Initial Design Model Research Articles

Communities of practice as an effective ECB approach for nonevaluation specialists: A case study in an Australian state government department

AbstractAmong the various evaluation capacity building strategies, there is an important opportunity to enhance the evidence on the effectiveness of communities of practice (CoPs). We argue that evaluation CoPs have great potential to develop evaluative thinking among nonevaluation specialists and build the foundations of a sustainable organizational evaluation culture. This article presents a case study of an evaluation community of practice in an Australian state government agency, with evidence collected over 4 years against a comprehensive evaluation framework. It outlines in detail an empirically tested evaluation‐CoP good practice from the initial design and logic model to implementation and measurement against individual, group, and organizational outcomes.

A novel optimization framework integrating multiple initialization, automatic topologization and MINLP reduction to accelerate large-scale heat exchanger network synthesis

Ensuring the solution feasibility and achieving an acceptable solution time for the non-deterministic polynomial-time hard (NP-hard) problem of heat exchanger network (HEN) synthesis is still challenging. In this study, we developed a novel optimization framework for efficiently solving large-scale HEN synthesis problems to obtain near global optimal solutions, simultaneously addressing the solution's infeasibility and time. The optimization framework consists of a multiple initial HEN design model (M-INI model), a new distance-based auto structure transformer (A-STR transformer), and a reduced non-linear programming model (R-NLP model). The M-INI model generates various HEN designs based on pinch analysis by varying the minimum approach temperature and the modes of stream splitting and mixing. The A-STR transformer is first proposed to automatically convert various HEN designs into associated superstructure-based topologies as multiple initial starting points for accelerating the solution of the R-NLP model. A strategy for approximating the temperature difference calculation is further applied to reduce the computational loads. Four case studies were conducted using the proposed method to minimize the total annual cost (TAC). The solutions of general cases 1 and 2 are almost equal to the best results in the literature, while the solution time is reduced by 98.7 % and 99.8 %, respectively, which demonstrates the performance of the proposed method. Especially, the method was applied to two practical industrial HEN cases: a large-scale low-grade heat recovery system and a crude distillation unit. The results of large-scale case 3 show that the optimal solution near the global optimal solution only requires 251.7 s. Case 4 includes pre-splitting in scenario A and free splitting in scenario B. Compared to scenario A, the TAC and solution time in scenario B were reduced by 33.9 % and 93.1 %, indicating that the pre-splitting strategy excludes the optimal from the search space. The proposed novel optimization framework demonstrates the efficiency and applicability of handling large-scale HEN synthesis problems. It can also guide engineers in the design of a large-scale HEN with lower costs and effort.

Optimal Shape Design of Direct-Drive Permanent Magnet Generator for 1 kW-Class Wind Turbines

Direct-drive permanent magnet generators are becoming an attractive option for highly efficient small-scale wind turbines due to their high-power density and size reduction capabilities. In this study, the optimal shape design of a direct-drive permanent magnet generator for 1 kW-class wind turbines was conducted while considering power generation and weight. Half of the geometry of a single stage in the generator was considered for a electromagnetic analysis under given electrical parameters. In order to construct a response surface model, a sensitivity analysis was conducted on seven design parameters of the proposed generator. The desirability function was used to minimize the weight of the generator while meeting a requirement of the target specification. The results indicated that the optimized design parameters for the generator met the target specification while maintaining the generator’s weight at the same level as the initial design model. From the comparisons with other research, the optimized generator exhibited a higher power generation/weight ratio than the generator with a rated capacity under 3 kW.

Comparative investigation and optimization of a direct cooling structure for the primary core and windings in permanent magnet synchronous linear motors

The permanent magnet synchronous linear motors with high acceleration and high thrust density are favored in many applications, but accompanied by a rapid temperature rise. This paper investigates a novel direct cooling structure for the primary core and windings, integrated with the advantage of a filler with high thermal conductivity. It can greatly reduce the thermal resistances between the heat source and the coolant and thus improves the cooling performance. Detailed numerical calculations and analysis are carried out to reveal the electromagnetic performance and thermal benefits of the direct cooling structure compared with the traditional back yoke cooling structure. In addition, an improved thermal network model is proposed with the help of numerical model. It can not only improve the calculation accuracy of the average winding temperature, but also predict the maximum temperature without additional computational burden. Furthermore, the improved thermal network model can be an initial design model to quickly optimize the direct cooling structure. Finally, experiments are conducted on a prototype to verify the excellent cooling performance of the proposed cooling structure and the effectiveness of the improved thermal network model.

