Optimization Of Internal Structure Research Articles

Internal structure optimization for noise reduction in next-generation blower silencers

Internal structure optimization for noise reduction in next-generation blower silencers

Innovative Cellular Insulation Barrier on the Basis of Voronoi Tessellation-Influence of Internal Structure Optimization on Thermal Performance.

The optimization of structure and thermal properties in 3D-printed insulation materials remains an underexplored area in the literature. This study aims to address this gap by investigating the impact of 3D printing on the thermal properties of manufactured cellular composites. The materials studied were closed-cell foams with a complex cell structure based on the Voronoi cell model, manufactured using incremental technology (3D printing). The influence of the cellular structure of the composite, the type of material used, and the number of layers in the composite structure on its thermal properties, i.e., thermal conductivity coefficient, thermal resistance, and coefficient of heat transfer, was analyzed. Samples of different types of thermosetting resins, characterized by different values of emissivity coefficient, were analyzed. It was shown that both the type of material, the number of layers of the composite, and the number of pores in its structure significantly affect its thermal insulating properties. Thermal conductivity and permeability depended on the number of layers and decreased up to 30% as the number of layers increased from one to four, while thermal resistance increased to 35%. The results indicate that material structure is key in regulating thermal conduction. Controlling the number of cells in a given volume of composite (and thus the size of the air cells) and the number of layers in the composite can be an effective tool in designing materials with high insulation performance. Among the prototype composites produced, the best thermal performance was that of the metalized four-layer cellular composites (λ = 0.035 ± 0.002 W/m·K, Rc = 1.15 ± 0.02 K·m2/W, U = 0.76 ± 0.01 W/m2·K).

Study on optimization characteristics of methanol combustion cooker based on porous media

This research initially presents an internal structure optimization technique through numerical investigation with the intention of addressing the issues of unstable and poorly adjustable combustion flame of porous media methanol furnace. The entire premixed combustion technology and the flue gas waste heat evaporation technology are then combined in a combustion technology that is based on this stove structure. As a result, this resolves substantially the issues with methanol stove tempering, misfire, and uneven temperature. The fully premixed methanol cooker was eventually created and put into wide production. According to the findings, the flow rate was between 0.25 and 0.7 m/s before the cooker structural improvement and around 0.45 m/s after. More crucially, by eliminating the low temperature zone of approximately 300 °C and raising the temperature to about 500 °C, the temperature field at the cooker's exit porous medium was much improved. Additionally, the methanol cooker in the typical diffusion combustion mode was outperformed by the full premixed combustion technology and flue gas waste heat evaporation technology in this trial in terms of complete fuel combustion with no pollutant emissions. The study's findings indicate that the cooker's overall thermal efficiency is 68.2%, which has clear financial benefits.

Structural Optimization of the Main Bearing in a Tunnel Boring Machine Considering Clearance

Abstract An optimal design method for the main bearing of a tunnel boring machine is proposed. In this method, the fatigue life is used as the objective function. Structural parameters, including clearance, are considered as design variables. First, a quasi-static model of the main bearing and a calculation model of the fatigue life are established. The correctness of the theoretical method is verified by comparing it with the calculation results of the finite element method. Next, the influence of clearance on the load-carrying performance under external loads is analyzed. There is an optimal negative clearance for the axial loaded and radial rows. With the increase in the external loads, the optimal negative clearance gradually decreases. The variation laws of the load-carrying performance for the axial loaded and supporting rows affected by axial clearance mainly depend on the bias load degree of the main bearing. Finally, based on the optimal design model of the main bearing, the optimal internal structure is obtained using the genetic algorithm. The optimized fatigue life is improved by 92.2%. The load-carrying performance of the optimal main bearing has also been significantly enhanced compared to the initial design. Therefore, the proposed optimization method provides a practical approach to the main bearing design.

