Development of a Noise Filtering Algorithm for Strain Signals Using the Fast Fourier Transform

The purpose of this study is to filter the noise in strain signals based on the fast Fourier transform. The strain signals were measured at an automotive lower arm made from the SAE 1045 carbon steel driven on paving block and asphalt. This technique removed lower amplitude cycles as much as possible due to their contribution to the minimum fatigue damage and simultaneous maintenance of cumulative fatigue damage. The filtering algorithm was able to remove up to 36.2 % of the lower amplitude cycles and maintain more than 90 % of the fatigue damage. This proved that the algorithm developed was successfully identified and eliminated low amplitude cycles

SISTEM INFORMASI LOKASI KOS-KOSAN DI KOTA LHOKSEUMAWE BERBASIS ANDROID

Kos merupakan jasa yang menawarkan sebuah kamar atau tempat untuk ditinggali dengan sejumlah pembayaran tertentu untuk setiap periode tertentu. Untuk mendapatkan sebuah kos dengan lokasi dan tingkat kelayakan serta kesesuaian dengan dana yang tersedia bagi seorang mahasiswa atau masyarakat umum yang baru tiba di Lhokseumawe, bukanlah sesuatu yang mudah sehingga mahasiswa atau masyarakat umum tersebut dituntut berusaha keras mencari dan menanyakan informasi kos secara manual yang pada akhir menyita waktu, tenaga dan dana. Untuk itu dilakukan pembuatan aplikasi pencarian kos di Lhokseumawe, sehingga pencarian kos dapat dilakukan dalam waktu yang cepat dan murah serta sesuai dengan keinginan. Sistem ini dibangun berbasis adroid sehingga fleksibel dalam pengguannya dan menggunakan metode selection sort, untuk mengurutkan harga kos dari yang termurah hingga termahal atau sebaliknya. Untuk penunjukan lokasi, aplikasi ini  memanfaatkan fasilitas yang ada pada Google API

Effect of temperature on the mechanical performance of highly conductive composites for HT-PEMFC application

This study is a follow-up study of a previous study that examined the effect of temperature on the mechanical performance of the polymer carbon composite (CCP). In this study, the optimal formulation obtained from previous studies, was tried for use in polymer fuel cells of high temperature polymer electrolytes. The standard used is, the standard for bending strength specified by the US Department of Energy (DOE) Agency, which has determined the bending strength should be higher than 25 a. Preparation of CCP bipolar plates is done by internal mixing and then molded by compression stirring method. Bending strength and hardness test are carried out at 26°C to 200°C, for 80% CNT/NG mixture and 20% by weight of EP, with a resin/hardener ratio of 3: 1. This composition has successfully met the bending strength standards set by the DOE on testing performed at room temperature. However, the composite electrical conductivity is still less than the standard set by DOE, reaching only 50 S/cm. The results show that the composite plate of CNT/NG/EP mixed with a 5/75/20% by weight composition is not suitable for HT-PEMFC, because the filler and matrix composite interface failed to hold the bonds at temperature higher than the melting point of the EP. It is therefore recommended that this composite material be used only at low temperatures and is also not recommended for use as a fuel cell plate

Finite Element Analysis for Stress Distribution in a Proton Exchange Membrane Fuel Cell Stack

The component design of a proton exchange membrane fuel cell (PEMFC) considerably affects pressure distribution in the PEMFC stack by creating uniform and effective pressure distribution. Assembly and component designs are essential in the PEMFC system to achieve optimal performance and durability of the PEMFC stack. Inadequate pressure in the stacking process can damage the cells and cause leakage and contact resistance. Moreover, an uneven distribution of pressure produces hot spots that can damage the system. Achieving the optimal design with reduced production cost requires pressure distribution simulation during the assembly. Finite element analysis (FEA) was used to analyze system behavior with pressure variation during assembly by using Autodesk Inventory software. This study discussed the geometric modeling and FEA of the tensile distribution of the PEMFC stack. The detailed components reported on the geometry, dimensions, and mechanical properties of PEMFC components, such as membranes, gas diffusion layers, end plates, and bipolar plates. Results from the simulations showed no significant difference in the deformation of cells in the PEMFC stack, with changes in tensile distribution

Kesan pemendapan elektroforesis gam arab terhadap kakisan SS316 L dalam persekitaran asid

Keluli tahan karat jenis 316L (SS316L) adalah satu logam yang berpotensi untuk digunakan sebagai plat dwikutub bagi sel fuel membran pertukaran proton (PEMFC). SS316L memiliki sifat kekonduksian elektrik dan kepasifan yang baik, namun jika digunakan pada sekitaran asid (pH 3-6), sifat pelarutan SS316L akan menyebabkan mudah terhakis. Dalam kajian ini, salutan perencat kakisan hijau gam arab dengan kaedah pemendapan elektroforesis (EPD) digunakan untuk mengurangkan kakisan plat SS316L. Hasil analisis scaning electron microscope (SEM) menunjukkan permukaan SS316L lebih halus dan tebal, dengan ketebalan salutan antara 4.9 - 8.9 μm. Pengujian menggunakan kaedah polarisasi linear Tafel dalam media 0.5 M H2 SO4 , mendapati nilai arus kakisan (Icorr) semakin menurun dengan adanya salutan iaitu dari 18.484 μA/cm2 menjadi 0.859 μA/cm2 . Kadar kakisan SS316L tanpa salutan adalah 0.7172 mpy, manakala SS316L yang disalut dengan gam arab mempunyai kadar kakisan yang lebih rendah iaitu 0.033 mpy. Dari kajian ini, keputusan menunjukkan bahawa gam arab dengan salutan EPD dapat memberikan perlindungan kakisan terhadap permukaan SS316L

