design parameter
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Author(s):  
Daniel A. Porter ◽  
Matthew A. Di Prima ◽  
Yutika Badhe ◽  
Ankit R. Parikh

Author(s):  
T Van Zwijnsvoorde ◽  
M Vantorre

Container traffic and individual ships’ sizes increased dramatically over the last decades, testing the existing harbour infrastructure to its limits. An important aspect regarding the safety of the berthed vessel is the quality of the mooring configuration. A case study is presented, where an 18000 TEU container vessel is moored at a quay. The motions of the moored vessel and the forces in its lines due to ship passages are simulated, using the potential software ROPES and the UGent in-house package Vlugmoor. Focus is on the mooring plan (operational parameter) and the characteristics of the individual lines (design parameter).


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Seyhun Durmus

Purpose Blended wing body (BWB) is a very advantageous design in terms of low fuel consumption, low emission and low noise levels. Because of these advantages, the BWB is a candidate to become the commercial passenger aircraft of the future by providing a paradigm shift in conventional designs. This paper aims to propose a key design parameter for wing sizing of subsonic BWB and a performance parameter for calculating the lift/drag ratio values of BWBs. Design/methodology/approach The parameter proposed in the study is based on the square/cube law, that is, the idea that the wetted area is proportional to the power of 2/3 of the weight. Data on the weight, wing area, wingspan, lift-to-drag (L/D) ratio for 19 BWB used in the analyzes were compiled from the published literature and a theoretical methodology was developed to estimate the maximum lift to drag ratio of BWBs. The accuracy of the proposed key design parameter was questioned by comparing the estimated L/Dmax values with the actual values. Findings In the current study, it is claimed that the wingspan/(take-off gross weight)(1/3) parameter provides an L/D efficiency coefficient regardless of aircraft size. The proposed key design parameter is useful both for small-scale BWB, that is unmanned aerial vehicles BWB and for large-scale BWB designs. Therefore, the b/Wg(1/3) parameter offers a dimensionless L/D efficiency coefficient for BWB designs of different scales. The wetted aspect ratio explains how low aspect ratio (AR)-BWB designs can compete with high AR-tube-and-wing designs. The key parameter is also useful for getting an idea of good or bad BWB with design and performance data published in the literature. As a result, reducing the blending area and designing a smaller central body are typical features of aerodynamically efficient BWB. Originality/value As the role of the square/cube law in the conceptual aircraft design stage has not been sufficiently studied in the literature, the application of this law to BWBs, a new generation of designs, makes the study original. Estimation of the wetted area ratio using only wingspan and gross weight data is an alternative and practical method for assessing the aerodynamic performance of the BWB. According to the model proposed in the current study, reducing the take-off gross weight of the BWBs using lighter building materials and designing with a larger wingspan (b) are the main recommendations for an aerodynamically efficient BWB.


Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2113
Author(s):  
Yuqi Li ◽  
Dayong Yang ◽  
Chuanmei Wen

In this paper, the Nonlinear Auto-Regressive with exogenous inputs (NARX) model with parameters of interest for design (NARX-M-for-D), where the design parameter of the system is connected to the coefficients of the NARX model by a predefined polynomial function is studied. For the NARX-M-for-D of nonlinear systems, in practice, to predict the output by design parameter values are often difficult due to the uncertain relationship between the design parameter and the coefficients of the NARX model. To solve this issue and conduct the analysis and design, an improved algorithm, defined as the Weighted Extended Forward Orthogonal Regression (WEFOR), is proposed. Firstly, the initial NARX-M-for-D is obtained through the traditional Extended Forward Orthogonal Regression (EFOR) algorithm. Then a weight matrix is introduced to modify the polynomial functions with respect to the design parameter, and then an improved model, which is referred to as the final NARX-M-for-D is established. The genetic algorithm (GA) is used for deriving the weight matrix by minimizing the normalized mean square error (NMSE) over the data sets corresponding to the design parameter values used for modeling and first prediction. Finally, both the numerical and experimental studies are conducted to demonstrate the application of the WEFOR algorithm. The results indicate that the final NARX-M-for-D can accurately predict the system output of a nonlinear system. The new algorithm is expected to provide a reliable model for dynamic analysis and design of the nonlinear system.


