Khairurrijal Khairurrijal
Kelompok Keilmuan Fisika Material Elektronik, Fakultas Matematika dan Ilmu Pengetahuan Alam, Institut Teknologi Bandung

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Sifat Listrik Film Tipis SrTiO3 untuk Kapasitor MOS Darsikin Darsikin; Khairurrijal Khairurrijal; Sukirno Sukirno; Mohamad Barmawi
Jurnal Matematika & Sains Vol 10, No 3 (2005)
Publisher : Institut Teknologi Bandung

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Abstract

Strontium titanate (SrTiO3) film was successfully deposited on a silicon substrate by using a pulsed-laser ablation deposition (PLAD) technique. The optimum temperature is 600o C. The electrical properties measurement was metal-oxide-semiconductor capacitor. The film exhibits good insulating property at room temperature. The fixed charge density and leakage current density were also calculated. The results show that the films have promising applications as alternative gate dielectrics.
Kapasitor MOS dengan dielektrik Ceria Amorf Khairurrijal Khairurrijal; Darsikin Darsikin; Maman Budiman
Jurnal Matematika & Sains Vol 9, No 3 (2004)
Publisher : Institut Teknologi Bandung

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Abstract

Amorphous ceria (CeO2) thin films were deposited on a silicon (100) substrate by using a pulsed-laser ablation deposition (PLAD) technique. The substrate temperature was varied from 600 to 7000 C and the ambient was a pure oxygen gas at the pressure of 100 mTorr. It was found that the growth rate is 17.5 nm/min. Low fixed-charge densities (1011/cm2) and high resistivies (109-1012 Ω cm) of the CeO2 thin films indicate that the films could be used for oxide layer of metal-oxide-semiconductor (MOS) capacitors. Electron conduction mechanism in the CeO2 thin films is ohmic at voltages below 1 V while that at voltages above 1 V are due to quantum tunneling process.
Gelation Model for Porosity Dependent Fluid Permeability in Porous Materials Mikrajuddin Abdullah; Khairurrijal Khairurrijal
Jurnal Matematika & Sains Vol 14, No 1 (2009)
Publisher : Institut Teknologi Bandung

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Abstract

A statistical theory of gel formation in a polymer matrix was used to explain the dependence of liquid permeability in porous materials. A porous material was modeled as a dispersion of bubbles in a solid matrix. Bubbles were treated as monomers and formation of infinite connected bubbles was treated as the formation of gels in polymer. The theoretical predictions were in agreement with the observed data for basalt andesits. The model can easily predict the percolation threshold of porosity at which the permeability increases suddenly, which depends on the effective number of nearest bubbles around a selected bubble. Around the percolation threshold, the permeability satisfies a scaling relationship with a critical exponent of t » 1.2. It is also identified that the critical exponent and fractal dimension of pores, D, satisfy t » 0.8 (1 + 1/D).
Dinamika Paket Gelombang Elektron yang Menerobos Penghalang Trapesium dengan Ketebalan Nanometer Maharati Hamida; Khairurrijal Khairurrijal; Mikrajuddin Abdullah
Jurnal Matematika & Sains Vol 11, No 2 (2006)
Publisher : Institut Teknologi Bandung

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Abstract

A simulation of the dynamics of electrone wave packet tunneling through a potential barrier in a MOS (metal-oxide-semiconductor) diode was performed by solving the time-dependent Schrödinger equation using the finite difference method. The wave packet is initially located in the semiconductor layer then moves toward to the oxide layer and probably tunnels through and/or is reflected by the oxide layer. The wave packet is deformed when it reaches the oxide layer. It is found that the higher the wave packet energy, the faster the wave packet moves and the higher the probability of transmitting the wave packet for the same bias voltage. It was also found that at low energy, the increase of bias voltage does not increase significantly the probability of finding the transmitted wave packet. At high energy, however, the probability of finding the transmitted wave packet becomes higher with increasing the bias voltage.
A Simple Microcontroller-Based 4-20 mA Current Loop Receiver for Sensors with Current Transmitters Arif Surachman; A. Suhendi; Maman Budiman; Mikrajuddin Abdullah; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 2 No 1 (2010): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2010.2.1.2

Abstract

A current loop receiver system based on a microcontroller has been developed. The current loop receiver system can serve 8 gas sensors with 4-20 mA outputs, which are handled by employing a multiplexer. The data acquisition of the system is composed of a common operational amplifier-based current loop receiver, a CD4051 multiplexer, an ADS7822 serial analog to digital converter (ADC), and an AT89S52 microcontroller. The measured gas concentration is displayed on the 7-segments or transmitted to a personal computer via the RS232 serial communication to be processed by the Microsoft Excel. Additional functions such as gas concentration level warning and error code display are also provided. Keywords:4-20 mA, Current loop, Microcontroller, Receiver, Transmitter
Alat Ukur Curah Hujan Tipping-Bucket Sederhana dan Murah Berbasis Mikrokontroler Maria Evita; H Mahfudz; Suprijadi Suprijadi; Mitra Djamal; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 2 No 2 (2010): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2010.2.2.1

