SIMULATION OF ADAPTIVE CHANNEL EQUALIZATION FOR BPSK,QPSK AND 8-PSK SCHEMES

The distortion and inter symbol interference caused by multipath effects of channel degrades the quality of signal transmission in transmission system of digital baseband. Adaptive channel equalization is used commonly to compensate these effects so as to increase the reliability of propagation. Recursive Least Squares (RLS) algorithm is most commonly used adaptive algorithm because of its simplicity and fast convergence. In this work, simulation model of finite impulse response adaptive equalizer based on RLS is developed to reduce distortion caused by channel. The constellation diagram before and after equalization is obtained. It is observed that bit error rate is decreased by fifty percent after equalization. Hence this shows that the algorithm appears to reduce channel effects effectively and achieves channel equalization

Tamil-Llama: A New Tamil Language Model Based on Llama 2

Language modeling has witnessed remarkable advancements in recent years, with Large Language Models (LLMs) like ChatGPT setting unparalleled benchmarks in human-like text generation. However, a prevailing limitation is the underrepresentation of languages like Tamil in these cutting-edge models, leading to suboptimal performance in diverse linguistic contexts. This paper addresses this lacuna, enhancing the open-source LLaMA model with an addition of 16,000 Tamil tokens, aiming to achieve superior text generation and comprehension in the Tamil language. We strategically employ the LoRA methodology for efficient model training on a comprehensive Tamil corpus, ensuring computational feasibility and model robustness. Moreover, we introduce a Tamil-translated version of the Alpaca dataset and a subset of the OpenOrca dataset tailored for instruction fine-tuning. Our results showcase significant performance improvements in Tamil text generation, with potential implications for the broader landscape of LLMs in Indian languages. We further underscore our commitment to open research by making our models, datasets, and code publicly accessible, fostering further innovations in language modeling.Comment: 19 pages, 10 figure

SIMULATION OF A BACKREST MOMENT TEST FOR AN AUTOMOTIVE FRONT SEAT USING NONLINEAR CONTACT FINITE ELEMENT ANALYSIS

Computer aided engineering and finite element simulation are essential in order to predict accurately the safety performance of automotive structures in an event of crash. In this work, finite element simulation is used to evaluate the strength and deflection characteristics of a reference automotive front seat in an event of vehicle rear impact. Understanding the strength-deflection characteristics of front automotive seats during vehicle rear impact is important to ensure the safety function of the seat. The safety function is measured based on a moment test in accordance with government (ECE R17) regulations. Accurate finite element modeling of a reference seat which has passed ECE R17 moment test requirements is important to provide a benchmark reference to compare new concepts and designs which reduce weight while maintaining minimum test requirements. In this work, simulation of the moment test of the reference seat is done beyond the component level by using a complete seat model formed by integrating the major structural components including the base frame, slider rails and backrest. The stamped sheet metal structural frames are represented in the finite element using shell elements. Contact within the seat structure is defined in order to simulate joints between side flanges and cross tube members of the base frame. Contact modeling is also used to simulate the interaction of a SAE J826 rigid body form with the backrest. Height adjustment, front tilt adjustment and the backrest tilt angle adjustment locking mechanisms are represented in the finite element model using rigid connections. The bolt connections between different parts in the model are represented using multi-point constraints. An elastic-plastic material is used to model the ductile steel structures. Different grades of steel with low, medium, and high ultimate strength are considered for the different components. In order to confirm the strength requirements, moment deflection characteristics of the seat are studied in accordance with ECE R17. The strength and deflection characteristics of the seat are obtained by simulating the quasi-static moment test in ABAQUS/Explicit using two complementary loading cases, constant horizontal force and constant angular velocity. For the moment test, simulated using constant horizontal force, the results show that the seat satisfies a maximum moment requirement and, at the end of the deformation travel, the developed moment is maintained above a minimum requirement. For the moment test simulated using the constant angular velocity, the maximum moment is not reached, yet after the end of deformation travel, the developed moment stays above the minimum. Since the ECE R17 regulations do not provide precise specifications for the height of the applied force and test setup for the body form pivot mechanism, a study is conducted in order to understand the influence of body form rotation and height of the body form above the H-point, representing the physical pivot of the occupant hip area. The influence of plastic material properties of different grades of steel used for the seat model, front mesh contour on the backrest and connection between the backrest and connector are also modified to analyze the influence of load path on moment deflection characteristics of a seat. The moment test setup with increased distance of 430 mm between H-point and reference point of the body form shows higher strength for initial deflection and lower strength towards the end of the deformation path when compared to original length of 360mm. The moment test setup with body rotation about the reference point axis constrained shows higher strength for initial deflection and similar strength towards the end of the deformation path when compared to free rotation of the body form reference point axis. The front mesh without contour on the backrest decreases the strength of the seat below the requirement. Changing the ultimate strength of steel used on the major load bearing components does change the component stress, but shows only a small change in the moment deflection characteristics of the model. Using a high yield strength steel material for the connector increases the maximum moment that the seat can suppor

