scholarly journals Multi-Objective Parameter Optimization of Flexible Support System of Optical Mirror

2021 ◽  
Vol 11 (17) ◽  
pp. 8071
Author(s):  
Zujin Jin ◽  
Gang Cheng ◽  
Yusong Pang ◽  
Shichang Xu ◽  
Dunpeng Yuan

During the processing of an optical mirror, the performance parameters of the bottom support system would affect the surface forming accuracy of the mirror. The traditional bottom support system has a large unadjustable support stiffness, which increases the difficulty of unloading the impact force generated by the grinding disc. In response to this scenario, a flexible support system (FSS) consisting of 36 support cylinders with beryllium bronze reeds (BBRs) and rolling diaphragms (RDs) as key components is designed. It is necessary to analyze the key components of the support cylinder to reduce its axial movement resistance, ensure a consistent force output of each support point. First, the internal resistance model of a flexible support cylinder is established, and the main factors of internal resistance are then analyzed. Thereafter, the multi-objective structural parameters of the BBR and RD are simulated in ANSYS using the control variable method. The optimal structural parameters of BBR and RD are determined by simulation. Finally, experiments are performed on the RD ultimate pressure, internal resistance of the support cylinder, and consistency of the force output of the FSS. The experimental results show that the support cylinder with the optimized design has good force output consistency, which provides a theoretical basis for the application of FSS in optical mirror processing.

2017 ◽  
Vol 21 (2) ◽  
pp. 111-133 ◽  
Author(s):  
Arunangshu Mukhopadhyay ◽  
Vinay Kumar Midha ◽  
Nemai Chandra Ray

Purpose This study aims to optimize the parametric combination of injected slub yarn to achieve least abrasive damage on fabrics produced from it. Design/methodology/approach Single base injected slub yarn structural parameters, vis-à-vis slub length, slub thickness and slub frequency, were varied during preparation of yarn samples under this research work. A total of 17 yarn samples were produced according to the Box and Bhenken design of the experiment. Subsequently knitted and woven (using injected slub yarns in the weft only) fabric samples were prepared from these yarns. Yarn and fabric samples were abraded with standard instruments to see the impact of yarn structural parameters on abrasive damage of fabric in terms of fabric mass loss and appearance deterioration. From the test results, empirical models relating to slub parameters and fabric abrasion behavior were developed through a backward elimination regression approach. Subsequently, a set of optimal parametric combinations was derived with multi-objective evolutionary algorithms by using MATLAB software. This was followed by ranking all optimal solutions through technique for order preference by similarity to idle solution (TOPSIS) score analysis. Findings The injected slub yarn’s structural parameters have a strong influence on the abrasive damage of knitted and woven fabric. It is seen that the best suitable parametric combination of slub parameters for achieving the least abrasive damage is not the same for knitted and woven fabric. Practical implications The spinner can explore this concept to find out the best suitable parametric combination during pattern making of injected slub yarn through MATLAB solution followed by TOPSIS score analysis based on their priority of criteria level to ensure better abrasion behavior of fabric produced. Originality/value Optimization of parametric combination of injected slub yarns will help to ensure production of fabric with most resistance to abrasion for specific applications. The studies showed that the optimal solution for woven and knitted fabrics is different. The result indicates that in the case of knitted fabric, comparatively lesser slub thickness is found to be suitable for getting better fabric abrasion resistance, whereas in the case of woven fabric, comparatively higher slub thickness is found suitable for the same.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Weigang Deng ◽  
Chunguang Wang ◽  
Shengshi Xie

Abstract To obtain the collision characteristics of potatoes colliding with steel rods of different parameters, the finite element analysis (FEA) method was used to study the impact contact stress, collision displacement, acceleration and impact force. The results showed that with increasing rod diameter, the maximum collision displacement of the potato in the Y direction decreased, and the maximum collision acceleration and impact peak force increased. With increasing rod tilt angle and rod spacing, the maximum collision displacement increased linearly, but the maximum collision acceleration and impact peak force decreased linearly. Within the range of analysis factors, the fluctuation of the maximum collision displacement, acceleration and impact peak force caused by the change in rod diameters were the smallest, which were 0.34 mm, 38 m/s2 and 9 N, respectively. When potatoes collided with single and double rods, all the collision characteristics increased with the increase in potato drop height, and the results for double rods were significantly smaller than those for single rod collision. When the potato mass was 250 g, the drop height was 200 mm for single rod collision or 250 mm for double rod collision, the impact contact stress reached the yield stress, and the potato was damaged. This article provides a data basis and a referenced method for the optimized design of the structural parameters and working parameters of the rod separator in the process of potato mechanized harvesting.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 47-54 ◽  
Author(s):  
D. S. Yakowitz ◽  
J. J. Stone ◽  
L. J. Lane ◽  
P. Heilman ◽  
J. Masterson ◽  
...  

A prototype Multi-Objective Decision Support System (MODSS) for water quality has been developed by the Agricultural Research Service at the Southwest Watershed Research Center in Tucson, Arizona. The Decision Support System uses a simulation model to predict the impact of alternative management systems on surface and groundwater quality as well as farm income. The results of the simulation, which includes modeling of hydrology, erosion, nutrient and pesticide transport, crop growth and economics, are analyzed with respect to the multiple objectives of reducing surface and groundwater pollution while maintaining or improving farm income. Often these objectives are in conflict and objectively discerning which practice is preferred can be a difficult task. The multi-objective decision making component of the decision support system makes use of dimensionless utility functions and the concept of importance order dominance. The MODSS allows the user to set up alternatives, choose the decision criteria, and accept or customize the decision mode settings. The results are presented graphically as well as in tabular form. The dominance of one practice over another, if it exists, is clearly evident in the graphical presentation. We illustrate the decision component of the MODSS with pictures of the screens from an example which uses the simulation results of several management alternatives on farmland in the Deep Loess Soil Major Land Resource Area near Treynor, Iowa.


