Measurement of photon interaction parameters of high-performance polymers and their composites

WOS: 000438143300012In the present study, commercially important high-performance polymers and their composites have been investigated with respect to photon interactions as means of mass attenuation coefficient (/), mean free path (MFP), half-value layer (HVL), effective atomic number (Z(eff)), effective electron density (N-eff), and energy absorption and exposure buildup factors (EABF and EBF) at different photon energies. For this purpose, sample plates were prepared by extrusion and injection techniques using polyethersulfone, polyetherimide, acrylonitrile butadiene styrene copolymer, polyamide 66, polyphthalamide, and polypropylene copolymers as high-performance polymers and glass and carbon fibers as reinforcement. The (/) s of the materials were measured at 81 and 356keV photon energies to determine MFP, HVL, Z(eff), and N-eff. The theoretical values of these parameters were calculated via ZXCOM, WinXCom and Monte Carlo N-Particle simulation code (MCNP), and a good agreement was obtained between WinXCom-MCNP and MCNP-Exp. Finally, EABFs and EBFs of the samples were calculated up to around 40 MFP in the energy region 0.015-15MeV and significant variations were observed in the continuous energy and MFP regions

SAUNALARIN ÖNEMİ VE TARİHSEL GELİŞİMİ

Doğada, sıcak ve soğuk olmak üzere birbirine zıt iki kutup vardır. Sauna bu tezatların bir uygulama mekanıdır. Sauna, hava ve su vasıtasıyla soğutulan bir sıcak hava banyosudur. Bu banyo ile insan bedeni, soğuk ile sıcak arasındaki doğanın mücadelesini küçük çapta da olsa uygulamasını yaşamaktadır. Buna göre; sauna, sıcak ile soğuğun etkileri arasındaki sonsuz çekişmeyi temsil etmektedir. Sauna, bu iki büyük tesiri ideal bir şekilde bünyesinde toplamaktadır.Bu nedenle, özellikle az güneş gören Finlandiya gibi kuzey ülkelerinde ve Avrupa’da yaygın bir şekilde kullanılan, ancak ekonomik ve kültürel nedenlerden dolayı ülkemizde çok fazla bilinmeyen saunanın tanıtılması amaçlanmıştır.Bu çalışmada, saunaların tarihsel gelişimi, önemi, özellikleri, çeşitleri, sınıflandırılması ve faydaları hakkında literatür taramaları yapılmıştır

An economical and practical procedure of favipiravir synthesis for the treatment of Covid-19

Favipiravir is a wide-spectrum antiviral generic drug that has received large attention during the recent COVID-19 pandemic. While there are synthetic strategies for favipiravir synthesis, economical procedures could contribute to industrial scale synthesis and availability. Accordingly, our efforts focused on an economic and scalable procedure for favipiravir synthesis via the 3,6-dichloropyrazine-2-carbonitrile intermediate obtained from 3-aminopyrazine-2-carboxylic acid. The process afforded favipiravir with 43% yield (from 3,6-dichloropyrazine-2-carbonitrile, by fluorination, hydroxylation, and nitrile hydrolysis reactions) and greater than 99% purity without a chromatographic purification step. Graphical abstract: [Figure not available: see fulltext.]ATABAY Fine Chemicals and Pharmaceutical Compan

