Effects of parameters of Helmholtz resonator on transmission loss of hybrid muffler

Expansion chamber and Helmholtz resonators are widely used in noise control. In this paper, they are combined to use as a hybrid muffler. The analysis is done to investigate the influence of the parameters of Helmholtz resonator on transmission loss. The transfer matrix method is used in the analysis. The result of transmission loss from the transfer matrix method is validated with the result from experimental two-load method using four microphones impedance tube. After had the transmission loss of the hybrid muffler been validated, the study was proceeded to investigate the effects of parameters of Helmholtz resonator on the transmission loss. The root mean square value of transmission loss were also calculated to compare the transmission losses clearly. In this paper, we investigated the effect of length of the neck of Helmholtz resonator, the effect of diameter of the neck of Helmholtz resonator, the effect of the length of the Helmholtz resonator cavity and the effect of the diameter of the Helmholtz resonator cavity for stationary medium. It is found that the transmission loss is increased when the diameter of the neck of Helmholtz resonator is increased. When the length of the neck is reduced, the transmission loss is increased. The transmission loss can also be increased by reducing the diameter of resonator cavity. It is better to increase the transmission loss at low frequencies by increasing the length of the resonator cavity

Stability analysis of a tall building with mat foundation over sandy soil with soil-structure interaction approach

This paper presents the stability analysis of a tall building with mat foundation founded on liquefaction susceptible soil during design earthquake. The stability of a structural foundation and structure itself is mainly depends on the bearing capacity of underlying soil during and after earthquake. Since modulus of subgrade reaction or stiffness of the soil is a conceptual relation between the soil pressure and deflection, it can be changed with fluctuation of net allowable bearing capacity of underlying soil. Bearing capacity of the soil can also be changed according with the value of liquefaction potential. The loss of spring stiffness occurred more or less depending on degree of liquefactions. Modification of localized spring stiffness of the foundation is carried out by numerical method. For a typical 2 unit 10 storey building, the stress states were chosen at a depth of 12 ft. It belongs to seismic zone 2A. ETABS software is used as a design aid for performance of numerical completion for the analysis of model. The focus of this paper is to study the influence of liquefaction potential on modifying spring stiffness of the soil under the building and potential failure modes of the building to be considered in soil structure interaction

Noise source identification of vacuum cleaner using sound pressure-velocity (PU) probe

Noise is unwanted sound that is loud or unpleasant or that causes disturbance. It is well known that the noise produced by vacuum cleaner is very loud and it is a common problem which needs to be address since it can disrupt individual’s comfortable hearing and concentration and while carrying out daily activities. In this paper, a series of measurement techniques was applied to diagnose the location of noise source. Sound Pressure Level and Sound Pressure- Velocity (PU) Probe equipment are used in the experiment to diagnose the location of noise source at the back, front, left, and right view of the vacuum cleaner.The technique is more efficient, making the noise identification process easier to facilitate the elimination of noise since it is easier to diagnose and locate the source of noise of vacuum cleaner. The 1/3 octave band data of the back, front, left, and right side view of vacuum cleaner are computed. Thenintensity measurement is presented in the form of noise mapping for each view. Based on the experimental results, the frequency and the dominant noise source of each view is identified

Asymptomatic and sub-microscopic malaria infection in Kayah State, eastern Myanmar

Myanmar has the heaviest burden of malaria in the Greater Mekong Sub-region. Asymptomatic Plasmodium spp. infections are common in this region and may represent an important reservoir of transmission that must be targeted for malaria elimination.; A mass blood survey was conducted among 485 individuals from six villages in Kayah State, an area of endemic but low transmission malaria in eastern Myanmar. Malaria infection was screened by rapid diagnostic test (RDT), light microscopy and real-time polymerase chain reaction (PCR), and its association with demographic factors was explored.; The prevalence of asymptomatic Plasmodium spp. infection was 2.3% (11/485) by real-time PCR. Plasmodium vivax accounted for 72.7% (8/11) and Plasmodium falciparum for 27.3% (3/11) of infections. Men were at greater risk of infection by Plasmodium spp. than women. Individuals who worked as farmers or wood and bamboo cutters had an increased risk of infection.; A combination of RDT, light microscopy and PCR diagnostics were used to identify asymptomatic malaria infection, providing additional information on asymptomatic cases in addition to the routine statistics on symptomatic cases, so as to determine the true burden of disease in the area. Such information and risk factors can improve malaria risk stratification and guide decision-makers towards better design and delivery of targeted interventions in small villages, representative of Kayah State

Fuzzy Control System for Aircraft Speed on Approaching Runway

A fuzzy decision system for air helping air-trafficexperts in controlling aircraft velocities and in keeping anaircraft flight within several constraints established of air lanesection. Automatic systems for air-traffic control are essentialdue to the ever increasing number of aircrafts flying all over theworld, the amount of environmental and aircraft constraints andthe necessary to guarantee the safety both for flights and for airtraffic operators. The proposed systems implement with fuzzycontrol system, to obtain the desired speed. The knowledge andrules are obtained from F7 pilots expects. In this system, we willmaintain the aircraft speed within the desired speed accordingto the knowledge and the rule

Genomic Tracking of SARS-CoV-2 Variants in Myanmar

In December 2019, the COVID-19 disease started in Wuhan, China. The WHO declared a pandemic on 12 March 2020, and the disease started in Myanmar on 23 March 2020. In December 2020, different variants were brought worldwide, threatening global health. To counter those threats, Myanmar started the COVID-19 variant surveillance program in late 2020. Whole genome sequencing was done six times between January 2021 and March 2022. Among them, 83 samples with a PCR threshold cycle of less than 25 were chosen. Then, we used MiSeq FGx for sequencing and Illumina DRAGEN COVIDSeq pipeline, command line interface, GISAID, and MEGA version 7 for data analysis. In January 2021, no variant was detected. The second run, during the rise of cases in June 2021, showed Alpha, Delta, and Kappa variants. The third and the fourth runs in August and December showed only a Delta variant. Omicron and Delta variants were detected during the fifth run in January 2022. The sixth run in March 2022 showed only Omicron BA.2. Amino acid mutation at the receptor binding domain of Spike glycoprotein started since the second run coupling with high transmission, recurrence, and vaccine escape. We also found the mutation at the primer targets used in current RT-PCR platforms, but there was no mutation at the existing antiviral drug targets. The occurrence of multiple variants and mutations claimed vigilance at ports of entry and preparedness for effective control measures. Genomic surveillance with the observation of evolutionary data is required to predict imminent threats of the current disease and diagnose emerging infectious diseases

<b>ERICC Working Paper_ERICC Research Agenda for Cox’s Bazar, Bangladesh</b>

Cox’s Bazar in Bangladesh remains one of the world’s most difficult places for education delivery in conflict and protracted crises, as Rohingya communities who fled state violence in Myanmar face multiple barriers to education access, quality, and continuity under a coherent system. Despite this situation, there is a critical lack of systematic evidence on the development, implementation, and impact of education interventions among host and Rohingya communities. Informed by the ERICC Conceptual Framework and consultations with local stakeholders, our research agenda tackles the problem by developing a series of studies on three key aspects of education in Cox’s Bazar: ongoing responses to the recently introduced Myanmar curriculum, the current role of madrasas and their potential as partners for education interventions, and an analysis on continuing education for girls and older adolescents. These studies will collect novel data on little-understood areas of education in host and refugee communities, fill knowledge gaps at policy system and local system levels, and provide much-needed insights to inform policy and research on education under conflict and protracted crises in Cox’s Bazar and beyond.</p