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All Journal Jurnal Matematika & Sains Journal of Mathematical and Fundamental Sciences Journal of Engineering and Technological Sciences Seminar Nasional Informatika (SEMNASIF) Momentum: Physics Education Journal eProceedings of Engineering Community Service Seminar and Community Engagement (COSECANT)
Mamat Rokhmat
Telkom University
Astronomy Chemistry Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Economics, Econometrics & Finance Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Mathematics Physics Other

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The Effect of TiO2 Coating on Pile Penetration Depth in Clay Amalia, Nadya; Asri, Asifa; Rokhmat, Mamat; Sutisna, S.; Viridi, Sparisoma; Abdullah, Mikrajuddin
Journal of Engineering and Technological Sciences Vol 49, No 5 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1874.665 KB) | DOI: 10.5614/j.eng.technol.sci.2017.49.5.6

Abstract

Pile driving tests were conducted using models of concrete piles with titanium dioxide (TiO2) coating and piles without coating. Pile surfaces coated with TiO2 become superhydrophilic, which enables water molecules in clay pores to be attracted to the pile during the pile driving process. The attraction suppresses the compression of the pore water in the clay soil, hence the result of the pile driving tests showed that piles with TiO2 coating could penetrate deeper than piles without coating with the same count of hammer strokes. An examination using FTIR confirmed the formation of bonds between water molecules for piles with coating and the absence of such bonding for piles without coating. Furthermore, it was successfully established that pile surface coating gives different results for pile driving in different clay soils.
Analisis Regresi Sifat Tanah Terhadap Rebound Tiang Pancang Amalia, Nadya; Rokhmat, Mamat; Sutisna, Sutisna; Viridi, Sparisoma; Abdullah, Mikrajuddin
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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Abstract

The behavior of soil around driven pile during pile driving process directly affect the driving process. Two categories of stress are produced during the driving process, i.e. stress along the pile shaft (shear stress) and stress at the end of the pile (compression stress). Since soil is a porous medium, shear and compressive stresses during the driving process will force water to come out of the pores in the soil. Related to hammering and low permeability of the soil at rebound zones such as clay, water can not flow out of the pores and can not be dissipated instantly. As a result, a high pore water pressure will be generated along the shaft and at the end of the pile. Pile coating with titanium dioxide (TiO2) is able to make the pile to be driven deeper than pile without coating with the same count of hammer strokes for pile driving in clay soils. Uniquely, the coating does not give effect to the pile driving in non-cohesive soils. This indicates that the coating is capable in minimizing pile rebound. Regression model is used in this study to identify the characteristics of engineering soil parameters which may cause the rebound phenomenon.
Pengembangan Material Sorben Berbasis Zeolite dan Clay Alam se-bagai Media Desalinasi Air Laut Wibowo, Edy; Rokhmat, Mamat; Sutisna, Sutisna; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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Abstract

We have developed a sorbent based natural materials for seawater desalination application. We used clays, soil, rock and zeolite as raw materials. We conducted a thermal activation process to improve the sorption ability of the materials. The sorption ability of materials were tested to reduce the salinity of seawater and it is expressed by the reduction efficiency. The highest reduction efficiency (4%) was obtained from the activation of the soil at temperature of 600 ° C and the zeolite at a temperature of 200 ° C. It can be seen that the reduction efficiency was linearly increased with the increase of the doses of sorbent. We observed that the sorption ability of zeolite can be enhanced through thermal activation at a relatively low temperature so that it was potentially used as a low-cost sorbent material for seawater desalination.
Aktivitas Fotokatalitik TiO2 yang Dilapiskan pada Polipropilena Berbentuk Lembaran dan Butiran Sutisna, Sutisna; Rokhmat, Mamat; Wibowo, Edy; Rahmayanti, Handika Dany; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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Abstract

The sheet and granule of polypropylene (PP) have been used as the support material for TiO2 catalyst. The TiO2 powder was coated to the polymer surface using a combination of electrostatic and heating methods (for the PP sheet) and thermal milling method (for PP granule). The photocatalytic testing of catalysts conducted on a 300 ml solution of Methylene Blue (MB) with initial concentration of 25 ppm. Under solar ilumination, the catalyst sheets have a higher photocatalytic activity than the catalyst granules.
The Effect of TiO2 Coating on Pile Penetration Depth in Clay Nadya Amalia; Asifa Asri; Mamat Rokhmat; S. Sutisna; Sparisoma Viridi; Mikrajuddin Abdullah
Journal of Engineering and Technological Sciences Vol. 49 No. 5 (2017)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2017.49.5.6

