Numerical solution of the problems for plates on some complex partial internal supports

In the recent works, Dang and Truong proposed an iterative method for solving some problems of plates on one, two and three line partial internal supports (LPISs), and a cross internal support. In nature they are problems with strongly mixed boundary conditions for biharmonic equation. For this reason the method combines a domain decomposition technique with the reduction of the order of the equation from four to two. In this study, the method is developed for plates on internal supports of more complex configurations. Namely, we examine the cases of symmetric rectangular and H-shape supports, where the computational domain after reducing to the first quadrant of the plate is divided into three subdomains. Also, we consider the case of asymmetric rectangular support where the computational domain needs to be divided into 9 subdomains. The problems under consideration are reduced to sequences of weak mixed boundary value problems for the Poisson equation, which are solved by difference method. The performed numerical experiments show the effectiveness of the iterative method

Multicriteria Evaluation Of Tourism Potential In The Central Highlands Of Vietnam: Combining Geographic Information System (GIS), Analytic Hierarchy Process (AHP) And Principal Component Analysis (PCA)

Tourism potential provides an indication for the tourism development opportunities of regions and sites. This paper deals with a multicriteria evaluation of the tourism potential in the Central Highlands of Vietnam. The study area is located in the Southeast Asian monsoon tropical climatic zone, and offers both natural and cultural tourism resources. GIS-based cost distance analysis was used to calculate the travel time along the road and using other transportation networks. Then an Analytic Hierarchy Process (AHP) was applied to determine a weighting coefficient for each criterion in multicriteria evaluation. Principal Component Analysis (PCA) was processed next to AHP, allowing combination of the internal and external tourism potentials of the considered sites. Both AHP and PCA approaches were based on a certain number of alternatives, and take multiple criteria and conflicting objectives into consideration. The results show that the Central Highlands have considerable potential for tourism development at 99 potential eco-tourism sites and 45 potential cultural tourism sites. However, the region is now faced with poor tourism infrastructure with low external potential. An improvement of tourism infrastructure, service quality, and strengthened linkages with other tourist sites is indicated to diversify the tourism products and increase the attractiveness of regional destinations

Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss

BACKGROUND: This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. METHODS: In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. RESULTS: The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. CONCLUSIONS: This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength

LAKESCAPE UNDER URBAN DEVELOPMENT IN DONG DA DISTRICT, HANOI CITY

Joint Research on Environmental Science and Technology for the Eart

THE INFRASTRUCTURE AND ENVIRONMENT IN THE OLD TENEMENTS IN HANOI

Joint Research on Environmental Science and Technology for the Eart

Some natural heritages of outstanding values for tourism development in Central Highland

Tay Nguyen or the Central Highland with the remains of Archean relics is known as the region of the oldest natural formation across Vietnam’s territory. Had been taking place in the Central Highland the combined tectonic activities with typical exogenous process of the Cenozoic. Tay Nguyen contains many valuable natural resources, especially natural heritages that facilitate the development of ecotourism and scientific tourism. Scope of the TN3/T18 national project as part of the Central Highland Program 3 mainly covers research on the outstanding values, including 1) Some areas of extraordinary beauty and aesthetic value such as Dray Nur and Dray Sap waterfalls on the Serepok River in Dak Lak and Dak Nong provinces. 2) Fossil of the yews discovered in the Chu A Thai mountain, Phu Thien district, Gia Lai province; 3) Typical “living fossil plants” of the Central Highland that still exist such as yews (Glyptostrobus pensilis) and two flat-leaf pine-trees (Ducampopinus krempfii) in Gia Lai and Lam Dong; 4) Stone of the Kan Nack series (NA-PP) that is one of the oldest nationwide in basins of the Ba river, Gia Lai province; 5) Spectacular volcano landscape in Gia Lai and Kon Tum; 6) The unique cave system in the Krong No area, formed in basalt layer, is of fundamental difference from Vietnam’s popular limestone caves.ReferencesBonface B. G., Cooper C., 2012: Worldwide Destinations: The Geography of Travel and Tourism, Publishing House Routledge, p.610. Võ Văn Chi. 2004: Từ điển Thực vật thông dụng (Tập 2). Nxb. Khoa học và Kỹ thuật, Hà Nội, 2698tr. La Thế Phúc, Trương Quang Quý, Đỗ Chí Kiên, 2010: Di sản địa chất liên quan đến đá basalt ở Tây Nguyên và các giải pháp bảo tồn phát triển bền vững. Số đặc biệt kỷ niệm 65 năm ngày truyền thống ngành Địa chất Việt Nam. TC Địa chất. Hà Nội, 320, 514-521. La Thế Phúc, Lương Thị Tuất, Trương Quang Quý, 2012: Hang động trong đá basalt ở Cư Jut, Đắk Nông, Việt Nam. Hội nghị Công viên Địa chất Toàn cầu năm 2012 tại Unzen, Nhật Bản, tháng 5/2012. Nguyễn Thành Mến, 2013: Một số đặc điểm quần thể và phân bố loài Thông hai lá dẹt (Pinus krempfii H. Lec) ở Lâm Đồng. Tạp chí Khoa học Lâm nghiệp số 1, năm 2012, tr.2095-2104. Trương Quang Quý, La Thế Phúc, 2010: Trinh Nữ waterfall geologicall heritage, Đắk Nông province. Journal of Geology; series B.35-36/2010; 131-139. Hà Nội: Department of Geology and Minerals of Vietnam. H. Tachihara, TS. T. Honda, 2014: Báo cáo kết quả nghiên cứu sơ bộ các hang động núi lửa ở Đắk Nông, Việt Nam. Hội nghị Thông cáo báo chí “Công bố kết quả khảo sát hang động núi lửa tại khu vực Krông Nô, tỉnh Đắk Nông, Tây Nguyên Việt Nam” ngày 26/12/2014 tại Tổng cục Địa chất và Khoáng sản Việt Nam, số 6 Phạm Ngũ Lão, Hà Nội. Tong Dzuy Thanh, Vu Khuc (Editors), et al., 2006: Stratigraphical units of Vietnam. Vietnam National University Publishing House. Hanoi. 528 pgs. (2012 in lần thứ 2). Trần Văn Trị, Vũ Khúc (Editors) và nnk. 2012: Geology and Earth Resources of Vietnam. Publishing House for Science and Technology, Hanoi. 636 pgs. Wolfgang Eder, 2004: Geoparks - geological attractions: A tool for public education, recreation and sustainable economic development. UNESCO, Division of Earth Sciences, 1, rue Miollis, F-75732 Paris Cedex 15, France.

