Totally found 1529 items.

  • [会议] Compressive Strength of Dental E-Glass Microfiber-Reinforced Composite Resin in Mouthwash Immersion
    Fiber-reinforced composite resin (FRC) is gaining popularity as dental filling material. In the oral cavity, it will contact with the oral environment including oral cleansing agents. This research was aimed to determine the effect of mouthwash on the compressive strength of FRC. The materials used were E-glass FRC (EverX Posterior, GC Corp, Japan), alcohol mouthwash (Original Listerine, Johnson&Johnson, Indonesia), alcohol-free mouthwash (Listerine Cool Mint Zero, Johnson&Johnson, Indonesia). Forty-five FRCs were made in cylindrical shapes. Specimens were divided into 2 groups of mouthwash immersion: alcohol and alcohol-free mouthwash. The groups were sub-grouped by 0, 6, 12, and 24 h immersion. Samples were recorded for compressive strength by Universal Testing Machine. The data were analyzed by ANOVA. The result of compressive strength values (MPa) were (alcohol mouthwash): 293.59±30.54 (0 h), 284.43±46.91 (6 h), 268.71±44.66 (12 h), 252.19±31.49 (24 h); (alcohol-free mouthwash): 294.12±28.17 (0 h), 287.30±35.56 (6 h), 273.32±41.94 (12 h), 260.82±40.67 (24 h). Statistical analysis revealed there was no significant influence of mouthwash type (alcohol or alcohol-free mouthwash), immersion duration (0, 6, 12, 24 h), and combination of mouthwash type and immersion duration (p>0.05) to the compressive strength of FRCs. The conclusions were the mouthwash types, immersion duration, and combination of mouthwash type and immersion duration did not influence the compressive strength of E-glass FRC.
    关键词: E-glass microfiber-reinforced composite;mouthwash;compressive strength
  • [会议] PREPARATION OF PVA-BASED CARBON NANOFIBERS AND THEIR ELECTROCHEMICAL PROPERTIES
    Poly vinyl alcohol(PVA)is a material generally used in glue.To use thermoplastic resin for a carbon material has not been focused due to its low carbonization yield.However,it has been reported that the carbonization yield is improved up to about 30% by pretreatment with iodine vapor1.Since PVA is a water-soluble polymer and easily forms a mixture with other water-soluble substances,it is likely to provide environmental friendly CNF preparation method.In this study,PVA nanofibers were prepared by electrospinning from PVA aqueous solution containing potassium iodine(KI),and carbon nanofibers(CNFs)were prepared without iodine vapor pretreatment.Electrochemical characteristics of CNF were evaluated for an electric double-layer capacitor(EDLC).This study gives ecofriendly CNF preparation method.
    关键词: -
  • [会议] PREPARATION OF PVA-BASED CARBON NANOFIBERS AND THEIR ELECTROCHEMICAL PROPERTIES
    Poly vinyl alcohol(PVA)is a material generally used in glue.To use thermoplastic resin for a carbon material has not been focused due to its low carbonization yield.However,it has been reported that the carbonization yield is improved up to about 30% by pretreatment with iodine vapor1.Since PVA is a water-soluble polymer and easily forms a mixture with other water-soluble substances,it is likely to provide environmental friendly CNF preparation method.In this study,PVA nanofibers were prepared by electrospinning from PVA aqueous solution containing potassium iodine(KI),and carbon nanofibers(CNFs)were prepared without iodine vapor pretreatment.Electrochemical characteristics of CNF were evaluated for an electric double-layer capacitor(EDLC).This study gives ecofriendly CNF preparation method.
    关键词: -
  • [会议] Alkali absorption and durability studies on CFRP laminated composites
    Fiber Reinforced Plastics (FRP) are widely used in marine, aeronautical, automotive, space applications due to their corrosive resistance and low cost to performance. The main aim of this research was to examine the impact of alkali absorption and durability in the Carbon/Epoxy, Carbon/Vinylester, and Carbon/Isopolyester composites immersed in 13.59 pH alkaline solutions for a maximum of 25 days at 27℃ (room temperature) and 65℃. Epoxy, vinyl-ester and Isoployester resin are selected as a matrix material and Poly-acrylonitrile-based Carbon fiber of 200 gsm fabrics is chosen as reinforcement and hand lay-up process is used for fabrication in the ratio of 35: 65 respectively and cured at room temperature with applied pressure using hydraulic press for 24 hrs. Solution of alkali was prepared and specimens were subjected to alkali solution. The moisture absorption was calculated on the basis of rate of moisture for every 5days interval and rate of diffusion coefficient (m2/sec) were calculated. Similarly durability studies (UTS, ILSS and FS) are conducted at 27℃ and 65℃. Characterization of the fractured area was done using a scanning microscope. The obtained result rate of moisture absorption in case of neat casting and CFRP specimen shows the maximum alkali absorption in Iso-polyester / carbon whereas the minimum absorption was shown in vinyl ester/carbon specimens at RT and at 65℃ over a period of 25days. At room temperature and 65℃ the diffusion coefficient (D) was found and identified higher value for Iso-polyester/carbon and low for vinyl ester/carbon this is because Iso-polyester are distributed along the main chain, which makes easily available for reaction but in vinylesters the ester functional groups acts as a shield by methyl groups which restrict the easy absorption. Reduce in percentage in mechanical properties is due to Alkali absorption in terms of reduced degradation values in UTS, Flexural Strength and ILSS samples, carbon / epoxy showed supremacy over vinylester / carbon and iso-polyester / carbon. Scanning electron microscopy images show the embrittlement and micro-cracks on surface due to exposure to the alkali environments, matrix bonded to fiber are hardly identified as the temperature increases.
