• Resources Recycling
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• v.30 no.1
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• pp.3-13
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• 2021

In the secondary refining process for the production of high-grade steel, the proper composition is maintained by alloying elements, and non-metallic inclusions are controlled for high cleanliness. Complex reactions occur simultaneously between the molten steel, slag, inclusions, refractories, and alloying elements during the secondary refining process. Previous works have reported simulation models based on kinetics to predict the compositional changes in molten steel, slag, and inclusions in actual processes. Analytical reviews are required for the models to predict the process accurately. In this study, we reviewed and analyzed simulation models based on the coupled reaction model for the secondary refining process.

• International Journal of Knowledge Content Development & Technology
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• v.11 no.2
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• pp.7-21
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• 2021

The study was a descriptive cross-sectional survey which investigated the reading preferences of secondary school students in Nigeria during the lockdown occasioned by COVID-19 pandemic. A hundred secondary school students in Ile- Ife and Ilesa in Osun State, Nigeria were the study respondents. Close ended self-administered questionnaire was used to obtain data. Of the one hundred questionnaire which were applied to the study respondents, ninety-three were retrieved. Data obtained were analyzed using simple frequencies and percentages. The study established that majority of respondents were not pressured to read but read for pleasure. Preference for a wide range of fiction and non-fiction books which was read for purposes ranging from academic, social, relaxation and information was indicated by respondents. Availability of reading materials determined reading preference of majority of respondents as many could not afford to access electronic books whether free or not. The researchers recommended that different types of reading materials that suit the reading preferences and meet the diverse purpose of reading should be provided for the secondary school students during lockdown to improve their reading habits. Public libraries should function during this lock down period within the guidelines of the appropriate health authorities, while school libraries should be equipped to offer virtual services during the lockdown and the students should be exposed to e-books for their reading pleasure.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.297-302
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• 2003

The effects of risering design and alloying element on the formation of defects such as external depression, primary and secondary shrinkage cavity in gray cast iron were investigated. Two types of risering design for the cylindrically step-wise specimen, No. 1(progressive solidification) and No. 2(directional solidification) risering designs, were prepared and five different alloy compositions were casted. In the No. 1 risering design, external depression or primary shrinkage cavity due to liquid contraction was observed in all the specimens from ISO 150 to ISO 350. The primary shrinkage cavity was located right under the top surface or connected to the top surface, and was characterized by smooth surface. Its size increased with an increase in ISO number. However, neither secondary shrinkage cavity nor swollen surface was observed in all the castings. In the No.2 risering design, neither primary shrinkage cavity nor secondary shrinkage cavity was observed in all the specimens due to proper risering design. A swollen surface was also not observed in all the castings with the application of pep-set mold.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.252-256
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• 2001

The rapid development of communication equipment and information processing technology has led to a constant improvement in cordless communication. Lithium ion batteries used in cellular phones and laptop computers, in particular, have been in the forefront of the above revolution. These batteries use high value added raw materials and have a high and stable energy output and are increasingly coming into common use. The development of the material for the negative terminal has led to an improvement in the quality and efficiency of the batteries, whereas a reduction in the cost of the battery by researching new materials for the positive anode has become a research theme by itself. These long life batteries, it is being increasingly realized, can have value added to them by recycling. Research is increasingly being done on recycling the aluminum case and the load casing for the negative diode. This paper aims to introduce the current situation of recycling of lithium ion batteries. 1. Introduction 2. Various types of batteries and the situation of their recycling and the facts regarding recycling. 3. Example of cobalt recycling from waste Lithium ion secondary cell. 3-1) Flow Chart of Lithium ion battery recycling 3-2) Materials that make a lithium ion secondary cell. 3-3) Coarse grinding of Lithium ion secondary cell, and stabilization of current discharge 3-4) Burning 3-5) Grinding 3-6) Magnetic Separation 3-7) Dry sieving 3-8) Dry Classifying 3-9) Content Ratio of recycled cobalt parts 3-10) Summary of the Line used for the recovery of Cobalt from waste Lithium ion battery. 4. Conclusion.

• Hwankyungkyoyuk
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• v.19 no.3
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• pp.165-182
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• 2006

Demands for developing diverse teaching methods and materials which can lead to active participation of students in classes have been emerged for environmental education in secondary schools. In order for more effective environmental education, a variety of programs in the mass media including public broadcasting have been used. Advantages associated with the broadcasted TV programs include compensation of temporal and spatial limits embedded with the printing media, improvement of studying efficiency, and provision of diverse studying opportunities, leading to the promotion of the awareness of environmental issues. In this study, 256 environmental issues related TV programs being aired via major public broadcasting companies such as EBS, KBS, MBC and SBS between years of 2003 and 2004 were analyzed. During the present research, selection of the programs was made based on the weight of the environmental issues in independent programs being aired for at least 10 minutes. A survey as a primary means was carried out for the utilization of the audio-visual educational materials in order to provide a new method employing the TV programs which were related to the environmental issues during the instruction in secondary schools.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.169-172
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• 2009

We developed ultra-accelerated quantum chemical molecular dynamics and characterization simulators for study and design of plasma display panel (PDP) related materials. By use of these simulators, realistic structure of PDP materials is drawn on the computer. Furthermore, based on the structures, various properties such as secondary electron emission coefficient are successfully evaluated. In this report, we will discuss the theoretical secondary electron emission coefficient for several protecting layer materials and the effect of surface structure on the properties based on the result of atomistic simulations.