Temporal and Spatial Changes and Trend Predictions of Forest Carbon Sequestration Efficiency in China Based on the Carbon Neutrality Goal

Forestry’s high-quality development is crucial for China’s sustainable ecological, economic, and social progress. To elevate the efficiency of carbon sequestration in forestry, continuously improve the increment of carbon sinks, and contribute to achieving carbon neutrality, it is crucial to accurately assess the level of carbon sequestration efficiency in China’s forestry and explore its long-term evolution trend. In this paper, a super-efficiency SBM model, which combines the SBM model with the super-efficiency method and considers the relaxation variables, was selected to evaluate the forestry carbon sequestration efficiency of 31 provinces in China; likewise, the temporal development features of the efficacy of Chinese forests in sequestering carbon were examined using the nuclear density estimation method. Secondly, the study constructed traditional and spatial Markov probability transfer matrices to further explore the spatiotemporal evolution of carbon sequestration efficiency within Chinese forestry. Finally, combined with the Markov chain infinite distribution matrix, the future trajectory of carbon sequestration efficiency in China’s forestry was scientifically forecasted. The findings indicate that: (1) The average carbon sequestration efficiency of forestry in China showed a stable increase with fluctuations and reached the optimal state in 2018. The carbon sequestration efficiency level of various forest regions was always portrayed as southwest forest region > southern forest region > northeast forest region > northern forest region. From 2003 to 2018, there were significant differences in forestry carbon sequestration efficiency among provinces. The distribution of forestry carbon sequestration efficiency exhibited a “three-pillar” distribution pattern with Xizang, Zhejiang, and Heilongjiang as the core, and the marginal regions continuously promoted the carbon sequestration efficiency to the inland. (2) The type of transfer of forestry carbon sequestration efficiency in China is stable, and it is difficult to achieve cross-stage transfer in the short term. Moreover, the forestry carbon sequestration efficiency of each province tended to converge to a high (low) level over time, showing a “bimodal distribution” of low efficiency and high efficiency, indicating the existence of the obvious “club convergence phenomenon”. (3) Forecasting from a long-term evolution trend perspective, the outlook for the future evolution of forestry carbon sequestration efficiency in China is optimistic, and the overall trend was concentrated in the high-value area. Therefore, future forestry development in China should contemplate both internal structure optimization and coordinated regional development. Attention should be placed on forestry carbon sequestration’s role while considering the distinctive endowments of each region and developing reasonable, differentiated, and collaborative forestry management strategies.

Tuned tandem mass dampers-inerters for suppressing vortex-induced vibration of super-tall buildings

Modern super-tall buildings with rectangular floor shapes are vulnerable to significant vibrations due to the vortex shedding effect formed around structural edges. Tuned tandem mass dampers-inerters (TTMDI) is extended in this study to suppress vortex-induced responses of super tall buildings for occupant comforts. The optimal TTMDI tuning problem for a 400 m super tall building exposed to crosswind loads is solved through frequency-domain analysis. Meanwhile, the control performance of TTMDI is explored and contrasted with that of the tuned mass damper (TMD), tuned tandem mass dampers (TTMD) and tuned mass damper‐inerter (TMDI) from various perspectives. A crosswind-resistant design framework of the TTMDI equipped super-tall building system is then devised to meet comfort requirements. Finally, results are further assessed in the time -domain using a virtual real time hybrid simulation (VRTHS) system based on the proposed hybrid model predictive controller. It is found that there are several optimal inertance coefficient redistribution points (i.e. R points) in the design process and the R points have a great impact on the optimal internal structure of TTMDI. Results clearly demonstrate that TTMDI has better effectiveness and robustness than TMD, TTMD, and TMDI. Moreover, the total demand for total damping coefficients of TTMDI is significantly smaller than TMDI after the R points, indicating that it is easier to implement in engineering practices.

