Research of methods for determining dynamic stress of the bars in the main structure of gantry crane installed on the cap of bridge pier to serve installation of Super-T girder

The article presents briefly findings in researching methods for determining dynamic stress of the bars in the main structure of gantry crane installed on the cap of bridge pier to install and launch SUPER-T girder. In order to study the dynamic stresses in the bars of the main truss structure of the gantry, the author first had to build a dynamic model, using Matlap software to solve the problem of dynamics with two cases cargo lowering combination combines braking and moving of gantry with cargo to find out the rules and values of dynamic cable tension, dynamic inertial force ( time-varying force), then consider these forces is the external force acting on the main truss structure model of the gantry, from which the author calculates the value of internal force and stress of each bar corresponding to the value of dynamic cable tension and corresponding dynamic inertia force. with two adverse working cases of the gantry. Using Matlap software to calculate the author has obtained a graph of internal force, stress changes over time of each bar in the main truss steel structure of the gantry. The findings of the research provided methods for determining the dynamic stress of the bars in the main structure of gantry crane, pointed out values and rules of change of the dynamic stress of the bars in the main structure of gantry crane. The findings of the research may be used to calculate fatigue, life-span of the main steel structures as well as other parts of the gantry cran

Optimization of Technological Parameters when Plasma Nitriding the Gear Working Surface

This paper presents the results of optimizing the technological parameters when plasma nitriding the gear working surface. 27 experiments were carried out on an H4580 Eltrolab instrument to obtain a working surface hardness database table, and the Minitab statistical software was used to process the experimental results. A regression equation was identified to analyze the influence of temperature, time, and gas permeation concentration on the hardness of the working surface. An analysis of variance (ANOVA) showed that all these nitriding parameters influence the regression equation. The results showed that the permeation temperature TL has the greatest influence on the hardness, while the permeation time h and the first gas permeation concentration G1 had less influence. An optimal set of technological parameters was established, where the permeation temperature was TL=550°C, permeation time was h=8h, and the first gas permeation concentration was G1=4l/h. Experiments were carried out using this set of optimal parameters to evaluate the microstructure and the depth of the hardening layer of the part surface. Finally, this study presented the whole process for the permeation and plasma nitriding of 18XГT steel

Surface Roughness Modeling of Hard Turning 080A67 Steel

Surface roughness is an important parameter to evaluate the quality of a machining process in mechanical manufacturing. The construction of a surface roughness model of a machining process is the basis for predicting surface roughness corresponding to each certain case. This paper presents the construction of a surface roughness model in 080A67 steel turning. An experimental process was carried out with a total of 15 experiments, designed according to the Box-Behnken matrix. The cutting speed, feed rate, and cutting depth were changed in each experiment, and surface roughness values were measured to build a model that showed the mathematical relationship between surface roughness and the three cutting parameters. A second surface roughness model was also constructed using the Box-Cox transformation. The accuracy of these two models was compared through five coefficients: R2, R2(pred), R2(adj), Percentage Absolute Error (PAE), and Percentage Square Error (PSE). The results showed that all these coefficients of the model using the Box-Cox transformation were better than those of the first one. In detail, the values of R2, R2(pred), R2(Adj), PAE, and PSE of the first model were 94.55%, 12.79%, 84.74%, 8.79%, and 1.42%, while for the second model were 99.09%, 85.42%, 97.44%, 2.26%, and 0.18%, respectively, showing that the accuracy of the surface roughness model was improved by using the Box-Cox transformation

A Design of Similar High-gain and Dual-band Frequency/Polarization Reconfigurable Antenna for ISM Band Applications

This paper proposes a frequency/polarization reconfigurable antenna (RA) incorporating with Frequency Selective Surface (FSS) to achieve dual-band and similar high-gain characteristics. The proposed RA-FSS design using 4 PIN Diodes can switch between circular polarization (CP) at 1.8 GHz and linear polarization at 2.45 GHz. The fabricated prototype shows good CP performance at 1.8 GHz while the measured peak broadside gains are about 7.2 dBi at 1.8 GHz and 8.5 dBi at 2.45 GHz when PIN diode ON and OFF, respectively

