• Progress in Superconductivity and Cryogenics
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• v.22 no.4
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• pp.45-50
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• 2020

In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.137-142
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• 2005

In this paper, we propose a new servo system design strategy to reduce the position error signal(PES) and track mis-registration(TMR) in magnetic disk drive systems. The proposed method provides a systematic design procedure based on the plant model and an optimal solution via an optimization with a 'Robust Random Neighborhood Search(RRNS)' algorithm. In addition, it guarantees the minimum PES level as well as stability to parametric uncertainties. Furthermore, the proposed method can be used to estimate the performance at the design stage and thus can reduce the cost and time for the design of the next generation product. The reduction of PES as well as robust stability is demonstrated by simulation and experiments.

• Food Science and Preservation
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• v.21 no.4
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• pp.468-472
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• 2014

The effect of pre-storage treatments was investigated to control the occurrence of fruit skin stain in 'Niitaka' pears. The incidence of fruit skin stains was significantly reduced when the fruits were stored in paper bags with a yellow inner color, compared to when they were stored in paper bags with blue and red inner colors. Additionally, the pear fruits that were harvested seven days earlier than their optimum maturity date developed less fruit skin stains in cold storage and retained their quality. Storage in polyethylene (PE) bags did not control the occurrence of fruit skin stains as effectively as did bag-free storage or storage in calcium-coated bags. The dipping of the pear fruits in a chlorine dioxide and calcium solution was highly effective in reducing the fruit skin stains compared to when they were not dipped or when they were dipped only in distilled water. In particular, a 1,500 times diluted solution of sodium dichloroisocyannurate (NaDCC) reduced the incidence of fruit skin stains and the size of the lesions. No stain was observed on the skin of the fruit with a water content lower than 67.7% (w/v) during its storage. In conclusion, packaging pear fruits in bags with an inner calcium coat and dipping them in a chlorine dioxide, calcium, or NaDCC solution can effectively reduce their skin stains during their storage.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.116-122
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• 1990

In order to improve the shelf life of Tofu, the effect of calcium chloride or acetic acid as coagulants were investigated for microbial and physicochemical changes during the storage in different kinds of soaking solution. The soaking water of Tofu prepared from calcium chloride was found to be spoiled after 15-17 hours of storage at $30^{\circ}C$, by reaching the bacteria count to 10million per ml. The shelf life of the Tofu prepared from acetic acid was better than those prepared by calcium chloride. For the effect of soaking solution on storage life, soaking Tofu in 0.1% acetic acid was found to be more effective than soaking in other solutions of 3% NaCl or 0.1% K-sorbate. The optical density of soaking solution of Tofu increased in proportion to spoilage, and in case of soaked Tofu in 3% sodium chloride and 0.1% K-sorbate solution, it greatly increased. Titratable acidity, and amino nitrogen contents in soaking solution increased as spoilage of Tofu progressed, but pH decreased the early period, one or two days, of stored Tofu and then increased.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.2 s.107
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• pp.169-175
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• 2006

Rotating annular disks are widely used in data storage devices such as CDs, DVDs(digital versatile disks), and HDs(hard disks). Higher data transfer rate in data storage disks could not be achieved by polycarbonate disks in the present market. The problem can be solved by applying the fiber-reinforce composite materials to the disks. In this paper, an application of composite materials to rotating disks is proposed to increase the critical speed. Dynamic equation is formulated in order to calculate the natural frequency and critical speed for rotating composite disks by the Galerkin method. The orthogonal functions are used in series solution. A companion paper(Part II) presents and discusses the numerical results of vibration analysis and critical speed for rotating polar orthotropic disk using the formulation and solution method given in this paper (Part I).

