Display omitted
•Millimeter-sized amplified piezoelectric actuators with high performance.•Enabled by millimeter-sized composite structure.•Incorporates carbon fiber flexure elements.•Scaling ...analysis facilitates rapid design and proper sizing of critical dimensions.
A millimeter-sized piezoelectric actuator with a flexible displacement-amplification frame incorporates design enhancements to achieve an increase in mechanical efficiency from 33 to 70% relative to existing designs. The basic insight enabling this improvement is a familiar one: to maximize the force transfer through a flexible transmission, the serial compliance of the transmission should be minimized. The execution is more complex, particularly due to the small size of the actuators, requiring careful material selection, design, and fabrication. We provide simple guidelines based on lumped parameter modeling and scaling analysis to assist designers in this challenging task and in customizing to specific size and output requirements. These actuators can be used as building blocks in millimeter-sized devices in which precise, linear motion is needed, and the method of analysis employed should be broadly useful to designers of similar devices looking to distill a complex mechanics problem down to a set of simple design guidelines.
Abstract
The performance of a double circular-arc tooth harmonic gear drive, which offers advantages over traditional designs, such as lower stress during contact and increased fatigue life, was ...investigated in this research. The gear drive’s meshing was simulated using dynamic analysis software RecurDyn, and a significant variation in output angular velocity was observed. To address this issue, experiments were planned using the Taguchi method with the L
9
(3
4
) orthogonal table. The data was analyzed using techniques such as average value calculation, signal-to-noise ratio calculation, variance analysis, and response chart analysis to identify the control factors with the greatest impact on output angular velocity variation. It was found that an improved design with lower output angular velocity variation could be obtained by adjusting these control factors to optimal levels. The findings suggest that the transmission quality of double circular-arc harmonic gear drives can be enhanced by combining multi-flexible body dynamic analysis with the Taguchi method.
Query processing over uncertain data has gained growing attention, because it is necessary to deal with uncertain data in many real-life applications. In this paper, we investigate skyline queries ...over uncertain data in distributed environments (DSUD query) whose research is only in an early stage. The state-of-the-art algorithm, called e-DSUD algorithm, is designed for processing this query. It has the desirable characteristics of progressiveness and minimum bandwidth consumption. However, it still needs to be perfected in three aspects. (1) Progressiveness. Each time it only returns one query result at most. (2) Efficiency. There are a significant amount of redundant I/O cost and numerous iterations which causes a long total query time. (3) Universality. It is restricted to the case where local skyline tuples are incomparability. To address these concerns, we first present a detailed analysis of the e-DSUD algorithm and then develop an improved framework for the DSUD query, namely IDSUD. Based on the new framework, we propose an adaptive algorithm, called ADSUD, for the DSUD query. In the algorithm, we redefine the approximate global skyline probability and choose local representative tuples due to minimum probabilistic bounding rectangle adaptively. Furthermore, we design a progressive pruning method and apply the reuse mechanism to improve its efficiency. The results of extensive experiments verify the better overall performance of our algorithm than the e-DSUD algorithm.
In low-dimensional data and within the framework of a classical linear regression model, we intend to compare variable selection methods and investigate the role of shrinkage of regression estimates ...in a simulation study. Our primary aim is to build descriptive models that capture the data structure parsimoniously, while our secondary aim is to derive a prediction model. Simulation studies are an important tool in statistical methodology research if they are well designed, executed, and reported. However, bias in favor of an “own” preferred method is prevalent in most simulation studies in which a new method is proposed and compared with existing methods. To overcome such bias, neutral comparison studies, which disregard the superiority or inferiority of a particular method, have been proposed. In this paper, we designed a simulation study with key principles of neutral comparison studies in mind, though certain unintentional biases cannot be ruled out. To improve the design and reporting of a simulation study, we followed the recently proposed ADEMP structure, which entails defining the aims (A), data-generating mechanisms (D), estimand/target of analysis (E), methods (M), and performance measures (P). To ensure the reproducibility of results, we published the protocol before conducting the study. In addition, we presented earlier versions of the design to several experts whose feedback influenced certain aspects of the design. We will compare popular penalized regression methods (lasso, adaptive lasso, relaxed lasso, and nonnegative garrote) that combine variable selection and shrinkage with classical variable selection methods (best subset selection and backward elimination) with and without post-estimation shrinkage of parameter estimates.
•Frequency optimization problems are defined for graphene/fibre reinforced plates.•Design efficiency indices are introduced to measure the effectiveness of optimization.•Effectiveness of non-uniform ...thickness, graphene/fibre reinforcements/angles is shown.•The increase of frequency may reach 50% comparing to plates with zero graphene.•Contribution of fibre types and boundary conditions is highlighted.
Optimal design and analysis of three-phase graphene/fibre reinforced laminated nanocomposite plates with respect to maximizing the fundamental frequency is the subject of the present study. Optimal design solutions are given for four different sets of design parameters. First design problem determines the optimal graphene contents of individual layers, the second one both graphene and fibre contents, the third optimizes the graphene and fibre contents as well as the layer thicknesses of individual layers, and the fourth problem optimizes the graphene and fibre contents, layer thicknesses and fibre orientations. Purpose of this approach is to assess and compare different levels of optimization by means of a design efficiency index and as such to determine the effectiveness of different design parameters in maximizing the fundamental frequency. Optimization is implemented using a Sequential Quadratic Programming algorithm and the mechanical properties of graphene/fibre nanocomposite are determined via micromechanical relations. Vibration analysis is conducted by the finite element method using four-noded Mindlin plate elements. Results are obtained for simply supported (SSSS), clamped (CCCC) and simply supported-clamped boundary conditions for opposite edges (SCSC). It is observed that non-uniform distributions of graphene and fibre as well as fibre orientations are quite effective in improving the design efficiency.
