3D Simulation Of Jet-A Combustion In A Model Aircraft Engine Combustion Chamber.

The primary objective was to compare the emission data measured on CFM56-2C1 engine during APEX (Aircraft Particle Emission eXperiment) campaign by NASA. Four engine operating conditions, idle/taxi, approach, climb and take-off have been considered. NOx emission has been predicted in fair agreement with the APEX data. CO was highly over-predicted whereas CH and C2H2 were under-predicted. Several contours of different variables such as temperature, pressure, velocity, mass fraction of major species have been analyzed to understand the physics and chemistry inside the combustion chamber

Uniform algebras and distinguished varieties

In this article, we point out the connections between the distinguished varieties introduced by Agler and McCarthy with certain uniform algebras on bidisc studied by Samuelsson and Wold. We also prove analogues of Samuelsson-Wold result for the domains in $\mathbb{C}^2$ that are the images of the bidisc under certain proper polynomial map on $\mathbb{C}^2$. We also give a description of polynomial convex hull of graph of anti-holomorphic polynomial over the distinguished boundary of such domains. We mention the case for the symmetrized bidisc as an example

Microfinance and women empowerment in Bangladesh: Impact in economic, social and political dimensions.

This thesis empirically examines the impact of microfinance services on women’s economic, social and political empowerment in Bangladesh. Microfinance is alternative financial services for poor people, predominantly for women as they are more poverty-stricken and discriminated in Bangladesh. These services are more likely to be flexible than formal financial services so that poor women can afford and use for productive activities which can generate income either for them or for their families. Thus, women may create a chance to uplift themselves from current deprived conditions in many aspects include financial, familial, social and public life. Therefore, this thesis aims to assess whether microfinance contributes to women’s empowerment, specifically in economic, social and political dimensions. A sample of 316 women clients of two microfinance institutions, Grameen Bank and BRAC in Bangladesh were selected. 285 questionnaires were completed and returned by the respondents and that constituted the data for the study. Several data analysis methods were deployed to analyse the collected data. It has been found that women in Bangladesh are empowered economically to a certain extent by the microfinance services. Economic empowerment was measured through women’s household income, savings and control over finances. Regarding this dimension of empowerment, findings of this thesis suggests the relationship of the amount of loan with household income, savings and control over finances, nevertheless, there is no relationship found with women’s geographic areas (rural, semi-urban and urban). Women’s engagement with income-generating activities and their long-term membership escalate the probability of increasing household income. In terms of women’s savings, findings show that the larger the amount of loan, the more the probability of increasing their savings. Increase in household income and increase in women’s savings are added as independent variables to assess their impact in women’s control over finances. Findings show that women with increased household income and savings have more probabilities in increasing control over finances. Likewise, women’s engagement with income-generating activities intensify the probability of increasing control over finances. As far as age is concerned, middle aged women have more chance of increasing control comparatively. Secondly, it has been found that women in Bangladesh are not socially empowered by the financial services of microfinance institutions. Social empowerment was measured through women’s agency of decision-making and mobility. To assess the causal relationship, this research has deployed the amount of loan, increase in household income and women’s geographic areas as key independent variables. Other variables include women’s literacy and communication skills used as proxies of human and social capital. Findings of thesis suggest that both amount of loan and increase in household income are found insignificant. However, women’s area is found statistically significant for both agency of decision-making and mobility. Relationship is found between women’s literacy skills and agency of decision-making. Nonetheless, bizarrely, women’s engagement with income-generating activities have negative relationship with their mobility. Women’s agency of decision-making was used as an independent variable to assess the impact on mobility where a positive relationship is found between them. Finally, it has been found that women in Bangladesh are not politically empowered by the financial services of microfinance institutions. Political empowerment was measured through women’s community and political participation. Findings of this thesis suggest that neither the amount of loan nor the communication skills is found statistically significant. Women’s engagement with income-generating activities is found statistically significant, however, it shows the negative relationship. Nevertheless, women’s freedom of movement is found to have a relationship with political empowerment. The findings show that women who have disagreed in terms of increasing mobility after joining microfinance, they have lower probability to increase their political empowerment. This study acknowledges the importance of women’s access to financial resources to their economic development and empowerment. It also highlights the importance of non-financial achievement during their involvement with microfinance such as women’s human capital for their social empowerment. It infers that women’s access to financial resources are fundamental for their economic empowerment, however not for social and political empowerment. With respect to the policy implication, government’s policy may incorporate poor women to the public financial system so that they receive financial capital when they need. Women’s easy access to resources is fundamental to the economic development of the country as they constitute half of the country’s population. Microfinance institutions might consider amplifying the loan size. Following women’s access to finance, policy of microfinance institutions should include stringent monitoring system so that it is actually women who are in control of the loan and utilise it in productive ways. Microfinance institutions may consider initiating additional programmes such as intense literacy, education and business development training which might be conducive for women’s social empowerment. Also, inclusion of political education and leadership training would increase the political knowledge of women directly and inspire them to participate in political activities. Nevertheless, implementing these programmes will cost additional expenses, therefore, government and the donors may join the microfinance institutions to patronise these programmes for improved and resilient human resources of the country. To the researcher’s knowledge, in Bangladesh, this study is possibly the first in the literature of microfinance and empowerment which shows the impact of microfinance in multiple dimensions simultaneously. Empowerment studies were frequently studied in the context of economic dimension; however, social and political dimensions are often neglected. Only three studies, for instance, Hashemi et al., (1996) in Bangladesh, Deininger and Liu (2013) in India and Goldman and Little (2015) in Tanzania investigated the social and political dimensions to the researcher’s knowledge. Nevertheless, none of these studies did not assess the economic aspects such as impact on household income and savings through microfinance which are major indicators of economic empowerment. Secondly, this study investigates the impact of access to credit on three settings such as in rural, semi-urban and urban area to see whether there are any differences based on different locations. To the researcher’s knowledge, in Bangladesh, this is possibly the first study of microfinance and empowerment in multiple dimensions that considered this variable. Thirdly, empirical studies of microfinance and empowerment in Bangladesh have rarely been analysed using economic theory while it has the potentiality to generate useful insights. This study has the application of an economic theory, for instance, women empowerment is analysed using women’s fall-back or breakdown position in this study within cooperative bargaining model proposed by McElroy and Horney (1981). Lastly, findings of this study suggest that financial services of microfinance are conducive for economic empowerment, but not for social and political empowerment. Thus, this research contributes to the literature

