Hydrothermal assisted synthesis of titanium dioxide nanoparticles modified graphene with enhanced photocatalytic performance

Rahmat Hidayat,Rahmat Hidayat,Tawfik A. Saleh 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

Water purification is a global issue, and most traditional methods have several drawbacks. As a result,new methods and materials must be devised to address the problem of water filtration. The hydrophobicTiO2-ZnO/rGO has been synthesized via single-step hydrothermal methods for the efficiency and effectiveindigo carmine (IC) solution degradation. The characterization of hydrophobic TiO2-ZnO/rGO has shownthat the material has a high contact angle value of around 103.6. Several photocatalytic parameters, pHof IC solution, the dosage of catalyst, and light intensity, were optimized for obtaining the highest degradationefficiency. The results of the photocatalytic study showed that the IC dye degradation process wascontrolled by superoxide anion radical (O2 radicals) to produce more specific products. Modificationswith hydrophobic compounds such as hexamethyldisilizane (HDMS) showed that they could increasethe photocatalytic properties and reusability of the material with a degradation percentage value of upto 95% with a constant rate of 0.0361 min1. Based on these results, this material has the potential tobe further developed for micro and complex photodegradation and self-cleaning materials.

A Novel Hybrid Detection Scheme for Combination of Spatial Modulation and Non-Orthogonal Multiple Access

Rahmat Faddli Siregar,Fahri Wisnu Murti,Soo Young Shin 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.6

Fuzzy Logic Application in Fault Diagnosis of Transformers Using Dissolved Gases

Rahmat-Allah Hooshmand,Mahdi Banejad 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.3

One of the problems with the fault diagnosis of transformers based on dissolved gas is the inability to match the result of the different standards of fault diagnosis with real world standards. In this paper, the results of the different standards are analyzed using fuzzy logic and then compared with the empirical test. The proposed method is based on the standards and guidelines of the International Electrotechnical Commission (IEC), the Central Electric Generating Board (CEGB), and the American Society for Testing and Material (ASTM) and its main task is to assist the conventional gas ratio method. The comparison between the suggested method and existing methods indicates the capability of the suggested method in the on-line fault diagnosis of transformers, In addition, in some cases the existing standards are not able to diagnose the fault. For theses instances, the presented method has the potential of diagnosing the fault. In this paper, the information of three real transformers is used to show the capability of the suggested method in diagnosing the fault. The results validate the capability of the presented method in fault diagnosis of the transformer.

Higher order nonlocal nonlinear boundary value problems for fractional differential equations

Rahmat Ali Khan 대한수학회 2014 대한수학회보 Vol.51 No.2

In this paper, we study the method of upper and lower so- lutions and develop the generalized quasilinearization technique for the existence and approximation of solutions to some three-point nonlocal boundary value problems associated with higher order fractional differ- ential equations of the type cDq 0+u(t) + f(t, u(t)) = 0, t ∈(0, 1) u′(0) = u′(π), u′′(0) = 0, u′′′(0) = 0, . . . , u(n−1)(0) = 0, u(1) = u(π), where, n−1 < q < n, n(≥ 3) ∈ N, 0 < π,γ, <δ 1 and cDq 0+ is the Caputo fractional derivative of order q. The nonlinear function f is assumed to be continuous. In this paper, we study the method of upper and lower so- lutions and develop the generalized quasilinearization technique for the existence and approximation of solutions to some three-point nonlocal boundary value problems associated with higher order fractional differ- ential equations of the type cDq 0+u(t) + f(t, u(t)) = 0, t ∈ (0, 1) u′(0) = u′(π), u′′(0) = 0, u′′′(0) = 0, . . . , u(n−1)(0) = 0, u(1) = u(π), where, n−1 < q < n, n(≥3) ∈ N, 0 < π,γ, δ < 1 and cDq 0+ is the Caputo fractional derivative of order q. The nonlinear function f is assumed to be continuous.

Bio-inspired neuro-symbolic approach to diagnostics of structures

Rahmat A. Shoureshi,Tracy Schantz,Sun W. Lim 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.7 No.3

Recent developments in Smart Structures with very large scale embedded sensors and actuators have introduced new challenges in terms of data processing and sensor fusion. These smart structures are dynamically classified as a large-scale system with thousands of sensors and actuators that form the musculoskeletal of the structure, analogous to human body. In order to develop structural health monitoring and diagnostics with data provided by thousands of sensors, new sensor informatics has to be developed. The focus of our on-going research is to develop techniques and algorithms that would utilize this musculoskeletal system effectively; thus creating the intelligence for such a large-scale autonomous structure. To achieve this level of intelligence, three major research tasks are being conducted: development of a Bio-Inspired data analysis and information extraction from thousands of sensors; development of an analytical technique for Optimal Sensory System using Structural Observability; and creation of a bio-inspired decision-making and control system. This paper is focused on the results of our effort on the first task, namely development of a Neuro-Morphic Engineering approach, using a neuro-symbolic data manipulation, inspired by the understanding of human information processing architecture, for sensor fusion and structural diagnostics.

