Investigation on high-strength low alloy 0.35Cr-1.9Ni-0.55Mo steel deposited on 20Cr substrate by wire and arc-based directed energy deposition

This article aims to observe the microstructure, mechanical properties, and interface bonding of a 0.35Cr-1.9Ni-0.55Mo alloy deposited on 20Cr steel by wire and arc-based directed energy deposition (WA-DED). For this purpose, different characterization techniques such as optical microscope, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and high-resolution X-ray diffractometer were used to analyze microstructure, chemical composition, and phases of the deposited material. Microhardness and tensile tests were also carried out. The results show that the microstructure of the deposited material is relatively homogeneous with a slight increase in grain size from the bottom to the top of the deposited part, thus resulting in a gradually decreasing trend in microhardness, from 288±16.78 HV0.1 (in the bottom) to 256±17.04 HV0.1 (in the top). The heat-affected zone (HAZ) is the hardest (301±2.70 HV0.1), while the substrate has the lowest microhardness (203±17.64 HV0.1). The tensile strengths of deposited materials are relatively isotropic in both the horizontal direction (HD) and vertical (VD) direction: UTSVD = 1013±9.29 MPa, USTHD = 985±24.58 MPa, YS(0.2%)VD = 570±4.51 MPa, and YS(0.2%)HD = 614±19.66 MPa. The tensile strengths of interface specimens are also comparable to those of the substrate materials (e.g., 951 vs. 972 MPa in UTS), indicating an excellent metallurgical bonding between the deposited and substrate materials. The results of this work confirm the efficiency of WA-DED technique to produce high-quality components in industr

Metallurgical Characterization of SS 316L Repurposed by Wire plus Arc Additive Manufacturing

This research aims to analyze the microstructures and mechanical characteristics of stainless steel (SS) 316L repurposed by wire plus arc additive manufacturing (WAAM). The SS 316L wire is deposited on a SS 316 substrate, which can be repurposed. This deposited material underwent optical microscopy, X-ray diffraction, and tensile test, and the results indicate that it features cellular and columnar dendrites at the bottom and equiaxial grains at the top. The tensile strength of the interface region between the deposited material (DM) and the base material (BM) is the highest (559 ± 4.16 MPa vs. 510 ± 4.93 MPa in DM and 540 ± 2.65 in BM), indicating that the BM and the deposited layers are strongly bonded. All the results from the defect observation, microstructures, and mechanical characteristics confirm the potential of the WAAM process for repurposing

Silvicultural Characteristics Of Dipterocarpus Rensus In Thai Nguyen Province, Vietnam

Dipterocarpus rensus, a long-exploited species in Thai Nguyen Province, Vietnam, is currently documented with only 244 individuals observed across scattered locations within strictly protected natural forests. This study aimed to elucidate the distribution and silvicultural characteristics of D. rensus in Thai Nguyen, providing essential insights for the conservation and sustainable development of its genetic resources. Our findings underscore a sparse population of D. rensus in Thai Nguyen, primarily concentrated within National Parks and Conservation Areas. The species composition formula for the natural distribution of D. rensus encompasses diverse tree species, including Broussonetia papyrifera, Allospondias lakonensis Pierre, Choerospondias axillaris, Fagus sylvatica, Machilus velutina Champ, Canarium album, Engelhardtia chrysolepis, Peltophorum dasyrhachis, Alangium chinense, Vatica odorata, Duabanga grandiflora, Sargentodoxa cuneata, Amesiodendron chinense, and Nephelium chryseum. The regenerative seedling composition is dominated by pioneer, fast-growing species such as Broussonetia papyrifera, Allospondias lakonensis Pierre, Fagus sylvatica, Machilus velutina Champ, Zenia insignis, Engelhardtia chrysolepis, Archidendron clypearia, Pterospermum acerifolium Willd, Bischofia javanica, Vatica odorata, Duabanga grandiflora, Sargentodoxa cuneata, Broussonetia papyrifera, Aesculus assamica, and Amesiodendron chinense. The study highlights the poor regeneration ability of D. rensus, emphasizing the necessity for research on cultivation techniques to effectively conserve and harness the genetic resources of this valuable species

