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Empirical investigation to explore potential gains from the amalgamation of phase changing materials(PCms)and wood shavings

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能源与人工环境(英文) 2021年第3期2卷 315-326页

作者： Adham m.mohammed Amira Elnokaly abdel monteleb m.Aly Department of Architecture Faculty of EngineeringUniversity of AssuitEgypt School of Architecture and the Built Environment University of LincolnUK

The reduction of gained heat,heat peak shifting,and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation *** cannot be overstated that these fac-tors,in addition to others,govern the performance of such systems thus their effect on indoor ambient *** effect of such systems extends also to Heating,Ventilation and Air-conditioning(HVAC)systems that are set up to operate optimally in certain *** literature shows that PCms and natural materials such as wood-shavings can provide efficient passive insulation for buildings,it is evident that such approaches utilise methods that are of a degree of intricacy which require specialist knowledge and complex techniques,such as micro-encapsulation for *** technical and economic aspects in mind,an amalgam of PCm and wood-shavings has been created to be utilised as a feasible thermal *** amalgamation was performed in the simplest of methods,through submerging the wood shavings in *** experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated *** analysis revealed that no significant thermal gains would be expected from such ***,a significant reduction in the total weight of the insulation system would be achieved that,in this case,shown to be up to 20.94%.Thus,further reducing possible strains on structural elements due to the application of insulation on *** can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are *** addition,cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCms.

关键词： PCms Heat peak Heat peak shift Thermal performance Wood shavings By-products

Brushless Doubly-Fed Induction machine as a Variable Frequency Transformer

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Journal of Energy and Power Engineering 2013年第1期7卷 110-117页

作者： ayman abdel-Khalik Ahmed Elserougi Ahmed massoud Shehab Ahmed Electrical Engineering Department Alexandria University Alexandria 21544 Egypt Electrical Engineering Department Qatar University Doha 2713 Qatar Electrical and Computer Engineering Department Texas A & M University at Qatar Doha 23874 Qatar

VFT （variable frequency transformer） has been recently used as art alternative to HVDC （high voltage direct current） to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIm （doubly-fed induction machine） where the machine torque controls the power flow from stator to rotor and vice versa. The main disadvantage of this VFT is the slip rings and brushes required for the rotor circuit, especially in bulk power transmission. The BDFm （brushless doubly-fed machine） with nested cage rotor machine is proved to be a comparable alternative to conventional DFIm in many applications with the advantage that all windings being in the stator frame with fixed output terminals. In this paper, the BDFm is used as a BVFT （brushless variable frequency transformer）. A prototype machine is designed and simulated to verify the system validity.

关键词： Variable frequency transformer brushless doubly-fed machines AC machines induction machine.

Stem cells:Sources, and regenerative therapies in dental research and practice

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World Journal of Stem Cells 2015年第7期7卷 1047-1053页

作者： Lobna abdel aziz Aly Oral and maxillofacial Surgery Faculty of DentistryFuture University

Stem cells are considered to be among the principle scientific breakthroughs of the twentieth century for the future of medicine, and considered to be an important weapon to fight against diseases, particularly those that have resisted the efforts of science for a long time. Human dental tissues have limited potentials to regenerate but the discovery of dental stem cells have developed new and surprising scenario in regenerative dentistry. Stem cell treatments are one example of thepossibility using adult cells sourced from patients' own bodies' means that it can be expected that in the near future such treatments may become routine at dental practices. The hope is that it will become possible to regenerate bone and dental tissues including the periodontal ligament, dental pulp and enamel, and that the creation of new teeth may also become feasible. In view of this possibility of achieving restoration with regenerative medicine, it can be considered that a new era of dentistry is beginning. Thus the aim of this review is to give dental professionals a brief overview of different stem cells sources and the latest findings and their implications for improving oral health and treating certain conditions of the human mouth and face.

关键词： Stem cells Regeneration Dental research

Detection of Salmonella typhimurium in retail chicken meat and chicken giblets

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Asian Pacific Journal of Tropical Biomedicine 2013年第9期3卷 678-681页

作者： Doaa m Abd El-aziz Department of Food Hygiene Faculty of Veterinary MedicineAssiut University

Objective:To detect Salmonella typhimurium(***),one of the most frequently isolated serovars from food borne outbreaks throughout the world,in retail raw chicken meat and ***:One hundred samples of retail raw chicken meat and giblets(Liver,heart and gizzard)which were collected from Assiut city markets for detection of the organism and by using Duplex PCR amplification of DNA using rfbj andfliC ***:*** was detected at rate of 44%,40%and 48%in chicken meat,liver and heart,respectively,but not detected in ***:The results showed high incidence of *** in the examined samples and greater emphasis should be applied on prevention and control of contamination during processing for reducing food-borne risks to consumers.

