Research on reaction prıducts of 11B+186W (68 MeV) and 15N+176Yb (82 MeV) reactions

Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır. Yayınlanma izni olmayan tezlerin basılı kopyalarına Üniversite kütüphaneniz aracılığıyla (TÜBESS üzerinden) erişebilirsiniz.Fen Bilimleri Enstitüsü, Fizik Ana Bilim DalıÖZET nB + 186W (68MeV) ve 15N +_,76Yb(82 MeV) Enerjüeriyle Oluşturulan Reaksiyon Ürünlerinin İncelenmesi PELİN KURT Niğde Üniversitesi Fen Bilimleri Enstitüsü Fizik Anabilim Dalı Danışman: Doç. Dr. Sefa ERTÜRK Haziran 2003, 105Sayfe Bu tez çalışmasında, deneysel kısmı YALE üniversitesi (USA) WNSL (Wright Nuclear Structure Laboratory)'de gerçekleştirilen 186W(IlB,xpn) Au, Pt reaksiyonu sonucu elde edilen,90-191'192'193Au izotoplarının reaksiyon kanalları içerisindeki oranlarının hesaplanması amaçlanmıştır. Bunun için WNSL'de bulunan TANDEM hızlandırıcısı kullanılarak elde edilmiş olan nB iyonu 186W hedefi üzerine gönderilerek oluşturulan kararsız Au çekirdeğinden ağır iyon füzyon buharlaştırma yöntemiyle farklı sayıda nötron ve proton buharlaştırılarak I90,i9i,i92,i93^u jj^^pjajj eye edilmiştir. Bu izotoplara ait deneysel veriler yine WNSL'de bulunan YRAST BALL (Yale Rochester Array for SpecTroscopy) çoklu dedektör topluluğunun kuUanımıyla alınmıştır. Alınan bu deneysel veriler manyetik teyplere kaydedilmiş ve üç boyutlu matrisler oluşturularak herbirine ah seviye şemaları elde edilmiştir. Bu seviye şemaları linux işletim sistemi içeren bir bilgisayar ortamına alınarak herbir seviye şemasına ait analizler RADWARE paket programı içerisinde bulunan Levit8r ve Gf3 programlan kullanılarak yapılmıştır. Bu analiz sonuçlarının değerlendirilmesiyle de her bir çekirdeğin reaksiyon içindeki oluşum oranlan, yani tesir kesitleri hesaplanmıştır. Anahtar Kelimeler: Dedektör, Seviye şeması, Füzyon reaksiyonları inSUMMARY Research on Reaction Products of nB+186W (68MeV) and 15N + 176Yb (82MeV) Reactions KURT, Pelin Nigde University Graduate School of Natural and Applied Sciences Department of Physics Supervisor: Ass. Prof. ERTURK Sefa June 2003, 105 pages The aim of this work is to determine the ratios in the reaction channels of 190Au, 191Au, 192 Au and 193Au isotops which are produced in nB+I86W (68MeV) reaction performed at Yale University USA, WNSL (Wright Nuclear Structure Laboratory). nB beam is obtained from TANDEM accelerator at WNSL at Yale University and delivered to W target to populate an unstable compound nucleus which emits some neutron and gamma rays and produces 190Au, 191Au, 192Au and I93Au isotops via fusion-evaporation reaction. All these particles and gamma rays were detected with YRAST Ball (Yale Rochester SpecTroscopy) array. These data were recorded on magnetic tapes and the level schemes of these isotop were obtained via three dimensional cubes. These level schemes were analyzed in linux system using Radware program which includes levit8r and go analysis programs. These programs are used for this analysis to determine the ratios of each isotops in the reaction channels. Keywords: Detector, Level scheme, Fusion reactions

Improving Physician Schedules by Leveraging Equalization: Cases from Hospitals in U.S.

In this paper, we consider physician scheduling problems originating from a medical staff scheduling service provider based in the United States. Creating a physician schedule is a complex task. An optimal schedule must balance a number of goals including adequately staffing required assignments for quality patient care, adhering to a unique set of rules that depend on hospital and medical specialties, and maintaining a work-life balance for physicians. We study various types of physician and hospital requirements with different priorities, including equalization constraints to ensure that each provider will receive approximately the same number of a specified shift over a given time period. A major challenge involves ensuring an equal distribution of workload among physicians, with the end goal of producing a schedule that will be perceived by physicians as fair while still meeting all other requirements for the group. As the number of such equalization constraints increases, the physician scheduling optimization problem becomes more complex and it requires more time to find an optimal schedule. We begin by constructing mathematical models to formulate the problem requirements, and then demonstrate the benefits of a polyhedral study on a relaxation of the physician scheduling problem that includes equalization constraints. A branch-and-cut algorithm using valid inequalities derived from the relaxation problem shows that the quality of the schedules with respect to the soft constraints is notably better. An example problem from a hospitalist department is discussed in detail, and improvements for other schedules representing different specialties are also presented

A Comparison of Ramipril and Bevacizumab to Mitigate Radiation-Induced Brain Necrosis: An Experimental Study

