Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504311
Miloš Kopa, T. Tichý
Portfolio selection problem is one of the most important issues within financial risk management and decision making. It concerns both, financial institutions and their regulator/supervisor bodies. A very challenging question in this context is whether there is some impact of alternative dependency/concordance measures on the efficiency of optimal portfolios. Therefore, the alternative ways of portfolio comparisons were developed, among them a stochastic dominance approach is one of the most popular one. In particular, the definition of the second-order stochastic dominance (SSD) relation uses comparisons of either twice cumulative distribution functions or expected utilities. Alternatively, one can define SSD relation using cumulative quantile functions or conditional value at risk. The task of this paper is therefore to examine and analyze the SSD efficiency of min-var portfolios that are selected on the basis of alternative concordance matrices set up on the basis of either Spearman rho or Kendall tau. It is empirically documented that only Pearson measure in Markowitz model identified a portfolio that can be of interest for at least one risk averse investor. Moreover, a portfolio based on Kendall measure is very poor (at least in terms of SSD efficiency).
{"title":"Efficiency analysis of classic risk minimizing portfolios","authors":"Miloš Kopa, T. Tichý","doi":"10.1109/CHUSER.2012.6504311","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504311","url":null,"abstract":"Portfolio selection problem is one of the most important issues within financial risk management and decision making. It concerns both, financial institutions and their regulator/supervisor bodies. A very challenging question in this context is whether there is some impact of alternative dependency/concordance measures on the efficiency of optimal portfolios. Therefore, the alternative ways of portfolio comparisons were developed, among them a stochastic dominance approach is one of the most popular one. In particular, the definition of the second-order stochastic dominance (SSD) relation uses comparisons of either twice cumulative distribution functions or expected utilities. Alternatively, one can define SSD relation using cumulative quantile functions or conditional value at risk. The task of this paper is therefore to examine and analyze the SSD efficiency of min-var portfolios that are selected on the basis of alternative concordance matrices set up on the basis of either Spearman rho or Kendall tau. It is empirically documented that only Pearson measure in Markowitz model identified a portfolio that can be of interest for at least one risk averse investor. Moreover, a portfolio based on Kendall measure is very poor (at least in terms of SSD efficiency).","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"75 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115075068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504340
O. Althuwaynee, B. Pradhan, A. R. Mahmud, Z. Yusoff
The main objective of this research is to evaluate the spatial prediction of potential slope failures in Kuala Lumpur and surrounding areas using an index of entropy based statistical model. Based on potential information of entropy method (IoE), subjective weights were calculated for fourteen landslide conditioning factors used in this study such as, (slope, aspect, curvature, altitude, surface roughness, lithology, distance from faults, NDVI (normalized difference vegetation index), land cover, distance from drainage, distance from road, SPI (stream power index), soil type and precipitation). A landslide inventory map of the study area was produced using previous reports and aerial photographs interpretation aided with extensive field survey and total of 220 main scarps were identified. Out of this, 153 (70%) landslide locations were used to build the IoE model, while remaining 66 (30%) landslide locations were used for validation purpose. For validation, the area under the curve (AUC) was used to quantify the predictive performance of the employed IoE model. The validation results show that the prediction accuracy of the model is 0.80 (80%) and the success rate equals to 0.81 (81%) that consider fine indicator of the reliability of bivariate model based IoE model employed in this study.
