scholarly journals Relationship of Lagrangian microscopic energy efficiency of a gas parcel in a thermoacoustic engine to macroscopic one

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045106
Author(s):  
Kyuichi Yasui
2019 ◽  
Vol 62 (2) ◽  
pp. 491-500 ◽  
Author(s):  
Maria Ledinek ◽  
Leonhard Gruber ◽  
Franz Steininger ◽  
Birgit Fuerst-Waltl ◽  
Karl Zottl ◽  
...  

Abstract. The aim of this study was twofold: first, to evaluate the influence of body weight on the efficiency of dairy cows, and second, to analyze the current state of dairy cattle populations as part of the Austrian Cattle Breeding Association's Efficient Cow project. Data of Fleckvieh (FV, dual-purpose Simmental), Fleckvieh×Red Holstein (FV×RH), Holstein (HF) and Brown Swiss (BS) dairy cows (161 farms, 6098 cows) were collected at each performance recording during the year 2014. In addition to routinely recorded data (e.g., milk yield, fertility), body weight, body measurements, body condition score (BCS) and individual feed information were also collected. The following efficiency traits were considered: body weight efficiency as the ratio of energy-corrected milk (ECM) to metabolic body weight, feed efficiency (kilogram ECM per kilogram dry-matter intake) and energy efficiency expressed as the ratio of energy in milk to energy intake. The relationship of milk yield to body weight was shown to be nonlinear. Milk yield decreased in cows above the 750 kg body weight class for HF, BS and FV×RH with 68 % RH genes, but less dramatically and later for FV at 800 kg. This resulted in an optimum body weight for feed and energy efficiency. BS and HF had the highest efficiency in a narrower and lighter body weight range (550–700 kg) due to a stronger curvature of the parabolic curve. Contrary to this, the efficiency of FV did not change as much as it did in the dairy breeds with increasing body weight, meaning that FV had a similar feed and energy efficiency in a range of 500–750 kg. The breed differences disappeared when body weight ranged between 750 and 800 kg. The average body weight of the breeds studied (FV 722 kg, BS 649 and HF 662 kg) was in the optimum range. FV was located at the upper end of the decreasing segment. In conclusion, an optimum body weight range for efficiency does exist, due to the nonlinear relationship of milk yield and body weight. Specialized dairy breeds seem to respond more intensively to body weight range than dual-purpose breeds, due to the stronger curvature. Cows with medium weights within a population are the most efficient. Heavy cows (>750 kg) produce even less milk. A further increase in dairy cows' body weights should therefore be avoided.


2019 ◽  
Vol 7 (12) ◽  
pp. 425 ◽  
Author(s):  
Ren ◽  
Ding ◽  
Sui

With the increasingly strict international GHG (greenhouse gas) emission regulations, higher requirements are placed on the propulsion system design of conventional ships. Playing an important role in ship design, construction and operation, ship–engine–propeller matching dominantly covers the CO2 emission of the entire ship. In this paper, firstly, a ship propulsion system matching platform based on the ship–engine–propeller matching principle and its application on WinGD 5 × 52 marine diesel engine have been investigated. Meeting the energy efficiency design index (EEDI) regulation used to calculate the ship CO2 emission is essential and ship–engine–propeller matching has to be carried out with EEDI into consideration. Consequently, a procedure is developed combining the system matching theory and EEDI calculation, which can provide the matching results as well as the corresponding EEDI value to study the relationship between EEDI and ship–engine–propeller matching. Furthermore, a comprehensive analysis is performed to obtain the relationship of EEDI and system matching parameters, such as ship speed, effective power and propeller diameter, reflecting the trend and extent of EEDI when changing these three parameters. The results of system matching parameters satisfying different EEDI phases indicate the initial value selection in matching process to provide reference for the design of ship, engine and propeller under the EEDI regulations.


Author(s):  
N. Ostrovskaya ◽  
◽  
S. Barykin ◽  
K. Borodina ◽  
◽  
...  

In the article, the authors consider the main provisions of the concept of «quality». Make a connection between quality and safety, which is important for smart city projects and energy conservation. The article discusses the relationship of quality management with energy conservation, energy efficiency and energy services


2014 ◽  
Vol 981 ◽  
pp. 769-773
Author(s):  
Su Lu Zheng ◽  
Yun Yan Mao ◽  
Xiang Ping Wang ◽  
Zhi Yun Zheng ◽  
Shen Xi He ◽  
...  

In the paper,the relationship of the energy efficiency and its impact factor such as intake valve lift ,exhaust valve lift, clearance volume and rotational speed has been researched and the optimal conditions of the air compressor running was found . By adjusting the parameters of intake valve lift, exhaust valve lift, clearance volume and rotational speed, the total energy of a W-1.6/5 compressor could be reduced by 10.9%.


Author(s):  
S. L. Rovin ◽  
L. E. Rovin ◽  
L. N. Rusaya ◽  
O. V. Gerasimova

The article studies the issues of dust and gas cleaning of emissions from smelting units, the analysis of the relationship of furnaces energy efficiency and their environmental parameters, the complex systems that insure high efficiency of gas purification which are aspirated from the melting units are provided, with minimal energy and investment costs.


2011 ◽  
Vol 317-319 ◽  
pp. 1462-1473
Author(s):  
Dong Xu ◽  
Da Qiang Cang ◽  
Li Xue Qin ◽  
Jian Feng Duan

The mixing effect in steel converter process is very important to the fluid flow and mass transfer in bath and directly affects the chemical reaction and temperature homogeneity in the industry steel process. The cold model was employed to research the relationship of mixing time, agitation power, lance type, operation parameters, bath shape et al. According to the results, the mixing time of the bath decreases with larger gas flow rate and bigger diameter of the bath. Increasing the nozzle inclination properly is benefit for decreasing the mixing time and improving the agitation of the bath. The relationship of mixing time and lance height is complicated, because the mixing time is fluctuant by the lance rising. By introduce the relative energy utilization factor, the agitation power utilization was analyzed and compared under different conditions. The energy efficiency is higher with larger nozzle inclination as well as the bigger ratio of diameter and depth of the bath.


2013 ◽  
Vol 448-453 ◽  
pp. 3386-3391
Author(s):  
Qian Wang ◽  
Qing Lin Meng

Room air conditioner is widely used in a single room or other enclosed spaces to increase the comfort of the environment. It adjusts the temperature and humidity to maintain the comfort for humans; dehumidification is a very important function of room air conditioner. This paper demonstrated the relationship among dehumidification capacity, entering air parameters, and evaporative temperature, presented the calculation method of maximum condensate water flow rate in certain condition, discussed the interaction of energy efficiency ratio and dehumidification capacity, and gave the relationship of condensate water flow rate and evaporative temperature using a specific compressor model. It is suggested that a balance should be made between dehumidification capacity and energy efficiency ratio for room air conditioner operating requirement.


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