MODELLING PROTEIN AND LIPID GAINS IN GROWING PIGS EXPOSED TO LOW TEMPERATURE

1982 ◽  
Vol 62 (1) ◽  
pp. 109-121 ◽  
Author(s):  
P. A. PHILLIPS ◽  
F. V. MacHARDY
Keyword(s):  
Low Temperature ◽  
Energy Conversion ◽  
Energy Conversion Efficiency ◽  
Growing Pigs ◽  
Extended Model ◽  
Feeding Level ◽  
Model Predictions ◽  
Key Words Pig ◽  
Conversion Efficiencies ◽  
Environmental Temperatures

An existing energy partition model that relates protein and lipid retention in growing pigs (60 kg) to dietary energy intake was extended to include environmental temperature. The extended model for 45- to 75-kg pigs can be used to predict animal heat production at each feeding level, lower limit of the zone of thermoneutrality at each feeding level and incremental energy conversion efficiency over a range of feeding levels and environmental temperatures. The model predictions were validated in two ways. (1) Incremental energy conversion efficiencies over a range of feeding levels and environmental temperatures, as determined in three studies cited in the literature, were compared against the energy conversion efficiencies predicted by the model. (2) The rates of protein deposition and liveweight gains in growing pigs housed at 21 °C and 6 °C, were compared against the model predictions. While the model should receive further testing, both the above tests confirmed that low temperature can be related to feeding level and rates of tissue gain in pigs in a predictable manner. Key words: Pig, temperature, model, energy retention

scholarly journals Analysis and optimal design of a vibration isolation system combined with electromagnetic energy harvester

2019 ◽  
Vol 30 (16) ◽  
pp. 2382-2395
Author(s):  
Uchenna Diala ◽  
SM Mahdi Mofidian ◽  
Zi-Qiang Lang ◽  
Hamzeh Bardaweel
Keyword(s):  
Energy Harvesting ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Vibration Isolation ◽  
Energy Conversion Efficiency ◽  
Isolation System ◽  
Magnetic Components ◽  
Energy Harvesting System ◽  
Response Function Method ◽  
Conversion Efficiencies

This work investigates a vibration isolation energy harvesting system and studies its design to achieve an optimal performance. The system uses a combination of elastic and magnetic components to facilitate its dual functionality. A prototype of the vibration isolation energy harvesting device is fabricated and examined experimentally. A mathematical model is developed using first principle and analyzed using the output frequency response function method. Results from model analysis show an excellent agreement with experiment. Since any vibration isolation energy harvesting system is required to perform two functions simultaneously, optimization of the system is carried out to maximize energy conversion efficiency without jeopardizing the system’s vibration isolation performance. To the knowledge of the authors, this work is the first effort to tackle the issue of simultaneous vibration isolation energy harvesting using an analytical approach. Explicit analytical relationships describing the vibration isolation energy harvesting system transmissibility and energy conversion efficiency are developed. Results exhibit a maximum attainable energy conversion efficiency in the order of 1%. Results suggest that for low acceleration levels, lower damping values are favorable and yield higher conversion efficiencies and improved vibration isolation characteristics. At higher acceleration, there is a trade-off where lower damping values worsen vibration isolation but yield higher conversion efficiencies.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

Air-Steam Gasification of Dairy Biomass Using Small Scale Fixed Bed Gasifier

2009 ◽  
Author(s):  
Gerardo Gordillo ◽  
Kalyan Annamalai
Keyword(s):  
Energy Conversion ◽  
Fixed Bed ◽  
Energy Conversion Efficiency ◽  
Steam Gasification ◽  
Small Scale ◽  
Gasification Process ◽  
Green Power ◽  
Endothermic Process ◽  
Conversion Efficiencies ◽  
Rich Mixtures

The composition of gases obtained from gasification of biomass fuels depends principally upon parameters like fuel and oxidizing medium supplied, equivalence ratio (Φ), steam-fuel ratio (S:F), pressure, reaction temperature, and residence time in the gasifier. Gasification with steam only is an endothermic process which produces rich mixtures of CO and H2 while gasification with air-steam may not require heat input in order to produce H2 rich mixtures of CO and CO2. Furthermore, gases produced by gasification with-air-steam can be supplied to a shift reactor to produce mixtures of H2, CO2, and N2. When pure O2 is used instead of air, the H2 separated from CO2 can be used for in situ sustainable green power generation. The gasification process can handle low quality fuel and larger sized particles. While coal has higher fixed carbon (FC) providing more heat for gasification, the Dairy biomass (DB) selected in current study has lower FC and hence contributes less heat. While most of the past studies deal with gasification of coal, current study concentrates on DB as fuel. Experimental results are presented for gasification of i) dairy biomass (DB) and ii) DB ash blends (DBAB) using a 10 KW fixed bed counter-flow gasifier and air-steam as oxidizing source. The results show that the reactor operates almost adiabatically. The effects of the Φ and S:F ratio on peak temperatures, gas composition, gross heating value of the products (HHV), and energy conversion efficiency (ECE) are investigated. A mass spectrometer has been used to analyze the composition of gases in real time continuously. Increasing Φ or S:F increases the production of H2 and CO2 but decreases the production of CO; thus, the reaction of CO+H2O→CO2+H2 seems to control the composition of gases. The operating parameters include 1.59<Φ<6.36 and 0.36<S:F<0.8. Energy Conversion efficiencies (ECE) range from 0.26 to 0.80.

