391 research outputs found
Absolute Measurements for Uranium Verification Content in Radiographic Containers
Depleted Uranium (DU) is used for its very high density in civilian uses include radiation shielding in medical radiation therapy, industrial radiography equipment, containers used to transport radioactive materials. Absolute measurements have been performed for verification of uranium mass content in gamma radiography by using detector’s model developed with MCNP in nuclear safeguard inspection for these samples. Both the experimental results obtained as well as MCNP results are used to estimate the 238U mass content. The determined and the declared 238U masses values are found in an agreement with accuracy from -1.74 % to 1.80 %
EFFECT OF FIRING TEMPERATURE AND COMPACTING PRESSURE ON THE MAGNETIC AND ELECTRICAL PROPERTIES OF NICKEL FERRITE
Spinel ferrites have attracted considerable attention and efforts continue to investigate them for their technological importance to the microwave industries, high speed digital tape or disk recording and magnetic refrigeration system. NiFe 2 O 4 was prepared by mixing pure nickel oxide and iron oxide, dried, pressed at 150, 200, and 250 kg/cm 2 , then fired at 1273, 1373 and 1473 K for 10 hours. X-ray diffraction was used to assess the formation of NiFe 2 O 4 . Results showed that density increases with increasing either hydraulic pressing and firing temperature. Magnetic properties are measured and an isoperm hystersis loop is obtained, remenant magnetic flux induction, saturation magnetic flux induction and corecive force are calculated and found to be density dependant. Electrical properties of NiFe 2 O 4 were measured and it was found that it has low electrical conductivies (10 -6 -10 , and values of dielectric constant, and dielectric loss are consistant with semiconductors properties
Synthesis and spectral studies of 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxybenzaldehyde(TA)and its Schiff bases with 1,3-diaminopropane(TAAP)and 1,6-diaminohexane(TAAH).Their analytical application for spectrophotometric microdetermination of cobalt(II).
Cataloged from PDF version of article.The new azo compound 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxy-benzaldehyde (TA) and its Schiff bases with 1,3-diaminopropane
(TAAP) and 1,6-diaminohexane (TAAH) have been synthesized. The bands of diagnostic importance in the IR and the main signals
in 1
H NMR spectra are assigned. The electronic absorption spectra in pure organic solvents of different polarity and in buffer
solutions of varying pH are investigated. The quantitative description of the solvent effect on the electronic absorption spectra is
studied and their acid ionization constants are determined. Also, a new simple and sensitive method for the spectrophotometric
microdetermination of Co(II) using these compounds (TA, TAAP and TAAH) as new chromogenic reagents is established. The
developed method is successfully used for the determination of trace amounts of cobalt in authentic samples and calculation of the
distribution ratio of cobalt adsorbed on bentonite and kaolinite clay minerals.
2004 Elsevier Ltd. All rights reserved
Analysing faults and SFCL response in electric aircraft
Aircraft technology moves towards electrification in order to achieve environmentally friendly goals. However, one of the main challenges facing the electrification of aircraft technology is the weight of the electric devices necessary for operating a fully electric aircraft. The National Aeronautics and Space Administration (NASA) proposed the use of the superconductive technology in electric aircraft (EA) to overcome this challenge in addition to its other benefits. The proposed EA is called N3-X and it has an on-board DC superconducting network including a superconducting fault current limiter (SFCL). The SFCL is a self-mechanism device that very effectively limits the current within a few milliseconds, thus improving the stability of the system. As the grounding of this network is different from traditional networks, analysing the behaviour of different fault types and how to manage them becomes critical. In this paper, one set of the EA's systems (one generator, AC/DC rectifier and four motors with their DC/AC variable frequency drives) has been modelled in MATLAB/Simulink environment to carry out the fault analysis and to demonstrate the effect of the SFCL on this network under different types of faults
On pairwise super continuous mappings in bitopological spaces
The aim of this paper is to define and study super-continuous mappings and some
other forms of continuity such as strong continuity, perfect continuity and complete continuity in
bitopological spaces and investigate the relations between these kinds of continuity and their effects
on some kinds of spaces
Development and Validation of an MCNP model for a Broad-Energy Germanium Detector
An MCNP model was developed for a Broad-Energy Germanium Detector (Model BE2830). This model was constructed based on the manufacturer specifications provided for the detector. In order to develop the complete MCNP model, the activity of three standard radioactive sources (Co-57, Co-60 and Cs-137) was calculated by estimating the detector absolute full energy peak efficiency at different gamma-ray energy lines, using the MCNP model, and measuring count rates due to those energy lines, using the BEGe detector, with different setup configurations. The obtained results were in agreement with certified values with a relative difference ranging from -1.84% to 1.57%. As an application for the constructed MCNP model, 235U mass contents for five Standard Nuclear material (SNM) samples were estimated. The obtained results indicate that this model could be used effectively for nuclear safeguards purposes
TRA-954: SOLUTION MODEL FOR URBAN TRAFFIC CONGESTION: EGYPTIAN CASE STUDY
Traffic congestion is a major problem in many cities around the world resulting in massive delays, increased fuel wastage, environmental impact and other negative consequences affecting the daily life of each individual. From a transportation engineering point of view, making the correct decision to eliminate such congestion problems can be very difficult for decision-makers who carry the burden of analyzing large quantities of data which could be vague and conflicting in nature. Therefore, an effective and consistent system is required to simplify the decision-making process of the traffic congestion control. Traffic simulation could be that tool.