Static stress analysis of membrane electrode assembly (MEA) and gasket in Proton exchange membrane fuel cell stack assembly pressure

The proton exchange membrane fuel cell (PEMFC) system was an electrochemical device that generates electricity through the reaction of hydrogen and oxygen without combustion. Proton Exchange Membrane (PEM) stacks typically consisted of components combined into one unit and equipped with suitable clamping torque. This was to prevent reactant gas leakage and minimize the contact resistance between the gas diffusion medium and the bipolar plate. The combined components consisted of a bipolar plate with a flow field, current collector, membrane electrode assembly (MEA), endplate, and gasket. PEMFC performance was measured concerning its power output, which depends on temperature and the operating pressure. Various efforts had been made to determine the optimal compaction pressure and its distribution through simulations and experiments. Therefore, this research analyzed the static stress of membrane electrode assembly (MEA) and gasket in PEMFC stack assembly pressure. The components’ geometric dimensions and mechanical properties, such as endplates, current collectors, bipolar plates, MEAs, and gaskets, were combined for electricity. Pressure-sensitive film (Fuji measure film prescale) was also used to visualize contact pressure distribution between the MEA and the bipolar plate. The result showed that the color variation of the pressure film indicates the exact distribution of pressure entering the stacking design and the contact image. In conclusion, the detailed contact pressure distribution was an important influence on heat transfer processes and local electrochemical reactions in cell stacks

Inter-Ethnics Relationship Speech in Indonesian High School History

This study aims to examine the role of history education in managing the diversity of Indonesian society, ethnicity, religion, customs and language. The study analyzed the newest edition of Indonesian official textbooks for the high school history lessons. The analysis was conducted using the Critical Discourse Analysis (CDA). The results showed that history textbooks in Indonesia made a minimal contribution to managing diversity. Historical textbooks are ignoring the existence of thousands of ethnic groups in Indonesia. As a result, students feel that the history of Indonesia contained in textbooks is not their past, and at the next level, they live without history.Este estudio tiene como objetivo examinar el papel de la educación en historia en la gestión de la diversidad de la sociedad, el idioma y la religión de Indonesia. El estudio analizó la edición más reciente de los libros de texto oficiales de Indonesia para la lección de historia de la escuela secundaria. El análisis se realizó utilizando el Análisis Crítico del Discurso (CDA). Los resultados mostraron que los libros de texto de historia en Indonesia hicieron una contribución mínima a la gestión de la diversidad. Los estudiantes sienten que la historia de Indonesia contenida en los libros de texto no es su pasado y, en el siguiente nivel, viven sin historia

Effects of the synthesis coating parameters for metal bipolar plates

Metallic bipolar plates tendency to have high contact resistance, but also very susceptible to corrosion. This may decrease in the performance of fuel cells after several times of usage in fuel cell applications. Research has shown that after a metal plate was coated, the characteristic of materials dependent on the type, composition of the coating materials and the method. This study determines design of coating parameters including gas flow rate, DC power, and deposition time of coating for metal bipolar plates, which can be an indicator of the suitability of these plates for use as bipolar plates in proton exchange membrane fuel cell (PEMFC) applications. The aim of this research was to obtain a limitation range value of parameters that can be used as a standard for the use of metal plates as bipolar plates. The optimization parameters designed by Taguchi are used to determine the characteristics of interfacial contact resistance (ICR) and corrosion current density (Icorr). The integration of the Taguchi method with simulation can show the optimal design parameters of the coating on the various materials use. The optimization feature based on Taguchi is applied to ICR and Icorr values, to determine the feasibility of metal plates as potential bipolar plates in PEMFC

Single stack performance using chromium carbide (Cr‒C) and niobium carbide (Nb‒C) coated on 316 L bipolar plates

Metallic bipolar plates tendency to have high contact resistance and corrosion after several times of usage affected performance of a cell in PEMFC stack. Thisstudy focused on the interfacial contactresistance (ICR) and corrosion resistance of SUS 316 L bipolar plates using Cr‒C and Nb‒C as coating layer, single stack performance in PEMFC were observed by experimental. The Cr‒C and Nb‒C coating layer acted as protective layer between SUS 316 L bipolar plates. Therefore, coating is a method in preventing the bipolar plates surface material from damage in the acidic environment of PEMFC. To develop corrosion-resistant and high conductivity bipolar plates for PEMFC, the coatings bipolar plates were applied to cell fabrication in comparison with bare SUS 316 L bipolar plates. The SUS 316 L bipolar plates size and electrode area were 50 mm2 and 25 mm2 , respectively. The experiment was carried out on a prepared assembled single cell bipolar plates with the commercial membranes, conductive carbon papers and gasket. Initial performance of the single cells using Cr‒C and Nb‒C coatings over SUS 316 L bipolar plates were recorded at a cell voltage between 0.4 V to 0.5 V, respectively. In comparison, Nb‒C gives good performance of corrosion resistance and the ICR value as low as 10‒12 A/cm2 and 1.22 mΩ cm−2. Additionally, it gives maximum power density of 137 mW/cm2 at the cell voltage 0.51 V. The lifetime durability of the single cell significantly improved from the uncoated current density of 390 mA/cm2 to 450 mA/cm2 with Nb‒C coating layer