scholarly journals Pengukuran Kecepatan Suara dalam Media Air Menggunakan Sensor Ultrasonik

Author(s):  
Miftakhul Khanan ◽  
Ahmad Ashari

 The speed of sound in water varies depending on the condition. There are several factors that affect the difference in the speed of sound in water, such as the viscosity, temperature, pressure, etc. In this study, designed a tool to measure the speed of sound in water by utilizing ultrasonic waves.The ultrasonic sensor used consists of transmitter and receiver. The method used is indirect method by using sound reflection. The 40kHz ultrasonic wave used on the transmitter is generated by the AD9850 signal generator. Signals received receiver in and processed on a microcontroller through an LM393 comparator that makes the signal HIGH and LOW so it can be read directly on the digital pins of microcontroller.Measurements were made at a water temperature of 27oC with 1 meter test medium. The measurement is done on variation of distance from 5-90 cm with span of 5 cm. By knowing the time difference between the transmitted and received signal and the known wave range, the speed of sound in the water obtained in the study was (1394 ± 27) m / s with the determination coefficient of 0.998.

2018 ◽  
Vol 13 (2) ◽  
Author(s):  
Gaurav Kumar ◽  
Veena Pande ◽  
Shweta Pasi ◽  
Vijay P. Ojha ◽  
Ramesh C. Dhiman

The present study was planned to characterize the microclimate experienced by Aedes larvae in different breeding habitats by determining the temperature variations in water kept in containers during different months under natural conditions. The study was conducted in three municipal zones of Delhi. In each site, four types of container material (plastic, cement, iron and ceramic) were chosen for recording the water temperature in the containers. Daily air and water temperatures (mean, maximum and minimum values) recorded by HOBO and Tidbit data loggers, respectively, were compared using analysis of variance and Tukey’s honest significant difference (HSD) tests. Mean monthly temperature of water varied from 16.9 to 33.0 °C in tin containers, 17.3 to 35.6°C in plastic containers, 14.3 to 28.5°C in ceramic pots, 23.3 to 30.4°C in cemented underground tanks (UGT) and 15.8 to 35.1°C in cemented overhead tanks (OHTs). Corresponding values for the air temperature ranged from 17.7 to 36.1°C. The difference between temperature of water in the containers and air temperature was highest for ceramic pots. Daily mean, maximum and minimum temperatures recorded by different data loggers differed significantly (P<0.05). When Tukey HSD test was applied for data analysis, the daily mean air temperature differed significantly from the water temperature in tin and ceramic pots as well as cemented OHTs. The temperature of water in the different breeding habitats investigated was lower than the air temperature. Moreover, actual air temperature as recorded by HOBO was higher than the temperature recorded by local weather stations. Considering the ongoing climate change, cemented UGT and earthen pots may be more productive breeding habitats for the Aedes mosquito in the near future, while plastic and cemented OHTs might no longer be suitable for Aedes breeding.


2019 ◽  
Vol 10 (04) ◽  
pp. 651-654
Author(s):  
Anmar Sael Hussein ◽  
Saja Jamal Noman

In this quantitative examination of melanin was detected in 41 isolates of fumigatus. It was found that the significance of the difference in which the production of melanin (p ˂ 0.001) was the range of melanin extracted from fumigatus between (1.2 - 3.1 mg/mL). The isolates AFU1, AFU14, AFU29, AFU30, and AFU41 indicated that the maximum production ranged between (2.9-3.1 mg/mL). 2 hours at 100°C. It has similarities with standard melanin characters, and the same chemical characters of melanin extracted from the hymen of Bjerkandara adusta have been achieved according to a study (14) meaning there is similarity with standard melanin. The overlay of IR spectra of synthetic melanin extracted from fungal cultures showed a high degree of similarity. Purification of melanin from A. fumigatus. Wave numbers shown in 3381, 2927, 1867, 1531, 1404, 1073 and 651 cm-1 The wave range can be traced to the following chemical groups: 3381 cm-1 attributed to OH bonds, 2927 cm-1 to HC or HC = 0 bonds 1404 (C-CH3), and 651 cm -1 to (acyclic) CH2 bonds.


1968 ◽  
Vol 19 (2) ◽  
pp. 183-191 ◽  
Author(s):  
R. J. Stalker

SummaryA probe is described which will detect contamination, by driver gas, of the test section flow in a shock tunnel. It is a continuously sampling device, which responds to the difference between the ambient speed of sound in the driver gas and the test gas. The probe is compact, easy to construct, and can be used for detection of driver gas in routine testing. The theory of the probe is explained, and experiments are reported which confirm its effectiveness.