关键词： Salmonella typhimurium Chicken meat Duplex PCR

Geology and mineral Chemistry of Uranium-and Thorium-bearing minerals in Rare-metal(NYF)Pegmatites of Um Solimate,South Eastern Desert,Egypt

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Acta Geologica Sinica(English Edition) 2021年第5期95卷 1568-1582页

作者： mohamed A.ALI Ahmed E.abdel GAWAD mohamed m.GHONEIm Nuclear materials Authority 530 El-MaadiCairoEgypt

The garnet muscovite granitic pegmatite of Um Solimate,in southern Egypt,represents a promising asset for strategic and economic metals,especially Bi-Ni-Ag-Nb-Ta as well as U and *** ore bodies occur as large masses,pockets and/or veins of very coarse-grained pegmatites,which consist mainly of K-feldspar,quartz and albite with subordinate muscovite,garnet,and *** data revealed that e U-and e Th-contents of the pegmatites reach up to 39 ppm and 82 ppm,*** studied pegmatites are enriched in primary U and Th minerals(uraninite,coffinite,thorianite and uranothorite)as well as Hf-rich zircon and monazite,which give rise to anomalous radioactive ***-tantalium-bearing minerals(***,microlite and uranopyrochlore),xenotime,barite,galena,fluorite,and apatite are ubiquitous,and,consequently,the studied pegmatites belong tothe Niobium-Yttrium-Fluorine-type(NYF)*** noble metal mineralization includes argentite(Ag_(2)S),native Ni and Bi as well as bismite and *** addition,beryl and tourmaline are observed in pegmatites near the contact with metasediments and ultramafic *** observed compositional variations of Ta/(Ta+Nb)and mn/(mn+Fe)ratios in columbite(0.08-0.45 and 0.11-0.57,respectively)and Hf contents in zircon(3.54-6.46 wt%)may reflectan extreme degree of magmatic fractionation leading to formation of the pegmatite orebody.

关键词： radioactivity rare-metal mineralization pegmatites U/Th-bearing minerals Um Solimate Egypt

Flywheel Energy Storage System Based on Boost DC-AC Converter

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Journal of Energy and Power Engineering 2012年第11期6卷 1725-1732页

作者： Ahmed Elserougi ayman abdel-Khalil Ahmed massoud Shehab Ahmed Electrical Engineering Department Alexandria University Alexandria 21544 Egypt Electrical Engineering Department Qatar University Doha 2713 Qatar Electrical and Computer Engineering Department Texas A & M University at Qatar Doha 23874 Qatar

To extend the operating speed range of a conventional configuration of FESS （flywheel energy storage system）, an additional DC-DC boost converter is required between the machine and grid side converters to regulate the output voltage. This paper presents a new FESS based on three-phase boost inverter topology. The proposed system facilitates voltage boost capability directly in a single-stage. The main advantage of the three-phase boost inverter is the deployment of only six switches and undersized passive elements to obtain a boosted AC output voltage weighed against the input DC supply. In this paper, FESS based on boost inverter topology is modeled and simulated using mATLAB/S1mULINK. An experimental setup has been built for the three-phase boost inverter to present its boosting capability. The simulation and experimental results sustain the proposed configuration.

关键词： Boost converter flywheel energy storage system FESS.

Rare earth oxides doped NiO/γ-Al_2O_3 catalyst for oxidative dehydrogenation of cyclohexane

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Journal of Rare Earths 2015年第6期33卷 611-618页

作者： Hany m.abdelD ayem m.Faiz Hesham S.abdel-Samad Salah A.Hassan Center of Research Excellence in Petroleum Refining & Petrochemicals (CoR E-PRP) King Fahd University of Petroleum & Minerals Chemistry Department College of Science King Faisal University Chemistry Department Faculty of Science Ain Shams University Surface Science Laboratory Physics Department King Fahd University of Petroleum &Minerals Department of Basic Sciences and Technology Community College Taibah University

