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In this study, we present a novel approach to injection molding, focusing on the strength of weld lines in polyamide 6 (PA6) composite samples. By implementing a mold temperature significantly higher than the typical molding practice, which rarely exceeds 100°C, we assess the effects of advanced mold temperature management. The research introduces a newly engineered mold structure specifically designed for localized mold heating, distinguishing it as the 'novel cavity.' This innovative design is compared against traditional molding methods to highlight the improvements in weld line strength at elevated mold temperatures. To optimize the molding parameters, we apply an Artificial Neural Network (ANN) in conjunction with a Genetic Algorithm (GA). Our findings reveal that the optimal ultimate tensile strength (UTS) and elongation values are achieved with a filling time of 3.4 seconds, packing time of 0.8 seconds, melt temperature of 246°C, and a novel high mold temperature of 173°C. A specific sample demonstrated the best molding parameters at a filling time of 3.4 seconds, packing time of 0.4 seconds, melt temperature of 244°C, and mold temperature of 173°C, resulting in an elongation value of 582.6% and a UTS of 62.3 MPa. The most influential factor on the PA6 sample's UTS and elongation at the weld line was found to be the melt temperature, while the filling time had the least impact. SEM analysis of the fracture surfaces revealed ductile fractures with rough surfaces and grooves, indicative of the weld line areas' bonding quality. These insights pave the way for significant improvements in injection molding conditions, potentially revolutionizing the manufacturing process by enhancing the structural integrity of the weld lines in molded PA6 samples.

In this work, a photoelectrochemical reactor with an anode based on hybrid structure between conducting polymer polypyrrole (PPy) and porous silicon (PSi) was fabricated and utilized to evaluate the photocatalysis and electro‐assisted photocatalysis for degradation of rhodamine B (RhB) solution. The PSi was made of n‐type silicon single‐crystal wafer by the metal‐assisted chemical etching (MACE). The anode PPy/PSi formed following a polymerization of the PPy on the PSi from the vapour‐phase route using oxidant FeCl3. Typical material characterizations of the PPy, PSi and PPy/PSi were investigated via scanning electron microscope (SEM), and spectroscopies of Fourier‐transform infrared (FTIR), Raman scattering and UV‐vis. Under visible light radiation (halogen light with the wavelength region of 400–700 nm), photocatalytic and electro‐assisted photocatalytic processes of the reactor were conducted by degradation of the RhB solution. A heterojunction (p‐n) of the PPy/PSi was proposed to explain the efficient catalytic performance of the reactor. [ABSTRACT FROM AUTHOR]

Background and objective: The human ficolin-2, encoded by FCN2, recognizes pathogen-associated acetylated residues on their cell surfaces and activates the lectin complement cascade. This study aimed to investigate the contribution of human ficolin-2 and the functional FCN2 genetic variants in dengue virus (DENV) infection and in clinical progression. Methods: FCN2 genetic polymorphisms in the promoter, intron 7 and exon 8 were genotyped in 279 patients with dengue fever and in 200 healthy controls by direct Sanger sequencing. The ficolin-2 levels were measured in serum samples by ELISA and correlated with clinical data. Results: The frequencies of +6031GG, +6220GG and +6424TT genotypes were significantly higher in dengue patients compared to healthy controls indicating an increased risk of dengue fever. The SNPs rs11103563 (+6031A/G), rs7872508 (+6220 T/G), and rs7851696 (+6424G/T) significantly regulated ficolin-2 levels in dengue patients (P < 0.0001). Ficolin-2 levels were increased in patients with dengue and Dengue with Warning Signs (DWS) compared to healthy controls (P < 0.0001 and P = 0.038, respectively). Ficolin-2 levels were significantly increased after 10–14 days of admission in both dengue and DWS patients and then slightly decreased after three weeks of discharge, indicating that ficolin-2 levels were modulated during the progression of dengue fever. In addition, ficolin-2 levels were negatively correlated with AST levels and positively correlated with platelet counts. Conclusions: FCN2 polymorphisms are associated with dengue fever in the Vietnamese population. Ficolin-2 levels are modulated during the progression of dengue fever and correlated with clinical parameters and thus may play a possible role in the pathogenesis of DENV infection.

