38 research outputs found
Pengaruh Variasi Media Pendingin Proses Quenching Terhadap Mikrostruktur dan Sifat Mekanik Baja Hadfield
No full textManganese steel contains 1,2% C and 12% Mn generally recognized as Hadfield steel. Based on the high composition of C and Mn elements, the main structure of this steel is dominated by an austenite matrix that surrounded the carbide phase on the grain boundary. This structure is usually brittle which leads to improper high-loading conditions. To overcome this problem, the experimental method was carried out by heating Hadfield steel to a temperature of 1000 oC, then followed by a quenching process using cooling media variations namely water and salt bath (20 wt.% NaCl solution). These cooling media variations aim to determine the level of carbide formation which affects the microstructure and mechanical properties. From the test results, it was obtained that Hadfield steel with salt bath (20 wt.% NaCl) quenching variation has significant microstructure transformation which affects enhancement of the value of tensile and yield strength (809,5 and 542,4 MPa), hardness (238 HV), ductility and toughness.Baja mangan yang mengandung 1,2% C dan 12% Mn dikenal secara umum sebagai baja Hadfield. Berdasarkan tingginya kandungan unsur C dan Mn, struktur utama baja ini didominasi oleh matriks austenit yang dikelilingi fasa karbida pada batas butirnya. Struktur tersebut biasanya rapuh dan cenderung tidak layak untuk penggunaan dalam kondisi pembebanan tinggi. Untuk mengatasi permasalahan tersebut, metode eksperimen dilakukan dengan cara memanaskan baja Hadfield hingga temperatur 1000 °C, kemudian dilanjutkan dengan proses quenching menggunakan variasi media pendingin yaitu air dan air garam 20 wt.% NaCl. Pemilihan variasi media pendingin ini bertujuan untuk mengetahui tingkat pembentukan fasa karbida dan pengaruhnya terhadap mikrostruktur dan sifat mekaniknya. Dari hasil pengujian didapatkan bahwa baja Hadfield dengan variasi quenching air garam 20 wt.% NaCl memiliki transformasi mikrostruktur yang signifikan sehingga berefek pada peningkatan nilai kekuatan tarik dan luluh (809,5 dan 542,4 MPa), kekerasan (238 HV), keuletan dan ketangguhannya
Pengaruh kosentrasi polivinil alkohol (PVA) terhadap performa elektrokima LiTi2 (PO4)3 hasil proses sol-gel sebagai anoda untuk baterai ion lithium tipe aqueous elektrolit
No full textPenelitian tentang baterai ion lithium sebagai sistem penyimpanan energi berkembang begitu pesat. Pada baterai ion lithium, salah satu bagian utama adalah anoda yang terdiri atas material LiTi2(PO4)3. Maka, penelitian ini bertujuan untuk mengetahui pengaruh konsentarsi polivinil alkohol (PVA) terhadap performa elektrokimia LiTi2(PO4)3 sebagai anoda baterai ion lithium. Proses sintesis material LiTi2(PO4)3 dilakukan dengan proses sol-gel menggunakan Li2CO3, TiO2, NH4H2PO4, dan variasi penambahan konsentrasi 5 wt%, 10 wt%, 15 wt% polivinil alkohol (PVA). Pada pengujian XRD dari ketiga sampel, teridentifikasi LiTi2(PO4)3 sesuai dengan JCPDS 35-074 meskipun masih ada fasa lain dalam intensitas yang kecil. Pengujian SEM menunjukkan bahwa material LiTi2(PO4)3 5wt.% PVA memiliki ukuran partikel yang lebih kecil dibandingkan dengan lainnya. Namun demikian, ukuran partikel tidak merata dan masih ada sedikit aglomerasi karena proses kalsinasi pada temperatur tinggi. Pengujian performa elektrokimia Cyclic Voltammetry (CV) menunjukkan bahwa anoda LiTi2(PO4)3 5wt.% PVA menunjukkan nilai kinetik ion yang tinggi, karena pada anoda tersebut memiliki ukuran partikel yang paling kecil dibandingkan yang lainnya sehingga meningkatkan difusivitas ion Li+. Adapun pengujian Galvanostat Charge-Discharge menunjukkan bahwa anoda LiTi2(PO4)3 5wt.% PVA memiliki stabilitas yang lebih baik karena pada anoda LiTi2(PO4)3 5wt.% PVA memiliki sebaran ukuran partikel yang lebih kecil sehingga transfer ion saat proses interkalasi/de-interkalasi dapat berlangsung secara stabil.
