Novel hybrid models of ANFIS and metaheuristic optimizations (SCE and ABC) for prediction of compressive strength of concrete using rebound hammer field test

In this study, we developed novel hybrid models namely Adaptive Neuro Fuzzy Inference System (ANFIS) optimized by Shuffled Complex Evolution (SCE) on the one hand and ANFIS with Artificial Bee Colony (ABC) on the other hand. These were used to predict compressive strength (Cs) of concrete relating to thirteen concrete-strength affecting parameters which are easy to determine in the laboratory. Field and laboratory tests data of 108 structural elements of 18 concrete bridges of the Ha Long-Van Don Expressway, Vietnam were considered. The dataset was randomly divided into a 70:30 ratio, for training (70%) and testing (30%) of the hybrid models. Performance of the developed fuzzy metaheuristic models was evaluated using standard statistical metrics: Correlation Coefficient (R), Root Mean Square Error (RMSE) and Mean Absolute Error (MAE). The results showed that both of the novel models depict close agreement between experimental and predicted results. However, the ANFIS-ABC model reflected better convergence of the results and better performance compared to that of ANFIS-SCE in the prediction of the concrete Cs. Thus, the ANFIS-ABC model can be used for the quick and accurate estimation of compressive strength of concrete based on easily determined parameters for the design of civil engineering structures including bridges.     

五十年代中国援助越南发展高等教育的历史考察——以中央学舍区为例

二战之后至抗法独立战争期间,越南避开战火,在中国广西壮族自治区内建立起所谓的＂中央学舍区＂,以期为独立战争和战后国家建设培养骨干人才。＂中央学舍区＂从1951年10月1日成立到1958年结束,虽只存在短短几年,但其培养的大批人才,为越南高等教育的奠基和发展作出了突出贡献。本文作者通过大量查阅中越两国联合办学的有关历史文献和访谈资料,梳理了中央学舍区学校成立的艰难历程和办学情况,为研究战争期间或者其他关键时期如何进行教育实践活动提供了生动有趣的例子。而对于中国来说,由于当时刚刚建立新的国家政权,并且面临着抗美援朝战争的严峻形势,其对于越南的援助更彰显了一种大国风范,意义重大。     

BACH HO FIELD, A FRACTURED GRANITIC BASEMENT RESERVOIR, CUU LONG BASIN, OFFSHORE SE VIETNAM: A "BURIED-HILL" PLAY

A combination of seismic, wireline, FMI and core data shows that Bach Ho field in the Cuu Long Basin, offshore SE Vietnam, is an unusual “buried hill” reservoir. There is little or no production from associated siliciclastic “grus” or granite wash, and the fractured reservoir matrix is largely made up of unaltered acid igneous lithologies (mostly granites and granodiorites). A major NE‐SW late Oligocene reverse fault system cross‐cuts the field, with about 2000 m of lateral displacement in the highly productive Central Block. The associated fracture meshwork greatly enhances reservoir quality. Transpressional wrench faulting in the late Oligocene in this part of the field emplaced a block of brittle granitic rock on top of organic‐rich Eocene – Oligocene mudstones, and facilitated the early migration of hydrocarbons into the fracture network. Structure, not erosion, set up the 1000 m column of liquids in the fractured granodiorites which form the reservoir at Bach Ho. Faulted intervals with associated damage zones create an enhanced secondary porosity system in the granodiorite; effective porosities range from 3‐5% and occasionally up to 20%. Some associated fractures are partially blocked by authigenic calcite and kaolinite. Features that degrade reservoir quality at Bach Ho include: (i) a thin, low‐permeability clay‐plugged “rind” created by surface‐related (meteoric) Eocene – Oligocene weathering — this rind variably overprints the uppermost 10‐40 m of exposed basement throughout the Cuu Long Basin; and (ii) widespread hydrothermal cements which largely predate late Oligocene wrench faulting; cementation mostly took place during post‐magmatic cooling and precipitated zeolites, carbonates and silica in fractures which cut across both the igneous and the country rocks. Porosity‐occluding hydrothermal and authigenic precipitates developed in pre‐existing fractures in the Bach Ho granodiorite. These pre– late Oligocene mineral‐filled fractures acted as zones of structural weakness during and after subsequent late Oligocene structural deformation. Together with new fractures formed during thrusting, the older fractures may have reopened during thrust emplacement, and subsequent gravitational settling of, the Central Block.     

越南石油生产和出口形势变化及其对中国的影响

对近年来越南原油和油品生产形势的变化以及未来将对中国的石油进出口产生的影响进行了探讨.越南石油产量自20世纪80年代后期起快速上升,至2006年达到峰值后迅速下降.越南为改变油品几乎全依靠进口的状况,近年来着手大力兴建炼厂,因而石油进出口形势将发生逆转.预计越南2013年后就可成为原油净进口国(进口量可达3×107～5×107t)且将大量出口油品.此外,越南还积极谋求其油气上游业务在国外的发展.随着越南向原油进口国、油品出口国的转变,不仅对中国的石油进、出口有一定的影响,也会对亚太地区(特别是东盟10国)的石油形势有较大的影响,使他们在原油市场、油品市场和国际石油勘探开发市场上都多了一个竞争者和潜在的合作伙伴.     

Design and performance evaluation of a Double-pass solar drier for drying of red chilli (Capsicum annum L.)

