Part Of Structure Research Articles

The Effect of Alumina-Rich Spinel Exsolution on the Mechanical Property of Calcium Aluminate Cement-Bonded Corundum Castables

This study investigates the effect of the exsolution behavior of alumina-rich spinel on the formation and distribution of CA6 (CaAl12O19) in corundum castables bonded with calcium aluminate cement. In this study, alumina-rich spinel is substituted for tabular corundum in the same proportions and grain size. The matrices after curing were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The phase composition and microstructure of the matrices containing alumina-rich spinel were analyzed after firing at 1600 °C. These results showed that the addition of alumina-rich spinel significantly improved the mechanical strength of the castables. This improvement was attributed to the alumina produced by spinel exsolution during firing at 1600 °C, which reacted in situ with CA2 (CaAl4O7) to form CA6. CA6 connects the different particles and forms an interspersed interlocking structure within the spinel. The CA6-MA interspersed interlocking structure replaces part of the CA6-Al2O3 structure and significantly improves the mechanical strength of the castables.

An Economic Theory with a Formal-Econometric Test of Its Empirical Relevance

The paper contains five parts—a theory about entrepreneurial choice under uncertainty, a formal econometric structure for a test, the test, an appraisal of the test, and a description of the data generating process. Here, an entrepreneur is an individual who manages a firm that produces one commodity with labor, an intermediate good, and capital. He pays dividends to shareholders, invests in bonds and capital, and has an n-period planning horizon. Conditioned on the values of current-period prices, the entrepreneur aims to maximize the expected value of a utility function that varies with the dividends he pays each period and with his firm’s balance sheet variables at the end of the planning horizon. The test comprises a family of trials of theorems that I derive from the axioms of the theory part of the formal econometric structure. In the test, the theorems are appraised for their empirical relevance in an empirical context, where each one of a random sample of four hundred entrepreneurs has chosen the first-period part of his optimal n-period expenditure plan. My formal econometric arguments demonstrate that the theorems pass all the trials. At the end, I show that my formal econometric results imply that the theory is empirically relevant.

Some Aspects of Patriotic Education of Future Teachers

The importance of patriotic education of future teachers in the education system of Kyrgyzstan is considered. For centuries, the love of the people for their homeland, the protection of their interests and unity, and respect for the heritage of their ancestors have formed the basis of patriotic feeling. In most post-Soviet countries, patriotism has become an important part of the political discourse in order to form a national and civic identity. The formation of the Kyrgyz nation - a single civic nation uniting representatives of various ethnic groups living in Kyrgyzstan, should be really strengthened in their consciousness through feelings of love for their country, pride in it, and patriotism. Formation of interest in love for the Kyrgyz land, knowledge of its ancient history is one of the main tasks of modern education. Patriotism is an essential structural and integral part of the national idea, culture and science. Fostering a sense of patriotism is very important for the future of Kyrgyzstan. Patriotic education of future teachers helps to convey national values to the younger generation. Education of patriotic youth is a living, responsible process.

Narrative Review and Guide: State of the Art and Emerging Opportunities of Bioprinting in Tissue Regeneration and Medical Instrumentation

Three-dimensional printing was introduced in the 1980s, though bioprinting started developing a few years later. Today, 3D bioprinting is making inroads in medical fields, including the production of biomedical supplies intended for internal use, such as biodegradable staples. Medical bioprinting enables versatility and flexibility on demand and is able to modify and individualize production using several established printing methods. A great selection of biomaterials and bioinks is available, including natural, synthetic, and mixed options; they are biocompatible and non-toxic. Many bioinks are biodegradable and they accommodate cells so upon implantation, they integrate within the new environment. Bioprinting is suitable for printing tissues using living or viable components, such as collagen scaffolding, cartilage components, and cells, and also for printing parts of structures, such as teeth, using artificial man-made materials that will become embedded in vivo. Bioprinting is an integral part of tissue engineering and regenerative medicine. The addition of newly developed smart biomaterials capable of incorporating dynamic changes in shape depending on the nature of stimuli led to the addition of the fourth dimension of time in the form of changing shape to the three static dimensions. Four-dimensional bioprinting is already making significant inroads in tissue engineering and regenerative medicine, including new ways to create dynamic tissues. Its future lies in constructing partial or whole organ generation.

