IMPACTS OF BIOMASS BURNING AND LARGE-SCALE TRANSPORT ON THE SOUTHEAST ASIAN HAZE

Department of Urban and Environmental Engineering (Environmental Science and Engineering)Biomass burning has significant impacts on regional air quality and climate in Southeast Asia. This study examines the impacts of biomass burning on the large-scale transport of aerosols and haze events using observational analysis and numerical model simulations. The spatiotemporal variation of observed aerosols shows significant correlations, positively with the emission induced by fire and negatively with the removal by precipitation both in seasonal and inter-annual timescale. Particularly, the variation of aerosol optical depth (AOD) retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS) is primarily affected by El Niño Southern Oscillation (ENSO), leading to a substantial year-to-year variation. The aerosol reanalysis data from the Modern-Era Retrospective analysis for Research and Applications 2 (MERRA-2) reveals that the aerosols emitted from combustion such as organic carbon and sulfate are the main contributors to the total AOD variation in this region. Organic carbon accounts for over 60 % of total AOD amounts, being highly correlated with the biomass burning, while sulfate also serves as a significant source for the background aerosol concentration. The impacts of aerosols on meteorology and the local air quality have been further investigated using the Weather Research and Forecasting/Chemistry (WRF-Chem) model simulations for June 2013 and September 2015. Overall, the model simulation can capture the most of observed spatial and temporal variations of aerosol appeared in MODIS and MERRA-2, although it tends to underestimate AOD for the both tested cases. The model sensitivity experiments show that both aerosol direct and indirect effects have significant impacts on meteorology and local air quality. The direct impact of aerosols tends to reduce the incoming shortwave radiation at the surface, thereby decreasing surface temperature and the planetary boundary layer (PBL) height. Because of decreasing the PBL height and stabilizing lower atmosphere, the aerosol direct effect tends to increase near-surface concentration of atmospheric trace gases such as NOx, CO and O3. The indirect impact of aerosols also contributes to decrease the shortwave radiation through enhanced activation of cloud condensation nuclei particularly over the ocean. The near-surface concentration of trace gases tends to increase also by the aerosol indirect impact near the emission source except O3, which actually decreases. In case of AOD and PM2.5, both aerosol effects have significant impacts in which the direct effect increases AOD and PM2.5 whereas aerosol indirect effect decreases AOD and PM2.5. Although the direct and indirect feedbacks on aerosol mass concentrations are subject to uncertainties, this work demonstrates the significance role of aerosol feedback for real-time air quality forecasting under haze conditions.ope

THE DIVERSITY OF YELLOW CAMELLIAS IN THE CENTRAL HIGHLANDS, VIETNAM

The Central Highlands (Tây Nguyên) is a center of yellow camellia diversity in Vietnam and the world. The Central Highlands contains 18 of Vietnam’s yellow camellia species, accounting for 37% of yellow camellia species in Vietnam and 28% of yellow camellia species worldwide. Moreover, all 18 yellow camellia species in the Central Highlands are endemic to Vietnam. The camellias of the Central Highlands belong to nine sections, accounting for 75% of the world. The yellow colors occur in three groups: pale yellow, yellow, and yellow with compound colors. The yellow camellia distribution is dispersed at 500–1600 m elevation in evergreen broadleaf forests and mixed wood-bamboo forests

Numerical and Experimental Study on the Grinding Performance of Ti-Based Super-Alloy

The experiments of the surface grinding of Ti-6Al-4V grade 5 alloy (Ti-64) with a resin-bonded cubic Boron Nitride (cBN) grinding wheel are performed in this research to estimate the influence of cutting parameters named workpiece infeed speed, Depth of Cut (DOC), cooling condition on the grinding force, force ratio, and specific energy. A finite element simulation model of single-grain grinding of Ti-64 is also implemented in order to predict the values of grinding forces and temperature. The experimental results show that an increase of workpiece infeed speed creates higher intensified cutting forces than the DOC. The grinding experiments under wet conditions present slightly lower tangential forces, force ratio, and specific energy than those in dry grinding. The simulation outcomes exhibit that the relative deviation of simulated and experimental forces is in the range of 1-15%. The increase in feed rate considerably reduces grinding temperature, while enhancement of DOC elevates the heat generation in the cutting zone

CAMELLIA SPHAMII (THEACEAE, SECT. PIQUETIA), A NEW TAXON OF YELLOW FLOWER FROM LANGBIANG BIOSPHERE RESERVE, VIETNAM

Camellia sphamii is described and illustrated as a new species of section Piquetia from Hamasin village, D’ran town, Don Duong district, Lam Dong province, Vietnam. C. sphamii is similar to C. proensis (Quach, Luong et al., 2021) but differs from it in several morphological features: mature leaves cordate at base, young leaves purple; pericarp 7–8 mm thick with dense hair on the outer surface, flower buds ovate, ferruginous; sepals 5, hemisphere, concave, finely hairy on the outer surface, sparsely hairy on the inside, petals 7, finely hairy on the outer surface, with translucent margin, concave; style 5, ½ basally united; capsule 5 locular. Information on its phenology, distribution, ecology, and conservation status is also provided