Development of piezoelectric micro-energy harvesting system using voltage doubler

Nowadays renewable micro-energy harvesting system is becoming attractive, because this energy is free which leads to reduce energy cost. Piezoelectric is one of the common energy harvesting systems. Generally, the output of a piezoelectric transducer is a small AC voltage and its power is also small. As a result, the convertion of this low AC voltage into DC voltage by using rectifier diode is not suitable since a cut-in voltage drop redues the output voltage as well as power of the system. A micro-energy harvesting interface circuit has been developed by using voltage doubler to improve the performace. The design is a modified model of buck boost converter. In this technique, at first the input voltage is incresed by a voltage double then it is used into a buck boost converter. A diode and a single capacitor have been used in this design instead of bridge rectifier which overcomes the diode conduction losses. 3.4V DC accros a load 1kΩ is obtained when the output voltage of the piezoelectric transducer is 0.54V AC. The circuit has been simulated by using PSpice (V16.5) electronic circuit simulation software and maximum power dissipation 57mW is obtained at the load which is supposed to be better compared to other conventional designs

Parameter optimization for piezoelectric micro-energy harvesting system

A piezoelectric micro-energy harvesting system is composed of piezoelectric transducer, rectifier, DC to DC converter and storage device. Parameters of the DC to DC converter have been optimized to harvest maximum energy from piezoelectric transducer. The key parameters are switching frequency, duty cycle, output load and inductance have been studied. The input voltage of the circuit from the piezoelectric transducer of 0.3V AC amplitude and output DC load voltage of 1.91V are considered. The circuit has been simulated using PSpice (V16.5) electronic circuit simulation software. The results show that the efficiency of the energy harvesting circuit is 34% and the maximum output power across the load is 3.69mW

Chemistry of ruthenium with some phenolic ligands: synthesis, structure and redox properties