A case study on trade in threatened Tiger Geckos (Goniurosaurus) in Vietnam including updated information on the abundance of the Endangered G. catbaensis

Tiger geckos of the genus Goniurosaurus are considered as a susceptible reptile group, due to their restricted distribution ranges, specialisation to specific microhabitats and generally low population densities. While still new species have been discovered recently, Goniurosaurus species are threatened by extinction through habitat loss and collection for the pet trade. Of the 19 described species, for only eight species, the conservation status has been assessed within the IUCN Red List between 2016 and 2018 and all have been classified in the threat categories VU (Vulnerable), EN (Endangered) and CR (Critically Endangered). Goniurosaurus spp. are popular in the international pet market at least since the 1990s and several species experienced local extirpations as a consequence of massive over-collection in the past. However, tiger geckos have not been paid much attention for conservation, amongst others, due to the lack of comprehensive knowledge on their conservation status and biology. This study provides an overview of international trade in Goniurosaurus based on available data from 1999 to 2018 in the U.S. as well as data from online surveys and interviews in Europe and Vietnam, with the main focus on species native to Vietnam. All five tiger gecko species known from Vietnam were found in the local trade as wild captures for the national and international market and / or in the U.S. and Europe for relatively higher prices. We found that entire trade chains are very long (including several transfers and dealers involved) and that keeping and transport happen under poor conditions. We herein provide updated information on the abundance of the Endangered Cat Ba Tiger Gecko, which was recently shown to not only occur at its type locality, Cat Ba Island, Hai Phong City, North Vietnam, but also to inhabit small offshore islands in the Ha Long Bay, Quang Ninh Province. While the wild effective population was found to be relatively stable on four islands in Ha Long Bay, consisting of about 124 and 129 individuals in July 2017 and April 2018, respectively, the abundance of other sub-populations, impacted by anthropogenic pressures were found to be very low (2–10 individuals). Based on our findings, we propose stringent conservation measures to more efficiently protect wild tiger gecko populations, such as the inclusion in the Governmental Decree in Vietnam, the assessment of remaining species in the IUCN Red List of Threatened Species and the inclusion in the Appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

LAND USE CHANGE AND RELATED PROBLEMS UNDER URBANIZATION IN SUBURBAN AREA OF HANOI CITY (A CASE STUDY OF HOANG LIET COMMUNE, THANH TRI DISTRICT)

Joint Research on Environmental Science and Technology for the Eart

Influence of biofertilizer produced using drumstick (Moringa oleifera L.) unused parts on the growth performance of two leafy vegetables

The non-edible parts of Moringa oleifera, such as stems, branches or leaf petioles, have often been discarded while the leaves are consumed as a vegetable or are used to produce organic fertilizer. This study aimed to determine the optimal conditions for producing Moringa organic fertilizer (MOF) from previously unused parts and to compare these fertilizers with cow manure and bio-organic fertilizer. Seventy kilograms of the unused Moringa parts were blended with fifty kilograms of manure, 0.2 kilogram of Trichoderma-based product and two kilograms of superphosphate. The mixture was incubated at different intervals, including 5, 7 or 9 weeks. Next, the effects of MOF on the growth, yield, ascorbic acid content and Brix of lettuce and mustard spinach were also determined and compared with other organic fertilizers (cow manure and bio-organic fertilizer). Results of the study revealed that 25 tons per ha of MOF were significantly superior to those treated with cow manure and bio-organic fertilizer in the case of vegetable yields. Further, 7 weeks of MOF incubation was found suitable to produce an optimal yield during the various incubation period. These results suggested that the Moringa non-edible parts can make organic fertilizer and enhance growth, yield, and leafy vegetable production

EFFECTS OF SUBSTITUENTS ON CH BOND DISSOCIATION ENTHALPIES OF ENT-KAURANE DITERPENOIDS: A DFT STUDY

C-H bond dissociation enthalpies (BDEs) of seven ent-kaurane diterpenoids extracted from Croton tonkinensis Gagnep. have been investigated by using density functional theory (DFT) method. The calculations were performed at the M05-2X/6-31+G(d) level of theory. Additionally, insight into the effects of different substituents including –NH2, –OH, –NO2, –SH, –CN, –Cl, –CONH2, –CH-(CH3)2, –NHCOCH3, –OCOCH3 and –C2H5 on BDE have also been provided. The results showed that the BDE value of ent-16(S)-18-acetoxy-7b-hydroxykaur-15-one compound is lowest, being 83.5 kcal/mol. Among substituents binding at C16 position of this molecule, –NH2 has the most remarkable influence on the BDE (C-H) value. Indeed, the BDE of C16-H significantly decreases from 83.5 to 68.4 kcal/mol when replacing –CH3 group by –NH2 one at the C16 position. The obtained results may provide more information for organic synthesis of ent-kaurane based – novel antioxidant compounds