Dimensional Adjustment Research Articles

Molecular dynamics investigation on the mechanical properties of a novel 2D carbon allotrope: Planar net-τ nanoribbon

This study is focused on investigating of the mechanical properties of a recently discovered two-dimensional carbon allotrope, known as planar net-τ, through molecular dynamics simulations. The planar net-τ is a unique and unexplored carbon configuration known for its intricate network of carbon atoms arranged in a planar lattice. The study aims to improve understanding of the mechanical properties of planar net-τ. This includes investigating parameters such as Young's modulus, fracture strain, ultimate strength, strain at ultimate stress, and the stress-strain curve. This study achieves this by deliberately manipulating of variables, such as introduction of vacancy defects, altering temperature, and dimensional adjustments. Vacancy defects in 2D carbon allotropes significantly impair their mechanical properties, reducing stiffness and increasing mechanical failure. Changes in dimensions further impact these properties through contraction, affecting strength and elasticity. These results highlight the anisotropic nature of these structures.

Optimization and mass transfer analysis under the ribs of multi-serpentine flow fields

This study aims to enhance the performance of Proton Exchange Membrane Fuel Cell (PEMFC) by optimizing the design of a three-channel serpentine flow field. The focus is on the introduction of sub-channels beneath the flow field ribs, utilizing the pressure differential between the main and sub-channels to strengthen lateral convection under the ribs, thus achieving uniform distribution of reaction gases. Using Computational Fluid Dynamics (CFD) methods, the performance of traditional and optimized flow fields were compared across various metrics. The results show that the introduction of sub-channels significantly improves gas mass transfer efficiency, enhances the uniformity of oxygen concentration and current density, and optimizes water content on the proton exchange membrane. At a voltage of 0.5 V, the Improved Serpentine Flow Field (ISCF) exhibits a notable enhancement in current density, increasing from 1.501 A/cm2 in the Traditional Serpentine Flow Field (TCSF) to 1.654 A/cm2 in the ISCF. This represents a significant 10 % increase in current density. Concurrently, the uniformity index climbs from 0.84 to 0.898, marking a 7 % improvement in uniformity. Furthermore, the ISCF design achieves a substantial reduction in pressure drop, decreasing from 1631 Pa to 1212 Pa, a reduction of 26 %. Additionally, the expansion of sub-channel width markedly boosts cell performance, whereas the Increase in sub-channel height reaches a saturation point beyond a certain threshold, indicating an optimal range for dimensional adjustments.

Active optimization adjustment for the surface accuracy of spaceborne SAR antennas

Inevitable disturbances in the spatial thermal environment will seriously degrade the surface accuracy of satellite antennas. Unfortunately, the ground pre-adjustment cannot adaptively guarantee the antenna performance under alternating thermal loadings. To tackle the challenge, this study proposes an active optimization adjustment method to achieve the required surface accuracy for spaceborne antennas. Starting from the comprehensive analysis of external thermal fluxes in outer space, the heat transfer model is firstly established to acquire the temperature field of the antenna system. Subsequently, considering the thermoelastic effect and the geometrical nonlinearity, the antenna surface accuracy is predicted. In particular, the thermoelastic forces induced from temperature changes and dimensional deviations are precisely determined by the absolute nodal coordinate formulation. Moreover, an efficient computational method with invariant matrices is developed to accelerate the prediction. On this basis, we construct the on-orbit active adjustment model to compensate for the effect of thermally induced deformation on the surface accuracy. A mixed-variable optimization algorithm is further put forward to find the optimal strategy of dimensional adjustment. Finally, a case study with simulation analysis and experiment verification demonstrates the feasibility and superiority of the proposed surface adjustment method.

DEVICES FOR DIMENSIONAL ADJUSTMENT OF THE CUTTING OF LATHE MACHINES

In this paper, the factors affecting the processing accuracy of lathes are examined. The paper highlights their environments, the dominant factors that have the greatest influence on the processing accuracy. The possibilities of increasing the processing accuracy on existing lathes by eliminating the influence of dominant factors on the processing accuracy is analyzed. The authors describes the place and value of the dimensional adjustment of the cutting edge of lathes while ensuring the accuracy of processing of parts such as a body of revolution, a method and a schematic diagram of a device for precision adjustment of the cutters of a lathe to the size to be machined are proposed in this paper.