Quantification of short-term erosion rates using the cosmogenic radionuclide Be-7

ABSTRACT The fallout radionuclides 137Cs, 210Pbex are used widely for obtaining quantitative information on soil erosion and sediment redistribution rates within agricultural landscapes, over several spatial and temporal scales, and they are frequently seen to represent a valuable complement to conventional soil erosion measurement techniques. However, measurements of these radionuclides provide estimates of medium term (i.e. 40-100 years) soil erosion rates. The shorter-term perspective provided by the 7Be method has the potential to estimate soil erosion rates associated with individual events or short periods. The 7Be method has become increasingly relevant in an environment impacted by climate change, changing land use and other human activities. The present work establishes a mathematical model based on the physical processes of molecular diffusion and radioactive decay, to study the vertical behaviour of 7Be in soils. This model was further used to quantify erosion rates for 12 individual erosional events over a period of two years at our study site in Müncheberg, Germany. The scope of the model was explored analytically as well as numerically for Pulse-like fallout initial condition, zero concentration initial condition and exponential distribution initial condition. The model was fitted to more than 15 depth distributions and the resulting model parameter, effective diffusion coefficient D, is evaluated. In general diffusion coefficients estimated were of the order of 10-12 10-13 m2 s-1 for loamy to sandy soil types. Diffusion coefficients estimated for our study site were about 10-13 m2 s-1. The soil analyses indicate that the diffusion coefficient D is not merely a fitting parameter, but is related to the physico-chemical properties of radionuclide transport in soils. The erosion rates estimated at tilled and no-till plots at our study site were between < 0.001 - 4.7 ± 0.4 kg m-2 and 0.3 ± 0.5 kg m-2 - 2.0 ± 1.4 kg m-2 respectively. The magnitude of erosion rates estimated at the no-till plots was less than that at the tilled plots. The main conclusions of this work are: - The mathematical model developed during this study describes the transport of 7Be in soils. It is the first extensive model proposed so far that despite of its many simplifications, adequately represents the exponential distribution of 7Be profiles at disturbed and undisturbed or reference sites. - Main physical processes, which transport of 7Be in soil are, diffusion and radioactive decay. Migration parameters and measurements confirm that sorption is the main physical process, which confines 7Be concentration to soil surface. - Current erosion estimation methods with 7Be available in the literature for estimating erosion rates for single rainfall event was successfully modified to quantify erosion rates for multiple rainfall events. - Erosion rates estimated with 7Be technique were successfully used to differentiate between the rill-interrill, splash and surface erosion at the study plot. - The Diffusion model proposed in this study does not take into account the vegetation cover and thus overestimates the erosion rates or in some cases shows the occurrence of deposition on the plot