Evolutionary Mechanism of Coal Breaking by High-Pressure Water Jets Based on Numerical Simulation

Currently, coal bed methane (CBM) resources are in urgent need of development to alleviate the problem of resource constraints. This paper proposes a new method for detecting CBM gas by using the electroluminescence optical properties of the material to establish an electro-luminescence analysis method and the effect of CBM gas on the electro-luminescence intensity of nanomaterials to explore the electro-luminescence properties of nanomaterials and their influencing factors. In this paper, we investigate the high-pressure water jet drill bit for coal rock crushing by theoretical analysis, numerical simulation and rock breaking and punching tests, from the mechanism of coal rock crushing by jet, drill bit structure design, drill bit internal structure optimization and drilling and punching tests. By introducing acoustic emission technology, online monitoring of the coal seam crushing process was achieved. Physical tests and numerical simulations focusing on high-pressure water jet impact studied the crushing mechanism and damage characteristics of concrete under high-pressure water jet impact, improved the accuracy and safety of high-pressure water jet crushing technology, and investigated the crushing process of concrete and the damage distribution near the erosion hole. The extraction of CBM through very small radius radial drilling technology is one of the main trends in current exploration and development. The core component of radial drilling technology is the water jet bit, which has a decisive influence on the drilling efficiency and extraction results of radial drilling technology. Among many types of jet bits, the high-pressure water jet bit has the advantages of stability and reliability, strong drilling capacity, etc. It is suitable for the technical requirements of radial drilling, but the research on the mechanism of coal rock fragmentation and its flow field characteristics needs further study.

Models for IMPATT Diode Analysis and Optimization

Some of nonlinear models for high-power pulsed IMPATT diode simulation and analysis is presented. These models are suitable for the analysis of the different operational modes of the oscillator. Its take into account the main electric and thermal phenomena in the semiconductor structure and the functional dependence of the equation coefficients on the electrical field and temperature. The first model is a precise one, which describes all important electrical phenomena on the basis of the continuity equations and Poisson equation and it is correct until 300 GHz. The second approximate mathematical model suitable for the analysis of IMPATT diode stationary operation oscillator and for optimization of internal structure of the diode. This model is based on the continuity equation system solution by reducing the boundary problem for the differential partial equations to a system of the ordinary differential equations. The temperature distribution in the semiconductor structure is obtained using the special thermal model of the IMPATT diode, which is based on the numerical solution of the non-linear thermal conductivity equation. The described models can be applied for analysis, optimization and practical design of pulsed-mode millimetric IMPATT diodes. Its can be also utilized for diode thermal regime estimation, for the proper selection of feed-pulse shape and amplitude, and for the development of the different type of complex doping-profile high-power pulsed millimetric IMPATT diodes with improved characteristics.

Toward Long-Life Aqueous Zinc Ion Batteries by Constructing Stable Zinc Anodes.

Aqueous zinc-ion batteries (AZIBs) with high safety and low cost are considered to be one of the alternatives to Li-ion batteries. In recent years, AZIBs have become a research hotspot, mainly focusing on the research of cathode, anode and electrolyte. Although many efforts have been made in cathode materials, their low specific capacity and poor cycle life remain unsolved. In fact, side reactions of zinc metal anodes, such as dendrite growth, zinc corrosion, and hydrogen evolution reactions (HER), are also the main factors restricting the electrochemical performance of AZIBs. In this review, we first discuss the fundamental of these adverse reactions. Then, the various solution strategies are summarized based on advanced materials and structural design. It includes surface modification and the internal structure optimization of Zn electrodes, the regulation of electrolytes and separators. Finally, we propose the future challenges and development prospects of zinc anode.

Study on internal structure optimization of drying Chamber of Sludge drying equipment

Aiming at the problem of uneven distribution of velocity field in the drying chamber of JKFF series low-temperature closed cycle sludge drying equipment, the influence of internal structure change of drying chamber on air distribution was studied by numerical simulation. Fluent software is used for simulation, through the analysis of three factors affecting the internal structure of the oven, such as the position of the blower, the spacing of the mesh belt layer and the size of the aperture of the nylon mesh belt. The results show that it is better to put the air blower inside the heat pump than to put the air blower outside the bottom of the oven. When the spacing between the second and third layers is 240mm, the overall air distribution in the drying room is the best; By comparing and analyzing 9 combined working conditions of mesh belt aperture size, it is concluded that when the aperture size of the first and second layer mesh belt is 2mm×2mm, and the aperture size of the third layer mesh belt is 1.5mm×1.5mm, the air distribution in the oven reaches the best state.

