Evaluation of municipal waste management options by circular prevention tools to give better ways for sustainable transition – A case study of Hanoi

The transition management approach can help to improve municipal solid waste management in individual cities and city regions. The obsolete technological solutions of waste management cannot support efficient and sustainable urban waste management processes. We would like to present a possible solution to development of the municipal solid waste management system in a high population density megapolis, Hanoi (Vietnam). We examined the development opportunities at three strategic levels (governmental, enterprise and personal levels). We have analyzed the system at strategic, tactical, operational and reflexive levels also, using a transition matrix. Five development aspects and technological directions have been identified, and all of them could be applied at the three decision levels. We came to the conclusion that intervention is needed at all three levels. Based on our results, we have made proposals for the transformation of Hanoi solid waste management structure in the overall organizational structure

A STUDY ON POWER OUTPUT OF HORIZONTAL-AXIS WIND TURBINES UNDER RAIN

The power of the wind turbine are significantly affected by the air conditions of the operating environment. Rain is a widespread phenomenon in many parts of the world especially in Vietnam, so exploring its effect on the power of wind turbines will provide valuable insights into the design of a new wind tower. In this paper, a method and a model is developed to estimate the effect of precipitation by simulating the actual physical processes of the rain drops forming on the surface of the blades of horizontal-axis wind turbines (HAWT), thereby determining optimal wetness, then power and performance respectively. Consequently, it makes a contribution to operation and control strategies for horizontal-axis wind turbines

A secure image steganography based on JND model

Minimizing distortion produced by embedding process is very important to improve the security of hidden message and maintain the high visual quality of stego images. To achieve these objectives, an effective strategy is to perform pixel selection which is well-known as a channel selection rule. In this approach, a pixel associated with the smallest image degradation is chosen to carry secret bits. From these facts, in this paper, a new secure channel selection rule for digital images in spatial domain is designed and proposed. In this new approach, the modified matrix embedding method is utilized as data hiding method because it introduces more than one embedding change to be performed. This enables us to select a suitable pixel to embed message bits with less degradation yielded in a stego-image. In pixel selection of the proposed method, a just noticeable difference value and gradient value of a considering pixel are employed together. The experimental results (which were conducted on 10,000 uncompressed images) indicate that stego images of the proposed approach achieve a higher perceptual quality and security than those of the stego-images created by the previous approaches

A method to analyze power output of vertical-axis wind turbines under rain

A method to analyze effect power output of a vertical axis wind turbine under rain is proposed. The rain had the effect of increasing the drag, slowing the rotational speed of the wind turbine and decreasing the power and performance. More and more ambitious projects for wind turbine production being set on many where on Vietnam, it is necessary to understand all the factors, especially by weather changes, that might affect wind power production. In this research, we lay out a model to estimate the effect of rainfall by simulating the actual physical processes of the rain drops forming on the surface of the blades of a vertical-axis wind turbine (VAWT), thereby determining optimal wetness, then power and performance respectively. This could have an effect on the control strategy necessary for designing and controlling wind turbine

Investigation of botulism in free-range duck farming in the Mekong Delta, Vietnam

Background: One of the most common diseases in free-range ducks in the Mekong Delta is botulism. Botulism is a poultry disease caused by botulinum exotoxin of Clostridium botulinum. Aim: To evaluate the prevalence of botulism in free-range ducks in the Mekong Delta and the risk of infection by determining the presence of C. botulinum in the farming environment. Methods: Research was carried out on 200 duck flocks with 187,050 individuals raised freely in the fields in the provinces of the Mekong Delta, including An Giang, Can Tho, Hau Giang, and Kien Giang. The ducks were diagnosed with botulism based on clinical symptoms. To demonstrate the presence of botulinum neurotoxins and identify serotype, samples of serum and/or gut were analyzed by mouse bioassay. Samples of soil (n = 600), water (n = 600), crabs (n = 216), and snails (n = 400) were taken from the grazing regions for C. botulinum analysis by PCR assay. Results: There were 1.19% (2,235/187,050) free-range ducks in the Mekong Delta positive for botulism. Clinical symptoms of botulism including limberneck, drooping eyelids–enlarged pupils, and leg paralysis were prevalent across free-range ducks, with the frequency of 87.92% (1,965/2,235), 90.07% (2,013/2,235), and 79.78% (1,783/2,235), respectively. The lesions of pulmonary edema–hemorrhage, hemorrhagic liver, and gas-producing intestines were common, accounting for 86.19% (362/420), 95.48% (401/420), and 92.14% (387/420), respectively. Botulin toxin type C was found in a considerable number of serum samples, accounting for 40.48% (51/126). Meanwhile, the percentage of serum samples containing botulin toxin types E and D was 28.57% (36/126) and 25.40% (32/126), respectively. Clostridium botulinum was detected in the farming environment specifically 17.5% (105/600) in soil, 19.67% (118/600) in water, 8.33% (18/216) in crabs, and 3.00% (12/400) in snails. Conclusion: The free-range ducks in the Mekong Delta were at high risk of botulism because of the latent presence of C. botulinum in the farming environment