Design and Multiobjective Optimization of a New Flux-Concentrating Rotor Combining Halbach PM Array and Spoke-Type IPM Machine

In this article, a new spoke-type interior permanent magnet (PM) with a flux-concentrating rotor is proposed. Based on the flux-concentrating principle, the fitting parameters between PMs and magnetic cores on the rotor make a significant impact on the flux concentration and saliency effect, thus resulting in the output torque and power capacity. Therefore, taking the average torque, cogging torque, peak power, and PM utilization as the optimization objectives, first, the sensitivity analysis is carried out that includes the different geometric variables of the rotor. Afterward, the response surface model based on the Box–Behnken method is established by selecting the reasonable optimization variables. Then, the optimal solution of the design parameters is verified by solving the response surface model. Meanwhile, a set of Pareto solutions is generated by adopting a multiobjective genetic algorithm. By two-dimensional finite-element analysis, the electromagnetic performance of a 72-slot/16-pole topology with the optimized flux-concentrating rotor is analyzed and compared with that of the initial design model. The results are demonstrated based on the response surface model. The effectiveness of the multiobjective optimization design method and multiobjective genetic algorithm is confirmed for the flux-concentrating rotor. Finally, a 30-kW prototype is developed and experimented with to verify the finite-element analysis results as well as the effectiveness of multiobjective optimization.

Dynamic calculation and optimization design of arbitrary planar branch piping system

The absorbing transfer matrix method (ATMM) is applied to dynamics calculation and optimization design of planar branch piping systems combined with the response surface model or method (RSM) and a new proposed hybrid RSM (HRSM). A main path is chosen to absorb the influences of sub-branches, and the branch point transfer matrix in the main transfer path is established and proved by the ANSYS simulation and experimental results. It shows that the errors between the ATMM and the finite element method are less than 0.36% in the calculation of the natural frequencies of the two-branch piping system, and the ATMM also agrees well with the dynamics response experimental results of the cross-branch piping system. Then, based on the initial design model of a double-branch piping system, first order natural frequency analysis samples are selected for the branch point positions optimization using the uniform design method (UD) and calculated by the ATMM; the minimum value of the RSM, obtained by fitting the samples with a second-order polynomial (SOP) function, is solved as the best design scheme using the genetic algorithm (GA). Finally, for the problem of supporting positions optimization of a T-branch piping system, a HRSM using the SOP function to fit the variation law with different supporting positions in the samples of the dynamics response optimization target, which is the total x-directional vibration acceleration level (TAC) of three supporting points in the frequency 1–300 Hz and the Fourier basis function to fit the relationship of SOP function error with independent variables is proposed combining the Minimize Prediction (MP) adding point criterion to gradually update the samples, until the HRSM reaches stability and obtains the wanted design solution.

In Silico Design and In Vitro Evaluation of Some Novel AMPs Derived From Human LL-37 as Potential Antimicrobial Agents for Keratitis.

The human body produces two classes of antimicrobial peptides (AMPs), namely defensins and cathelicidins. In this study, a novel decapeptide (Catoid) and its dimer (Dicatoid) based on human cathelicidin (LL-37) have been designed by bioinformatics tools to be used in the treatment of bacterial keratitis. After the selection and synthesis of peptide sequences, their antimicrobial activities against the standard and resistant strains of Pseudomonas aeruginosa and Staphylococcus aureus were evaluated. This test was performed with LL-37, gentamicin, ciprofloxacin, amikacin, and penicillin for a more accurate comparison. Furthermore, the cytotoxicity levels of the specified compounds on fibroblast cells and bovine corneal endothelial cells were investigated. The results demonstrated that the designed peptides had a superior antimicrobial activity on P. aeruginosa, compared to LL-37; however, Catoid had a better effect on the S. aureus strain. Additionally, a significant achievement is the very low toxicity level of Catoid and Dicatoid on the human skin fibroblast cell line and bovine corneal endothelial cells, compared to that of LL-37 as the initial design model.

