• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.86-94
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• 2017

In Korea, chemical analysis of animal feed is done through authorized feed analysis laboratories (AFALs). Analysis results among the AFALs need to be similar or within acceptable variations; however, there is no experimental evidence of their comparability. We aimed to determine the level of variation of feed chemical analysis results from different AFALs. For this, we requested analysis of four kinds of feed (corn, soybean meal, corn gluten feed, and ryegrass) to eight AFALs and the Cumberland Valley Analytical Services (CVAS) which is an internationally well-recognized feed analysis laboratory. The AFALs spent more time on analysis than did CVAS. Fiber analysis results varied significantly among laboratories. However, moisture, CP, and ash content values showed almost no variation. At least one AFAL obtained results with significant differences from CVAS for all tested values. These differences can be explained by the followings: 1) the standard methods for feed analysis (SMFA) established for AFALs are not detailed enough to control the analytical variations among different laboratories and 2) guidelines are insufficient for the quality control of analysis results in Korea. Failure to accurately identify the nutritional components of the feed could mean failure to provide adequate nutrients to the animals. Therefore, efforts to reduce the differences among AFALs, such as revising SMFA and publishing guidelines on quality control of feed analysis results, are important.

• Applied Biological Chemistry
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• v.27
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• pp.18-28
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• 1984

In order to improve feed values of Korean agricultural by-products, various treatments including physical, chemical, physicochemical and fermentation were suggested in th is review article. Physical treatments such as chopping, grinding and pelleting reduce partiole size of agricultural by-products, and increase passage rate from the rumen, thus may increase voluntary feed intake and weight gain. Digestibility and voluntary feed intake of straw, rice hull and sawdust, also, may be increased by chemical treatment using sodium hydroxide or ammonia. Especially, because nitrogen content of by-products increase and toxic problem is not posed by ammonia treatment, it's practical usage is recommended in Korea. Silage or fermentation treatment using principles of microbial fermentation may improve palatability of low quality by-products. As mentioned above, it is concluded that various treatments suggested are desirable and improve feed value but may raise several problems. Unfortunately, because cost for installation and products is great and processing work is complicate, farmers are not using well these processing methods until now. Therefore, in order to increase the practical usage at farm level, it is thought that many research works be achieved for efficient process which have simple operation and low installation cost.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.729-737
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• 2009

This paper introduces the machine tools feed system, which can be optimized the control's performance through simulation and the adjustment of the mechanical components. One method simulates the frequency response of the speed-loop with the design value using the MATLAB application, so that all of the interpolation axis can be equal to the response bandwidth, resulting in a high accuracy rate. The other method sees the mechanical component being adjusted by analyzing the results of various experiments. Lastly, this client's program is able to change the parameters that are related to the FFD, as well as the parameters in the friction compensation of the OPEN-CNC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.859-867
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• 2000

In order to analyze the effect of a cover layer or radome for an antenna, the moment method is applied to the analysis of the circular microstrip patch antenna with dielectric superstrate fed by coaxial probe. The probe feed is modeled as a attachment mode method which can solve more exact analysis. In case of a ideal probe feed modeling, the probe self-impedance as well as the rapidly-varying patch current at the vicinity of the feed point was neglected. But a rigorous probe feed model which overcomes these deficiencies are developed, and used in the analysis of isolated circular patches. Measurements were performed to validate the numerical results. These are good agreement with each other.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.888-897
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• 2009

Lipase diversity in glacier soil was assessed by culture-independent metagenomic DNA fragment screening and confirmed by cell culture experiments. A set of degenerate PCR primers specific for lipases of the hormone-sensitive lipase family was designed based on conserved motifs and used to directly PCR amplify metagenomic DNA from glacier soil. These products were used to construct a lipase fragment clone library. Among the 300 clones sequenced for the analysis, 201 clones encoding partiallipases shared 51-82% identity to known lipases in GenBank. Based on a phylogenetic analysis, five divergent clusters were established, one of which may represent a previously unidentified lipase subfamily. In the culture study, 11 lipase-producing bacteria were selectively isolated and characterized by 16S rDNA sequences. Using the above-mentioned degenerate primers, seven lipase gene fragments were cloned, but not all of them could be accounted for by the clones in the library. Two full-length lipase genes obtained by TAIL-PCR were expressed in Pichia pastoris and characterized. Both were authentic lipases with optimum temperatures of ${\le}40^{\circ}C$. Our study indicates the abundant lipase diversity in glacier soil as well as the feasibility of sequence-based screening in discovering new lipase genes from complex environmental samples.