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The development of research on lithium ion battery as energy storage system is very rapidly. In lithium ion battery, one of the main part composed as anode by the material LiTi2(PO4)3. So, this research aimed to determine the effect of the concentration of polyvinyl alcohol (PVA) on the electrochemical performance LiTi2(PO4)3 as an anode of lithium ion battery. The synthesis process of LiTi2(PO4)3 conducted by sol-gel process that using Li2CO3, TiO2, NH4H2PO4, and variations in concentrations of 5 wt%, 10 wt%, 15 wt% polyvinyl alcohol (PVA). In the XRD testing of three samples, identified LiTi2(PO4)3 according to JCPDF 35-074 although there is still other phase in a small intensity. The SEM test showed the material LiTi2(PO4)3 5wt.% PVA have particles size smaller than the other variations. However, the particle size is not homogeny and there is still little agglomeration due to the calcination process at high temperature. The electrochemical performance test of Cyclic Voltammetry (CV) showed that anode LiTi2(PO4)3 5wt.% PVA showed high ion kinetic values, because at the anode has the smallest particle size compared to the other, increasing the Li+ ion diffusivity. The Charge-Discharge Galvanostat testing showed that the anode LiTi2(PO4)3 5wt.% PVA has better stability because the anode LiTi2(PO4)3 5wt.% PVA has a particle size distribution smaller, so that the transfer of ions during the process of intercalation/de-intercalation can take place in a stable
KONSTRUKSI HUBUNGAN HUKUM PARA PIHAK DALAM PERJANJIAN KERJA SAMA SEBAGAI WUJUD PERLINDUNGAN BAGI PEKERJA (Studi Kasus Perjanjian Kerja Sama Mudharabah Go Fish Tuban PT Indonesia Berkah Mandiri No:005/IBM/PKS/V/2019 dengan Ir. Sardjono Santoso)
No full textMohamad Azmy, Ratih Dheviana Puru HT., Budi SantosoFakultas Hukum, Universitas Brawijaya MalangEmail: [email protected] Indonesia sedang berkembang inovasi perjanjian kerja sama yaitu waralaba / franchise. Salah satu waralaba yang baru didirikan dan mulai berkembang di beberapa kota adalah PT Indonesia Berkah Mandiri dengan brand Go Fish. Go Fish merupakan sebuah restoran cepat saji. Terkait dengan pekerja yang menjadi pihak dalam penyelenggaraan waralaba, selain pemberi waralaba dan penerima waralaba, maka penting untuk mendapat perlindungan hukum sebagai hak pekerja yang harus diberikan kepada pekerja. Sebagai waralaba baru yang berkembang, penyusunan perjanjian menarik untuk dikaji lebih dalam, khususnya terkait dengan konstruksi hubungan hukum para pihak dalam perjanjian tersebut sebagai wujud perlindungan bagi pekerja. Didalam perjanjian tersebut menggunakan frasa yang tidak sesuai dengan tujuan dan maksud seperti “Investasi atau Penanaman Modalâ€, sehingga menimbulkan ketidakjelasan bagi para pekerja untuk mendapatkan hak – haknya. Penulis menggunakan metode penelitian hukum normatif dengan menggunakan pendekatan perundang-undangan (statue approach) dan pendekatan konsep (conseptual approach ). Berdasarkan hasil penelitian dapat disimpulkan bahwa perjanjian kerja sama tersebut dikualifikasikan sebagai perjanjian waralaba / franchise sebab adanya kesesuaian antara karakteristik waralaba dengan isi perjanjian Go Fish. Berkaitan dengan wujud perlindungan bagi pekerja, di dalam perjanjian Go Fish tidak menyebutkan tentang hak perlindungan bagi pekerja yang ikut dalam penyelenggaraan kerja sama waralaba sehingga dapat disimpulkan lemahnya dalam memberikan perlindungan hukum bagi pekerja.Kata Kunci : Konstruksi Hubungan Hukum, Perjanjian Kerja Sama, Perlindungan Hukum ABSTRACT Cooperation agreement in franchise is growing in Indonesia. PT Indonesia Berkah Mandiri with Go Fish brand, a fast food restaurant, is one of franchises that can be found in Indonesia. In addition to protection provided for both franchisors and franchisees, the staff working in franchise companies also deserve protection for their rights as workers. As a new developing franchise, the company holds an agreement that attracts the author to look deeper into it, especially regarding construction of legal connection among parties involved in the agreement as part of protection provision for employees. The agreement