Індекс рубрикатора НБУВ: Н761.204.42

Рубрики:

Біологічні методи очищання стічних вод у штучних умовах

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: Л111.3

Рубрики:

Перемішування. Гомогенізація

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: Н581.30

Рубрики:

Методи зміцнення ґрунтів

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

Public transport safety is still an issue that needs to be studied by bureaucrats and researchers. This is because public bus accidents are still quite high. This is because many families, involved in traffic accidents, are shocked by the accident. Therefore, the problem of perception of a safe bus needs to be studied. The purpose of this study was to determine the perception model of a safe public bus. Mathematical modeling based on the parameters that have been studied was selected first. While the second objective was to determine the importance value of the parameters that are an indication of the perception of the safety of intercity bus public transportation. This research is a type of perceptual one where the data is taken from the relevant respondents. The method of data collection was carried out using a questionnaire with respondents from bus company owners, drivers, and passengers in the province of East Java, Indonesia. Respondents were asked to answer questions related to the variables of income, speed, comfort, and safety. The method of conjoint analysis is used. The first stage is the result of modeling the perception of a safe bus. Further analysis is carried out to obtain the importance value of the parameters. The result of this research is a utility model for the perception of a safe bus, which is expressed by the equation U, where the variables include income, speed, comfort, and safety. The highest level of importance is income 33,29 %, followed by the security variable with a weight of 25,39 %. This shows that the income factor is a top priority for drivers and management of bus company owners, while road safety is second only to income. In other words, respondents' perceptions are more concerned with income, while safety is still a non-priority factor.

Індекс рубрикатора НБУВ: О35-046

Рубрики:

Автотракторні двигуни (автомобільні та тракторні двигуни)

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

The demand for self-compacting concrete is very high because this concrete has high flowability and has resistance to segregation. Natural aggregates are of high value, while concrete demolition materials are abundant and of low value. So that the recycled coarse aggregate can be used as concrete material, this study analyzes the characteristics of Self Compacting Concrete (SCC) using recycled coarse aggregate from construction waste. Tests for aggregate wear, aggregate hardness, compressive strength of concrete and tensile strength of concrete were carried out. The wear test refers to the standard AASHTO T-96-74, ASTM C-131-55 and SNI 2417-2008. This test uses recycled coarse aggregate that has been washed so that the sludge content is clean; after that, it was baked with the used aggregate, the aggregate that passed the 12,5 mm sieve and was retained in the 9,5 mm sieve. The test object is pressurized 40 tons at a speed of 4 tons/minute. Concrete Compressive Strength Test refers to SNI 03-1974-2011, using a scale with an accuracy of 0,3 % of the weight of the concrete, a concrete press machine and a capping machine. While the split tensile strength test of concrete refers to SNI 03-2491-2014, carried out on days 7, 21 and 28 with a cylindrical test object. Variations of recycled aggregates start from 0 %, 25 %, 50 %, 75 %, and 100 %. The design's compressive strength is 25 MPa. The results showed that the recycled aggregates had good gradation, high absorption and low specific gravity compared to natural aggregates. The recycled coarse aggregate reduces the compressive strength of the concrete and causes a decrease in a slump, thereby reducing the split tensile strength of the concrete.

Шифр НБУВ: Ж24320 Пошук видання у каталогах НБУВ 

The increasing demand for diesel fuel causes high levels of air pollution, noise, and vibration. Therefore, we need a mixture of materials that can reduce the environmental effect with low vibration. The purpose of this study was to investigate the effect of a diesel-essential oil mixture on a diesel engine, related to engine performance, noise, and vibration. The research was conducted using a 402 CC Dongfeng diesel engine, a mixture of diesel and essential oils with a percentage of 5 %, 10 %, 15 %, 20 %, engine speed of 1,300 rpm, 1,500 rpm, 1,700 rpm, 1,900 rpm. The noise intensity test uses a sound level meter at 30 - 130 dBA with a frequency between 20 - 20,000 Hz. To test the density of smoke, a smoke tester was used. Meanwhile, to measure the rotational speed of the engine, a DT 2234L type tachometer was used. A digital stopwatch was used to measure the processing time with an accuracy of up to 0,01 s. Besides that, a strain gauge was also used to detect vibrations. A measuring cup was used to measure the volume of the mixture of fuel and essential oils. The results showed that in the B10 mixture at 1,300 rpm engine speed, the largest fuel consumption time was 155 s. While the smallest fuel consumption time is found at 1,900 engine speed, which is 106 s. The lowest percentage of exhaust emissions is in the B20 mixture, which is 56,8 %. While the largest percentage of exhaust emissions is in B0 with a value of 79,8 %. The lowest noise value is in the B10 mixture at 1,300 rpm engine speed, which is 105,7 dB. While the highest noise value is at 1,900 engine speed, which is 112,3 dB. The lowest vibration is in the B10 mixture with an engine speed of 1,300 rpm, which is 975,7 Hz. While the highest noise value is in the B10 mixture with 1,900 engine speed, which is 989,8 Hz.