Abstract Background In high-risk patients with complex pulmonary aspergilloma but unable for lung resection, cavernostomy and thoracoplasty could be performed. This study aimed to evaluate this surgery compared two compressing materials. Methods A total of 63 in high-risk patients who suffered from hemoptysis due to complex pulmonary aspergilloma and underwent cavernostomy and thoracoplasty surgery from November 2011 to September 2018 at Pham Ngoc Thach hospital were evaluated prospectively studied. Patients were allocated to two groups: the table tennis ball group and tissue expander group. We evaluated at the time of before operation, 6 months and 24 months after operation. Results Tuberculosis was the most common comorbidity diseases in both groups. Upper lobe occupied almost in location. Hemoptysis symptoms plunged from time to time. Statistically significant Karnofsky score was observed in both groups. Postoperative pulmonary functions (FVC and FEV1) have remained in both groups at all time points. The remarkable results were no deaths related to surgery and low complications both short and long-term. There was no statistical significance between two groups in operative time, blood loss during operation, ICU length-stay time. Four patients died because of co-morbidity in 24 months follow-up. Conclusion Cavernostomy and thoracoplasty was safe and effective surgery for the treatment of complex pulmonary aspergilloma with hemoptysis in high-risk patients. No mortality related to surgery and low complications were recorded. The was no inferiority when compared two compressing materials .

Data transformation methods are utilized to convert datasets into non-integer formats, potentially altering their distribution patterns. This implies that the variance and standard deviation of the dataset may be altered after the dataset undergoes data transformation operations. Improving model accuracy is a primary application of these methods. This study compares the efficacy of three data transformation techniques: square root transformation, logarithmic transformation, and inverse transformation. The comparison is conducted within the context of developing a surface roughness model for a turning process. Eighteen experiments are performed using the Box-Behnken method, with surface roughness chosen as the response variable. The surface roughness dataset undergoes transformation using the mentioned methods. Four surface roughness regression models are then built: one without transformation, one with square root transformation, one with logarithmic transformation, and one with inverse transformation. Evaluation metrics include coefficient of determination (R-Sq), adjusted coefficient of determination (R-Sq(adj)), Mean Absolute Error (%MAE), and Mean Squared Error (%MSE). Results indicate logarithmic transformation as the most effective, followed by square root transformation, in enhancing model accuracy. The surface roughness model utilizing data transformation exhibits high R-Sq and R-Sq(adj) values, at 0.8792 and 0.7434 respectively. On the other hand, this model has %MAE and %MSE values of only 10.33 and 2.05 respectively. Conversely, inverse transformation exhibits the least effectiveness among the three methods. [ABSTRACT FROM AUTHOR]

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

Purpose. To determine DC leakage current in mine power network with long DC power transmission. Methodology. Nowadays, the increase in capacity and working depth leads to the use of DC power transmission, which has many benefits both economically and technically in mining. However, the appearance of DC power transmission changes the structure of the network. In the underground mine power network, there will be electrical networks with industrial frequency 50 Hz, DC power networks, and power networks after variable frequency inverters. The correlation of these network parameters complicates leakage protection in the mine power network. For DC power transmission in mining, the DC network parts have a large length, so during the working process, electricity leakage in these parts of the network often occurs. Leakage current in a DC network depends not only on DC network parameters but also on AC network parameters. The article uses analytical methods and simulation methods on Matlab/Simulink software to determine leakage currents in underground mine power networks with DC transmission when there is a change in power network parameters. Findings. The research results show that the leakage current value of the DC network is greatly affected when the insulation parameters of the electrical network change, not only in the DC power network but also in the AC network before and after the inverter. This causes the unreliable operation of the leakage protection device in this DC transmission network. Originality. Calculation model and simulation of DC leakage current in underground mine power networks with long DC transmission in mining in Vietnam Practical value. The research results are the basis for calculating and selecting leakage protection equipment for the purpose of improving safety in underground mining in Vietnam. [ABSTRACT FROM AUTHOR]