• Journal of Powder Materials
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• v.29 no.3
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• pp.252-261
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• 2022

Cobalt is a vital metal in the modern society because of its applications in lithium-ion batteries, super alloys, hard metals, and catalysts. Further, cobalt is a representative rare metal and is the 30th most abundant element in the Earth's crust. This study reviews the current status of cobalt extraction and recycling processes, along with the trends in its production amount and use. Although cobalt occurs in a wide range of minerals, such as oxides and sulfides of copper and nickel ores, the amounts of cobalt in the minerals are too low to be extracted economically. The Democratic Republic of Congo (DRC) leads cobalt mining, and accounts for 68.9 % of the global cobalt reserves (142,000 tons in 2020). Cobalt is mainly extracted from copper-cobalt and nickel-cobalt concentrates and is occasionally extracted directly from the ore itself by hydro-, pyro-, and electro-metallurgical processes. These smelting methods are essential for developing new recycling processes to extract cobalt from secondary resources. Cobalt is mainly recycled from lithium-ion batteries, spent catalysts, and cobalt alloys. The recycling methods for cobalt also depend on the type of secondary cobalt resource. Major recycling methods from secondary resources are applied in pyro- and hydrometallurgical processes.

• Journal of Nutrition and Health
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• v.11 no.1
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• pp.17-20
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• 1978

The materials carcinogenic agent, nitrosoamine, is distributed in food circumstances, and is formed when both nitrite and secondary amine are present. Nitrites are added to fishes as a color fixative or preservative and secondary amines exist in fishes. In order to find the distribution and contents of secondary amines, analysis of 19 kinds of fish was conducted. The results showed that, significant differences were not observed in the quantity of secondary amines in 19 kinds of fish by district. The highest value was 20.29 ppm in Theragra chalocogramma and the lowest was 0.022 ppm in Ostrea denselamellosa. Six fishes below 1 ppm were Nibea imbricata, Misgurnus mizolepis, Astroconger myriaster, Evynnis Japonica, Ostrea denselamellosa and Solen gouldi. Dimethyl amine only was identified and diethylamine or diphenylamine was not detected in all kinds of 19 fishes.

• Corrosion Science and Technology
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• v.15 no.2
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• pp.54-57
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• 2016

Magnesium alloys have been extensively studied in recent years for potential biodegradable implant applications. A great deal of work has been done on the evaluation of the corrosion behaviour of magnesium alloys under in vitro and in vivo conditions. However, magnesium alloys, in general, contain secondary phase particles distributed in the matrix and/or along the grain boundaries. Owing to their difference in chemistry in comparison with magnesium matrix, these particles may exhibit different corrosion behaviour. It is essential to understand the corrosion behaviour of secondary phase particles in magnesium alloys in physiological conditions for implant applications. This paper critically reviews the biodegradation behaviour of secondary phase particles in magnesium alloys.

• Carbon letters
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• v.8 no.4
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• pp.285-291
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• 2007

Carbon materials of various morphologies were synthesized by pyrolysis of Soap-nut seeds (Sapindus mukorossi), Jack Fruit seeds (Artocarpus heterophyllus), Date-seeds (Phoenix dactylifera), Neem seeds (Azadirachta indica), Tea leaves (Ehretia microphylla), Bamboo stem (Bambusa bambus) and Coconut fiber (Cocos nucifera), without using any catalyst. Carbon materials thus formed were characterized by SEM XRD and Raman. Carbon thus synthesized varied in size (in ${\mu}m$) but all showed highly porous morphology. These carbon materials were utilized as the anode in Lithium secondary battery. Amongst the various precursors, carbon fibers obtained from Soap-nut seeds (Sapindus mukorossi) and Bamboo stem (Bambusa bambus), even after $100^{th}$ cycles, showed the highest capacity of 130.29 mAh/g and 92.74 mAh/g respectively. Morphology, surface areas and porosity of carbon materials obtained from these precursors were analyzed to provide interpretation for their capacity to intercalate lithium. From the Raman studies it is concluded that graphitic nature of carbon materials assist in the intercalation of lithium. Size of cavity (or pore size of channels type structure) present in carbon materials were found to facilitate the intercalation of lithium.