Abstract

Telah dirancang dan dibangun alat pengukur curah hujan tipe tipping-bucket (TB) berbasis mikrokontroler AT89S8252. Alat ini menghasilkan tetesan 0,21 mm untuk daerah tabung kecil terpancang sebagai penerima tetesan (tipping-bucket/TB) dari kerucut penampung air hujan seluas 2837,54 mm2. Untuk mencacah TB-nya, sensor tipe reed switch digunakan dan dibaca oleh data logger berbasis mikrokontroler AT89S8252. Data logger tersebut dilengkapi sebuah real time clock dan komunikasi serial agar dapat mengirimkan data ke komputer. Curah hujan maksimum yang bisa diukur adalah 914,4 mm/jam. Kata kunci: Curah hujan, sensor reed switch, mikrokontroler AT89S8252AbstractA Tipping-bucket (TB) rain gauge using AT89S8252 microcontroller has been designed and built. This device produces 0,21 mm drops of water for the small tube receiver (tipping bucket/TB) from the rain water cone area of 2837,54 mm2. Reed switch sensor is used for sampling TB and the sampling data will be read by data logger system using AT89S8252 microcontroller. Data logger system is provided with real time clock and communication serial for sending the data to the computer. Maximum rainfall that can be measured is 914.4 mm/hr. Keywords: Rainfall, reed switch sensor, microcontroller AT89S8252
Sistem Kontrol Otomatik Pembatasan Daya Listrik Berbasis Mikrokontroler PIC18F4520 Nur A. Aprianti; Indra W. Fathona; Suprijadi Suprijadi; Maman Budiman; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 2 No 2 (2010): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2010.2.2.6

Abstract

Sistem kontrol otomatik yang diterapkan untuk membatasi daya listrik telah dirancang dan dikembangkan berbasis mikrokontroler PIC18F4520. Dalam melakukan pengontrolan, sistem tersebut menggunakan aksi kontrol on-off. Sebagai aktuator digunakan Triac beserta drivernya sedangkan sensornya menggunakan sensor arus berbasis efek Hall. Sistem tersebut dilengkapi keypad untuk memasukkan set point arus dan peraga LCD untuk memantau arus yang terukur. Dari pengujian yang telah dilakukan, ditunjukkan bahwa sistem telah berjalan baik. Aksi kontrol PID (proporsional-integral-diferensial) disarankan menggantikan on-off untuk pengontrolan yang lebih baik. Kata kunci: Aksi kontrol on-off, Kontrol otomatik, Mikrokontroler PIC18F4520, Pembatas Daya, Sensor efek Hall, TriacAbstractAutomatic control system for controlling the electronic power has been designed and developed based on microcontroller PIC18F4520 and on-off control action. This system uses Triac and its driver as an actuator and Hall Effect-based current sensor. This system also provided with a keypad to enter the set point current and LCD display to monitor the flow measured. From the testing that has been conducted, it was showed that the system has been running well. PID (proportional-integral-differential) controller is suggested to replace the on-off controller for better controlling.  Keywords:  on-off control action, Automatic control, Microcontroller PIC18F4520, Power restrain, Hall Effect sensor, Triac
Klinostat Tiga Dimensi sebagai Simulator Mikrogravitasi untuk Berbagai Eksperimen Tanpa Bobot Indra W. Fathona; Arif Surachman; Ferry Iskandar; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 3 No 1 (2011): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2011.3.1.4

Abstract

Abstrak Sebuah klinostat tiga dimensi (3-D) telah dirancang untuk menyediakan sebuah lingkungan dengan gravitasi sangat kecil (mikrogravitasi) bagi berbagai percobaan tanpa bobot. Besarnya gravitasi berhubungan dengan kecepatan sudut dari perputaran klinostat tersebut. Dua buah rangka berbentuk segi empat diputar pada sumbu rotasi y-z dengan menggunakan dua motor DC dan kecepatannya diatur oleh mikrokontroler AT89S52 dengan menggunakan prinsip pulse width modulation (PWM). Alat ini telah diuji selama 8 jam tanpa henti untuk berbagai kecepatan sudut di bawah 17 rpm (rotation per minute). Telah didapatkan bahwa alat ini berfungsi dengan baik.Kata kunci: gaya sentrifugal, kecepatan sudut, klinostat, mikrogravitasi, rotasi.Abstract A three-dimensional (3-D) clinostat has been designed to provide an environment with very small gravity (microgravity) for weightless experiments. The obtained gravity is closely related to the angular speed of the clinostat rotation. Two rectangular frames are rotated by employing two DC motors around the y-z rotation axis and its angular speed is controlled by an AT89S52 microcontroller using the pulse width modulation (PWM) technique. Eight-hour continuous operations have been done for various angular speeds below 17 rpm. It has been found that the clinostat functions well.Keywords:angular velocity, centrifugal force, clinostat, microgravity, rotation.
Optimasi Parameter Pemintalan Elektrik Menggunakan Teknik Algoritma Genetika: Tegangan Listrik dan Jarak Nozzle-Kolektor S Saehana; Ferry Iskandar; Mikrajuddin Abdullah; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 3 No 1 (2011): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2011.3.1.5

