Split air-conditioner noise source identification through sound intensity mapping

As the global warming takes place in years, the electrical appliances such as air-conditioner have been installed in most residential, industrial, or even in the education institution to provide better air quality and ultimately reduces the heat transfer in the ambient. Common use of split air-conditioner system to give maximum capacity in a space is responsible to the accumulated noise generated by the outdoor unit of the system. Therefore, an experimental study has been done to identify the noise rating and location of the highest noise level emitted by the system through different temperature and fan speed. The sound intensity mapping together with the sound power level will be applied to ensure the reliability of the data for the study purposes. Generally, the results indicated that the noise were concentrated at the compressor and fan blades whereas the level were observed to be higher with the lower temperature and higher fan speed operated. The highest noise level also reported as high as 99.08 dB(A) which located at the compressor. Hence it can be concluded that mitigation action is needed since considerable noise are generated by the application of air-conditioner particularly at the compressor and condenser fan

Noise emission analysis in diesel engine with the palm oil methyl ester as a substitution fuel

Despite of the emergence of the hybrid and electric vehicle in the automotive sector recently, the power that constantly delivered by the petroleum-based engine still be the one of the important factors that was considered by the customer. Even so, the automotive manufacturers in the 20s are making a big move by producing the engine that possessed the ability to use the biodiesel up to 20 % of blending ratio since the biodiesel addition does not owe to much drop of engine performance. As the noise emission highly contribute to the environmental pollution apart from the poisonous gases released by the fossil fuel usage, this study was carried out to identify the effectiveness of biodiesel in reducing the noise generated by the engine using multiple blend ratio. The Sound Power Level (SPL) method was used to investigate the maximum noise produced together with the location of the noise generated by the engine when using different blend ratio. Various engine speed and load were used in order to give the most similar condition to the real-working engine. Generally, the results indicated that the changes of engine speed and load could owing to the gradually increment of noise level in the engine, nevertheless, the increment was reported to be partially for some of the setup with the Pure Diesel (D100) usage. With the biodiesel usage, it is notable that the highest value was obtained by the B10 located at the flywheel and dynamometer with the value of 100.91dB and on the contrary, the lowest value could be obtained by the D100 with the value of 77.63dB located at the cylinder head. As can be summarized, different proportion of biodiesel could vary the noise level due to the changes of the fuel properties that influenced the combustion, mechanical and gas-flow noise in the engine

Spontaneous infection of a stable mediastinal cystic mass: A case report

Mediastinal cysts have an unpredictable course but can cause complications such as infection or local pressure effects. Persons with mediastinal cysts can be asymptomatic for many years or can develop symptoms as a result of complications of the cyst. There is a lack of consensus on the best approach to managing those patients without symptoms. In this case report, a 56 year old woman with an indolent mediastinal cyst initially managed conservatively suddenly developed symptoms suggestive of an infected mediastinal cyst requiring surgical resection

Cloud-To-Ground Lightning Flashes Under The Influence Of Pollution In Malaysia And Some Countries

The effect of air pollution produced from world war, industrial activities and transportation clearly can change the earth ecology system such as the atmospheric conditions. Base on few studies reported from by researcher in USA, Brazil, Spain and South Korea researcher have proven that the pollution effect can enhance the activity of lightning. Those information above motivate Advanced Multidisciplinary System Technology researcher in UTeM to report the cloud-to-ground lightning flashes in Malaysia the influence of pollution. Particulate Matter (PM10) and Sulfur Dioxide (SO2) concentration were used as gross indicator of Cloud Condensation Nuclei (CCN) and examined in relation to the urban increase in CG lightning activity. PM10 concentration recorded in Subang, Ipoh and Bayan Lepas were 51, 50 and 49μgm/m³ respectively. Meanwhile, SO2 concentration recorded were 8, 7.9, 7.7μgm/m³. The three urban areas have average number of CG lightning flashes of 200, 197 and 184. An analysis related number of CG flashes against pollutants show positive correlation in Malaysia with reading of 0.94. This indicates PM10 and SO2 concentration have high influential factor in enhancement of CG lightning activity in Malaysia

Permeance Based Algorithm For Computation Of Flux Linkage Characteristics Of Non-Linear 6/4 Switched Reluctance Motor (SRM)

The concept of permeance is used in the analysis of flux linkage of 6/4 SRM. The aim of this paper is to develop an efficient algorithm exploiting the nonlinear feature of the 6/4 SRM using the aforementioned concept of permeance. The first step is to generate the relevant equations related to permeances of the 6/4 SRM under study. The 6/4 SRM’s magnetization curve is then derived from the summation of mmf drops at various blocks representing the motor. The air gap permeances are derived at various angles and 3-D leakage effects are taken into account. These permeances are used for the mmf drop computation. The algorithm is capable of efficiently computing mmf drop at every block to consequently yield a complete accurate nonlinear flux linkage feature of the 6/4 switched reluctance motor. In this way, the capability of the SRM to produce the expected four times the specific output torque due to operation in high saturation region compared to an equivalent induction motor as special the attribute of the SRM is demonstrated

Comparison of Three Protocols: Dietary Therapy and Physical Activity, Acupuncture, or Laser Acupuncture in Management of Obese Females