Multi-User Scheme in Spatial Modulation

Rahmat Faddli Siregar,Fahri Wisnu Murti,Seong Chae,Soo Young Shin 한국통신학회 2018 한국통신학회 학술대회논문집 Vol.2018 No.1

Identification of druggable genes for multiple myeloma based on genomic information

Rahmat Dani Satria,Lalu Muhammad Irham,Wirawan Adikusuma,Anisa Nova Puspitaningrum,Arief Rahman Afief,Riat El Khair,Abdi Wira Septama Korea Genome Organization 2023 Genomics & informatics Vol.21 No.3

Multiple myeloma (MM) is a hematological malignancy. It is widely believed that genetic factors play a significant role in the development of MM, as investigated in numerous studies. However, the application of genomic information for clinical purposes, including diagnostic and prognostic biomarkers, remains largely confined to research. In this study, we utilized genetic information from the Genomic-Driven Clinical Implementation for Multiple Myeloma database, which is dedicated to clinical trial studies on MM. This genetic information was sourced from the genome-wide association studies catalog database. We prioritized genes with the potential to cause MM based on established annotations, as well as biological risk genes for MM, as potential drug target candidates. The DrugBank database was employed to identify drug candidates targeting these genes. Our research led to the discovery of 14 MM biological risk genes and the identification of 10 drugs that target three of these genes. Notably, only one of these 10 drugs, panobinostat, has been approved for use in MM. The two most promising genes, calcium signal-modulating cyclophilin ligand (CAMLG) and histone deacetylase 2 (HDAC2), were targeted by four drugs (cyclosporine, belinostat, vorinostat, and romidepsin), all of which have clinical evidence supporting their use in the treatment of MM. Interestingly, five of the 10 drugs have been approved for other indications than MM, but they may also be effective in treating MM. Therefore, this study aimed to clarify the genomic variants involved in the pathogenesis of MM and highlight the potential benefits of these genomic variants in drug discovery.

Real-Coded Genetic Algorithm Based Design and Analysis of an Auto-Tuning Fuzzy Logic PSS

Rahmat-Allah Hooshmand,Mohammad Ataei 대한전기학회 2007 Journal of Electrical Engineering & Technology Vol.2 No.2

One important issue in power systems is dynamic instability due to loosing balance relation between electrical generation and a varying load demand that justifies the necessity of stabilization. Moreover, Power System Stabilizer (PSS) must have capability of producing appropriate stabilizing signals over a wide range of operating conditions and disturbances. To overcome these drawbacks, this paper proposes a new method for robust design of PSS by using an auto-tuning fuzzy control in combination with Real-Coded Genetic Algorithm (RCGA). This method includes two fuzzy controllers; internal fuzzy controller and supervisor fuzzy controller. The supervisor controller tunes the internal one by on-line applying of nonlinear scaling factors to inputs and outputs. The RCGA￢based method is used for off-line training of this supervisor controller. The proposed PSS is tested in three operational conditions; nominal load, heavy load, and in the case of fault occurrence in transmission line. The simulation results are provided to compare the proposed PSS with conventional fuzzy PSS and conventional PSS. By evaluating the simulation results, it is shown that the performance and robustness of proposed PSS in different operating conditions is more acceptable.

Modification of ICI Self Cancellation for Mitigating Inter Carrier Interference Presence in OFDM System

Rahmat Faddli Siregar,Fahri Wisnu Murti,Soo Young Shin(신수용) 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.1

Development of a novel ozone gas sensor based on sol-gel fabricated photonic crystal

Rahmat, M.,Maulina, W.,Isnaeni,Miftah, D.Y.N.,Sukmawati, N.,Rustami, E.,Azis, M.,Seminar, K.B.,Yuwono, A.S.,Cho, Y.H.,Alatas, H. Elsevier Sequoia 2014 Sensors and actuators. A Physical Vol.220 No.-

We have developed a novel ozone gas sensor based on one dimensional photonic crystal with two defects. In this platform, the gas is dissolved in a specific neutral buffer kalium iodide reagent to include the Beer Lambert effect. The corresponding photonic crystal which was fabricated by using sol-gel method consists of a high refractive index layer of TiO<SUB>2</SUB> and a low refractive index layer of SiO<SUB>2</SUB>. Prior to the fabrication of corresponding photonic crystal, we grew the TiO<SUB>2</SUB> and SiO<SUB>2</SUB> single layer separately in order to ensure that the performance of each layer fulfilled the required characteristics provided by our simulation. After that, the fabrication processed was conducted layer-by-layer and inspected by spectrophotometer. The performance test of the fabricated photonic crystal, including its validation, accuracy and sensitivity, was then conducted through spectroscopic treatment and we used ozonizer as the gas source. Validation test was performed by comparing the results with measurement using NBKI method and showed a good agreement. It was found that the accuracy value is up to 98.75%. Based on a statistical approach, we found that the limit of detection is 1.067μg/m<SUP>3</SUP> ambient air.