Author(s):  
Sina Kheiri ◽  
Eugenia Kumacheva ◽  
Edmond W.K. Young

Microfluidic tumour spheroid-on-a-chip platforms enable control of spheroid size and their microenvironment and offer the capability of high-throughput drug screening, but drug supply to spheroids is a complex process that depends on a combination of mechanical, biochemical, and biophysical factors. To account for these coupled effects, many microfluidic device designs and operating conditions must be considered and optimized in a time- and labour-intensive trial-and-error process. Computational modelling facilitates a systematic exploration of a large design parameter space via in silico simulations, but the majority of in silico models apply only a small set of conditions or parametric levels. Novel approaches to computational modelling are needed to explore large parameter spaces and accelerate the optimization of spheroid-on-a-chip and other organ-on-a-chip designs. Here, we report an efficient computational approach for simulating fluid flow and transport of drugs in a high-throughput arrayed cancer spheroid-on-a-chip platform. Our strategy combines four key factors: i) governing physical equations; ii) parametric sweeping; iii) parallel computing; and iv) extensive dataset analysis, thereby enabling a complete “full-factorial” exploration of the design parameter space in combinatorial fashion. The simulations were conducted in a time-efficient manner without requiring massive computational time. As a case study, we simulated >15,000 microfluidic device designs and flow conditions for a representative multicellular spheroids-on-a-chip arrayed device, thus acquiring a single dataset consisting of ∼10 billion datapoints in ∼95 GBs. To validate our computational model, we performed physical experiments in a representative spheroid-on-a-chip device that showed excellent agreement between experimental and simulated data. This study offers a computational strategy to accelerate the optimization of microfluidic device designs and provide insight on the flow and drug transport in spheroid-on-a-chip and other biomicrofluidic platforms.


2021 ◽  
pp. 1-21
Author(s):  
Wassim Habchi

Abstract This work presents a comprehensive numerical study of thermal elastohydrodynamic lubrication performance in axially crowned rollers, based on a full-system finite element approach. Axial crowning has always been introduced to finite line contacts, as a mean for improving film thickness. Its influence on friction has often been overlooked though. The current work reveals that axial crowning has a negative influence on friction, increasing it significantly with respect to the reference case of straight rollers. It is shown that, with increased crowning height (or reduced crowning radius), minimum film thickness is increased, but so is friction. Therefore, film thickness enhancement comes at the expense of a deterioration in friction. Besides, achieving sufficient enhancements in minimum film thickness would require using relatively low crowning radii, which would lead to a substantial increase in friction. The frictional increase is traced back to an overall increase in contact pressures and effective contact area within the lubricating conjunction. It is also shown that, when film thickness is the most critical design parameter, the best compromise between enhanced film thickness and deteriorated friction would be to combine axial crowning with roller-end profiling. However, when friction is the most critical design parameter, a simple roller-end profiling would offer the best compromise.


2021 ◽  
Author(s):  
Miaomiao Zhang

<div>In this paper, a varying-gain zeroing (or Zhang) neural network (VG-ZNN) is proposed to obtain the online solution of the time-varying linear equation and inequality system. Distinguished from the fixed-value design parameter in</div><div>the original zeroing (or Zhang) neural network (ZNN) models, the design parameter of the VG-ZNN model is a nonlinear function that changes with time. The VG-ZNN model composed of the new time-varying design parameter we proposed can achieve fixed-time convergence and tolerate time-varying bounded noise and time-varying derivable noise. The theoretical detailed analysis of the convergence and robustness of the VG-ZNN model are given.</div>


2021 ◽  
Author(s):  
ziyu liao ◽  
baichen

Abstract The supernumerary robotic limbs(SRLs) is a new type of wearable robot that assists the operator with additional robotic limbs and allows the operator to perform multiple tasks simultaneously. Due to the SRLs having various combinations of robotic limb and attachment positions, and there is an insufficient discussion on the influence of different wear positions on the SRLs. Therefore, this paper improved the evaluation indexes from previous studies and presents an experimental evaluation of the performance of indexes between humans and SRLs. This paper analyzed the 5 different positions based on the improved evaluation indexes, 2 optimal positions are found with the simulation experiment. Then the two design factors to improve the performance of evaluation indexes are discussed. The evaluation indexes can be utilized as a design parameter for evaluating human-robot interactions of SRLs.


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