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Study of Hydrogen Adsorption on Pt/WO_3-ZrO_2 through Pt Sites

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Journal of Natural Gas Chemistry 2007年第3期16卷 252-257页

作者： Sugeng Triwahyono aishah Abdul Jalil Hideshi Hattori Ibnu Sina Institute for Fundamental Science Studies Faculty of SciencesUniversiti Teknologi Malaysia81310 UTM SkudaiJohorMalaysia Faculty of Chemical & Natural Resources Engineering Universiti Teknologi Malaysia81310 UTM SkudaiJohorMalaysia Center for Advanced Research of Energy Technology Hokkaido UniversityNishi 5Kita 8Sapporo060-0808Japan

The rate determining step and the energy barrier involved in hydrogen adsorption on Pt/WO3- ZrO2 were studied based on the assumption that the hydrogen adsorption occurs only through Pt sites. The rate of hydrogen adsorption on Pt/WOa-ZrO2 was measured in the adsorption temperature range of 323-573 K and an initial hydrogen pressure of 50 Torr. The rates of hydrogen uptake were very high for the initial few minutes and the adsorption continued for more than 5 h below 523 K. The hydrogen uptake far exceeded the H/Pt ratio of unity for all adsorption temperatures, indicating that the adsorption of hydrogen involved the dissociative adsorption of hydrogen on Pt sites to form hydrogen atoms, the spillover of hydrogen atoms onto the surface of the WO3-ZrO2 catalyst, the diffusion of spiltover hydrogen atom over the surface of the WO3-ZrO2 catalyst, and the formation of protonic acid site originated from hydrogen atom by releasing an electron in which the electron may react with a second hydrogen atom to form a hydride near the Lewis acid site. The rate determining step was the spillover with the activation energy of 12.3 kJ/mol. The rate of hydrogen adsorption cannot be expressed by the rate equation based on the assumption that the rate determining step is the surface diffusion. The activity of Pt/WO3-ZrO2 was examined on n-heptane isomerization in which the increase of hydrogen partial pressure provided positive-effect on the conversion of n-heptane and negative-effect on the selectivity towards iso-heptane.

关键词： Pt/WO3-ZrO2 Pt sites hydrogen adsorption spillover n-heptane isomerization

The Effect of Sulfate Ion on the Isomerization of n-Butane to iso-Butane

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Journal of Natural Gas Chemistry 2006年第4期15卷 247-252页

作者： Sugeng Triwahyono Zalizawati Abdullah aishah Abdul Jalil Ibnu Sina Institute for Fundamental Science Studies Faculty of Chemical and Natural Resources Engineering Universiti Teknologi Malaysia 81310 SkudaiJohorMalaysia

The effect of sulfate ion （SO4^2-） loading on the properties of Pt/SO4^2-ZrO2 and on the catalytic isomerization of n-butane to/so-butane was studied. The catalyst was prepared by impregnation of Zr（OH）4 with H2SO4 and platinum solution followed by calcination at 600 ℃. Ammonia TPD and FT-IR were used to confirm the distribution of acid sites and the structure of the sulfate species. Nitrogen physisorption and X-ray diffraction were used to confirm the physical structures of Pt/SO4^2-ZrO2. XRD pattern showed that the presence of sulfate ion stabilized the metastable tetragonal phase of zirconia and hindered the transition of amorphous phase to monoclinic phase of zirconia. Ammonia TPD profiles indicated the distributions of weak and medium acid sites observed on 0.1 N and 1.0 N sulfate in the loaded catalysts. The addition of 2.0 N and 4.0 N sulfate ion generated strong acid site and decreased the weak and medium acid sites. However, the XRD results and the specific surface area of the catalysts indicated that the excessive amount of sulfate ion collapsed the structure of the catalyst. The catalysts showed high activity and stability for isomerization of n-butane to iso-butane at 200 ℃ under hydrogen atmosphere. The conversion of n-butane to iso-butane per specific surface area of the catalyst increased with the increasing amount of sulfate ion owing to the existence of the bidentate sulfate and/or polynucleic sulfate species （（ZrO）2SO2）, which acts as an active site for the isomerization.