Internal Structure Optimization to enhance the Thermal Performance of an Air-cooled Lithium-ion Battery Pack

Internal Structure Optimization to enhance the Thermal Performance of an Air-cooled Lithium-ion Battery Pack

Design and Psychometrics of a Tool for Assessing Clinical Skills of Using "Stuttering Severity Instrument-Fourth Edition

Background and Objectives: The Severity of Stuttering Instrument-fourth edition (SSI-4) form can be used to assess the severity of stuttering. In this study, in order to increase students’ competence and objectively assess their clinical skills, the validity and reliability of the DOPS test in assessing the clinical skills of speech therapy students in using the SSI-4 form were assessed. Methods: This study was a non-interventional descriptive study conducted in the School of Rehabilitation Sciences. Nineteen students were selected by the census method. An evaluation checklist related to the DOPS method was prepared. After obtaining the consent and training of students and examiners on the implementation of the DOPS assessment method, the student’s work was observed by the examiners and rated, and then the student’s strengths and weaknesses were given feedback. Results: The results showed that the questions are related to the measured subject and have high face validity. The content validity index was more than 0.9, and the content validity ratio was more than 0.6. The results confirmed the test's reliability and indicated the optimal internal structure of the test and its structural validity. Conclusion: According to this study, the use of the DOPS test to objectively assess the clinical skills of speech therapy students in the assessment of stuttering is appropriate and according to the results, DOPS has appropriate validity and reliability and this test can be used clinically.

Traditional treatment approach for disordered articulation of sounds: evaluating clinical skills of Speech Language Pathology students by Direct Observation of Procedural Skills

Background and Objectives: One of the common disorders in Speech Language Pathology (SLP) is speech sound disorder. To increase students’ competence and objectively evaluate their clinical skills, we used the Direct Observation of Procedural Skills (DOPS) test in a clinical setting and examined its validity and reliability Methods: This research is a non-interventional descriptive study. Twenty students who participated in this study were selected by the census method. Traditional treatment approach skill for speech sound disorder was selected. Then an evaluation checklist of DOPS was prepared. After obtaining the consent of students and professors, they entered the study. Two professors observed the work of all student during the procedure on a real patient. Results were recorded in a checklist, and feedback was given to the students about their strengths and weaknesses. Results: The content validity index of the DOPS test was more than 0.8, and its content validity ratio was more than 0.62. The correlation coefficients of questions indicate the optimal internal structure of the test and its structural validity. The results showed that the test questions were related to the predetermined subject. Results confirmed high face validity. The obtained Cronbach α coefficient (0.865) confirmed DOPS reliability. There was a significant inter-rater correlation coefficient (0.901) between evaluators (P<0.001). Conclusion: According to the study, the use of DOPS for objective assessment of clinical skill has validity and reliability. This test can be used to evaluate the clinical work of SLP students, provide feedback, identify their strengths and weaknesses, and improve them.

Analysis of Electrical and Thermal Models for Pulsed IMPATT Diode Simulation

Some nonlinear models are presented for modeling and analyzing IMPATT high-power pulse diodes. These models are suitable for analyzing different operating modes of the oscillator. The first model is a precise one, which describes all important electrical phenomena on the basis of the continuity equations and Poisson´s equation, and it is correct until 300 GHz. The second approximate mathematical model suitable for the analysis of IMPATT diode stationary operation oscillator and for optimization of internal structure of the diode. The temperature distribution in the semiconductor structure is obtained using the special thermal model of the IMPATT diode, which is based on the numerical solution of the non-linear thermal conductivity equation. The described models can be applied for the analysis, optimization and practical design of pulsedmode millimetric IMPATT diodes. It can also be used to evaluate the thermal behavior of diodes, to correctly select the shape and amplitude of a supply pulse, and to design various types of high-power pulsed millimeter IMPATT diodes with a complex doping profile with improved characteristics.

