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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.

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]

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]

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.

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]

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.