Array size and area impact on nanorectenna performance properties

The metal-insulator-metal (MIM) diodes have high speed and compatibility with integrated circuits (IC's) making MIM diodes very attractive to detect and harvest energy for infrared (IR) regime of the electromagnetic spectrum. Due to the fact that small size of the MIM diodes, it is possible to obtain large volume of devices in same unit area. Hence, MIM diodes offer a feasible solution for nanorectennas (nano rectifiying antenna) in IR regime. The aim of this study is to design and develop MIM diodes as array format coupled with antennas for energy harvesting and IR detection. Moreover, varying number of elements which are 4x4, and 40x30 has been fabricated in parallel having 0.040, 0.065 and 0.080 μm2 diode area. For this work we have studied given type of material; Ti-HfO2-Ni, is used for fabricating MIM diodes as a part of rectenna. The effect of the diode array size is investigated. Furthermore, the effect of the array size is also investigated for larger arrays by applying given type of material set; Cr-HfO2-Ni. The fabrication processes in physical vapor deposition (PVD) systems for the MIM diodes resulted in the devices having high non-linearity and responsivity. Also, to achieve uniform and very thin insulator layer atomic layer deposition (ALD) was used. The nonlinearity 1.5 mA/V2 and responsivity 3 A/W are achieved for Ti-HfO2-Ni MIM diodes under low applied bias of 400 mV. The responsivity and nonlinearity of Cr-HfO2-Ni are found to be 5 A/W and 65 μA/V2, respectively. The current level of Cr-HfO2-Ni and Ti-HfO2-Ni is around μA range therefore corresponding resistance values are in 1-10 kΩ range. The comparison of single and 4x4 elements revealed that 4x4 elements have higher current level hence lower resistance value is obtained for 4x4 elements. The array size is 40x30 elements for Cr-HfO2-Ni type of MIM diodes with 40, 65 nm2 diode areas. By increasing the diode area, the current level increases for same size of array. The current level is increased from10 μA to100 μA with increasing the diode area. Therefore resistance decreased in the range of 10 kΩ and nonlinearity is increased from 58 μA/V2 to 65 μA/V2

Highly efficient MIM diodes for NIR and SWIR applications

Metal-insulator-metal (MIM) diodes are highly considered in high frequency applications in form of rectennas for energy harvesting applications due to their fast speed, small size, and ease of fabrication and IC compatibility. In these diodes, insulators are integral part of the device, determining performance parameters. In this study, we have evaluated HfO2 and Al2O3 based MIM diode structures to compare and determine performance parameters, with conversion efficiency being prioritized. The fabrication processes in physical vapor deposition (PVD) systems for the MIM diodes resulted in the devices having high non-linearity and responsivity. Also, to achieve uniform and very thin insulator layer atomic layer deposition (ALD) was used. We implemented the same MIM structure in 10x10 array form, with active area of 200×325 nm2. The efficiency values of same arrays tested with 1200 and 1600 nm wavelength LEDs for 200×325 nm2 diode active area without applying bias. The conversion efficiency value of the HfO2 based structures calculated as 5% for 1200 nm wavelength. These measured values of conversion efficiency are reported for the first time in the literature for MIM diodes in SWIR operation

A low-power CMOS readout IC design for bolometer applications

A prototype of a readout IC (ROIC) designed for use in high temperature coefficient of resistance (TCR) SiGe microbolometers is presented. The prototype ROIC architecture implemented is based on a bridge with active and blind bolometer pixels with a capacitive transimpedance amplifier (CTIA) input stage and column parallel integration with serial readout. The ROIC is designed for use in high (≥ 4 %/K) TCR and high detector resistance Si/SiGe microbolometers with 17x17 μm2 pixel sizes in development. The prototype has been designed and fabricated in 0.25- μm SiGe:C BiCMOS process

Halkımızın teratoloji hakkındaki farkındalığı

Amaç: Bu çalışma ile çevresel etkenlerden kaynaklanan doğumsal bozuklukları ve anormal prenatal gelişmeyi inceleyen ve doğumsal defektleri önlemenin araştırmalarını yapan bilim dalı olan teratoloji hakkında halkımızın neler bildiğini ve konu ile ilgili farkındalıklarını araştırmayı amaçladık. Gereç ve Yöntem: Selçuk Üniversitesi Tıp Fakültesi Hastanesi’ne sağlık hizmeti almak üzere başvuran hasta ve hasta yakınlarından oluşan, yaşları 18 - 79 arasında değişen, eşit sayıda kadın ve erkekten oluşan toplam 400 katılımcıya anket uygulaması yapıldı. Elde edilen veriler ortalama ± standart sapma ve yüzde olarak özetlendi. Bulgular ve Sonuç: Yapılan anket çalışmasında homojen olmayan sonuçlar elde edildi. Bu verilere göre katılımcıların ölü ya da sakat doğumların sebepleri, röntgen, tomografi vb. kullanımının anne karnındaki bebeğe etkileri, ilaçların yan etkilerine dikkat etme, akrabalık derecesinin hastalıklı doğumlara etkisi konularında belirli düzeyde fikir sahibi oldukları saptandı. Anne karnındaki bebeğin hastalıklara karşı en duyarlı olduğu gebelik dönemi hakkında ise yeterli bilgi düzeyine sahip olmadıkları belirlend