Reaction of three phenolate ligands, viz. salicylaldehyde (HL1), 2-hydroxyacetophenone (HL2) and 2-hydroxynaphthylaldehyde (HL3), (abbreviated in general as HL, where H stands for the phenolic proton) with [Ru(PPh3)3Cl2] in 1¦1 mole ratio gives complexes of the type[Ru(PPh3)2(L)Cl2]. The structure of the [Ru(PPh3)2(L2)Cl2] complex has been solved by X-ray crystallography. The coordination sphere around ruthenium isO2P2Cl2 with a cis-trans-cis geometry, respectively. The [Ru(PPh3)2(L)Cl2] complexes are one-electron paramagnetic (low-spin d5, S=½) and show rhombic ESR spectra in 1¦1 dichloromethane-toluene solution at 77 K. In dichloromethane solution the [Ru(PPh3)2(L)Cl2] complexes show several intense LMCT transitions in the visible region. Reaction between the phenolic ligands and [Ru(PPh3)3Cl2] in 2¦1 mole ratio in the presence of a base affords the [Ru(PPh3)2(L)2] complexes in two isomeric forms. 1H NMR spectra of one isomer shows that it does not have any C2 symmetry and has the cis-cis-cis disposition of the three sets of donor atoms. 1H NMR spectra of the other isomer shows that it has C2 symmetry. The structure of the isomer of the [Ru(PPh3)2(L1)2] complex has been solved by X-ray crystallography. The coordination sphere around ruthenium is O4P2 with a cis-trans-cis disposition of the carbonylic oxygens, phenolate oxygens and phosphorus atoms, respectively. The [Ru(PPh3)2(L)2] complexes are diamagnetic (low-spin d6, S=O) and show intense MLCT transitions in the visible region. Cyclic voltammetry on the [Ru(PPh3)2(L)Cl2] complexes shows a ruthenium(III)---ruthenium(II) reduction near -0.3 V versus SCE and a ruthenium(III)---ruthenium(IV) oxidation in the range 1.08-1.24 V versus SCE. Cyclic voltammetry on both isomers of the [Ru(PPh3)2(L)2] complexes shows a ruthenium(II)---ruthenium(III) oxidation within 0.09-0.41 V versus SCE, followed by a ruthenium(III)-ruthenium(IV) oxidation within 1.31-1.52 V versus SCE

Simulation and evaluation of a phase synchronous inverter for micro-grid system

The phase synchronous inverter is an electrical inverter device which is synchronizing inverter phase with the micro-grid phase. Generally, DC voltage supply is considered as the input of the DC to AC inverter which is a renewable energy source such as solar panel, wind turbine and battery storage, etc. The three phase three layer phase synchronous inverters are normally utilized in the high power transmission and distribution systems to supply AC voltage to the three phase micro-grid loads. It has a phase synchronous controller, which includes voltage controllers that contain current regulator and DC voltage regulator to get the reference output power for creating the inverter gate pulses. An inverter utilizing a three leg IGBT has been designed and simulated by using MATLAB2014a/Simulink with the Simscape/SimPower-Systems Block Set. The inverter is connected to an input DC source, an output filter and a controller circuit. It has been observed that the output phase of the inverter is synchronized with the micro-grid phas

Three phase three layer phase synchronous inverter for microgrid system

A three phase three layer phase synchronous inverter is used for its high efficiency and simple switching control in the power management system. Compared to conventional inverters its output-waveform has less higher harmonic distortion. The phase synchronous inverter is designed by using well-established theory and used in microgrid power systems. The switching logic control, phase synchronization, low pass filter and DC source coupling for the inverter have been described details in this paper. This study may be useful to the researchers for finding the relevant references especially in the fields of three phase three layer phase synchronous inverter

Wireless power transmission system based on magnetic inductive resonance of couple circuit

In this paper, a couple circuits are used to transfer power by magnetic inductive resonance or wireless inductive power transfer method where the individual nodes are batteryless to make them maintenance free. Magnetic inductive resonance mainly works on Electromagnetic field induced between two coils that are tuned to resonate at the same frequency. This type of method has a high Q(quality Factor) and Consist of air cored to avoid 'iron' losses. Wireless or batteryless sensors can be used for energy harvesting and energies are stored in capacitors. Microwave power transmission is a wireless power transmission scheme that can interfere with data transmission where magnetic inductive resonance suitable for data transmission and acquisition