Industrial Structure Effect of China’s Urban Air Quality Improvement：A Natural Experiment of COVID-19

Promoting the adjustment and optimization of industrial structure and promoting the transformation of traditional extensive production mode and consumption mode to green and low-carbon is an important embodiment of the concept of innovation and green development, and an important way to realize the work of “carbon emission peak, carbon neutralization”. Identifying the impact of industrial structure characteristics on environmental pollution and exploring how to effectively reduce the impact on the environment by industrial structure transformation and upgrading are an important basis for precise policy implementation and realizing the synergistic effect of industrial structure adjustment and environmental governance. In response to the inadequacy of previous studies in dealing with the endogenous problem between industrial structure and environmental pollution, based on the weekly air quality index（AQI）of prefecture-level cities in China during nearly three months around the Spring Festival in 2019 and 2020, this paper takes COVID-19-induced production shutdown as a natural experiment to study the impact of industrial structure on air quality and identify the major industries that cause air pollution with the generalized DID method. The study finds that: The impact on air quality mainly comes from the secondary industry. In the shutdown environment, the AQI decreases by 0.470% when the proportion of secondary industry in GDP increases by 1% compared with the same period of last year. The impact of the internal subdivisions of the secondary industry on air quality also presents great differences, among which the manufacturing industry has the greatest impact, and the influence coefficient of light industry in the manufacturing industry is higher than that of equipment manufacturing industry and energy chemical industry. The impact of mining and construction on air pollution is not significant. Life supply industry such as water, electricity, gas and so on shows no significant impact on air quality improvement as increased demand for living during the epidemic replaced reduced industrial demand for work. At the same time, this paper also finds that different industries have great differences in the path dependence on air quality, and the production process of the secondary industry has a relatively higher contribution to pollution. Within the manufacturing industry, light industry is relatively more affected by commuting factors, while energy and chemical industry is more affected by production process factors.Based on the above conclusions, this paper puts forward some suggestions: First, from the perspective of industrial structure adjustment to achieve “carbon emission peak, carbon neutralization”, it is necessary to pay attention to the importance of the internal structure adjustment of the secondary industry, and strengthen the prevention and control of the manufacturing industry, especially light industry, energy and chemical industry, etc. Second, the adjustment of industrial structure and environmental governance need to vary from city to city, fully considering the economic development stages and geographical and climatic conditions. Third, while promoting the “return” of the manufacturing industry, especially the high-end manufacturing industry, we should always adhere to the concept of internal structure optimization, and keep the bottom line of high-quality development when balancing industrial development and environmental governance. This paper provides a practical basis for realizing the industrial structure adjustment of “carbon emission peak, carbon neutralization”.

Novel Flat-Plate Photobioreactor with Inclined Baffles and Internal Structure Optimization to Improve Light Regime Performance

A novel flat-plate photobioreactor (FPPBR) with inclined baffles (IBs) was developed and used for high-density algae cultivation. The internal structure of the bioreactor was optimized using comput...

