Growth and morphological responses of Halophila beccarii to low salinity

Halophila beccarii Ascherson is classified as a threatened seagrass species by IUCN because of the reductive tendency of ​​its distribution area. This seagrass is considered a euryhaline species adapted to a wide range of salinities from freshwater and brackish water to marine water. Previous studies showed that the species tends to grow better under low salinity; however, its optimum salinity has not been determined. In Vietnam, H. beccarii grows in habitats with low salinity (0–20 ppt). The results show that salinity affects the growth, survival rate, shoot density, biomass, and morphological characteristics of the grass. The leaf dimension is more prolonged and broader; the petiole and shoot length are longer at 10 ppt salinity. In contrast, both the number of shoots and biomass peak at 5 ppt and decrease at lower and higher salinities. The study reveals that H. beccarii can grow better under mesohaline conditions than freshwater and hypersaline conditions with an optimum salinity at 5–10 ppt. These findings would explain the species’ distribution dynamics in coastal environments and be helpful information for conserving the seagrass populations in habitats with fluctuating salinity as coastal lagoons in Central Vietnam

MODELING USING 2-D AREAS OF IDEAL CROSS-POINT REGIONS FOR LOSSLESS IMAGES COMPRESSION

This paper presents 2-D areas of ideal cross-point regions which are the new part in the theory of cross-point regions. Actually for using cross-point regions we need an algorithm for determining cross-point maps; this takes a long time and a big space for storing these maps, and brings about not high compression ratio when using one dimensional cross-point regions because many coordinates of data points need to be saved for decoding. When these 2-D areas are used, the scheme of 2-DICRIC (2-D Ideal Cross-point Regions for lossless Image Compression) for losslessly encoding and decoding images with the optimization of probability of cross points which are neighbor to the points of grey levels 2n is improved to get higher compression ratio. The base idea of this method is the effect of Gray coding on cross points, and there are many cross-point regions. Before Gray coding data sets of cross points are determined, they are called the ideal cross point regions (ICRs). After Gray coding these regions always contain only 1 bits or 0 bits depending on the number of bit plane after the operation of bit plane decomposition. This is the characteristic of images, the data do not change much in a specific area, especially in medical images which have many regions with the approximate grey levels. So, the way to determine 2-D areas of cross-point regions so that the cross-point maps are small is important for the theory. The theory with these 2-D areas has important effects on the compression ratio when encoding and decoding processes of lossless image compression for data transmission are proceeded

INFLUENCE OF SYNTHESIS FACTORS ON PROPERTIES OF GEOPOLYMERS BASED ON RED MUD AND RICE HUSK ASH

In this paper, the effect of mixing ratio of raw materials, curing temperature and time on geopolymerization between red mud and rice husk ash were investigated. The results showed that the optimum conditions were SiO2/Al2O3 ratio of 4 and Na2O/Al2O3 ratio of 2.0, curing temperature of 100oC and curing time of 24 hours. The compressive strength, bulk density, total shrinkage of the obtained product were 22.8 MPa, 2.39 g.cm-3, 15%, respectively that met requirement of unsintered bricks using for construction

A STUDY ON THE SYNTHESIS OF MgAl2O4 SPINEL BY STARCH ASSISTED SOL-GEL PROCESS

In this paper, the synthesis of ceramic spinel MgAl2O4 by starch assisted sol - gel process is presented. The gel mixture was prepared by using Mg(NO3)2.6H2O, Al(NO3)3.9H2O as precursors and starch as a gel agent. The study focused on relevant components of gel mixture and the calcinating temperature. The results showed that suitable molar proportion of Mg2+/Al3+; starch/(Mg2+ + Al3+) and H2O/starch were 0.5, 0.4 and 60, respectively. The calcination at               1100 oC for 60 minutes was suitable for forming phase of spinel. The product was a single phase of spinel MgAl2O4 with excellent crystallinity and uniform size in the range of 300 to 400 nm

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

FABRICATION OF CARBON NANOTUBES FROM LIQUEFIED PETROLEUM GAS BY CHEMICAL VAPOUR DEPOSITION

This paper presents the fabrication of carbon nanotubes from liquefied petroleum gas (LPG) by chemical vapour deposition with Fe/SiO2 as a catalyst. The morphology and tube diameter of the carbon nanotubes are dependent on the flow rates of H2 and LPG, and the crystal growth temperature. The obtained CNTs were characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), scanning transmission electron microscope (STEM), and Brunauer-Emmett-Teller surface area analyses. The results indicate that the suitable conditions for forming the nano-sized tubes are 700 °C for 2 hours with the H2 and LPG flow rate of 140 mL·min–1 and 80  mL·min–1, respectively. The multi-walled structures with long, less defective tubes and identical external diameter of 52 nm and BET surface area of 93 m2·g–1 are obtained

