Pub Date : 2022-06-01DOI: 10.17159/2309-8988/2022/v38a2
J. van Santen, C. Coetzee
This project entailed the design, manufacture, and testing of a test setup with the ability to measure all load components acting on tillage and planting implements. In future, data obtained with the test setup can be used to perform accurate design calculations, as input into finite element simulations, and to perform accurate fatigue analysis. The design of implements can therefore be improved to better withstand the loads under various operational conditions and to minimise fatigue cracking. Laboratory controlled testing, and subsequent field tests, proved that the designed test setup was able to isolate and accurately measure each of the three orthogonal load components, as well as the main moment. It was further shown that the remaining two moments could be accurately calculated using the measured load components and fixed geometric lengths. The conclusion was drawn, based on field tests, that an increase in speed with the tine ripper had no significant effect on the mean load. Further, an increase in the working depth, resulted in an increase in the load, especially in the draught and vertical directions. Finally, it was shown that a decrease in turning radius (a tighter turn), resulted in an increase in the lateral force component.
{"title":"Design of a Test Setup for Measuring all Load Components Acting on Tillage and Planting Implements","authors":"J. van Santen, C. Coetzee","doi":"10.17159/2309-8988/2022/v38a2","DOIUrl":"https://doi.org/10.17159/2309-8988/2022/v38a2","url":null,"abstract":"This project entailed the design, manufacture, and testing of a test setup with the ability to measure all load components acting on tillage and planting implements. In future, data obtained with the test setup can be used to perform accurate design calculations, as input into finite element simulations, and to perform accurate fatigue analysis. The design of implements can therefore be improved to better withstand the loads under various operational conditions and to minimise fatigue cracking. Laboratory controlled testing, and subsequent field tests, proved that the designed test setup was able to isolate and accurately measure each of the three orthogonal load components, as well as the main moment. It was further shown that the remaining two moments could be accurately calculated using the measured load components and fixed geometric lengths. The conclusion was drawn, based on field tests, that an increase in speed with the tine ripper had no significant effect on the mean load. Further, an increase in the working depth, resulted in an increase in the load, especially in the draught and vertical directions. Finally, it was shown that a decrease in turning radius (a tighter turn), resulted in an increase in the lateral force component.","PeriodicalId":331389,"journal":{"name":"R&D Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116322443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.17159/2309-8988/2022/v38a1
G. Bekker, C. Meyer, S. J. van der Spuy
This study investigates the potential gains in operating volume flow rate and static efficiency of an induced draught axial flow fan system. These gains are achieved through pressure recovery, i.e. the conversion of dynamic pressure at the fan exit into static pressure. Pressure recovery is achieved using downstream diffusers, stator blade rows, and combinations of these. Three different diffuser lengths are considered. Of the shortest diffusers, a conical diffuser increases the operating volume flow rate by 3.2 % and the fan static efficiency by 9.8 % (absolute). A longer conical diffuser increases it by 3.9 % and 11.9 %, respectively. Of the longest diffusers, an annular diffuser increases the flow rate by 5.5 % and the fan static efficiency by 16.8 %.
{"title":"Pressure Recovery Discharge Configurations for an Induced Draught Axial Flow Fan","authors":"G. Bekker, C. Meyer, S. J. van der Spuy","doi":"10.17159/2309-8988/2022/v38a1","DOIUrl":"https://doi.org/10.17159/2309-8988/2022/v38a1","url":null,"abstract":"This study investigates the potential gains in operating volume flow rate and static efficiency of an induced draught axial flow fan system. These gains are achieved through pressure recovery, i.e. the conversion of dynamic pressure at the fan exit into static pressure. Pressure recovery is achieved using downstream diffusers, stator blade rows, and combinations of these. Three different diffuser lengths are considered. Of the shortest diffusers, a conical diffuser increases the operating volume flow rate by 3.2 % and the fan static efficiency by 9.8 % (absolute). A longer conical diffuser increases it by 3.9 % and 11.9 %, respectively. Of the longest diffusers, an annular diffuser increases the flow rate by 5.5 % and the fan static efficiency by 16.8 %.","PeriodicalId":331389,"journal":{"name":"R&D Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123939031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.17159/2309-8988/2019/v39a1
P. Dabee, B. Rajkumarsingh, Y. Beeharry
Surface dust can be a source carrier of viruses, bacteria and air pollution which entail common health issues such as asthma attacks, chest tightness, wheezing and difficulty in breathing. Visually perceived, cleanliness is one measure of indoor air quality and is the subjective assessment of cleaning quality. The aim of this work is to use pattern recognition mediated through a mobile application to analyse and classify dust in households, in order to obtain useful information about the dust sources for the selection of appropriate countermeasures in view to improve air quality and better manage the cleaning of indoor surfaces. The dust type categorization in this work are pollen, rock and ash. This paper also explores the concept of transfer learning techniques and adopts it for small particle classification using CNN models by developing a surface dust application for android smartphones. The behaviour of InceptionV2, InceptionV3, ResNetV2, MobileNetV2 and MobileNetV3 as dust feature extractors were analysed based on their accuracy, precision, recall and Fl-Scoreperformance metrics. Results show that MobileNetV3 model is best suited as a dust feature extractor and rapid dust prediction with an accuracy of up to 92% and low-size storage of only 30 megabytes. Additional Keywords: Android; Classification; Transfer Learning; Smartphone; Surface dust.
