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An Effective Acid Catalyst for Biodiesel Production from Impure Raw Feedstocks
Hai-Linh Tran,류영진,성동호,임상민,이철균 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2
Biodiesel consists of fatty acids short chain alkyl esters produced through transesterification and esterification of fats and oils. Production of biodiesel is strongly affected by the purity of raw lipids, and catalysts play important role in these processes. Although direct utilization of impure feedstocks is more economical, their use necessitates development of effective catalysts to overcome hindering influences of impurities. In this study,sulfuryl chloride, thionyl chloride, acetyl chloride, ptoluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, dimethylsulfate and sulfuric acid were investigated as catalysts for the production of biodiesel because acids have higher tolerance to water and free fatty acids in oils and can simultaneously catalyze both the esterification and transesterification reactions. Sulfuryl chloride was found to be an effective catalyst for production of biodiesel from soybean oil, its waste oil and microalgal lipids.
A Quality Management Framework for Seaports in their Supply Chains in the 21st Century
Hai TRAN,Stephen CAHOON,SHU-LING CHEN 한국해운물류학회 2011 The Asian journal of shipping and Logistics Vol.27 No.3
For seaports to be competitive and sustainable in the long-term in a turbulent and hyper-competitive market, a re-examination of success factors, organizational structures, and management practices is required. As seaports have continued to evolve and become further integrated and embedded in their supply chains, the issue of ensuring quality management practices becomes of greater interest. This paper argues that the seaport should implement relevant and appropriate internal and external quality management practices. The former emphasizes more internal-focused quality management practices relating directly to the seaport, while external quality management practices aim to facilitate the efficiency of supply chains in which the seaport is embedded as well as harmonizing the relationships with stakeholders. This paper takes a conceptual approach to these issues by comprehensively reviewing the extant literature and proposes a quality management framework for empirical validation containing eight internal and four external quality management practices for seaports in the twenty-first century.
( Hai The Pham ),( Phuong Ha Vu ),( Thuy Thu Thi Nguyen ),( Ha Viet Thi Bui ),( Huyen Thanh Thi Tran ),( Hanh My Tran ),( Huy Quang Nguyen ),( Byung Hong Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.10
Sediment bioelectrochemical systems (SBESs) can be integrated into brackish aquaculture ponds for in-situ bioremediation of the pond water and sediment. Such an in-situ system offers advantages including reduced treatment cost, reusability and simple handling. In order to realize such an application potential of the SBES, in this laboratory-scale study we investigated the effect of several controllable and uncontrollable operational factors on the in-situ bioremediation performance of a tank model of a brackish aquaculture pond, into which a SBES was integrated, in comparison with a natural degradation control model. The performance was evaluated in terms of electricity generation by the SBES, Chemical oxygen demand (COD) removal and nitrogen removal of both the tank water and the tank sediment. Real-life conditions of the operational parameters were also experimented to understand the most close-to-practice responses of the system to their changes. Predictable effects of controllable parameters including external resistance and electrode spacing, similar to those reported previously for the BESs, were shown by the results but exceptions were observed. Accordingly, while increasing the electrode spacing reduced the current densities but generally improved COD and nitrogen removal, increasing the external resistance could result in decreased COD removal but also increased nitrogen removal and decreased current densities. However, maximum electricity generation and COD removal efficiency difference of the SBES (versus the control) could be reached with an external resistance of 100 Ω, not with the lowest one of 10 Ω. The effects of uncontrollable parameters such as ambient temperature, salinity and pH of the pond (tank) water were rather unpredictable. Temperatures higher than 35℃ seemed to have more accelaration effect on natural degradation than on bioelectrochemical processes. Changing salinity seriously changed the electricity generation but did not clearly affect the bioremediation performance of the SBES, although at 2.5% salinity the SBES displayed a significantly more efficient removal of nitrogen in the water, compared to the control. Variation of pH to practically extreme levels (5.5 and 8.8) led to increased electricity generations but poorer performances of the SBES (vs. the control) in removing COD and nitrogen. Altogether, the results suggest some distinct responses of the SBES under brackish conditions and imply that COD removal and nitrogen removal in the system are not completely linked to bioelectrochemical processes but electrochemically enriched bacteria can still perform nonbioelectrochemical COD and nitrogen removals more efficiently than natural ones. The results confirm the application potential of the SBES in brackish aquaculture bioremediation and help propose efficient practices to warrant the success of such application in real-life scenarios.
A New Structure of MR Brake with the Waveform Boundary of Rotary Disk
Tran Hai NAM,Kyoung Kwan AHN 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
This paper presents a new structure of a Magneto Rheological (MR) brake which generates the resistance force based on the effect of material deformation process. A rotary disk is proposed and fabricated with the wave form boundary. Thus, the chains of an MR fluid are crushed together instead of being strained to break as known in the conventional design. The phenomenon of mechanical destruction creates a stronger resistance force than the conventional one.