RF Amplification and Filtering Techniques for Cellular Receivers

The usage of various wireless standards, such as Bluetooth, Wi-Fi, GPS, and 4G/5G cellular, has been continually increasing. In order to utilize the frequency bands efficiently and to support new communication standards with lower power consumption, lower occupied volume and at reduced costs, multimode transceivers, software defined radios (SDRs), cognitive radios, etc., have been actively investigated. Broadband behavior of a wireless receiver is typically defined by its front-end low-noise amplifier (LNA), whose design must consider trade-offs between input matching, noise figure (NF), gain, bandwidth, linearity, and voltage headroom in a given process technology. Moreover, monolithic RF wireless receivers have been trending toward high intermediatefrequency (IF) or superhetrodyne radios thanks to recent breakthroughs in silicon integration of band-pass channel-select filters. The main motivation is to avoid the common issues in the currently predominant zero/low-IF receivers, such as poor 2nd-order nonlinearity, sensitivity to 1/f (i.e. flicker) noise and time-variant dc offsets, especially in the fine CMOS technology. To avoid interferers and blockers at the susceptible image frequencies that the high-IF entails, band-pass filters (BPF) with high quality (Q) factor components for sharp transfer-function transition characteristics are now required. In addition, integrated low-pass filters (LPF) with strong rejection of out-of-band frequency components are essential building blocks in a variety of applications, such as telecommunications, video signal processing, anti-aliasing filtering, etc. Attention is drawn toward structures featuring low noise, small area, high in-/out-of-band linearity performance, and low-power consumption. This thesis comprises three main parts. In the first part (Chapters 2 and 3), we focus on the design and implementation of several innovative wideband low-noise (transconductance) amplifiers [LN(T)A] for wireless cellular applications. In the first design, we introduce new approaches to reduce the noise figure of the noise-cancellation LNAs without sacrificing the power consumption budget, which leads to NF of 2 dB without adding extra power consumption. The proposed LNAs also have the capability to be used in current-mode receivers, especially in discrete-time receivers, as in the form of low noise transconductance amplifier (LNTA). In the second design, two different two-fold noise cancellation approaches are proposed, which not only improve the noise performance of the design, but also achieve high linearity (IIP3=+4.25 dBm). The proposed LN(T)As are implemented in TSMC 28-nm LP CMOS technology to prove that they are suitable for applications such as sub-6 GHz 5G receivers. The second objective of this dissertation research is to invent a novel method of band-pass filtering, which leads to achieving very sharp and selective band-pass filtering with high linearity and low input referred (IRN) noise (Chapter 4). This technique improves the noise and linearity performance without adding extra clock phases. Hence, the duty cycle of the clock phases stays constant, despite the sophisticated improvements. Moreover, due to its sharp filtering, it can filter out high blockers of near channels and can increase the receiver’s blocker tolerance. With the same total capacitor size and clock duty cycle as in a 1st-order complex charge-sharing band-pass filter (CS BPF), the proposed design achieves 20 dB better out-of-band filtering compared to the prior-art 1st-order CS BPF and 10 dB better out-of-band filtering compared to the conventional 2nd-order C-CS BPF. Finally, the stop-band rejection of the discrete-time infinite-impulse response (IIR) lowpass filter is improved by applying a novel technique to enhance the anti-aliasing filtering (Chapter 5). The aim is to introduce a 4th-order charge rotating (CR) discrete-time (DT) LPF, which achieves the record of stop-band rejection of 120 dB by using a novel pseudolinear interpolation technique while keeping the sampling frequency and the capacitor values constant

Investigation of Relationship between Level of Awareness around Health, Safety and Environment Management System and Its Effects on Safety Climate and Risk Perception by Employees in an Iran Oil Refinery, 2015

Special attention of and oil, gas and petrochemical large corporation in the world to the HSE management system is due to its importance in the designing and development of products, services and processes by considering its health, safety and environment requirements. Staff's perception of the existing job risks has a significant impact on their safe behavior at work. This study was conducted to determine the relationship between safety climate and staff's perception of risk with an awareness level among employees of the HSE management system in an oil refinery in Kermanshah. The study population was employees in one of the oil refineries in Iran. After designing and questionnaire psychometric assessment of staff knowledge of HSE management system (Cronbach's alpha was 0.9 and its validity was assessed by certified professionals), Loughborough safety climate questionnaire and Flin risk perception questionnaire were used. Data analysis was performed using SPSS V22 software. Results showed that the relationship between safety climate and awareness level of the HSE management system; also the relationship between safety climate and perception of risk was also getting significant. However, the relationship between perception of risk and awareness level of the HSE management system was not significant. The results of this study showed a moderate awareness of HSE Management System in refinery workers. In this regard, appropriate and proper management policy should be committed to improving the situation. The results of this study is a profile the situation of safety climate in the refinery, which can be used as an indicator for the development of preventive policies and evaluate the performance of the organization's safety and the results of the safety improvement organization