The construction of a two-dimensional organic-inorganic hybrid double perovskite ferroelastic with a high T c and narrow band gap.

Two-dimensional (2D) hybrid double perovskites have attracted extensive research interest for their fascinating physical properties, such as ferroelectricity, X-ray detection, light response and so on. In addition, ferroelastics, as an important branch of ferroic materials, exhibits wide prospects in mechanical switches, shape memory and templating electronic nanostructures. Here, we designed a 2D phase-transition double perovskite ferroelastic through a structurally progressive strategy. This evolution is core to our construction process from 0D to 1D and AgBi-based 2D. In this way, we successfully synthesized 2D lead-free ferroelastic (DPA)4AgBiBr8 (DPA = 2,2-dimethylpropan-1-aminium) with a high Curie temperature (Tc), which shows a narrower band gap than 0D (DPA)4Bi2Br10 and 1D (DPA)5Pb2Br9. Moreover, the mechanism of structural phase transition and molecular motion are fully characterized by temperature dependent solid-state NMR and single crystal XRD. (DPA)4AgBiBr8 injects power into the discovery of new ferroelastics or the construction and dimensional adjustment in new hybrid double perovskites.

Desain Dan Implementasi Data Warehouse Pada Perpustakaan Daerah Provinsi Sumatera Selatan

This research will focus on processing visitor data, member data, book borrowing data and book return data at the Regional Library of South Sumatra Province. The data is stored in the form of an excel file with a large amount of data, causing problems in the storage system such as data accumulation, data loss, no data analysis and delays in the reporting process. The process of data storage and data retrieval will be well integrated by building a data Warehouse at the Regional Library of South Sumatra Province. Data Warehouse is a system that contains several years of history and facilitates decision making. At the data Warehouse design stage using the Nine-Step method (Kimball, 2002), in this method there are nine steps in designing a data Warehouse, namely Process Selection, Grain Selection, Identification of dimensional adjustments, Fact Selection, Storage of initial calculations in the fact table, Reviewing the dimension table, selecting the database duration, tracking dimension changes, and prioritizing, querying the model and selecting the physical design. And the design and data processing process will use the Pentaho kettle and public Tableau applications, with the design and implementation of the data Warehouse, it is expected to help facilitate the reporting and analysis process for the Regional Library of South Sumatra Province.

Facile Surfactant‐, Reductant‐, and Ag Salt‐free Growth of Ag Nanoparticles with Controllable Size from 35 to 660 nm on Bulk Ag Materials

Morphologically and dimensionally controlled growth of Ag nanocrystals has long been plagued by surfactants or capping agents that complicate downstream applications, unstable Ag salts that impaired the reproducibility, and multistep seed injection that is troublesome and time-consuming. Here, we report a one-pot electro-chemical method to fast (∼2 min) produce Ag nanoparticles from commercial bulk Ag materials in a nitric acid solution, eliminating any need for surfactants or capping agents. Their size can be easily manipulated in an unprecedentedly wide range from 35 to 660 nm. Furthermore, the Ag nanoparticles are directly grown on the Ag substrate, highly desirable for promising applications such as catalysis and plasmonics. The mechanistic studies reveal that the concentration of Ag+ in the diffusion layer nearby the surface, controlled by the magnitude and duration of voltage, is critical in governing the nanoparticle formation (<1.3 mM) and its dimensional adjustability.

