Development of waste coir-reinforced aluminum matrix automotive brake pad material

High friction and low wear are the prime functional properties of a brake pad material. Therefore main ingredients of brake pad materials are filler or reinforcement material, binder, friction modifiers, abrasive material and solid lubricant. There is a growing tendency to replace the asbestos filler in brake friction materials. Therefore, this paper presents a new development of waste-reinforced aluminum matrix automotive brake pad materials with a view to replace the use of asbestos whose dust is carcinogenic and has a harmful effect to the human life. In this research, five different laboratory formulations were selected with varying waste coir fiber as reinforcement consists of 0, 5, 10, 15, and 20 volume fraction along with binder, friction modifiers, abrasive material and solid lubricant using powder metallurgy technique. The coir fibre reinforced composite sample with a size of 25 mm x 25 mm x 6 mm was fabricated for physio-mechanical and tribological testing. The density and microstructural analysis were performed using densometer and SEM respectively whereas, hardness and compressive tests were done using hardness and universal testing machine respectively. The CHASE Dynamometer machine in accordance with Society of Automotive Engineer standard procedure SAE J661 was employed for tribological properties of the developed brake pad materials. From the study it was observed that two formulations with 5 and 10% volume fraction waste coir fibre were able to show better properties in terms of physico-mechanical, wear and friction compared to other formulations. The microstructure reveals uniform distribution of constituent’s materials along with the coir fiber in the morphology. It can be concluded that the new coir fibre (up to 10%) might be suitable for better physico-mechanical and tribological properties. Hence, waste coir fiber can be used as a candidate fibre or filler material for the mass-scale fabrication of asbestos-free brake pad without any harmful effect. Keywords: Coir fiber, Brake pad, Density, Hardness, Compressive Strength, Microstructure, Friction coefficient and Wear

Tanggung Jawab Sosial Universitas dan Tata Kelola Universitas Terhadap Citra UIN Syarif Hidayatullah Jakarta

This research aims to examine that University Social Responsibility (USR) and Good University Governance (GUG) influence toward image of UIN Syarif Hidayatullah Jakarta. Indicator of USR include economic responsibilities, legal responsibilities, ethical responsibilities and philanthrophic responsibilities. Indicator of GUG include transparation, accountability, responsibility, independency, fairness and participation. Indicator of Image include Reputation, Personality, ethical/value and corporate identity. Sample of this research include civitas academic of UIN Syarif Hidayatullah Jakarta include student, lecturer and officer. Technic analysis data use multiple linear regression. Results of this research as partial provide evidence that University Social Responsibility influence toward image of UIN Syarif Hidayatullah Jakarta, and Good University Governance influence toward image of UIN Syarif Hidayatullah Jakarta

Sistem Informasi Logistik Stock Opname Menggunakan Quick Response Code Berbasis Android

Sistem  Informasi  Logistik  Stock  Opname  memberikan  informasi  mengenai  barang  yang  terdapat di gudang antara lain jumlah tiap barang dan detail barang berupa merk dan nomor seri barang. Informasi tersebut ditampilkan secara mobile melalui aplikasi yang berbasis sistem operasi Android. Bagian utama proses logistik yang  berpengaruh  besar  pada  Perusahaan  yang  menerapkannya  adalah  stock  opname.  Stock  opname  adalah proses  menghitung  jumlah  barang  yang  ada  di  gudang  dan  mencocokkannya dengan  catatan pembukuan persediaan. Proses tersebut dipermudah dengan menggunakan QR (Quick Response) Code yang diaplikasikan kedalam  sistem  operasi  Android  sehingga  proses  stock  opname  tidak  lagi  dilakukan  secara  manual.  Dalam system ini juga terdapat tampilan web untuk admin yang berguna untuk menampilkan dan mengolah semua data barang termasuk hasil stock opname yang sudah dilakukan. Selain itu, juga disediakan fitur search dan filter data untuk  memudahkan  pencarian  barang  dan  fitur  untuk  mencetak  laporan  dari  data  tersebut. Terdapat fitur transaksi  masuk  dan  transaksi  keluar  sebagai  proses  untuk  melakukan  pembelian  barang  dari  supplier  dan penjualan barang kepada bengkel yang membutuhkan

6 MV photon beam induced UV/VIS absorption of hema polymer gel

The aim of this study was to evaluate properties of normoxic polymer gel 2-Hydroxyethyl methacrylate monomer (HEMAG) as a point dosimeter by using optical properties evaluation techniques. HEMAG were prepared from seven different radiation dose within five different depths of HEMAG dosimeters. These HEMAG dosimeters were irradiated by linear accelerator with 6 MV photon beams. The absorption spectra were measured by using a UV-visible spectrophotometer in the wavelength range from 300 to 800 nm. Then, the data was analysed to determine the optical energy band gap (Eg) and Urbach’s energy (ΔE). The result showed that Eg and ΔE were dependent on radiation dose and percentage of depth dose (PDD). In additional, Eg with indirect transition of HEMAG decreased as radiation dose increased and increased with traversing of depth. ΔE of HEMAG increased as the dose increased and decreased with traversing depth of monomer. There was a shift in the Eg values towards lower energy as the dose increased and led to a shift of the ΔE value towards the higher energy with increasing dose. This observation supported the increase of structured disorder of the polymer with increasing radiation dose, which resulted in the lower energy transitions that was feasible and reduced the values of Eg. In conclusion, HEMAG has a potential to be used as a dosimeter at low radiation dose in the clinical radiotherapy