1M parameters are enough? A lightweight CNN-based model for medical image segmentation

Convolutional neural networks (CNNs) and Transformer-based models are being widely applied in medical image segmentation thanks to their ability to extract high-level features and capture important aspects of the image. However, there is often a trade-off between the need for high accuracy and the desire for low computational cost. A model with higher parameters can theoretically achieve better performance but also result in more computational complexity and higher memory usage, and thus is not practical to implement. In this paper, we look for a lightweight U-Net-based model which can remain the same or even achieve better performance, namely U-Lite. We design U-Lite based on the principle of Depthwise Separable Convolution so that the model can both leverage the strength of CNNs and reduce a remarkable number of computing parameters. Specifically, we propose Axial Depthwise Convolutions with kernels 7x7 in both the encoder and decoder to enlarge the model receptive field. To further improve the performance, we use several Axial Dilated Depthwise Convolutions with filters 3x3 for the bottleneck as one of our branches. Overall, U-Lite contains only 878K parameters, 35 times less than the traditional U-Net, and much more times less than other modern Transformer-based models. The proposed model cuts down a large amount of computational complexity while attaining an impressive performance on medical segmentation tasks compared to other state-of-the-art architectures. The code will be available at: https://github.com/duong-db/U-Lite.Comment: 6 pages, 7 figure

Effects of scanning methods on cracking, microstructures and microhardness of Inconel 625 parts formed by direct laser metal deposition

This study aims at investigating the effects of scanning methods on the stress distribution and microstructures of Inconel 625 thin-walled part fabricated by direct laser metal deposition. The results showed that with the single direction scanning (SDS) method, the residual stress at both the ends of the thin wall was relatively high while the stress at the middle was smaller with a stress difference of about 1800 MPa. In contrast, with the reverse direction scanning (RDS) method, the residual stress in the thin wall was distributed relatively evenly, with a stress difference of about 350 MPa between both the ends and the center. The experimental results showed that, in the SDS method, cracks occurred at both ends and in the middle of the thin wall, whereas in the RDS method, warping and cracks phenomena were eliminated. The microstructure of the Inconel 625 in the forming layer is characterized by a columnar crystal structure that has a small length and grows perpendicularly to the scanning direction. This growth is continuous between the forming layers. In both cases, the microhardness increases with the height of the formed layers. The microhardness values are relatively uniform with values ranging from 420 to 450 HV

The 3-3-1 Model with Arbitrarily Charged Leptons

The gauge  model based on $\mathrm{SU}(3)_C\otimes \mathrm{SU}(3)_L\otimes \mathrm{U}(1)_X$  group with arbitrarily electric charged exotic leptons is presented. The mass eigenvalues and eigenstates for  neutral gauge bosons are presented in the general form. We show that in the 3-3-1 models, there always exists triple Higgs self-coupling. The lepton number operator is also presented

Knowledge of Antiretroviral Treatment and Associated Factors in HIV-Infected Patients

This study aimed to assess the knowledge of antiretroviral (ARV) treatment and the associated factors in HIV-infected patients in Vietnam. We conducted a cross-sectional descriptive study of 350 human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients being treated with ARV at outpatient clinics at Soc Trang, Vietnam, from June 2019 to December 2019. Using an interview questionnaire, patients who answered at least eight out of nine questions correctly, including some required questions, were considered to have a general knowledge of ARV treatment. Using multivariate logistic regression to identify factors associated with knowledge of ARV treatment, we found that 62% of HIV-infected patients had a general knowledge of ARV treatment, with a mean score of 8.2 (SD 1.4) out of 9 correct. A higher education level (p < 0.001); working away from home (p = 0.013); getting HIV transmitted by injecting drugs or from mother-to-child contact (p = 0.023); the presence of tension, anxiety, or stress (p = 0.005); self-reminding to take medication (p = 0.024); and a high self-evaluated adherence (p < 0.001) were found to be significantly associated with an adequate knowledge of ARV treatment. In conclusion, education programs for patients, as well as the quality of medical services and support, should be strengthened

