Multi-Band Outphasing Power Amplifier Design for Mobile and Base Stations

New generations of wireless communication systems require linear efficient RF power amplifiers (PAs) for higher transmission data rates and longer battery life. On the contrary, conventional PAs are normally designed for peak efficiency under maximum output power (Pout). Thus, in power back-off, the overall efficiency degrades significantly and the average efficiency is much lower than the efficiency at maximum Pout. Chireix outphasing PA, also called LINC (Linear amplification using Non-linear Components), is one of the most promising techniques to improve the efficiency at power back-off. In this method, a variable envelope input signal is first decomposed into two constant-envelope phase-modulated signals and then amplified using two highly efficient non-linear PAs. The output signals are combined preferably in a loss-less power combiner to build the desired output signal. In this way, the PA exhibits high efficiency with good linearity. In this thesis, first we analyze a complex model of outphasing combiner considering its nonidealities such as reflection and loss in transmission lines (TL). Then we propose a compact model with analytical formula that is validated through several comparative tests using ADS and Spectre RF. Furthermore, we analyze the effect of reactive load in Chireix combiner with stubs (a parallel inductor and capacitor), while distinguishing between its capacitive and inductive parts. It is demonstrated that only the capacitive part of the reactive load degrades the performances. Based on this, a new architecture (Z LINC) is proposed where the power combiner is designed to provide a zero capacitive load to the PAs whatever the outphasing angle. The theory describing the operations of the system is developed and a 900 MHz classical LINC and Z-LINC PAs are designed and measured. In addition, a miniaturization technique is proposed which employs λ/8 or smaller TLs instead of conventional λ/4 TLs in outphasing power combiner. This technique is applied to implement a 900 MHz PA using LDMOS power transistors. Besides single-band PAs, dual-band PAs are more and more needed because of an increasing demand for wireless communication terminals to handle multi-band operation. In chapter 5, a new compact design approach for dual-band transmitters based on a reconfigurable outphasing combiner is proposed. The objective is to avoid the cumbersome implementations where several PAs and matching network are used in parallel. The technique is applied to design a dual band PA with a fully integrated power combiner in 90 nm CMOS technology. An inverter-based class D PA topology, particularly suitable for outphasing and multimode operations is presented. The TLs in the combiner, realized using a network of on-chip series inductors and parallel capacitors, are reconfigurable from λ/4 in 1800 MHz to λ/8 in 900 MHz. In order to maximize the efficiency, the on-chip inductors are implemented using high quality factor on chip slab inductors. The measured maximum Pout at 900/1800 MHz are 24.3 and 22.7 dBm with maximum efficiencies of 51% and 34% respectively

On Gm-boosting and cyclostationary noise mechanisms in low-voltage CMOS differential Colpitts VCOs

This paper presents a theoretical study of CMOS differential Colpitts VCOs. The objective is to provide a deep understanding of the different mechanisms that impact the performances of these VCOs, namely the Gm-boosting and cyclostationary noise. The developed methodology and expressions can be used to analyze, optimize and build new VCO topologies. A novel topology with an optimized gate to source (GS) feedback is proposed. It exhibits a figure of merit (FOM) better than -190 dBc/Hz/mW for all the frequency offsets

Evaluación de Silicio e irrigación en tres cultivares de Cártamo

This study was performed to evaluation of interaction of silicon application and irrigation on agronomic and physiologic traits of safflower at 2018 and 2019. The experiment was conducted as a split plot factorial based on randomized complete block design with 3 replications. The irrigation was main factor (0, 2 and 4 times during growth) and the sub-factor were silicon foliar application (at three levels: 0, 1 and 2 mM) and three safflower cultivars (Goldasht, Padideh and Golmehr). The studied traits were: number of seeds per boll and 1000-grain weight, number and weight of boll, number of lateral branches and branch diameter, plant weight and total plant weight, floret yield, grain yield, chlorophyll a and b, proline and antioxidant enzymes. According to results, treatments had significant effects on studied traits at 5 or 1% statistically level. 2 and 3 times irrigation led to 7 and 24% the increasing of seed yield in compare to control, respectively. It was obtained that 1 and 2mM silicon led to 25 and 15% the increase of seed yield in compare to control. Interaction between treatments showed that the highest seed yield (500g per m2) was observed by Goldasht cultivar under 4-time irrigation and 2mM silicon. Therefore, it can be suggested that Goldasht with 2 mM silicon be used to reduce the effects of dehydration.Este estudio se realizó para evaluar la interacción de la aplicación de silicio y el riego en rasgos agronómicos y fisiológicos del cártamo en 2018 y 2019. El experimento se realizó como un factorial de parcela dividida basado en un diseño de bloques completos al azar con 3 repeticiones. El riego fue el factor principal (0, 2 y 4 veces durante el crecimiento) y el subfactor fue la aplicación foliar de silicio (en tres niveles: 0, 1 y 2 mM) y tres cultivares de cártamo (Goldasht, Padideh y Golmehr). Los rasgos estudiados fueron: número de semillas por cápsula y peso de 1000 granos, número y peso de cápsula, número de ramas laterales y diámetro de rama, peso de la planta y peso total de la planta, rendimiento del florete, rendimiento de grano, clorofila ayb, prolina y enzimas antioxidantes Según los resultados, los tratamientos tuvieron efectos significativos en los rasgos estudiados a un nivel estadístico del 5 o 1%. El riego 2 y 3 veces condujo a un aumento de 7 y 24% en el rendimiento de semillas en comparación con el control, respectivamente. Se obtuvo que el silicio de 1 y 2 mM condujo a un aumento de 25 y 15% del rendimiento de la semilla en comparación con el control. La interacción entre tratamientos mostró que el cultivar Goldasht observó un rendimiento de semilla más alto (500 g por m2) bajo riego por 4 tiempos y silicio 2 mM. Por lo tanto, se puede sugerir que se use Goldasht con silicio 2 mM para reducir los efectos de la deshidratación