Performances of a new designed Double-pass solar drier (DPSD) were compared with those of a typical cabinet drier(CD) and a traditional open-air sun drying for drying of red chilli in central Vietnam. The drying times (including nights) to reach the desired moisture content of 10% (on a wet basis) were 32 and 73 h respectively. During open-air sun drying the desired moisture content of 10% (on a wet basis) could not be reached even after 93 h of drying (including nights). The overall drying efficiencies of DSPD and CD to reach the desired moisture content of 10% (on a wet basis) were 24.04% and 11.52% respectively while the overall drying efficiency of open-air sun drying to reach the desired moisture content of 15% (on a wet basis) was 8.03%. Further, ASTA colour value of the solar dried products from the DSPD was higher than those from CD and open-air sun drying. Similar results were obtained for mycotoxins occurrence. Contamination by aflatoxin B1 was significantly lower in dried chilli from DPSD (<0.250 μg kg⁻¹) when compared to traditional open-air drying technique (11.980 μg kg⁻¹). The drying cost per one kilogram of chilli was 39% lower in case of DPSD (0.077 US$/kg) as compared to CD (0.126 US$/kg). The Double-pass solar drier was found to be technically suitable and economically viable for drying of red chillies in central Vietnam.     

越南股票市场联动性研究—基于GRANGER因果关系检验-GARCH模型实证分析

选取2006年1月4日至2013年12月1日越南指数与河内指数的日收盘价数据,采用格兰杰因果检验、脉冲响应函数和GARCH模型实证分析越南股票市场间收益率和波动率的联动性。实证结果表明:越南指数与河内指数的联动效应较弱,虽然两者之间存在引导关系,但两者对来自自身的新冲击表现出更明显的反应,市场存在明显的"杠杆效应"。     

通过PLC实现厂用备自投的工程实践

文章以越南宝路水电站厂用电备自投的设计为例,综合比较了各种实现方式,介绍了用可编程控制器(PLC)实现备自投功能的设计思路,提出了备自投动作的初步流程方案。工程实践证明,用PLC实现厂用电备自投是可行的。     

Reducing reservoir impacts and improving outcomes for dam‐forced resettlement: experiences in central Vietnam

The present study focuses on the growing problem of the impacts of human displacement resulting from hydropower dam construction, within the context of the integrated lake basin management of dam reservoirs. Dam‐forced displacement and resettlement can pose severe challenges to the environmental, economic and social sustainability of a reservoir basin. A case study in Quang Nam Province, central Vietnam, suggests that many resettled communities experience impoverishment due to the lack of adequate replacement land, declines in supplemental food sources and reduced access to natural resources. In response to such situations, resettled residents may (i) destroy lake catchment forests for the purpose of converting them to farmland or engage in illegal logging; (ii) increase agrichemical inputs on reduced land, thereby polluting run‐off and groundwater; and (iii) place increased pressure on fish stocks and wildlife. Examples are provided from central Vietnam to illustrate the need for applying management approaches that allows the affected people to become beneficiaries of dam projects and for including civil society organisations in resettlement planning. The hydropower authority can fund benefit‐sharing mechanisms, including village‐level electrification and payment for environmental services schemes, in which resettled populations are paid for forest maintenance and protection to prevent erosion and deforestation, and reservoir access can be provided for fishing, aquaculture and agriculture. Civil society organizations can advocate for residents’ interests and for reallocation of protected forest land for community forestry. These approaches can be supported by an inclusive reservoir management board working to achieve environmental sustainability, economic growth and social equity.     

Urea management for lowland transplanted rice as affected by application of farmyard manure

Farmyard manure (FYM) applied to rice-growing soils can substitute for industrial fertilizers, but little is known about the influence of FYM on the effectiveness and optimal management for industrial N fertilizers. A field experiment was conducted in northern Vietnam on a degraded soil in the spring season (February to June) and summer season (July to November) to determine the effect of FYM on optimal timing for the first application of urea. The experimental design was a randomized complete block with two rates of basal incorporated FYM (0 or 6 Mg ha^–1) in factorial combination with two timings of the first application of 30 kg urea-N ha^–1 (basal incorporated before transplanting or delayed until 14 to 16 d after transplanting). The FYM was formed by composting pig manure with rice straw for 3 months. Basal incorporation of FYM, containing 23 kg N ha^–1, increased rice grain yield in both seasons. The yield increase cannot be attributed to reduced ammonia loss of applied urea-N, because FYM did not reduce partial pressure of ammonia (pNH₃) following urea application in either season. Basal and delayed applications of urea were equally effective in the absence of FYM, but when FYM was applied rice yields in both seasons were higher for delayed (mean = 3.2 Mg ha^–1) than basal (mean = 2.9 Mg ha^–1) application of urea. Results suggest that recommendations for urea timing in irrigated lowland rice should consider whether farmers apply FYM.     

Screening determination of food additives using capillary electrophoresis coupled with contactless conductivity detection: A case study in Vietnam

In this study, a simple and inexpensive method for food analysis is discussed. The approach is based on capillary electrophoresis (CE) instruments with capacitively coupled contactless conductivity detection (C⁴D). Following the pilot deployment of in-house fabricated CE-C⁴D instruments in Vietnam, a number of food additives in different food matrices, including i) oxalate and citrate in instant noodles, beer and tea drinks, ii) acidulants in beverage, coffee, alcohol and vinegar samples, and iii) artificial sweeteners in jelly and drink samples, were determined using this method. Good agreement between results obtained with CE-C⁴D-instruments and those from the confirmation method (HPLC-PDA) was achieved.