Journal of Science and Technique
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EFFICACY OF A DCBRN-01VN SKIN DECONTAMINANT ON ANIMALS EXPOSED TO 2-CHLOROETHYL ETHYL SULFIDE
Get PDFChemical warfare agents are an actual threat and decontamination for victims is a main concern when mass exposure occurs. The study evaluated the effectiveness of the skin decontamination agent DCBRN-01VN based on the oxime compound KBDO for CEES (2-chloroethyl ethyl sulfide). HPLC analysis method was used to determine the temperature after decontamination in vitro and in vivo tests and then to check biochemical and hematological indicators in rats. The test results show that DCBRN-01VN has a high efficiency of CEES decontamination, in vitro: with the ratio of CEES: decontaminant 1:20 in 10 minutes reaching 55.04%, with the ratio 1:10 in 20 minutes reached 55.95%, in 30 minutes reached 82.93%, in 60 minutes reached nearly 100%; in vivo test with a ratio of 1:15 in 20 minutes reached almost 100%. Results of biochemical and hematological examination showed no difference between the negative control group and two experimental groups (with decontamination and without decontamination) P(2-1) > 0.05; P(3-1) > 0.05. Histopathological analysis showed that decontamination also reduced damage caused by CEES
PREDICTING TEMPERATURE DISTRIBUTION IN HANOI REGION'S ASPHALT PAVEMENT THROUGH NUMERICAL SIMULATION
Get PDFThis article presents determining the temperature distribution in asphalt pavement in the Hanoi area based on numerical simulation using FEM. Climate data were collected from freely available online data from the Federal Highway Administration of the United States. From this data, the surface temperature of the pavement was calculated, which served as the boundary condition for the heat transfer problem of the pavement. The results show that the pavement surface temperature is typically highest around 11 a.m. to 12 p.m., while the lowest temperature is typically around 4 a.m. to 6 a.m. The temperature inside the pavement layer is usually high between 10 a.m. and 4 p.m. when the strength and deformation resistance of the pavement are relatively low. In contrast, the temperature inside the pavement is low during the period between midnight and 6 a.m., when the asphalt concrete becomes brittle and is easy to crack. The analysis of the temperature distribution in the pavement structure can be used for calculating and designing the pavement, as well as predicting pavement rutting
ENSEMBLE LEARNING APPROACHES FOR CLASSIFICATION WITH HIGH-DIMENSIONAL DATA
Get PDFClassification with high-dimensional data is a significant challenge in machine learning because the abundance of features in high-dimensional data makes it difficult to identify meaningful patterns, which leads to overfitting and reduced classification performance. Moreover, the computational cost of processing high-dimensional data is often prohibitively expensive, requiring specialized hardware or optimized algorithms. Ensemble learning is a powerful machine learning technique that combines multiple models to improve classification accuracy. By aggregating the predictions of multiple models, ensemble learning can reduce overfitting, increase robustness, and improve performance on a wide range of real-world classification problems. Ensemble learning is effective for classification with high-dimensional data because it can combine multiple models to mitigate the effects of the curse of dimensionality, reduce overfitting, and enhance generalization performance. By using different learning algorithms or subsets of features, ensemble learning can improve the diversity of the models, leading to better overall performance on high-dimensional data. This paper proposes two hybrid ensemble machine learning approaches that integrate random subspace ensemble with bagging and boosting to enhance classification performance with high-dimensional data. Experimental results demonstrate that these methods significantly improve classification accuracy with highdimensional data
CROSS-FREQUENCY DOMAIN FOR JPEG INVERSIBLE WATERMARKING USING MULTIPLE QUANTIZATION TABLES
Get PDFReversible data hiding techniques for JPEG images have big challenges in order to improve the capacity, quality, and flexible embedding method. In this article, we propose a new crossdomain using combination of multiple quantization tables in JPEG algorithm. We survey the efficiency of quantization coefficients on the DCT tables in order to decide the way to embed the watermark information. Compared to the conventional method, our experimental results show that our proposed method has better performance in term of both the increasing capacity and improving the quality of embedded JPEG images after data embedding
PHƯƠNG PHÁP SỐ VÀ THỰC NGHIỆM ĐÁNH GIÁ ĐẶC TRƯNG BỀN MỎI CỦA CHI TIẾT MÁY KHI CHỊU TRẠNG THÁI ỨNG SUẤT PHỨC TẠP
Get PDFXác định đặc trưng bền mỏi của chi tiết máy có vai trò quan trọng trong quá trình tính toán, thiết kế máy. Tuy nhiên, khi chi tiết máy chịu trạng thái ứng suất phức tạp, việc xác định trực tiếp đặc trưng bền mỏi của chúng theo phương pháp truyền thống là vấn đề hết sức phức tạp. Trong bài báo này, các tác giả trình bày kết quả nghiên cứu phát triển một phương pháp số cho phép tính toán, khảo sát giới hạn bền mỏi của chi tiết máy khi chịu trạng thái ứng suất, biến dạng phức tạp theo các tiêu chí khác nhau, đồng thời trình bày các kết quả nghiên cứu thực nghiệm xác định giới hạn bền mỏi của chi tiết máy trong trạng thái ứng suất phức tạp với hai dạng mẫu khác nhau trên cơ sở sử dụng bàn rung LDS. Các kết quả nghiên cứu số và thực nghiệm cho thấy, khi chịu trạng thái ứng suất phức tạp, việc đánh giá đặc trưng bền mỏi theo phương pháp ứng suất chính thứ nhất cho kết quả sai số lớn nhất, trong khi đó phương pháp mặt phẳng tới hạn cho kết quả tin cậy hơn cả