The Influence of Investor's Characteristics on the Perception About the Selling Price of Luxury Apartments in Hanoi

This research was conducted to investigate the impact of investor's characteristics on the perception about the selling price of luxury apartments in Hanoi, Vietnam. Data were collected through a survey with 458 real estate employees from Hanoi. With this data, we have used descriptive statistics, Cronbach's Alpha to determine the level of impact of the independent variable on the dependent variable, i.e. the perception about the selling price of luxury apartments. The results showed that the determinant is the investor's characteristics which have positive relationships with the perception about the selling price of luxury apartments in Hanoi. Based on this finding, this paper gives several recommendations for improvement the perception about the selling price of luxury apartments in Hanoi. Keywords: the perception about the selling price of luxury apartme, investor's characteristics, real estate JEL codes: G12, G13, G14, L80, L85 DOI: 10.7176/EJBM/12-9-06 Publication date:March 31st 202

Diversity of plant-parasitic nematodes on medicinal plants in Melinh station for biodiversity, Vinh Phuc Province, Vietnam

Plant-parasitic nematodes are known as one of the most important pests attacking various plants in the world, and investigating the nematode component is very essential for management of this pest and prevent damage to plants in general. Our survey of plant-parasitic nematodes on medicinal plants in Melinh Station for Biodiversity, a place for conservation of precious plants and animals in Vietnam, identified ten species that belong to nine genera, five families, and two orders of plant-parasitic nematodes parasitizing six medicinal plants. Excoecaria cochinchinensis was parasitized by the highest number of nematode genera (5 genera, including Xiphinema, Discocriconemella, Meloidogyne, Helicotylenchus, and Hemicriconemoides), while Hymenocallis littoralis was associated with the highest number of plant-parasitic nematodes (2060 nematodes/250g soil). The results also showed that Discocriconemella limitanea was found to be a dominant species with the highest number of individuals on 6 medicinal plants, and the genus Helicotylenchus had the highest frequency of appearance (5/6 plants or 83.3%). These nematodes caused symptoms such as yellowing leaves, root galls, and root lesions, which directly affect the quality and yield of medicinal plants. Based on the results, this study showed that plant-parasitic nematodes are a potential threat to the cultivation of medicinal plants in Melinh Station for Biodiversity, and thus, control measures should be applied to ensure sustainable cultivation of medicinal plants in this place

A Low Cost and Low Power Consumption Automatic Water Meter Reading System: Hardware Investigation and Network Design

This paper presents a low power consumption and low cost automatic data collection network for water meter application. Based on transmission performance and power consumption, several low cost sub-GHz wireless transceivers are analyzed and compared, and consequently a suitable hardware is chosen. The associated network protocol stack is also examined. To construct the automatic collecting data mechanism, we consider a cluster based wireless sensor network (WSN) where routers and a GPRS gateway are used to link each cluster to a data collection center. Advantages of this proposed configuration are the simple implementation, low cost and low power consumption. By using the Monte Carlo simulation technique, packet delivery ratio and power consumption for different topologies are investigated. Based on obtained results, the optimum network topology for automatic water meter reading in a typical urban environment is finally proposed

Developing E-Commerce web-site using Zend Framework and MySQL database

This thesis concentrates on developing an E-commerce website using Zend framework and MySQL database. Basically, a web development consists of 5 stages: graphic user interface(GUI) design, database design, back-end development, front-end development and search engine optimization (SEO) but only graphic user interface design, database design and back-end developing using Zend framework are focused in this thesis. The outcome of this thesis is the E-commerce website, www.mocaymart.com. The main methodology in this thesis is qualitative research, which mainly conducts various interviews for requirements collection and analysis. Furthermore, constructive research that is designed to solve problems in the real world is also ultilized. As a conclusion, the web owner satisfies with www.mocaymart.com and this website is evalu-ated as the key factor in their start-up plan