Continuous flow synthesis techniques have in recent years conquered laboratory scale synthesis, yet within the field of precision polymer synthesis its use is still not fully established despite the ...large advantages that can be gained from switching from classical batch‐wise chemistry to flow chemistry, often already by using relatively simple chip‐based or cheap tubular micro‐ and mesoscaled reactors. Translating a polymerization from batch to continuous flow marks not only a mere change in reactor engineering, but also leads to numerous advantages in the polymerization with respect to kinetics of processes and especially product quality. In flow, polymerizations are not only speed up, they also provide materials with better dispersities and higher chain end fidelities when conditions are chosen accordingly. The underpinning effects causing these improvements are demonstrated and discussed. Further, also information on required laboratory equipment and recent developments in online reaction monitoring are highlighted to give newcomers to the field an idea about the potential of continuous flow polymerization.
The advantages of using microreactors for precision polymer synthesis are highlighted and compared to classical polymerization methodologies, demonstrating that continuous flow reactors do not only lead to improved kinetics of processes, but also to a higher quality of the residual polymers. The field of continuous flow polymerization is still at its start, but the potential is eminent and some future developments are discussed.
Topology optimization for the design of electromagnetic (EM) devices has recently garnered significant interest, thanks to advancements in additive manufacturing techniques that enable the ...fabrication of intricate geometries. This has opened up new possibilities for using integral equation (IE) methods to solve EM problems, particularly in the analysis of inductive power transfer (IPT) devices. In this context, we introduce a novel topology optimization tool called TopIE, which is built upon the IE method for EM problem solutions. TopIE adopts the logic of topology optimization of binary structures (TOBSs), a sensitivity-based approach that leverages binary design variables to clearly differentiate the material properties within the design domain. The tool is specifically used for optimizing IPT devices, and sample implementations of the method are made publicly available. By combining the power of topology optimization and IE methods, TopIE offers a promising avenue for enhancing the design and performance of EM devices.
Background Within the field of childhood neurodisability, the tendency in the study of needs has been to categorize them based on ability (motor, verbal, cognitive). However, current perspectives ...such as F-words, family-centered practices, or the principles of family empowerment, lead the researcher to ask: What are these needs according to the stage of development? Methods and analysis A descriptive qualitative study will be carried out. Several methods will be followed to ensure the reliability and validity of the results, and the Standards for Reporting Qualitative Research and the Consolidated criteria for reporting qualitative research checklists will also be used to guide the project. Data collection is sought from three main sources: Focus groups (detection of needs), a survey to collect sociodemographic and clinical data necessary to obtain an overview of the context of the participants, and a survey to find out the level of satisfaction with this initiative. Discussion The results expected to be obtained after this study will respond to the main needs of families with childhood neurodisability, based on age groups and covering the whole territory of the Spanish population. Thanks to these detected needs, it will be possible to design future lines of work to improve the design of family-centered practices and increase the empowerment of families. The intention is to detect needs by stage of development, which can be categorized within the F-words framework, showing families and professionals a clear picture of the needs of this population.
Abstract
The personalization of products and services has become an inevitable trend in the manufacturing and service industry, but it is very difficult to identify users' personalized requirements ...accurately. This paper solves this problem by constructing an identifying model for personalized requirement based on user profiling. Firstly, the framework of the proposed model and the process of identifying the user's personalized requirements with this model are introduced, and then an experimental scheme for obtaining users' profiling data is designed. On this basis, an experiment is performed by investigating users' requirements for the computer to obtain the data, and the data are used for the analysis based on the proposed model. The analysis result shows that the model can reveal the difference among heterogeneous users well, find out the implicit requirements of users, and identify the gap between existing products and users' personalized requirements, which provides support to the subsequent improvement of product design.
We present a holistic approach for the photovoltaic (PV) module frame improvement that considers mechanical, electrical, economic, and ecological aspects for different frame designs. In a ...comprehensive study, the approach is applied to exemplary PV module frame designs. The analyses performed in this study show a potential improvement path of the module frame design. This leads to an overall better module performance and helps finding the balance point between technical performance, cost, and environmental impact. Based on the results, the PV module frame design affects the aspects analyzed in this work differently. For the comparison, we defined reference frame design with 16 and 20 mm front and rear frame widths. The improvement is reached by unitizing the frame width for both sides to 18 mm and increasing its cavity width to 12 mm instead of 8.5 mm. Tuning the frame parameters in this way leads to the best balance point for frame designs in this study regarding all aspects. The mechanical finite element method (FEM) simulation results show that even a small change on the frame width has a significant influence on the stress within the solar cells. Compared with the reference frame, the optimized frame design shows 2.6% less deflection, which corresponds to around 0.7 mm. Cell‐to‐module (CTM) analysis shows that a bigger frame width lightly decreases the cover coupling power gain. Results show that increasing the front frame width from 16 to 20 mm reduces the module power by about 0.12 WP. Findings of the cost of ownership (COO) analysis suggest that the optimized frame can save around 30 g aluminum which reduces the total module cost by 0.1%. Life cycle assessment (LCA) results are directly correlated to the material mass of the corresponding design. Results show that using the optimized frame can save 0.8 kg CO2‐eq/kWP due to the saving in aluminum compared with the reference frame.
In this publication, we share a holistic approach to improve the PV module frame by applying different analyses. The impact of different frame designs on the PV module was studied regarding mechanical stability, output power, cost, and CO2 emissions.
PDF
