Viskoelastik Malzemeden Yapılmış İki Katlı İçi Boş Dairesel Silindirde Eksenel Simetrik Boyuna Dalgaların Dispersiyonu Hakkında

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu makalede, lineer viskoelastik malzemeden yapılmış iki katlı içi boş silindirde eksenel simetrik boyuna dalga yayılımı çalışmasından bahsedilmektedir. Araştırmalar viskoelastisite teorisinin kesin denklemleri kullanılarak parçalı homojen cisim modeli kapsamında yapıldı. Silindir katman materyallerinin bünye denklemleri fraksiyonel eksponansiyel operatörler aracılığıyla tanımlandı ve bu bağıntılar nümerik araştırmalarda kullanıldı. Dispersiyon eğrilerinde problem parametrelerinin değişken değerlerindeki birtakım seçilmiş dispersif sönüm durumları sunulmaktadır ve bu eğriler üzerinde reolojik parametrelerin etkisi tartışılmıştır.The paper deals with the study of axisymmetric longitudinal wave propagation (dispersion) in the bi-layered hollow circular cylinder made of linear viscoelastic materials. The investigations are made within the scope of the piecewise homogeneous body model by utilizing of the exact equations of the linear viscoelasto-dynamics. The layers’ materials of the cylinder are described through fractional exponential operators and this relations are used in the numerical investigations. Dispersion curves are submitted for certain selected dispersive attenuation cases under various values of the problem parameters and the influence of the rheological parameters on these curves are discussed

A compact and sustainable electronic module for silicon photomultipliers

This article presents the development of a cost-effective and efficient electronic module for silicon photomultipliers (SiPM). The electronic module combines essential functionalities, such as a high voltage power supply, a preamplifier, and a signal comparator, into a compact circuit. A high voltage power supply with a range of 30 to 140 V provides a stable bias voltage with 0.01 V accuracy for the SiPMs, while a preamplifier with 40 gain and 250 MHz bandwidth enables signal amplification necessary to extract weak signals. The comparator converts an analogue signal (higher than 8 mV) into TTL (transistor-transistor logic), which makes it easy to process and analyze with digital devices such as microcontrollers or make it possible to send signals over long distances by a cable. The module has been tested using an LYSO scintillator and a SiPM called a micropixel avalanche photodiode (MAPD). It provides a more effective and efficient solution for reading out signals from SiPMs in a variety of applications, delivering reliable and accurate results in real-time.Comment: an article, 9 pages, 6 figure

In Vivo Evaluation of 3D-Printed Silica-Based Bioactive Glass Scaffolds for Bone Regeneration

Bioactive glasses are often designed as porous implantable templates in which newly-formed bone can grow in three dimensions (3D). This research work aims to investigate the bone regenerative capability of silicate bioactive glass scaffolds produced by robocasting in comparison with powder and granule-like materials (oxide system: 47.5SiO2-10Na2O-10K2O-10MgO-20CaO-2.5P2O5, mol.%). Morphological and compositional analyses performed by scanning electron microscopy (SEM), combined with energy dispersive spectroscopy (EDS) after the bioactivity studies in a simulated body fluid (SBF) confirmed the apatite-forming ability of the scaffolds, which is key to allowing bone-bonding in vivo. The scaffolds exhibited a clear osteogenic effect upon implantation in rabbit femur and underwent gradual resorption followed by ossification. Full resorption in favor of new bone growth was achieved within 6 months. Osseous defect healing was accompanied by the formation of mature bone with abundant osteocytes and bone marrow cells. These in vivo results support the scaffold’s suitability for application in bone tissue engineering and show promise for potential translation to clinical assessment

Portable neutron/gamma scintillation detector for status monitoring of accelerator-driven neutron source IREN

Accelerator-driven system (ADS) facilities world-wide opens new opportunities for nuclear physics investigations, so that a high flux of neutrons through spallation reactions can be produced at these facilities. It is known that the measurement, continuous monitoring and optimization of the particle accelerator beam intensity are among the most important actions in the operation of such facilities. Considering this point of view, this paper presents a neutron/gamma counter based on a micropixel avalanche photodiode (MAPD) and a plastic scintillator that monitors the status of the accelerator-driven intense resonance neutron source (IREN) facility by measuring the neutron-gamma intensity in the target hall. The electronics of the modular neutron counter has been designed and developed, including a bias voltage source (up to 130 V), a preamplifier (36 gain) and discriminator (>10 mV) circuit. The last product of MAPD (operation voltage- 55 V, PDE- 33 %, total number of pixels- 136900) was used as a photon readout from a plastic scintillator. The sensitive area of MAPD was 3.7*3.7 mm2 and the size of the plastic scintillator 3.7*3.7*30 mm3. The measurement was carried out in the IREN target hall, where it was necessary to monitor not only high neutron fluxes, but also gamma quanta. The experimental results demonstrated a dependence between the count rate of the detector and the frequency of the accelerator, which ranges from 2 to 50 Hz.Comment: 8 pages, 7 figure

Formulation of a mathematical problem and methods for solving the development of antistatic clothing for protection from elevated temperatures