Method and Experimental Research of Transmission Line Tower Grounding Body Condition Assessment Based on Multi-Parameter Time-Domain Pulsed Eddy Current Characteristic Signal Extraction

Pole tower grounding bodies are part of the normal structure of the power system, providing relief from fault currents and equalizing overvoltage channels. They are important devices; however, in the harsh environment of the soil, they are prone to corrosion or even fracture, which in turn affects the normal utilization of the transmission line, so accurately assessing the condition of grounding bodies of the power grid is critical. To assess the operational status of a grounding body in a timely manner, this paper proposes a multi-parameter pulsed eddy current (PEC) time-domain characteristic signal corrosion classification method for the detection of the state of a pole tower grounding body. The method firstly theoretically analysed the influence of multi-parameter changes on the PEC response time-domain feature signal caused by grounding body corrosion and extracts the decay time constant (DTC), and the decay time constant stabilization value (DTCSV) and time to stabilization (TTS) were obtained based on the DTC time domain characteristics for describing the corrosion of the grounding body. Subsequently, DTCSV and TTS were used as inputs to a support vector machine (SVM) to classify the corrosion of the grounding body. A simulation model was constructed to investigate the effect of multiparameter time on the DTCSV and TTS of the tower grounding body based on the single-variable method, and the multiparameter time-domain characterization method used for corrosion assessment was validated. Four defects with different corrosion levels were classified using the optimized SVM model, with an accuracy rate of 95%. Finally, a PEC inspection system platform was built to conduct classification tests on steel bars with different degrees of corrosion, and the results show that the SVM classification model based on DTCSV and TTS has a better discriminatory ability for different corrosive grounders and can be used to classify corrosion in the grounders of poles towers to improve the stability of power transmission.

Radiation-assisted tailoring of swelling behavior and water retention of Na-CMC/PAAm hydrogels for enhancing Beta Vulgaris under drought stress

This study investigates the negative impact of climate change on water resources, specifically water for agricultural irrigation. It describes how to optimize swelling, gel properties and long-term water retention capacities of Na-CMC/PAAm hydrogels for managing drought stress of Sugar beet plants through techniques such as changing the composition, synthetic conditions and chemical modification. Gamma radiation-induced free radical copolymerization was used to synthesize superabsorbent hydrogels using sodium carboxymethyl cellulose (Na-CMC) and acrylamide (AAm). The study also explored how varying Na-CMC/AAm ratio and radiation dose influence their swelling behaviour, gel fraction, and water retention. FTIR showed that CMC and PAAm components are part of the hydrogel structure. The equilibrium swelling reached a maximum value of ~ 500 g/g at a Na-CMC/AAm ratio of 60/40. High content of AAm reduced swelling because it caused increased hydrophobicity while high radiation doses up to 50 kGy increased crosslinking resulting in improved but limited swelling from 65 to 85 (g/g). After the second cycle, KOH modification reached maximum swelling capacity by introducing anionic carboxylate groups up to 415 (g/g). SEM images revealed uniform pores in an unmodified scaffold while larger cavities were formed upon modification facilitating Water absorption. Surprisingly, the improved hydrogels retained more water: about 75% even after 16 days as opposed to a 50% drop within five days in the case of unmodified ones. This hydrogel significantly enhanced shoot length by 18%, root length by 32%, fresh weight shoot by 15%, and dry weight shoot by 15% under severe drought conditions. As a result, yield increased by 22%, proteins went up by 19%, and carbohydrates rose by 13%. Leaf chlorophyll content increased with a corresponding decline in stress enzymes indicating decreased oxidative damage. This eco-friendly Na-CMC/PAAm-based hydrogel seems to have potential use for addressing water scarcity and agricultural challenges.