2013 ◽  
Vol 461 ◽  
pp. 531-534
Author(s):  
Yu Zhu ◽  
Zhe Xin Han ◽  
Peng Kun Sun ◽  
Tian Hao Wang ◽  
Yin Han Gao

Based on the characteristic of an ultrasonic sensor that can sense the external environment, we design an intelligent vehicle with obstacle avoidance function. First, we use MSP430 as the core of the design system. Second, we distribute the ultrasonic sensor evenly on the round zone of the obstacles to process the data and ambient temperature, which is transmitted from the ultrasonic receiver through the SCM (what is SCM, explain). Finally, we make it to realize the functions of intelligent controlling and avoiding obstacles automatically.


Author(s):  
Adel Akair ◽  
Hesham Baej

The cycles’ structure was based on recently published technical information of low-temperatures powered Ammonia-water (NH3-H2O) absorption chiller.  The cycle was completely modeled using different components available within the refrigeration library of IPSEpro software package.  Using the model a cold-water ammonia-water absorption chiller was examined and validated in accordance to the relevant thermodynamic laws and charts. A low-grade temperature solar resource was modeled to energise the proposed model. For water-cooled cycles, the rejected heat from the absorbers and the condensers was carried out by water, at an average fixed temperature of 25°C, pumped out from ground water. The results obtained show that when the Coefficient of performance (COP), heat inputs into the generator, and cooling mass flow rates are fixed, the cycle parameters are highly affected by variation of coolant temperature. For instance when cooling water temperature decreases. Also when cooling water temperature increase, the cycle pressure, usable chilled water temperature difference and desorber outlet temperature increase whereas mass concentration and refrigeration capacity decrease. The effectiveness of the generator inlet temperature (solar source) is a factor of the largest effect to the COP. The difference was 0.1401, 27.4%. The chilled water inlet temperature (underground water) is the second largest effect to the COP. The difference between the maximum and the minimum value is 0.0865 and the relative difference is 18.9% with cooling capacity 12 kW. The influence of evaporator temperature to the COP is also minimal with only 2.2% difference. The influence of absorber temperature and condenser temperature to the COP are almost identical, the relative difference is 19.2% and 18.9% respectively.


Author(s):  
Stefanija MISEVIČIENĖ

The quality of water in rivers of central Lithuania is often bad due to intensive anthropogenic activities. When rivers flow through the town’s territory, concentrated pollution, such as rainwater, industrial and productional waste water discharges, contributes to diffuse sources of pollution. If biogenic substances are the main indicators for diffuse pollution, organic matter, expressed as BOD, is the indicator for concentrated pollution. The article provides the 2013 – 2017 monitoring data on the changes of organic matter in the water of the Dotnuvele and Smilga Rivers and discusses the reasons for fluctuations in concentrations of BOD7. The aim of the research is to investigate the changes in the organic matter of the Dotnuvele and Smilga Rivers, depending on meteorological factors. For chemical analysis, water samples were taken quarterly. Water analysis was carried out by the ASU Chemical Analytical Laboratory of Water Resources Engineering Institute. The amount of organic matter (BOD7) is calculated as the difference in oxygen content after 7 days of incubation, while the amount of dissolved oxygen (O2) in the water is determined by the electrochemical probe method. The concentrations of BOD7 and O2 in the water of both rivers is compared with the criteria for assessing the ecological status of surface water bodies. The research has shown that the dissolved oxygen concentrations in rivers’ water are strongly influenced by water temperature and precipitation. The lower the temperature, the more of the dissolved oxygen is found in rivers’ water (r = -0.64). A lower precipitation amount, which reaches the rivers, increases the amount of dissolved oxygen in them (r = -0.45). The increase of BOD7 concentrations in rivers’ water was caused by higher precipitation amount (r = 0.46), higher air (r = 0.41) and lower water temperature (r = -0.41). The ecological status of the Dotnuvele River was usually good, while Smilga was average.


Author(s):  
Tatsunori Yamaki ◽  
Yutaka Abe ◽  
Akiko Kaneko ◽  
Tomoomi Segawa ◽  
Koichi Kawaguchi ◽  
...  