An Allocation-Routing Optimization Model for Integrated Solid Waste Management

Integrated smart waste management (ISWM) is an innovative and technologically advanced approach to managing and collecting waste. It is based on the Internet of Things (IoT) technology, a network of interconnected devices that communicate and exchange data. The data collected from IoT devices helps municipalities to optimize their waste management operations. They can use the information to schedule waste collections more efficiently and plan their routes accordingly. In this study, we consider an ISWM framework for the collection, recycling, and recovery steps to improve the performance of the waste system. Since ISWM typically involves the collaboration of various stakeholders and is affected by different sources of uncertainty, a novel multi-objective model is proposed to maximize the probabilistic profit of the network while minimizing the total travel time and transportation costs. In the proposed model, the chance-constrained programming approach is applied to deal with the profit uncertainty gained from waste recycling and recovery activities. Furthermore, some of the most proficient multi-objective meta-heuristic algorithms are applied to address the complexity of the problem. For optimal adjustment of parameter values, the Taguchi parameter design method is utilized to improve the performance of the proposed optimization algorithm. Finally, the most reliable algorithm is determined based on the Best Worst Method (BWM)

Simulation and Comparison of Control Methods of Doubly Fed Induction Generator in Energy Conversion System

One of the most applicable methods for utilization of wind energy is the use of doubly fed induction generator (DFIG). This paper presents two various strategies for control of DFIG in wind energy conversion system. Two most common and best control methods are implemented vector control and direct torque control. The studied control methods and their performance have been compared and analyzed based on the results of stimulation. The results indicate the fact that although direct torque control method is a bit slow at the start time; due to less usage of machine parameters, less complexity of control algorithm and improvement of transient response speed of the system, this method presents better performance compared to vector control method

Beneficial Mitochondrial Biogenesis in Gastrocnemius Muscle Promoted by High-Intensity Interval Training in Elderly Female Rats

Objective: Exercise can attenuate mitochondrial dysfunction caused by aging. Our study aimed to compare 12weeks of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the expressionof mitochondria proteins [e.g., AMP-activated protein kinase (AMPK), Estrogen-related receptor alpha (ERRα), p38mitogen-activated protein kinase (P38MAPK), and Peroxisome proliferator-activated receptor gamma coactivator1-alpha (PGC1-α)] in gastrocnemius muscle of old female rats. Materials and Methods: In this experimental study, thirty six old female Wistar rats (18-month-old and 270-310 g) weredivided into three groups: i. HIIT, ii. MICT, and iii. Control group (C). The HIIT protocol was performed for 12 weeks with16-28 minutes (2 minutes training with 85-90% VO2max in high intensity and 2 minutes training with 45-75% VO2max low intensity). The MICT was performed for 30-60 minutes with the intensity of 65-70% VO2max. The gastrocnemius muscle expression of AMPK, ERRα, P38MAPK, and PGC1α proteins were determined by Western blotting. Results: The expression of AMPK (P=0.004), P38MAPK (P=0.003), PGC-1α (P=0.028), and ERRα (P=0.006) in HIITwas higher than C group. AMPK (P=0.03), P38MAPK (P=0.032), PGC-1α (P=0.015), and ERRα (P=0.028) in MICTwas higher than the C group. Also expression of AMPK (P=0.008), P38MAPK (P=0.009), PGC-1α (P=0.020) and ERRα(P=0.014) in MICT was higher than MICT group. Conclusion: It seems that exercise training has beneficial effects on mitochondrial biogenesis, but the HIIT trainingmethod is more effective than MICT in improving mitochondrial function in aging

