Sintering of Al-Si-Fe-Cu-Mg-SiC powder prepared by gas atomization process

Haris Rudianto 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.S1

Aluminum powder metallurgy (P/M) composites offer high mechanical properties, low coefficient of thermal expansion and good weight strength ratio with homogeneous distribution of the reinforcement phase. This work aims to investigate the mechanical properties of pre-mixed aluminum matrix composites with different chemical compositions. Mixed powers of Al14Si-2.5Cu-0.5Mg and Al-14.5Si-1.85Cu-2.85Fe-0.8Mg with 10% volume fraction of SiC (12 µm) were used as starting powders. Reaction during sintering and chemical composition of the starting powders played important role on the sintered properties. T6 heat-treatment was carried out to produce fine precipitates to impede the movement of dislocation to increase their mechanical properties. The heat treatment involved solutionizing materials followed by water quenching and artificial aging.

Microcredit for rural poverty alleviation and social well-being: A study of Sabah, Malaysia

Haris Abd. Wahab,William Bunyau,M. Rezaul Islam 한국사회복지학회 2018 Asian Social Work and Policy Review Vol.12 No.1

Microcredit is an influential intervention used to alleviate poverty and improve social well-being in rural communities in Sabah, Malaysia. This study examined the effects of a microcredit scheme, Amanah Ikhtiar Malaysia (AIM), on the well-being of these communities. Using a survey method, a pre-tested interview schedule was administered to 277 AIM recipients in Sabah, Malaysia. Social well-being was examined based on the three indicators of Midgley’s social development approach: the management of problems, the fulfillment of basic needs, and social opportunities provided. AIM microcredit schemes were successful in improving the well-being of AIM recipients, although the recipients faced a number of problems, including unemployment, lack of education, and access to public services and healthcare facilities. The findings of this study represent a useful guideline to the AIM authority, development practitioners, policymakers, and governmental organization and nongovernmental organization workers

A New Excitation Control for Multimachine Power Systems Ⅱ : Robustness and Disturbance Attenuation Analysis

Haris E. Psillakis,Antonio T. Alexandridis 대한전기학회 2005 International Journal of Control, Automation, and Vol.3 No.2

In this paper a new adaptive, decentralized excitation control scheme proposed to enhance the transient stability of multimachine power systems is extensively analyzed with respect to its robustness and disturbance attenuation. As shown in the paper, both robustness and disturbance attenuation can be effectively improved by suitably selecting the design parameters of the proposed controller. Particularly, some simple rules for the selection of the control gains and the adaptation parameters are extracted which, as it is proven, may be essential for the system performance. Simulation tests on a two generator infinite bus power system absolutely confirm the theoretical results.

A New Excitation Control for Multimachine Power Systems Ⅰ : Decentralized Nonlinear Adaptive Control Design and Stability Analysis

Haris E. Psillakis,Antonio T. Alexandridis 대한전기학회 2005 International Journal of Control, Automation, and Vol.3 No.2

In this paper a new excitation control scheme that improves the transient stability of multimachine power systems is proposed. To this end the backstepping technique is used to transform the system to a suitable partially linear form. On this system, a combination of both feedback linearization and adaptive control techniques are used to confront the nonlinearities. As shown in the paper, the resulting nonlinear control law ensures the uniform boundedness of all the state and estimated variables. Furthermore, it is proven that all the error variables are uniformly ultimately bounded (VUE) i.e. they converge to arbitrarily selected small regions around zero in finite-time. Simulation tests on a two generator infinite bus power system demonstrate the effectiveness of the proposed control.

Expression Profile of Genes Modulated by Aloe emodin in Human U87 Glioblastoma Cells

Haris, Khalilah,Ismail, Samhani,Idris, Zamzuri,Abdullah, Jafri Malin,Yusoff, Abdul Aziz Mohamed Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with $58.6{\mu}g/ml$ for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.

An Improved Particle swarm optimization Algorithm for complex nonlinear Problems

Haris Muhammad,Jiyeon Park,Jun Hur,Haewoon Nam 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.2

Particle swarm optimizer (PSO) is a very logical algorithm to obtained best solutions in engineering and mathematical field. However the traditional PSO algorithm and the existing different algorithm have the issue of delayed and slow convergence speed in different application problems. To deal with such kind of problems an Improved particle swarm optimization (PSO) is proposed in this paper. The proposed Improved PSO algorithm is been tested on some famous complex benchmark functions.

Optimal Reservoir Rule Curves under Climatic and Land Use Changes for Lampao Dam using Genetic Algorithm

Haris Prasanchum,Anongrit Kangrang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

The uncertainties of climate and land use changes have directly impacted the inflows and water resource management in reservoirs. The optimal reservoir rule curve is a tool for the mitigation of droughts and floods, which are situations that occur often. This study applied the Genetic Algorithm (GA) to connect with a reservoir simulation model to search optimal reservoir rule curves during the period 2014-2064 for Lampao Reservoir located in the northeast of Thailand. It considered the impact of climate change with the PRECIS model under two emission scenarios: A2 and B2, and created future land use maps using the CA Markov model, including an assessment of the future inflow into the reservoir using the hydrologic model SWAT in the Upper-Lampao Basin, which is the headwater area of the reservoir. The results showed that the new rule curves were improved by the GA connected simulation model and can mitigate the frequency of water shortage situations and the releases of excess water during inflow changes in the future, including a situation where the water demand increased due to the expansion of irrigation areas.

Polarization Re-Configurable Antenna with Increase Gain for Small Satellites

Haris Mohammad,Khalil Ruhul Amin,Saeed Nasir 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.6

Future small satellites require the development of reconfi gurable antennas. Designing such antennas, especially single port patch antennas with circular polarization is a challenging task. Therefore, we propose both right-hand/left-hand circularly polarized (RHCP/LHCP) antenna which can reconfi gure. The proposed antenna follows patch topology with E-shape that is single-layer and single-feed with two RF switches. The switches can alter the polarization in real-time. We also show various properties of the proposed antenna, such as radiation pattern, impedance matching, axial ratio, and bandwidth through simulations and measurements. The proposed model shows excellent performance and agrees well with the measurements. The performance of the antenna shows an eff ective bandwidth of 2.45 GHz–2.82 GHz with a maximum gain of 9.88 dB at 2.55 GHz. The symmetry of the antenna radiation is preserved by switching between the LHCP and RHCP polarization modes.

Meta Case Study of Public Services Based Sub-District Organization Models: Context of Indonesia

( Haris Faozan ) 한국정책학회 2011 International Journal of Policy Studies Vol.2 No.1

Sub-district is one of the organization peripheral area that has a crucial role in public services. Law number 32, year 2001, states that in addition from having attributive duties, sub-district is also devolved in delegated authorities. However, both main tasks can not be performed optimally. The policies concerned with sub-district organization indicates complicated issues, and the public services of the sub-district remain low-performed. This paper presents models of sub-district organization that anticipate the needs and priorities of public services. This research is a meta applied case study. This study used research data about sub-district organizations in Indonesia. The analytical methodology was in-depth qualitative analysis based on the findings of the previous case studies. This study resulted in important findings. The design of sub-district organizations remained to have low performance based on the dimensions of its organizational structure. This internal drawback led to poor public service delivery. Based on these findings, this study recommends three sub-district organization models. One of these models can be selected by local government to redesign its sub-district organization, in accordance with organizational capacity and public service demands and priorities.

[독자투고] 고대역폭 전원 모듈로 고전압 회선의 리플 제거 간섭 억제

Haris Muhedinovic,최연규(번역자) 한국자동차공학회 2024 오토저널 Vol.46 No.3