Side effects to antithrombotic therapy in patients with COVID-19 infection

Universitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu”, Chişinău, Republica MoldovaIntroduction. Severe Acute Coronary Syndrome (SARS) corona virus-2 as SARS-CoV-2, led to an outbreak of respiratory infections started from Wuhan, China. COVID-19 has been associated with inflammation and prothrombotic state. Due to the state of hypercoagulability in covid-19, use of antithrombotic therapy for preventing thrombotic complications occurred. Purpose of the study. The relative risk versus benefit of antithrombotic therapy have not been addressed with clear distinction as of till now. This study focuses on possible negative side of therapy in covid patients using existing literature and clinical study findings. Materials and Methods. This study was performed by analysis and breakdown of existing literature concerning the topics SARS-CoV-2, hypercoagulability and antithrombotic therapy using online search engines like Google Scholar, PubMed, Hinari etc. The pathological association studies and drugs for treatment of SARS-CoV-2 patients were also referred for the study. Results. Major negative effect of antithrombotic therapy was bleeding. Anticoagulants was associated with increased risk of bleeding and complications mostly in the-rapeutic dose. In critically ill patients, therapeutic dose did not improve outcome but increased risk of bleeding whereas in moderately ill patients result was contradictory. In the latter therapeutic-dose heparin or LMWHs increased survival in different randomized clinical trials but no difference in primary result in this category from other studies. Nirmatrelvir-ritonavir (Paxlovid) usage interacted with some medications. There was an increased risk of blood clots when Paxlovid had higher risk of blood clots with clopidogrel and bleeding with ticagrelor. It interacted with DOACs, simvastatin, lovastatin, and anti-arrhythmics. Dexamethasone and covid infection had effects on drug metabolism. Conclusions. Most important entities associated with negative effect of anti-thrombotic therapy in covid patients needed to be addressed were bleeding and drug interactions. Rather than a simple cause, multiple factors like drug regimen, dosage, concomitant medications, and individual patient factors play a role in development of side effects in covid patients

Blue light effect and ethnicity - in shadow of skin pigmentation and eye colour

Department of Human Physiology and Biophysics, Nicolae Testemitanu State University of Medicine and Pharmacy, Chisinau, Republic of Moldova, The 8th International Medical Congress for Students and Young Doctors, September 24-26, 2020Introduction. Blue light [wavelength between 400-495nm], from digital sources and artificial lighting in the evening, hence inhibit normal secretion patterns of melatonin causing circadian rhythm and sleep disturbances. There is an inversely proportional relationship between blue light exposure and melatonin secretion. In the same time, blue light can be absorbed by the pigmental layer of the retina that contains melanin. Thereby, the quantity of blue light that will rich the retina can be influenced by the amount of melanin from the eyes. Aim of the study. The purpose is to appreciate the circadian rhythm and sleep disturbances and depth of blue light effect on melatonin secretion on different ethnical groups, integrating skin and eye pigmentation effects on the same matter; Materials and methods. An analysis of the latest scientific sources has been carried out using the PubMed search engines, 'HINARI' and Google Academic with the help of keywords: blue light, ethnicity, skin pigmentation and eye colour, sleep quality, sleep consistency, sleep duration. Results. The role of ethnicity in most aspects of human health is well documented. An example is the inefficiency of certain drugs used in asthma treatment in certain racial groups. Other studies determined a decrease in prevalence and incidence of Parkinson Disease in Americans of African descent compared to Caucasians. Also, shorter sleep was reported in black than in Asian, in Asian than in Hispanic/Latin and in Hispanic/Latin than in White. More sleep quality disturbance was reported in Black than in Asian and in Asian than in Latin. One of the explanations of the influence of ethnicity on sleep is the amount of melanin in the eyes. Some studies have shown that physiological responses to light depend on eye colour and that intraocular light scattering is higher in blue-eyed Caucasians. The percentage of suppression of melatonin secretion two hours after the start of light exposure was significantly more abundant in light-eyed Caucasians than in dark-eyed Asians. In the same time, in a comparative study which analysed the influence of light treatment in Seasonal Affective Disorder (SAD), was found that following six weeks of light therapy, African-American participants with SAD had a lower remission rate than Caucasian participants. Researchers suggested that higher melanin content of the pupil and retinal pigment epithelium in African-Americans may reduce the retinal illuminance in African-American SAD patients during light treatment hence reducing the effect of light therapy. These results suggest that the sensitivity of melatonin to light suppression is influenced by eye pigmentation and can be related to ethnicity, respectively