Distributed bidding strategy for an aggregator valuing uncertain prosumers in energy and ancillary service markets

Aggregators have an influential intermediary role to exploit the flexibility of prosumers like smart homes for procuring the required capacity of ancillary services to support power systems. Local generation and consumption uncertainties of prosumers affect their cost reduction objectives which in turn have a significant impact on the flexibility capacity provided by them. So, towards boosting the operational flexibility capacity in the market, the aggregator’s bidding and remuneration frameworks should devise a valuing scheme of prosumers considering this impact to induce positive incentives relieving capacity uncertainties. This scheme, simultaneously, should observe data privacy concerns. To this end, this paper proposes a day-ahead distributed bidding strategy framework for an aggregator to participate in regulation and energy markets using a new rewarding scheme derived from a flexibility certainty valuing approach. This framework is developed within the Benders decomposition method, in which the aggregator performs valuing of prosumers in the master problem through their implicit information extracted from home energy management systems modeled in the subproblems. The performance of the framework to appropriately reward prosumers is presented through numerical results for an illustrative case study

Investigation of Relationship between Level of Awareness around Health, Safety and Environment Management System and Its Effects on Safety Climate and Risk Perception by Employees in an Iran Oil Refinery, 2015

Special attention of and oil, gas and petrochemical large corporation in the world to the HSE management system is due to its importance in the designing and development of products, services and processes by considering its health, safety and environment requirements. Staff's perception of the existing job risks has a significant impact on their safe behavior at work. This study was conducted to determine the relationship between safety climate and staff's perception of risk with an awareness level among employees of the HSE management system in an oil refinery in Kermanshah. The study population was employees in one of the oil refineries in Iran. After designing and questionnaire psychometric assessment of staff knowledge of HSE management system (Cronbach's alpha was 0.9 and its validity was assessed by certified professionals), Loughborough safety climate questionnaire and Flin risk perception questionnaire were used. Data analysis was performed using SPSS V22 software. Results showed that the relationship between safety climate and awareness level of the HSE management system; also the relationship between safety climate and perception of risk was also getting significant. However, the relationship between perception of risk and awareness level of the HSE management system was not significant. The results of this study showed a moderate awareness of HSE Management System in refinery workers. In this regard, appropriate and proper management policy should be committed to improving the situation. The results of this study is a profile the situation of safety climate in the refinery, which can be used as an indicator for the development of preventive policies and evaluate the performance of the organization's safety and the results of the safety improvement organization

Fabrication of TiFe-Based Electrodes Using High-Energy Ball Mill with Mn Additive for NiMH Batteries

Binary and ternary (with the addition of Mn) TiFe-based intermetallic compound powders were fabricated by high energy ball milling, and their electrochemical behavior as negative electrodes was investigated in 6M-KOH. X-ray diffraction exhibited the single phase of nanostructured binary and ternary TiFe-based crystallites after 20 h of milling followed the amorphous phase formation. Addition of Mn increased peak broadening and in turn decreased the nanocrystallite size of TiFe. Electrode properties of 20, 40, 60, and 70 h binary milled products showed that the discharge capacity of the 60 h one offered a maximum discharge capacity of ~169 mAhg−1. Although substitution of Mn for Ti (Ti1−xFeMnx, x = 0.1, 0.2) caused a decrease in initial discharge capacity, the periodic stability increased compared to the binary TiFe and ternary TiFe1-xMnx (x = 0.1, 0.2). The ternary Ti0.9FeMn0.1 electrode maintained ~53% of its initial discharge capacity after five cycles of charge–discharge; this was just 28% in the case of binary TiFe electrode

Laser powder bed fusion of Alumina/Fe–Ni ceramic matrix particulate composites impregnated with a polymeric resin