CONSTRUCTION SEQUENCE ANALYSIS OF REINFORCED CONCRETE HIGH-RISE BUILDINGS
Get PDFThis article studies the influence of the construction sequence on the response of reinforced concrete high-rise buildings. Currently, most structural systems are analyzed in only a single step with the assumption that the system can bear the entire load from the completed whole building. In reality, a structure is constructed sequentially floor by floor, which leads to differences between the theoretical analysis and the actual response of structural system, especially for the structural system of high-rise buildings. After conducting construction sequence analysis, the effecting results on the internal forces of columns and beams of the changeable high skycraper are synthesized, compared with using the conventional technique
DEVELOPING A PROCESS TO EVALUATE THE EFFECTIVENESS OF INFRARED CAMOUFLAGE UNIFORMS IN JUNGLE-MOUNTAINOUS TERRAIN
Get PDFDeveloping methods to evaluate the effectiveness of camouflage against thermal reconnaissance devices reliably and close to reality is an urgent requirement today. Therefore, applying camouflage solutions against thermal reconnaissance equipment has been developing rapidly in many countries. However, to reach the target, it is essential to develop a process and method to evaluate the properties of camouflage materials and means in the laboratory, simulate targets in the virtual environment, and asset the effectiveness of camouflage directly at the scene. In Vietnam, research in the field still needs more information and has only recently been implemented. To deal with the target above, the research team conducted studies to develop and evaluate the effectiveness of thermal camouflage. This article focuses on developing a complete procedure for the field method to evaluate the effectiveness of thermal camouflage. The result can be applied to evaluate and select the thermal camouflage material and facilities in jungle - mountainous terrain.Thermal imagin
EPOXY RESIN, VINYL COPOLYMER, AND RICE HUSK SILICA BASED TERNARY NANOCOMPOSITES: FABRICATION, MECHANICAL CHARACTERISTICS, AND THERMAL AGING
Get PDFIn this research, the bio-composites based on epoxy resin filled with nano-silica and vinyl copolymer were fabricated using diethylene triamine as a curing agent and casting method. The vinyl copolymer was synthesized from Hydroxyethyl Acrylate and Methacrylic acid using ammonium persulfate as an initiator. The bio-silica was extracted from rice husk via a simple technique of acid treatment and calcination. The chemical structure of poly(HEA-Co-MAA), silica was confirmed with help of the FTIR, and NMR-1H. The high-speed mechanical stirrer was used to obtain the good dispersion of silica and poly(HEA-Co-MAA) in epoxy resin before mixing and curing with Diethylenetriamine (DETA) hardener. The thermal stability of cured epoxy resin was enhanced with the presence of rice husk silica and poly(HEA-Co-MAA). The composite sample with 1 wt.% of bio-silica and 3 wt.% of poly(HEA-Co-MAA) showed the best mechanical properties with an improvement of up to 28.82%; and 35.36% of impact strength and tensile strength, respectively when compared with a pristine sample. The aging testing was also performed to investigate the effect of additive added on the thermal resistance of epoxy resin
STUCNET – SWIN TRANSFORMER-V2 UNET FOR CRACK SEGMENTATION NETWORK
Get PDFAutomatic crack detection on road surfaces is an important task for supporting the quality control of road infrastructure in transportation. Various methods have been proposed for crack segmentation, but their accuracy is still limited. To improve the effectiveness of crack detection, we propose the Swin Transformer v2 U-Net for Crack Segmentation Network model (STUCNet) for crack recognition. The proposed model combines the advantages of the Swin Transformer v2 into the encoding module of the U-Net-based architecture to enhance the quality of semantic image segmentation. Specifically, the model integrates Swin Transformer v2 with shifted windows as the encoder to extract contextual features for crack segmentation. The symmetric decoder is based on a convolutional neural network with attention designed to perform upsampling operations to restore the spatial resolution of the feature map. We evaluate the STUCNet model on a large dataset containing cracks collected in different contexts. Compared to current advanced models, the proposed method achieves the state-of-the-art (SOTA) results for crack segmentation
KHẢO SÁT MỘT SỐ CHẤT HÓA DẺO CHO NHIÊN LIỆU RẮN HỖN HỢP TRÊN NỀN POLYVINYL CLORUA
Get PDFBài báo trình bày kết quả khảo sát một số chất hóa dẻo cho nhiên liệu rắn hỗn hợp. Nhiên liệu rắn hỗn hợp được chế tạo từ PVC hóa dẻo bởi DOP, DOA và hỗn hợp DOP/DOA với chất oxi hóa ammoni peclorat (AP), chất cháy bột nhôm (Al) và xúc tác cháy bột sắt (III) oxit (Fe2O3). Các tính chất cơ học và đặc trưng nhiệt đã được xác định. Kết quả cho thấy các mẫu nhiên liệu có các đặc trưng đáp ứng được yêu cầu của nhiên liệu rắn hỗn hợp như: mô đun đàn hồi 176,7 ÷ 202,9 MPa, độ biến dạng 28 ÷ 45 %, nhiệt độ bùng cháy 304,8 ÷ 308,4°C và độ bền nhiệt 0,081 ÷ 0,178 ml/g. Chất hóa dẻo DOP có hiệu quả hóa dẻo PVC tốt hơn so với DOA. Bên cạnh đó, nhiên liệu được hóa dẻo bởi DOA gây ra giảm khối lượng mạnh hơn khi già hóa và độ bền nhiệt thấp hơn so với DOP