This article investigates the performance of a novel hybrid heat pump system, which is developed to recover the waste heat from the flue gas of...     

Chemical destabilization of oil-in-water emulsion by novel polymerized diethanolamines

The main objective of this study was to synthesize novel demulsifiers for resolving oil-in-water emulsions. Diethanolamine polyethers are considered as a cationic polymer type. The study describes an improved synthesis of a series of diethanolamine polyethers via condensation of 3-7 or 9 mol of diethanolamine. The structure and the molecular weights of the major components in the reaction mixture were confirmed via IR and MS analyses. The demulsifiers were used for treatment of pollution in the refinery wastewater with or without FeCl3. The flocculation efficiency of the synthesized demulsifiers was determined by turbidity measurement of the treated and untreated O/W emulsion in the Cairo Oil Refinery Company. The critical flocculation concentration (CFC) and charge density of the synthesized demulsifiers were determined. Biodegradation of diethanolamine polyethers was measured in river water within 7-8 days.