CAMELLIA QUYNHII (THEACEAE, SECT. STEREOCARPUS), A NEW YELLOW SPECIES FROM THE CENTRAL HIGHLANDS, VIETNAM

Camellia quynhii is described and illustrated as a new species of section Stereocarpus (Pierre) Sealy from 12th village, Vu Bon Commune, Krong Pak District, Dak Lak Province. C. quynhii resembles C. dormoyana (Pierre) Sealy but differs in several morphological characteristics: sepals 6–7; petals about 12–15; filaments tomentose at the base; style 3(–4), basally united; capsule 3(–4) locular, 2–6 seeds in each locule. Information on its phenology, distribution, ecology, and conservation status is also provided.Camellia quynhii is described and illustrated as a new species of section Stereocarpus (Pierre) Sealy from 12th village, Vu Bon Commune, Krong Pak District, Dak Lak Province. C. quynhii resembles C. dormoyana (Pierre) Sealy but differs in several morphological characteristics: sepals 6–7; petals about 12–15; filaments tomentose at the base; style 3(–4), basally united; capsule 3(–4) locular, 2–6 seeds in each locule. Information on its phenology, distribution, ecology, and conservation status is also provided

The Relationship Between Corporate Social Responsibility and Employee Organizational Commitment in Multinational Corporations in Ho Chi Minh City

Based on the theoretical background of previous studies and the increasing context of personnel turnover in multinational companies, the authors conduct this study with the research objective to test and measure the impact of Corporate Social Responsibility (CSR) on employee’s organizational commitment through the effect of organizational identification and organizational trust. The combined qualitative and quantitative research methods were used to process and analyse the data. Research data was collected from 271 employees working in multinational corporations in Ho Chi Minh City. The study also discusses and provides some governance implications to help MNCs improve their social responsibility towards social and non-social stakeholders, employees, customers and the government as well as increase employee organizational engagement through identification and trust in the organization. Keywords: corporate social responsibility, employee organizational commitment, organizational identification, organizational trus

Enabling Smart Factory with deep Residual-Aided generative adversarial network: Performance analysis end-to-end learning of Machine-to- Machine

Improving Machine-to-Machine (M2M) communication is essential for the development of Smart Factory as data can be exchanged and processed more efficiently. Herein this study, we employ the Deep Learning (DL) concepts aimed at improving end-to-end performance (E2E) M2M communication systems. Training the physical layers requires the explicit channel information to be fully known, which can be solved with generative adversarial network (GAN). Nonetheless, due to its deep neural network (DNN) structure, the GAN scheme is subjected to gradient vanishing and over-fitting, two major obstacles that can hinder the training process and limit the performance of the model. As a result, the system is significantly downgraded. To address these issues, we study a method known as Residual-Aided generative adversarial network (RA-GAN) learning scheme, in which the two problems are dealt with respectively by introducing a better propagation mechanism and a regularizer to the loss function. Herein this paper, the system model is described and the two problems are derived analytically. We also analyze the optimal learning scheme (where the channel-agnostic) and a Rayleigh-based learning scheme for comparison study. Through analyzing the block error rate (BLER), we can demonstrate that the RA-GAN approach achieves performance comparable to the optimal scheme, and significantly outperforms the conventional GAN method.Web of Science20236533652

A study on the influence of printing orientation in metal printing using material extrusion technology on the mechanical properties of 17-4 stainless steel products

This study investigated the influence of print orientation on the mechanical properties of 17-4 PH stainless steel parts fabricated using material extrusion technology. Tensile test specimens were 3D printed in different orientations (flat, on-edge, and upright), and their mechanical properties were evaluated. The results showed that the print orientation significantly affected the ultimate tensile strength, yield strength, and elongation at failure of the specimens. The flat and on-edge orientations exhibited similar mechanical properties, while the upright orientation resulted in lower strength and higher fracture susceptibility. Hardness measurements also indicated variations in hardness distribution among the orientations. The findings emphasize the importance of optimizing the print orientation parameter to achieve desired mechanical characteristics in 17-4 PH stainless steel parts

Effects of Land Quality on Land Use: Farm-level Panel-data Evidence from Viet Nam