GIS Business ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 47-52
Author(s):  
Karam Pal Narwal ◽  
Sonia Jindal

The paper empirically examines the impact of corporate governance on the cash holding of the firms. The components of corporate governance are measured by board size, board meeting, audit committee members, directors remuneration and non executive directors and the cash holding is measured with the log of average cash and size is taken as control variable for the control effect on the dependent variables. Moreover, correlation and panel regression model were employed to examine the relationship between the corporate governance and cash holding. Empirical data was collected from 96 firms over the period of 2004-05 to 2013-14. The results show that directors remuneration and the number of audit committee members positively influence the cash holding and the board size also positively influences the cash holding whereas, the non executive directors and the board meetings do not play any role in enhancing the cash holding.


Author(s):  
Yu Guangbin ◽  
◽  
Duan Yuanwang ◽  
Zhao Xinhui ◽  
Tian Ren ◽  
...  

2009 ◽  
Vol 55 (No. 11) ◽  
pp. 541-549 ◽  
Author(s):  
L. Čechura

The paper deals with the theoretical analysis of the impact of credit rationing on farmer’s economic equilibrium. The analysis is carried out based on the derived dynamic optimization model, which is the dynamic investment model with adjustment costs. The credit rationing is introduced by imposing an upper limit on the control variable, which is in this case represented by the investment spending. Then, the optimal control is used to solve the optimization problem in the situation of both with and without credit constraints. Finally, the situations without and with credit rationing are compared. The results show that the occurrence of credit rationing or in general financial constraints significantly determines the capital accumulation and investment decisions of farmers and as a result their supply functions.


Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.


Author(s):  
Suzanne L. van Winkel ◽  
Alejandro Rodríguez-Ruiz ◽  
Linda Appelman ◽  
Albert Gubern-Mérida ◽  
Nico Karssemeijer ◽  
...  

Abstract Objectives Digital breast tomosynthesis (DBT) increases sensitivity of mammography and is increasingly implemented in breast cancer screening. However, the large volume of images increases the risk of reading errors and reading time. This study aims to investigate whether the accuracy of breast radiologists reading wide-angle DBT increases with the aid of an artificial intelligence (AI) support system. Also, the impact on reading time was assessed and the stand-alone performance of the AI system in the detection of malignancies was compared to the average radiologist. Methods A multi-reader multi-case study was performed with 240 bilateral DBT exams (71 breasts with cancer lesions, 70 breasts with benign findings, 339 normal breasts). Exams were interpreted by 18 radiologists, with and without AI support, providing cancer suspicion scores per breast. Using AI support, radiologists were shown examination-based and region-based cancer likelihood scores. Area under the receiver operating characteristic curve (AUC) and reading time per exam were compared between reading conditions using mixed-models analysis of variance. Results On average, the AUC was higher using AI support (0.863 vs 0.833; p = 0.0025). Using AI support, reading time per DBT exam was reduced (p < 0.001) from 41 (95% CI = 39–42 s) to 36 s (95% CI = 35– 37 s). The AUC of the stand-alone AI system was non-inferior to the AUC of the average radiologist (+0.007, p = 0.8115). Conclusions Radiologists improved their cancer detection and reduced reading time when evaluating DBT examinations using an AI reading support system. Key Points • Radiologists improved their cancer detection accuracy in digital breast tomosynthesis (DBT) when using an AI system for support, while simultaneously reducing reading time. • The stand-alone breast cancer detection performance of an AI system is non-inferior to the average performance of radiologists for reading digital breast tomosynthesis exams. • The use of an AI support system could make advanced and more reliable imaging techniques more accessible and could allow for more cost-effective breast screening programs with DBT.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1230
Author(s):  
Jessica Manzi ◽  
Annalisa Paolone ◽  
Oriele Palumbo ◽  
Domenico Corona ◽  
Arianna Massaro ◽  
...  

In this manuscript, we report a detailed physico-chemical comparison between the α- and β-polymorphs of the NaMnO2 compound, a promising material for application in positive electrodes for secondary aprotic sodium batteries. In particular, the structure and vibrational properties, as well as electrochemical performance in sodium batteries, are compared to highlight differences and similarities. We exploit both laboratory techniques (Raman spectroscopy, electrochemical methods) and synchrotron radiation experiments (Fast-Fourier Transform Infrared spectroscopy, and X-ray diffraction). Notably the vibrational spectra of these phases are here reported for the first time in the literature as well as the detailed structural analysis from diffraction data. DFT+U calculations predict both phases to have similar electronic features, with structural parameters consistent with the experimental counterparts. The experimental evidence of antisite defects in the beta-phase between sodium and manganese ions is noticeable. Both polymorphs have been also tested in aprotic batteries by comparing the impact of different liquid electrolytes on the ability to de-intercalated/intercalate sodium ions. Overall, the monoclinic α-NaMnO2 shows larger reversible capacity exceeding 175 mAhg−1 at 10 mAg−1.


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