Implementation and Optimization of Reverse Suspension Structure Design Model Using Deep Learning.

The present work aims to improve the design efficiency and optimize the results in the increasingly complex and diversified material design projects to help architects realize the better performance of building structures. According to the characteristics of comprehensive perception and intelligent processing of the Internet of Things, a reverse suspension structure design model is constructed based on the finite element method and simulated annealing algorithm. Besides, deep learning is adopted to train complex functions for performance correction and to optimize the plane structure of shell structure. Moreover, the force is transformed into shape, and the form-finding process is completed to facilitate the operation of designers. Finally, the spatial anchoring ability of the geographic information system is used to match and calculate the relevant characteristics of spatial elements. On this basis, the index construction strategy based on weight distribution is employed to realize the data fusion diagnosis framework and enhance the intelligence of architectural design. The simulation results show that the maximum tensile stress of the physical suspension experiment is 3.71 MPa and the maximum compressive stress is 14.7 MPa. The compressive stress value is much larger than the tensile stress value. The maximum deformation value's difference between the compressive and tensile stress is 0.07 and 0.11, respectively. The error is within the acceptable range, which is similar to the compression state results obtained from the actual suspension physical experiment, indicating that the initial design model of the reverse suspension structure based on deep learning is reliable. In addition, the evolutionary optimization effect analysis results demonstrate that the load of the design structure is relatively uniform, which verifies the feasibility of the algorithm reported here. The research significance of the reverse suspension structure model constructed here is to provide an accurate and feasible design idea for the reverse design of some complex structures in the building suspension. It can also shorten the creation and improvement cycle of this kind of structure and optimize the performance and construction cycle of the building structure.

Optimal Design of Spoke-Type IPM Motor Allowing Irreversible Demagnetization to Minimize PM Weight

In this study, we introduce an optimal design for a spoke-type interior permanent magnet (IPM) motor that can minimize PM weight by allowing irreversible demagnetization, unlike the conventional motor design method that does not allow irreversible demagnetization. The spoke-type rotor structure has the advantage of concentrating the magnetic flux around the rotor core. However, part of the PM near the surface of the stator tooth becomes sensitive to the armature reaction and external magnetic factors. Therefore, typical spoke-type rotor construction follows a limited design process that does not allow irreversible demagnetization. Although the manufacturing process allows tolerance for the demagnetization rate, motor design without considering the demagnetization rate in all the design stages becomes a design constraint and limits the performance area. In this study, the performance improvement is examined, when irreversible PM demagnetization is allowed up to −3%, and is not zero. For optimal design, Latin hypercube sampling (LHS), the kriging model, and genetic algorithm (GA) are utilized. With the proposed design process, motors are effectively designed to reduce the PM weight by 23.7%, compared to the initial design model while maintaining an efficiency almost similar to that of the initial design model.

Urban design assessment tools: a model for exploring atmospheres and situations

This paper aims to provide a theoretical framework for exploring the quality of affective atmospheres relevant to urban situations in city centre streets. This research study assumes that urban situations can shed light on how the urban form and everyday life experiences impact affective atmospheres. To examine this assumption, a snowballing technique was applied using the Google search engine and a systematic review of the SCImago database, identifying 21 books and 28 articles in 22 relevant journals. The results led to an initial urban design model exploring the perceptual quality of affective atmospheres in city centre streets. On the basis of the initial results, a model was built that proposes four dimensions and ten perceptual qualities and comprises visual, emotional (social experience), sensual (aesthetic experience) and spiritual design elements. The findings provide practical insight into the perceptual qualities of affective atmospheres through the integration of ten urban situations and five levels of urban design assessment tools. The concluding remarks highlight the role of the perceptual design dimensions shared by urban designers to present a model and framework with both reasonable and practical goals.