The article is devoted to the study and development of a mathematical model of the process of electrification of textile materials in the system "man - clothing - environment" in hot climatic conditions. The phenomenon of static electrification, which occurs in the processes of manufacturing textile materials and products from them, as well as during the operation of finished products, leads to a decrease in the quality of products, causes inconvenience in work, and when an electric discharge occurs, it poses a threat to human life. Such interactions of elements in the "person - clothing - environment" system such as friction, compression, tension, shear increase the contact area of two media, and depending on the rate of these processes, they enhance or weaken metabolic processes, which contributes to an increase in the maximum static charge generated on contacting surfaces. temperature values for special clothing of limited length at the nodal points. At the same time, the number of nodal points is 1601, the number of connected elements is 800. In the area of temperature distribution along the length of the garment, in four different versions, it was found that in the I – version , in the II – version  , in the III – version , in the IV – version , in the V – version , in the VI - version, the length of the clothes in this area increased by 10% compared to the length of the clothes in the II – version

Performance of a plastic scintillator developed using styrene monomer polymerization

This paper presents a newly developed plastic scintillator produced in collaboration with Turkiye Energy, Nuclear and Mineral Research Agency (TENMAK). The scintillator is manufactured using thermal polymerization of commercially available styrene monomer. The absorption spectrum of the scintillator exhibited two absorption bands at 225 nm and 340 nm, with an absorption edge observed at 410 nm. The wavelength of the emitted light was measured in the range of 400-800 nm, with a maximum intensity at 427 nm. Monoenergetic electrons from the 137Cs source were used to evaluate the characteristics of the new scintillator, particularly its light yield. As the light readout the MAPD-3NM type silicon photomultiplier array (4 x 4) with an active area of 15 x 15 mm2, assembled using single MAPDs with an active area of 3.7 x 3.7 mm2, was used. The light yield of the scintillator was determined to be 6134 photons/MeV. In addition, the efficiency of the scintillator for gamma rays with an energy of 662 keV was found to be approximately 1.8 %. A CmBe neutron source was employed to evaluate its fast neutron detection performance. However, neutron/gamma discrimination using pulse shape discrimination (charge integration) method was not observed. The results demonstrate the potential of a newly produced plastic scintillator for various applications, particularly in radiation monitoring and detection systems.Comment: 7 pages, 7 figure

Publisher Correction:Discovery of rare variants associated with blood pressure regulation through meta-analysis of 1.3 million individuals (Nature Genetics, (2020), 52, 12, (1314-1332), 10.1038/s41588-020-00713-x)

In the version of this article originally published, the e-mail address of corresponding author Patricia B. Munroe was incorrect. The error has been corrected in the HTML and PDF versions of the article

Discovery of rare variants associated with blood pressure regulation through meta-analysis of 1.3 million individuals

Correction: Volume53, Issue5 Page 762-762 DOI: 10.1038/s41588-021-00832-z Published MAY 2021Genetic studies of blood pressure (BP) to date have mainly analyzed common variants (minor allele frequency > 0.05). In a meta-analysis of up to similar to 1.3 million participants, we discovered 106 new BP-associated genomic regions and 87 rare (minor allele frequencyPeer reviewe

Experience in International Cooperation on Organization of Anti-Epidemic Measures by Health Care Institutions under COVID-19 Pandemic in the Republic of Uzbekistan

The results of the joint work of a panel of experts from Rospotrebnadzor and healthcare professionals of the Republic of Uzbekistan on organizing activities to counter the spread of the SARS-CoV-2 virus are described in the paper.The goal of the study was to determine the main driving forces of COVID-19 spread in the Republic of Uzbekistan and develop an action plan to reduce the incidence of coronavirus infection caused by the SARS-CoV-2 virus.Materials and methods. The organization of work in 14 health care institutions in Tashkent and Samarkand, as well as in Tashkent and Samarkand Regions, was analyzed: in 7 laboratories, 6 hospitals and 1 polyclinic. The routes for the movement of personnel, the demarcation of green and red zones, the features of disinfection and the use of personal protective equipment were studied. Attention is drawn to the diagnosis of COVID-19, the use of therapy aimed at reducing the period of virus shedding, the criteria for lifting quarantine restrictions for patients.Results and discussion. The main factors in the organization of work of institutions that contribute to the spread of COVID-19 among medical personnel and the population have been identifed: the lack of equipped gateways between the red and green zones with the accessibility of adequate disinfection, the wrong choice of personal protective equipment, monitoring of contact persons for 10 days, discharge from hospitals based on clinical improvement. The incorrect use of antiviral therapy, the lack of differentiated approaches to the selection of optimal regimens have been noted. Proposals are formulated for organizing the work of healthcare institutions, taking into account the requirements of biological safety. The introduction of targeted measures in addition to those previously adopted has led to a signifcant improvement in the epidemic situation: the total number of active cases in the Republic of Uzbekistan, despite the increase in testing volumes, decreased from 3,686 people on August 23 to 2335 on October 27. Towards December 20, 2020, 97 % of patients recovered completely. All diagnostic triage centers in the Republic of Uzbekistan are closed due to the absence of patients with COVID-19, most of the country’s medical institutions previously re-profled for patients with coronavirus infection have returned to the routine operations