N.M.R. studies of aromatic heterocyclic compounds

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Fabrication of CMUTS based on PMMA adhesive wafer bonding

Capacitive Micromachined Ultrasonic Transducers (CMUTs) are the potential alternatives for the conventional piezoelectric ultrasonic transducers. CMUTs have been under an extensive research and development since their first development in the mid- 1990s. Initially developed for air-coupled applications, CMUTs have shown far better acceptability in immersion-based applications (i.e. medical ultrasonic imaging, medical therapy, and underwater imaging) when compared to the piezoelectric ultrasonic transducers. CMUTs are parallel-plate capacitors fabricated using the Micro Electro Mechanical Systems (MEMS) technology. Despite of the fact that various CMUT fabrication methods have been reported in the literature, there are still many challenges to address in CMUTs design and fabrication. Standard fabrication techniques are further sub-divided into the Sacrificial Layer Release Process and the Wafer Bonding methods. A number of complications are associated with these techniques, such as optimization of the design parameters, process complexity, sacrificial layer material with the corresponding etchant selection, wafer cost and selection. In particular, the sacrificial release methods consist of complex fabrication steps. Furthermore, structural parameters like gap height and radius have optimization issues during the sacrificial release process. On the other hand, the wafer bonding techniques for the CMUTs fabrication are simple and have a great control over the structure parameters in contrast to the sacrificial release methods. At the same time, the wafer-bonded CMUTs require very high quality wafer surface and have a very high contamination sensitivity. For this purpose, this dissertation aims to develop a simple, low cost and lower constraint thermocompression-based technique for the CMUT fabrication. The proposed wafer bonding technique for the CMUT fabrication in the dissertation uses Polymethyl methacrylate (PMMA) adhesive as an intermediate layer for the thermocompression wafer bonding. The advantages associated with the PMMA adhesivebased wafer bonding over the other wafer bonding methods include low process temperature (usually 200 C or less), high wafer surface defects and contamination tolerance, high surface energy and low bonding stresses. These factors will add cost effectiveness and simplicity to the CMUTs fabrication process. Furthermore, the achieved receive sensitivity with the reported CMUT is found comparable to the commercially available ultrasonic transducer

An Overview of Droplet Impact Erosion, Related Theory and Protection Measures in Steam Turbines

Erosion of last-stage steam turbine blades is a well-known problem in the turbine manufacturing industry. Damage of structure and loss of efficiency are the common problems associated with erosion. Understanding of the phenomenon leading to low-pressure blade erosion, erosion protection and erosion prediction has been the topic of scientific research and interest in the steam turbine manufacturing community since the start of the nineteenth century. Although several changes in both the steam turbine stage design and steam properties have been adopted to eliminate this problem, none of them have proved to eradicate this phenomenon completely. The only option left for the scientists and designers is to mitigate the process by utilising materials with high erosion resistance. This requires the development of high erosion-resistive materials and then quantitative confirmation of their erosion resistance by using some precise and accurate laboratory methods reflecting the conditions in the last stage of steam turbines. An overview of droplet impact erosion and related theory has been addressed in this chapter. Moreover, different methods to quantify erosion on a laboratory scale will be presented. In addition, different measures to mitigate erosion in low-pressure stages of steam turbines will be described. In the end, different droplet impact erosion prediction approaches will be discussed

Periodic pp-adic Gibbs measures of qq-states Potts model on Cayley tree: The chaos implies the vastness of pp-adic Gibbs measures

We study the set of $p$-adic Gibbs measures of the $q$-states Potts model on the Cayley tree of order three. We prove the vastness of the periodic $p$-adic Gibbs measures for such model by showing the chaotic behavior of the correspondence Potts--Bethe mapping over $\mathbb{Q}\_p$ for $p\equiv 1 \ (\rm{mod} \ 3)$. In fact, for$0 < |\theta-1|\_p < |q|\_p^2 < 1$, there exists a subsystem that isometrically conjugate to the full shift on three symbols. Meanwhile, for$0 < |q|\_p^2 \leq |\theta-1|\_p < |q|\_p < 1$, there exists a subsystem that isometrically conjugate to a subshift of finite type on$r$symbols where$r \geq 4$. However, these subshifts on$r$symbols are all topologically conjugate to the full shift on three symbols. The$p$-adic Gibbs measures of the same model for the cases$p=2,3$and the corresponding Potts--Bethe mapping are also discussed.Furthermore, for$0 < |\theta-1|\_p < |q|\_p < 1,$we remark that the Potts--Bethe mapping is not chaotic when$p=2,\ p=3$and$p\equiv 2 \ (\rm{mod} \ 3)$and we could not conclude the vastness of the periodic$p$-adic Gibbs measures. In a forthcoming paper with the same title, we will treat the case$0 < |q|\_p \leq |\theta-1|\_p < 1$for all$p$

REMEDIAL AND PHYTOCHEMICAL REVIEW STUDY ON TECOMA STANSL.

