HPGe detector photopeak efficiency calculation including self-absorption and coincidence corrections for cylindrical sources using compact analytical expressions

Total and full-energy peak efficiencies, coincidence correction factors and the source self-absorption of a p-type coaxial HPGe detector for cylindrical sources have been calculated using direct analytical expressions. In the experiments gamma aqueous sources containing several radionuclides covering the energy range from 60 to 1836 keV were used. By comparison, the theoretical and experimental full-energy peak efficiency values are in good agreement.     

Synthesis and Structural Characterization of Bis(tetrahydro­pyran)calcium Bis[bis(trimethylsilyl)amide]

Transmetalation of Sn[N(SiMe₃)₂]₂ with calcium granules in tetrahydropyran (thp) yields colorless [(thp)₂Ca{N(SiMe₃)₂}₂] ( 1 ) which is soluble in common organic solvents. The calcium center is in a distorted tetrahedral environment with Ca–N and Ca–O bond lengths of 231.08(11) and 240.23(9) pm, respectively. The molecular structure is dominated by steric factors leading to a NCaN bond angle of 119.43(6)°.     

Design and Implementation of a Scalable RFID-Based Attendance System with an Intelligent Scheduling Technique

Radio Frequency Identification (RFID) technology; a convenient and flexible technology which is well suited for fully automated systems, is directing human lifestyle towards automation and reality. Integrating RFID into attendance management systems makes the tasks of both users and administrators easy, smart, convenient, and practical. Earlier implementations of RFID-based attendance systems involve different approaches and facilities. Different intertwined characteristics (i.e., scalability, and automation) are suggested in evaluating the performance of these systems. The coverage of these characteristics appears to be adequate in achieving a good systems implementation. Some of the existing systems present high performance; however, these systems still have gaps in some of the suggested characteristics. In order to mind these gaps, a scalable RFID-based attendance system with an intelligent scheduling technique; called Intelligent and fully Automated Attendance System (IAAS), has been designed and implemented. Finally, the performance of IAAS has been evaluated through a comparison with existing attendance systems.     

Large-Eddy Simulations of cavitation in a square surface cavity

We report on the development and application of a multiphase approach to the prediction of cavitation induced by high-speed flow over and within a square surface cavity. The approach entails employing a full cavitation model in conjunction with Large-Eddy Simulations in order to capture the initiation and development of bubble formations in turbulent-flow conditions. The incipient formation of the bubble cloud, and the flow processes of vortex shedding and shear-layer oscillations are tracked using the Volume of Fluid method. The validity of the computational approach was assessed by comparisons with experiments on cavitating flow over a hydrofoil. Application to the case of flow over and within a two-dimensional square cavity with cavitation clearly reveal the presence of traveling cavitation at the corner of the cavity trailing edge, and vortex cavitation within the cavity. It is shown that the collapse of cavitation bubbles results in an impact frequency that is higher than the frequency of the shear-layer oscillations. This implies that structural damage due to cavitation is likely to be most severe at the corner formed at the intersection of the cavity’s trailing edge and the flat surface upstream of it.     

Reply to comments on "Interference from 24-GHz automotive radars to passive microwave Earth remote sensing satellites"

We appreciate that authors Kerr et al. concur that our paper [ibid., vol.42, no.7, p.1387-98 (2004)] provides the right approach to the analysis of potential interference from anthropogenic sources to remote sensing satellites. The potential for such interference is likely to grow as new active systems are developed, necessitating acceptable procedures for interference analysis based on accepted scientific knowledge and engineering principles. While some simple clarifications are in order to improve the acceptability of our procedure, we suggest, however, that Kerr et al. have not studied our paper in detail and misinterpret several points.     

The Synthesis of New Spiro β-Lactam and Thiazolidinone Compounds Incorporating Quinones and Their Biological Activity

A series of some fused and spiro heterocyclic compounds such as pyrazolines, isoxazolines, pyrimidines, β-lactams, and thiazolidinone derivatives incorporating compounds 3, 6a–d, 7a–d, 9a–c, 10a–c, 11a–c, 12a–c, and 13a–c have been synthesized by a cycloaddition and cyclocondensation reaction of monochloroacetyl chloride, mercaptoacetic acid, hydrazines, hydroxylamine, urea, and thiourea with the prepared 5a–d and 8a–c.     

Studies on Organophosphorus Compounds VII1,2: Transformation of Steroidal Ketones with Lawesson's Reagent into Thioxo and Heterofused Steroids. Results of Antimicrobial and Antifungal Activity

The reactivity of Lawesson's reagent (LR) toward some steroidal hormones was studied, 4-androsten-3,17-dione 2 reacted with LR to produce the corresponding thioxosteroids 3 and 4. Epi-androsterone 5 showed a great activity to LR and produced 3β-mercaptospiro-(androstan-17,4′dithiaphosphetan)thione 8 and the sulfide derivative 9. Also progesterone 10 reacted with LR to yield the thiaphospholo[3′, 4′:16,17]androsten-3-one 13 and the sulfide product 16. The new modified steroidal derivatives thieno[2′,3′:2,3]cholestan 18 and thieno[2′,3′:2,3]-androstan 20 were synthesized and examined against LR, the corresponding thiazaphosphorinothieno steroidal derivatives 23 and 24 were isolated respectively. The in vitro biological activity of some newly synthesized compounds against bacteria, yeast, and fungi was studied.     

Simulation of flow in an exact replica of a diseased human carotid artery

We report on results of ongoing efforts directed towards the development of a computational model for flow in diseased human carotid arteries. Recent visualizations of the flow in an exact replica of an actual diseased artery have revealed the presence of complex, three-dimensional flow structures characterized by multiple recirculation zones and the formation of unstable jets in both the internal and external arteries. Even though the flow conditions at inlet to the artery were kept steady, the experiments showed that the resulting flow downstream of the inlet was unsteady and chaotic. The present computations aim to determine whether such behavior can be captured with a practical finite-volume computational model, and to examine the impact of spatial and temporal resolution on the quality of simulations.     

Multifrequency excitation of an inclined marine riser under internal resonances

Nonlinear Dynamics - We study the multifrequency excitation of an inclined marine riser under two-to-one and three-to-one internal resonances. The riser model accounts for the initial static...     

Predicting Systolic Blood Pressure in Real-Time Using Streaming Data and Deep Learning

Mobile Networks and Applications - High systolic blood pressure causes many problems, including stroke, brain attack, and others. Therefore, examining blood pressure and discovering issues related...