Link Adjustment for Assembly Deviation Control of Extendible Support Structures via Sparse Optimization

The assembly accuracy of the extendible support structure is of importance for the imaging capability of synthetic aperture radar antennas. In general, due to manufacturing imperfections and installation variations, its assembly accuracy will be inevitably degraded. Therefore, controlling the assembly deviation is highly concerned in practice. To meet the accuracy requirement and make “the control” more efficient, this study proposes a novel method to quantitatively conduct dimensional adjustment of links for extendible support structures of synthetic aperture radar antennas. Since the extendible support structure is generally over-constrained in the deployed configuration, the relationship between the assembly deviation and the variation sources is first derived by means of equivalent transformation. Based on the mathematical expression of assembly deviation, an inequality constrained sparse optimization model for quantitatively resizing links is formulated. Then, an efficient algorithm integrating the alternating direction method of multipliers and binary search is developed to solve the above optimization model, thereby acquiring the optimal combination of link adjustment. Finally, numerical case studies are carried out to demonstrate the effectiveness of the proposed method in Matlab, which show that it can not only achieve satisfactory performance in prediction but also significantly improve the assembly efficiency.

Does Positive Wellbeing Predict Job Performance Three Months Later?

The present study examines the relationship between wellbeing and work performance in a twotime model. The model was based on the happy-productive worker hypothesis. Labour wellbeing (Time 1, T1) was measured with three constructs: job satisfaction, personal satisfaction, and organizational commitment, and showed good one dimensional adjustment in the second-order confirmatory factor analysis performed. We use a stratified sampling strategy, controlling for sex, age and whether workers were employed in the public or private sector. Of the 235 employees analysed in T1, 205 responded in Time 2 (T2). Results obtained through SEM analysis establish a positive and significant relationship between positive wellbeing and job performance. Likewise, job satisfaction and organizational commitment were the variable that most influenced the unidimensional welfare construct (0.902, p < 0.001 and 0.750, p < 0.001, respectively). Personal satisfaction showed a lower value (0.234, p < 0.01), and was the only one of the three variables that was context-free level. The article looks at the theoretical and professional implications of the results.

Necessary gradient restrictions at the core of a voting rule

This paper generalizes known gradient restrictions for the core of a voting rule parameterized by an arbitrary quota. For the special case of majority rule with an even number of voters, the result implies that given any pointed, finitely generated, convex cone C, the difference between the number of voters with gradients in C and the number with gradients in −C cannot exceed the number of voters with zero gradient, plus a dimensional adjustment. When the cone has dimensionality less than three, the adjustment is zero. A difficulty in the proof of a result of Schofield (1983), which neglects the dimensional adjustment term, is identified, and a counterexample (in three dimensions) presented.

Planning Method of B6 in Kaunos Design Methods of a Rock-Cut Tomb in Southeast of Karia

The aim of this study is to identify the planning method of B6 in Kaunos. Assuming proportional relationships of each part were applied in the construction, as in the ancient Greek temples and stoas, the planning of B6 was investigated, leading to a conclusion that rough calculation of the scale has been determined first as a scheme design, followed by dimensional adjustment of each part in the execution stage. Further, the study identified that the planning is based on a grid technique using 3 feet as a grid, with proportional design and dimensional adjustments employed in the facade

Development of the Korean culture adjustment scale for Chinese workers in Korea and exploration into the different internal structure of Korean Chinese and Han Chinese

This study was conducted to develop a scale which can measure the Korean culture adjustment of Chinese workers employed in Korea. In the study 1, we selected 4 sub-dimensions and 24 questions that measure the characteristics of Korean culture adjustment through literature review and in-depth interviews. In the study 2, we conducted surveys on 405 Chinese workers to verify the constructs of the Korean culture adjustment scale. Subjects were divided into the two groups of Korean Chinese and Han Chinese, exploratory analysis was conducted in Exploratory Structure Equation Model frame. If sub-divisions are observed by group, the Korean Chinese group showed a 3 dimensional (adjustment to occupational environments, adjustment to living environments, psychological adjustment) structure and the Han Chinese showed a 4 dimensional (adjustment to occupational environments, adjustment to living environments, psychological adjustment, communicational adjustment) structure. In particular, communicational adjustment was a factor drawn only from the Han Chinese through factor analysis. This implied that the reason is because the language used by the Korean Chinese is similar to the Korean language. In the study 3, multi-group analysis was performed to observe whether a measurement model of the Korean culture adjustment scale can generalize or differentiate between groups. As a result, equal interpretation between groups was possible for questions forming coidentity. The Korean culture adjustment scale developed in this study is significant in that it can assess the unique Korean culture adjustment of Chinese workers.