Determining the quantity and quality of wood recovered from building demolitions to enable effective allocation

The goal of this study was to determine the quantity and quality of wood extracted from the structural parts of wooden buildings to facilitate the most appropriate allocation of the material. An additional aim was to provide a reliable and consistent characterisation procedure for recovered wood, according to its physical characteristics, such as dimensions, the presence of cracks etc. From a sample of recovered wood collected from the demolition of a wooden building in Espoo, Finland, it was found that around 30% of the total volume of material could be recovered for repurposing or remanufacturing into solid wood products, provided structural integrity can be ensured. The samples of recovered wood were relatively short compared to virgin timbers, averaging 88 cm. Further, it was determined that removing metal contaminants does not necessarily improve material recovery, because cracks, wane, warping, as well as machining the recovered wood to standard dimensions, impact material recovery the most.

A novel sensor-independent convolutional neural network for structural damage detection：illustrated by a case study on gantry crane

Structural damage detection is a critical technology for ensuring the safety of engineering structures. In recent years, intelligent structural damage detection algorithms based on machine learning have garnered widespread attention globally, thanks to their efficient and reliable detection performance. However, existing damage detection methods largely depend on the use of sensors, which not only increases operational and maintenance costs but also limits the applicability of these methods—especially in parts of structures where sensors are difficult to install. To overcome this barrier, this paper introduces a novel sensor-independent convolutional neural network (CNN) approach for predicting the maximum response of structures under seismic excitation. This method utilizes IDA method to collect a large number of samples (these samples have been uploaded to Mendeley Data for reference). It employs innovative data processing and grouping methods for feature alignment as well as the division of the test and training sets. By automatically extracting the signal characteristics of seismic excitation and optimizing feature combinations through multi-layer fusion, this method achieves high-precision and robust prediction without relying on sensors. To validate the effectiveness of this method, this study conducted a performance evaluation on a typical gantry crane metal structure. The results show that the proposed sensor-independent CNN algorithm achieves high-precision structural response prediction, with over 99% accuracy for peak responses, demonstrating the robustness and reliability of the model. It also performs excellently in key metrics such as root mean square error, error bias, and learning rate progression, making it a reliable and cost-effective solution for real-time seismic damage detection.

Formulation of the extended plane wave expansion for in‐plane and out‐of‐plane vibrations in viscoelastic phononic thin plates under a constant temperature field

AbstractIn this study, we develop an extended plane wave expansion method to determine the complex elastic band gaps for both in‐plane and out‐of‐plane vibrations in a viscoelastic phononic crystal (PnC) thin plate model under a constant temperature field. The periodic structure of the thin plate comprises a unit cell (UC) consisting of an epoxy matrix and circular steel inclusions. In this configuration, we consider the viscoelastic effects described by the generalized Maxwell model arising from the epoxy matrix. Furthermore, we incorporate thermal effects in the UC, accounting for the linear dependence of the Young's modulus on the temperature of the epoxy matrix, assuming the absence of heat flow in the dimensions of the UC. We present a band structure illustrating the displacement of the real and imaginary parts of the complex band structure for evanescent waves arising from the viscoelastic PnC thin plate, considering both in‐plane and out‐of‐plane vibrations.

Manfaat Kecerdasan Buatan pada Proses Belajar Mengajar di Pendidikan Tinggi

This research aims to determine the benefits of using artificial intelligence in the teaching and learning process in higher education. The contribution of computer science, especially artificial intelligence, to the field of education is very much felt. From robotic teaching to the emergence of automated systems for answer sheet analysis, artificial intelligence always helps lecturers and students. This study also investigates the educational implications of emerging technologies on how students learn and how the teaching and learning process in higher education is developing. Data analysis is carried out comprehensively on various analytical developments applied worldwide such as computer science techniques applied to the education sector so as to summarize and highlight the role of artificial intelligence in the teaching and learning process. The latest technological advances and the increasing speed of application of new technologies in higher education are explored to predict the nature of higher education today and in a world where artificial intelligence becomes part of the higher education structure. The results of the study indicate several challenges for higher education institutions and student learning in adopting this technology for the teaching and learning process, support from students, and administration and the need to explore further research directions.