Background: Bevacizumab, an anti-vascular endothelial growth factor (VEGF) antibody, is a new treatment approach for radionecrosis. In our study, we compared the prophylactic and therapeutic usage of a promising agent, ramipril (an angiotensin-converting enzyme inhibitor), with that of bevacizumab for reducing radiation-induced brain injury after high-dose stereotactic radiosurgery (SRS). Methods: A total of 60 Wistar rats were used. The rats were irradiated with a single dose of 50 Gy using a Leksell Gamma Knife device. Bevacizumab and ramipril were administered in the prophylactic protocol (starting the first day of SRS) and in the therapeutic protocol (starting the fourth week of SRS). Their usage was continued until 12 weeks, and the right frontal lobes of the rats were examined histologically (hematoxylin and eosin stain) and immunohistochemically (hypoxia-inducible factor [HIF]-1α, VEGF, and CD31 antibody expression). Results: The expression of VEGF, HIF-1α, and CD31 had significantly increased at 12 weeks after SRS compared with the control group. The addition of bevacizumab or ramipril to SRS significantly mitigated the histological severity of radiation injury and the expression of VEGF, HIF-1α, and CD31. However, the prophylactic use of bevacizumab and ramipril seemed to be more effective than therapeutic administration. Our results also revealed that the greatest benefit was achieved with the use of prophylactic administration of bevacizumab compared with other treatment protocols. Conclusions: Ramipril might be a promising agent for patients with radionecrosis. Clinical studies are required to investigate the effective and safe doses of ramipril, which is an inexpensive, well-tolerated drug that can cross the blood–brain barrier. © 2020 Elsevier Inc

Neurophysiological assessment of an innovative maritime safety system in terms of ship operators' mental workload, stress, and attention in the full mission bridge simulator

The current industrial environment relies heavily on maritime transportation. Despite the continuous technological advances for the development of innovative safety software and hardware systems, there is a consistent gap in the scientific literature regarding the objective evaluation of the performance of maritime operators. The human factor is profoundly affected by changes in human performance or psychological state. The difficulty lies in the fact that the technology, tools, and protocols for investigating human performance are not fully mature or suitable for experimental investigation. The present research aims to integrate these two concepts by (i) objectively characterizing the psychological state of mariners, i.e., mental workload, stress, and attention, through their electroencephalographic (EEG) signal analysis, and (ii) validating an innovative safety framework countermeasure, defined as Human Risk-Informed Design (HURID), through the aforementioned neurophysiological approach. The proposed study involved 26 mariners within a high-fidelity bridge simulator while encountering collision risk in congested waters with and without the HURID. Subjective, behavioral, and neurophysiological data, i.e., EEG, were collected throughout the experimental activities. The results showed that the participants experienced a statistically significant higher mental workload and stress while performing the maritime activities without the HURID, while their attention level was statistically lower compared to the condition in which they performed the experiments with the HURID (all p < 0.05). Therefore, the presented study confirmed the effectiveness of the HURID during maritime operations in critical scenarios and led the way to extend the neurophysiological evaluation of the HFs of maritime operators during the performance of critical and/or standard shipboard tasks

Synchronization and Timing in CMS HCAL

The synchronization and timing of the hadron calorimeter (HCAL) for the Compact Muon Solenoid has been extensively studied with test beams at CERN during the period 2003-4, including runs with 40 MHz structured beam. The relative phases of the signals from different calorimeter segments are timed to 1 ns accuracy using a laser and equalized using programmable delay settings in the front-end electronics. The beam was used to verify the timing and to map out the entire range of pulse shapes over the 25 ns interval between beam crossings. These data were used to make detailed measurements of energy-dependent time slewing effects and to tune the electronics for optimal performance

Energy Response and Longitudinal Shower Profiles Measured in CMS HCAL and Comparison With Geant4

The response of the CMS combined electromagnetic and hadron calorimeter to beams of pions with momenta in the range 5-300 GeV/c has been measured in the H2 test beam at CERN. The raw response with the electromagnetic compartment calibrated to electrons and the hadron compartment calibrated to 300 GeV pions may be represented by sigma = (1.2) sqrt{E} oplus (0.095) E. The fraction of energy visible in the calorimeter ranges from 0.72 at 5 GeV to 0.95 at 300 GeV, indicating a substantial nonlinearity. The intrinsic electron to hadron ratios are fit as a function of energy and found to be in the range 1.3-2.7 for the electromagnetic compartment and 1.4-1.8 for the hadronic compartment. The fits are used to correct the non-linearity of the e pi response to 5% over the entire measured range resulting in a substantially improved resolution at low energy. Longitudinal shower profile have been measured in detail and compared to Geant4 models, LHEP-3.7 and QGSP-2.8. At energies below 30 GeV, the data, LHEP and QGSP are in agreement. Above 30 GeV, LHEP gives a more accurate simulation of the longitudinal shower profile

Design, Performance and Calibration of the CMS Forward Calorimeter Wedges

We report on the test beam results and calibration methods using charged particles of the CMS Forward Calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (3\l |\eta| \le 5), and is essential for large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h \approx 5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as a/\sqrt{E} + b. The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%

Design, Performance, and Calibration of CMS Hadron Endcap Calorimeters

Detailed measurements have been made with the CMS hadron calorimeter endcaps (HE) in response to beams of muons, electrons, and pions. Readout of HE with custom electronics and hybrid photodiodes (HPDs) shows no change of performance compared to readout with commercial electronics and photomultipliers. When combined with lead-tungstenate crystals, an energy resolution of 8\% is achieved with 300 GeV/c pions. A laser calibration system is used to set the timing and monitor operation of the complete electronics chain. Data taken with radioactive sources in comparison with test beam pions provides an absolute initial calibration of HE to approximately 4\% to 5\%