Development of the Korean Culture Adjustment Scale for Chinese Workers in Korea and Exploration into the Different Internal Structure of Korean Chinese and Han Chinese: A Preliminary Study

This study was conducted to develop a scale which can measure the Korean culture adjustment of Chinese workers employed in Korea. In the study 1, we selected 4 sub-dimensions and 24 questions that measure the characteristics of Korean culture adjustment through literature review and in-depth interviews. In the study 2, we conducted surveys on 405 Chinese workers to verify the constructs of the Korean culture adjustment scale. Subjects were divided into the two groups of Korean Chinese and Han Chinese, exploratory analysis was conducted in Exploratory Structure Equation Model frame. If sub-divisions are observed by group, the Korean Chinese group showed a 3 dimensional (adjustment to occupational environments, adjustment to living environments, psychological adjustment) structure and the Han Chinese showed a 4 dimensional (adjustment to occupational environments, adjustment to living environments, psychological adjustment, communicational adjustment) structure. In particular, communicational adjustment was a factor drawn only from the Han Chinese through factor analysis. This implied that the reason is because the language used by the Korean Chinese is similar to the Korean language. In the study 3, multi-group analysis was performed to observe whether a measurement model of the Korean culture adjustment scale can generalize or differentiate between groups. As a result, equal interpretation between groups was possible for questions forming coidentity. The Korean culture adjustment scale developed in this study is significant in that it can assess the unique Korean culture adjustment of Chinese workers.

Elaboração e caracterização de compósitos magnéticos

No processo de têmpera por indução, o material é aquecido por um campo magnético gerado por uma corrente alternada de alta frequência, que passa através de uma bobina. Para melhorar a eficiência do processo, são utilizados, junto à bobina, orientadores de fluxo magnético, que são materiais magnéticos moles. Esses orientadores de fluxo são constituídos de componentes ferromagnéticos e um ligante dielétrico. Geralmente é necessário realizar um ajuste dimensional desses concentradores, através de usinagem, gerando perda de matéria-prima e produção de resíduo. Nesse trabalho, foi realizada a elaboração de um compósito de matriz polimérica a partir do resíduo oriundo do processo de ajuste dimensional. Para elaboração desse compósito, o resíduo foi cominuído e misturado com dois tipos diferentes de resinas fenólicas na concentração de 3%. Os compósitos magnéticos obtidos foram caracterizados quanto à morfologia, propriedades mecânicas, magnéticas, elétricas e caracterização ambiental. Os resultados mostraram que os compósitos apresentaram redução das propriedades magnéticas e mecânicas comparativamente ao material original. Mesmo assim o material apresenta potencial para uso como concentrador de fluxo, pois foi observada a redução das perdas magnéticas.

Thermal Analysis on the Shell Stiffeners of Double Steel Wall LNG Storage Tank

Shell stiffeners are used effectively to prevent preferential local buckling of LNG tank shell. In this paper, Finite element method (FEM) is applied to pay attention to the thermal analysis on the shell stiffeners of double steel wall LNG storage tank. The structural requirements according to British Standard 7777-2:1993 has been considered and then some dimensional adjustments of shell stiffeners are made to evaluate their influence on the thermal field of double steel wall LNG storage tank. Temperature distributions and heat flux of different dimensional shell stiffeners are presented. Though the analysis of results, it puts forward the conclusion that the dimensional design of shell stiffeners used in double steel wall LNG storage tank shall take not only the structural design requirements but also the thermal design ones into consideration in order to finally save cost in both construction and normal operation.

