Phân bố hàm lượng chất rắn lở lửng (TSS) tỉnh An Giang sử dụng ảnh viễn thám sentinel 2A

Trầm tích lơ lửng (phù sa) đóng vai trò hết sức quan trọng trong việc cung cấp nguồn dinh dưỡng, có ý nghĩa rất lớn trong sản xuất nông nghiệp và cả hệ sinh thái vùng Đồng bằng sông Cửu long (ĐBSCL). Nghiên cứu đã sử dụng phương pháp hồi quy tương quan giữa giá trị chỉ số vật chất lơ lửng (Normalized Suspended Material Index) trên ảnh và lượng phù sa thực tế để thành lập bản đồ phân bố phân bố không gian hàm lượng tổng chất rắn lơ lửng trong nước mặt (phù sa). Kết quả xác định hệ số R2 trong các hàm hồi quy này đạt 0,868 cho đợt quan trắc ngày 18/10/2019. Kết quả xác định hàm lượng tổng chất rắn lơ lửng từ ảnh Sentinel 2A tỉnh An Giang có giá trị dao động trong khoảng từ 0-100mg/l. Hàm lượng tổng chất rắn lơ lửng tập trung chủ yếu trên các cánh đồng ngập nước, vùng thượng nguồn và cuối nguồn dọc theo tuyến sông Hậu thuộc tỉnh An Giang. Kết quả nghiên cứu cho thấy dữ liệu ảnh Sentinel 2 có khả năng hỗ trợ xây dựng bản đồ phân bố hàm lượng chất lơ lửng nước mặt cụ thể năm 2019 với độ tin cậy cao. Kết quả này là tiền đề cho các đề tài nghiên cứu có liên quan đến tăng giảm hàm lượng phù sa hay chất lượng phù sa vùng ĐBSCL đặc biệt là các vùng cửa sông tại Việt Nam.

TOTAL SUSPENDED SOLID DISTRIBUTION IN HAU RIVER USING SENTINEL 2A SATELLITE IMAGERY

This research was applied high-resolution Sentinel-2A imagery which aims to monitor a suitability of MultiSpectral Imager (MSI) at higher resolution (10 m) for mapping of Total Suspended Solids (TSS) ) in the upper reaches of the Mekong Delta – An Giang province. The field survey is carried out to collect TSS at random distribution sites outside full-dyke protection. A remote sensing algorithm with a regression function method is developed to estimate TSS concentration automatically to select between the most sensitive TSS and water reflectance relationship. The regression analytical algorithm is predicted the output values based on normalized suspended material index (NSMI) (r2 = 0.92), showing the MSI sensor’s great potential to estimate TSS. The results confirm that suspended materials in the surface water reached the minimum of 10.36 mg/l and the maximum of 328.56 mg/l in An Giang province, the suspended materials distributional tendency with high content was mainly in flooded fields near the upstream of the basin of Hau river, especially in areas without the dike enclosure and the content was low in the areas within the dike enclosure. These findings promote further research in water quality studies relying on both operational Sentinel-2A and Sentinel-2B imageries with great implications to improve the understanding of turbid coastal and inland water environments.

Total Suspended Solid (TSS) Estimation in Lake Tempe, South Sulawesi Using Sentinel-2B Imagery

Lake Tempe is located in three districts, namely Wajo, Sidenreng Rapang, and Sopeng, South Sulawesi. The water quality in Lake Tempe needs to be considered both the quality and the quantity of the water. Total Suspended Solid (TSS) is one of the calculations and analysis of air quality. The large of TSS distribution can overcome the effects of sedimentation thereby reducing the need for lakes in saving water. TSS distribution at Lake Tempe can be accessed through Sentinel2B imagery with acquisition time 10 April 2019 and spatial resolution of 10 meters. The algorithm used is NSMI (Normalized Suspended Material Index) algorithm then the results are compared with TSS measurements result in the field. The time of the study was conducted in April 2019 at Lake Tempe, South Sulawesi. The result from samples showed various TSS value which is in the range of 65 mg/L to 203 mg/L with R2of 0.1194 and standard deviation of 8.7106. High TSS value on the banks of the North lakes also had high sedimentation. Low TSS value are in the middle of the lake with small sedimentation and deeper lake

Studies on washability characteristics of low-volatile Indian coking coal by differential crushing