AIM: The aim of this study was to compare efficiency of three types of obesity management protocols: dietary measures and physical activity; acupuncture or laser acupuncture with   healthy diet among obese females.SUBJECTS AND METHODS: Randomized longitudinal prospective study, carried out on 76 adult females. Blood pressure, anthropometric, ultrasonographic and biochemical assessments were done.RESULTS: Females undergo nutritional intervention showed highly significant improvement in the anthropometric measurements, visceral fat at umbilicus by US and diastolic blood pressure (decreased), and insignificant differences in fasting blood sugar and lipid profile. Female undergo acupuncture intervention showed highly significant improvement in visceral fat by US, lipid profile (decreased triglycerides, total cholesterol and LDL, and increased HDL), and decreased fasting blood sugar, and insignificant differences in the anthropometric measurements. Those undergo laser intervention showed highly significant improvement in all anthropometric measurements under study, visceral fat at umbilicus by US, blood pressure and some parameters of lipid profile (decreased total cholesterol and LDL). CONCLUSIONS: Nutritional intervention alone could be used to reduce weight if the lipid profile within normal range, but if it is impaired, acupuncture should be used beside. To strength the reduction in body anthropometry, laser intervention was recommended beside the nutritional intervention

Even-parity autoionizing states in the extreme-ultraviolet photoabsorption spectra of Mg, Al⁺, and Si²⁺

The dual-laser-produced plasma (DLP) photoabsorption technique has been used to study 2p→3s excitations in the isoelectronic species Mg, Al+, and Si2+ prepared in the excited configuration 2p63s3p. The autoionizing upper states belong to the 2p53s23p even-parity configuration. The versatility of the technique is demonstrated through a careful combination of space- and time-resolved photoabsorption scans. Plasma conditions optimized for the observation of the inaccessible parity regime were successfully reproduced along the isoelectronic sequence of interest. All the observed transitions were interpreted with the help of multiconfigurational atomic structure calculations. In the case of magnesium, the photoabsorption data are compared with the ejected-electron spectra excited by low-energy electron impact of Pejcev et al. [J. Phys. B 10, 2389 (1977)]

The impact of inflammation on bone mass in children

Bone is a dynamic tissue. Skeletal bone integrity is maintained through bone modeling and remodeling. The mechanisms underlying this bone mass regulation are complex and interrelated. An imbalance in the regulation of bone remodeling through bone resorption and bone formation results in bone loss. Chronic inflammation influences bone mass regulation. Inflammation-related bone disorders share many common mechanisms of bone loss. These mechanisms are ultimately mediated through the uncoupling of bone remodeling. Cachexia, physical inactivity, pro-inflammatory cytokines, as well as iatrogenic factors related to effects of immunosuppression are some of the common mechanisms. Recently, cytokine signaling through the central nervous system has been investigated for its potential role in bone mass dysregulation in inflammatory conditions. Growing research on the molecular mechanisms involved in inflammation-induced bone loss may lead to more selective therapeutic targeting of these pathological signaling pathways

Experimental investigation of vibrations and noise characterization for spark ignition engine

An experimental study was carried out for measuring vibrations, noise and combustion characteristics associated correlations using a four-cylinder spark ignition engine. This study aims to investigate the effects of vibrations and noise on spark-polishing machines that are triggered by pure gasoline. This test runs at 15% engine load and 20% with engine speed 1000-2200 rpm at intervals of 300 rpm. The measurement of engine vibration in pistonic uses PCB Piezotronics ICP® Accelerometer (352C22). Overall tests that have been carried out for 20% loads at 1900 and 2200 maximum vibrations, the velocity is 0.214 and 0.234, compared to 0.617 and 0.562 for 15% loads. From the results of engine vibration analysis, it can be reported that increasing engine speed and the load is given engine vibration can significantly decrease. Generally, noise increases for all samples tested; however, reduced noise is recorded when speed and engine load increase. This observation is also consistent with other observations related to vibration and combustion noise, heat release rates, and ignition delays

Experimental Study of the Vehicle Dynamics Behavior during Lane Changing in Different Speeds

During lane changing, the speed of the vehicle is related to the stability of the vehicle. If the driver changes the lane at a high speed, the vehicle will lose its stability and it can increase the possibility of an accident. In this study, the experiment has been developed to analyse how the speed of the vehicle can affect the vehicle dynamics behavior. To achieve this objective, the UMP Test Car which employed with global positioning system (GPS), steering torque and angle sensor, displacement sensor and gyro sensor is used in the experiment. The experiment is run at the UMP test track and the track has 2 lanes which can allows the vehicle to change the position from the left to the right. In the experiment, when the GPS monitor shows 30 km/h, the driver will maintain the speed and start to turn the steering just after the test car reaches to the first skittle. Then, the driver will turn again the steering when the test car reaches to the second skittle. This method is repeated two times and the same methods is used for the speed 50 km/h. The data from the sensors is recorded in the Dewetron software and the graph is plotted. From the experimental results, the steering angle, steering torque, yaw rate and displacement for the speed 30 km/h is smaller than 50 km/h. It means that during lane changing, the speed 30 km/h is more stable compared with 50 km/h