Optimisation of the design of a steel-welded pressure hull structure based on interactive nonlinear collapse strength analyses

ABSTRACT In this study, the genetic algorithm (GA) was implemented for the multi-objective optimization of the structural design of a pressure hull. The objective functions sought the maximum ultimate strength of the ring-stiffened cylindrical shell structure with minimum structural weight and maximum volume of the configured structural member. First, the evaluation models of several design variables of submarine structures were studied. Subsequently, a multi-objective GA algorithm was introduced. To improve the quality of the new population, several design constraints are applied. The final candidate structures were recomputed by non-linear finite element analysis (FEA) to observe the failure modes and compared with the initial design model. The results suggest that a lightweight construction would be achieved when a material with higher strength is used, especially for greater design depths

The Microclimate Design Process in Current African Development: The UEM Campus in Maputo, Mozambique

Even if current action towards sustainability in architecture mainly concerns single buildings, the responsibility of the urban shape on local microclimate has largely been ascertained. In fact, it heavily affects the energy performances of the buildings and their environmental behaviour. This produces the necessity to broaden the field of intervention toward the urban scale, involving in the process different disciplines, from architecture to fluid dynamics and physics. Following these ideas, the Masterplan for the Campus of the University Eduardo Mondlane in Maputo (Mozambique) develops a methodology that integrates microclimatic data and analyses from the initial design model. The already validated software ENVI-met (Version 4.4, ENVI_MET GmbH, Essen, Germany) acts as a useful ‘feedback’ tool that is able to assess the microclimatic behaviour of the design concept, also in terms of outdoor comfort. In particular, the analysis focused on the microclimatic performances of a ‘C’ block typology east oriented in relation to the existing buildings, in Maputo’s specific climatic characteristics. The initial urban proposal was gradually evaluated and modified in relation to the main critical aspects highlighted by the microclimatic analyses, in a sort of circular process that ended with a proposed solution ensuring better outdoor comfort than the existing buildings, and which provided an acceptable balance between spatial and climatic instances.

Lightweight Design of a Rear Axle Connection Bracket for a Heavy Commercial Vehicle by Using Topology Optimisation: A Case Study

An important design challenge of modern vehicles is mass reduction. Hence in many cases, mechanical design of vehicle components covers different optimization processes. One important structural optimization technique which is highly utilised in weight reduction applications is the topology optimization. This paper contains a multi-stage optimization based on the topology and design optimizations. During this study, the mechanical design of a rear axle-chassis connection bracket is achieved. First of all, the design load of the bracket was determined through a multibody dynamics analysis. This load case was determined among various driving conditions and the most critical load case was indicated as the design load of the bracket. This process was executed by using Adams/Car™ software. Subsequently, a design volume for the bracket was decided, which specifies the domain of topology optimization that will be employed later on. The determination of the design domain was made by considering the structural position of the design component, the neighbor components of the rear axle and the chassis. In this manner, the basic shape and dimensions of the bracket were created. The unnecessary volume of the draft design, which is not properly loaded under the design conditions was determined and removed from the design by means of topology optimization. The topology optimization was run in topology optimization module of ANSYS® Workbench 18.2 finite element analysis (FEA) software package. In the light of the primary shape obtained from the topology optimization study, a producible initial design model was built. This model was then subjected to FE analysis under the same circumstances with the draft model, in order to perform strength and deformation assessments of the initial design. Correspondingly, the critical regions were determined where stress concentrations were observed. The model was updated in a way that the stress values were reduced in these regions through the response surface methodology (RSM). The comparisons between the result and the initial geometries reveal that the mass of the connection bracket was reduced by 63%. Besides, the total deformation which was dropped by the design optimization is 13% lower than the initial design that was generated with the influence of topology optimization result.

Ultrasound Axicon: Systematic Approach to Optimize Focusing Resolution through Human Skull Bone.

The use of axicon lenses is useful in many high-resolution-focused ultrasound applications, such as mapping, detection, and have recently been extended to ultrasonic brain therapies. However, in order to achieve high spatial resolution with an axicon lens, it is necessary to adjust the separation, called stand-off (δ), between a conventional transducer and the lens attached to it. Comprehensive ultrasound simulations, using the open-source k-Wave toolbox, were performed for an axicon lens attached to a piezo-disc type transducer with a radius of 14 mm, and a frequency of about 0.5 MHz, that is within the range of optimal frequencies for transcranial transmission. The materials properties were measured, and the lens geometry was modelled. Hydrophone measurements were performed through a human skull phantom. We obtained an initial easygoing design model for the lens angle and optimal stand-off using relatively simple formulas. The skull is not an obstacle for focusing of ultrasound with optimized axicon lenses that achieve an identical resolution to spherical transducers, but with the advantage that the focusing distance is shortened. An adequate stand-off improves the lateral resolution of the acoustic beam by approximately 50%. The approach proposed provides an effective way of designing polydimethylsiloxane (PDMS)-based axicon lenses equipped transducers.

