Analysis of a Metal Matrix Composites Automotive Component

This study presents an implementation of concurrent engineering (CE) and an analytical network process to form a new rating method as part of the manufacturing process and material analysis in the product development environment. The proposed procedure is referred to as a concurrent network (CN). It is planned for CN to carry out simultaneous analysis of all aspects of product elements by using CE strategy. Furthermore, CN enables interdependence and interrelationship analysis between product elements by implementing ANP. In this study, CN is utilized for the manufacturing process and material analysis of a metal matrix composites (MMCs) automotive component which is the brake disc. The results show that by using CN, all the product parameters can be analyzed comprehensively and the importance weights of the product parameters with regard to the MMCs brake disc performance are obtained. It is concluded that in the manufacturing process cluster the primary process parameter has the highest score, while in the material cluster the ranking is dominated by mechanical properties. This means that these sub-conceptual parameters are the most important ones to consider in order to achieve the required performance of the product

Exploring Women's Retirement Literature through Bibliometric Analysis Using VOSviewer

This paper aims to analyse the issue of women’s retirement (WR) literature through bibliometric analysis using VOSviewer, a programme for the visualisation of similarities (VOS). Publications focusing on women’s retirement were compiled from the Scopus database, with a total of 393 items spanning the years 1965 to 2021. The most prolific nations for retirement literature are the United States, United Kingdom, and Sweden, which reflects the affiliation analysis that correlates highly with published papers within specific institutions in those three countries. The issues were discussed within the context of social sciences, economics, econometrics, and finance, as well as psychology. This suggests an interlinking of women’s retirement with social and financial issues that might contribute towards psychological challenges for women. The most cited keywords, among others, are ‘retirement’, ‘women’ and ‘pension’, with thematic clusters being linked to ‘ageing’ and ‘health’. These could be linked to health problems that emerge because of ageing, and thus might be linked to the retirement wellbeing of women. The findings of this paper shed light on several implications that can be used as a guideline for researchers and act as a foundation before embarking on the emerging knowledge areas of women’s retirement

2D and 3D Complexity Analysis on MRI Images using Fractal Dimension

The brain, which is the most complex structure in the human body, has attracted attention of many researchers to study the possible fractal analysis application upon it. Current interest is seen directed more towards the utilization of complexity analysis as measured by fractal dimension in determining the pathologies effect and degenerative factor on the brain structure volume. In this paper, we used two boxcounting methods: average 2D Fractal Dimension and 3D Fractal Dimension. 47 subjects (19 males, 28 females), aged ranging from 21 to 25 years, were recruited. Brain MRI images were acquired by using 3T MRI system. The images were then thresholded according to Otsu’s method. The processed images were then calculated using fractal analysis, and the values obtained were statistically evaluated using Pearson’s correlation test (r2 = -0.106, p = 0.477). In conclusion, no correlation was seen between average 2D FD and 3D FD

Microstrip to Parallel-Strip Nonlinear Transition Balun with Stubs and DGS for UWB Dipole Antenna

Three tapered baluns with nonlinear transition are developed for harmonic suppression in dipole antenna. The first balun consists of an exponential profile with the size of a quarter–wavelength for both the height and width with a wideband characteristic. However, for some applications such as narrowband harmonic suppression antennas and wideband-to-narrowband reconfigurable antennas, the suppression of higher operating band is desired. By employing stubs-filter and a defected ground structure (DGS), two narrowband tapered baluns are produced. They are named as an exponential balun-stub and an exponential balun-DGS, respectively, that operate from 1 to 2 GHz. A simulated and measured results that based on the reflection coefficient is found to be better than -10 dB from 1 to 2 GHz. The employment of the stubs and DGS have enabled these baluns to have the capability to reject the unwanted higher frequency band from 2.0 to 10 GHz. Finally, the proposed baluns are employed as a feeding circuit for an ultra wideband (UWB) circular dipole antenna that produces a reasonable outcome

An investigation of geometrical defect of cold embossing part utilizing FEM and image processing technique

Accuracy of the forging parts becomes critical as the process depends on many factors. Defect may harm the assembly and tends to affect the performance of the parts. Therefore, it must be understood and detected as soon as the manufacturing begins. The size and complexity of the part limit the defect to be assessed. This study intent to investigate the defect of the cold embossing pin located at the head of a propeller blade. This is to ensure accurate assembly of the blade. In this work, the effects of design and process parameters on the formation of defect are studied using 2-D finite element analysis. The defect can be measured based on the incomplete filling of the region using the captured images from the FE result. The results seem to show that there is less effect from the diameter of punch and internal cavity, but more obvious due to the distance to the edge. The FE results are in good agreement with the experimental results

The mechanical performance of sugar palm fibres (Ijuk) reinforced phenolic composites

Sugar palm fibres are one of the natural fibres which have many features and need further study to understand their properties. The aim of this work is to investigate the flexural, compressive and impact properties of sugar palm fibres reinforced phenolic composites. Sugar palm fibres were used as a filler (particle size 150 μm) and with loading of 0, 10, 20, 30, and 40 vol.%. The fibres were treated by sea water and then fabricated into composites by hot press technique. Flexural, compressive, and impact tests were carried out as per ASTM D790, ASTM D695-08a, and ASTM D256 standards, respectively. Scanning electron microscopy (SEM) was used to investigate the morphology and the interfacial bonding of the fibres-matrix in composites. The results show that the mechanical properties of the composites improve with the incorporation of fibres. The composite of 30 vol.% particle loading exhibit optimum values which are 32.23 MPa, 61.66 MPa, and 4.12 kJ/m2 for flexural, compressive, and impact strength, respectively. This was because good compatibility of fibre-matrix bonding. Consequently, sugar palm fibre is one of the prospective fibres and could be used as a potential resource to reinforcement polymer composite