Microstructure homogenization and strength-ductility synergy improvement of the hybrid additive manufactured dual-phase titanium alloy by sub-critical annealing

ABSTRACT This study employed the effect of sub-critical annealing heat treatment on the microstructure and anisotropy of the hybrid additive manufactured TC11 alloy. The results demonstrate that after sub-critical annealing, a gradient microstructure with the gradual changes in the morphology and content of primary α phases from the laser deposition zone to the substrate zone was formed. Moreover, the tensile anisotropy of the hybrid manufactured specimens was substantially reduced. In particular, when loading along to the deposition direction, the ultimate tensile strength of the heat-treated hybrid manufactured specimen was 1062 MPa, increased by 8.5%. And when loading perpendicular to the deposition direction, the elongation can reach 13.0%, increased by 86% compare to the as-deposited sample. These findings would also shed new insights for the modification of graded structural parts prepared by the hybrid manufacturing technique, laser additive repair and other methods.

МЕТОДИКА ОБОСНОВАНИЯ ХАРАКТЕРИСТИК ТЕПЛОИЗОЛЯЦИОННОГО МАТЕРИАЛА В СОСТАВЕ ОГРАЖДАЮЩЕЙ КОНСТРУКЦИИ С ИСПОЛЬЗОВАНИЕМ СРЕДСТВ КВАДРАТИЧНОГО ПРОГРАММИРОВАНИЯ

Abstract: Relevance of the research is connected to the importance of the problems related to the determination of the characteristics for structural solutions used in the construction or reconstruction of buildings and structures (taking into account the indicators of energy and economic efficiency), as well as the relatively low practical significance of the relevant scientific developments. Problem statement. It is necessary to determine the most preferred variant (model) of heat-insulating material used as an additional layer in the wall structure on the basis of the criteria related to the provided heat transfer resistance and the payback period of the corresponding design solution. Research aim. Development of tools for determination of the characteristics for thermal insulation material as part of wall structure within a residential building. Research tasks are the following: 1. Review and comparative analysis of scientific developments in the field of research. 2. Development of the procedure for determination of the characteristics for the heat-insulating material as part of the wall structure with the use of quadratic optimization tools. 3. Implementation of the developed procedure on a practical example. Results. Procedure for determination of the characteristics for the heat-insulating material as part of the wall structure with the use of quadratic optimization tools has been developed. The procedure has been implemented using a practical example, and the received results have been analyzed. Findings. The results of the procedure’s implementation on a practical example confirm the high practical significance of the developed tool. Thus, quadratic optimization tools can be effectively used to solve the problem related to the determination of the characteristics for heat-insulating material as part of an wall structure.

Development of High Strength Concrete for Structural Application in Asia

Due to its improved mechanical qualities and ability to reduce the size of structural parts, high-strength concrete (H.S.C.) has attracted much interest in structural engineering. This study article examines how high-strength concrete may be used in structural applications developed in Asia. The study's main objectives are to improve the mix design, add the appropriate admixtures, and evaluate the mechanical characteristics and durability of the resultant high-strength concrete. The development of High Strength Concrete (H.S.C.) material components for structural applications in Asia has been the subject of substantial research by several scholars. The findings of this study show that high-strength concrete breakthroughs and ground-breaking architectural icons have been built in Asia. For high-strength concrete to be used successfully and securely over the long term, proper mix design, quality control, and building techniques are essential.

Exploring Compactness and Dynamics of Apomyoglobin.

Hydrogen-deuterium exchange mass spectrometry (HDX-MS) approach has become a valuable analytical complement to traditional methods. HDX-MS allows the identification of dynamic surfaces in proteins. We have shown that the introduction of various mutations into the amino acid sequence of whale apomyoglobin (apoMb) leads to a change in the number of exchangeable hydrogen atoms, which is associated with a change in its compactness in the native-like condition. Thus, amino acid substitutions V10A, A15S, P120G, and M131A result in an increase in the number of exchangeable hydrogen atoms at the native-like condition, while the mutant form A144S leads to a decrease in the number of exchangeable hydrogen atoms. This may be due to a decrease and increase in the compactness of apoMb structure compared to the wild-type apoMb, respectively. The L9F and L9E mutations did not affect the compactness of the molecule compared to the wild type. We have demonstrated that V10A and M131A substitutions lead to the maximum and large increase correspondently in the average number of exchangeable hydrogen atoms for deuterium, since these substitutions lead to the loss of contacts between important parts of myoglobin structure: helices A, G, and H, which are structured at the early stage of folding.