{"title":"Prediction of slope failures using bivariate statistical based index of entropy model","authors":"O. Althuwaynee, B. Pradhan, A. R. Mahmud, Z. Yusoff","doi":"10.1109/CHUSER.2012.6504340","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504340","url":null,"abstract":"The main objective of this research is to evaluate the spatial prediction of potential slope failures in Kuala Lumpur and surrounding areas using an index of entropy based statistical model. Based on potential information of entropy method (IoE), subjective weights were calculated for fourteen landslide conditioning factors used in this study such as, (slope, aspect, curvature, altitude, surface roughness, lithology, distance from faults, NDVI (normalized difference vegetation index), land cover, distance from drainage, distance from road, SPI (stream power index), soil type and precipitation). A landslide inventory map of the study area was produced using previous reports and aerial photographs interpretation aided with extensive field survey and total of 220 main scarps were identified. Out of this, 153 (70%) landslide locations were used to build the IoE model, while remaining 66 (30%) landslide locations were used for validation purpose. For validation, the area under the curve (AUC) was used to quantify the predictive performance of the employed IoE model. The validation results show that the prediction accuracy of the model is 0.80 (80%) and the success rate equals to 0.81 (81%) that consider fine indicator of the reliability of bivariate model based IoE model employed in this study.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123038065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504424
M. Rahim, N. Rahimi, A. Hussain, J. Mahmud, Mazuki Musa
Composite laminates exhibit complex failure behaviour as they are heterogeneous and orthotropic. Each ply or lamina that formed the laminates might yield and rupture at a different stress value. This phenomenon leads to first ply failure (FPF) behaviour which emphasised on the condition where a ply that fails first. This work investigated the influence of three parameters, i.e., material property, aspect ratio, and number of plies, each considered separately, to FPF of the laminates. Analyses were carried out to determine the FPF loads based on the Maximum Stress criterion using a commercially available finite element software i.e. ANSYS (ANSYS v12.1, 2009 SAS IP, Inc.). The results have shown that carbon laminate failed at the highest failure load compared to boron and graphite laminates. It was also found that the FPF load increased with the increasing of aspect ratio and plate thickness at all angles.
复合材料层压板具有非均质性和正交异性，具有复杂的破坏行为。形成层压板的每一层或每一层可能在不同的应力值下屈服和破裂。这种现象导致了首层失效(FPF)行为，这种行为强调了首层失效的情况。这项工作调查了三个参数的影响，即材料性能，长宽比和层数，每一个单独考虑的层压板的FPF。利用市售有限元软件ANSYS (ANSYS v12.1, 2009 SAS IP, Inc.)，根据最大应力准则对FPF载荷进行了分析。结果表明，与硼和石墨层压板相比，碳层压板在最高失效载荷下失效。在各个角度上，FPF载荷随长径比和板厚的增加而增加。
{"title":"Parametric study on failure analysis of composite laminate under uniaxial tensile loading","authors":"M. Rahim, N. Rahimi, A. Hussain, J. Mahmud, Mazuki Musa","doi":"10.1109/CHUSER.2012.6504424","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504424","url":null,"abstract":"Composite laminates exhibit complex failure behaviour as they are heterogeneous and orthotropic. Each ply or lamina that formed the laminates might yield and rupture at a different stress value. This phenomenon leads to first ply failure (FPF) behaviour which emphasised on the condition where a ply that fails first. This work investigated the influence of three parameters, i.e., material property, aspect ratio, and number of plies, each considered separately, to FPF of the laminates. Analyses were carried out to determine the FPF loads based on the Maximum Stress criterion using a commercially available finite element software i.e. ANSYS (ANSYS v12.1, 2009 SAS IP, Inc.). The results have shown that carbon laminate failed at the highest failure load compared to boron and graphite laminates. It was also found that the FPF load increased with the increasing of aspect ratio and plate thickness at all angles.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123459206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504344
Muhammad Umar Zulkefli
This paper presents a performance-based seismic analysis of increasingly preferred short span bridge in Malaysia: integral bridge (IB). In the case of the integral bridge the pier and deck were monolithic so the thermal contraction and expansion of the deck is allowed for by the flexibility in the pier and abutments. The bridge was analyzed with low intensity bidirectional earthquake excitation with assessment of the structural responses of the bridge. The elastic response spectrum derived from Eurocode 8 (EN 1998) was used in Finite Element Analysis (FEA) software SAP2000 for the bridge analysis and simulation. The bridge was then being performed again with the same analysis with an inclusion of link component represented seismic rubber isolator. The analysis showed that even though the displacements were reduced for the integral bridge, the acceleration, and structural responses were higher than for the bridge with seismic rubber isolator.