• Korean Journal of Poultry Science
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• v.39 no.1
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• pp.33-37
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• 2012

One of the biggest challenges for the animal feed industry in the coming years will be to meet the growing demand in animal protein in light of increased cost of feed ingredient as well as tougher restrictions on the use of antimicrobial growth promoters imposed by consumers and governments. A key focus area will be to maximise feed efficiency and minimise nutrient waste. It has been widely acknowledged that the composition of the intestinal microflora is closely related to intestinal health and performance of animals. Advanced microbial techniques have shown a close relationship between bacterial communities and their ability to modulate nutrient absorption and processing. In addition it has been recognised that modulating the immune response has significant impact on overall health as well as overall nutrient demand. Molecular techniques are a useful tool to gain an understanding of the impact of dietary interventions including the use of functional feed additives on specific changes in microbial communities or the immune system. Most these techniques however focus on the evaluation of large changes in bacterial compositions and often underestimate or neglect to recognise small changes in microbial diversity or behaviour changes without any measurable immune response. The key to understanding the relationship between specific nutritional intervention and the impact on health and performance lies in a deeper understanding of the impact of these nutrients on the expression of specific genes or specific metabolic pathways. The development of molecular tools as a result of developments in the field of Nutrigenomics has enabled researchers to study the effects of specific nutrients on the whole genome or in other words, the effect of thousands of genes simultaneously, and has opened a completely different avenue for nutritional research.

• Korean Journal of Construction Engineering and Management
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• v.16 no.5
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• pp.65-76
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• 2015

FEED (Front End Engineering and Design) is the key area that determines the competitiveness of procurement and construction in the EPC contracts especially in terms of the added value. Nevertheless, previous researches in FEED have been limited to the process and deliverable of design work or the particular management business function (e.g. System Engineering, collaboration, information etc.). In this context, the purpose of this study is to propose a comprehensive FEED structure and its functions from the project management perspective throughout the whole project life-cycle for thermal power plants. Proposed FEED business procedures are classified into three levels; First level is the classification of FEED business phases, the second level defines major FEED management functions, and the third level is detailed FEED functions. A survey using proposed FEED functions and assessment variable was conducted in order to analyze the current status and the areas for future improvement. It is expected that the proposed structure, functions, and evaluation methodology for FEED management will contribute to effective practice of FEED as well as to improvement of competitive capability for engineering, procurement, and construction (EPC) companies.

• The Journal of the Acoustical Society of Korea
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• v.23 no.4
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• pp.303-308
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• 2004

In this Paper a transmitter system for IMr-2000 using feed-forward linearization method was Proposed to linearize power amplifier. The feed-forward structure needs a reference signal to compare and neutralize distortion : this is achieved through the second modulator which is operated at very low input level to obtain a signal with a negligible distortion. Therefore, this structure can reduce distortion of modulator as well as Power amplifier. This is the advantage over the existing system structure. The Proposed transmitter system is designed and simulated by Agilent ADS ver.2002. A two tone test for the system is done at 1.98GHz center frequency with frequency spacing of 2MHz. The reduction of Inter-Modulation Distortion(IMD) is around 49.95dB. This proposed system offers an excellent combination of linearity and simplicity.

• Membrane and Water Treatment
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• v.2 no.3
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• pp.159-173
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• 2011

The air gap membrane distillation (AGMD) process was applied for water desalination. The main objective of the present work was to study the heat and mass transfer mechanism of the process. The experiments were performed on a flat sheet module using aqueous NaCl solutions as a feed. The membrane employed was hydrophobic PTFE of pore size 0.22 ${\mu}m$. A mathematical model is proposed to evaluate the membrane mass transfer coefficient, thermal boundary layers' heat transfer coefficients, membrane / liquid interface temperatures and the temperature polarization coefficients. The mass transfer model was validated by the experimentally and fitted well with the combined Knudsen and molecular diffusion mechanism. The mass transfer coefficient increased with an increase in feed bulk temperature. The experimental parameters such as, feed temperature, 313 to 333 K, feed velocity, 0.8 to 1.8 m/s (turbulent flow region) were analyzed. The permeation fluxes increased with feed temperature and velocity. The effect of feed bulk temperature on the boundary layers' heat transfer coefficients was shown and fairly discussed. The temperature polarization coefficient increased with feed velocity and decreased with temperature. The values obtained were 0.56 to 0.82, indicating the effective heat transfer of the system. The fouling was observed during the 90 h experimental run in the application of natural ground water and seawater. The time dependent fouling resistance can be added in the total transport resistance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2028-2038
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• 2003

High-speed feed drive systems have been widely used in the manufacturing and semiconductor industries. Specifications for high-speed systems require more advanced capabilities than conventional feed drive systems. It is necessary to devise special design concepts to achieve the level of performance for high-speed feed drive systems. In this paper, an integrated design method is proposed for high-speed feed drive systems in which the interactions between mechanical and electrical subsystems ought to be considered simultaneously during the design process. Based on the integrated design method, a nonlinear optimal design procedure of mechanical subsystems considering the Abbe and radius errors is accomplished through the design process of electrical subsystems satisfying the control stability and the saturation condition of actuators as well as the relative stability. Both mechanical and electrical parameters are considered as design variables. Simulations and numerical case studies show that the integrated design method of high-speed feed drive systems creates results satisfying the desired performances of mechatronic systems.