Topological Design of a Lightweight Sandwich Aircraft Spoiler.

In this study, a lightweight sandwich aircraft spoiler (AS) with a high stiffness-to-weight ratio was designed. Excellent mechanical properties were achieved by the synthetic use of topology optimization (TO), lattice structure techniques, and high-performance materials, i.e., titanium alloy and aluminum alloy. TO was first utilized to optimize the traditional aircraft spoiler to search for the stiffest structure with a limited material volume, where titanium alloy and aluminum alloy were used for key joints and other parts of the AS, respectively. We then empirically replaced the fine features inside the optimized AS with 3D kagome lattices to support the shell, resulting in a lightweight sandwich AS. Numerical simulations were conducted to show that the designed sandwich AS exhibited good mechanical properties, e.g., high bending rigidity, with a reduction in weight by approximately 80% when compared with that of the initial design model. Finally, we fabricated the designed model with photosensitive resin using a 3D printing technique.

AQbD Oriented New LC-ESI/MS Method for Quantification of Sirolimus in Drug and Spiked Plasma Sample

Background: The ICH guidelines Q8 (Analytical Quality by Design (AQbD) technique) give the procedure for optimization of analytical parameter involved method development and validation of Sirolimus (SL) in spiked Plasma and in dosage form by using advanced analytical technique. Objective: This research paper is based on Quality by Design (QbD) finalized conditions for a method for the determination of concentration of Sirolimus by using Liquid Chromatography–Tandem Mass Spectrometry (LC-ESI/MS). Method: Sirolimus is a potent immunosuppresant drug. Critical Process Attributes (CPA) is considered to be an influential parameter in separation, identification and quantification processes by UHPLC-ESIMS/ MS which are pH modifier,organic content, buffer strength, flow rate, Ionization chamber temperature, sheath gas, spray voltage and auxiliary gas that alters Critical Analytical Attributes (CAA), like peak area and Retention Time (Rt). These factors were evaluated first in a factorial design (TAGUCHI) and then extensively in a Central Composite Design (CCD) to zero-in on the mobile phase for the quantification of Sirolimus (SL) standard drug and along with its internal standard ( SL IS) in spiked plasma samples and in the formulation. Pareto chart from initial factorial design (Taguchi) model suggested for which of the CPA factors be given the importance that is to be exhaustively analyzed in the CCD and response surface analysis. An UHPLC instrument with the octadecylsilica column (C18 ) of dimensions (5 µm, 2.1 × 50 mm) was used and selectivity of the column was modified using methanol: water (65:35) methanol as an organic modifier as the mobile phase at a flow rate of 0.6 mL min-1. While spray voltage and Ionization chamber temperature for the method is maintained at the level predicted by the response analysis. Detection was performed using Triple quadrupole MS/MS by multiple-reaction monitoring via a positive electrospray ionization source. The ICH guidelines had elaborated about the parameters to be studied in method validation, i.e., selectivity, linearity, accuracy, precision repeatability system-suitability tests, method robustness,ruggedness, sensitivity and stability were accomplished. Results: The results are very clearly indicated that linearity with r value = 0.9980 in the concentration range of 10–500.0 ng mL-1, an intra- and inter-assay precision of 2.4 and 4.1%, respectively, and recovery studies were found to be between 100.8 and 105.6%. The lower limit of quantification was 0.086 ng/mL in 50 µL of human plasma sample. Conclusion: The present method gives a robust QbD-compliant quantitative UHPLC –ESI-MS/MS method for Sirolimus drug containing plasma samples (spiked). Keywords: AnalyticalQbD, sirolimus, LC-ESI/MS, response surface methodology, CCD technique, validation.

