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The effect of separated expansion chamber parameters on exhaust pressure oscillations in single cylinder motorcycle engine
2020
Banis, K., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Engineering
This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.
Показать больше [+] Меньше [-]Temperature and weight monitoring of the Apis Cerana bee colony Indonesia
2020
Kviesis, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Information Technologies. Dept. of Computer Systems | Zacepins, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Information Technologies. Dept. of Computer Systems | Komasilovs, V., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Information Technologies. Dept. of Computer Systems | Paramita, A.M., Labtek Indie, Bandung, West Java (Indonesia) | Muhammad, F.R., Labtek Indie, Bandung, West Java (Indonesia)
Remote and automatic monitoring of two Apis Cerana bee colonies was conducted in Indonesia to demonstrate precision beekeeping approach in that region. Successful implementation of the precision beekeeping system includes development of the bee colony monitoring hardware and software for data collection, analysis and visualisation. This paper focuses on development and installation of such systems at the private apiary in Indonesia. For bee colony monitoring at the apiary a developed monitoring unit was used, which is based on ESP microchip, and for the data storage SAMS data warehouse was used. The monitoring results showed that the choice of the location of the temperature sensor is important, as the temperature at the hive sides changes synchronously with the outside temperature. Also, feedback from the beekeeper is collected to further improve the system and monitoring process. This research is conducted within the SAMS – Smart Apiculture Management Services project, which is funded by the European Union within the H2020-ICT-39-2016-2017 call and with close collaboration with the local private beekeeper. To find out more, visit the project website https://sams-project.eu/.
Показать больше [+] Меньше [-]The characteristics of extruded faba beans (Vicia faba L.)
2016
Strauta, L., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology | Muizniece-Brasava, S., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology
Faba beans (Vicia faba L.) are an excellent protein source and should be more present in human diet, but due to their long cooking time, they are rarely used. So, in order to increase the accessibility of faba beans (Vicia faba L.), experiments were carried out to obtain new food products. Extrusion-cooking was chosen as the potential thermal cooking process and two different products were obtained. One was made exclusively from faba bean (Vicia faba L.) flour, while the second one was produced with a 50% addition of wheat flour to bean flour. Protein content, size, volume mass, pH and starch content for obtained products were analysed in order to characterise the products, as well as to see the differences from non-extruded faba beans (Vicia faba L.) and obtained samples. The experiments were carried out using faba beans (Vicia faba L.) obtained at Ltd. “Pure Horticultural Research Centre”. They were milled at Ltd. “Grauda spēks” and extruded with a twin screw extruder at Ltd. “Milzu”. The experiments showed that the extrusion process had decreased the protein content by 9%, but the starch content had risen by 13% with the addition of wheat flour. But, for sample, without added wheat flour differences were not significant. No significant size differences were observed in the obtained samples and pH values had no significant differences between extruded samples.
Показать больше [+] Меньше [-]Fault diagnosis of low-power three-phase induction motor
2016
Gedzurs, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Engineering
An induction motor reliability survey at an egg processing plant shows that almost 50% of the total motor failures are fan induction motors. Visual investigations of the faulty fan motors show that the main cause of the induction motor failure is air gap eccentricity. In this study, experimental tests are performed on a 1.1kW three-phase induction motor to detect air gap eccentricity and overheating of the induction motor. Heating tests show that end shield housing temperature reaches 100°C with blocked air flow from the fan, which can reduce the lifespan of the bearing. Dimension measurements of the end shield housing show that the dimensions of both tested motors back-end shields are larger than ISO tolerance grade limit. It leads to a loose fit between the housing and bearing, causing air gap eccentricity. Also, both motor back end shield housing has an out-of-round condition leading to an unbalanced magnetic pull. To detect the air gap eccentricity caused by too loose of a fit between housing bore and bearing, current Park’s vector approach is used. To measure three phase current, Hall Effect current transducers, a digital oscilloscope is used and Matlab software to process the measurement data. Results show that Park’s vector approach can be used to detect the air gap eccentricity caused by too loose a fit between bearing and housing. Therefore, the Park’s vector approach can be used to diagnose air gap eccentricity and analyse the type of the air gap eccentricity.
Показать больше [+] Меньше [-]Purification of crude glycerol derived from hydrogenated cottonseed and its use in confectionary products
2024
Ruzibayev, Akbarali | Abdurakhimov, Ahror | Calvo-Gomez, Octavio | Akhmedova, Shahlo | Kurambayev, Sherzod
Glycerol is a versatile substance used in food, beverages, cosmetics, and technical applications. It can be derived from fats and oils through 4 different reactions, including: transesterification, directed hydrogenation, hydrolysis, and saponification. Glycerol derived from fat hydrolysis yields superior quality and quantity when compared to saponification. The resulting glycerol water is purified and concentrated through evaporation to yield crude glycerol with a concentration of 86–88%. Two distinct methods are recognized for further improving quality of glycerol: distillation, and the purification of glycerol water through the ion exchange process followed by evaporation. The goal of this research was to improve the purification process of glycerol, for obtaining premium-quality glycerol without the need for distillation, through the utilization of cations. Several combinations of activated carbon and clay were tested, and it was determined that a combination of 70:30 yielded the optimal results, considering the amount of glycerol and ash content. Technological parameters such as reaction durations, pH, and process temperatures were investigated, and it was discovered that the appropriate combination was a process duration of more than 40 minutes, a pH value of 2, and a temperature of 70 °C. Besides, it was also determined that the concentration and quality of glycerol derived from cottonseed oil can be enhanced through distillation or purification with cationite. Moreover, different concentrations of glycerol on the elaboration of gingerbread were tested, and the conclusion is that adding 5% of the resulting glycerol to the gingerbread recipe could ensure better preservation of its quality during its shelf life.
Показать больше [+] Меньше [-]Sound absorption properties of the patented wood, lightweight stabilised blockboard
2023
Roziņš, Rihards | Brencis, Raitis | Spulle, Uldis | Spulle-Meiere, Ivanda
It is well known that wood tends to shrink and swell as the relative humidity of the air changes. There have been, and still are, attempts to make dimensionally stable wood panels such as Dendrolight®. The physical-mechanical, operational, including acoustic, properties of this material have been significantly improved compared to traditional wood-based panels. However, the production of this material requires very specific processing equipment and a large energy investment. The developers of this material in Latvia invented and patented wood, Lightweight Stabilised Blockboard (LSB). In order for this material to be used in the production of various products, it is necessary to clarify its characteristic, technological, as well as operational properties. The study gathers information about the sound absorption properties of various natural and wood materials, characteristics, and the sound absorption of the studied material at different sound frequencies. The reviewed sources of information indicate that nowadays there are still problems in sound conduction and absorption and isolation issues are being addressed in building acoustics. The production of samples and the determination of sound absorption were carried out using a developed methodology developed in accordance with regulatory requirements. The data obtained in the practical study were compared with the relevant indicators of the Dendrolight® and wood-based panels used for building structures and to determine their compliance with the requirements set forth in the standards ISO 10534-2 and ISO 11654. Research data show that LSB corresponds to E sound absorption class in some of the investigated frequencies.
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