Control Analysis of Stand-Alone Wind Power Supply System with Three Phase PWM Voltage Source Inverter and Boost Converter

Wind power supply system is an effective, environmentally friendly power source for household and other applications. According to the wind speed changes in variation the output power of wind generator is not stable and constant. This paper proposes the variable speed stand-alone wind power supply system that includes Permanent Magnet Synchronous Generator, three phase diode rectifier, DC-DC boost converter, battery energy storage system, and voltage source inverter. DC-DC boost converter controls to extract maximum power from the available wind power. Battery energy storage system through bidirectional converter is to supply the load when wind power is shortage. To get the desired output voltage and frequency at the load side, the voltage source inverter with the sinusoidal pulse width modulation (SPWM) control technique has chosen. The harmonics generated from the VSI are filtered with simple passive LC filters.  Simulation results of output voltages and currents, the total harmonic distortion (THD) are presented using MATLAB/Simulink

Artisanal-small Scale Mining in Myanmar

In many parts of the world, artisanal or small-scale mining activities are at least as important as large-scale mining activities. The numbers of people employed are actually considerably greater than in large companies. In 2002, an estimated 13 million people a large percentage of those are women and children are artisanal and small scale miners operating mainly in developing countries. Although the numbers of small-scale miners and their dependents are estimated at up to 80-100 million people, governments are frequently reluctant to give legal recognition to artisanal miners. This paper discusses approaches to develop the Artisanal–Small Scale Mining (ASM) sector in developing countries. This includes choice of mineral commodity, available technologies and economic/geological criteria. Other considerations include access to finance, area selection, and personnel. The parameters of mineral eco­nomic analysis are also essential for a successful ASM mining operation. Finally, choice of mining equipment is critical to success

A peptide inhibitor of exportin1 blocks shuttling of the adenoviral E1B 55 kDa protein but not export of viral late mRNAs

AbstractThe human subgroup C adenoviral E1B 55 kDa and E4 Orf6 proteins are required for efficient nuclear export of viral late mRNAs, but the cellular pathway that mediates such export has not been identified. As a first step to develop a general approach to address this issue, we have assessed the utility of cell-permeable peptide inhibitors of cellular export receptors. As both E1B and E4 proteins have been reported to contain a leucine-rich nuclear export signal (NES), we synthesized a cell-permeable peptide containing such an NES. This peptide induced substantial inhibition of export of the E1B protein, whereas a control, non-functional peptide did not. However, under the same conditions, the NES peptide had no effect on export of viral late mRNAs. These observations establish that viral late mRNAs are not exported by exportin1, as well as the value of peptide inhibitors in investigation of mRNA export regulation in adenovirus-infected cells

Travel Behaviour and Perceptions of Malaysian Airline Passengers during Endemic COVID-19

The study examines Malaysian airline passengers' travel behaviour and perceptions during the endemic Covid-19 after Malaysia re-opened the border. People are free to do an activity, especially travelling by aeroplane. Data were collected through an online platform in 2023. 390 data were obtained and used for the analysis. Findings reveal that 86.15% of Malaysian have travelled by aeroplane since the endemic, and 14.10% have travelled more than five times. 54.44% strongly agree they will avoid travelling with aircraft because of a few personal issues. In addition, results revealed a significant change in passengers' behaviour and perception when travelling after the hit of Covid-19 worldwide

Identification of RecQL1 as a Holliday junction processing enzyme in human cell lines

Homologous recombination provides an effective way to repair DNA double-strand breaks (DSBs) and is required for genetic recombination. During the process of homologous recombination, a heteroduplex DNA structure, or a ‘Holliday junction’ (HJ), is formed. The movement, or branch migration, of this junction is necessary for recombination to proceed correctly. In prokaryotes, the RecQ protein or the RuvA/RuvB protein complex can promote ATP-dependent branch migration of Holliday junctions. Much less is known about the processing of Holliday junctions in eukaryotes. Here, we identify RecQL1 as a predominant ATP-dependent, HJ branch migrator present in human nuclear extracts. A reduction in the level of RecQL1 induced by RNA interference in HeLa cells leads to an increase in sister chromatid exchange. We propose that RecQL1 is involved in the processing of Holliday junctions in human cells

Power Conversion Model and Simulation of Grid Connected Solar and Wind Hybrid System