本文提出了一种基于性能的地震分析越来越受欢迎的马来西亚短跨桥梁:整体桥(IB)。在整体桥梁的情况下，桥墩和桥面是整体的，因此桥面的热收缩和膨胀是由桥墩和桥台的灵活性所允许的。对桥梁进行了低烈度双向地震激励分析，并对桥梁的结构反应进行了评估。根据欧洲规范8 (EN 1998)导出的弹性反应谱在有限元分析软件SAP2000中进行了桥梁分析和模拟。然后对桥梁进行了同样的分析，其中包含了代表地震橡胶隔震器的链接组件。分析表明，整体隔震桥的位移虽有所减小，但加速度和结构响应均高于橡胶隔震桥。
{"title":"Elastic response of integral bridge under Malaysian low intensity earthquake","authors":"Muhammad Umar Zulkefli","doi":"10.1109/CHUSER.2012.6504344","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504344","url":null,"abstract":"This paper presents a performance-based seismic analysis of increasingly preferred short span bridge in Malaysia: integral bridge (IB). In the case of the integral bridge the pier and deck were monolithic so the thermal contraction and expansion of the deck is allowed for by the flexibility in the pier and abutments. The bridge was analyzed with low intensity bidirectional earthquake excitation with assessment of the structural responses of the bridge. The elastic response spectrum derived from Eurocode 8 (EN 1998) was used in Finite Element Analysis (FEA) software SAP2000 for the bridge analysis and simulation. The bridge was then being performed again with the same analysis with an inclusion of link component represented seismic rubber isolator. The analysis showed that even though the displacements were reduced for the integral bridge, the acceleration, and structural responses were higher than for the bridge with seismic rubber isolator.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"273 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123493248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504398
R. Khan, Z. Ghazali, M. S. Liew
Construction and manufacturing are the key sectors of Malaysian economy. These sectors play significant role in socio economic development of Malaysia, generate substantial amount of revenue for Malaysian economy and provide employment opportunities to number of skilled, semi-skilled, unskilled, educated and uneducated people. Construction and manufacturing sectors are greatly interlinked with each other through their backward and forward linkages. The purpose of this study is to measures the causal relationship and linkage between construction and manufacturing sectors of Malaysia by using sophisticated econometric approach. Granger causality test and the vector auto regression (VAR) technique is used to determine the causal relationship between the two sectors and measure the effect of changes in output of one sector on the output of other sector. The results of the study show that there is strong correlation and bidirectional causal relationship exists between the construction and manufacturing sector of Malaysia during the study period 2000–2010. The construction sector takes approximately 21 months to respond the impact of shocks coming from manufacturing sector while the manufacturing sector responding time is 15 months.
{"title":"An empirical analysis of linkage between the construction and manufacturing sectors of Malaysia (2000–2010)","authors":"R. Khan, Z. Ghazali, M. S. Liew","doi":"10.1109/CHUSER.2012.6504398","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504398","url":null,"abstract":"Construction and manufacturing are the key sectors of Malaysian economy. These sectors play significant role in socio economic development of Malaysia, generate substantial amount of revenue for Malaysian economy and provide employment opportunities to number of skilled, semi-skilled, unskilled, educated and uneducated people. Construction and manufacturing sectors are greatly interlinked with each other through their backward and forward linkages. The purpose of this study is to measures the causal relationship and linkage between construction and manufacturing sectors of Malaysia by using sophisticated econometric approach. Granger causality test and the vector auto regression (VAR) technique is used to determine the causal relationship between the two sectors and measure the effect of changes in output of one sector on the output of other sector. The results of the study show that there is strong correlation and bidirectional causal relationship exists between the construction and manufacturing sector of Malaysia during the study period 2000–2010. The construction sector takes approximately 21 months to respond the impact of shocks coming from manufacturing sector while the manufacturing sector responding time is 15 months.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115245301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504417
N. Isa, Y. Mohd, N. Yury
This study was carried out in order to investigate the formation of hydroxyapatite (HAp) coatings on etched Ti mesh substrate using electrodeposition technique. The coatings were deposited from solution containing CaCl2 and NH4H2PO4 (with Ca/P ratio being 1.67) by maintaining cathodic potentials for − 0.8 V and − 1.5 V vs Ag/AgCl for 30 min at 80 °C. On the other hand, chitosan solution was also added into bath solution to study its effect on coatings morphology. The surface morphology and the elemental compositions of the Ti surface before and after deposition were observed by FESEM and EDAX, respectively. Etching process has changed the morphology of the Ti surface from smooth to rough surface. HAp coatings deposited at − 0.8 V and − 1.5 V have similar morphology with flower-like structure. However, the coatings are more dense and compact when deposited at higher potential (i.e.: − 1.5 V). When chitosan was added into bath solution, the morphological structure of the coating was significantly changed from flower-like structure to flake-like structure interconnected with net-like structure of chitosan.
