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Wind tunnel and numerical data on the ventilation performance of windcatcher with wing wall

Nejat P, Calautit JK, Abd Majid MZ, Hughes BR, Zeynali I, Jomehzadeh F

Data Brief, 2016 Dec;9:448-452.
PMID: 27709121

The data presented in this article were the basis for the study reported in the research articles entitled "Evaluation of a two-sided windcatcher integrated with wing wall (as a new design) and comparison with a conventional windcatcher" (P. Nejat, J.K. Calautit, M.Z.A. Majid, B.R. Hughes, I. Zeynali, F. Jomehzadeh, 2016) [1] which presents the effect of wing wall on the air flow distribution under using the windcatchers as a natural ventilation equipment. Here, we detail the wind tunnel testing and numerical set-up used for obtaining the data on ventilation rates and indoor airflow distribution inside a test room with a two-sided windcatcher and wing wall. Three models were integrated with wing wall angled at 30°, 45° and 60° and another windcatcher was a conventional two-sided device. The computer-aided design (CAD) three-dimensional geometries which were produced using Solid Edge modeler are also included in the data article.

Matched MeSH terms: Computer-Aided Design
Fulltext An alternate method to springback compensation for sheet metal forming

Siswanto WA, Anggono AD, Omar B, Jusoff K

ScientificWorldJournal, 2014;2014:301271.
PMID: 25165738 DOI: 10.1155/2014/301271

The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range.

Matched MeSH terms: Computer-Aided Design*
Fulltext PCB drill path optimization by combinatorial cuckoo search algorithm

Lim WC, Kanagaraj G, Ponnambalam SG

ScientificWorldJournal, 2014;2014:264518.
PMID: 24707198 DOI: 10.1155/2014/264518

Optimization of drill path can lead to significant reduction in machining time which directly improves productivity of manufacturing systems. In a batch production of a large number of items to be drilled such as printed circuit boards (PCB), the travel time of the drilling device is a significant portion of the overall manufacturing process. To increase PCB manufacturing productivity and to reduce production costs, a good option is to minimize the drill path route using an optimization algorithm. This paper reports a combinatorial cuckoo search algorithm for solving drill path optimization problem. The performance of the proposed algorithm is tested and verified with three case studies from the literature. The computational experience conducted in this research indicates that the proposed algorithm is capable of efficiently finding the optimal path for PCB holes drilling process.

Matched MeSH terms: Computer-Aided Design/instrumentation*
Evaluation of the color stability of temporary materials produced with CAD/CAM

Kul E, Abdulrahim R, Bayındır F, Matori KA, Gül P

Dent Med Probl, 2021 5 14;58(2):187-191.
PMID: 33982454 DOI: 10.17219/dmp/126745

BACKGROUND: If a temporary restoration is in the esthetic area and needs to be worn for a long time, the color stability of temporary materials becomes an important factor.
OBJECTIVES: The aim of this in vitro study was to evaluate the long-term effects of various staining solutions on the color stability of different temporary materials produced with the computer-aided design and computer-aided manufacturing (CAD/CAM) technology.
MATERIAL AND METHODS: In the study, the following materials were used: VITA CAD-Temp® (group 1); Ceramill® Temp (group 2); and Telio® CAD (group 3). Forty disk-shaped specimens (10 mm in diameter, 2 mm in thickness) of each material (N = 120) were produced with a CAD/CAM system. Staining solutions - of tea (A), of coffee (B) and cola (C) - and distilled water (D, control) were used, and color was evaluated before and after storing the samples in the solutions. Measurements were taken with a spectrophotometer and the color parameters (L*, a*, b*, and ΔE) were calculated according to the Commission internationale de l'éclairage system (CIELab). The results were evaluated with the two-way analysis of variance (ANOVA) and Tukey's tests (α = 0.05).
RESULTS: Clinically perceivable (ΔE00 > 0.8) and statistically significant (p < 0.001) color differences were detected in all specimens. The highest ΔE00 value was found in the Ceramill Temp specimens. In addition, the highest ΔE00 values were noted for the specimens stored in cola and the coffee solution for all groups. The lowest ΔE00 value was observed for the groups stored in the tea solution.
CONCLUSIONS: Clinically perceivable color changes were observed in all the specimens kept in the solutions. Color changes were greater for cola and coffee as compared to tea.

Matched MeSH terms: Computer-Aided Design*
Designing 3D prosthetic templates for maxillofacial defect rehabilitation: A comparative analysis of different virtual workflows

Farook TH, Jamayet NB, Abdullah JY, Asif JA, Rajion ZA, Alam MK

Comput Biol Med, 2020 03;118:103646.
PMID: 32174323 DOI: 10.1016/j.compbiomed.2020.103646

OBJECTIVE: To design and compare the outcome of commercial (CS) and open source (OS) software-based 3D prosthetic templates for rehabilitation of maxillofacial defects using a low powered personal computer setup.
METHOD: Medical image data for five types of defects were selected, segmented, converted and decimated to 3D polygon models on a personal computer. The models were transferred to a computer aided design (CAD) software which aided in designing the prosthesis according to the virtual models. Two templates were designed for each defect, one by an OS (free) system and one by CS. The parameters for analyses were the virtual volume, Dice similarity coefficient (DSC) and Hausdorff's distance (HD) and were executed by the OS point cloud comparison tool.
RESULT: There was no significant difference (p > 0.05) between CS and OS when comparing the volume of the template outputs. While HD was within 0.05-4.33 mm, evaluation of the percentage similarity and spatial overlap following the DSC showed an average similarity of 67.7% between the two groups. The highest similarity was with orbito-facial prostheses (88.5%) and the lowest with facial plate prosthetics (28.7%).
CONCLUSION: Although CS and OS pipelines are capable of producing templates which are aesthetically and volumetrically similar, there are slight comparative discrepancies in the landmark position and spatial overlap. This is dependent on the software, associated commands and experienced decision-making. CAD-based templates can be planned on current personal computers following appropriate decimation.

Matched MeSH terms: Computer-Aided Design*
Modeling and Simulation of Two Wheelchair Accessories for Pushing Doors

Abdullah SJ, Shaikh Mohammed J

Assist Technol, 2018;30(4):165-175.
PMID: 28346064 DOI: 10.1080/10400435.2017.1293193

Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.

Matched MeSH terms: Computer-Aided Design*