Welding Pores Evolution in the Detector Bottom-Locking Structure Fabricated Using the Hybrid Pulsed Arc–Laser Method

The welding of the bottom-locking structure in a detector receptacle plays an essential role in ensuring the safety of nuclear equipment. A pulsed TIG–laser hybrid welding method is proposed to address the problem of welding pores in locking structural parts. The effects of the pulse frequency on the escape of porosity and of porosity on the mechanical properties of the hybrid welding joint were investigated. The results were compared to those of direct current (0 Hz), showing that the pulse frequency affects the stability of the arc. With an increase in pulse frequency, the grain size of the fusion zone gradually decreases, and the flow in the middle area of the molten pool increases. This subjects bubbles in the molten pool to a thrust force, which causes the bubbles to escape to the surface of the molten pool. Compared with 0 Hz, the tensile strength of the joint increased by 67%. This provides a new solution for obtaining reliable welded joints for the bottom-locking structure of detector storage tanks.

Расчет температурных полей на основе конечно-элементной модели процесса аддитивного синтеза изделия

The work is devoted to the creation of a hybrid finite element model of the process of additive synthesis of a product by the Wire Arc Additive Manufacturing/3D Metal Print method, supplemented by a block of wave strain hardening of the synthesized product. The main result obtained is the proposed original approach to the mathematical modeling of fundamentally new processes of synthesis and hardening of a wide range of products manufactured from various materials in the form of wire, which can be extended to the entire class of additive synthesis processes with periodic or post-processing. The main feature of the approach is the hybridization of calculation models, while, unlike known solutions, significant attention is paid to the processes of exchange and transmission of information between the models of synthesis and hardening processes. A distinctive feature of the hybrid model is the need for a periodic exchange of information on the geometric and temperature parameters of the synthesized areas at a specific point in time. The novelty of the hybrid model is in the application of coordinated approaches to solving thermal and mechanical problems in a three-dimensional formulation in the ANSYS environment, taking into account the natural dynamic heat flows that form in the synthesized product and the installation table modeled by the finite element method. Calculation of continuously changing dynamic temperature fields in the synthesized product with additional optimization and visualization capabilities is an important structural part of the model. The studies performed allowed us to identify a significant range of the ratio of the product and table volumes 30 ≤ Vс/Vи ≤ 100 and patterns in the formation of temperature fields when changing the table parameters.

On Selecting Indicators for SEM Models: Trade-Offs Among Variable Type, Quantity, and Quality

To study the dynamics among latent variables, researchers often use structural equation modeling (SEM). The real interest of SEM is often in the structural part, which explains the relationships among the latent variables. The indicators are peripheral; they exist because it is impossible to obtain the latent variables’ scores. Perhaps because the indicators are peripheral in developing substantive theories, how to choose indicators for SEM has received little attention in the literature. The attention has been largely drawn to model estimation and evaluation given a set of indicators, but the importance of indicators for the quality of model estimation has been overlooked. In this paper, we study the trade-offs among the variable types, quantity, and quality of indicators with respect to the quality of estimating structural-level model parameters. Better selections of indicators can substantially improve estimation quality without increasing the sample size. Using many lower-loading indicators is not necessarily inadvisable.

L2 German Word Order Preferences by Immigrant L1 Korean Speakers

Abstract This study examines the L2 German verb placement preferences in 58 Korean immigrant workers in Germany. The verb placement preferences are compared to predictions of Organic Grammar (Vainikka and Young-Scholten, 2011). Assuming an incremental, bottom-up morphosyntactic development, the theory predicts the possibility that L2 acquirers develop only partial clausal structures. Organic Grammar further proposes a two-tree approach of morphosyntactic development and predicts that main clauses with verb-second order (V2) are acquired before subordinate clauses with verb-final order (OV). To test these predictions, participants completed two production tasks. Results show a mixed picture. Some participants’ L2 clausal structure seems to have developed only partially, supporting the incremental approach. Regarding the predicted order of acquisition, however, some participants who showed robust use of targetlike subordination with OV, struggled with V2, preferring V3 instead. This suggests the need for a revision of the two-tree approach to incorporate the V3 preference.