scholarly journals Progress in Material Development for Low-Temperature Solid Oxide Fuel Cells: A Review

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1280
Author(s):  
Mohsen Fallah Vostakola ◽  
Bahman Amini Horri
Keyword(s):  
Fuel Cells ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Energy Conversion ◽  
Operating Temperature ◽  
Energy Conversion Efficiency ◽  
Solid Oxide ◽  
Ohmic Loss ◽  
Oxide Fuel ◽  
The Impact

Solid oxide fuel cells (SOFCs) have been considered as promising candidates to tackle the need for sustainable and efficient energy conversion devices. However, the current operating temperature of SOFCs poses critical challenges relating to the costs of fabrication and materials selection. To overcome these issues, many attempts have been made by the SOFC research and manufacturing communities for lowering the operating temperature to intermediate ranges (600–800 °C) and even lower temperatures (below 600 °C). Despite the interesting success and technical advantages obtained with the low-temperature SOFC, on the other hand, the cell operation at low temperature could noticeably increase the electrolyte ohmic loss and the polarization losses of the electrode that cause a decrease in the overall cell performance and energy conversion efficiency. In addition, the electrolyte ionic conductivity exponentially decreases with a decrease in operating temperature based on the Arrhenius conduction equation for semiconductors. To address these challenges, a variety of materials and fabrication methods have been developed in the past few years which are the subject of this critical review. Therefore, this paper focuses on the recent advances in the development of new low-temperature SOFCs materials, especially low-temperature electrolytes and electrodes with improved electrochemical properties, as well as summarizing the matching current collectors and sealants for the low-temperature region. Different strategies for improving the cell efficiency, the impact of operating variables on the performance of SOFCs, and the available choice of stack designs, as well as the costing factors, operational limits, and performance prospects, have been briefly summarized in this work.

Interface engineering: Boosting the energy conversion efficiencies for nanostructured solar cells

2012 ◽  
Vol 84 (12) ◽  
pp. 2653-2675 ◽  
Author(s):  
Guodong Liu ◽  
Shulin Ji ◽  
Guoping Xu ◽  
Changhui Ye
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Energy Conversion ◽  
Low Cost ◽  
Energy Conversion Efficiency ◽  
Interfacial Structure ◽  
Interface Engineering ◽  
The Status ◽  
Conversion Efficiencies ◽  
Density Of Interface States

Nanostructured solar cells have attracted increasing attention in recent years because their low cost and ease of preparation offer unique advantages and opportunities unavailable with conventional single-crystalline solar cells. The efficiencies of this kind of solar cell largely depend on the interfacial structure owing to the large specific interface areas and the inherent high density of interface states. In this review article, strategies of interface engineering will be introduced in detail. The up-to-date progress and understanding of interface engineering and its role in influencing the efficiency of nanostructured solar cells will be discussed. Some of the representative examples of the interface engineering method will be presented wherever necessary. Continued boosting of the energy conversion efficiency for nanostructured solar cells is anticipated in the coming years and will bring this kind of solar cell to the status of commercialization.

“A Three Solar Cell Mechanically-stacked, Multijunction System with Energy Conversion Efficiencies Greater than 30% Amo”

1987 ◽  
Author(s):  
Allen M. Barnett ◽  
Terry M. Trumble ◽  
Gerald H. Negley ◽  
Sandra L. Rhoads ◽  
James B. McNeely ◽  
...  
Keyword(s):  
Solar Cell ◽  
Energy Conversion ◽  
Conversion Efficiencies

Current progress and performance improvement of Pt/C catalysts for fuel cells

2020 ◽  
Vol 8 (46) ◽  
pp. 24284-24306
Author(s):  
Xuefeng Ren ◽  
Yiran Wang ◽  
Anmin Liu ◽  
Zhihong Zhang ◽  
Qianyuan Lv ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Conversion ◽  
Performance Improvement ◽  
Electric Energy ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Carnot Cycle ◽  
High Energy Conversion Efficiency ◽  
And Performance

Fuel cell is an electrochemical device, which can directly convert the chemical energy of fuel into electric energy, without heat process, not limited by Carnot cycle, high energy conversion efficiency, no noise and pollution.

Sign in / Sign up

Export Citation Format

Share Document