• Advances in Energy Research
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• 제4권1호
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• pp.69-86
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• 2016

The quest to reduce the level of overdependence on fossil fuel product and to provide all required information on proven existing alternatives for renewable energy has resulted into rapid growth of research globally to identify efficient alternative renewable energy sources and the process technologies that are sustainable and environmentally friendly. The present study is aimed at production and characterization of bioethanol produced from sugarcane juice using a $2^4$ factorial design investigating the effect of four parameters (reaction temperature, time, concentration of bacteria used and amount of substrate). The optimum bioethanol yield of 19.3% was achieved at a reaction temperature of $30^{\circ}C$, time of 72 hours, yeast concentration of 2 g and 300 g concentration of substrate (sugarcane juice). The result of statistical analysis of variance shows that the concentration of yeast had the highest effect of 7.325 and % contribution of 82.72% while the substrate concentration had the lowest effect and % contribution of -0.25 and 0.096% respectively. The bioethanol produced was then characterized for some fuel properties such as flash point, specific gravity, cloud point, pour point, sulphur content, acidity, density and kinematic viscosity. The results of bioethanol characterization conform to American society for testing and materials (ASTM) standard. Hence, sugarcane juice is a good and sustainable feedstock for bioethanol production in Nigeria owing relative abundance, cheap source of supply and available land for large scale production.

• KSBB Journal
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• 제23권3호
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• pp.213-218
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• 2008

일반적으로 약주 생산 공정에서 고정화 담체를 이용하는 연속식 반응기에서는 회분식 반응기와 비교하여 생성되는 알코을 생성량 못지않게 연속식 반응기에서 연속적으로 생성되고 있음을 알 수 있었다. 고정화 담체를 이용한 연속식 반응기는 약주의 품질에 긍정적인 효과를 보이는 것으로 나타났으며 담금 공정에서의 처리효과를 분석한 결과는 다음과 같다. 1) 회분식 배양에서 에탄올의 생성량은 1차 담금 1일 째부터 12%이상 증가하는 것으로 나타났으며 연속배양은 2차 담금에 효모를 주입하지 않아도 회분식 배양에서와 같은 알코올 도수를 가지면서 지속적으로 얻어졌다. 또한 pH는 4.4에서 3.8로 감소하는 패턴을 나타냈으며 산소농도는 1 ppm정도 차이가 나타났으나 이는 연속적으로 기질이 반응기로 주입되기 때문에 증가된 것이다. 2) 폴리플로필렌에 폴리스티렌을 샌드위치식으로 접합한 고정화 미생물담체는 연속배양에서 효모 주입 없이도 회분식 배양과 비교해보았을 경우에 당화과정과 알코올 생성과정 등이 서로 상반되는 패턴을 갖으면서 생물학적인 반응이 정상적으로 진행됨을 증명하였다. 3) 연속배양의 실험결론을 토대로 1차 담금에서 당의 생성기질을 이용하였을 경우, 10톤/일 생산하는 약주생산 공장은 1년간 효모 투입비용을 환산해 본 결과 1억원 이상의 투입비용이 감소하는 것으로 나타났다.

• Industrial Engineering and Management Systems
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• 제3권1호
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• pp.52-58
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• 2004

This report examines the issue of designing an efficient production system by increasing several types of flexibility. Increasing manufacturing flexibility is a key strategy for efficiently improving market responsiveness in the face of uncertain market demand for final products. The manufacturing system comprises multiple plants, of which individual plants have multiple manufacturing lines that are designed to produce limited types of products in accordance with their size and materials. Imbalance in the workload occurs among plants as well as among manufacturing lines because of fluctuations in market demand for final products. Thereby, idleness of some manufacturing lines and longer lead times in some manufacturing lines occur as a result of the high workload. We clarify how these types of flexibility affect manufacturing performance by improving only one type of flexibility or by improving multiple types of flexibility simultaneously. The average lead time and the imbalance in workload are adopted as measures of manufacturing performance. Three types of manufacturing flexibility are interrelated: machine flexibility, routing flexibility, and process flexibility. Machine flexibility refers to the various types of operations that a machine can perform without requiring the prohibitive effort of switching from one order to another. Routing flexibility is the capability of processing a given set of part types using more than one line (alternative line) in the plant. Process flexibility results from being able to build different types of final products at the same plant.

• 한국환경보건학회지
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• 제42권6호
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• pp.465-477
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• 2016

Objectives: This review examined the scientific evidence regarding the impact of climate change on food safety. Methods: The impact of climate change on food safety was assessed based on a survey of related publications reported in the past 20 years. The terms used for literature selection reflect three aspects: climate change; food; and food safety. Results: Climate change is expected to affect the key elements of food production - water and climate. These impact on food safety through many different pathways. Directly, food shortages according to the population grovoth result in a food security/food supply problem, These relationships are commonly understood. The indirect impacts include an increase in food-borne diseases and pathogens, increased mycotoxin production, and increased risk of pesticide residues in foods due to greater use of pesticides in response to warming and increased precipitation and the accompanying diseases in certain crops. Field studies and statistical and scenario analyses were performed to provide evidence. However, quantification of these relationships is still lacking. Conclusion: Adaptation measures at the local and community levels are essential since the pressures from weather and climate events may differ according to region and sector. It is recommended that we go beyond empirical observations of the association between climate change and food safety and develop more scientific explanations. We also need to explore alternative materials for bioenergy demands in order to improve sustainability.