本研究是为了研究电沉积技术在蚀刻钛网基体上形成羟基磷灰石(HAp)涂层。在CaCl2和NH4H2PO4 (Ca/P比值为1.67)溶液中，在80°C条件下，在−0.8 V和−1.5 V vs Ag/AgCl阴极电位下沉积30 min。另一方面，在镀液中加入壳聚糖溶液，研究其对涂层形貌的影响。利用FESEM和EDAX分别观察了沉积前后Ti表面的形貌和元素组成。蚀刻工艺使钛表面形貌由光滑变为粗糙。在−0.8 V和−1.5 V下沉积的HAp涂层形貌相似，呈花状结构。而在−1.5 V电位下沉积时，涂层更加致密致密。当壳聚糖加入到浴液中时，涂层的形态结构发生了明显的变化，从花状结构转变为与壳聚糖网状结构相互连接的片状结构。
{"title":"Electrodeposition of hydroxyapatite (HAp) coatings on etched titanium mesh substrate","authors":"N. Isa, Y. Mohd, N. Yury","doi":"10.1109/CHUSER.2012.6504417","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504417","url":null,"abstract":"This study was carried out in order to investigate the formation of hydroxyapatite (HAp) coatings on etched Ti mesh substrate using electrodeposition technique. The coatings were deposited from solution containing CaCl2 and NH4H2PO4 (with Ca/P ratio being 1.67) by maintaining cathodic potentials for − 0.8 V and − 1.5 V vs Ag/AgCl for 30 min at 80 °C. On the other hand, chitosan solution was also added into bath solution to study its effect on coatings morphology. The surface morphology and the elemental compositions of the Ti surface before and after deposition were observed by FESEM and EDAX, respectively. Etching process has changed the morphology of the Ti surface from smooth to rough surface. HAp coatings deposited at − 0.8 V and − 1.5 V have similar morphology with flower-like structure. However, the coatings are more dense and compact when deposited at higher potential (i.e.: − 1.5 V). When chitosan was added into bath solution, the morphological structure of the coating was significantly changed from flower-like structure to flake-like structure interconnected with net-like structure of chitosan.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124746816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504380
Mohamad Osman, Siew-Phaik Loke, M. N. Zakaria, A. Downe
In this study, we examined the effect of perfectionism on learning programming using different computer applications, and the levels of motivational and attainment. Three representative multimedia-oriented programming tools are used: Visual Basic Express, Scratch and a 2D-Programmable PyGame Based Computer Game. A total of 591 of secondary school students located in Perak region were sampled. The respondents were categorized according to the degree of perfectionisms using the Frost Multidimensional Perfectionisms Scale (FMPS). We found that there were significant differences in both motivational and attainment levels between different programming learning tools. Specifically, for both low-positive and high-positive perfectionist groups, the students who use Scratch and PyGame tend to score high in the motivational and attainment variables when compared to the Visual Basic Express. Scratch and PyGame seem to be more attractive and thus make learning programming more effective. Our findings provide insights to educators in schools who are selecting and using appropriate software for teaching programming courses.
