• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.5
• /
• pp.305-310
• /
• 2009

The amount of heat loss of a refrigerator through the gasket is nearly 30% of total refrigerator heat loss. In this paper, quantitative evaluation analysis of heat loss through gasket is established with numerical heat transfer analysis. Extending the gasket shape to protect the heat loss from the gasket, power consumption is measured by using real refrigerator in a temperature and humidity chamber and suggest the gasket shape to reduce the heat loss. From the present result of the numerical simulation of heat transfer and experiment with varying gasket shape, we are able to reduce the heat loss about 20-40% by using extended gasket and the power consumption can be reduced about 5%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.5
• /
• pp.473-477
• /
• 2005

A Bi-2223 tape has been developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called 'dynamic resistance' We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external at magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results ana discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.

• ETRI Journal
• /
• v.41 no.5
• /
• pp.637-647
• /
• 2019

Separating highly correlated users can reduce the loss caused by spatial correlation (SC) in multiuser multiple-input multiple-output (MU-MIMO) systems. However, few accurate analyses of the loss caused by SC have been conducted. In this study, we define signal-to-interference-plus-noise ratio (SINR) loss to characterize it in multiuser multiple-input single-output (MU-MISO) systems, and use coefficient of correlation (CoC) to describe the SC between users. A formula is deduced to show the accurate relation between SINR loss and CoC. Based on this relation, we propose a user selection method that utilizes CoC to minimize the average SINR loss of users in massive MU-MISO systems. Simulation results verify the correctness of the relation and show that the proposed user selection method is very effective at reducing the loss caused by SC in massive MU-MISO systems.

• Journal of Korean Society for Quality Management
• /
• v.48 no.4
• /
• pp.535-552
• /
• 2020

Purpose: The main theme of this study is to derive a specific quality loss function with multiple characteristics according to the same analytical structure as the single characteristic quality loss function of Taguchi. In other words, it presents an analytical framework for measuring quality costs that can be controlled in practice. Methods: This study followed the analytical methodology through geometric, linear algebraic, and statistical approaches Results: The function suggested by this study is as follows; $$L(x_1,x_2,{\cdots},x_t)={\sum\limits_{i=1}^{t}}k_i\{x_i+{\sum\limits_{j=1}^{t}}\({\rho}_{ij}{\frac{d_i}{d_j}}\)x_j\}x_i$$ Conclusion: This paper derived the quality loss function with multiple quality characteristics to expand the usefulness of the Taguchi quality loss function. The function derived in this paper would be more meaningful to estimate quality costs under the practical situation and general structure with multiple quality characteristics than the function by linear algebraic approach in response surface analysis.

• Journal of Audiology & Otology
• /
• v.24 no.4
• /
• pp.174-179
• /
• 2020

Background and Objectives: The integration of auditory-visual speech information improves speech perception; however, if the auditory system input is disrupted due to hearing loss, auditory and visual inputs cannot be fully integrated. Additionally, temporal coincidence of auditory and visual input is a significantly important factor in integrating the input of these two senses. Time delayed acoustic pathway caused by the signal passing through digital signal processing. Therefore, this study aimed to investigate the effects of hearing loss and hearing aid digital delay circuit on sound-induced flash illusion. Subjects and Methods: A total of 13 adults with normal hearing, 13 with mild to moderate hearing loss, and 13 with moderate to severe hearing loss were enrolled in this study. Subsequently, the sound-induced flash illusion test was conducted, and the results were analyzed. Results: The results showed that hearing aid digital delay and hearing loss had no detrimental effect on sound-induced flash illusion. Conclusions: Transmission velocity and neural transduction rate of the auditory inputs decreased in patients with hearing loss. Hence, the integrating auditory and visual sensory cannot be combined completely. Although the transmission rate of the auditory sense input was approximately normal when the hearing aid was prescribed. Thus, it can be concluded that the processing delay in the hearing aid circuit is insufficient to disrupt the integration of auditory and visual information.

• Progress in Superconductivity
• /
• v.13 no.2
• /
• pp.111-116
• /
• 2011

Since superconducting wires have no resistance, electromagnets based on the superconducting wires produce no resistive heating with DC current as long as the current does not exceed the critical current of the wire. However, unlike resistive wires, superconducting wires exhibit AC heat loss. Embedding fine superconducting filaments inside copper matrix can reduce this AC loss to an acceptable level and opens the way to AC-capable superconducting coils. Here, we introduce an easy and accurate method to measure AC heat loss from sample superconducting coils by measuring changes in the rate of gas helium outflow from the liquid helium dewar in which the sample coil is placed. This method provides accurate information on total heat loss of a superconducting coil without any size limit, as long as the coil can fit inside the liquid helium dewar. With this method, we have evaluated AC heat loss of two superconducting solenoids, a 180-turn solid NbTi wire with 0.127 mm diameter (NbTi coil) and a 100-turn filamented wire with 1.4 mm diameter where 7 NbTi filaments were embedded in a copper matrix with copper to NbTi ratio of 6.7:1 (NbTi-Cu coil). Both coils were wound on 15 mm-diameter G-10 epoxy tubes. The AC heat losses of the NbTi and NbTi-Cu coils were evaluated as $53{\pm}4.7\;{\mu}W/A^2Hzcm^3$ and $0.67{\pm}0.16\;{\mu}W/A^2Hzcm^3$, respectively.