• 소성∙가공
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• 제22권5호
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• pp.243-249
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• 2013

The multi-point forming (MPF) process for three-dimensional curved sheet metal has been developed as an alternative to the conventional die forming process since MPF allows the manufacturing of various shapes using one die set and reduce the cost of production. However, the MPF process cannot provide high quality products yet due to defects occurring in the sheet such as dimples and wrinkles. It can also lead to economic loss because of long tool setup time and additional machining required outside of the sheet formed area. In this study, a new sheet metal forming method, called flexible roll forming (FRF), is proposed to solve the problems of existing processes for three-dimensional curved sheet metal. This progressive process utilizes adjusting rods, as well as upper and lower flexible rollers as forming tools. In contrast with the existing processes, FRF can reduce the additional production costs because of the possible blank size for the part longitudinal direction, which is unrestricted. In this research, methods and procedures of the flexible roll forming technology are described. Numerical forming simulations of representative three-dimensional curved sheet products are also carried out to demonstrate the feasibility of this technology.

• 한국실내디자인학회논문집
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• 제13권3호
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• pp.153-161
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• 2004

Organic Modernism was inaugurated by Alvar Valto as an alternative plan to the formative limitation of Geometrical Modernism. It began to appear in the 1930s in the fields of Architecture, Furniture, Product Design and so on. It is known that began with organic formative language is closely related to surrealistic artists Andre Breton as well as other artists and sculptors in that era. Such Formative Language formalized a stream of Organic Modernism Furniture Design unique to the regional and cultural characteristics of Scandinavia. After crossing over to America, mass production of Furniture was born and new materials were linked by industrialization. The Characteristics of Organic Formation in Modern Art such as Three -Dimensional, Biological Morphological, Symbolical, Primitive, Fantastical, Non-Realistic, Incidental, Irregular, transmit to Furniture Design. They are as Characteristics especially with Three-Dimensional, Biological Morphological and Symbolical aspects. Histories of Art and design, there are some examples showing mutual Interchange between Functional and Artistic Character. This thesis also clarifies the Formative Relationship that the Furniture designers who pursued Functionality and Mass Production had obtained from Modern Artistic works and the Artists, through the process of comparing and researching the typical Artists and their works.

• 공업화학
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• 제25권3호
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• pp.337-339
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• 2014

본 연구의 내용은 Dimethyl terephthalate의 생성 과정 중 필연적으로 생성되는 부산물인 Methyl 4-formylbenzoate를 이용해 one-pot reaction을 통한 p-Aminobenzoic acid를 얻는 방법이다. 이 방법은 Methyl 4-formylbenzoate에 chlorine gas와 methylene chloride를 이용해 acid chloride를 형성하고 ammonia gas를 통해 amide를 중간체로 가진다. 생성된 amide는 Hofmann degradation을 통해 p-Aminobenzoic acid로 전환된다. 이 방법은 폐기물인 Methyl 4-formylbenzoate를 재활용하여 기존의 p-Aminobenzoic acid를 수율 90%로 합성하였으며 이는 기존의 p-Aminobenzoic acid 생산과정을 대체할 수 있을 것으로 예상된다.

• 에너지공학
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• 제26권1호
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• pp.54-61
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• 2017

In general, solid waste arises from lots of human activities such as domestic, agricultural, industrial, commercial, waste water treatment, construction, and mining activities etc. If the waste is not properly disposal and treated, it will have a negative impact to the environment, and hygienic conditions in urban areas and pollute the air with greenhouse gases (GHG), ground water, as well as the soil and crops. In this paper, the Carbon Resources Recycling Appropriate Technology Center feasibility studies are reported at Bantayan Island, Philippines on the municipal solid waste management. The present objective of our study is to characterize the municipal solid waste incineration (MSWI) bottom ash and case study of MSWI production status in Bantayan, Philippines. Currently, wide variety of smart technologies available for MSWI management in developed countries. Recycling is the other major alternative process for MSWI landfill issues. In this paper, the feasibility studies of applied appropriate technologies for the municipal solid waste generation in Bantayan Island, Philippines are reported.

• 말소리와 음성과학
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• 제10권3호
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• pp.41-48
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• 2018

This study examined the acoustic characteristics of Korean alveolar fricatives of normal children. Developing children aged 3 and 7, typically produced 2 types of nonsense syllables containing alveolar fricative /sV/ and /VsV/ sequences where V was any one of three corner vowels (/i, a, and u/). Stimuli containing the speech materials used in a production experiment were presented randomly to 12 speech language pathologists (SLPs) for a perception test. The SLPs responded by selecting one of seven alternative sounds. Acoustic measures such as duration of frication noise, normalized intensity, skewness, and center of gravity were examined. There was significant difference in acoustic measures when comparing vowels. Comparison of syllable structures indicated statistically significant differences in duration of frication noise and normalized intensity. Acoustic parameters could account for the perceptual data. Relating the acoustic and perception data by means of logistic regression suggests that duration of frication noise and normalized intensity are the primary cues to perceiving Korean fricatives.

• Molecules and Cells
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• 제45권11호
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• pp.771-780
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• 2022

The field of extracellular vesicles (EVs) has expanded tremendously over the last decade. The role of cell-to-cell communication in neighboring or distant cells has been increasingly ascribed to EVs generated by various cells. Initially, EVs were thought to a means of cellular debris or disposal system of unwanted cellular materials that provided an alternative to autolysis in lysosomes. Intercellular exchange of information has been considered to be achieved by well-known systems such as hormones, cytokines, and nervous networks. However, most research in this field has searched for and found evidence to support paracrine or endocrine roles of EV, which inevitably leads to a new concept that EVs are synthesized to achieve their paracrine or endocrine purposes. Here, we attempted to verify the endocrine role of EV production and their contents, such as RNAs and bioactive proteins, from the regulation of biogenesis, secretion, and action mechanisms while discussing the current technical limitations. It will also be important to discuss how blood EV concentrations are regulated as if EVs are humoral endocrine machinery.