Thinh Van Nguyen

Heavy metal contamination of soil and sediment in estuaries warrants study because a healthy estuarine environment, including healthy soil, is important in order to achieve ecological balance and good aquaculture production. The Ba Lat estuary of the Red River is the largest estuary in northern Vietnam and is employed in various land uses. However, the heavy metal contamination of its soil has not yet been reported. The following research was conducted to clarify contamination levels, supply sou

The effect of environmental variables on the presence and abundance of tree species in a tropical lowland undisturbed limestone and non-limestone forest in Ben En National Park, Vietnam was investigated. The relationships between 13 environmental variables and 29 tree species with a DBH <TEX>${\geq}10cm$</TEX>, as well as between six 6 physical variables with 26 species of seedling and sapling communities were assessed by canonical correspondence analysis (CCA). Data concerning all tree species

A series of arsenic remediation tests were conducted using a washing method with biodegradable organic acids, including oxalic, citric and ascorbic acids. Approximately 80% of the arsenic in one sample was removed under the effect of the ascorbic and oxalic acid combination, which was roughly twice higher than the effectiveness of the ascorbic and citric acid combination under the same conditions. The soils treated using biodegradable acids had low remaining concentrations of arsenic that are pr

We examined ionoregulatory characteristics of two species of characiform fish and two species of cichlids that are not native to the Rio Negro, an extremely ion-poor, acidic tributary of the Amazon River, in order to gain insight into the origin of the specializations possessed by Rio Negro fish. The two characiform species examined, Congo tetras (Phenacogrammus interruptus) and black neon tetras (Hyphessobrycon herbertaxelrodi), had high-affinity/high-capacity transporters that produce high rat

The contamination of agricultural soils by the toxic trace metals arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu) and zinc (Zn) was investigated in an industrial district in Vietnam. In this district, irrigation agriculture is conducted via channels; additionally, there are two industrial parks on nearby agricultural land. The purpose of the study was to clarify the magnitude and spatial distribution the trace metal concentrations, the source of the trace metals, the difference

The Cuu Long basin is equiped with infrastructures and processing facilities serving for large-scale crude oil drilling and production operations. However, most of resevoirs in this area are now depleted, it means that they have reached their peaks and started to undergo decreasing productivity, which lead to a noticable excess capicity of equipment. In order to benefit from those declined oil fieds and maximize performance of platforms, solutions to connect marginal fields have been suggested a

In offshore production of oil and gas, transporting products by subsea pipeline always has potential risks affecting the efficiency of the transportation process. For the Diamond oilfield, the process of gathering products and transportation is carried out according to a closed scheme in which the exploited products are preliminarily treated. The separated oil is transported to FPSO Ruby - II while the separated gas passed through the air compressor to increase pressure and then used for gaslift

Two warty newt species, Paramesotriton deloustali and P. guangxiensis, are known from Vietnam for a long time. However, the taxonomic status of some Vietnamese populations was recently clarified. In this study, we conducted surveys in northern Vietnam to collect samples for molecular and morphological analyses of Paramesotriton species. Our phylogenetic analyses based on two mitochondrial genes (16S and ND2) agreed well with previous findings that populations from Bac Kan, Ha Giang, Lao Cai, Son

Abstract Every year, many typhoons make landfall in Japan causing disasters on mountain slopes across the country. Rainfall induced landslides in Japan mostly occur at shallow depths. Developing simple models of rainfall-induced landslides provides a practical alternative to finite element methods in large-scale landslide modelling and prediction. Therefore, authors previously developed a simple method to calculate the advance of the wetting front into fine sand slopes subjected rainfall. Howeve