Ka-band full duplex system with electrical balance duplexer for 5G applications using SiGe BiCMOS technology

The current dominating communication system is 4G. However, with the increase in the data rate and in the number of users in the world, the 4G communication system has started to saturate and couldn’t manage to keep up with user demands and there is less room for progress at 4G systems. In search of finding a system that covers the future interests of users, a new communication scheme is being processed as 5G. The next generation systems require wider bandwidth, high spectral efficiency, and less latency. For these goals, designs with higher frequency and full-duplex operation mode have been started to gain attention. Developments in SiGe HBT technologies -higher fT and fmax- make them suitable for these challenges. Considering these trends which lead to the future of communication systems, in this thesis the design of Ka-band (25-32GHz) SiGe full duplex system with electrical balance duplexer for 5G applications is presented. This system is created by integrating. a duplexer, an LNA, and a PA. The electrical balance duplexer is realized by a hybrid transformer and a balancing network. The impedance of the antenna is mimicked by tuning the balancing network to provide high isolation between transmitter and receiver blocks. All the ports have better than 10dB return loss. Duplexer provides measured 39dB peak isolation at 28GHz, with 3.8dB insertion loss from the transmitter to the antenna and 4.7dB insertion loss from the antenna to receiver. The LNA achieves the measured gain of 15dB, NF of 3.5dB and OP1dB of 13.5dBm at 28GHz by including an input and an output BALUN transformer. The PA provides measured gain of 17dB and OP1dB of 14dBm at 28GH

Enhanced granular medium-based tube press hardening

Active and passive control strategies of internal pressure for hot forming of tubes and profiles with granular media are described. Force transmission and plastic deformation of granular medium is experimentally investigated. Friction between tube, granular medium and die as also the external stress field are shown to be essential for the process understanding. Wrinkling, thinning and insufficient forming of the tube establishes the process window for the active pressure process. By improving the punch geometry and controlling tribological conditions, the process limits are extended. Examples for the passive pressure process reveal new opportunities for hot forming of tubes and profiles.Comment: 4 pages, 11 figure

Impact of Elaeagnus angustifolia flour added to bio-yogurt on probiotic survival and monitoring of in vitro acid tolerance in synthetic gastric fluid

Abstract The present study aimed to investigate the effect of oleaster flour on Lactobacillus acidophilus, L. delbrueckii subsp. bulgaricus, and Bifidobacterium animalis subsp. lactis in probiotic yogurt during its storage period and whether oleaster flour has a protective effect against gastric fluid for these probiotic bacteria. For that purpose, the effect of oleaster flour at different doses (1%, 2%, and 3% w/v) on the titratable acidity, pH, and microbiological properties was investigated throughout cold storage. In addition, on the first day of storage, in vitro tolerance of probiotics in pH adjusted to (pH 2.0-ph 4.0) simulated gastric fluid was investigated for 1, 60, 120, and 180 min. Yogurt with a higher dosage (2%-3%) of oleaster flour had a higher pH and lower titratable acidity. Moreover, the addition of 3% oleaster flour showed a preservative effect on L. acidophilus, L. delbrueckii subsp. bulgaricus and B. animalis subsp. lactis during storage. On the first day of storage in pH 4.0 for synthetic gastric fluid, in vitro acid tolerance of all probiotics showed stability for 180 minutes. Also, at pH 2.0 SGF, B. animalis subsp. lactis was below the detectable limit in the control and 1% of groups. However, the 2% and 3% groups showed nearly 3 log cfu/g viability at the end of 180 min. These positive effects were related to the buffering effect of the oleaster peel. Thus, these results could prove that oleaster flour can be used for the production of bio-yogurt

Deep drawing of high-strength tailored blanks by using tailored tools

In most forming processes based on tailored blanks, the tool material remains the same as that of sheet metal blanks without tailored properties. A novel concept of lightweight construction for deep drawing tools is presented in this work to improve the forming behavior of tailored blanks. The investigations presented here deal with the forming of tailored blanks of dissimilar strengths using tailored dies made of two different materials. In the area of the steel blank with higher strength, typical tool steel is used. In the area of the low-strength steel, a hybrid tool made out of a polymer and a fiber-reinforced surface replaces the steel half. Cylindrical cups of DP600/HX300LAD are formed and analyzed regarding their formability. The use of two different halves of tool materials shows improved blank thickness distribution, weld-line movement and pressure distribution compared to the use of two steel halves. An improvement in strain distribution is also observed by the inclusion of springs in the polymer side of tools, which is implemented to control the material flow in the die. Furthermore, a reduction in tool weight of approximately 75% can be achieved by using this technique. An accurate finite element modeling strategy is developed to analyze the problem numerically and is verified experimentally for the cylindrical cup. This strategy is then applied to investigate the thickness distribution and weld-line movement for a complex geometry, and its transferability is validated. The inclusion of springs in the hybrid tool leads to better material flow, which results in reduction of weld-line movement by around 60%, leading to more uniform thickness distribution

Low-noise amplifiers for w-band and d-band passive imaging systems in SiGe BiCMOS technology

In this paper, two wideband and low power mmwave LNAs implemented in a 0.13μm SiGe BiCMOS technology are presented. The W-band LNA has 22.3 dB peak gain, 17 GHz 3-dB bandwidth (BW) and 8 mW of power consumption whereas the D-Band LNA achieves 25.3 dB peak gain, 44 GHz 3-dB BW while consuming 30 mW of power. Input and output of the LNAs are wideband matched to 50 Ω in their respective frequency bands. Using the measured gains, the effective noise bandwidths are calculated to be 33.8 GHz for the W-band and 58.9 GHz for the Dband LNAs. Measurement results indicate that the LNAs are suitable for low power and wideband radiometer systems