Assessment on wire-arc additive manufactured high strength low alloy steel cylindrical component

Large structural parts are widely manufactured through wire-arc additive manufacturing (WAAM) due to its high deposition rate, flexibility, and low cost. There are a variety of industries where high strength low alloy (HSLA) steel is used, including naval, tool and die manufacturing, construction, and offshore structures. The present article examines the mechanical properties and microstructural evolution of a developed HSLA component. The microstructural analysis was done in the component’s top (TR) and bottom (BR) regions. It reveals almost similar microstructural constituents but with more polygonal ferrite in the TR and bainitic structure in the bottom, with acicular ferrite in both regions. The inclusions in both regions were characterized using energy-dispersive X-ray spectroscopy. This demonstrates that manganese (Mn), as a strong deoxidizer, reacts with oxygen and dissolves entirely within the inclusion, forming a Mn depletion zone. Additionally, grain coarsening was observed in the building direction. The average grain size in the TR and BR was 13.12 μm and 6.54 μm, respectively. Within the regions considered, only 2.47%, 4.06%, and 0.65% variations were observed between yield strength, ultimate tensile strength, and elongation to fracture.

Static analysis of stay cables under the varying chord strength of the cable failure inspection in cable-stayed bridges

Purpose of research. Bridge constructions are frequently subjected to harsh circumstances such as severe weather, earthquakes, traffic accidents, and even explosives. Bridge structures may lose some of their important structural parts (e.g., cables or piers) as a result of such intense external stresses, and further collapse is possible, as progressive collapse is often caused by the abrupt loss of one or more critical structural components. Cable-stayed bridges have very tiny crosssectional areas and are subjected to high loads. Such strong pressures can destroy anchoring zones due to large stress concentrations, resulting in cable loss. Bridges with cable stays must be thoroughly investigated for the danger of progressive collapse induced by cable loss scenarios. Suggests considering the most common cable failure scenarios throughout the design process. To evaluate the effect of cable loss, do a static analysis with a (DAF) of two. There are two primary ways for avoiding progressive collapse. First, adopt structural or non-structural measures to provide a high level of safety against localized collapse. Second, prevent failures from spreading by establishing a solid foundation that allows for local failures.Methods. Materials and methods. Damage to cables in the mathematical modeling of cable-stayed bridges. A continuous beam suspended from tension elements (cables) forms the basis of the conceptual model. His strength calculation plan is by comparing stiffness and flexibility matrices of intact and damaged systems. The stiffness matrix for an intact system is calculated using its reduced shape. The flexibility matrix is then calculated by inverting the reduced stiffness matrix. The conceptual model is interactive. As a result, the stiffness matrix is infinite. For direct analytical calculations, the parameter n is set as the ratio of the stiffness of the system ( = ), and a reduced form of the stiffness matrix is obtained to obtain an intact.Results. The secant module seems to give a very good approximation, since the error remains less than 1% for cables up to 300 m long and less than 2% for cables up to 750 m long. Russians Russian Bridge has a length of 135.77 meters and the longest cable is 579.57 meters, as a result, the error rate of cables on the Russian Bridge will remain less than 1% for some cables and less than 2% for some cables. Considering that the modulus of elasticity of the steel material of the cable is rarely known with an accuracy of more than 2-3%, it is obvious that the method for determining the secant modulus would be suitable for all practical purposes. The tangent module is often easier to use than the secant module, since it is only necessary to know the voltage of the cable in its initial state. On the other hand, the tangent module can lead to erroneous conclusions with a long cable length and a large traffic-to-idle ratio, as shown in Figure 8.Conclusion. The distance between two adjacent cables on modern bridges is significantly less than on older bridges. As a result, in the event of a car accident or explosion on the new bridge, several cables will fail. As a result, it was proposed that bridge designers take into account the rupture of all cables within a radius of 10 meters. Several studies have been conducted to find DAF in bridges. According to this study, having a father of two is not always safe. Although a recent study shows that the proposed DAD is safe for cable construction, that is, it is unsafe for structures of pylons or beams with negative moments.