The seriousness of traffic congestion in Egypt is the main motive for the study presented herein. The study aims at developing a model that sets guidelines on how to approach an urban congested traffic area, be able to tackle the problem and choose the effective engineering solution in terms of either geometry and/or structure.
Sectors of El Nasr Road, Cairo with a total length of 2.4 km is chosen as a typical example of an urban area with traffic congestion hotspots. It serves as an excellent location to implement the traffic solution model on.
The model is developed and implemented as follows: collection of traffic data, diagnosis of the congestion problems in terms of social, commercial, cultural, and behavioral aspects. The analysis of the data finger points out the flag areas by conducting total and peak traffic volume counts, simulation of the existing traffic conditions to get the delayed travel times of vehicles in that area. The analysis of the output would finally help decide whether such problem would be solved by geometric adjustments of the surface or the problem requires a multi-layered intersection
Three-Dimensional Human iPSC-Derived Artificial Skeletal Muscles Model Muscular Dystrophies and Enable Multilineage Tissue Engineering
Summary: Generating human skeletal muscle models is instrumental for investigating muscle pathology and therapy. Here, we report the generation of three-dimensional (3D) artificial skeletal muscle tissue from human pluripotent stem cells, including induced pluripotent stem cells (iPSCs) from patients with Duchenne, limb-girdle, and congenital muscular dystrophies. 3D skeletal myogenic differentiation of pluripotent cells was induced within hydrogels under tension to provide myofiber alignment. Artificial muscles recapitulated characteristics of human skeletal muscle tissue and could be implanted into immunodeficient mice. Pathological cellular hallmarks of incurable forms of severe muscular dystrophy could be modeled with high fidelity using this 3D platform. Finally, we show generation of fully human iPSC-derived, complex, multilineage muscle models containing key isogenic cellular constituents of skeletal muscle, including vascular endothelial cells, pericytes, and motor neurons. These results lay the foundation for a human skeletal muscle organoid-like platform for disease modeling, regenerative medicine, and therapy development. : Maffioletti et al. generate human 3D artificial skeletal muscles from healthy donors and patient-specific pluripotent stem cells. These human artificial muscles accurately model severe genetic muscle diseases. They can be engineered to include other cell types present in skeletal muscle, such as vascular cells and motor neurons. Keywords: skeletal muscle, pluripotent stem cells, iPS cells, myogenic differentiation, tissue engineering, disease modeling, muscular dystrophy, organoid
In ovo protective effects of chicoric and rosmarinic acids against Thiacloprid-induced cytotoxicity, oxidative stress, and growth retardation on newly hatched chicks
Thiacloprid (TH) is a neonicotinoid insecticide employed in agriculture to protect fruits and vegetables against different insects. It showed different deleterious effects on the general health of non-target organisms including birds and animals, however, its developmental toxicity has yet to be fully elucidated. Chicoric (CA) and rosmarinic (RA) acids are polyphenolic compounds with a wide range of beneficial biological activities. In this study, the possible protective effects of CA and RA were investigated in chick embryos exposed in ovo to TH (1mg/egg) with or without CA (100 mg/egg) or RA (100 mg/egg) co-exposure. TH reduced the hatchling body weight, body weight/egg weight, and relative weight of bursa of Fabricius in the
one-day-old hatchlings. Examination of the 7-day-old chicks revealed a decline in feed intake, daily weight gain, feed conversion ratio (FCR), and plasma levels of T3, T4, and growth hormone. Serum ALT, AST activities, and total cholesterol levels showed significant elevations. Hepatic MDA was increased with a reduction in SOD activity and GSH level and downregulation of the
liver SOD and GST gene expression pattern. Serum IgG and IgM levels were reduced, and various histopathological alterations were noticed in the liver. Co-administration of CA or RA with TH mitigated the toxic effects on hatchlings. When both CA and RA are combined, they
present a synergistic protective effect. CA and RA can be used as protective agents against TH toxicity as they improve growth performance and have hepatoprotective and immunostimulant effects in newly hatched chicks
Clinical characteristics, sepsis interventions and outcomes in the obese patients with septic shock: an international multicenter cohort study
La calidad educativa de los centros de hoy depende del nivel de competencias adquirido por sus educadores (Perrenoud, 2002). En este sentido, debemos apostar por un equipo humano formado por sujetos que sepan superarse permanentemente, aptos para ejercer tareas dinámicas y cambiantes y que compartan alternativas para crecer en todos los sentidos. Más todavía, debemos apostar por profesionales capaces de identificar y dominar los procesos que se deben realizar actuando con decisión y responsabilidad. La adquisición de competencias comporta aptitud y actitud para utilizar conocimientos, más concretamente, habilidades y valores, de manera interdisciplinaria, transversal e interactiva en contextos y situaciones que requieren la intervención de contenidos vinculados a las diferentes áreas del currículum (Lleixà, 2007), sin exclusividad, en este caso, del área de Educación Física. Presentamos una propuesta metodológica, el «Paradigma Estratégico para el desarrollo de habilidades competenciales», cuya ejecución implica comprensión, reflexión y discernimiento, teniendo en cuenta la dimensión social de cada situación. El estudio se ha llevado a cabo en la Universidad de Lleida con 40 alumnos de tercer curso de la asignatura «Educación Física y su didáctica». Se pretende valorar el impacto que provoca la implementación del programa «Paradigma estratégico para la adquisición de habilidades competenciales» sobre sus propias percepciones competenciales intrapersonales, antes y después de la aplicación de dicho programa
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