• Food Science and Biotechnology
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• v.18 no.2
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• pp.425-431
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• 2009

Antimicrobial coating on chicken carcasses may reduce the effects of cross-contamination and improve product shelf-life and safety. Thyme oil was mixed at 0.5%(v/v) with a pre-gelatinized pea starch coating solution. The coating solution was spread on chicken breast meat after inoculation with selected spoilage and pathogenic bacteria. After inoculation, the chicken meats were packaged in plastic bags and stored at $4^{\circ}C$. During 12 day storage, total aerobic bacteria, lactic acid bacteria, and inoculated organisms were counted at 4 day intervals. Thyme oil treatments reduced the viability of Salmonella as well as the growth of Listeria and Pseudomonas by 2 log CFU/g, and appeared to eliminate inoculated Campylobacter during storage. The addition of thyme oil increased the viscosity of the pre-gelatinized pea starch solution. The results suggested that thyme oil inclusion in an edible starch coating may be a satisfactory delivery system to enhance the safety of processed fresh meat.

• Structural Engineering and Mechanics
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• v.73 no.1
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• pp.83-95
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• 2020

In this work, a mathematical model of beam-column system carrying a double eccentric end mass system is investigated, and solved analytically based on the exact solution analysis. The model considers the case in which the double eccentric end mass is a rigid storage tank containing fluid. Both Timoshenko and Bernoulli-Euler beam bending theories are considered. Equation of motion, general solution and boundary conditions for the present system model are developed and presented in dimensional and non-dimensional format. Several important non-dimensional design parameters are introduced. Symbolic and/or explicit formulae of the frequency and mode shape equations are formulated. To the authors knowledge, the present reduced closed form symbolic and explicit frequency equations have not appeared in literature. For different applications, the results are validated using commercial finite element package, namely ANSYS. The beam-column system investigated in this paper is significant for many engineering applications, especially, in mechanical and structural systems.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2265-2268
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• 2012

Aqueous solution of oxygenated Direct yellow 12 dye has been evaluated spectrophotometrically as a possible gamma rays dosimeter. The neutral (pH-7), alkaline (pH-12.5) and acidic (pH-5.5) aqueous solution of the dye were prepared and exposed to various gamma doses. Absorption spectra of unirradiated and irradiated solutions were recorded at 400 nm peak. The increase in absorbance with the increase in irradiation dose was observed from 1 to 6 kGy. The stability response of the dye solution for different environmental conditions such as temperature (low & high), light and darkness were investigated during post irradiation storage for ten days. The dye solution showed high stability in darkness for the studied period. The optical density of the dye solution was found to be decreased at high temperature storage.

• Earthquakes and Structures
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• v.16 no.1
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• pp.1-9
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• 2019

To provide a simplified method for the base isolation design of LNG tanks, such as $16{\times}104m^3$ LNG tanks, we conducted a derivation and calculation example analysis of the dynamic response of the base isolation of LNG storage tanks, using dynamic response analysis theory with consideration of pile-soil interaction. The ADINA finite element software package was used to conduct the numerical simulation analysis, and compare it with the theoretical solution. The ground-shaking table experiment of LNG tank base isolation was carried out simultaneously. The results show that the pile-soil interaction is not obvious under the condition of base isolation. Comparing base isolation to no isolation, the seismic response clearly decreases, but there is less of an effect on the shaking wave height after adopting pile top isolation support. This indicates that the basic isolation measures cannot control the wave height. A comparison of the shaking table experiment with the finite element solution and the theoretical solution shows that the finite element solution and theoretical solution are feasible. The three experiments are mutually verified.

• Membrane and Water Treatment
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• v.13 no.1
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• pp.39-49
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• 2022

Seawater desalination is doubtlessly a viable option to supply fresh drinking water. Nevertheless, RO (reverse osmosis) desalination plants in specific areas may be intermittently operated to match the imbalance between water demand and supply. Although a handful of works have been done on other membrane systems, few studies have attempted to mitigate fouling in intermittent RO systems. Accordingly, the objectives of this paper were to examine the effect of the intermittent operation on RO fouling; and to compare four intermittent operation modes including feed solution recirculation, membrane storage in the feed solution, deionized water (DI) recirculation, and membrane storage in DI water. Results showed that intermittent operation reduced RO fouling under several conditions. However, the extents of fouling mitigation were different depending on the feed conditions, foulant types, and membrane lay-up methods. When the feed solution was recirculated during the lay-up, the restoration of the flux was less significant than that by the feed solution feed-up. The use of deionized water during the lay-up was effective to restore flux, especially when the feed solution contains scale-forming salts (CaSO₄) and/or colloidal silica.