In the Microwave Heating de-nitration (MH) method developed in Japan, a mixed solution of uranyl nitrate and plutonium nitrate (Pu/U mixed nitrate solution) recovered from the spent fuel in the reprocessing plant is converted directly to mixed oxide (MH-MOX) powder. This MH-MOX powder is utilized to fabricate MOX fuel with UO2 powder for FBR. The MH method is accompanied with transient boiling phenomena such as overflow and flushing. Toward high-speed and high-capacity conversion by MH-method in the future, it is required to avoid overflow and flushing and to understand optimal conditions for vessel shape design and microwave output operation. The objective of this paper is to elucidate occurrence criteria of flushing phenomena. At the first step for this objective, basic knowledge of transient boiling phenomena by the MH-method has been mainly acquired with using distilled water. From the results, it is observed that generation of singular bubble triggers flushing and distilled water just before flushing is superheated more than 10 °C in conditions that flushing is confirmed. Also, the water temperature reaches its peak, and it is almost unchanged in conditions that flushing is not confirmed. In no flushing conditions, it is found that the evaporation starts from the point where the water temperature reaches its peak, and water level is decreased gradually. Thus, the difference of thermal characteristics greatly affects whether flushing occurs. The second step, by focusing on the process before flushing occurs, we investigate flow structure, and heat amount through the temperature distribution inside the jelly just after microwave heating. Potassium chloride (KCl) aqueous solution and water are used. KCl solution is electrolyte solution same as reprocessing solution. From the results, upward flow is observed near the center of the solution in the case of the water just after microwave heating. On the other hand, downward flow is observed in the case of KCl solution. As a result of temperature distribution, the water is heated its near center, and KCl solution is heated the around. Thus, it is considered that heat amount of microwave varies depending on solution characteristics, and the difference greatly affects the flow structure. The heat amount and flow structure are critical factors that can determine transient boiling phenomena. We need to investigate transient boiling phenomena of KCl solution in the future.


1970 ◽  
Vol 53 (4) ◽  
pp. 804-807
Author(s):  
J T Gillingham ◽  
D A Colby

Abstract Selected stock feeds were analyzed for crude fat by the direct (AOAC 22.033) and the indirect (AOAC 22.034) methods. The direct method invariably yielded lower values (about 2% crude fat), due to instability of solvent extractives at 100°C during drying. The difference between the methods was greatest for silages (about 4.5% crude fat) and it was shown to be due to volatilization of organic acids during drying of the solvent extractive. The authors claim that the indirect method is the better approach to valid crude fat determinations. Vacuum drying (22.003) of oil seeds and silage preparatory to extraction was found to effect a weight loss, exclusive of moisture, either by volatilization or decomposition of heat-labile compounds. Titratable organic acids in silages decreased as a result of vacuum drying. It is claimed that preliminary drying of stock feeds, especially silage, should be accomplished by drying over H2SO4 (22.007) or by freeze-dry ing.


2001 ◽  
Vol 61 (2) ◽  
pp. 323-327 ◽  
Author(s):  
M. S. PINHEIRO ◽  
R. ANDREOTTI E SILVA ◽  
S. A. SANTOS

Three options of water temperatures in a thermal gradient that changed from 22 to 35°C were offered to Pantanal caiman (Caiman croocodilus yacare) hatchlings. Animals from two nests were submitted to temperatures during 19 days (Nest 1 - 20 caimans caught in the nature hours after hatching), corresponding to 1 to 7 observations periods, and 13 days (Nest 2 - 20 animals obtained by artificial incubation) relative to observation period 8. Caimans remain fasting during experimental period. Hatchlings were allocated in a enclosure containing three styrofoam boxes (120 L) disposed side by side enclosed by wire netting and filled with water to the top. Thus, the animals were free to access the boxes, which temperatures were changed at the end of each observation period to avoid position effects. Air temperature was keep close to 22°C by air conditioning and water temperature was controlled by thermostats. The trial was divided in three phases determined by elimination of the less frequented temperature and its substitution by another temperature. In a first phase of the experiment that contained 1, 2 and 3 observation periods, the thermostats were regulated to 22°C (BoxD), 26°C (BxC) and 32°C (BxA). In phase 2 to 26°C, 29.5°C (BxB) and 32°C, including 4, 5 and 6 periods. In the third phase that included 7 and 8 periods, the thermostats were adjusted to 29.5°C, 32°C and 35°C (BxE). The number of caimans in each box was recorded two to three times a day (8:00, 14:00 and 17:00h) before pointed water temperature. Mean water temperatures (+ standard deviation) and respective caiman frequency means by box/temperature were: Phase 1 (BxD/22.3 ± 1.2°C - 10.3%; BxC/27.0 ± 2.4°C - 32.0% and BxA/31.2 ± 1.1°C - 57.6%); Phase 2 (BxC/26.6 ± 2.8°C - 13.3%; BxB/29.3 ± 2.2°C - 27.7% and BxA/31.3 ± 1.2°C - 59.0%) and Phase 3 (BxB/29.5 ± 3.6°C - 23.7%; BxA/31.0 ± 2.2°C - 31.9 and BxE/34.0 ± 2.2°C - 44.4%). Observing that in the phases 1 and 2 the box with hottest water (CxA) was more frequented. In the phase 3, the difference between higher and smaller frequency straiten to 20.7%, in relation to almost 46.5% in phases 1 and 2, indicating that water temperatures between 29.5 and 35°C resulted in body temperatures more next to the comfort zone, in the experimental conditions.


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