• Title/Summary/Keyword: material recovery

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Improvement of sugar recovery from Sida acuta (Thailand Weed) by NaOH pretreatment and application to bioethanol production

  • Siripong, Premjet;Doungporn, Premjet;Yoo, Hah Young;Kim, Seung Wook
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2413-2420
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    • 2018
  • Sida acuta, a common type of weed in Thailand, contains relatively high cellulose (42.7%) content. We pretreated NaOH to improve glucose recovery from S. acuta. The effect of pretreatment temperature and NaOH concentration was fundamentally investigated based on hydrolysis efficiency with recovery of solid fraction. The pretreatment condition was determined to be 3% NaOH at $60^{\circ}C$ for 9 h, which showed the highest glucose recovery. The hydrolysates obtained by enzymatic hydrolysis of S. acuta were applied to the fermentation of Saccharomyces cerevisiae K35, and a theoretical yield of 97.6% was achieved at 18 h. This indicated that the hydrolysates medium without detoxification had no negative effects on the fermentation. The production of biomass into bioethanol was evaluated based on the material balance of 1,000 g basis. Following this estimation, approximately 28 g and 110 g bioethanol could be produced by untreated and pretreated S. acuta, respectively, and this production was improved about 3.9-fold by NaOH pretreatment. These results again show the importance of pretreatment in biorefinery process.

SYNTHESIS, CHARACTERIZATION AND APPLICATION OF WATER-SOLUBLE AND WATER-SWELLING POLYMERS BASED ON VINYL ETHERS

  • Kudaibergenov, Sarkyt-E
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.467-470
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    • 1998
  • The scientiic and technological aspects of water-soluble and water-swelling polymers to be synthesized from the domestic raw materials of Kazakhstan are described. The application area of polymeric reagents in medicine, biotechnology, agriculture, enhanced oil recovery, ecology is also considered.

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Factors Affecting Recovery of Spontaneous Circulation in Patients Before Cardiac Arrest in Emergency Department: 2012~2016 Focused on Medical Records Data (응급실 도착 전 심정지 환자의 자발순환 회복 여부에 미치는 요인 -2012~2016 의무기록 자료를 중심으로-)

  • Kim, Seok-hwan
    • The Korean Society of Law and Medicine
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    • v.19 no.2
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    • pp.209-233
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    • 2018
  • The purpose of this study was to ascertain whether or not to recover the spontaneous circulation of patients with cardiac arrest before arrival in the emergency room for 5 years (2012 to 2016), and try to investigate the factors affecting this. In this research, we used the "raw material for acute cardiac arrest survey" conducted in "Disease management headquarters" from 2012 to 2016 for the whole country of our country as the main material. In this study, 136,212 cardiac arrest patients were analyzed in the study data of the cardiac arrest in the country during the 5 years from 2012 to 2016. We performed a Chi-square analysis to analyze the recovery of spontaneous circulation before arrival in the emergency room according to general characteristics, social·demographic characteristics, and developmental characteristics. and We performed a Binary logistic regression analysis to determine the factors affecting the recovery of spontaneous circulation. The analysis results of this study show that whether CPR sustained transport before endoplasmic reticulum arrival, whether to witness an acute cardiac arrest before arrival in the emergency room, the type of general cardiopulmonary resuscitation, the location of acute cardiac arrest, the acute heart Causes of stoppage cause factor of whether spontaneous circulation recovery recovers before arrival of the endoplasmic reticulum(P<0.001, P<0.01). Therefore, it is necessary to strengthen systematic government health policy implementation and dissemination and health education focusing on factors that affect recovery of spontaneous circulation of cardiac arrest patients.

A Study of Estimation of Greenhouse Gas Emission and Reduction by Municipal Solid Waste (MSW) Management (D시 생활폐기물 관리 방법과 온실가스 배출량과 감축량 산정 연구)