The sustainable livelihoods framework (SLF) is a comprehensive way to study agricultural issues. So far, to our best knowledge, no study has applied the SLF to examine the influence of land quality on land use intensively. The current research examines the effects of land quality on farmers’ decision-making on land use in Vietnam by modifying the sustainable livelihoods framework and using the fixed effects regression model. The method controlled the household and commune-level unobserved invariant characteristics and resulted in more robust estimates than pooled Ordinary Least Squares (OLS) estimation. The sample is a five-wave panel dataset of 2008-2016 with 1,534 farm households. The results reveal that land quality affects land-use choices through several aspects of land quality. More specifically, regarding topography, plot fertility level, plot locations, and soil and water conservation, results show that their effects reflect the cultivating practices for each land-use type in the sample. Findings also show that the irrigation system positively affects rice production in Vietnam. Policymakers should consider various aspects of land quality when designing policies and programs relating to land use, irrigation distribution, and especially the master plan for agricultural production and rural development. Flexible guidance for land uses of each type is closely connected with land quality in each region that may be most suitable for sustainable agriculture development

Застосування методів topsis, mairca та EAMR для багатокритеріального прийняття рішень при шліфуванні кругами з кубічного нітриду бору

Determining the best cutting mode is a common problem for machining processes as well as for CBN (Cubic Boron Nitride) grinding on Computer Numerical Control (CNC) machines. It is even more important when it is necessary to choose a solution that meets many goals, which are in conflict. This paper presents the results of a multi-criteria decision-making (MCDM) study on CBN grinding of cylindrical-shaped parts on CNC milling machines. Three MCDM methods,  including TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution), MAIRCA (Multi-Attributive Ideal-Real Comparative Analysis), and EAMR (Evaluation by an Area-based Method of Ranking) were applied in this work. Besides, MEREC (Method based on the Removal Effects of Criteria) and Entropy methods were used to determine the weights of the criteria. In addition, the Taguchi method with L18 orthogonal array (6^1+3^3) design was used for the design of an experiment, which has four input factors including the depth of dressing cut, the spindle speed, the feed rate, and the wheel diameter. Two criteria, including the surface roughness (SR) and the material removal speed (MRS) were selected as the response outputs. The reason for choosing these two criteria is because SR and MRS are two very important output factors of a mechanical machining process as well as of the CBN grinding process on a CNC milling machine. In particular, these two criteria are always in conflict with each other. Small SR requirements will require small values of the feed speed and the depth of cut. This will lead to the reduction of MRS. From the results of this study, the use of different methods for MCDM was evaluated. In addition, rankings of alternatives have been given according to MCDM methods. Furthermore, the best alternative to guarantee both the minimum SR and the maximum MRS has been foundВизначення найкращого режиму різання є поширеною задачею у процесах механічної обробки, а також шліфування кругами з КНБ (кубічного нітриду бору) на верстатах з числовим програмним управлінням (ЧПУ). Тим більше, коли необхідно вибрати рішення, що відповідає багатьом цілям, які суперечать одна одній. У статті представлені результати дослідження багатокритеріального прийняття рішень (БКПР) щодо шліфування кругами з КНБ деталей циліндричної форми на фрезерних верстатах з ЧПУ. У роботі застосовувалися три методи БКПР, включаючи TOPSIS (метод упорядкованої переваги через подібність до ідеального рішення), MAIRCA (мультиаттрибутний порівняльний аналіз реального та ідеального) і EAMR (оцінка методом зонального ранжування). Крім того, для визначення вагових коефіцієнтів критеріїв використовувалися методи MEREC (метод, заснований на ефектах видалення критеріїв) та Entropy (ентропії). Також для планування експерименту, що має чотири вхідних фактори, включаючи глибину різання, швидкість обертання шпинделя, швидкість подачі та діаметр круга був використаний метод Тагучі з ортогональною матрицею L18 (6^1+3^3). В якості відповідних даних були обрані два критерії, включаючи шорсткість поверхні (ШП) і швидкість знімання матеріалу (ШЗМ). Вибір даних критеріїв обумовлений тим, що ШП та ШЗМ є двома дуже важливими вихідними факторами у процесі механічної обробки, а також шліфування кругами з КНБ на верстаті з ЧПУ. Зокрема, ці два критерії завжди суперечать один одному. Малі вимоги до ШП вимагатимуть невеликих значень швидкості подачі та глибини різання, що призведе до скорочення ШЗМ. За результатами дослідження було оцінено застосування різних методів для БКПР. Крім того, були дані рейтинги альтернативних рішень відповідно до методів БКПР. Також було знайдено найкраще альтернативне рішення, що гарантує як мінімальну ШП, так і максимальну ШЗ