NGHIÊN CỨU MỘT SỐ ĐẶC TRƯNG HÓA LÝ CỦA BÙN ĐỎ TÂN RAI, LÂM ĐỒNG

In the present paper, physico-chemical characterizations including chemical composition, crystal phase composition, particle size distribution, particle morphology, physico-chemical processes during the sintering, functional groups on the surface of Tanrai red mud (Lamdong, Vietnam) were investigated. Tanrai red mud was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), lazer diffraction, thermogravimetry and differential scanning calorimetry (TG-DSC), scanning electron microscope (SEM), transmission electron microscope (TEM) and Fourier-transform infrared spectroscopy (FT-IR) analyses. The results showed that main crystal phases of red mud were hematite (Fe2O3), goethite (FeO(OH)) and gibbsite (Al(OH)3). The amounts of Fe2O3 (46,7%), Al2O3 (19,1%), Na2O (4,4%), TiO2 (5,9%) in red mud were rather high that were suitable for manufacturing iron and steel, unsintered bricks, sintered bricks, and recovering TiO2. High alkaline amount (pH > 11) of red mud with small particle size is a factor strongly concerning water and air polutions.Bài báo trình bày một số đặc trưng hóa lý: thành phần hóa học, thành phần pha tinh thể, phân bố cấp hạt, hình thái và kích thước hạt, các quá trình hóa lý xảy ra khi nung, các nhóm chức đặc trưng của bùn đỏ Tân Rai, Lâm Đồng, Việt Nam. Các đặc trưng của bùn đỏ được xác định bằng các phương pháp nhiễu xạ tia X (XRD), huỳnh quang tia X (XRF), tán xạ laze, phân tích nhiệt (TG-DSC), hiển vi điện tử quét (SEM), hiển vi điện tử truyền qua (TEM), phổ hồng ngoại (FT-IR). Kết quả cho thấy: thành phần pha tinh thể của bùn đỏ chủ yếu là hematite (Fe2O3), goethite (FeO(OH)) và gibbsite (Al(OH)3). Hàm lượng các oxit Fe2O3 (46,7%), Al2O3 (19,1%), Na2O (4,4%), TiO2 (5,9%) khá cao, có thể sử dụng bùn đỏ làm nguyên liệu để sản xuất sắt thép, gạch không nung, gạch nung, thu hồi TiO2. Bùn đỏ có môi trường kiềm mạnh (pH > 11), cấp hạt nhỏ,  có khả năng gây ô nhiễm môi trường nước và không khí

Oxidation of carbon nanotubes using for Cu(II) adsorption from aqueous solution

Carbon nanotubes (CNTs) synthesized by chemical vapour deposition without using hydrogen were oxidized with 0.1 M potassium permanganate at 40oC for 2 hours and exhibited high CuII adsorption capacity from aqueous solution. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM) and nitrogen adsorption/desorption isotherms were used to characterize the oxidized CNTs. After oxidizing, the obtained CNTs were used to remove CuII from aqueous solution. With CuII initial concentration of 20 mg.L-1, at pH of 4 and adsorbent dosage of 0.2 g.L-1, the oxidized CNTs exhibited high CuII adsorption ability with maximum adsorption capacity of 174.4 mg.g-1

Simulating Mangroves Rehabilitation with Cellular Automata

International audienc

Oxidation of dibenzothiophene using the heterogeneous catalyst of tungsten-based carbon nanotubes

Highly effective tungsten-based carbon nanotubes (W/CNT) were synthesized and used as a heterogeneous catalyst for the oxidation of dibenzothiophene (DBT) with the oxidant H2O2. The obtained materials were characterized by modern methods. The Langmuir–Hinshelwood kinetics model described the precursor mechanism of the reaction well through an intermediate compound. The low activation energy showed that the reaction was mainly controlled by diffusion. The positive activation enthalpy proved the endothermic nature of the activation process, and this process did not alter the inside structure of the catalyst. The thermodynamic parameters of the reaction were determined, which implied that the oxidation was endothermic and spontaneous at 303 K. The more negative values of the Gibbs free energy from 283 to 323 K confirmed that the reaction was more favorable at high temperatures. The stability and activity of catalyst were retained after three reaction cycles