Geometric morphometric analysis in nine species of genus Hottentotta (Birula 1908) (Arachnida: Scorpiones) from Iran

Hottentotta Birula, 1908 is one of the most widely distributed buthid scorpions, with more than 40described species from Africa, across the Middle East, to India. Currently, this genus is representedby ten morphological species in Iran (H. akbarii, H. jayakari, H. juliae, H. khoozestanus, H.lorestanus, H. navidpouri, H. saulcyi, H. schach, H. sistanensis and H. zagrosensis), all of which areendemic or subendemic in Iran. The members of this genus have not been properly studied from thetaxonomic point of view. A tool that could contribute to scorpions' taxonomic studies is geometricmorphometry, which is defined as the fusion between geometry and biology. In this study, the sizeand shape variations in sternocoxal structure in Hottentotta populations have been examined usingthe geometric morphometric method. The goal was to analyze the isometric size and conformation innine species of Hottentotta. 100 individuals of Hottentotta, collected from different parts of Iranduring 2018-2020, were photographed. Coordinate (x, y) configurations from landmarks wereregistered in sternocoxal structures. Geometric morphometric analyses were performed using Rlanguage. The results clearly showed divergence in the shape and size of sternocoxal structureamong the studied taxa. However, the major shape changes were associated with H. akbarii whichhas a larger size of sternocoxal structure and a narrower sternum, shorter coxa II-III, and longercoxa IV

Catalyzed synthesis and characterization of a novel lignin-based curing agent for the curing of high-performance epoxy resin

In this study, lignin, an aromatic compound from the forestry industry, was used as a renewable material to synthesize a new aromatic amine curing agent for epoxy resin. Firstly, lignin was separated from black liquor and hydroxyl groups were converted to tosyl groups as leaving groups. Then, primary amination was conducted using an ammonia solution at high pressure and temperature, in the presence of a nano-alumina-based catalyst. The structure of the nanocatalyst was confirmed by FT-IR, ICP, SEM, and XPS analyses. According to the FT-IR spectra, a demethylation reaction, the substitution of hydroxyl groups with tosyl groups, and then an amination reaction were successfully performed on lignin, which was further confirmed by the 13 C NMR and CHNS analyses. The active hydrogen equivalent of aminated lignin was determined and three samples with 9.9 wt %, 12.9 wt %, and 15.9 wt % of aminated lignin, as curing agents, were prepared for curing the diglycidyl ether of bisphenol A (DGEBA). The thermal characteristics of the curing process of these epoxy samples were determined by DSC and TGA analyses. Moreover, the mechanical performance of the cured epoxy systems, e.g., the tensile strength and Izod impact strength, were measured, showing that in the presence of 12.9 wt % aminated lignin, the mechanical properties of the aminated lignin-epoxy system exhibited the best performance, which was competitive, compared to the epoxy systems cured by commercial aromatic curing agents

Quantity and Quality of Vision Using Tinted Filters in Patients with Low Vision Due to Diabetic Retinopathy.

[en] PURPOSE: To investigate the effect of tinted filters on visual acuity (VA), contrast sensitivity and patient satisfaction in diabetic retinopathy associated with low vision. METHODS: In a prospective study, 51 patients with diabetic retinopathy and low vision were assessed. We chose a simple random sampling method and used the patient's files for data collection. LogMAR notations were applied for assessing VA and a contrast sensitivity chart (CSV-1000) was employed for measuring contrast sensitivity. First, measurements were performed without tinted filters and then using them. Appropriate lenses were given to the patients for 2 days, and they were questioned about their satisfaction using them in different places. RESULTS: A total of 20 male and 31 female patients with mean age of 57.3 years participated in the study. With a 527 ± 10 nm filter, mean VA improved significantly (P ≤ 0.05). Using the 527 ± 10 nm and 511 ± 10 nm filters, mean contrast sensitivity was improved significantly at 3 and 6 cycles/degree frequencies (P < 0.05). The effect of other filters on VA and contrast sensitivity was not significant. Patient satisfaction rate was generally high. CONCLUSION: Tinted filters are able to rehabilitate low-vision patients due to diabetic retinopathy. The 527 ± 10 and 511 ± 10 nm wavelength filters improved contrast sensitivity and the 527 ± 10 nm filter improved VA to some extent. Further investigations are recommended to assess the effect of these filters in patients with other causes of low-vision

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic