Architecture Parallel for the Renewable Energy System

This chapter present one possible evolution is the parallel topology on the high-voltage bus for the renewable energy system. The system is not connected to a chain of photovoltaic (PV) modules and the different sources renewable. This evolution retains all the advantages of this system, while increasing the level of discretization of the Maximum Power Point Tracker (MPPT). So it is no longer a chain of PV modules that works at its MPPT but each PV module. In addition, this greater discretization allows a finer control and monitoring of operation and a faster detection of defects. The main interest of parallel step-up voltage systems, in this case, lies in the fact that the use of relatively high DC voltages is possible in these architectures distributed

MÔ PHỎNG PHÂN BỐ VÀ KHẢ NĂNG CHỊU TẢI ĐỐI VỚI CHẤT LƠ LỬNG KHU VỰC ĐẦM CẦU HAI - TỈNH THỪA THIÊN-HUẾ BẰNG MÔ HÌNH TOÁN

By applying of regression methods to assimilate data for suspended particulate matter as the input data to mathematical model, the paper presents the results on the distribution and carrying capacity of suspended particulate matter in Cau Hai lagoon, Thua Thien-Hue province during the dry season (7/2013) and rainy season (10/2013). The initial simulation show that the water exchange in Cau Hai lagoon is weak in comparsion with that in Thuy Tu lagoon as well as Tam Giang lagoon, leading the distribution of suspended particulate matter to be dominated by seasonal and the suspended particulate matter from Truoi river. The overall mean concentration of suspended particulate matter is 30 g/m3 during dry season and 48 g/m3 in the rainy season. Notably, the carrying capacity of suspended particulate matter in Cau Hai lagoon is very low in the rainy season, with the remaining capacity of receiving being only 4%. Therefore, a small increase in the suspended particulate matter can result in the overload of suspended particulate matter in Cau Hai region.Ứng dụng phương pháp hồi quy đơn trong việc đồng hóa số liệu đối với chất lơ lửng làm đầu vào cho mô hình toán, bài báo đã đưa ra những kết quả về phân bố và khả năng chịu tải chất lơ lửng tại khu vực đầm Cầu Hai tỉnh Thừa Thiên-Huế trong mùa khô (7/2013) và mùa mưa (10/2013). Các kết quả mô phỏng ban đầu cho thấy, sự trao đổi nước trong khu vực đầm Cầu Hai là yếu so với sự trao đổi nước ở đầm Thủy Tú cũng như đầm Tam Giang, dẫn tới sự phân bố chất lơ lửng trong đầm chủ yếu bị chi phối theo mùa và phụ thuộc vào nguồn chất lơ lửng từ sông Truồi đưa ra. Hàm lượng chất lơ lửng trung bình toàn đầm đạt 30 g/m3 vào mùa khô và 48 g/m3 vào mùa mưa. Đáng chú ý là khả năng chịu tải chất lơ lửng đối với đầm Cầu Hai trong mùa mưa là rất thấp, khả năng tiếp nhận chỉ còn 4%. Bởi vậy chỉ cần một tác động nhỏ làm gia tăng hàm lượng chất lơ lửng vào đầm cũng dẫn đến kết quả quá tải chất lơ lửng trong khu vực đầm Cầu Hai

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

Anti–inflammatory and antioxidant properties of the ethanol extract of Clerodendrum cyrtophyllum turcz in copper sulfate‐induced inflammation in zebrafish

Oxidative stress and inflammation are commonly present in many chronic diseases. These responses are closely related to pathophysiological processes. The inflammatory process can induce oxidative stress and vice versa through the activation of multiple pathways. Therefore, agents with antioxidant and/or anti-inflammatory activities are very useful in the treatment of many pathologies. Clerodendrum cyrthophyllum Turcz, a plant belonging to the Verbenaceae family, is used in Vietnamese traditional medicine for treating migraine, hypertension, inflammation of the throat, and rheumatic arthritis. Despite its usefulness, studies on its biological properties are still scarce. In this study, ethanol extract (EE) of leaves of C. cyrtophyllum showed protective activity against CuSO4 toxicity. The protective activity was proven to relate to antioxidant and anti-inflammatory properties. EE exhibited relatively high antioxidant activity (IC50 of 16.45 µg/mL) as measured by DPPH assay. In an in vivo anti-antioxidant test, three days post fertilization (dpf) zebrafish larvae were treated with different concentrations of EE for 1 h and then exposed to 10 µM CuSO4 for 20 min to induce oxidative stress. Fluorescent probes were used to detect and quantify oxidative stress by measuring the fluorescent intensity (FI) in larvae. FI significantly decreased in the presence of EE at 5 and 20 µg/mL, demonstrating EE’s profound antioxidant effects, reducing or preventing oxidative stress from CuSO4. Moreover, the co-administration of EE also protected zebrafish larvae against oxidative damage from CuSO4 through down-regulation of hsp70 and gadd45bb expression and upregulation of sod. Due to copper accumulation in zebrafish tissues, the damage and oxidative stress were exacerbated overtime, resulting in the upregulation of genes related to inflammatory processes such as cox-2, pla2, c3a, mpo, and pro- and anti-inflammatory cytokines (il-1ß, il-8, tnf-α, and il-10, respectively). However, the association of CuSO4 with EE significantly decreased the expression of cox-2, pla2, c3a, mpo, il-8, and il-1ß. Taken together, the results suggest that EE has potent antioxidant and anti-inflammatory activities and may be useful in the treatment of various inflammatory diseases

