Optimization of hot melt extrusion parameters for sphericity and hardness of polymeric face-cut pellets

The aim of this study was to formulate face-cut, melt-extruded pellets, and to optimize hot melt process parameters to obtain maximized sphericity and hardness by utilizing Soluplus^® as a polymeric carrier and carbamazepine (CBZ) as a model drug. Thermal gravimetric analysis (TGA) was used to detect thermal stability of CBZ. The Box–Behnken design for response surface methodology was developed using three factors, processing temperature (?°C), feeding rate (%), and screw speed (rpm), which resulted in 17 experimental runs. The influence of these factors on pellet sphericity and mechanical characteristics was assessed and evaluated for each experimental run. Pellets with optimal sphericity and mechanical properties were chosen for further characterization. This included differential scanning calorimetry, drug release, hardness friability index (HFI), flowability, bulk density, tapped density, Carr’s index, and fourier transform infrared radiation (FTIR) spectroscopy. TGA data showed no drug degradation upon heating to 190?°C. Hot melt extrusion processing conditions were found to have a significant effect on the pellet shape and hardness profile. Pellets with maximum sphericity and hardness exhibited no crystalline peak after extrusion. The rate of drug release was affected mainly by pellet size, where smaller pellets released the drug faster. All optimized formulations were found to be of superior hardness and not friable. The flow properties of optimized pellets were excellent with high bulk and tapped density.     

Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets

Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO₃ acid (0.1 M) after a short contact time (15 min).     

Technical and economical/financial feasibility analyses of flared gas recovery in Egypt from oil and gas industry from international/national oil companies’ perspectives

Egypt is an importer of energy, yet 5.7 MMSCM (200 MMSCF) of natural gas is flared every day and causes a negative environmental impact. Recovery of such significant amount is crucial and accordingly there are three alternative solutions to recover these gases, namely LPG/condensate extraction, recycling, or power generation. These alternatives were studied technically, financially, and economically, and results indicate that investors’ orientation and vision play a vital role in decision making especially when production sharing agreement is applied. The conflict of interest among investors was tackled and applied on a case study from different perspectives. Results indicate that the added value itself differs from one investor to another. In the case studied, international oil companies “IOCs” prefer recycling to achieve reasonable net present value “NPV” up to $40 million. National oil companies “NOCs” prefer generating power to achieve maximum net value added “NVA” up to $58 million, to maximize the environmental and social added value. The least feasible option is extracting LPG/condensate from the flared gas although Egypt is LPG importer. The conflict of interest and current oil prices are the reasons behind postponing such projects. So, Egyptian government should impose policies to reduce flared gas emissions and maximize benefits through these projects and this can be done by compromising with “IOCs” to ensure maximum financial/social benefits.     

Cutoff frequency and responsivity limitation of AlInAs/GaInAs MSMPD using a two dimensional bipolar physical model

Using a 2-D bipolar physical model we highlight the main parameters that govern the long-wavelength MSM PD performance (cutoff frequency and responsivity). This covers applied potential, electrode spacing, absorbing layer thickness, and heterojunction effect. We also report that using a backside illumination technique and a thin absorbing layer we can reach a cutoff frequency as high as 65 GHz with a responsivity of 0.2 A/W     

Bayesian prediction of the jth order statistic with burr distribution and a random sample size

This work is concerned with the Bayesian prediction problem of the j order statistic when the size of the future sample is a random variable and the samples are drawn from a generalized Burr distribution (GBD). A numerical illustration is also given.     

Stress Corrosion Cracking of Inconel 600 in aqueous solutions at elevated temperature part I: Initiation and inhibition of corrosion cracking process

The study reported here has been designed to determine the influencing effect of sulphate ions on chloride induced crack initiation of Inconel 600 using compact tension (CT) samples in chloride containing aqueous solutions at elevated temperature up to 250°. The results show that sulphate ions retard the effect of chloride ions on crack initiation in hot water up to 250°. Intergranular stress corrosion cracking (IGSCC) occurs in both chloride solution and in chloride solution with relatively low concentration of sulphate ions. The mode of cracking changes from brittle to ductile failure due to the influence of inhibiting concentration of sulphate. The results are interpreted in the light of repassivation-dissolution controlled mechanism which is the predominant mechanism. The inhibiting effect of sulphate ions on the initiation of corrosion cracking is attributed to the repassivation and the formation of Fe-Cr-spinel oxide layer which is stable also at higher temperature.     

Modified cuckoo search algorithm in microscopic image segmentation of hippocampus

Microscopic image analysis is one of the challenging tasks due to the presence of weak correlation and different segments of interest that may lead to ambiguity. It is also valuable in foremost meadows of technology and medicine. Identification and counting of cells play a vital role in features extraction to diagnose particular diseases precisely. Different segments should be identified accurately in order to identify and to count cells in a microscope image. Consequently, in the current work, a novel method for cell segmentation and identification has been proposed that incorporated marking cells. Thus, a novel method based on cuckoo search after pre‐processing step is employed. The method is developed and evaluated on light microscope images of rats’ hippocampus which used as a sample for the brain cells. The proposed method can be applied on the color images directly. The proposed approach incorporates the McCulloch's method for lévy flight production in cuckoo search (CS) algorithm. Several objective functions, namely Otsu's method, Kapur entropy and Tsallis entropy are used for segmentation. In the cuckoo search process, the Otsu's between class variance, Kapur's entropy and Tsallis entropy are employed as the objective functions to be optimized. Experimental results are validated by different metrics, namely the peak signal to noise ratio (PSNR), mean square error, feature similarity index and CPU running time for all the test cases. The experimental results established that the Kapur's entropy segmentation method based on the modified CS required the least computational time compared to Otsu's between‐class variance segmentation method and the Tsallis entropy segmentation method. Nevertheless, Tsallis entropy method with optimized multi‐threshold levels achieved superior performance compared to the other two segmentation methods in terms of the PSNR.     

Cu and Ag Nanoparticles Films Deposited on Glass Substrate Using Cold Cathode Ion Source

Structural, electrical and optical properties of Cu and Ag nanoparticles thin films deposited on glass substrates prepared by sputtering were investigated. Cold cathode ion source used for sputtered of copper and silver targets to deposit nanoparticles thin films on glass substrate using argon gas. X-ray diffraction was used to study the structure and the grain size of thin film which reveals that average grain size is in nano region. Copper nanoparticles was in rang 14 nm and silver nanoparticles size was 20 nm in first peak using Scherrer’s method. The electrical resistivities of copper and silver thin films were also investigated. The thin film resistance Rs of Cu and Ag equals 1.33 and 6.35 Ω respectively. I-V characteristics of thin films were recorded at room temperature and are found to be linear. Optical properties of the synthesized materials are studied by UV–Vis in the wavelength range 200–800 nm. The calculated band gap for the Cu thin film on glass are estimated to be E_gCu = 2.18 eV.