Additive Manufacturing (AM) plays a key role in meeting the vital demands of Industry. The AM industry needs the range of applicable materials to be expanded by conducting research on novel ones. In the present investigation, alumina/Fe–Ni (steel) ceramic matrix particulate composite was fabricated employing laser powder bed fusion (LPBF) additive manufacturing (AM) technology. The quality of the printed samples was associated with the LPBF process parameters, which were optimized for this process. In general, the fabricated samples showed a microstructure of alumina matrix with uniform distribution of steel (Fe–Ni) particles. The as-printed samples exhibited pores. Thus, they were subjected to a sintering heat treatment cycle under an inert atmosphere. Although the sintering cycle considerably increased the average Vickers hardness, pores were not eliminated entirely. Therefore, polymer impregnation of the as-sintered samples was carried out to reduce porosities and microcracks. The mercury porosimeter showed that the porosity decreased sequentially after sintering and polymer impregnation. In addition, mechanical investigations revealed that the polymer impregnation improved the compressive strength of the sintered samples (from 56 to 120 MPa). Alumina-based materials find wide applications in various fields, including the manufacturing of electronic components, cutting tools, biomedical implants, and catalyst converters, owing to their low density, high hardness, wear and corrosion resistance, and biocompatibility. This study presents a viable approach for the fabrication of these materials, with developed samples exhibiting promising properties. The study emphasizes the potential of additive manufacturing as an approach for the fabrication of ceramic matrix composites reinforced with metallic particulates in future research

Correlates of impulsive and hostile behavior in patients with borderline personality disorder and bipolar II disorder

Introduction: Patients with borderline personality disorder (BPD) suffer from a higher degree of impulsive and hostile behavior, compared with other psychiatric disorders. On the other hand, the impulsive behavior in these patients is different from the patients with type II bipolar disorder (BMD II). This study aimed to investigate the differences between patients with BPD and patients with bipolar disorder in the aggressiveness and impulsivity scales. Methods: A descriptive-analytical study through a convenience sampling method was conducted on 117 patients with BPD (30 patients) and BMD II (87 patients) who completed the Buss and Perry’s Aggression Questionnaire as well as the Barratt Impulsiveness Scale. The obtained data was analyzed in SPSS using Student’s t-test, and its results were considered significant at P < 0.05 level. Results: The two groups were significantly different in terms of attention and cognitive complexity of Barratt Impulsiveness Scales, hostility, physical aggression, as well as in the total score of Buss and Perry’s aggression and hostility questionnaire, in which the scores in patients with BMD in the above-mentioned scales were higher, compared with the BPD and finally, the marital status variable was significantly correlated with age, physical aggression, anger, anxiety, cognitive complexity, and perseverance.Conclusion: The patients with BMD II experienced a higher degree of excitement in terms of hostility, violence and impulsivity measures; it is also different from the patients with borderline disorder in terms of type of aggressiveness

COMPARING STRESS LEVEL IN PARENTS OF PREMATURE NEONATES HOSPITALIZED IN NEONATAL INTENSIVE CARE UNITS [NICU] IN EDUCATIONAL-MEDICAL CENTERS OF AHVAZ

Objective: birth of premature and low birth weight baby is the most underlying factor of mortality during the first year of life. Paying attention to social-mental effective aspects of birth of premature baby in parents is also important. The main objective of this study is to compare the stress of fathers and mothers of premature babies hospitalized in NICUs of Ahvaz Educational-Medical Centers. Method: the study is a descriptive-analytical research and the statistical population consists of all families of premature babies hospitalized in Abuzar and Imam Hospitals. 192 people of these families were selected as sample based on number of beds in each unit of hospital. The data collection was done using two questionnaires of demographic information and Parent Stressor Scale: neonatal intensive care unit [PSS: NICU]. Validity and reliability of the instrument was confirmed in similar studies. Data analysis was done using SPSS software. Results: mean value and standard deviation [SD] of environmental factor is equal to [3.30±0.514] in fathers and to [3.81±0.532] in mothers. Independent t-test showed also significant difference between mothers and fathers [p<0.0001]. However, mean value and SD of the appearance and behavior of baby and parent role change showed respectively no significant difference between them using independent t-test [p=0.206] [p=0.175]. Conclusion: after birth of premature babies and hospitalization in NICU, parents experience high level of stress. Hence, it is necessary for the medical personnel to pay specific attention to the parents in addition to provide care for the babies. Key words: premature Neonates, NICU, family, stres

