Rice husk gasification for electricity generation in Cambodia in December 2014: Field trip report

Rice husks are the indigestible coatings of grains of rice. They are produced in large quantities by the rice milling industry, more than 1 million ton per year in Cambodia. In recent years, Cambodian enterprises have installed gasifiers, which burn rice husks to generate electricity. This is a two stage process: the biomass is first fed into a gasifier which produces syngas and ashes, then the syngas is cleaned and burned into an engine where it saves diesel fuel. Many of these enterprises have been in local communities currently without electricity or in fuel poverty.To learn more about the benefits and drawbacks of using rice-husk gasifiers, and to study about the sustainability challenges for deploying these technologies, the Clean energy and sustainable development lab (CleanED lab) of the University of Science and Technology of Hanoi (USTH), and the SNV Netherlands Development Organisation (SNV) have conducted a visit of several rice mills and rural electricity enterprises from 18 th to 22nd December 2014.Five rice mills and a rural electricity enterprise in Battambang, Siem Reap and Kampong Thom provinces were selected for the field survey. In addition with desk research, semi-structured interviews with gasifier users, with the representatives of Canadia Bank PLC and the Federation of Cambodian Rice Millers Association (FCRMA) during the field surveys were also conducted. This report present and justifies the main conclusions of the visit

Robust model predictive kinematic tracking control with terminal region for wheeled robotic systems

This paper addresses the nonlinear model predictive control (MPC) for wheeled mobile robots (WMRs) under external disturbance. The decoupling technique is utilized based on the non-holonomic constraint description for separating the WMR model. This method is able to achieve the under-actuated kinematic sub-system without disturbance and fully-actuated dynamic sub-system in presence of disturbance. Thanks to the decoupling technique, the disturbance is lumped into dynamic sub-system. The novelty lies in that the MPC-based tracking control with fixed initial point guarantees the stability based on a new establishment of terminal region and equivalent terminal controller. The feasibility problem is demonstrated to lead the tracking problem using theoretical analysis. Moreover, the control structure is inserted more the robust nonlinear dynamic controller. The effectiveness and advantages of the proposed control scheme are verified by numerical simulations using Yamip tool

Assessment of earthquake-induced ground liquefaction susceptibility for Hanoi city using geological and geomorphologic characteristics

In this paper, the earthquake-induced liquefaction susceptibility of Hanoi city is assessed using the recent published geological and geomorphologic data. A combination of classification methods based on the distribution of sedimentary deposits proposed by Youd and Perkins (1978) and geomorphologic units proposed by Iwasaki (1982) was applied. The subsurface lithology and geomorphologic maps were combined in a GIS platform for assessing the liquefaction susceptibility of Hanoi city.The resulting map shows that the liquefaction hazard of Hanoi city classified into four categories: high, moderate, low liquefaction potential and not likely areas. In the most of Hanoi area, the ground liquefaction potentials are moderate. The high liquefaction likely areas spread along the river beds and around the lake areas. The not likely and low liquefaction potential areas are observed mainly in the northwest and northeast of the study region such as Chanchim, Soc Son, and Bavi mountains. The present map can help the scientists, engineers, and planners to have the general information on regional liquefaction potential of the Hanoi city. ReferencesBird JF, Bommer JJ, 2004b. Earthquake Losses due to Ground Failure. Submitted to Engineering Geology, 75(2), 147-179.Bird Juliet F, Bommer Julian J., 2004a. Evaluating earthquake losses due to ground failure and identifying their relative contribution (Paper no. 3156). In Proceedings of the 13th world conference on earthquake engineering, Vancouver, B.C., Canada, august 1-6.Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La-Bac Yen fault zone. J. Sci. of the Earth, 35(1), 53-59.Dao Dinh Bac, Dang Van Bao, 2010. Geomorphologic characteristics, the ancient river beds system of the capital city and their values to the development of the Thang Long - Hanoi. International Workshop commemorating the 1000 years of Thang Long, Hanoi. Vietnam national University, Hanoi.Ganapathy, G. P., Rajawat, A. S., 2012. Evaluation of liquefaction potential hazard of Chennai city, India: using geological and geomorphological characteristics. Natural hazards, 64(2), 1717-1729.Goyal, A., Sinha, R., Chaudhari, M. and Jaiswal, K., 2001. Performance of Reinforced Concrete Buildings in Ahmedabad during Bhuj Earthquake January 26, 2001. Workshop on Recent Earthquakes of Chamoli and Bhuj: Volume I, Roorkee, India, May 24-26.Iwasaki, T., Tokida, K., Tatsuoka, F., Watanabe, S., Yasuda, S., Sato, H., 1982. Microzonation for soil liquefaction potential using simplified methods. In Proceedings of the 3rd international conference on microzonation, Seattle, 3, 1310-1330.Kuribayashi E., Tatsuoka, F., 1975. Brief review of liquefaction during earthquake in Japan,” Soils and Foundations, 15(4), 81-92.Lew M, Naeim F, Huang SC, Lam HK, Carpenter LD, 2000. Geotechnical and geological effects of the 21 September 1999 Chi-Chi earthquake, Taiwan. Structural Design of Tall Buildings, 9, 89-106.National Research Council, 1985. Ishihara 1985. Liquefaction of Soils During Earthquake, National Academy press, 240, p.34. Nguyen Hong Phuong (Project Manager), 2002. Study of seismic risk of Hanoi city. Project code 01C-04/09-2001-2. Institute for Marine Geology and Geophysics, VAST.Nguyen Hong Phuong (Project Manager), 2007. Application of GIS technology to Development of a model for seismic risk analysis for Hanoi city. Institute for Marine Geology and Geophysics, VAST.Nguyen Hong Phuong (Project Manager), 2014.  Estimation of Site Effects and Assessment of Urban Seismic Risk for Hanoi city. National Scientific Research Project Final report, Institute of Geophysics, VAST.Nguyen Hong Phuong and Pham The Truyen, 2014. Probabilistic seismic hazard assessment for South Central Vietnam. J. Sci. of the Earth, 36(4), 451-461.Phan Trong Trinh, Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. 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Multi parametric model predictive control based on laguerre model for permanent magnet linear synchronous motors