This paper deals with system model, power conversion process, and conversion control of grid connected solar-wind hybrid system. The contribution of the installed PV capacity is 80 kW, and 30 kW of wind turbine which are connected in parallel to a common DC-link bus. As the three levels three stages of voltage source grid inverter is connected   to this DC-link bus, the stable bus voltage i.e. 600 VDC is maintained by controlling both of the DC-DC boost converters to the PV side and to the permanent synchronous wind turbine side via a rectifier. The power integration to the utility grid of 11 kV line is performed by the grid inverter through a three phase step-up transformer rated with 400 V/ 11kV, 120 kVA. The power conversion process is taken by considering the variation of solar radiations, PV cell temperatures, and wind speeds. By the help of the power conversion control, the total generated electrical power from the hybrid system can be injected to the utility grid line. In this paper, each of the proposed hybrid system components are developed in MATLAB/Simulink model for observing the feasibility of the available injected power to the grid line under the nature variations of the input power sources. The maximum power point tracking method is approached for getting effectiveness of the available maximum utilization power from the hybrid sources. The control technique of sinusoidal pulse width modulation is applied for generating control pulses of the controllers used in power conversion process. The grid synchronization is performed by the grid inverter control with phase lock loop with grid voltage. This paper mentions and makes discussion briefly about the observations from the simulating results of the proposed overall power conversion model

Monetary Policy and Exchange Market Pressure in Malaysia

Exchange market pressure (EMP), which provides a measure of the volume of intervention necessary to achieve any desired exchange rate target, is the latest model used in measurement of exchange rate condition. In order to obtain a more complete picture of Malaysia’s condition and to examine how Bank Negara handles different exchange market pressures, this study considers the Malaysian exchange rate in relation to that of its two major trading partners– namely, Japan (RM/YEN exchange rate) and the United States (RM/USD exchange rate)– to construct EMP models. Monthly data from 1990:1 to 2008:9 were used in this study, and the sample period has been divided into a few periods based on crisis periods and Malaysia’s experience in different exchange rate regimes. Vector autoregression (VAR) modeling is used. The study’s findings suggest that the prescription of traditional theory was not followed by Malaysia and that Bank Negara should implements different monetary policy with different EMP only under crisis and fixed exchange rate regimes

Feasibility and limitations of acridine orange fluorescence technique using a Malaria Diagnosis Microscope in Myanmar.

We studied parasite detectability in thick films by an acridine orange fluorescence technique (AO) to test its applicability and the use of a Malaria Diagnosis Microscope (MDM)-ESL in the detection of parasites, compared to the conventional Giemsa staining method. This study was conducted on 1,390 clinically suspected malaria cases of Thaton township, Myanmar. We found sensitivities of 82.8% for Plasmodium falciparum (P. falciparum) and 100% for Plasmodium vivax (P. vivax) and specificities of 97.1% for P. falciparum and 98.6% for P. vivax. AO had a higher sensitivity than Giemsa-stained films at low levels of parasitemia (&#60; 1,000/microl). AO showed lower sensitivity and higher specificity than the Giemsa method at parasite levels of more than 1,000/microl. The results of using the AO method, achieved by both novice and experienced observers, showed no significant difference and required less practice to perform the test as well as to identify the parasite. The acridine orange fluorescence technique using a malaria diagnosis microscope MDM-ESL series is simple, rapid and cost effective. The microscope is conveniently operable using standard AC power or a 12-V DC car battery, and it is easily convertible to a conventional biological microscope. With the exception of species differentiation, which is not possible with this method, this method would be appropriate for both clinical and epidemiological studies.</p

An oligotrophic deep-subsurface community dependent on syntrophy is dominated by sulfur-driven autotrophic denitrifiers

Subsurface lithoautotrophic microbial ecosystems (SLiMEs) under oligotrophic conditions are typically supported by H₂. Methanogens and sulfate reducers, and the respective energy processes, are thought to be the dominant players and have been the research foci. Recent investigations showed that, in some deep, fluid-filled fractures in the Witwatersrand Basin, South Africa, methanogens contribute <5% of the total DNA and appear to produce sufficient CH₄ to support the rest of the diverse community. This paradoxical situation reflects our lack of knowledge about the in situ metabolic diversity and the overall ecological trophic structure of SLiMEs. Here, we show the active metabolic processes and interactions in one of these communities by combining metatranscriptomic assemblies, metaproteomic and stable isotopic data, and thermodynamic modeling. Dominating the active community are four autotrophic β-proteobacterial genera that are capable of oxidizing sulfur by denitrification, a process that was previously unnoticed in the deep subsurface. They co-occur with sulfate reducers, anaerobic methane oxidizers, and methanogens, which each comprise <5% of the total community. Syntrophic interactions between these microbial groups remove thermodynamic bottlenecks and enable diverse metabolic reactions to occur under the oligotrophic conditions that dominate in the subsurface. The dominance of sulfur oxidizers is explained by the availability of electron donors and acceptors to these microorganisms and the ability of sulfur-oxidizing denitrifiers to gain energy through concomitant S and H₂ oxidation. We demonstrate that SLiMEs support taxonomically and metabolically diverse microorganisms, which, through developing syntrophic partnerships, overcome thermodynamic barriers imposed by the environmental conditions in the deep subsurface