  • Yun, Hyunmyeong;Chang, Yun;Jang, Yong-Chul
    • Journal of Korea Society of Waste Management
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    • v.35 no.7
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    • pp.606-615
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    • 2018
  • Over the past two decades, the options for solid waste management have been changing from land disposal to recycling, waste-to-energy, and incineration due to growing attention for resource and energy recovery. In addition, the reduction of greenhouse gas (GHG) emission has become an issue of concern in the waste sector because such gases often released into the atmosphere during the waste management processes (e.g., biodegradation in landfills and combustion by incineration) can contribute to climate change. In this study, the emission and reduction rates of GHGs by the municipal solid waste (MSW) management options in D city have been studied for the years 1996-2016. The emissions and reduction rates were calculated according to the Intergovernmental Panel on Climate Change guidelines and the EU Prognos method, respectively. A dramatic decrease in the waste landfilled was observed between 1996 and 2004, after which its amount has been relatively constant. Waste recycling and incineration have been increased over the decades, leading to a peak in the GHG emissions from landfills of approximately $63,323tCO_2\;eq/yr$ in 2005, while the lowest value of $35,962tCO_2\;eq/yr$ was observed in 2016. In 2016, the estimated emission rate of GHGs from incineration was $59,199tCO_2\;eq/yr$. The reduction rate by material recycling was the highest ($-164,487tCO_2\;eq/yr$) in 2016, followed by the rates by heat recovery with incineration ($-59,242tCO_2\;eq/yr$) and landfill gas recovery ($-23,922tCO_2\;eq/yr$). Moreover, the cumulative GHG reduction rate between 1996 and 2016 was $-3.46MtCO_2\;eq$, implying a very positive impact on future $CO_2$ reduction achieved by waste recycling as well as heat recovery of incineration and landfill gas recovery. This study clearly demonstrates that improved MSW management systems are positive for GHGs reduction and energy savings. These results could help the waste management decision-makers supporting the MSW recycling and energy recovery policies as well as the climate change mitigation efforts at local government level.

A Numerical Study of Heat and Mass Transfer Phenomena for Thermal Protection Material (열보호재료의 열 및 물질전달 현상에 관한 수치해석적 연구)

  • Kim, Jung-Hoon;Kwon, Chang-Oh;Seo, Jeong-Il;Bai, Cheol-Ho;Song, Dong-Joo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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    • pp.1201-1212
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    • 1999
  • A numerical analysis is performed to predict the thermal response and ablation rate for charring or non-charring material which is designed to be used as thermal protection system (TPS). The numerical program composed of in-depth energy balance equation and the aerotherm chemical equilibrium (ACE) program. The ACE program calculates various thermochemical state from ablation products. The developed numerical program is verified by comparing the reported results from literature. The sensitivity tests for input parameters are performed. The thermal behavior of ablating material is mainly affected by density of ablating material, convective heat transfer coefficient and recovery enthalpy of flow field.

Verification of Applicability of Emergency Recovery Scenario Applying Field Recovery Case (현장복구사례를 이용한 긴급복구 시나리오의 적용성 검증)

  • Yoon, Hyuk-Jin;Jung, Jae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.2
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    • pp.632-638
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    • 2018
  • Recently, damage to waterside structures, such as bridges or retaining walls, is increasing due to typhoons, flooding, aging, etc. In such cases, the damage is not limited to the structures themselves, but can include effects on a wider scale, such as the suspension of and restriction of access to the facilities, human injury, economic loss, etc. To preclude such damage, recovery methods suitable for the particular field circumstances should be applied when damage occurs. By enforcing prompt repairs, the material and human damage and losses that can occur can be minimized. Since the impact of losses caused by damage and disaster increases with the elapse of time, emergency recovery is even more important. In the emergency recovery process, appropriate repair and reinforcement is crucial. In the present study, the derivation scenarios of the emergency recovery method were applied to some field recovery cases, and their applicability was verified by comparison with the recovery methods actually used. It is expected that the results of this study will be useful for practical application, by suggesting more appropriate recovery methods.

Effect to Material Strength Recovery of Stepped Patch Repair with Epoxy based Particle Reinforced GFRP Composites under Hygrothermal Environment (에폭시 기지 입자 강화 GFRP를 사용한 계단형 패치 보수법이 고온 고습 환경하에서 재료의 물성 회복에 미치는 영향)

  • Jung, Kyung-Seok;Park, Soo-Jeong;Kim, Yun-Hae
    • Composites Research
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    • v.31 no.3
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    • pp.88-93
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    • 2018
  • In this study, damaged composite laminates were repaired by a stepped patch repair method using halloysite nanotube(HNT) and milled carbon(MC) reinforced composite materials with different amount of the particles. And the mechanical and structural effects of the particles on the interface between the damaged and repair surfaces were analyzed. At this time, after exposing them to a harsh environment of high temperature and humidity for a long time, the recovery rate of the material properties relative to the material forming the damaged plate was compared. As a result, at $70^{\circ}C$ high temperature distilled water, the hygroscopicity of the HNT/GFRP composites was significantly different from that of the MC/GFRP composites. Especially, 0.5, 1 wt. % HNT was added, the moisture absorption rate was the lowest and this was the factor that contributed to the mechanical strength increase. On the other hand, MC showed a high hygroscopic resistance only with a small amount, and the strength was different according to the action direction of the load, and the addition amount was also different.