used a phrase irrelevant to the objective and intention of the company “investment and capital investmentâ€. This phrase has sparked ambiguity for employees in terms of obtaining their rights. This research employed grammatical interpretation to seek into the agreement further. The research learns that the agreement made is categorised as franchise agreement because it met what is required in the Government Regulation Number 42 of 2007 concerning Franchise. Several Articles also imply that the employees work for PT. Indonesia Berkah Mandiri, and thus regulation concerning social security for workers in franchise companies is also required.  Keywords: agreement, franchise, capital investment, Mudharabah, social security Â
Construction of Hierarchical CuCo2O4-Ni(OH)2 Core-Shell Nanowire Arrays for High-Performance Pseudocapacitors
No full textThe hierarchical CuCo2O4-Ni(OH)2 core-shell nanowire arrays on Ni foam were fabricated using facile and cost-effective two-step hydrothermal synthesis. The growth of CuCo2O4 nanowires was developed on Ni foam as the apposite basis of the conductive scaffold, and the ultrathin Ni(OH)2 nanowires were subsequently immobilized to form CuCo2O4-Ni(OH)2 core-shell nanowire arrays (NWAs). The prepared materials were further characterized in structural, morphological, and electrochemical properties. The obtained CuCo2O4-Ni(OH)2 pseudocapacitor electrode, incorporated by unique core-shell heterostructures nanowire arrays, exhibited great specific capacitance of 1201.67 F g-1 at 1 mA g-1, which is much higher than pristine CuCo2O4 nanowire of 638.89 F g-1 at 1 mA g-1 . Simultaneously, it also has a high power density of 5.56 kW kg-1 at an energy density of 73.33 Wh kg-1 and good long-term cycling performance (~84 capacitance retention after 1000 cycles). The improved morphological and structural properties have substantiated the CuCo2O4- Ni(OH)2 core-shell nanowire arrays properties owing to higher surface active area and richer redox activity for boosting the electrochemical properties
Pengaruh Konsentrasi Polivinil Alkohol (PVA) Terhadap Performa Elektrokimia LiTi2(PO4)3 Hasil Proses Sol-Gel Sebagai Anoda Untuk Baterai Ion Lithium Tipe Aqueous Elektrolit
No full textPenelitian tentang baterai ion lithium sebagai sistem penyimpanan energi berkembang begitu pesat. Pada baterai ion lithium, salah satu bagian utama adalah anoda yang terdiri atas material LiTi2(PO4)3. Maka, penelitian ini bertujuan untuk mengetahui pengaruh konsentarsi polivinil alkohol (PVA) terhadap performa elektrokimia LiTi2(PO4)3 sebagai anoda baterai ion lithium. Proses sintesis material LiTi2(PO4)3 dilakukan dengan proses sol-gel menggunakan Li2CO3, TiO2, NH4H2PO4, dan variasi penambahan konsentrasi 5 wt%, 10 wt%, 15 wt% polivinil alkohol (PVA). Pada pengujian XRD dari ketiga sampel, teridentifikasi LiTi2(PO4)3 sesuai dengan JCPDS 35-074 meskipun masih ada fasa lain dalam intensitas yang kecil. Pengujian SEM menunjukkan bahwa material LiTi2(PO4)3 5wt% PVA memiliki ukuran partikel yang lebih kecil dibandingkan dengan lainnya. Namun demikian, ukuran partikel tidak merata dan masih ada sedikit aglomerasi karena proses kalsinasi pada temperatur tinggi. Pengujian performa elektrokimia Cyclic Voltammetry (CV) menunjukkan bahwa anoda LiTi2(PO4)3 5wt% PVA menunjukkan nilai kinetik ion yang tinggi, karena pada anoda tersebut memiliki ukuran partikel yang paling kecil dibandingkan yang lainnya sehingga meningkatkan difusivitas ion Li+. Adapun pengujian Galvanostat Charge-Discharge menunjukkan bahwa anoda LiTi2(PO4)3 5wt% PVA memiliki stabilitas yang lebih baik karena pada anoda LiTi2(PO4)3 5wt% PVA memiliki sebaran ukuran partikel yang lebih kecil sehingga transfer ion saat proses interkalasi/de-interkalasi dapat berlangsung secara stabil
Monolithically integrated microelectromechanical systems resonators and oscillators in standard IC technology