Simulations and experiments were conducted with gas temperatures of 200–400 °C to investigate the impact of external gas-assisted mold temperature control (Ex-GMTC) on the quality of weld line of molding products. In the heating step, the heating rate was 19.6 °C/s from 30 to 128.5 °C in the first 5 s in a 400 °C gas environment. When applied to heating the weld line area of an injection mold, Ex-GMTC improved the appearance of the weld line when the cavity temperature was preheated to 150 °C. For the tensile strength test, a melt flow simulation comparing the packing pressure of different mesh thicknesses revealed that Ex-GMTC helped maintain a high pressure in the weld line area in different packing periods. This was verified by an experiment where Ex-GMTC was applied with 400 °C gas to change the mesh area temperature. The result indicated that an increase in the weld line area temperature from 60 to 180 °C improves the tensile strength of all mesh thicknesses, which was more pronounced with thinner parts, especially at 0.4 mm. The simulations revealed that high temperature is concentrated in the weld line area of the cavity surface, thus reducing the energy wasted during heating.

To ensure safety in underground mining, it is imperative to equip yourself with electric leakage protection. Today, underground mines are gaining a high degree of mechanization and using more power electronics to enhance the operation and organization of power supplies, including the application of power electronics for DC power transmission in mining. i.e., separate the rectifier (AC-DC) from the inverter (DC-AC) with a long DC cable. The transmission of DC power changes the structure of the mine power network; then there will appear a power network with an industrial frequency of 50 Hz, a DC power network, and a power network after the variable frequency inverter. Due to the mutual interaction between DC power networks and AC power networks, leakage protection devices are unreliable, causing unsafe conditions in mining. The content of the article is to determine the leakage current in the power network when using converters in DC power transmission in mining. The research results are the basis for calculating and selecting leakage protection equipment for the purpose of improving safety in underground mining in Vietnam. [ABSTRACT FROM AUTHOR]

In response to the long-term challenges of skills shortages and mismatches, many countries worldwide have made significant investments in STEM education. However, to obtain a comprehensive understanding of the progress of global research on the implementation of STEM education, it is essential to compile case studies on STEM education. Therefore, we conducted a bibliometric analysis of 750 publications from Scopus database to assess the bibliographic content of case studies on STEM education from 2006 to 2022. Our main findings show that the first case study on STEM education dates back to 2006, and research in this direction has grown enormously and continuously over the last five years (counting for 72.9%). The most influential articles in the field are cited mainly in the background citations section and help provide an initial perspective for readers to understand the insights discussed later in the study. The most popular journals publishing case studies in STEM education are of good quality, ranking highly in Scopus and Web of Science categories. The analysis results show three main research directions: STEM education in higher education, STEM education expands to STEAM, and STEM education activities in K12- education. [ABSTRACT FROM AUTHOR]

Many machining processes would not be possible with)out the presence of cutting oils. There are many different types of cutting oils on the market today, each with different properties. The difference of oils is manifested in many parameters such as viscosity, combustion tempera)ture, recyclability, pollution tendency, stability, price, etc. Choosing the best oil is a difficult and tedious task for customers. In this work, we present the results of a study on the selection of cutting oil using multi-criteria decision-making (MCDM) methods. The selection of the best oil is made on the basis of ranking of seven different types. Two MCDM methods used in this study are Proximity Indexed Value (PIV) and Collaborative Unbiased Rank List Integration (CURLI). This two methods have been used to rank cutting oils. These are two methods with com)pletely different characteristics. When using the PIV method, it is necessary to standardize the data and deter)mine the weights for the criteria. Meanwhile, if using the CURLI method, these two tasks are not needed. In addi)tion, three different weight methods were also used to calculate the weights for the criteria including EQUAL, Rank Order Centroid weight (ROC weight) and Rank Sum weight (RS weight). These three methods have been used to determine the weights for the criteria of cutting oil. The PIV method was used three times corresponding to three different weight methods. The results showed that out of the four ranking results (three using the PIV method and one using the CURLI method), the same best oil was unanimously identified. It is recommended that the CURLI me)thod should be used if weighting of criteria and data nor)malization are not desired. [ABSTRACT FROM AUTHOR]

Photogrammetric processing is available in various software solutions and can easily deliver 3D pointclouds as accurate as 1 pixel. Certain applications, e.g., very accurate shape reconstruction in industrial metrology or change detection for deformation studies in geosciences, require results of enhanced accuracy. The tie-point extraction step is the opening in the photogrammetric processing chain and therefore plays a key role in the quality of the subsequent image orientation, camera calibration and 3D reconstruction. Improving its precision will have an impact on the obtained 3D. In this research work we describe a method which aims at enhancing the accuracy of image orientation by adding a second iteration photogrammetric processing. The result from the classical processing is used as a priori information to guide the extraction of refined tie-points of better photogrammetric quality. Evaluated on indoor and UAV acquisitions, the proposed methodology shows a significant improvement on the obtained 3D point accuracy.