Cancer Screening Practices Among Chinese and Vietnamese in the Greater Houston Area

National data on Asian Americans indicate that compared to other groups in the US, cancer incidence and prevalence is relatively lower (Miller, Kolonel et al. 1996; American Cancer Society 2006). However, when the data is examined further based on specific Asian subgroups and for specific cancers, Asian Americans bear a disproportionate burden for cancers of infectious origin, such as cervical, liver, and stomach cancer (Chen 2005). Furthermore, Asian Americans are also experiencing increasing rates of cancers associated with “Westernization,” such as breast and prostate cancer (Kolonel, Yoshizawa et al. 1988; Whittemore, Kolonel et al. 1995; Ziegler, Hoover et al. 1996). Early detection and screening are among the frontline strategies in cancer control, yet Asian American and Pacific Islanders have the lowest cancer screening rates of all ethnic groups in the US (American Cancer Society 2006). The Asian American Health Needs Assessment (AsANA) project was designed to collect data on the rapidly growing Asian American community in the Greater Houston area. The AsANA project included a telephone survey to over 800 randomly selected households in the Chinese and Vietnamese communities, two of the largest Asian American subgroups in Texas. Included in the telephone interview were questions regarding cancer screening practices. This article describes the reported screening practices among the surveyed populations and discusses the implications for developing targeted programs that can address cancer screening disparities in this community

Multisensor Data Fusion for Reliable Obstacle Avoidance

In this work, we propose a new approach that combines data from multiple sensors for reliable obstacle avoidance. The sensors include two depth cameras and a LiDAR arranged so that they can capture the whole 3D area in front of the robot and a 2D slide around it. To fuse the data from these sensors, we first use an external camera as a reference to combine data from two depth cameras. A projection technique is then introduced to convert the 3D point cloud data of the cameras to its 2D correspondence. An obstacle avoidance algorithm is then developed based on the dynamic window approach. A number of experiments have been conducted to evaluate our proposed approach. The results show that the robot can effectively avoid static and dynamic obstacles of different shapes and sizes in different environments.Comment: In the 11th International Conference on Control, Automation and Information Sciences (ICCAIS 2022), Hanoi, Vietna

FACTORS INFLUENCING TOURIST SATISFACTION WITH AGRITOURISM IN THE MEKONG DELTA, VIETNAM

The Mekong Delta, Vietnam possesses great potential and advantages for developing agritourism. To ensure the sustainable development of agritourism, enhance service quality, and improve tourist satisfaction are essential. This study aims to identify the factors influencing tourist satisfaction with agritourism in the Mekong Delta. Data were collected using a quota sampling method, with a sample size of 228 tourists who had visited and experienced agritourism in the Mekong Delta, Vietnam. A mixed-method approach combining qualitative and quantitative research was used to test research hypotheses. By applying structural equation modeling (SEM), the study demonstrated that local culture, natural landscape, novelty, assurance, tourism human resources, and perceived value positively influenced tourist satisfaction with agritourism in the Mekong Delta. Among these factors, the natural landscape had the most impact on tourist satisfaction with agritourism in the Mekong Delt

Two new additions to the flora of Vietnam

Among the studied specimens collected from Son Tra Nature Reserve, Vietnam, two new taxa: Oxalis barrelieri L. (Oxalidaceae) and Glochidion acuminatum var. siamense Airy Shaw (Phyllanthaceae) which forms new records to the flora of Vietnam. Taxonomic description, habitat, distribution and uses, and color photographs of both taxa are provided

Reduced Need of Infiltration Anesthesia Accompanied With Other Positive Outcomes in Diode Laser Application for Frenectomy in Children

Introduction: The abnormal maxillary labial frenum is common in children during the primary or mixed dentition stage. A conventional surgery for this abnormality usually requires infiltration anesthesia which leads to fear in children and consequent noncooperation during the surgery. The aim of present study was to evaluate the reduction in the need of infiltration anesthesia, intraoperative bleeding control and postoperative pain and wound healing in children when using the diode laser for abnormal labial frenum in the maxilla.Methods: The present study was carried out among 30 children attending the Hanoi Medical University, Vietnam. A Diode Laser with 810 nm wavelength and power of 0.8 W was used for frenectomy.Results: The proportion of procedures without any need of infiltration anesthesia was 70%, while 93.34% of children demonstrated positive and very positive behavior. Proportion of indolence on the first day after surgery was 83.3%. While 83.3% of children did not take any analgesics, not a single child complained of any pain 3 days after surgery.Conclusion: Our results indicated that the use of diode laser showed several benefits in maxillary labial frenectomy in children. These included reducing the need of infiltration anesthesia, increasing the children’s cooperation as well as decreasing the postoperative pain