Determination of the tensile properties and biodegradability of cornstarch-based biopolymers plasticized with sorbitol and glycerol

In this study, the effects of various quantities of sorbitol and glycerol plasticizers (0%, 30%, 45%, and 60%) on cornstarch-based film were examined to develop a novel polymer for usage with biodegradable materials. The film was prepared using the casting process. According to the test findings, the application of the plasticizer concentrations affected the thickness, moisture content, and water absorption of the film. When plasticizer concentrations were increased to 60%, the tensile stress and Young’s modulus of plasticized films dropped regardless of plasticizer type. However, the thin film with addition of 30% sorbitol plasticizer demonstrated a steady value of Young’s modulus (60.17 MPa) with an increase in tensile strength (13.61 MPa) of 46%, while the lowest combination of tensile strength and Young’s modulus is the film that was plasticized with 60% glycerol, with 2.33 MPa and 16.23 MPa, respectively. In summary, the properties and performance of cornstarch-based film were greatly influenced by plasticizer types and concentrations. The finest set of features in this research appeared in the film plasticized with 30% sorbitol, which achieved the best mechanical properties for food packaging applications

Evaluation On Compression Properties Of Different Shape And Perforated rHDPE In Concrete Structures

The purpose of this study was to develop a concrete structure by incorporating waste HDPE plastic as the main reinforcement material and cement as the matrix via standard casting technique. There are eight different shapes of rHDPE reinforcing structure were used to investigate the compression properties of produced concrete composites. Experimental result shown that the highest shape in compressive strength of rHDPE reinforcing structure were the concrete with the addition of X-perforated beam (18.22 MPa), followed by X-beam (17.7 MPa), square perforated tube (17.54 MPa), round tube (17.42 MPa) and round perforated tube (16.69 MPa). In terms of their compressive behavior, the average concrete containing rHDPE reinforcement was successfully improved by 6 % of the mechanical characteristic compared to control concrete. It is shown that the addition of waste plastic as reinforcement structure can provide better compressive strength based on their shape and pattern respectively

Effect of fiber content and their hybridization on bending and torsional strength of hybrid epoxy composites reinforced with carbon and sugar palm fibers

This study aims to investigate the effect of fiber hybridization of sugar palm yarn fiber with carbon fiber reinforced epoxy composites. In this work, sugar palm yarn composites were reinforced with epoxy at varying fiber loads of 5, 10, 15, and 20 wt % using the hand lay-up process. The hybrid composites were fabricated from two types of fabric: sugar palm yarn of 250 tex and carbon fiber as the reinforcements, and epoxy resin as the matrix. The ratios of 85: 15 and 80: 20 were selected for the ratio between the matrix and reinforcement in the hybrid composite. The ratios of 50: 50 and 60: 40 were selected for the ratio between sugar palm yarn and carbon fiber. The mechanical properties of the composites were characterized according to the flexural test (ASTM D790) and torsion test (ASTM D5279). It was found that the increasing flexural and torsion properties of the non-hybrid composite at fiber loading of 15 wt % were 7.40% and 75.61%, respectively, compared to other fiber loading composites. For hybrid composites, the experimental results reveal that the highest flexural and torsion properties were achieved at the ratio of 85/15 reinforcement and 60/40 for the fiber ratio of hybrid sugar palm yarn/carbon fiber-reinforced composites. The results from this study suggest that the hybrid composite has a better performance regarding both flexural and torsion properties. The different ratio between matrix and reinforcement has a significant effect on the performance of sugar palm composites. It can be concluded that this type of composite can be utilized for beam, construction applications, and automotive components that demand high flexural strength and high torsional forces

Vestibular and balance dysfunction in children with congenital CMV: a systematic review.

OBJECTIVE: This systematic review evaluates vestibular and balance dysfunction in children with congenital cytomegalovirus (cCMV), makes recommendations for clinical practice and informs future research priorities. DESIGN: MEDLINE, Embase, EMCARE, BMJ Best Practice, Cochrane Library, DynaMed Plus and UpToDate were searched from inception to 20 March 2021 and graded according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. PATIENTS: Children with cCMV diagnosed within 3 weeks of life from either blood, saliva and/or urine (using either PCR or culture). INTERVENTION: Studies of vestibular function and/or balance assessments. MAIN OUTCOME MEASURES: Vestibular function and balance. RESULTS: 1371 studies were identified, and subsequently 16 observational studies were eligible for analysis, leading to an overall cohort of 600 children with cCMV. All studies were of low/moderate quality. In 12/16 studies, vestibular function tests were performed. 10/12 reported vestibular dysfunction in ≥40% of children with cCMV. Three studies compared outcomes for children with symptomatic or asymptomatic cCMV at birth; vestibular dysfunction was more frequently reported in children with symptomatic (22%-60%), than asymptomatic cCMV (0%-12.5%). Two studies found that vestibular function deteriorated over time: one in children (mean age 7.2 months) over 10 months and the other (mean age 34.7 months) over 26 months. CONCLUSIONS: Vestibular dysfunction is found in children with symptomatic and asymptomatic cCMV and in those with and without hearing loss. Audiovestibular assessments should be performed as part of neurodevelopmental follow-up in children with cCMV. Case-controlled longitudinal studies are required to more precisely characterise vestibular dysfunction and help determine the efficacy of early supportive interventions. PROSPERO REGISTRATION: CRD42019131656