Limit Analysis of Thin-Wall Metal Frames Taking into Account their Foundations Rigidity

In this paper, the mathematical model of shakedown optimization problem of limit analysis for the thin-wall metal frames under variable quasi-static loads is presented. Authors assume the elastic-plastic flexural buckling in one plane without lateral torsional buckling behavior of members on conditions of the ideal elastic-plastic behaviour of the frames materials. According to Eurocodes requirements, the features of these frames taking into account rigidity of their foundations are described. There is problem with definition equivalent uniform moment factors for frames under variable quasi-static loads, because moment diagram is not constant. Classification of joints by stiffness was analyzed. The cases when the conditions of rigidity are not satisfied were described. The variants of solving tasks for thin-wall metal frames have been developed, for which there is a discrepancy between the classification by stiffness of the column base and the initial design model. It’s demonstrated on the principle scheme of the iteration process. With the help of numerical example, the problems which deal with classification of joints by stiffness on the final step of the optimal design of the thin-wall metal frames were performed.

다구찌 실험계획을 이용한 트랙터 캐빈 프레임의 최적설계

농업용 트랙터는 전도 사고 발생 시 운전자를 보호하기 위해 전도보호구조(ROPS: Roll Over Protective Structures)의 역할을 할 수 있어야 한다. 본 연구에서는 ROPS 강도시험 규격을 만족하는 트랙터 캐빈 프레임의 제작 기간과 비용을 줄이기 위해서 유한요소해석과 최적설계를 수행하였다. 해석 결과로부터 얻은 변위와 주 변형률의 크기를 통해 캐빈 프레임의 초기설계안은 ROPS 강도시험에 합격하는 것으로 나타났다. 또한 캐빈 프레임의 경량화 설계안을 도출하기 위하여 다구찌 실험계획을 이용해 최적설계를 수행하였다. 이를 통하여 캐빈 프레임 무게가 초기설계안보다 7% 저감된 최적설계안을 도출하였다. Agricultural tractors must have a function of ROPS to protect drivers under roll-over accident. In this study, finite element analyses and an optimal design were performed to reduce the cost and the production period of the cabin frame of a tractor to pass the ROPS strength test. To confirm the pass of ROPS strength test of an initial design model, the results of deformation and principal strain from the analyses were evaluated. To reduce the weight of the cabin frame, design of experiment of Taguchi was implemented, and an optimal design was obtained. The weight of the optimal design model was reduced by 7% comparing with the initial design model.

Automated generation of the computer-aided design model from the system structure for mechanical systems based on systems modeling language

The system-level structure model significantly affects the subsequent development process. However, such a model cannot be used directly due to its document-based representation. A significant gap exists between the system-level model and the detailed domain-specific model. The model integration method significantly facilitates the design scenario involving different design phases because it supports tasks such as complexity management and consistency maintenance. However, the automated generation of the computer-aided design model from the systems modeling language-based structure model of the mechanical system is a typical issue. In this study, a meta-model-based approach is proposed to generate the initial computer-aided design model represented by the STEP file from the systems modeling language-based system structure model. A geometry-related system structure modeling method is described, and the triple graph grammar is introduced to transform the systems modeling language model into the EXPRESS model. An automated generation algorithm is proposed to construct the initial computer-aided design model for mechanical systems against the ISO 10303-203 (AP 203) standard by parsing the EXPRESS model. Our approach facilitates model integration and helps reduce the gap between the system-level structure model and the computer-aided design model. This reduction would be beneficial for eliminating misunderstandings between different designers and thus to accelerate the design process. Finally, an example of an engine is provided to illustrate the proposed method.

평행방향/할박 자화 영구자석을 갖는 마그네틱 기어의 설계변수에 따른 토크특성 해석 및 비교

Magnetic gear can transmit torque without any mechanical contact among rotational parts in rotating mechanical systems. Especially, magnetic gear using rare-earth PMs can be used in variety of industry application because of their great power efficiency. Thus, recent trend shows that magnetic gear can be replaced with common mechanical gear. This paper deals with comparison and torque analysis for magnetic gears with parallel and Halbach magnetization according to various design parameters. Using a two dimensional (2D) finite element (FE) analysis, suitable gear ratio is selected. We performed analysis for magnetically connected inner and outer torque with respect to various design parameters including thickness of inner and outer PM, steel pole angle, segments of Halbach array and magnetization pattern of inner and outer PMs. Finally, we can obtain improved design model having parallel and Halbach magnetization with larger torque, compared with an initial design model.