Pneumonia: Drug-Related Problems and Hospital Readmissions

Pneumonia is one of the most common infectious diseases and the fourth leading cause of death globally. According to US statistics in 2019, pneumonia is the most common cause of sepsis and septic shock. In the US, inpatient pneumonia hospitalizations account for the top 10 highest medical costs, totaling $9.5 billion for 960,000 hospital stays. The emergence of antibiotic resistance in the treatment of infectious diseases, including the treatment of pneumonia, is a globally alarming problem. Antibiotic resistance increases the risk of death and re-hospitalization, prolongs hospital stays, and increases treatment costs, and is one of the greatest threats in modern medicine. Drug-related problems (DRPs) in pneumonia - such as suboptimal antibiotic indications, prolonged treatment duration, and drug interactions - increase the rate of antibiotic resistance and adverse effects, thereby leading to an increased burden in treatment. In a context in which novel and effective antibiotics are scarce, mitigating DRPs in order to reduce antibiotic resistance is currently a prime concern. A variety of interventions proven useful in reducing DRPs are antibiotic stewardship programs, the use of biomarkers, computerized physician order entries and clinical decision support systems, and community-acquired pneumonia scores

A modern purification by accelerated solvent extraction and centrifugal partition chromatography and biological evaluation of capsaicin from Capsicum chinense

A special alkaloid compound known as capsaicin, which can only be found in the fruit of the Capsicum plant, was isolated and tested for its anti-inflammatory activity. The purpose of this work is to establish a simple and quick approach for capsaicin purification utilizing centrifugal partition chromatography (CPC) as well as an effective method - accelerated solvent extraction (ASE), for extracting capsaicin from Capsicum chinense. After purification, capsaicin was validated by HPLC-DAD at 281 nm to be &gt; 90% purity. The in vivo anti-inflammatory activity of the isolated capsaicin was also investigated, and the IC50 value of the capsaicin was determined to be 57.61 µg/mL. The current work emphasizes how an ASE and CPC system may combine to extract high-purity capsaicin from Capsicum chinense, which have the anti-inflammatory activity, as we evaluated in the experiment

Phân vùng khí hậu và đánh giá sự phù hợp của cây trồng trên địa bàn huyện Kỳ Anh, tỉnh Hà Tĩnh

Hầu hết các khuyến cáo nông nghiệp của các huyện thuộc tỉnh Hà Tĩnh đều dựa trên cơ sở về địa giới hành chính và các thông tin dự báo thời tiết, khí hậu ở cấp vùng hoặc cấp tỉnh. Tuy nhiên, trong thực tế, các yếu tố khí hậu biến động không đồng nhất giữa các vùng trong cùng một địa giới vì chúng phụ thuộc nhiều vào các điều kiện tự nhiên như độ cao, địa hình, thảm thực vật. Tương tự như vậy, huyện Kỳ Anh, một huyện ven biển của tỉnh Hà Tĩnh, miền Trung Việt Nam, từ trước tới nay chưa có bản đồ phân vùng khí hậu và đánh giá sự phù hợp của cây trồng dựa trên các cơ sở dữ liệu về đặc điểm tự nhiên như khí hậu, địa hình, độ cao. Mặt khác, người dân huyện Kỳ Anh lại luôn phải đối mặt với các sự kiện thời tiết cực đoan như lũ lụt trong mùa mưa, hạn hán kéo dài nhiều tháng trong mùa khô, rét đậm, rét hại trong mùa đông và gió Tây khô nóng trong mùa hè. Các sự kiện thời tiết cực đoan này đã gây ảnh hưởng rất lớn đến sản xuất nông lâm nghiệp hay sinh kế của người dân địa phương. Vì thế, việc phân vùng khí hậu cũng như đánh giá sự phù hợp của các lọai cây trồng với các tiểu vùng khí hậu trong huyện là rất cần thiết. Báo cáo này sẽ trình bày (1) phương pháp và (2) kết quả của việc nghiên cứu, lập bản đồ phân vùng khí hậu và (3) kết quả đánh giá sự phù hợp của một số loại cây với điều kiện tự nhiên của huyện Kỳ Anh để giúp các cán bộ địa phương chỉ đạo sản xuất nông nghiệp có hiệu quả, tránh được các rủi ro về khí hậu và phát huy tối đa lợi thế của địa phương