Isothermal Cylindrical Couette Flow Of Oldroyd 8-Constant Model Fluid Up To Second-order

The steady flow of an incompressible Oldroyd 8-constant fluid in the annular region between two concentric cylinders, or so-called cylindrical Couette flow, is investigated. The inner cylinder rotates with an angular velocity about its own axis, z-axis, while the outer cylinder is kept at rest. The viscoelasticity of the fluid is assumed to dominate the inertia such that the latter can be neglected in the momentum equation. An analytical solution is obtained through the expansion of the dynamical variables in power series of the dimensionless retardation time. The primary velocity term denotes the Newtonian rotation about the z-axis. The first-order is a vanishing term. The second-order results in a secondary flow represented by the stream-function. This second-order term is the viscoelastic contribution to the primary viscous flow. The second-order approximation depends on the four viscometric parameters of the fluid

Alpha self-absorption evaluation in radiometric filter material for the natural range of alpha energy (5-9 MeV)

In this paper, SRIM (The Stopping and Range of Ions in Matter) software package is used to simulate the interaction of alpha particles into the material of radiometric analytical filters. The effect of alpha particle self-absorption in alpha radiometric filters measurements is estimated, especially in the range of natural alpha energy (5-9 MeV, Radon and Thoron alpha energy). Software package SRIM allows to calculate the parameters of the ions interaction with target material using a Monte Carlo simulation method based on a quantum mechanical treatment of ion-atom collisions. The effect of the radiometric analytical filter material on the transmitted efficiency of alpha energy is discussed. As the energy increases the self-absorption in analytical filter material is decreased but still has a clear effect. In this case, the filter material and the space distance between the filter and the detector window decrease the number of alpha particles which reach to the detector window. © 2019 RAD Association. All rights reserved

Available nutrients and some soil properties of El-Qasr soils, El-Dakhla Oasis, Egypt

Ten surface soil samples (0-30 cm) were collected from El-Qasr village, El-Dakhla Oasis, New Valley, Egypt to investigate some soil properties and nutrients availability. The results revealed that most of the soil texture varied clay loam to sandy clay loam. The mean values of bulk density (BD), soil pH, electric conductivity (EC), saturation percentage (SP), calcium carbonate (CaCO3), cation exchangeable capacity (CEC), organic matter (OM), and sodium adsorption ratio (SAR) were 1.42 gcm3, 7.89, 3.34 dSm-1, 52.10%, 7.46 %, 28.08 cmol (+) kg-1, and 3.65, respectively. The mean values of N, P, and K were 99.37, 31.32, 121.93, mg/kg, respectively. Meanwhile, the mean values of Fe, Mn, Cu and Zn were 27.39, 18.38, 0.48, and 3.48 mgkg-1, respectively. The correlations coefficient of NPK was strongly positively significant relationship with clay, OM, CEC, and SAR, but they negatively correlated with pH, EC, CaCO3. Meanwhile, Fe, Mn, and Cu were positively correlated with EC, CaCO3, while they negatively correlated with clay, pH, OM, CEC, and SAR. Also, Zn was negatively correlated with clay, pH, EC, OM, and CaCO3, and it positively correlated with CEC and SAR

Effect of electronic cigarette (EC) aerosols on particle size distribution in indoor air and in a radon chamber

Particle size distribution is an important factor governing whether aerosols can be deposited in various respiratory tract regions in humans. Recently, electronic cigarette (EC), as the alternative of tobacco cigarette, has become increasingly popular all over the world. However, emissions from ECs may contribute to both indoor and outdoor air pollution; moreover, comments about their safety remain controversial, and the number of users is increasing rapidly. In this investigation, aerosols were generated from ECs and studied in the indoor air and in a chamber under controlled conditions of radon concentration. The generated aerosols were characterized in terms of particle number concentrations, size, and activity distributions by using aerosol diffusion spectrometer (ADS), diffusion battery, and cascade impactor. The range of ADS assessment was from 10 -3 μm to 10 μm. The number concentration of the injected aerosol particles was between 40 000 and 100 000 particles/cm 3 . The distribution of these particles was the most within the ultrafi ne particle size range (0-0.2 μm), and the other particle were in the size range from 0.3 μm to 1 μm. The surface area distribution and the mass size distribution are presented and compared with bimodal distribution. In the radon chamber, all distributions were clearly bimodal, as the free radon decay product was approximately 1 nm in diameter, with a fraction of ~0.7 for a clean chamber (without any additional source of aerosols). The attached fraction with the aerosol particles from the ECs had a size not exceeding 1.0 μm. © 2019 H. N. Khalaf, M. Y. A. Mostafa & M. Zhukovsky

Water Absorption Enhancement Of Sodium Poly Acrylate And Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) Based Hydrogel Mixtures

Introduction: Hydrogels are hydrophilic polymers which are cross-linked to form three-dimensional structures, which can absorb, swell and retain huge amounts of water or aqueous fluids. Objective: This paper reports the preparation and characterization of Poly (2-Acrylamido-2-Methylpropane Sulphonic Acid) (PAMPS) hydrogel with different crosslinking intensities. Methodology: 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) monomer was purchased from Alfa Aesar Company as reagent grade. It was used as received (\u3e98% purity) without any further purification. PAMPS hydrogel was prepared by free radical crosslinking solution polymerization of AMPS in water at room temperature under a nitrogen blanket in cylindrical glass tubes. The characteristics of the obtained PAMPS hydrogel were compared with those of commercial sodium polyacrylates hydrogel. Results: It was found that decreasing the crosslinker weight improved the absorbance capacity but to a limit. The suggested reasons were discussed. The mixture showed higher absorbance rate than PAMPS, and bigger absorbance capacity than sodium polyacrylates. Conclusion: This paper investigates the effect of crosslinker ratio on the swelling capacity of PAMPS. It was found that as the crosslinking ratio decreases, the porosity of the hydrogel increases, thus improving the swelling capacity

Radiopharmaceutical dose distribution in different organs and tissues for Lu-177 with different carrier

177Lu refers to rare earth elements from a group of lanthanides. Relative to its short time span, 177Lu has virtually pervaded all areas of in vivo radionuclide therapy and becomes one of important keys for therapeutic radionuclides of choice for targeted radionuclide therapy. The rising interest in the use of 177Lu in targeted molecular therapies has primarily developed from recent unmatched advances in molecular and cell biology, which include the use of peptides targeted to cell surface receptors, which are overexpressed on the surface of tumour cells. Therefore, the use of 177Lu-labelled radiopharmaceuticals have been the major factors evoking excitement among researchers and capturing the imagination of the clinical community thanks to advances in molecular and cellular biology. In this work, radiopharmaceutical comparison for 177Lu absorbed dose in health human organs and tissues is presented. The comparison between unlabelled 177Lu (ionic form) and labelled with 177Lu-MDP (methylenediphosphonate) and 177Lu-MAb (monoclonal antibodies). The biokinetic model in each case are described and presented. The absorbed dose in health human organs and tissues are simulated with two recommended programs WinAct and IDAC 2.1(Internal Dose Assessment by Computer) software. The distribution of absorbed dose in the main organs nearly the same with different in the value for the ionic form and 177Lu-MDP. The absorption in the case of ionic form is high. The distribution is completely change while 177Lu-MAb is used. The most absorbed dose fraction goes to spleen and liver unlike bone surface absorb nearly 50 % of dose. © 2019 Author(s)