Abstract

AbstrakStudi optimasi dua parameter pemintalan elektrik, yaitu tegangan listrik dan jarak nozzle-kolektor, telah dilakukan dengan teknik algoritma genetika dalam domain [1,60] kV dan [5,25] cm serta jumlah populasi 100 buah, peluang pindah silang (pc) 0,7 dan peluang mutasi (pm) 0,5. Jejari serat seukuran 155 nm diperoleh dari hasil subsitusi nilai optimum tegangan listrik 1,83 kV dan jarak nozzle-kolektor 23,50 cm pada simulasi pemintalan elektrik yang dimodelkan oleh Reneker, dkk. Hasil optimasi ini diharapkan dapat membantu eksperimen di laboratorium. Kata kunci: pemintalan elektrik, algoritma genetika, jejari serat, optimasi. AbstractThe study of optimizing two electrospinning parameters, i.e. electric voltage and nozzle-collector distance, was done by employing a genetic algorithm technique in the domain of [1,60] kV and [5,25] cm, the population of 100, the crossover probability of 0.7, and the mutation probability of 0.5. Fiber radius of 155 nm was obtained from the substitution of optimal values of electric voltage of 1.83 kV and nozzle-collector of 23.50 cm, which are from the simulation of a model made by Reneker, et al. This optimization result could help experiments in obtaining desired fiber radius. Keywords: electrospinning, genetic algorithm, fiber radius, optimization.
Penumbuhan Lapisan Tipis Material Sensor Giant Magnetoresistance Berstruktur Sandwich dengan Metode Sputtering Ramli Ramli; Mitra Djamal; Freddy Haryanto; Khairurrijal Khairurrijal
Jurnal Otomasi, Kontrol, dan Instrumentasi Vol 3 No 2 (2011): Jurnal Otomasi, Kontrol, dan Instrumentasi
Publisher : Pusat Teknologi Instrumentasi dan Otomasi (PTIO) Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/joki.2011.3.2.5

Abstract

Material giant magnetoresistance (GMR) menjanjikan untuk diterapkan dalam bidang teknologi penting, salah satunya sebagai sensor medan magnet lemah. Sensor GMR memiliki kelebihan, yakni ukuran yang kecil, daya dan harga yang relatif rendah dibandingkan sensor-sensor magnetik lainnya serta sifat-sifat magnetik dan elektriknya dapat divariasikan dalam rentangan yang sangat lebar. Tujuan dari penelitian ini adalah untuk melihat efek giant magnetoresistance dari lapisan tipis sandwich NiCoFe/Cu/NiCoFe yang ditumbuhkan di atas substrat Si (100) dengan metoda dc-Opposed Target Magnetron Sputtering (dc-OTMS). Parameter penumbuhan yakni; suhu 1000C, laju aliran gas argon sebesar 100 sccm, tekanan 0,52 mTorr, dan tegangan dc 600 volt. Dalam paper ini, akan dibahas pengaruh ketebalan lapisan feromagnetik (NiCoFe) dan ketebalan lapisan non magnetik (Cu) terhadap sifat giant magnetoresistance dari sandwich NiCoFe/Cu/NiCoFe. Hasil pengukuran rasio magnetoresistance memperlihatkan bahwa ketebalan lapisan NiCoFe mempengaruhi nilai rasio GMR, serta makin tebal lapisan NiCoFe, makin kecil medan saturasi, yang ditandai dengan kurva rasio GMR yang makin runcing. Dalam struktur sandwich, kecilnya nilai rasio GMR saat ketebalan NiCoFe rendah, kemungkinan disebabkan oleh hamburan pada permukaan luar seperti antarmuka substrat-film atau buffer layer. Hamburan ini mempengaruhi nilai GMR saat ketebalan lapisan feromagnet lebih kecil dibanding panjang lintasan bebas rata-rata yang berhubungan dengan elektron ber-spin ke atas dan spin ke bawah. Demikian pula halnya dengan ketebalan lapisan non magnetik Cu juga mempengaruhi rasio GMR, dimana rasio GMR semakin berkurang dengan bertambahnya ketebalan lapisan Cu. Hal ini kemungkinan terjadi akibat peningkatan hamburan elektron konduksi yang melintasi lapisan pemisah non magnetik, yang mengurangi aliran elektron diantara lapisan-lapisan feromagnetik dan meningkatkan arus shunting, sehingga mengurangi nilai rasio GMR.  Keywords: feromagnetik; giant magnetoresistance; lapisan tipis; NiCoFe,non magnetik, sensor GMR.