{"title":"An Android Application-based Surface Oust Classifier","authors":"P. Dabee, B. Rajkumarsingh, Y. Beeharry","doi":"10.17159/2309-8988/2019/v39a1","DOIUrl":"https://doi.org/10.17159/2309-8988/2019/v39a1","url":null,"abstract":"Surface dust can be a source carrier of viruses, bacteria and air pollution which entail common health issues such as asthma attacks, chest tightness, wheezing and difficulty in breathing. Visually perceived, cleanliness is one measure of indoor air quality and is the subjective assessment of cleaning quality. The aim of this work is to use pattern recognition mediated through a mobile application to analyse and classify dust in households, in order to obtain useful information about the dust sources for the selection of appropriate countermeasures in view to improve air quality and better manage the cleaning of indoor surfaces. The dust type categorization in this work are pollen, rock and ash. This paper also explores the concept of transfer learning techniques and adopts it for small particle classification using CNN models by developing a surface dust application for android smartphones. The behaviour of InceptionV2, InceptionV3, ResNetV2, MobileNetV2 and MobileNetV3 as dust feature extractors were analysed based on their accuracy, precision, recall and Fl-Scoreperformance metrics. Results show that MobileNetV3 model is best suited as a dust feature extractor and rapid dust prediction with an accuracy of up to 92% and low-size storage of only 30 megabytes. Additional Keywords: Android; Classification; Transfer Learning; Smartphone; Surface dust.","PeriodicalId":331389,"journal":{"name":"R&D Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134239951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.17159/2309-8988/2022/v38a4
I. Botha, G. Bright, J. Collins
The purpose of this study was the development and experimental validation of a novel portable tactile braille reading device. This design aimed to address the lack of quality braille reading material in South African schools dedicated to the blind and visually impaired. The design was divided into four subsystems: the actuation of the refreshable braille display, the mechanical design of the hand mounted device, the Optical Character Recognition (OCR) software and the electronic control system. The objectives of the study included the design of the electrical, mechanical and software subsystems of the device with emphasis on miniaturisation and a low-cost design, as well as the experimental validation of the haptic feedback and OCR subsystems. The system validation focussed on the experimental analysis of the OCR software design and the Dielectric Elastomer Actuators (DEAs) utilised in the refreshable display. The performance of low-cost elastomer and electrode materials were experimentally assessed during the design of the miniature DEAs. The ideal material combination for the proposed application was identified as a VHB4910 acrylic film lined with MG Chemicals 846 carbon grease. The largest vertical deflections of the diaphragm-type DEA were attained with a stipple-based electrode application, with the elastomer prestrained to 300 % initial area. The OCR program analysis indicated that multiple character recognition was more efficient and less prone to inaccuracies than the initially proposed single character recognition method. The integration of OCR software with miniature DEAs served as a novel approach to text-to-braille transcription.
{"title":"Dielectric Elastomer Actuators and Optical Character Recognition in a Braille Display","authors":"I. Botha, G. Bright, J. Collins","doi":"10.17159/2309-8988/2022/v38a4","DOIUrl":"https://doi.org/10.17159/2309-8988/2022/v38a4","url":null,"abstract":"The purpose of this study was the development and experimental validation of a novel portable tactile braille reading device. This design aimed to address the lack of quality braille reading material in South African schools dedicated to the blind and visually impaired. The design was divided into four subsystems: the actuation of the refreshable braille display, the mechanical design of the hand mounted device, the Optical Character Recognition (OCR) software and the electronic control system. The objectives of the study included the design of the electrical, mechanical and software subsystems of the device with emphasis on miniaturisation and a low-cost design, as well as the experimental validation of the haptic feedback and OCR subsystems. The system validation focussed on the experimental analysis of the OCR software design and the Dielectric Elastomer Actuators (DEAs) utilised in the refreshable display. The performance of low-cost elastomer and electrode materials were experimentally assessed during the design of the miniature DEAs. The ideal material combination for the proposed application was identified as a VHB4910 acrylic film lined with MG Chemicals 846 carbon grease. The largest vertical deflections of the diaphragm-type DEA were attained with a stipple-based electrode application, with the elastomer prestrained to 300 % initial area. The OCR program analysis indicated that multiple character recognition was more efficient and less prone to inaccuracies than the initially proposed single character recognition method. The integration of OCR software with miniature DEAs served as a novel approach to text-to-braille transcription.","PeriodicalId":331389,"journal":{"name":"R&D Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115863303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.17159/2309-8988/2022/v38a3
C. D. du Plessis, S. J. van der Spuy, H. Reuter
Axial flow fans are fundamental to air-cooled condensers. While they provide the air flow for heat transfer, they also generate noise, which is a growing environmental concern. Sound reflections are characterised in an existing fan performance test facility, which does not conform to fan noise measurement standards. Corrections to the measured SPL spectrum is deduced along with the uncertainty in noise measurements. Corrections are compared to a reflection correction standard relating to buildings. This methodology can be repeated for other fan test facilities which do not comply with noise measurement standards.
{"title":"Characterisation of a Standard Fan Test Facility to Accommodate Reflection of Sound During Noise Measurements","authors":"C. D. du Plessis, S. J. van der Spuy, H. Reuter","doi":"10.17159/2309-8988/2022/v38a3","DOIUrl":"https://doi.org/10.17159/2309-8988/2022/v38a3","url":null,"abstract":"Axial flow fans are fundamental to air-cooled condensers. While they provide the air flow for heat transfer, they also generate noise, which is a growing environmental concern. Sound reflections are characterised in an existing fan performance test facility, which does not conform to fan noise measurement standards. Corrections to the measured SPL spectrum is deduced along with the uncertainty in noise measurements. Corrections are compared to a reflection correction standard relating to buildings. This methodology can be repeated for other fan test facilities which do not comply with noise measurement standards.","PeriodicalId":331389,"journal":{"name":"R&D Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124399475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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