In recent years, there has been a lot of research using reinforcement learning algorithms to train 2-legged robots to move, but there are still many challenges. The authors propose the GCTD3 method, which takes the idea of using Graph Convolutional Networks to represent the kinematic link features of the robot, and combines this with the Twin-Delayed Deep Deterministic Policy Gradient algorithm to train the robot to move. Graph Convolutional Networks are very effective in graph-structured problems such as the connection of the joints of the human-like robots. The GCTD3 method shows better results on the motion trajectories of the bipedal robot joints compared with other reinforcement learning algorithms such as Twin-Delayed Deep Deterministic Policy Gradient, Deep Deterministic Policy Gradient and Soft Actor Critic. This research is implemented on a 2-legged robot model with six independent joint coordinates through the Robot Operating System and Gazebo simulator. [ABSTRACT FROM AUTHOR]

The study on the coatings containing antimony-dope tin oxide mostly has been done on titanium and its alloys for preparation of electrode materials. In this study, we try to prepare the similar coatings on 316L stainless steel, which is more common than titanium, and investigate some characteristics of the formed coatings. The preparation of the coating is by the impregnation of the substrate in solution containing SnCl4 and SbCl3 with the ratio of 93/7, and the concentration of SbCl3, 10 g/L in isopropanol, pH of 1–1.2, and the annealed temperature of 450°C give suitable coating for electrode materials. Some coating features, such as the crystal structure (XRD), morphology (SEM), hardness, electrical resistant, and electrochemical behaviors of the coating on the substrate have been also investigated. The results of the study show that the coatings can be used as electrode materials for the effective treatment of organic colorants in water such as methylene blue in water treatment. [ABSTRACT FROM AUTHOR]

Digital anthropology is the anthropological discipline of the relationship between humans and digital technology. It has been emerging from the Fourth Industrial Revolution, which began at the beginning of the twenty-first century with new technologies. With interaction among people both in physical life and online, the change in method of digital anthropology is closely tied to the theoretical changes in anthropology, especially the formation of postmodern theory emerging from the early 1980s of the twentieth century and its practice to this day. Since post-modern anthropologists concentrate on voices, authority, and power relations between anthropologists and their informants, they call for a more "collective" and "participatory" approach to research and dialogue instead of monologues. To discuss potentials and prospects in Vietnam, this study shows the author's understandings of the historical development of digital anthropology in the world and how this knowledge can be useful for cultural development in communities by engaging postmodernist anthropology with digital anthropology in Vietnam. In the past 20 years, in Vietnam, digital anthropology, also known as visual form, has taken steps to form and has good prospects; however, there is not yet a digital anthropology center with all its functions and duties. Adopting the postmodern turn in anthropology to empower local people in anthropological research, Vietnamese digital anthropologists have changed their roles in ethnographical fieldwork towards shared anthropology. Having experiences with visual anthropology over 20 years, the author foresees a young digital anthropology that requires strong support from traditional theories, especially post-modernist anthropology theories. [ABSTRACT FROM AUTHOR]

In classical photogrammetric processing pipeline, the automatic tie point extraction plays a key role in the quality of achieved results. The image tie points are crucial to pose estimation and have a significant influence on the precision of calculated orientation parameters. Therefore, both relative and absolute orientations of the 3D model can be affected. By improving the precision of image tie point measurement, one can enhance the quality of image orientation. The quality of image tie points is under the influence of several factors such as the multiplicity, the measurement precision and the distribution in 2D images as well as in 3D scenes. In complex acquisition scenarios such as indoor applications and oblique aerial images, tie point extraction is limited while only image information can be exploited. Hence, we propose here a method which improves the precision of pose estimation in complex scenarios by adding a second iteration to the classical processing pipeline. The result of a first iteration is used as a priori information to guide the extraction of new tie points with better quality. Evaluated with multiple case studies, the proposed method shows its validity and its high potiential for precision improvement. [ABSTRACT FROM AUTHOR]