关键词： sulfate ion strong acid site isomerization n-butane Zr Pt

Data-Driven Load Forecasting Using Machine Learning and Meteorological Data

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Computer Systems Science & Engineering 2023年第3期44卷 1973-1988页

作者： aishah Alrashidi Ali Mustafa Qamar Department of Computer Science College of ComputerQassim UniversityBuraydahSaudi Arabia

Electrical load forecasting is very crucial for electrical power systems’planning and *** electrical buildings’load demand and meteorological datasets may contain hidden patterns that are required to be investigated and studied to show their potential impact on load *** meteorological data are analyzed in this study through different data mining techniques aiming to predict the electrical load demand of a factory located in Riyadh,Saudi *** factory load and meteorological data used in this study are recorded hourly between 2016 and *** data are provided by King Abdullah City for Atomic and Renewable Energy and Saudi Electricity Company at a site located in *** applying the data pre-processing techniques to prepare the data,different machine learning algorithms,namely Artificial Neural Network and Support Vector Regression(SVR),are applied and compared to predict the factory *** addition,for the sake of selecting the optimal set of features,13 different combinations of features are investigated in this *** outcomes of this study emphasize selecting the optimal set of features as more features may add complexity to the learning ***,the SVR algorithm with six features provides the most accurate prediction values to predict the factory load.

关键词： Electricity load forecasting meteorological data machine learning feature selection modeling real-world problems predictive analytics

Methane to Liquid Hydrocarbons over Tungsten-ZSM-5 and Tungsten Loaded Cu/ZSM-5 Catalysts

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Journal of Natural Gas Chemistry 2006年第4期15卷 340-347页

作者： Didi Dwi Anggoro Nor aishah Saidina Amin Department of Chemical Engineering University of Diponegoro TembalangSemarang 50239Indonesia Faculty of Chemical and Natural Resources Engineering Universiti Teknologi MalaysiaJohor Bahru 81130Malaysia

Metal containing ZSM-5 can produce higher hydrocarbons in methane oxidation. Many researchers have studied the applicability of HZSM-5 and modify ZSM-5 for methane conversion to liquid hydrocarbons, but their research results still lead to low conversion, low selectivity and low heat resistance. The modified HZSM-5, by loading with tungsten （W）, could enhance its heat resistant performance, and the high reaction temperature （800 ℃） did not lead to a loss of the W component by sublimation. The loading of HZSM-5 with tungsten and copper （Cu） resulted in an increment in the methane conversion as well as CO2 and C5＋ selectivities. In contrast, CO, C2-3 and H2O selectivities were reduced. The process of converting methane to liquid hydrocarbons （C5＋） was dependent on the metal surface area and the acidity of the zeolite. High methane conversion and C5＋ selectivity, and low H20 selectivity are obtained over W/3.0Cu/HZSM.

关键词： methane liquid hydrocarbons HZSM-5 W-ZSM-5 W-Cu/ZSM-5

Comparative study on hash functions for lightweight blockchain in Internet of Things(IoT)

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Blockchain(Research and Applications) 2021年第4期2卷 49-55页

作者： aishah Alfrhan Tarek Moulahi Abdulatif Alabdulatif Department of Information Technology College of ComputerQassim UniversityBuraydah51013Saudi Arabia Department of Computer Science College of ComputerQassim UniversityBuraydah51013Saudi Arabia

Over the last few years,there has been a great interest in the Internet of Things(IoT).This is mainly because the IoT interacts directly with people's everyday lives in critical applications,such as in smart homes and healthcare *** devices typically have a resource-constrained architecture,rendering them vulnerable to ***,smart devices and stored data need to be secured through lightweight and energyefficient security solutions,which have been identified as the main challenge facing adoption of IoT *** address this problem,a disruptive technology(blockchain)has been foreseen by the industry and research community as being able to deliver secure,fast,reliable,and transparent solutions for IoT ***,this work investigates the adoption of lightweight blockchain technology,mainly as a method of securing IoT *** hashing plays a major role in creating a robust blockchain structure,we select a number of different hash techniques to be executed on a Raspberry Pi *** summation,this work provides a numerical study to evaluate the performance of well-known hash functions that can be used for lightweight blockchain-based IoT.