Useful measures in the field of time and dimensional rationalisation of manual training lessons

Schoolwork, especially lessons in manual skills is often associated with various ergonomics stresses. These stresses are the result not only of school obligations but also of the physical working environment and inadequate lesson planning. Much can be done in this field if certain approaches are taken into consideration at the work planning stage. Thus we can use certain analytical methods, such as the Method of Temporary Observations (Multi-Moment Method) and OWAS (a method for the evaluation of postural load during work), when positioning stressful lesson factors. This can be done in a relatively simple way in the field of time rationalisation as well as in the field of dimensional work adjustment to pupils. Research results in this paper show that by using a planned directed approach in this field, it is possible to achieve, a higher level of efficiency with normal levels of fatigue.

The Evolution of Private and Open Access Property

In this Article we explore the evolution of property law and examine the applicability of the prevailing accounts according to which property institutions oscillate between the extreme points of open access and private property. We show that the evolution of property is a much more nuanced process, shaped by the interplay of the following three dimensions: number of owners, extent of dominion and asset configuration. Accordingly, property institutions can assume a myriad of positions along the aforementioned dimensions in response to the constant change in exclusion and management costs. We demonstrate our theory by discussing examples of three dimensional adjustments of real, personal and intellectual property.

Assembly synthesis with subassembly partitioning for optimal in-process dimensional adjustability

Achieving the dimensional integrity for a complex structural assembly is a demanding task due to the manufacturing variations of parts and the tolerance relationship between them. Although assigning tight tolerances to all parts would solve the problem, an economical solution is taking advantage of small motions that joints allow, such that critical dimensions are adjusted during assembly processes. This paper presents a systematic method that decomposes product geometry at an early stage of design, selects joint types, and generates subassembly partitioning to achieve the adjustment of the critical dimensions during assembly processes. A genetic algorithm generates candidate assemblies based on a joint library specific for an application domain. Each candidate assembly is evaluated by an internal optimization routine that computes the subassembly partitioning for optimal in-process adjustability, by finding a series of minimum cuts on weighted graphs. A case study on a three-dimensional automotive space frame with the accompanying joint library is presented.

A systematic method of adaptive joint design considering different assembly sequence in sheet metal product

In sheet metal assembly, not only the component variations and tool errors, but also the component structure (joint type) and assembly process (assembly sequence) affect the final dimensional quality. In this paper, a systematic method for adaptive joint design considering different assembly sequence is proposed to meet the in-process dimensional adjustability of KCs (key characteristics). First, the adaptive characteristic of the sheet metal joint is depicted. Then, the mathematical model in order for concurrently optimizing both joint type and different assembly sequence is presented. How to evaluate the combination of joint type and assembly sequence is carried out according to two conditions: (1) for single KC, and (2) for multiple KCs. The KC confliction is considered to ensure the important KCs. Genetic algorithm is used to resolve the optimization of joint design. An example is chosen to demonstrate our method finally, and various joint designs are acquired according to different assembly sequences by this means. The proposed methods make it possible for us to improve the dimensional quality of product in the design stage.

Selection and Optimization of Piezoelectric Polyvinylidene Fluoride Polymers for Adaptive Optics in Space Environments

Various piezoelectric polymers based on polyvinylidene fluoride (PVDF) are of interest for large aperture space-based telescopes. Dimensional adjustments of adaptive polymer films depend on charge deposition and require a detailed understanding of the piezoelectric material responses which are expected to deteriorate owing to strong vacuum UV, γ -, X-ray, energetic particles and atomic oxygen exposure. We have investigated the degradation of PVDF and its copolymers under various stress environments detrimental to reliable operation in space. Initial radiation aging studies have shown complex material changes with lowered Curie temperatures, complex material changes with lowered melting points, morphological transformations and significant crosslinking, but little influence on piezoelectric d33 constants. Complex aging processes have also been observed in accelerated temperature environments inducing annealing phenomena and cyclic stresses. The results suggest that poling and chain orientation are negatively affected by radiation and temperature exposure. A framework for dealing with these complex material qualification issues and overall system survivability predictions in low earth orbit conditions has been established. It allows for improved material selection, feedback for manufacturing and processing, material optimization/stabilization strategies and provides guidance on any alternative materials.