Finite Element Modelling of Creep Rupture on Grade 91 Steel using Monkman-Grant Ductility based Damage Model

Failure strain is a main parameter used in the ductility exhaustion based damage model in which the accuracy of the prediction is dependent on its input value. The experimental measured has indicated that the value of strain at fracture is extensively scattered, therefore may affect the prediction. This paper presents the result of creep rupture time using a modified creep damage model incorporating Monkman-Grant (MG) failure strain as an alternative to strain at fracture. Both strains at fracture and MG failure strain are separately employed in the damage model to predict the failure time of uniaxial smooth specimen and notched bar with different acuity ratios of 3.0 and 20. The FE model of the specimen is loaded under different stress values and the multiaxial failure strain at each stress level is estimated using Cock and Ashby void growth model. The predicted creep rupture time that is compared to the experimental data (in a range of 40-1000 hours) showing a good agreement within the scatter band of +/- factor of 2. Both approaches using strain at fracture and MG failure strain can be used in predicting the creep failure under uniaxial and multiaxial features. The advantage of using MG strain is that the laboratory creep testing can be interrupted prior to specimen fractured or once the secondary creep deformation occurs. Meanwhile, the determination of strain at fracture needs longer test duration where the test can be stopped only when the specimen broken

Mechanical and thermal properties of sugar palm fiber reinforced thermoplastic polyurethane composites: effect of silane treatment and fiber loading

The aim of the present study was to develop sugar palm fiber (SPF) reinforced thermoplastic polyurethane (TPU) composites and to investigate the effects of fiber surface modification by 2% silane treatment and fiber loading (0, 10, 20, 30, 40 and 50 wt%) on the mechanical and thermal properties of the obtained composites. Surface treatment was employed to improve the fiber-matrix interface, which was expected to boost the mechanical strength of the composites, in terms of tensile, flexural and impact properties. Thermal properties were also investigated by thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) to assess the thermal stability of the developed composites. Furthermore, scanning electron microscopy (SEM) was used to study the tensile fracture samples of composites with a view towards evaluating the effects of fiber surface treatments on the fiber/matrix interfacial bonding. The findings of this study reveal that the silane treatment has determined good bonding and linkage of the cellulose fiber to the TPU matrix, hence contributing to enhanced mechanical and thermal properties of the composites. The composite formulation with 40 wt% sugar palm fiber loading showed optimum values such as 17.22 MPa for tensile, 13.96 MPa for flexural, and 15.47 kJ/m2 for impact strength. Moreover, the formulations with higher fiber content exhibited satisfactory values of storage modulus and thermal degradation, while their good interfacial adhesion was evidenced by SEM images

Aplikasi Toefl Preparation Berbasis Ibt (Internet Based Test)

Perkembangan  teknologi  internet  sangat  pesat  terutama  web.  Selain  berfungsi  sebagai  media  informasi, web  juga  dapat  dijadikan  sebagai  media  pembelajaran  misalnya  pembelajaran Test  Of  English  as  Foreign Language (TOEFL). Tes tersebut merupakan sebuah tes yang mengukur kemampuan bahasa Inggris seseorang. Pada aplikasi ini digunakan jenis TOEFL iBT yaitu TOEFL yang berbasis internet. Tes tersebut terdiri dari empat sesi yaitu Listening, Writing, Reading, dan Speaking. Jenis ujian pun dibagi menjadi dua bagian yaitu Individual Test dan Integrated Test. Aplikasi ini menyediakan sebuah simulasi tes TOEFL iBT layaknya seperti tes yang akan  dihadapi  dan dapat  membantu  para  mahasiswa  untuk  melakukan  persiapan  ujian TOEFL  iBT dengan mengerjakan soal-soal yang ada pada aplikasi secara mandiri

Perceived Social Support and Depression Level Among Elderly Living in Institution

The Elderly is commonly withdrawn and live alone due to a lack of social support, which impacts psychological issues. This study was conducted to identify the relationship between perceived social support and the level of depression among the elderly. This cross-sectional study enrolled 92 older people who lived at Rumah Seri Kenangan Cheng, Malacca. They completed the Multidimensional Scale for Perceived Social Support and Geriatric Depression Scale, which measured levels of social support and levels of depression, respectively. Findings indicated the elderly received moderate social support from family and friends, that affecting the level of depression in the elderly population. Keywords: Elderly, institutionalization, social support, depression. eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v7i20.344

Production, Processes and Modification of Nanocrystalline Cellulose from Agro-Waste: A Review

Nanocrystalline cellulose is a renewable nanomaterial that has gained huge attention for its use in various applications from advanced biomedical material to food packaging material due to its exceptional physical and biological properties, such as high crystallinity degree, large specific surface area, high aspect ratio, high thermal resistance, good mechanical properties, abundance of surface hydroxyl groups, low toxicity, biodegradability, and biocompatibility. However, they still have drawbacks: (1) sources of raw materials and its utilization in the production of nanocomposites and (2) high chemical and energy consumption regarding the isolation of macro-sized fibers to nano-sized fibers. The incorporation of hydrophilic nanocrystalline cellulose within hydrophobic polymer limits the dispersion of nano-sized fibers, thus resulting in low mechanical properties of nanocomposites. Hence, surface modification on nano-sized fiber could be a solution to this problem. This review focuses on the advanced developments in pretreatment, nanocrystalline production and modifications, and its application in food packaging, biomedical materials, pharmaceutical, substitution biomaterials, drug excipient, drug delivery automotive, and nanopaper applications