The effect of rare earth oxides （RE=Ce, La, Gd, and Dy） doping of alumina support in NiO/7-A1203 system was investi- gated on its catalytic performance in oxidative dehydrogenation （ODH） of cyclohexane. The physicochemical properties of various samples were followed up through N2 physisorption, temperature programmed reduction （H2-TPR）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and potentiometric acid-base titration techniques. In the parent NiO/y-A1203 catalyst, Ni species were found to be strongly interacted with alumina surface. Addition of rare earth dopants to ）＇-A1203 in the catalyst system affected the nickel-alumina interaction and resulted in significant modifications in the catalytic performances in the ODH reaction. The results re- vealed the beneficial role of both La203 and Gd2Os doping in enhancing the ODH catalytic activity and selectivity to cyclohexene. H2-TPR and XPS results indicated that majority of Ni species in NiO/La203 modified T-A1203 were more weakly interacted with La203 and alumina whereas both NiO like species and nickel aluminate were present on the surface. Doping with cerium or dyspro- sium increased the nickel-support interaction and led to a decrease in surface nickel concentration. In case of doping with Ce, surface concentration of cerium oxide was higher than those of the other RE oxides; the doped catalyst reached its steady state activity faster than the other catalysts. The acid-base results suggested that RE metals were interacted most likely with acidic surface hydroxyl groups. The degree of nickel-alumina interaction decreased in the following order： LaAI〉GdAI〉CeAI〉DyA1.

关键词： nickel oxide rare-earth oxides doping Ni-A1203 interaction surface acidity oxidative dehydrogenation cyclohexane rare earths

magnetic Gearbox with an Electric Power Output Port and Fixed Speed Ratio for Wind Energy Applications

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Journal of Energy and Power Engineering 2013年第6期7卷 1141-1149页

作者： ayman abdel-Khalik Shehab Ahmed Ahmed massoud Ahmed Elserougi Electrical Engineering Department Alexandria University Alexandria 21544 Egypt Electrical and Computer Engineering Department Texas A&M University at Qatar Doha 23874 Qatar Electrical EngineeringDepartment Qatar University Doha 2713 Qatar

mechanical gearboxes are typically employed with doubly-fed induction generatur-based wind turbines. The main drawback of this solution is the gearbox＇s reliability and maintenance. Using magnetic gearbox in conjunction with the doubly-fed induction generator is an emerging alternative being promoted by the research community which maintains the reduced size doubly-fed machine and overcomes the mechanical gearbox problems reported by field experience. This paper proposes a novel magnetic gearbox configuration in which a conventional planetary magnetic gearbox is equipped with n-phase coils fitted around the ferromagnetic pole-pieces to extract output electrical power. The turbine mechanical power is thus divided into mechanical power to drive the electrical generator and extra electrical power that can be diverted into a storage system to perform the power leveling function. The proposed configuration can also be used to freely modify the power-speed characteristic as seen by the electrical generator, a highly needed feature for grid frequency support.

关键词： Gearbox magnetic planetary gear modular winding permanent magnets wind energy finite elements AC machines.

Chemical composition of the Tertiary black shales of West Sabah, East malaysia

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Chinese Journal Of Geochemistry 2008年第1期27卷 28-35页

作者： Amer m. Burgan Che aziz Ali Sanudin Hj Tahir School of Environmental and Natural Resources Department of Geology Faculty of Science and Technology University Kebangsaan Malaysia 43600 UKM Bangi Selangor Geology Program School of Science and Technology University Malaysia Sabah 88999 Kota Kinabalu Sabah Malaysia Locked Bag 2073

The X-ray fluorescence and ICP methods were used to analyze 60 outcrop samples of black shale, of which 15 were collected from Belait, 15 from the Setap Shale, 15 from Temburong, and 15 from the Trusmadi for- mations. The average compositions of the shales from the study area are 64.62%, 63.95%, 62.32%, 63.84% SiO2, 1.84%, 2.14%, 2.04%, 1.99% mgO, 2.55%, 3.12%, 2.89%, 2.72% K2O, 0.32%, 0.30%, 0.32%, 0.53% CaO, 5.86%, 6.06%, 7.14%, 6.60% Fe2O3, 207×10-6, 180×10-6, 213×10-6, 200×10-6 Rb, and 56×10-6, 49×10-6, 50×10-6, 32×10-6 Sr for the Setap Shale, Temburong, Belait and Trusmadi samples, respectively. The high Rb/Sr ratios of 3.8, 3.7, 4.2, and 6.1 are attributed to the lowest contents of Sr due to reducing conditions prevailing. The high Rb/K ratio sug- gests either brackish marine or rapid deposition that prevented equilibrium between Rb and K in the shales and ma- rine waters.

关键词：化合物页岩第三纪马来群岛