{"title":"Secondary students' perfectionism and their response to different programming learning tools","authors":"Mohamad Osman, Siew-Phaik Loke, M. N. Zakaria, A. Downe","doi":"10.1109/CHUSER.2012.6504380","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504380","url":null,"abstract":"In this study, we examined the effect of perfectionism on learning programming using different computer applications, and the levels of motivational and attainment. Three representative multimedia-oriented programming tools are used: Visual Basic Express, Scratch and a 2D-Programmable PyGame Based Computer Game. A total of 591 of secondary school students located in Perak region were sampled. The respondents were categorized according to the degree of perfectionisms using the Frost Multidimensional Perfectionisms Scale (FMPS). We found that there were significant differences in both motivational and attainment levels between different programming learning tools. Specifically, for both low-positive and high-positive perfectionist groups, the students who use Scratch and PyGame tend to score high in the motivational and attainment variables when compared to the Visual Basic Express. Scratch and PyGame seem to be more attractive and thus make learning programming more effective. Our findings provide insights to educators in schools who are selecting and using appropriate software for teaching programming courses.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123625652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504441
A. Abdul-Aziz, S. Mohamad, S. Mustakim
A total of 86 Staphylococcus epidermidis strains were isolated from patients in Hospital Tengku Ampuan Rahimah, Klang, between December 2010 to March 2011. It was observed that 47% of these isolates were able to form biofilm with 14% displaying very strong biofilm formation, another 14% showed strong biofilm formation while 7% and 12% were moderate and weak biofilm producers respectively. Except for weak producers, the biofilm producing strains were further characterized for their susceptibility profiles against four antibiotics; gentamicin, erythromycin, oxacillin and rifampicin. Highest resistance pattern was observed in oxacillin where 97% of the S. epidermidis strains were found to be resistant to this antibiotic while 77% and 70% of the strains were resistant to erythromycin and gentamicin respectively. Rifampicin was found to be most effective against S. epidermidis where resistance was observed in only 40% of the isolates. In addition, more than 30% of these isolates displayed multi resistant to all four antibiotics tested.
{"title":"Biofilm formation and susceptibility towards antimicrobial agents in local clinical isolates of staphylococcus epidermidis","authors":"A. Abdul-Aziz, S. Mohamad, S. Mustakim","doi":"10.1109/CHUSER.2012.6504441","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504441","url":null,"abstract":"A total of 86 Staphylococcus epidermidis strains were isolated from patients in Hospital Tengku Ampuan Rahimah, Klang, between December 2010 to March 2011. It was observed that 47% of these isolates were able to form biofilm with 14% displaying very strong biofilm formation, another 14% showed strong biofilm formation while 7% and 12% were moderate and weak biofilm producers respectively. Except for weak producers, the biofilm producing strains were further characterized for their susceptibility profiles against four antibiotics; gentamicin, erythromycin, oxacillin and rifampicin. Highest resistance pattern was observed in oxacillin where 97% of the S. epidermidis strains were found to be resistant to this antibiotic while 77% and 70% of the strains were resistant to erythromycin and gentamicin respectively. Rifampicin was found to be most effective against S. epidermidis where resistance was observed in only 40% of the isolates. In addition, more than 30% of these isolates displayed multi resistant to all four antibiotics tested.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130191245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504387
Z. Mahmud, N. Zaki, R. Subban, A. M. Ali, M. Yahya
The effects of addition of potassium hydroxide (KOH) as doping salt in 49 % poly (methyl methacrylate)-grafted-natural rubber (MG49) were investigated. The free standing polymer electrolyte films doped with various wt. %of KOH salt was prepared by solution cast technique. The interaction between polymer and salt was confirmed by Fourier Transform Infrared (FTIR) spectroscopy studies. Ionic conductivity of the electrolyte films were studied by AC Impedance Spectroscopy. The highest ionic conductivity value obtained for the solid polymer electrolyte (SPE) is ∼10−7 S cm−1 at 25 wt. % of KOH. The increase and decrease in ionic conductivity are coupled with ion association and dissociation phenomena. Plasticized electrolyte film with 50 wt. % of PC exhibited an ionic conductivity of one order higher than the unplasticized film. The effect of ion associations is investigated and found to be closely related to the glass transition temperature (Tg) value of the film, in which decreases with the addition of propylene carbonate (PC) plasticizer.