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 239-255).Frequency sources and high quality filters based on mechanical resonators are essential building blocks for communication systems as well as analog and digital electronics. Driven by the continuous demand for reduction in power, size and overall cost, monolithic integration of mechanical resonators in standard integrated circuit (IC) technology has been the focus of multiple research efforts. Micro-Electro-Mechanical (MEM) resonators offer an ultimate solution, with 100x higher quality factors and 10⁴x smaller footprint, when compared to on-chip LC tank circuits. A new class of truly solid-state, monolithically integrated, GHz-frequencies CMOS-MEMS resonators is presented. No post-processing or special packaging of any kind is required beyond the standard CMOS process. Resonant body transistor (RBT) is constructed by using active field-effect-transistor (FET) sensing. A phononic crystal (PnC) implemented in the CMOS back-end-of-line (BEOL) layers along with the bulk wafer are used to create a phononic waveguide. The latter confines acoustic vibrations in the CMOS front-end-of-line (FEOL) layers. Operator-theoretic analysis for these waveguides is presented in explicit analogy to quantum mechanics and photonic waveguides; with a study of perturbation theory, coupled-mode theory and adiabatic theorem. Superior energy confinement is achieved, allowing record high Q ~ 14, 800 and fo - Q ~ 4.85 x 10¹³ for CMOS-RBTs at 3 GHz. Simulation, modeling, optimization, proto- typing and testing of these resonators is presented. RBTs in FinFET technologies are also exploerd, for resonance frequencies up to 33 GHz. The thesis also explores the integration of Lamb-mode resonators in standard GaN monolithic-microwave-IC (MMIC) process. The first monolithic 1GHz MEMS-based oscillator in standard GaN MMIC technology is demonstrated, together with monolithic lattice and ladder filters. This allows for complete RF front-ends in GaN MMIC technology.by Bichoy Waguih Azmy Bahr.Ph. D
Investigasi Sifat Mekanik terhadap Perbedaan Media Pendingin pada Proses Induction Hardening Baja AISI 1015
No full textAISI 1015 steels have been vigorously used to numerous automotive parts. Unfortunately, it has several mechanical shortcomings due to poor hardness, wear resistance, and strength. To tackle its crucial problem, the AISI 1015 steels have been treated by induction hardening treatment at 850 oC which subsequently cooling to the ambient temperature using different cooling media of water, salt bath, and oil. The as-prepared AISI 1015 steels were then investigated its mechanical properties involving spectrometry, microstructure observation, hardness, wear, and tensile test. The AISI 1015 treated steels after induction hardening in water cooling media exhibited intriguing microstructure of vast pearlite encircle ferrite matrix. The sample also garnered significant enhancements of hardness, wear resistance, and tensile properties. These superior mechanical characteristics are believed to be catered for the induction treatment using water cooling media which boost crystalline structure transformation deliberately. Therefore, this research affords significant promise for improved mechanical properties of the AISI 1015 steels
Quality Estimation for Scarce Scenarios within Mobile Crowdsensing Systems
No full textMobile crowdsensing (MCS) is a paradigm that exploits the presence of a crowd of moving human participants to acquire, or generate, data from their environment. As a part of the Internet-of-Things (IoT) paradigm, MCS serves the quest for a more efficient operation of a smart city. Big data techniques employed on this data produce inferences about the participants' environment, the smart city. However, sufficient amounts of data are not always available. Sometimes, the available data are scarce as it is obtained at different times, locations, and from different MCS participants who may not be present. As a consequence, the scale of data acquired may be small and susceptible to errors. In such scenarios, the MCS system requires techniques that acquire reliable inferences from such limited data sets. To that end, we resort to small data (SD) techniques that are relevant for scarce and erroneous scenarios. In this article, we discuss SD and propose schemes to tackle the problems associated with such limited data sets, in the context of the smart city. We propose two novel quality metrics: 1) MAD quality metric (MAD-Q) and 