• Food Science of Animal Resources
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• v.40 no.4
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• pp.527-540
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• 2020

Donkey in China is well known for its draft purpose and transportation; however, donkey meat has attracted more and more consumers in recent years, yet it lacks sufficient information on its flavor components compared to other main meats. Therefore, in this study, volatile flavor compounds in neck meat of donkey, swine, bovine, and sheep were classified by electronic nose, then confirmed and quantified by gas chromatography-mass spectrometry. High-performance liquid chromatography (HPLC) and gas chromatography were used to quantify free fatty acid, amino acid, and flavor nucleotide. A total of 73 volatile compounds were identified, and aldehydes were identified as the characteristic flavor compounds in neck meat of donkey, bovine, swine and sheep in proportion of 76.39%, 46.62%, 31.64%, and 35.83%, respectively. Particularly, hexanal was the most abundant volatile flavor. Compared with other neck meat, much higher unsaturated free fatty acids were present in donkeys. Furthermore, neck meat of donkeys showed essential amino acid with highest content. Thus, special flavor and nutrition in donkey neck meat make it probably a candidate for consumers in other regions besides Asia.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.5
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• pp.29-40
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• 2009

Pneumatic system is widely applied to ground facility and launcher on-board system. One of the important aspects of pneumatic system is to meet pressure and flow rate requirements of gas consumers. In this paper, a systematic analytical approach for pneumatic system is proposed, which uses and systematically combines previous studies. The proposed analytical method is that pressure/flow calculation using conservation equations are combined with sonic limit check at vena contracta of the components of pneumatic system, which checks the installed components whether they are merely pressure loss elements or flow limiting element of the system. In this paper, gas consumers are categorized and simulated using the proposed method. The results reveal that the feeding performance of general pneumatic system can be properly estimated using the proposed approach.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.57-61
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• 2017

The vehicle label fuel economy is used as an energy management indicator nationwide. It induces technology development of automobile manufacturers and plays a role of providing information when purchasing a consumer vehicle. However, consumers who purchase a new vehicle continued to complain that the label fuel economy is different from the mandatory fuel economy rate. The domestic fuel economy measurement method is the same as the North American measurement method. The results of the two test modes (urban (FTP-75 mode), highway (HWFET mode)) are calculated in five test modes reflecting various environmental conditions and driving patterns 5-cycle correction formula is used which is equivalent to the fuel efficiency value. In this study, to solve the consumers' curiosity about the fuel economy of new vehicle, we use domestic fuel economy measurement method to measure the new car condition within 150 km of driving distance and the cumulative driving distance condition of domestic label fuel economy test vehicle. A comparative evaluation of fuel economy was carried out for a durability vehicle of $6,500{\pm}1,000km$. A result, mean value of the fuel economy of the four gasoline vehicles increased by 2.7 % in the city center mode and by 2.5 % in the highway mode in the durable vehicle compared new vehicle. And in the case of the diesel vehicle it increased by 2.5 % and 3.9 % respectively. The harmful exhaust gas emitted from the vehicle also resulted in more emissions of both gasoline and diesel vehicles in new vehicles. It is considered that the increase of the frictional force of the vehicle driving system and the lubricating oil system would have an effect on the reduction of the fuel economy of the new vehicle, and it was found that the fuel economy and the exhaust gas were improved by proper cumulative distance (domesticate) to the new vehicle.

• Environmental and Resource Economics Review
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• v.32 no.3
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• pp.191-215
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• 2023

This study focuses on evaluating and comparing residents' acceptance of unutilized heat such as hydrothermal energy and waste heat from waste incineration and data centers in the case that they are used as district heat sources. This is because securing residents' acceptance is significantly important in order for unutilized heat to be considered as a heat source of district heating and cooling to achieve neutrality in the heating and cooling sector. A survey of heating consumers' perception on unutilized heat energy is conducted and a conjoint model is used to analyze the willingness to pay of heating consumers on incineration heat, water heat, and data center waste heat and to compare them with existing gas heat sources. As a result of the analysis, it is confirmed that district heating using hydrothermal energy and data center waste heat is preferred to district heating from heat from a natural gas plant or waste incineration.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.318-329
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• 2011

This study focuses on enhancing the accuracy of consumption function of Korean natural gas for city gas. It is using time-series model with time-varying coefficients taking into account the recent abnormal temperature phenomenon and the changing gross domestic product (GDP) as important variables. This study estimates the cointegrating regression model for the long-run estimation and the error correction model for the short-run estimation. The consumption function of Korean natural gas is estimated to be influenced by the time-varying coefficients of GDP and temperature. Using the estimated time-series model with time-varying coefficients, this study forecasts the consumption of natural gas for city gas from July 2011 to December 2012. The consumption in 2011 would be 18,303 thousand tons, which is little different from the imported 18,681 thousand tons. The consumption of natural gas for city gas in 2012 is forecast to be 19,213 thousand tons. The consumption model of this study is needed to extend by considering the relative prices between natural gas and its substitutes, the scale of consumers and others.