The permanent magnet linear motors are widely used in various industrial applications due to its advantages in comparisons with rotary motors such as mechanical durability and directly creating linear motions without gears or belts. The main difficulties of its control design are that the control performances include the tracking of position and velocity as well as guarantee limitations of the voltage control and its variation. In this work, a cascade control strategy including an inner and an outer loop is applied to synchronous linear motor. Particularly, an offline MPC controller based on MPP method and Laguerre model was proposed for inner loop and the outer controller was designed with the aid of nonlinear damping method. The numerical simulation was implemented to validate performance of the proposed controller under voltage input constraints

A critical look at rice husk gasification in Cambodia: Technology and sustainability

International audienceIn recent years, many Cambodian enterprises have installed rice husk gasifiers to substitute diesel in the electricity production to run rice mills machinery, or to provide electricity for villages. This study provides a critical look at rice husk gasification by assessing the sustainability of deploying this technology in Cambodia, expressed through environmental, economic and social impacts, and evaluates if it can be applied in Vietnam. Results show that gasification technology works in Cambodia and contribute to the development of the rice-milling sector, however environmental issues are severe and should be treated. We observe that increase in rice husk demand also leads to increase in price of rice husk, therefore new investors should consider the effect of new rice husk market for their activities. We conclude that this technology would not be suitable for Vietnam and suggests studying other alternative technologies to convert rice husk into energy, such as steam engine or steam turbine, gasifier stove, briquetting or co-firing

Examination of influential factors on shear strength of externally bonded FRP reinforcement in RC beams

The fiber-reinforced polymer (FRP) retrofitting technique has been increasingly created to enhance the capacity of the existing concrete members. In this study, the shear contribution of the external FRP strengthening system in the reinforced concrete (RC) beams is estimated by the semi-empirical models available in the open literatures and guidelines. Number of beams monitored in the previous studies are first considered to assess the reliability of the models. Afterwards, the investigation of influential factors such as the beam configurations, the strengthening characteristics and the material properties are implemented. With high accuracy and low coefficient of variation, the model proposed in a previous study of the authors gains the mostly considerable estimation for the shear resisting strength of FRP strengthening system compared to the accessible data base from the experiments. In addition, the critical properties of the materials associating with the retrofitting systems for the strengthened beams are investigated to obtain the acquired shear performance