Tecoma stans is a destructive invader that outcompetes natural florain its surroundings. This plant is considered as a modifier species which leads to a decrease in the biodiversity as well as natural resources. It has been planted as an ornamental garden and street plant, but possesses wide range of therapeutic and pharmaceutical applications. All parts (leaves, root, flower, seed, fruit, and bark) of the plant areusedas a remedy for different diseases. As anherbal remedythe plant parts are used for the treatment of diabetes, digestive problems, control of yeast infections, as powerful diuretic, vermifuge, anti-syphilitic, stomach pains and tonic. Preliminary phytochemical screening and isolation of compounds from this plant has revealed the presence of tannins, flavonoids, phenols, anthraquinones, glycosides, alkaloids, quinones and traces of saponins and amino acids. This article summarizesthe data on its medicinal applications and traditional uses

Depression and Anxiety, associated factors and the impact of workplace violence on psychologi-cal disorders among Korean Workers

Background: We have evaluated depression and anxiety and associated factors with these psychological stressful events for which almost all people around the world are prone to develop at some time period of life, each one of these two psychological prob-lems (depression and anxiety) have two different sources the first source of establishing that could be either as individuals’ own health condition or could be due working place. Purpose: The goal of this study is to understand key associated factors of depression and anxiety among Korean workers nationwide and to study whether worker’s exposure to physical violence and sexual harassment during last twelve month of the survey have correlations with workers’ depression and anxiety. Method: Data for this thesis was from fifth Korean Working Condition Survey which had been conducted in 2017. The population of the entire survey was 50,205 persons who had taken part in the survey. Relevant variables were chosen, Modification of data into subgroups was made to the variable of age of the participants. Data was analyzed with chi-square, Pearson correlation tests, and logistic regression. Data was analyzed with SPSS 26. As either anxiety or depression have many associated factors but in this study only those variables have been chosen which were statistically significant. Results: Workers who had been working older age, female gender, full time jobs and clients visit at the workplace are important factors known to have been associated factors with depression and anxiety due to workplace as well as in Korea. Conclusion: we suggest that all employers and private sectors should take care of their employees’ psychological burden, depression and anxiety bylaw.open석

SAMBUCUS NIGRA LINN: IN VIVO STUDIES ON RABBITS

Objective: The research work was carried out to explore the safety and efficacy of a low dose of Sambucus nigra Linn [S. nigra] extract on hematological, biochemical and histopathological parameters of rabbits organs (kidney, liver, stomach and heart). Methods: Sambucus nigra extract was given orally for 90 d to test group rabbits [Test female (SF); Test male (SM)]. Then blood samples of control [C (female); C (male)] and test rabbits were collected by cardiac puncture and changes in hematological, biochemical and histopathological parameters were observed and interpreted. Results: Gender-based differences were observed in hematological, kidney function, liver function, cardiac enzymes and lipid profile investigations. Urine analysis showed similar results as that of standard and control drug. No noteworthy pathology was observed in heart, stomach, liver and kidney tissues of rabbits, treated with Sambucus nigra in a dose of 25 mg/kg/day. Conclusion: Our results justify the well-documented safe and effective use of Sambucus nigra in medicine for curing various pathologies.Keywords: Black Elder, Anthocyanins, Anti-oxidant, Anti-viral, Europ

Composición de la materia orgánica de sedimentos intertrapeanos ricos en iridio de Anjar: Volcanismo en el Deccan e implicaciones paleoambientales durante el límite Cretático / Terciario

Se han aislado varias fracciones de compuestos orgánicos solubles a partir de sedimentos ricos en iridio. Se ha usado una combinación de técnicas de extracción con diferentes proporciones de benceno, cloroformo y metanol con éter de petróleo. Los análisis muestran la presencia de &#945;, &#946; - ésteres insaturados (C=C-COO-) y grupos alifáticos alquilo de larga cadena (-C-C-C-C-) en los sedimentos del límite Cretácico/Terciario (K/T) ricos en iridio. Los dos picos protónicos a &#948; 7,20 y 7,23 ppm del espectro 1H NMR, indican que las moléculas pueden ser glicéridos con grupos alifáticos alquilo de larga cadena. Igualmente, los picos en la región de &#948; 3,90-4,32 ppm muestran la presencia de un doble enlace (-C=C-) asociado a un grupo éster. Los picos encontrados en la región de 7,5-7,7 ppm mostraron la presencia de hidrocarburos aromáticos. El pico a &#948; 128 y 130 ppm del espectro 13C NMR también apoya la presencia del doble enlace antes mencionado. Se han asignado dos picos, a &#948; 68 y 70 ppm, a dos grupos alquílicos asociados a un grupo éster (-CH2-CH2-OOC-). El espectro de geopolímeros ocluidos en las arcillas, del lecho rico en iridio, es comparable a la lignina con desplazamientos químicos de C aromático (160 a 110 ppm), O alquílico C (100 a 60 ppm) y C alquílico (45 a 0 ppm). El espectro 13C NMR en estado sólido de la lignina revela un modelo comparable a los obtenidos en los estudios de la madera de angiospermas. Estos compuestos orgánicos alifáticos de larga cadena derivaron de moléculas orgánicas complejas y se formaron por un incremento brusco de la temperatura, pero en condiciones de baja presión. Es posible que los flúidos hidrotermales asociados al volcanismo del Deccan fueran el foco de calor contemporáneo de esas transformaciones. Estas observaciones vienen avaladas por la presencia de sepiolita-palygorskita-esmectita en la secuencia volcanosedimentaria de Anjar, que indica una alta basicidad en condiciones áridas inducidas e influenciadas por el volcanismo del Deccan