• Composites Research
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• v.34 no.5
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• pp.269-276
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• 2021

PCM (Prepreg Compression Molding) process is a high-speed molding technology that can manufacture high-quality CFRP (Carbon Fiber Reinforced Plastic) parts. Compared to the autoclave process, it generates less waste and can significantly reduce cycle time, so various studies are being conducted in the aerospace and automobile industries. In this study, in order to improve the quality of the PCM process, a molding method was developed to increase the compression pressure of the press step by step according to the curing behavior of the prepreg. It was confirmed that this multi-stage compression molding technology is a good means to produce high-quality CFRP products and shorten cycle times. And, the laminated prepreg at room temperature was immediately put into the mold and preheated and molded at the same time, so that it could be molded without a separate preheating process. In addition, as a result of applying the same process conditions optimized for flat plate molding to three-dimensional shapes, a product similar to a flat plate in appearance could be made without the process of establishing process conditions.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.789-797
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• 2018

This study investigated the activity of crude enzymes obtained from Pyrus pyrifolia cv. Shingo on milk proteins. In the milk processing industry, there is an increasing interest in the addition of functional materials to dairy products or functional peptides isolated from milk proteins. First, Pyrus pyrifolia cv. Shingo was separated into core, flesh, and peel regions, and crude enzymes were obtained from the individual regions. The activity of the obtained crude enzymes was measured using casein and gelatin agar. The crude enzyme obtained from the flesh of Pyrus pyrifolia cv. Shingo decomposed gelatin, but the activity of the crude enzymes obtained from the peel and core regions was insignificant. On the other hand, the crude enzymes obtained from the flesh and core regions of Pyrus pyrifolia cv. Shingo had a remarkable enzymatic activity in casein agar. However, the activity of the crude enzyme obtained from the peel region was insignificant. In addition, the crude enzymes obtained from the individual regions were mixed with casein to induce reactions, and the degradation patterns were investigated through electrophoresis and high performance liquid chromatography (HPLC). According to the results, the crude enzymes from Pyrus pyrifolia cv. Shingo degraded milk proteins. Thus, the results of this study can be used in studies on functionality. Additionally, it is expected that the use of pear peels and cores in the milk processing industry would greatly contribute to the reduction of food waste.

• Resources Recycling
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• v.27 no.6
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• pp.76-83
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• 2018

This article aims to summarize the scrap recycling status of gold, silver, platinum and palladium from foreign countries by courntires and industries in order to utilize the data for securing the raw materials of the domestic urbanmining industry. The amount of gold from scrap has shown a tendency to decrease in countries other than China, which is attributed to the large imports of scrap containing gold in China. The industry demand for gold is the highest in electronic products, but demand is decreasing. The amount of scrap recycling in silver has declined in other regions compared to those in Europe, indicating that the world's overall scrap recycling volume has declined. Production and demand from scrap of platinum and palladium are mostly for catalysts and have been steadily increasing until now. However, it is expected that the amount of waste catalysts in automobiles will decrease with the increase of electric vehicle use.

• Particle and aerosol research
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• v.15 no.1
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• pp.1-13
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• 2019

Current desulfurization and denitrification technologies have reached a considerable level in terms of reduction efficiency. However, when compared with the simultaneous reduction technology, the individual reduction technologies have issues such as economic disadvantages due to the difficulty to scale-up apparatus, secondary pollution from wastewater/waste during the treatment process, requirement of large facilities for post-treatment, and increased installation costs. Therefore, it is necessary to enable practical application of simultaneous SOx and NOx treatment technologies to remove two or more contaminants in one process. The present study analyzes a technology capable of maintaining simultaneous treatment of SOx and NOx even at low temperatures due to the electrochemically generated strong oxidation of the wet-pulse complex system. This system also reduces unreacted residual gas and secondary products through the wet scrubbing process. It addresses common problems of the existing fuel gas treatment methods such as SDR, SCR, and activated carbon adsorption (i.e., low treatment efficiency, expensive maintenance cost, large installation area, and energy loss). Experiments were performed with varying variables such as pulse voltage, reaction temperature, chemicals and additives ratios, liquid/gas ratio, structure of the aeration cleaning nozzle, and gas inlet concentration. The performance of individual and complex processes using the wet-pulse discharge reaction were analyzed and compared.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.342-348
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• 2018

The present study examined the various strength and deformation performances of molding materials recycled using film packaging wastes to ascertain the their applicability to secondary products in construction industries. The stress-strain relationships of molding materials were measured under compression, tension, and flexure in accordance with the ASTM procedure. The measured mechanical properties of recycled molding materials were comparable to typical ranges observed in low-density polyethylene and/or high-density polyethylene. However, to stabilize the properties of the molding materials, further management systems are required as follows: 1) evaluation of mechanical properties of materials with respect to various mixing proportions of waste ingredients; 2) estimation of the effect of foreign substance and moisture contents on the mechanical properties; and 3) establishment of comprehensive database including various sources such as manufacture process including applied pressure to produce the molding materials, and collection region and time of wastes.