Wpływ stosowania dożylnej N-acetylocysteiny w zapobieganiu migotaniu przedsionków po pomostowaniu aortalno-wieńcowym: badanie z randomizacją i grupą kontrolną prowadzone metodą podwójnie ślepej próby

Background: Atrial fibrillation (AF) is one of the most frequently occurring dysrhythmias after coronary artery bypass graft (CABG) surgery. Aim: The aim of this study was to evaluate the effect of intravenous N-acetylcysteine (NAC) on the prevention of AF after CABG surgery. Methods: In a double-blind, randomised controlled trial, a total of 150 patients who were scheduled for on-pump CABG surgery were randomly assigned into two groups. In group A, patients received an intravenous NAC infusion (50 mg/kg) after induction of anaesthesia. These patients additionally received two intravenous doses of NAC on postoperative days 1 and 2. Patients in group B received normal saline (as a placebo) with the same volume, during the same time interval. During the first three days after surgery, postoperative AF (POAF) was assessed by continuous electrocardiogram monitoring; serum high-sensitivity C-reactive protein (hsCRP) level was also assessed before and three days after surgery. Results: During follow-up, 17 patients (17/141, 12.1%) developed POAF. POAF occurred in four (5.6%) patients in the NAC group and 13 (18.8%) patients in the placebo group (OR 0.23; 95% CI 0.08–0.82; p = 0.02). In the multivariable logistic regression analysis, the only predictor of AF after CABG surgery was the use of NAC (OR 0.21; 95% CI 0.06–0.73; p = 0.01). Also, the hsCRP level trend in the NAC group was different from the trend in the control group (group time interaction or interaction effect) (p < 0.001). Conclusions: It seems that perioperative intravenous NAC therapy can be effectively used to reduce inflammation and the incidence of POAF after CABG surgery. The clinical trial registration number: IRCT2015040921669N1Wstęp: Migotanie przedsionków (AF) jest jednym z najczęstszych zaburzeń rytmu u chorych po zabiegu pomostowania aortalno-wieńcowego (CABG). Cel: Badanie przeprowadzono w celu oceny wpływu stosowania N-acetylocysteiny (NAC) w postaci dożylnej na zapobieganie AF po zabiegu CABG. Metody: W badaniu z randomizacją i grupą kontrolną przeprowadzonym metodą podwójnie ślepej próby 150 chorych zakwalifikowanych do zabiegu CABG z wykorzystaniem krążenia pozaustrojowego (on-pump) przydzielano losowo do jednej z dwóch grup. W grupie A po indukcji znieczulenia podawano chorym NAC w infuzji dożylnej (50 mg/kg). Chorzy z tej grupy otrzymywali dwie dodatkowe dawki dożylne NAC w 1. i 2. dniu po zabiegu. Pacjentom z grupy B podawano roztwór soli fizjologicznej (jako placebo) w takiej samej objętości i w takich samych odstępach czasowych. Przez pierwsze 3 dni po zabiegu stosowano ciągłe monitorowanie elektrokardiograficzne w celu wykrycia ewentualnych epizodów pooperacyjnego AF (POAF). Ponadto przed zabiegiem i 3 dni po nim oznaczono stężenie białka C-reaktywnego metodą wysokoczułą (hsCRP). Wyniki: W okresie obserwacji POAF wystąpiło u 17 chorych (17/141; 12,1%). Pooperacyjne AF wykryto u 4 chorych z grupy NAC (5,6%) i u 13 pacjentów z grupy placebo (18,8%); (OR 0,23; 95% CI 0,08–0,82; p = 0,02). W wieloczynnikowej analizie regresji logistycznej jedynym parametrem predykcyjnym AF po zabiegu CABG było stosowanie NAC (OR 0,21; 95% CI 0,06–0,73; p = 0,01). Stwierdzono również różnicę w zakresie trendu stężeń hsCRP między grupą NAC a grupą kontrolną (interakcja czasowa lub efekt interakcji) (p < 0,001). Wnioski: Uzyskane wyniki sugerują, że podawanie NAC w postaci dożylnej w okresie okołooperacyjnym może być skuteczne w ograniczaniu stanu zapalnego i zmniejszaniu częstości POAF po CABG. Numer rejestracyjny badania klinicznego: IRCT2015040921669N1