关键词： Lightweight blockchain Internet of Things(IoT) Hash Cybersecurity

Issues and challenges in diabetic neuropathy management:A narrative review

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World Journal of Diabetes 2023年第6期14卷 741-757页

作者： Che aishah Nazariah Ismail Department of Physiology School of Medical SciencesUniversity Sains Malaysia Health CampusKubang Kerian 16150KelantanMalaysia

Diabetic neuropathy(DN)is a devastating disorder with an increasing prevalence *** epidemic can pose a critical burden on individuals and communities,subsequently affecting the productivity and economic output of a *** more people living a sedentary lifestyle,the incidence of DN is escalating *** researchers have relentlessly worked on ways to combat this devastating *** efforts have given rise to a number of commercially available therapies that can alleviate the symptoms of ***,most of these therapies are only partially *** still,some are associated with unfavorable side *** narrative review aims to highlight current issues and challenges in the management of DN,especially from the perspective of molecular mechanisms that lead to its progression,with the hope of providing future direction in the management of *** improve the approaches to diabetic management,the suggested resolutions in the literature are also discussed in this *** review will provide an in-depth understanding of the causative mechanisms of DN,apart from the insights to improve the quality and strategic approaches to DN management.

关键词： Diabetic neuropathy Pathophysiology Diabetic management Diabetic medication

Screening of MgO- and CeO_2-Based Catalysts for Carbon Dioxide Oxidative Coupling of Methane to C_(2+) Hydrocarbons

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Journal of Natural Gas Chemistry 2004年第1期13卷 23-35页

作者： Istadi Nor aishah Saidina Amin Chemical Reaction Engineering Group(CREG) Faculty of Chemical and Natural Resources EngineeringUnivevsiti Teknologi MalaysiaUTM SkudaiJohor Bahru81310 Malaysia

The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively.

关键词： catalyst screening carbon dioxide oxidative coupling methane ternary metal oxide binary metal oxide MgO CeO2 C2+ hydrocarbons

Improved Performance of W/HZSM-5 Catalysts for Dehydroaromatization of Methane

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Journal of Natural Gas Chemistry 2004年第3期13卷 148-159页

作者： Nor aishah Saidina Amin Kusmiyati Department of Chemical Engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.Department of Chemical Engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.

The dehydroaramatization of methane over W-supported ZSM-5 with varying degrees of Li+ ion-exchanged catalysts was studied with and without oxygen at 1073 K and atmospheric pressure. Catalyst activity and stability were found to be influenced by the catalyst acidity related to Bronsted acid sites and by the presence of oxygen in the feed. The NH3-TPD and FTIR-pyridine results demonstrated that partially exchanged of H+ ions by Li+ into the W/HZSM-5 catalysts could be used to control the amount of strong acid sites on the catalyst surface. Without oxygen, the 3WHLi-Z (5:1) catalyst that has strong acid sites equal to nearly 74% of the original strong acid sites in the parent HZSM-5 exhibited the highest methane conversion and selectivity towards aromatics. However, the catalyst deactivated in a five hour period. In the presence of oxygen, the catalyst activity and stability could be improved further. The results of this study revealed that a suitable amount of strong Bronsted acid sites as well as oxygen addition in the feed increased the catalyst activity and stability. The 3WHLi-Z(5:1) catalyst exhibited improved performance in the dehydroaromatization of methane.

关键词： dehydroaromatization methane W-supported ZSM-5 partial ion exchange H+ ion Li ion catalyst activity catalyst stability catalyst acidity oxygen presence improved performance

Synthesis, Characterization and X-ray Structure of N-(4-bromobutanoyl-N'-(2-3-and 4-methylphenyl)thiourea

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Chinese Journal of Structural Chemistry 2015年第3期34卷 379-385页

作者： Hamza M Abosadiya Siti aishah Hasbullah Bohari M Yamin School of Chemical Sciences and Food Technology Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia

N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.

关键词： 4-bromobutyryl chloride, thiourea derivatives, X-ray structural study