• Journal of The Korean Astronomical Society
• /
• v.36 no.3
• /
• pp.167-175
• /
• 2003

There is accumulating evidence for a strong link between nuclear starbursts and AGN. Molecular gas in the central regions of galaxies plays a critical role in fueling nuclear starburst activity and feeding central AGN. The dense molecular ISM is accreted to the nuclear regions by stellar bars and galactic interactions. Here we describe recent observational results for the OB star forming regions in M51 and the nuclear star burst in Arp 220 - both of which have approximately the same rate of star formation per unit mass of ISM. We suggest that the maximum efficiency for forming young stars is an Eddington-like limit imposed by the radiation pressure of newly formed stars acting on the interstellar dust. This limit corresponds to approximately 500 $L_{\bigodot} / M_{\bigodot}$ for optically thick regions in which the radiation has been degraded to the NIR. Interestingly, we note that some of the same considerations can be important in AGN where the source of fuel is provided by stellar evolution mass-loss or ISM accretion. Most of the stellar mass-loss occurs from evolving red giant stars and whether their mass-loss can be accreted to a central AGN or not depends on the radiative opacity of the mass-loss material. The latter depends on whether the dust survives or is sublimated (due to radiative heating). This, in turn, is determined by the AGN luminosity and the distance of the mass-loss stars from the AGN. Several AGN phenomena such as the broad emission and absorption lines may arise in this stellar mass-loss material. The same radiation pressure limit to the accretion may arise if the AGN fuel is from the ISM since the ISM dust-to-gas ratio is the same as that of stellar mass-loss.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.5
• /
• pp.1943-1948
• /
• 2014

Purpose: The prevalence of weight loss in esophageal carcinoma patients is high and associated with impairment of physical function, increased psychological distress and low quality of life. It is not known which factors may contribute to weight loss in patients with esophageal carcinoma during radiotherapy in China. The objective of this study was to identify the associated demographic and clinical factors influencing weight loss. Methods: We evaluated 159 esophageal carcinoma patients between August 2010 and August 2013 in a crosssectional, descriptive study. Patient characteristics, tumor and treatment details, psychological status, adverse effects, and dietary intake were evaluated at baseline and during radiotherapy. A multivariate logistic regression analyss was performed to identify the potential factors leading to weight loss. Results: 64 (40.3%) patients had weight loss ${\geq}5%$ during radiotherapy. According to logistic regression analysis, depression, esophagitis, and loss of appetite were adverse factors linked to weight loss. Dietary counseling, early stage disease and total energy intake ${\geq}1441.3$ (kcal/d) were protective factors. Conclusions It was found that dietary counseling, TNM stage, total energy intake, depression, esophagitis, and loss of appetite were the most important factors for weight loss. The results underline the importance of maintaining energy intake and providing dietary advice in EC patients during RT. At the same time, by identifying associated factors, medical staff can provide appropriate medical care to reduce weight loss. Further studies should determine the effect of these factors on weight loss and propose a predictive model.

• Journal of the Korean Society of Physical Medicine
• /
• v.15 no.3
• /
• pp.61-68
• /
• 2020

PURPOSE: The purpose of this study was to investigate the current state of rapid weight loss and physical and mental complaints among elite combat athletes who were selected and trained as national representatives. METHODS: A total of 127 combat athletes who had trained at the national training center in 2019 were enrolled. The questionnaire used as the survey tool was interpreted as words that Korean athletes could easily understand based on the Portuguese version of the 'Rapid Weight Loss Questionnaire' (RWLQ). χ² tests was performed to determine the differences in physical and mental changes according to sports and weight loss method. RESULTS: Combat athletes in Korea regularly undergo rapidly weight loss within a short period of time prior to competition. There were statistically similar results in terms of weight loss method, physical and mental changes and information about weight loss according to the sport. Weight loss methods often limit food and water intake and dehydrate. The physical complaints associated with them are symptoms such as "no energy", "dizziness", and "muscle spasms". The mental complaints include "irritability", "concentration loss" and "anxiety". These symptoms can be caused by side effects such as food intake limitation, water restriction and dehydration. Information sources for weight loss were in the order of "senior or colleagues", "supervisor or coach", and "Internet". No information was obtained from a doctor or dietitian. CONCLUSION: These results provide a baseline for predicting proper weight loss in athletes and provide useful information for developing performance enhancement as well as weight loss.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.30 no.6
• /
• pp.488-496
• /
• 2004

Oral & Maxillofacial surgery can lead to complications that result in abnormal sensation or movement. Inferior alveolar nerve(IAN) injury can result in dysesthesia, paresthsia of the lower lip and chin, so patients presenting with IAN damage suffer from sensory loss. But diagnosis of the nerve injury is largely limited to the subjective statements made by the patient. Distribution of sympathetic nerves parallels the distribution of the somatosensory nerves. Loss of sensory tone causes a concomitant loss of sympathetic activity, resulting in vasodilation of the cutaneous blood vessels that demonstrates greater heat loss. Digital infrared thermographic imaging(DITI) detects infra-red radiation given off by body. DITI can detect minute difference in temperature from different parts of the body and translates the amount of heat into quantitative data. The area of different temperature correlated with pain or disease can be visualized by corresponding color. The objective of this study was to determine the efficacy of DITI in objectively assessing IAN injury. The 19 normal subjects and the 14 patients underwent DITI scan. The normal subjects received unilateral IAN block anesthesia with 2 ml of 2% lidocaine (IAN bolck group) to evaluate temporary alteration in nerve function. Patient group were patients with unilateral IAN damage (dysesthesia or paresthesia) after surgical treatment(Mn. 3rd molar Extraction, etc.). The surgical procedure performed within 6 months of test. The results were as follows. 1. No significant differences in temperature were found between left and right sides of the lower lip and chin in the control group. 2. Significant temperature differences were found between the anesthetized and non-anesthetized sides of the lower lip and chin in the IAN block group. 3. Significant temperature differences were found between the involved and uninvolved sides of the lower lip and chin areas of the experimental group. The results of the study show that DITI can be an useful and effective means of objectively assessing and visualizing IAN damage.