Analysis of Physical Performance, Hygiene and Safety of Silicone-Laminated Stretch Material (실리콘이 라미네이팅된 신축성 소재의 위생 및 안전성과 역학적 성능)

  • Kwon, Myoung-Sook;Jung, Gi-Soo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.1 s.160
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    • pp.77-84
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    • 2007
  • The purpose of this study was to investigate and to compare the performances of silicone laminated materials sold for swimming cap in market, to get the basic data for product development. We selected 4 specimens and tested their air permeability, waterproofness and breathability. We also tested the physical and mechanical properties of the specimens using KES system. Silicone-laminated material was not bursted on high hydraulic pressure since silicone membrane gave waterproofness while PU/Polyester substrate gave elasticity. It didn't have air permeability and breathability at all. Any toxic materials such as Formaldehyde, Deldrin, PCP, Amin, TDBPP were not detected in silicone-laminated material and other materials. Silicone-laminated material had higher stretchability with the low force but it had lower elastic recovery and shape stability comparing to PU laminated material. It had lower flexibility than PU laminated material. It had lower unrecoverable amount in shearing direction. Friction coefficient was higher in silicone-laminated material than PU laminated material due to its surface stickiness. It was compressed easily and its compression resiliency was higher with compared to PU laminated material.

Difference of Neuronal Recovery by Incubation Condition after Transient Hypoxia (배양조건에 의한 일과성 저산소상태 후 신경세포회복의 차이)

  • Moon, Soo-Hyeon;Oh, Jae-Inn;Park, Youn-Kwan;Chung, Heung-Sub;Lee, Hoon-Kap;Lee, Ki-Chan
    • Journal of Korean Neurosurgical Society
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    • v.29 no.9
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    • pp.1161-1170
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    • 2000
  • Objective : The transverse hippocampal slice is one of the most commonly studied in vitro models of mammalian brain physiology. However, despite its broad usage, there has been no standardization of slice preparation techniques or recording condition. It is well known that variations in recording conditions can result in profound different effects to neuronal responses. Evoked field potentials, recorded extracellularly, were used to investigate the effects of variations in hippocampal slice preparation protocol on hypoxia responses of CA1 neurones. Material & Methods : Before hypoxic injury, hippocampal slices were incubated for 4 hours. During incubation period, the slices were placed in a incubation chamber($21^{\circ}C$) for recovery from preparation injury and then transferred to recording chamber($34^{\circ}C$) for more recovery and baseline electric recording with current stimulation(0.1Hz). Various time periods in incubation chamber and recording chamber were applied to each experimental group(group 1=60min : 180min, group 2=90min : 150min, group 3=180min : 60min, time in incubation chamber : time in recording chamber) before 10 min hypoxia produced by replacing 95% $O_2$+5% $CO_2$ mixed gas to 95% $N_2$+5% $CO_2$ gas. Calcium, Magnesium ions and several drugs effecting on glutamate receptor also were studied. Recoveries from hypoxic injury of hippocampal slices were estimated by percent recovery of population spike(PS). Statistic analysis of study were performed using paired t-test. Results : The percent recovery of PS after 10min hypoxia was considerably enhanced by increasing the period of current stimulation during incubation period before hypoxic injury. Temperature effect on the result of this experiment was also studied(group 4) but the result from this showed no statistic significance. Low magnesium ion concentration of artificial CSF(Mg-free aCSF) during incubation period enhanced the recovery of PS but low calcium (calcium-free) and high magnesium ion concentration(2mM) reduced it after hypoxic injury. L-glutamate($100{\mu}M$) and AP-5($50{\mu}M$) had no effect on the recovery of PS but CNQX($10{\mu}M$) in artificial CSF during incubation period markedly enhanced the recovery of PS. Co-treatment of AP-5($50{\mu}M$), CNQX($10{\mu}M$) and high magnesium concentration(2mM) enhanced recovery of PS in immediate following period of hypoxic injury but the effect of cotreatment after then decayed rapidly and lost statistic significance. Conclusions : Judging from above results, the condition of baseline recording is important in observing the recovery of population spike after hypoxia, and the time and the condition should be controled more strictly to obtain reliable results.

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