The validation of organisational culture assessment instrument in healthcare setting: results from a cross-sectional study in Vietnam

BACKGROUND: Organisational culture (OC) has increasingly become a crucial factor in defining healthcare practice and management. However, there has been little research validating and adapting OCAI (organisational culture assessment instrument) to assess OC in healthcare settings in developing countries, including Vietnam. The purpose of this study is to validate the OCAI in a hospital setting using key psychometric tests and confirmatory factor analysis (CFA). METHODS: This is a cross-sectional study. Self-administered structured questionnaire was completed by 566 health professionals from a Vietnamese national general hospital, the General Hospital of Quang Nam province. The psychometric tests and CFA were utilized to detect internal reliability and construct validity of the instrument. RESULTS: The Cronbach\u27s alpha coefficients (alpha-reliability statistic) ranged from 0.6 to 0.8. In current culture, the coefficient was 0.80 for clan and 0.60 for adhocracy, hierarchy and market dimension, while in expected culture, the coefficient for clan, adhocracy, hierarchy, and market dimension was 0.70, 0.70, 0.70 and 0.60, respectively. The CFA indicated that most factor loading coefficients were of moderate values ranging from 0.30 to 0.60 in both current and expected culture model. These models are of marginal good fit. CONCLUSIONS: The study findings suggest that the OCAI be of fairly good reliability and construct validity in measuring four types of organisational culture in healthcare setting in resource-constrained countries such as Vietnam. This result is a first step towards developing a valid Vietnamese version of the OCAI which can also provide a strong case for future research in the field of measuring and managing organisational culture

Radicular cyst in a primary molar following pulp therapy with gutta percha : a case report and literature review

A radicular cyst (RC) in deciduous dentition is relatively rare. This clinical report presents a case of RC that condition derived from a primary molar undergone an endodontic treatment with gutta-percha approximately one year ago. In addition, we also considered whether intracanal medicaments and gutta-percha filling material related to the formation and development of the cyst or not

SOME RESULTS OF STUDY ON PRESENT SITUATION OF HOUSEHOLD SOLID WASTE IN HANOI, VIETNAM

This paper presents some results on the study of Solid waste generated by households (hereinafter referred to as HSW) in Hanoi city. Compositions of the waste generated from three typical communities and their relationship with family life-style of each community were investigated. Differences among compositions of HSW of three resident groups of different incomes, lifestyles were analyzed. Based on the study results, some measures for better management of HSW and maximum reuse and recycle of HSW were proposed. By this way, the amount of HSW transported to landfill could be reduced and stabilization phase of landfill sites could be shortened

Study on the effect of carbon black, carbon nanotube on the properties of rubber blend acrylonitrile butadiene rubber (NBR)/polyvinyl chloride (PVC)

The effects of carbon nanotube (CNT) in combination with carbon black (CB) on the properties of acrylonitrile butadiene rubber (NBR)/polyvinyl chloride (PVC) (70/30) were investigated. The results reveal that the maximal tensile strength of the rubber blend was obtained by the fillers ratio of CB:CNT = 39:1. At this filler ratio, the thermal stability and heat conductivity of the rubber blend were also significantly improved. The analysis of FE-SEM images and DMA diagram indicate that the dispersion of filler as well as the interaction between fillers and rubber matrix was improved by the incorporation of CNT. Keywords. NBR/PVC blends, carbon nanotube (CNT), carbon black (CB), nanocomposites

CSA: Thực hành nông nghiệp thông minh với khí hậu ở Việt Nam

During the last five years, Vietnam has been one of the countries most affected by climate change. Severe typhoons, flooding, cold spells, salinity intrusion, and drought have affected agriculture production across the country, from upland to lowland regions. Fortunately for Vietnam, continuous work in developing climate-smart agriculture has been occurring in research organizations and among innovative farmers and entrepreneurs. Application of various CSA practices and technologies to adapt to the impact of climate change in agriculture production have been expanding. However, there is a need to accelerate the scaling process of these practices and technologies in order to ensure growth of agriculture production and food security, increase income of farmers, make farming climate resilient, and contribute to global climate change mitigation. This book aims to provide basic information to researchers, managers, and technicians and extentionists at different levels on what CSA practices and technologies can be up scaled in different locations in Vietnam