The effect of differential crushing on liberation characteristics has been studied for a low volatile coking coal of Indian origin through washability studies. Two parameters, namely “Index of Washability” (IW) and “Near Gravity Material Index” (NGMI), are used to describe the ease of washability. The ROM Coal is crushed to four different top sizes namely, 75 mm, 25 mm, 13 mm and 6 mm.On the basis of calculated IW it is observed that relative ease of washabiltiy increases with decrease in top size. From calculated IW values it may be said that this coal can be economically beneficiated using gravity process after crushing to -6 mm size. From the calculated NGMI values, the critical specific gravities have been estimated and the values for crushing to -75 mm,-25 mm,-13 mm and − 6 mm are 1.65, 1.68, 1.53 and 1.58 respectively. These critical specific gravity values suggest the separation at this specific gravity range is most difficult task using gravity methods. From NGMI analysis, it may be said that the NGMI values for coals crushed to -25 mm & -6 mm are identical (≈ 0.18) at 17% clean coal ash content. This suggests that with similar degree of difficulty, clean coal of 17% ash can be produced from these two different crushing sizes. In order to increase the yield for the clean coal of 17% ash, the decision on blending these two size coals may need to be taken.

Lexico-word-forming types of nulsufixal nouns in the Ukrainian language of the XI-XIII centuries (male derivatives)

The relevance of the study of the history of null suffix derivation as an important component of the Ukrainian word-forming system is substantiated. The origin of Proto-Slavic derivatives is revealed with the help of thematic vowels *a, *ŏ, *and, *ŭ, which originally served as a means of noun word formation, their original meaning is no longer restored. It was found that the materially expressed suffixes in the Proto-Slavic language had a specific character, they combined two functions: word-forming and inflectional, which gave rise to call them suffixes-inflections or protonulsuffixal forms. Subsequent common language changes (phonetic, morphological) caused the loss of the material index of origin, while preserving the structural and semantic connections of creative and derivative formations. The description of lexical-word-forming types of null suffix masculine deverbatives in the ancient Russian-Ukrainian language of the XI–XIII centuries is carried out. based on the materials of the first written monuments of the Ukrainian language and lexicographical works that reflect the vocabulary of this period. The selected derivatives have a general word-forming meaning “carrier of a procedural feature” or “objectified action or state”. These groups of derivatives represent lexical-word-forming types of names of persons by permanent or temporary occupation or profession, names of persons-bearers of procedural attribute (behavior, views, family relations, social status, etc.), names of subjects of action as a collective concept. Several attributive names of animals, less often of plants, have been documented. Lexical-word-forming types of null-suffix derivatives in the word-forming field of inanimate objects are described: natural phenomena, natural disasters, names of natural objects, locatives, structures, tools, results of physical or intellectual action, etc. In the group of derivatives with the general word-forming meaning “objectified action or state” groups of derivatives are analyzed, which name the action of greater or lesser intensity as an object, names of human actions (positive or negative) human feelings, desires, inner state, names of intellectual action processes. Selected linguistic facts give grounds to assert that the zero-suffix creation of masculine nouns in the ancient Russian-Ukrainian language was a common phenomenon, which laid a strong foundation for further activation of the zero formant in the noun derivation. Keywords: history of null-suffix derivation, pro-noun suffix formants, general word-forming meaning, lexical-word-forming types, carrier of procedural feature, objectified action or state.

Propagation loss on a Si-Slab Waveguide: Simulation revisited

Slab waveguide is one of the simplest types of optical waveguide, the confinement factor is only determined by the thickness of one side so that the propagation of light passing through it will be confined in the material. The slab waveguide is built from Si as the core material and SiO2 as the substrate. The use of various optical waveguides is very dependent on the objectives to be achieved in its application, for it is very important to know the characteristics of each optical waveguide. In this paper the writer wants to know the characteristics of a slab waveguide, specifically with regard to propagation loss. The simulation results show that the propagation loss in the slab waveguide design that the authors propose is around 0.1dB / mm in TE mode conditions. The occurrence of propagation loss in the simulation is likely due to imperfections in determining the effective material index in the design of the slab waveguide.

Determining the Material and Shape of Components within a System Attached to a Wheelchair

The wheelchair has become today indispensable for people experiencing various locomotor disabilities. By investigating the current concepts of solutions to improve the ability to move physically, it was attempted to propose a typology to address the mobility problem. On a basic manual wheelchair, a system will be attached to ensure overcoming the obstacles and to guarantee maintaining the stability of the entire wheelchair. This adjustment will improve the user independence and offer the option of attaching a group of wheels to facilitate smooth movement. By using the Ashby’s graphs that compare the ratio between different properties and by calculating the material index, the optimum material will be determine for the developed system.Ansys software was used to study the structural behaviour under the given boundary conditions by determining the total deformation and equivalent Von Misses stress and then comparisons were made between the obtained results. Also, through topology optimization the most strained areas were discovered and measures were proposed to remedy them.