Search Results (6)

Accurate estimation of emissions of greenhouse gases (GHGs) is required for making effective climate change mitigation policies at the national level. Among major sources, municipal solid waste (MSW) is an important source of GHGs, such as methane (CH₄), generated during the anaerobic decomposition of organic matter. In Viet Nam, the emissions of GHGs are not well quantified, in particular from the MSW management system. In this study, we estimated emissions of GHGs from the MSW management system of Ho Chi Minh City (HCMC), considering the current waste management practices. In HCMC, landfilling has been a common practice of solid waste management. About 85 percent of the total MSW generated in the city has been landfilled at two landfill sites. Our estimates show that landfilling was the significant source of GHGs in HCMC, with a net contribution of 781.05 kg CO₂-equivalent (CO₂-eq.) per tonne of MSW landfilled. From the whole MSW management system, the direct GHG emission was 768.61 (kg CO₂-eq. per tonne of MSW) with avoided emissions of 72.47 (kg CO₂-eq. per tonne of MSW) through composting and recycling of MSW. The net GHG emission from the MSW management system was 696.14 kg CO₂-eq. per tonne of MSW (≈1.665 million tonnes of CO₂-eq. per year). The GHG emission data of this study may be useful to policymakers for making effective climate change mitigation policies. Full article

This paper seeks to uncover the impact of negative rainfall shocks on household social network relationships. I leverage the uncertainty generated from fluctuating long-term rainfall patterns across India, to estimate the impact of heightened climate risks on investments in social network relationships. In so doing, I attempt to disentangle the “direct” and “adaptive” impacts of climate shocks on social network relationships. I found that households that experience higher than average negative rainfall shocks (lower than average rainfall levels over the long term) tend to invest more in family–caste and vertical or linked network relationships. These network relationships were also found to be associated with greater access to financial credit, credit sourced specifically from family members, higher reported collaboration, more diversified businesses, and the use of private irrigation technologies, all of which are key to mitigating the negative impacts of climate shocks. Unlike past research, these results suggest that households’ decisions to invest in social networks may be an adaptive response to higher climate risk. In terms of policy implications, these results highlight the importance of strengthening and supporting family-based and linked networks (such as links to local governmental agencies and extension services) in the face of higher climate risks. Full article

This research discusses the role of Web 4.0 and 5.0 devices on the commercial sustainability for tourism in Ho Chi Minh City (HCMC), Vietnam. The study adopts a tourist perspective regarding the future implementation of Web 4.0 and 5.0 devices, focusing on the service quality of various tourism-associated services and assessing, in return, the extent to which the overall satisfaction and long-term patronage of tourists is affected. Usually, researchers conduct this test in various popular establishments where devices are intended for experimental use and tourists are supposed to have previous exposure to them, so that their perceptual thinking regarding the service quality of these devices can be studied. The tourists act as respondents for various establishments. We also asked subjective questions in a short interview to 10 professionals working in these establishments, which helped us in the quantitative survey process. As a mixed method study, it has covered both quantitative and qualitative aspects of the items and provided a holistic result. The results indicated that Web 4.0 and 5.0, along with the service quality offered by personnel working in the establishments, showed significant variance in holistic service evaluation for tourist satisfaction and loyalty. Very few service quality factors had a distinct variance in the output. After using a regression analysis for Web 4.0 and 5.0 devices and service quality, we found that Web 4.0 and 5.0 showed insignificant negative results. This study contributes to the incremental research on Web 1.0 to 5.0, specifically detailing how it affects tourists’ satisfaction and patronage. Moreover, from a management point of view, this study can help solve the financial riddle of various establishments in HCMCs tourism ecosystem for optimum fund management and better productivity. Full article

Photonic crystals (PhC) are spatially ordered structures with lattice parameters comparable to the wavelength of propagating light. Their geometrical and refractive index features lead to an energy band structure for photons, which may allow or forbid the propagation of electromagnetic waves in a limited frequency range. These unique properties have attracted much attention for both theoretical and applied research. Devices such as high-reflection omnidirectional mirrors, low-loss waveguides, and high- and low-reflection coatings have been demonstrated, and several application areas have been explored, from optical communications and color displays to energy harvest and sensors. In this latter area, photonic crystal fibers (PCF) have proven to be very suitable for the development of highly performing sensors, but one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) PhCs have been successfully employed, too. The working principle of most PhC sensors is based on the fact that any physical phenomenon which affects the periodicity and the refractive index of the PhC structure induces changes in the intensity and spectral characteristics of the reflected, transmitted or diffracted light; thus, optical measurements allow one to sense, for instance, temperature, pressure, strain, chemical parameters, like pH and ionic strength, and the presence of chemical or biological elements. In the present article, after a brief general introduction, we present a review of the state of the art of PhC sensors, with particular reference to our own results in the field of mechanochromic sensors. We believe that PhC sensors based on changes of structural color and mechanochromic effect are able to provide a promising, technologically simple, low-cost platform for further developing devices and functionalities. Full article

To determine the effectivity of bacteriophages in controlling the mass mortality of striped catfish (Pangasianodon hypophthalmus) due to infections caused by Aeromonas spp. in Vietnamese fish farms, bacteriophages against pathogenic Aeromonas hydrophila were isolated. A. hydrophila-phage 2 and A. hydrophila-phage 5 were successfully isolated from water samples from the Saigon River of Ho Chi Minh City, Vietnam. These phages, belonging to the Myoviridae family, were found to have broad activity spectra, even against the tested multiple-antibiotic-resistant Aeromonas isolates. The latent periods and burst size of phage 2 were 10 min and 213 PFU per infected host cell, respectively. The bacteriophages proved to be effective in inhibiting the growth of the Aeromonas spp. under laboratory conditions. Phage treatments applied to the pathogenic strains during infestation of catfish resulted in a significant improvement in the survival rates of the tested fishes, with up to 100% survival with MOI 100, compared to 18.3% survival observed in control experiments. These findings illustrate the potential for using phages as an effective bio-treatment method to control Motile Aeromonas Septicemia (MAS) in fish farms. This study provides further evidence towards the use of bacteriophages to effectively control disease in aquaculture operations. Full article

Water saving is a key issue in rapidly developing countries, such as Vietnam, that face various water resource management challenges. This study investigated water-use patterns in a hotel in Ho Chi Minh City in Vietnam. It aimed to quantify the efficiency of water-saving devices through modeling toilet and shower usage patterns, including water consumption. The shift in hourly consumption of cold and hot water was also identified. Analysis revealed that, on average, a full toilet flush occurs 3.3 times/day, a half flush 3.0 times/day, water consumption due to shower usage is 48.1 L/day, showering time is 7.3 min/day and the shower water temperature is 37.7 °C. Shifting levels of hot and cold water use revealed high activity in the morning time and that there are two peaks, occurring in the morning and at night. Full article