ВИБІР ОПТИМАЛЬНОЇ СТРУКТУРИ ПРИХОВАНИХ ШАРІВ ШТУЧНОЇ НЕЙРОННОЇ МЕРЕЖІ ДЛЯ АНАЛІЗУ ЕФЕКТИВНОСТІ ЕНЕРГОСПОЖИВАННЯ

A method for optimal structure selection of hidden layers of the artificial neural network (ANN) is proposed. Its main idea is the practical application of several internal structures of ANN and further calculation of the error of each hidden layer structure using identical data sets for ANN training. The method is based on the alternate comparison of the expected result values and the actual results of the feedforward artificial neural networks with a different number of inner layers and a different number of neurons on each layer. The method afforces searching the optimal internal structure of ANN for usage in the development of "smart" house systems and for calculation of the optimal energy consumption level in accordance with current conditions, such as room temperature, presence of people, and time of the day. The usage of the presented method allows to reduce the time spent on choosing the effective structure of the artificial neural network at the initial stages of research and to pay more attention to the relationship between the input and output data, as well as to such important parameters of the ANN learning process, as a number of training iterations, minimal training error, etc. The software has been developed that allows to carry out the processes of training, testing, and obtaining the output results of the algorithm of the artificial neural network, such as the expected value of power consumption and operating time of each individual appliance. The disadvantage of the approach used in finding the optimal internal structure of the artificial neural network is that each subsequent structure is created on the basis of the most efficient of the previously created structures without analyzing other structures that showed worse results with fewer hidden layers. It was found that to improve the solution of this problem it is necessary to create a mechanism which will be based on the analysis of input data, output data, will analyze the internal relationships between parameters and will optimize the network structure at each stage using certain logical rules according to the results obtained in the previous step. It is established that this problem is a nonlinear programming problem that can be solved in the further development of this study.

Construct Validity of the Comprehensive Assessment of Psychopathic Personality (CAPP): Examining the Internal Structure and Generalizability of CAPP Self-Ratings Across Gender and Ethnicity.

The Comprehensive Assessment of Psychopathic Personality (CAPP) is a recently developed conceptual model of psychopathy designed to index the disorder across 33 personality traits. Although recent research has evidenced support for the CAPP model with respect to the convergent, criterion, and predictive validity of CAPP instruments, little work has examined the optimal internal structure and generalizability of the model and associated measures. The present study sought to elaborate on the construct validity and psychometric properties of the CAPP Lexical Self Rating Scale and determine the utility of the instrument across men and women, and individuals of Caucasian and East Asian descent. Within a large sample of self-identified offenders (N = 1,414), we found strong support for a three-factor model comprising domains reflecting interpersonal dominance, behavioral disinhibition, and deficient emotional attachment. Analyses examining the generalizability of the model provide further insight into its applicability for diverse populations.

On the potential use of basalt waste as mineral fillers

Producing present-day constructional materials on mineral binders is directly connected to the use of micro- and ultra-disperse technogenic modifying agents. They allow to obtain the maximum particle-particle packing in composition, provide rational raw mix design, contribute to structure formation process. The present article is devoted to the investigation of searching the most rational solution for the problem of basalt waste utilization, with the basalt waste being the valuable secondary raw material resource. The studies have shown that it is possible to use basalt dust as admix to gypsum composites. The basalt waste, by changing the composition grain-size distribution, provides the better particle-particle packing both for finegrained and coarse waste fractions, thus having positive effect on modified gypsum rock structure. Optimization of internal structure also contributes to the increase of gypsum rock strength properties. The obtained gypsum composite can be profitably employed for manufacturing small-piece walling gypsum materials by casting process.

Generalized combined nonlinear adaptive filters: From the perspective of diffusion adaptation over networks

Combination of nonlinear adaptive filters (CNAF) is gaining popularity as an effective solution to enhance the filter performance by addressing compromises with respect to parameter and structure settings. However, most existing algorithms study the optimal choice of different filters while neglecting the internal structure optimization of filters. This limitation restricts the performance of CNAF. In this work, we propose a new scheme of the CNAF from the perspective of diffusion adaptive over network. Instead of combining the filters in a parallel manner, we consider to organize the candidate filters in a network manner. Specifically, a network with two subnetworks is constructed, and nodes in each subnetwork serve as linear adaptive filters and nonlinear adaptive filters respectively. A generalized CNAF (GCNAF) is obtained by linking the nodes of the network. The proposed GCNAF allows information exchange and sharing among nodes, so as to enhance the performance of the combined filters. As a result, search direction of each filter is also adjusted by combining those of other filters via the diffusion over networks. We show some representative, state-of-the-art combined adaptive filters are special cases of the proposed framework. Simulations with an acoustic problem demonstrate the effectiveness of the proposed GCNAF.