研究了添加氢氧化钾(KOH)作为掺杂盐对49%聚甲基丙烯酸甲酯接枝天然橡胶(MG49)的影响。采用溶液浇铸法制备了掺杂不同质量分数的KOH盐的独立聚合物电解质薄膜。通过傅里叶变换红外光谱(FTIR)研究证实了聚合物与盐的相互作用。用交流阻抗谱法研究了电解质膜的离子电导率。固体聚合物电解质(SPE)在25 wt. %的KOH下获得的最高离子电导率值为~ 10−7 S cm−1。离子电导率的增加和减少与离子缔合和解离现象相耦合。添加PC量为50%的塑化电解质膜的离子电导率比未塑化膜高一个数量级。研究了离子结合力对薄膜玻璃化转变温度(Tg)的影响，发现其与薄膜玻璃化转变温度(Tg)值密切相关，Tg值随着碳酸丙烯酯(PC)增塑剂的加入而降低。
{"title":"MG49-KOH-PC alkaline gel polymer electrolytes membrane for supercapacitors","authors":"Z. Mahmud, N. Zaki, R. Subban, A. M. Ali, M. Yahya","doi":"10.1109/CHUSER.2012.6504387","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504387","url":null,"abstract":"The effects of addition of potassium hydroxide (KOH) as doping salt in 49 % poly (methyl methacrylate)-grafted-natural rubber (MG49) were investigated. The free standing polymer electrolyte films doped with various wt. %of KOH salt was prepared by solution cast technique. The interaction between polymer and salt was confirmed by Fourier Transform Infrared (FTIR) spectroscopy studies. Ionic conductivity of the electrolyte films were studied by AC Impedance Spectroscopy. The highest ionic conductivity value obtained for the solid polymer electrolyte (SPE) is ∼10−7 S cm−1 at 25 wt. % of KOH. The increase and decrease in ionic conductivity are coupled with ion association and dissociation phenomena. Plasticized electrolyte film with 50 wt. % of PC exhibited an ionic conductivity of one order higher than the unplasticized film. The effect of ion associations is investigated and found to be closely related to the glass transition temperature (Tg) value of the film, in which decreases with the addition of propylene carbonate (PC) plasticizer.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127611819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/CHUSER.2012.6504411
Siti Zulaikha Suhaili, U. S. Jais
It is well known that titanium dioxide photocatalyst can only be effectively activated by ultraviolet light due to its high band gap energy and therefore it is very essential to reduce the band gap energy by shifting the absorption wavelength to the visible region. Research has shown that doping TiO2 with metallic ions revealed promising results. In this study TiO2 was doped with cerium and the powder was prepared by sol-gel method and was characterized by X-ray diffraction (XRD), UV/Vis diffused reflectance spectroscopy (DRS) and scanning electron microscope (SEM). The photocatalytic activity under visible light was evaluated by photocatalytic degradation of methylene blue in water using UV/Vis spectrophotometer. Findings indicated that higher Ce3+ content resulted in shifting of absorption edge to longer wavelength which consequently lowered the band gap energy. At 1.0 wt% Ce-doped TiO2, offered lowest band gap at 2.64 eV and thereby the best photocatalytic activity was achieved. At this cerium content doping, the recombination of photo-induced electron and holes could be effectively inhibited.
{"title":"Improved visible light photocatalytic activity of TiO2 nano powder by Ce3+ doping","authors":"Siti Zulaikha Suhaili, U. S. Jais","doi":"10.1109/CHUSER.2012.6504411","DOIUrl":"https://doi.org/10.1109/CHUSER.2012.6504411","url":null,"abstract":"It is well known that titanium dioxide photocatalyst can only be effectively activated by ultraviolet light due to its high band gap energy and therefore it is very essential to reduce the band gap energy by shifting the absorption wavelength to the visible region. Research has shown that doping TiO2 with metallic ions revealed promising results. In this study TiO2 was doped with cerium and the powder was prepared by sol-gel method and was characterized by X-ray diffraction (XRD), UV/Vis diffused reflectance spectroscopy (DRS) and scanning electron microscope (SEM). The photocatalytic activity under visible light was evaluated by photocatalytic degradation of methylene blue in water using UV/Vis spectrophotometer. Findings indicated that higher Ce3+ content resulted in shifting of absorption edge to longer wavelength which consequently lowered the band gap energy. At 1.0 wt% Ce-doped TiO2, offered lowest band gap at 2.64 eV and thereby the best photocatalytic activity was achieved. At this cerium content doping, the recombination of photo-induced electron and holes could be effectively inhibited.","PeriodicalId":444674,"journal":{"name":"2012 IEEE Colloquium on Humanities, Science and Engineering (CHUSER)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121029779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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