Abstract

Pile driving tests were conducted using models of concrete piles with titanium dioxide (TiO2) coating and piles without coating. Pile surfaces coated with TiO2 become superhydrophilic, which enables water molecules in clay pores to be attracted to the pile during the pile driving process. The attraction suppresses the compression of the pore water in the clay soil, hence the result of the pile driving tests showed that piles with TiO2 coating could penetrate deeper than piles without coating with the same count of hammer strokes. An examination using FTIR confirmed the formation of bonds between water molecules for piles with coating and the absence of such bonding for piles without coating. Furthermore, it was successfully established that pile surface coating gives different results for pile driving in different clay soils.
PEMBUATAN BAHAN DIELEKTRIKA EKSPONENSIAL ANTENA DWITUNGGAL UNIDIREKSIONAL 100 MHz KEATAS DENGAN VSWR 1,5 UNTUK MENINGKATKAN KINERJA KOMUNIKASI DATA Laurentius Aditya HW; Mamat Rokhmat
Seminar Nasional Informatika (SEMNASIF) Vol 1, No 2 (2010): Instrumentational And Robotic
Publisher : Jurusan Teknik Informatika

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Abstract

Penggunaan bahan dielektrik sangat berperan untuk meningkatkan kinerja antena dalam upaya untuk menunjang komunikasi data. Bahan dielektrik yang dipakai untuk kegunaan ini biasanya tidak datar diisi satu bahan saja, tetapi merupakan kombinasi dari beberapa bahan dielektrik. Beberapa penelitian telah berhasil dikembangkan bahan dielektrika dan paduan lainnya untuk penyekat konduktor dalam pengembangan antena Dwitunggal dan antena Bhinneka Tunggal Ika, yaitu antena baru berpita lebar. Khusus untuk antena Dwitunggal Ultra lebar telah pernah dikembangkan bahan dielektrika eksponensiel-diskrit. Untuk kesempatan kali ini akan dibuat dielektrika yang mempunyai impedansi intrisik gradual dan mempunyai impedansi yang berubah secara eksponensial.
Development of a Low-Cost TiO2/CuO/Cu Solar Cell by using Combined Spraying and Electroplating Method Mamat Rokhmat; Edi Wibowo; Sutisna Sutisna; Khairurrijal Khairurrijal; Mikrajuddin Abdullah
Journal of Mathematical and Fundamental Sciences Vol. 50 No. 1 (2018)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2018.50.1.8

Abstract

A simple method is proposed to develop a low-cost TiO2/CuO/Cu based solar cell. The cell is made by employing a lower grade (technical grade) of TiO2 as the active material. CuO powder is synthesized using a wet chemical method and mixed with TiO2 powder to give impurity to the TiO2. A layer of TiO2/CuO is then deposited onto fluorin-doped tin oxide (FTO) by spraying. Copper particles are grown on the spaces between the TiO2 and/or CuO particles by electroplating for more feasible electron migration. The TiO2/CuO/Cu solar cell is finalized by sandwiching a polymer electrolyte between the film and the counter electrode. Current-voltage measurement was performed for various parameters, such as the molarity of NaOH for producing CuO particles, the weight ratio of CuO over TiO2, and the current in the electroplating process. A highest efficiency of 1.40% and a fill factor of 0.37 were achieved by using this combined spray and electroplating method.
Misconceptions on the understanding of flying objects in fluids Edy Wibowo; Naily Ulya; Whibatsu Helvantriyudo; Muhammad Maliki Azyumardi; Fata Hafiduddin; Mamat Rokhmat; Ismudiati Puri Handayani; Abrar Abrar; Nurwulan Fitriyanti; Sutisna Sutisna; Amira Saryati Ameruddin
Momentum: Physics Education Journal Vol. 7 No. 2 (2023)
Publisher : Universitas PGRI Kanjuruhan Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21067/mpej.v7i2.6881

Abstract

The concepts of floating, flying, and sinking object have been studied since junior high school. However, we still often find students' misconceptions regarding the concept, especially of flying objects, even at the university level. This work aims to propose a clarification of the concept of a flying object in the fluid to be correctly described the condition for the flying object. We used eggs, water, and salt solutions to demonstrate sinking, rising, and floating objects in the fluids. The results showed that when the density of the object is the same as the density of the fluid, the position of the object is still at the bottom of the fluid since it was not flying in the middle of the depth of the fluid. But the object does not touch the bottom of the container so that the object's height is zero. This is because the object has not had a driving force (Fd = 0) that pushes the object upward towards the surface of the fluid to float. When the density of the fluid slightly exceeds the density of the object, the object immediately moves upward to the fluid surface - floating phenomenon is started. The greater the difference between the density of the fluid and the density of the object, the faster the object moves towards the surface. The object cannot stay at any position between the bottom and the surface of the fluid. A stable position is reached when the object reaches the surface of the fluid to float. This work is expected to increase students' understanding of flying objects in fluids.
Studi Penentuan Konfigurasi Sistem Induksi Pada Induced Current Electrical Impedance Tomography Yustitia Putri Indraswari; Dudi Darmawan; Mamat Rokhmat
eProceedings of Engineering Vol 2, No 1 (2015): April, 2015
Publisher : eProceedings of Engineering