In a real-life setting, direct-acting antivirals to people who inject drugs with chronic hepatitis c in Turkey

Background: People who inject drugs (PWID) should be treated in order to eliminate hepatitis C virus in the world. The aim of this study was to compare direct-acting antivirals treatment of hepatitis C virus for PWID and non-PWID in a real-life setting. Methods: We performed a prospective, non-randomized, observational multicenter cohort study in 37 centers. All patients treated with direct-acting antivirals between April 1, 2017, and February 28, 2019, were included. In total, 2713 patients were included in the study among which 250 were PWID and 2463 were non-PWID. Besides patient characteristics, treatment response, follow-up, and side effects of treatment were also analyzed. Results: Genotype 1a and 3 were more prevalent in PWID-infected patients (20.4% vs 9.9% and 46.8% vs 5.3%). The number of naïve patients was higher in PWID (90.7% vs 60.0%), while the number of patients with cirrhosis was higher in non-PWID (14.1% vs 3.7%). The loss of follow-up was higher in PWID (29.6% vs 13.6%). There was no difference in the sustained virologic response at 12 weeks after treatment (98.3% vs 98.4%), but the end of treatment response was lower in PWID (96.2% vs 99.0%). In addition, the rate of treatment completion was lower in PWID (74% vs 94.4%). Conclusion: Direct-acting antivirals were safe and effective in PWID. Primary measures should be taken to prevent the loss of follow-up and poor adherence in PWID patients in order to achieve World Health Organization’s objective of eliminating viral hepatitis

Haddeli şekillendirilmiş ürünlerin soğuk şekilendirme etkilerini içererek değerlendirilmesi.

Roll-forming is an efficient sheet forming process that is used in manufacturing long parts with constant cross-section. The theoretical, experimental and numerical analyses of the process are limited since the sheet takes a complex 3D shape during the process. In this study proper finite element method models to simulate the roll-forming process are examined both numerically and experimentally. In addition, the applicability of 2D plane strain models to the simulation of the process is investigated. To reveal the deformation of the sheet, important geometrical parameters of the sheet and the rollers are introduced. The effect of these parameters on the strain hardening and deformation of the sheet is analyzed at distinct parts of the sheet that undergoes different types of deformations. Having revealed the deformation mechanisms, the assumptions behind the theoretical knowledge is criticized. The mentioned studies are verified with a case study in which a roll-formed product is analyzed under service loads. The manufacturing of the product and service load application are simulated and the results are compared with the experiments. In addition, effects of cold forming on the behaviour of the product under service loads are examined. It is concluded that under some conditions, 2D plane strain simulations can be used to predict the strain hardening in the material that occurs during roll-forming and this hardening has a considerable effect on the response of the material under loading.M.S. - Master of Scienc

Investigation of the mechanical properties of rhodium nanowires by molecular dynamics simulations

Nanotellerin, aynı cins atomlardan oluşmuş iri hacimli (bulk) malzemelere göre çok daha farklı elektronik, optik ve yapısal özellikler gösterdiği bilinmektedir. Bu nedenle nanotellerin kullanıldığı yeni elektro-mekanik cihazların tasarımı ve üretimi bu sistemlerin dayanım, esneklik ve kırılma gibi mekanik özelliklerinin bütünüyle anlaşılmasını gerektirmektedir. Ayrıca, sonlu ve boyuta bağlı mekanik özeliklerinin karakterizasyonu öne sürülen teorik önermelerin geçerliliğinin anlaşılması için de önemli bir dayanaktır. Bu çalışma ile çeşitli alanlarda kullanımı yaygın olan rodyum nanotellerinin mekanik özelliklerinin bilgisayar destekli moleküler dinamik simülasyonları ile belirlenmesi ve deformasyon süreci ile ilişkisinin yorumlanması hedeflenmiştir. Rh nanotellerinin gerilim-gerinim davranışının bulk sisteme kıyasla radikal değişikliğe sahip olduğu görülmüş olup nanotellerin mekanik özelliklerinin belirlenmesinde germe oranına kıyasla boyut etkilerinin söz sahibi olmasının yanında düşük boyutlarda yüksek germe oranı kullanıldığında daha sünek ve kırılmaya dayanıklı Rh nanotellerin elde edilebileceği gözlenmiştir. Nanotelin mekanik özelliklerinin anlaşılması ve karakterizasyonu üzerine odaklanarak, deformasyon mekanizması ile ilişkisini ortaya koyması planlanan bu çalışma, benzer sistemler üzerine yapılacak deneysel ve teorik önermelere zemin oluşturacaktır.Nanowires are known to exhibit much different electronic, optical and structural properties than their bulk counterparts. The design and manufacture of new electro-mechanical devices using nanowires require a full understanding of the mechanical properties of these systems, such as strength, flexibility and fracture. In addition, the characterization of the finite and size dependent mechanical properties is an important basis for understanding the validity of the proposed theoretical propositions. The aim of this study is to determine the mechanical properties of rhodium (Rh) nanowires, which are widely used in various fields, by means of computer-aided molecular dynamic simulations and to interpret their relationship to the deformation process. It has been observed that the stress-strain behavior of Rh nanowires radically different with respect to the bulk material. It is observed that the size of nanowire is more effective to determine desired mechanical properties with respect to the strain rate and the ductile and break-proof Rh nanowires can be obtained by using the high strain rate and small size of nanowires. This study focuses on the understanding and characterization of the mechanical properties of nanowires and is intended to form the basis for experimental and theoretical statements on similar systems