2) MAD bootstrap quality metric (MADBS-Q), to deal with SD, focusing on evaluating the quality of a data set within MCS. We also propose an MCS-specific coverage metric that combines the spatial dimension with MAD-Q and MADBS-Q. We show the performance of all the presented techniques through closed-form mathematical expressions, with which simulation results were found to be consistent.Manuscript received January 10, 2020; revised April 11, 2020; accepted April 27, 2020. Date of publication May 14, 2020; date of current version November 12, 2020. This work was supported by the Natural Sciences and Engineering Research Council of Canada under Grant RGPIN-2019-05667.(Corresponding author: Nizar Zorba.) Sherif B. Azmy is with the Department of Electrical and Computer Engineering, Queen's University, Kingston, ON K7L 3N6, Canada (e-mail: [email protected]).Scopu
Perancangan Alat Peniris Minyak Pada Makanan Dengan Pengatur Putaran Kapasitas 2 Kg
No full textMinyak goreng merupakan salah satu kebutuhan pokok dalam proses memasak untuk menunjang kebutuhan sehari-hari. Proses penggunaan minyak goreng biasanya dilakukan secara berulang sehingga masih menyisakan suatu permasalahan dalam proses penirisannya. Untuk mengatasi masalah tersebut, maka diperlukan alat peniris minyak pada makanan (spinner) agar proses penirisan minyaknya dapat berjalan optimal. Alat peniris minyak pada makanan (spinner) ini dapat digunakan untuk meniriskan makanan sejenis keripik, kerupuk, makaroni, bawang goreng, dan sejenisnya. Adapun perancangan alat peniris minyak pada makanan ini dilakukan dalam beberapa tahapan yaitu tahap mengidentifikasi masalah dengan metode studi literatur, tahap pembuatan konsep dan cara kerja alat, tahap perhitungan, tahap pemilihan komponen sesuai dengan hasil perhitungan, dan tahap mendesain alat dan membuat gambar kerjanya. Berdasarkan hasil perancangan yang telah dilakukan, maka dihasilkan sebuah rancangan alat peniris minyak pada makanan (spinner) dengan spesifikasi dimensi rangka 560x300x300 mm. Motor penggerak yang digunakan adalah motor AC 4P/1200 rpm dengan sistem transmisi berupa puli dan sabuk V, serta poros transmisi yang berfungsi untuk menggerakkan tabung peniris. Alat peniris minyak pada makanan (spinner) ini dirancang memiliki kapasitas 2 kg, dengan dilengkapi pengatur putaran yang memiliki kecepatan maksimum 500 rpm dan kecepatan minimum ±200 rpm, sehingga putaran tabung peniris dapat disesuaikan dengan kebutuhan
Effect of Welding Speed on Residual Stress and Distortion of AISI 1045 Plate Using the Finite Element Method (FEM)
No full textWelding is one of the metals joining methods to assembly parts which are used in manufacturing, automotive, and aerospace industries. The welding process merely simulated in modelling using finite element method (FEM). Simulation is used to determine how the effect of welding speed on the distribution of temperature, residual stress, and deformation in the V-Butt Joint welding model. The material used in this welding simulation is AISI 1045 plate with a thickness of 8 mm. Variable speed of welding performed in 30 cm/minute, 40 cm/minute and 50 cm/minute. As the result, the residual stress and distortion will be compared in order to find the best welding speed which produces the smallest residual stress and distortion value. Welding simulation based on SMAW with 6.3 mm of E7016 electrode, current of 150 A, voltage of 26 V, and single-pass welding. The finite element method using the ANSYS 2020 R2 software for simulation. Welding simulation uses transient thermal and moving heat flux features, while residual stresses and distortion use static structural features. From this research, the maximum temperature distribution after welding at welding speeds of 30 cm/minute, 40 cm/minute and 50 cm/minute were 295.22 ℃, 240.59 ℃ and 205.94 ℃, respectively. In this study, the welding speed of 30cm/minute has the highest values of residual stress and distortion, which is about 0.00000036965 MPa and 0.090894 mm. Besides, for welding speed of 40 cm/minute and 50 cm/minute, the total residual stress and total distortion value are 0.00000027744 MPa; 0.067248 mm and 0.00000022218 MPa; 0.053419 mm, respectively