We report preparation and characterization of Si1−xGex alloys with varied composition x of a large range from 0–1. The materials have been obtained by co-sputtering, followed by a heat treatment process at 600, 800, and 1000 °C for 30 min in a nitrogen gas atmosphere. X-ray diffraction data have revealed the formation of single-phase nanoparticles in the face-centered cubic (FCC) structure of Si1−xGex alloys. We found that lattice constant a of the Si1−xGex alloys increased linearly with the composition parameter x. Average diameters of the single-phase nanoparticles were estimated to be between 3–10 nm. Further evidence of FCC single-phase nanoparticles has been obtained by high resolution transmission electron microscopy. From absorption spectra, the gradual shift of the direct phononless transition identified for the E1 point in the Brillouin zone of bulk Ge is observed in single-phase Si1−xGex nanoparticles as a function of the composition parameter x. [ABSTRACT FROM AUTHOR]

This study reports on synthesizing a reduced graphene oxide/magnetite (rGO/Fe3O4) nanohybrid using a one-step process. Iron salt solutions were directly added to a solution containing GO synthesized via the modified Hummers method without requiring additional cleaning steps. The rGO/Fe3O4 nanohybrid synthesized has an average particle size of 15.98 nm with a specific surface area of 74.2 m2/g, exhibits superparamagnetism at room temperature, and has a saturation magnetic moment of 61.9 emu/g. Batch optimization experiments were conducted to evaluate the capability of the rGO/Fe3O4 nanohybrid in removing arsenic (As(V)) from aqueous solutions. The maximum adsorption efficiency of As(V) was about 94.67% after 150 min. These results demonstrate the effectiveness, cost-efficiency, and stability of the method presented for synthesizing the rGO/Fe3O4 nanohybrid material, indicating its potential for widespread application in polluted water treatment. [ABSTRACT FROM AUTHOR]

Backgrounds/aims: Parenchymal-sparing anatomical hepatectomy (Ps-AH) based on portal ramification of the right anterior section (RAS) is a new technique to avoid unnecessarily transecting too much liver parenchyma, especially in cases of major anatomical hepatectomy., Methods: We prospectively assessed 26 patients with primary hepatic malignancies having undergone major Ps-AH based on portal ramification of the RAS from August 2018 to August 2022 (48 months). The perioperative indications, clinical data, intra-operative index, pathological postoperative specimens, postoperative complications, and follow-up results were retrospectively evaluated., Results: Among the 26 patients analyzed, there was just one case that had intrahepatic cholangiocarcinoma The preoperative level of α-Fetoprotein was 25.2 ng/mL. All cases (100%) had Child-Pugh A liver function preoperatively. The ventral/dorsal RAS was preserved in 19 and 7 patients, respectively. The mean surgical margin was 6.2 mm. The mean surgical time was 228.5 minutes, while the mean blood loss was 255 mL. In pathology, 5 cases (19.2%) had microvascular invasion, and in the group of HCC patients, 92% of all cases had moderate or poor tumor differentiation. Six cases (23.1%) of postoperative complications were graded over III according to the Clavien-Dindo system, including in three patients resistant ascites or intra-abdominal abscess that required intervention., Conclusions: Parenchymal-sparing anatomical hepatectomy based on portal ramification of the RAS to achieve R0-resection was safe and effective, with favorable short-term outcomes. This technique can be used widely in clinical practice.

Stokes polarimeters are most commonly used to measure the state of polarization of optical wave. Dependence of Stokes parameters, degree of polarization on external magnetic field are presented for garnet and groove films on garnet in the transmission and reflection modes. The Stokes parameters S1, S2, S3 of different modes show different tendency and asymmetrically change when the external magnetic field change, while the degree of polarization basically unchange.

A Faraday Effect sensor with Nd(2)Fe(14)B biasing magnetic film was described. Ta/Nd(2)Fe(14)B/Ta films were grown by magnetron sputtering method. The magnetic domain in the sensor with the Nd(2)Fe(14)B biasing magnetic film can persist its distribution. The average linearity error of Faraday Effect sensor with biasing magnetic film decreased from 1.42% to 0.125% compared with non-biasing magnetic film, and the measurement range increased from 820 Oe to 900 Oe.