Role of Low Lying Pubic Tubercle in the Development of Inguinal Hernia: A Case Control study

BACKGROUND: Abdominal wall is the site of opposing physical forces that may eventually result in the appearance of the hernias. The external abdominal hernias are the most common forms, the inguinal hernia being the commonly encountered type [75% of the abdominal hernia]. Many factors are responsible for the formation of the inguinal hernia but, what makes a few people more susceptible to this situation is still clearly not proved. Few of the previous studies have concluded that the low lying pubic tubercle is associated with the development of the inguinal hernia. OBJECTIVES: This study was designed to investigate the distance between the anterior superior iliac spines and the perpendicular distance of the pubic tubercle from the interspinal line MATERIALS & METHODS: 150 patients admitted in MGM general hospital which is attached to KAPV government medical college is taken as cases and control is choosen from opd patient who are not suffering from inguinal hernia with similar age, sex, weight and height. RESULTS: This study revealed that both parameters (interspinal SS distance and the pubic tubercle height ST) in the study group were significantly greater than that in the control group. The distance from mid inguinal point to the superficial inguinal ring was also measured in both the study and control groups and the results show that the distance is shorter in the individuals with the inguinal hernia.Identification of the structural characteristics of inguinal region enables the surgeon to perform the surgical technique appropriately. CONCLUSION: The low pubic tubercle group of cases have more tendency for herniation. The unusual origin of internal oblique muscle in cases with low lying tubercle is far away, from the external half of the inguinal ligament, leaving the internal ring unprotect ted during abdominal muscle contraction, which is another causation of hernia development

Characterization of high efficiency pseudo bilayer organic solar cells and identification of trap-states with a modified CELIV technique

Master'sMASTER OF ENGINEERIN

Arterial hypertension and COVID-19 infection new insights

Universitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu”, Chişinău, Republica MoldovaIntroduction. The SARS-Covid 2 infection was first reported in Wuhan, Hubei Province, China on 31 December 2019. Symptomatic SARS-CoV-2 infection was most frequent in the elderly and led to a more severe illness. At the same time, a large fraction of this patient population also suffered from arterial hypertension (AHT). Hence, AHT became a hot topic in the SARS-CoV-2 pandemic studies. Purpose of the study. This study aims to shine light on the current insights in this relationship spectrum. Materials and Methods. A literature analysis of the latest scientific sources has been carried out using the PubMed search engines, „HINARI” and Google Academic with the help of respective keywords. Additionally, a pathophysiological breakdown and newer advancements in this domain have been referred for the benefit of the study Results. AHT was the most prevalent cardiovascular comorbidity in patients with SARS-CoV-2 infection and a major risk factor for increased severity, mortality, and hospitalization. Influential factors included cardiovascular morbidity, co-morbidities, presenting symptoms, age of the patient etc. The role of AHT is mediated through its effect on the regulation of RAAS, inflammation, immunity and the gastrointestinal tract which partly explains the worse outcomes in covid patients. In contrast to the effect of AHT on SARS-CoV-2 patients, new- onset hypertension was also reported in a few post covid patients. RAAS inhibitors did not fuel clinical adversities and was associated with a lower risk of hospitalization, intubation and death. Newer therapies emerging from the common background include hACE2 and sACE2. Conclusions. AHT is an independent risk factor and the most frequently encountered co-morbidity in SARS-CoV-2 patients. New-onset AHT in post-covid patients points to a bidirectional relationship. Current data failed to discredit RAAS inhibitors. Newer therapies from common pathological background may help eliminate a vicious cycle from SARS-CoV-2 infection in AHT patients