• Geomechanics and Engineering
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• v.19 no.1
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• pp.37-47
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• 2019

The main objective of this study is to evaluate and compare the efficiency of ordinary Portland cement (OPC) in enhancing the unconfined compressive strength of soft soil alone and soft soil mixed with recycled tiles. The recycled tiles have been used to treat soft soil in a previous research by Al-Bared et al. (2019) and the results showed significant improvement, but the improved strength value was for samples treated with low cement content (2%). Hence, OPC is added alone in this research in various proportions and together with the optimum value of recycled tiles in order to investigate the improvement in the strength. The results of the compaction tests of the soft soil treated with recycled tiles and 2, 4, and 6% OPC revealed an increment in the maximum dry density and a decrement in the optimum moisture content. The optimum value of OPC was found to be 6%, at which the strength was the highest for both samples treated with OPC alone and samples treated with OPC and 20% recycled tiles. Under similar curing time, the strength of samples treated with recycled tiles and OPC was higher than the treated soil with the same percentage of OPC alone. The stress-strain curves showed ductile plastic behaviour for the untreated soft clay and brittle behaviour for almost all treated samples with OPC alone and OPC with recycled tiles. The microstructural tests indicated the formation of new cementitious products that were responsible for the improvement of the strength, such as calcium aluminium silicate hydrate. This research promotes recycled tiles as a green stabiliser for soil stabilisation capable of reducing the amount of OPC required for ground improvement. The replacement of OPC with recycled tiles resulted in higher strength compared to the control mix and this achievement may results in reducing both OPC in soil stabilisation and the disposal of recycled tiles into landfills.

• Quality Improvement in Health Care
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• v.25 no.1
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• pp.52-65
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• 2019

Purpose: Outbreaks resulting from medication injections have recently been on the rise in Korea despite various established guidelines. The objective of this study was to assess the degree to which healthcare professionals are aware of safe injection practice guidelines and to account for the adherence to and the deviation from safe injection guidelines formulated by healthcare providers. Methods: In November 2016, a cross-sectional anonymous questionnaire covering general characteristics of injections, patient safety culture, awareness of safe injection practices, and adherence to and barriers to safe injection guidelines was issued to healthcare providers who administer medication injections or manage and supervise these injections (N=550). Multivariate logistic regression analysis via enter method was performed to define the influencing factors of adherence of safe injection practices. Results: On average, respondents adhere to 17 of the 24 guidelines. Multivariate logistic regression found that those who were more likely to adhere to safe injection guidelines either underwent a patient safety training experience within the last year, provided care in a setting characterized by a highly developed patient safety culture, or were employed as physicians or nurses, as opposed to some other type of care provider. Barriers to safe injection guidelines were attributable to; thoughts of waste to discard leftover medicine, provisions that made adherence cumbersome, a weak culture of compliance, and insufficient amounts of injectable medicine, products, and education. Conclusions: The results of this study indicate that controllable factors like training experience of healthcare providers and patient safety culture were positively associated with adherence to safe injection practices. It was suggested that the training of healthcare providers on safe injection practices be a continuous process to promote patient safety. Additionally, there should be an increased focus on developing and implementing policies to improve patient safety culture from a prevention rather than post-management perspective.

• Resources Recycling
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• v.30 no.5
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• pp.17-24
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• 2021

Natural aggregate regular exploitation has led to environmental and resource depletion issues; consequently, construction waste has become an important raw material in the supply of aggregate smoothly. The recycled aggregate produced in the most of recycled aggregate processing company in Korea has a high adhesion ratio of cement paste and mortar, which affects the water absorption ratio and density. Therefore, the quality of recycled aggregate needs to be improved. In this study, we improved the quality of recycled aggregate through the use of a multistage separation ball mill. This ball mill has a sieve which protects the ball mix and improves the motion. Products produced by using multistage separation ball mill were compared with various quality standard for utilization as recycle aggregate. Finally, we confirmed that the multistage separation ball mill can efficiently separate cement paste and mortar from natural aggregate and that it is suitable for the production of recycled aggregates.

• The Journal of Korean Philosophical History
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• no.32
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• pp.251-276
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• 2011

In old days when there were no developed producing devices like today, all the scholars insisted that we should economize products and that will lead to economic stability of a nation. But the in case of Mozi, he criticized the ruler's extravagance and wastefulness. He tried to prove the result and its' effect on national economy and people's usual life. He also tried to protect and improve people's fortunes and productivity through his theories. He is one of the first scholars who thought about the relationship between labor cost, price theory and product circulation. His theories are in the book of Mojing. He thought that material condition makes a great impact on the people's ethical life and social systems. He devoted his life to improve his theory- if the nobility do not waste and exploit; the national economy will be developed. In Mozi's Economical theory, we can find out his love for the people and desire for the people's welfare.

• Journal of the Korean Chemical Society
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• v.66 no.2
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• pp.92-95
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• 2022

Failure Renal is the function of the kidneys to remove waste products and keep them on the periphery. and minerals for the body. Chronic renal failure is a syndrome characterized by a slow, irreversible deterioration of renal function due to the slow destruction of renal parenchyma. Calcium is one of the important minerals that the body contains in the blood and important tissues, and it has an important role in vital processes such as muscle contraction, nerve impulse conduction, the efficiency of heart muscle work, and blood clotting processes. The aim of the study is to study and compare calcium levels in men and women. It includes studying abnormal levels of calcium that cause many diseases, including chronic renal failure, and studying changes associated with renal failure. The method of this study was conducted on patients with chronic renal failure at Murjan Teaching Hospital in Babylon city during the period. The study included a sample of 70 patients (40 males, 30 females) with chronic renal failure, their ages ranged from 30-65, and 60 (30 males, 30 females) healthy without the disease of the same age. The result was a significant decrease in the number of red and white blood cells, hemoglobin concentration, hematocrit and platelets in patients with chronic renal failure, The result has been showed significant level in enzymes activity for transfer of amine group (alanine amino transferase, aspartate amino transferas) and phosphatase alkaline and also concentration of total bilirubin in patient with compare with healthy, Significantly increases, were found in the concentration of urea, uric acid and creatinine, as well as the concentration of calcium and phosphorous ions in the blood serum of patients compared to healthy controls.