• Analyses & Alternatives
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• v.5 no.2
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• pp.77-105
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• 2021

Natural gas consumption in Asia is growing at fast tempo because of various factors such as economic growth in the region, urbanization, coal-to-gas switch at power and industry sector. Due to geographical characteristics and lack of international pipeline connections between countries in the continent, majority of natural gas exported to Asian consumers is transported by tankers on the sea in the form of liquefied natural gas. As Asian market is the most lucrative market with the fastest demand growth, the competitions between LNG sellers for market share in Asian market are strengthening. The competitions accelerated, especially after the introduction of large volume of incremental supply into the market by new exporters from the U.S., Australia, and Russia. Cheniere Energy, the first exporter of liquefied natural gas (LNG) in the lower 48 states of U.S. has not adopted the traditional price formation mechanism and business model. Traditionally, prices of long-term LNG contracts have been indexed to the price of competing fuels, such as crude oil. The company adopted a pricing mechanism and business model based on a cost-plus system. Cheniere Energy opted for the safer and the risk-free pricing system, that annually guarantees a fixed amount of revenue to the seller. The company earns the same amount of money, regardless of natural gas price dynamics in the domestic and international market, but possibly with less revenue. However, by introducing and successfully implementing the safer and risk- free business model, Cheniere Energy, a company of a relatively smaller size in comparison with major oil and gas companies, became an example to other smaller-sized companies in the U.S. The company's business model demonstrated how to enter and operate LNG business amid increasing competitions among sellers in the U.S. and international market.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.728-729
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• 2015

As environmental issues have been increased globally, eco-friendliness in the construction area, which accounts for more than 30% of total GHG gas emission has being urged. In response, the Korean government has implemented G-SEED(Green Standard for Energy and Environmental Design) certification from 2002. However, total number of certified apartment buildings is only around 1% of total number of approved apartment buildings. As a basic research to find out reasons of low rate of the certification, this paper analyzes consumers' decision-making process in G-SEED certified apartment building market comparing to non G-SEED certified one and draw System Dynamics modeling based on causal relationship. As a result, consumers' demand for the certified one is increased by 'Perceived Relative Utility' which is resulted from comparison process with non-certified one. The 'Perceived Relative Utility' is ascended upward steadily by 'Relative Perceived Price' considered as relatively short-term effect and 'Favorable Image of Certified Housing' referred to long-term effect.

• Korean Institute of Interior Design Journal
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• no.15
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• pp.86-93
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• 1998

An Apartment Veranda is a transitive space which is being used for many different purpose. A Rear Veranda which is connected to the kitchen is an important space for the housekeeping work and it should be planned carefully to reflect the rational and functional designs. Therefore the objective of this research is to suggest a systematic basis for the practical space planning of the Rear veranda that meets the varied needs of consumers by examining its usage pattern through the analysis of the apartment occupant's behavior pattern stored item the degree of satisfaction and consumer requirements. The research was conducted mainly on apartments built after 1990. The following are the conclusions from the research : 1. Most of the research respondents were aware of the absolute need for the Rear veranda. But they expressed dissatisfaction with the space usage. This indicates that the Rear Veranda planning does not reflect the functionality of the space and concentrates on the idea of providing consumers a service space based on the size of the apartment instead. 2. Although the Rear veranda is used as the multipurpose housework space it is mainly used as the laundry and storage space. This shows a big deviation from the concept of the utility space. Because the behavior pattern associated with the Rear Veranda is largely influenced by the traditional life pattern the development of the Rear Veranda as an exclusive space for the housekeeping work. 3. According to a high frequency of the storage of the laundry related item in the Rear Veranda indicated by the research the Rear veranda is used as the laundry room as well as a auxiliary storage space by most people. The installation of gas range is expected to increase due to the expansion of the usage function of the Rear Veranda space. The installation of a specialized refrigerator to store the traditional food is demanded. 4. Consumers need more efficient and functional storage device because the temporary shelves are often being used as the storage device. The perception of the storage device is assumed to have been influence by the traditional life style.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.47-53
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• 2022

Recently, intelligent packaging of foods has been increasingly developed in response to the growing interest of consumers in checking food quality. Indicators, an important element in intelligent packaging, change color to detect specific substances or indicate food quality changes. Gas indicators can be built into food packaging to detect volatile substances that are released when food quality changes. Ethylene gas is produced as climacteric fruits ripen. Climacteric fruit ripening results from a rapid increase in ethylene production and respiration. In the case of packaged fruits, the ethylene gas concentration in the headspace is closely related to the ripeness of each fruit variety. If an ethylene gas indicator that can be used in fruit packaging is available, the consumer will be able to eat the fruit at the optimal time. In this paper, the characteristics and pros and cons of the ethylene gas indicators developed so far were analyzed by reviewing various types of indicators such as metal reduction-based indicator, fluorescence-based indicator, pH indicator-based indicator, and liposome-based indicator.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.110-115
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• 2016

The need for high-strength galvanized steel has recently increased because of the increased number of car consumers who want improved efficiency and exterior quality. High-strength galvanized steel with high corrosion resistance improves the durability of products and exterior quality. Furthermore, the gilt of zinc does not come off during machining because of the fine adhesive property of zinc. When these are welded, zinc has a lower melting temperature than iron, so zinc is more quickly vaporized than iron. Vaporized zinc can stick to electrodes, which increases spatter in welding transportation. Created spatter can enter the molten pool and develop into inner defects or blowholes and pits. Scattered spatter sticks to the product, which leads to the secondary cost of spatter removal. Therefore, in this study, comparisons of amounts of spatter generated are conducted according to the composition of shielding gas in the MIG and CMT processes to find optimal welding parameters.