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Abstract

Salah satu cara untuk mengatasi masalah sensitivitas perubahan konduktivitas objek (distinguishability) yang jauh dari batas adalah dengan pemberian arus melalui penginduksian medan magnet. Cara tersebut biasa disebut induced current electrical impedance tomography (ICEIT). Cara ini diharapkan dapat memberikan distribusi arus induksi yang lebih merata dan menjangkau seluruh permukaan objek. Distribusi arus induksi yang terjadi pada permukaan objek ditentukan oleh distribusi medan magnet. Sehingga, diperlukan pemberian distribusi medan magnet yang homogen. Pemberian distribusi medan magnet homogen ini diprediksi bisa menghasilkan distribusi arus induksi yang lebih representatif menutup seluruh permukaan objek. Oleh karena itu dibutuhkan konfigurasi koil yang tepat agar dapat meningkatkan kemampuan deteksi anomali dan distinguishability agar dihasilkan citra rekonstruksi yang baik. Pada penelitian ini, konfigurasi koil penginduksi diperoleh melalui penentuan jumlah induksi dan posisi setiap induksi yang optimal dan objek yang digunakan berbentuk rectangular dengan bentuk koil yang sama. Dari hasil simulasi dengan variasi jumlah induksi diperoleh bahwa distribusi medan magnet semakin homogen jika memberikan jumlah induksi lebih banyak pada objek. Variasi posisi induksi pada suatu konfigurasi koil tertentu akan menentukan kehomogenan distribusi medan magnet. Kata Kunci : induced current electrical impedance tomography, konfigurasi koil, rectangular coil, kehomogenan medan magnet
Pengaruh Penyisipan Tembaga Cu Menggunakan Metode Pulse Plating Pada Sel Surya TiO2 Ramadan Gumilar; Mamat Rokhmat; Edy Wibowo
eProceedings of Engineering Vol 1, No 1 (2014): Desember, 2014
Publisher : eProceedings of Engineering

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Abstract

Pada penelitian ini dipelajari pengaruh penyisipan logam tembaga pada sel surya organik. Penyisipan logam Cu pada lapisan TiO2 dilakukan dengan metode pulse plating pada variasi tegangan dan duty cycle. Material TiO2 yang dicampurkan dengan aquades lalu dideposisikan pada FTO menggunakan metode spray. Lapisan TiO2 disisipi logam tembaga Cu dengan metode pulse plating sehingga membentuk lapisan kontak logam yang menjadi lintasan bagi elektron untuk mengalir lebih cepat menuju elektroda (FTO). Polimer elektrolit digunakan sebagai transport hole yang tersusun atas campuran LiOH dan PVA. Struktur sel surya yang telah dibuat dikarakterisasi dengan menggunakan I-V meter Keithley 617 untuk mengetahui performansi sel surya. Karakteristik I-V menunjukan terjadi peningkatan efisiensi sel surya TiO2 disisipi logam Cu dengan pulse plating sebesar 0,147% dibandingkan dengan sel surya TiO2 disisipi logam Cu dengan elektroplating sebesar 0,04%. Kata kunci: TiO2 , pulse plating, pulse reverse elekrodeposisi, metode spray
Co-Authors A.A. Ketut Agung Cahyawan W Abrar Ismardi Ade Istiqomah Ahmad Barelvie Rasyid Ahmad Qurthobi Akmal Faizal Aldy Hidayat Amalia, Nadya Amaliyah Rohsari Indah Utami Amira Saryati Ameruddin Andre Swardana Anjas Aji Budiatma Aripriantoni Aripriantoni Asep Suhendi Asifa Asri Christina Christina Diky Meidianto Dudi Darmawan Edi Wibowo Edy Wibowo Eka Muslim Budiansyah Eriz Aprizki Erni Dwi Sumaryatie Erpanda Surya Alam Ery Djunaedi Faisah Nasution Faris Hanif Rahman Fata Hafiduddin Fathur Rahman Febriyanti Novitasari Fuad Fauzi Wibowo Hertiana Bethaningtyas Dyah K. Holia Onggo Ihsan Maulidin Indra Wahyudin Fathonah Iqbal Dwi Cahyo Ismudiati Puri Handayani Khairurrijal Khairurrijal Khairurrijal khairurrijal Laurentius Aditya HW Mayanisa Nurfithri Mikrajuddin Abdullah Mikrajuddin Abdullah Mikrajuddin Abdullah Muhammad Maliki Azyumardi Nabilla Syahvalensi Nadya Amalia Nadya Amalia Naily Ulya Natalita Maulani Nursam Nia Malasari Nurwulan Fitriyanti Rahman Aditya Rahmayanti, Handika Dany Ramadan Gumilar Reza Fauzi Iskandar S. Sutisna Shobih Shobih Sparisoma Viridi Sparisoma Viridi Sutisna Sutisna Sutisna, S. Tania Verasta Theresia Deviyana Gunawan Wahyu Kurniawan Whibatsu Helvantriyudo Wildan Bagus Firmansyah Yustitia Putri Indraswari Zahara Ramadhayanti Karyuni