    关键词: -
  • [会议] Design and Fabrication of Biodegradable Microneedle Using 3D Rapid Prototyping Printer
    Microneedle is known as transdermal drug delivery (TDD) devices that uses to deliver biological fluid into veins and needle that use to tear skin to collect blood sample. It involves with various parameters and designs. This device gain attention as its benefit can eliminate pain and more convenient compared to intravenous injection due to its micron size. Typically, microneedle is fabricated using MEMS technology. However, this technology requires few processes such as deposition, etching and moulding, as well as consume much times. This paper presents a work of design and fabrication of solid microneedle using 3D rapid prototype printing. A few types of microneedles are designed and they are analysed in terms of stress and force characteristics. Also, it will study the ability of a few materials to withstand stress while force exerted on it. The selected materials are polyvinyl alcohol (PVA), polylactic acid (PLA), polyester resin and acrylonitrile butadiene styrene (ABS). The results show that PVA has the highest ability to withstand force compared other materials. As conclusion, the design and fabrication of microneedle using 3D rapid prototyping printer is succeed using PVA material and real post-analysis can be conducted to test the capability for medical practice.
    关键词: -
  • [会议] BINDING STUDIES OF ANTIPSYCHOTIC DRUG RISPERIDONE WITH β-LACTOGLOBULIN USING FLUORIMETRY AND MOLECULAR MODELLING
    Risperidone(RIS)is a highly potent,biopharmaceutic classification system(BCS)class II drug which is often used to treat schizophrenia.1'2 The main drawbacks of RIS are that it is practically insoluble in water,has a bitter taste and also shows photoinstability.2"4 Several studies to improve these drawbacks are as follows:Taste masked orodispersible tablets(ODT)of RIS-cation exchange resin complexes,in ratios 1:1 for RIS:Kyron T-104,1:2 for RIS-lndion 204 complex,1:4 for RIS-Amberlite IRP64 resin and complexing RIS with cetyl alcohol in 2:1 ratios were used for masking bitter taste of RIS.Nanocrystal-based drug delivery system of RIS has shown potential for enhancing the apparent solubility of RIS using nanonization technique.Researchers have reported different approaches for enhancement of water solubility of RIS including solid dispersion,self-nanoemulsifying powder and co-solvent.Sterically stabilized nanosuspension of RIS has been prepared using high amount of surfactant which enhanced oral bioavailability of RIS by two fold.However,none of them explored the food based protein to modulate the properties of RIS.
    关键词: -
  • [会议] New Approach to Enhance Extra-Heavy Oil Recovery Through Recreation of Foamy Oil Behavior
    Cold extra-heavy oil production from the Orinoco Heavy Oil Belt reservoirs in Venezuela presents foamy oil behavior and has shown a primary recovery factor of only 8-12%.Produced methane reinjection process in huff-n-puff mode has been proved to be inefficient,because methane is difficult to dissolve in but easy to evolve out of the oil phase during traditional cyclic gas injection process.Meanwhile,steam injection nowadays is not an economically attractive follow-up candidate for improving the recovery due to low oil price.Thus,alternative non-thermal EOR approaches have drawn increasing attention.Laboratory tests on the effects of asphaltene and resin on foamability,and unconventional PVT behavior were conducted for typical foamy oil sample from Block M in the eastern Heavy Oil Belt.Based on the understandings,a non-thermal process to recreate foamy oil behavior was proposed through sequential injection of compound fluid slugs,comprising of light hydrocarbon solvent,gas,and foaming agents promoting the regeneration of foamy oil.Then,injected multi-slug formula was screened and evaluated through experiments of foamability,2D visualized micro-flow,ID sand pack flooding,and etc.Results showed that the presence of asphaltene enhances the foamability,and foamy oil displacement efficiency increased with increasing solution gas-oil ratio,which laid a theoretical foundation for the feasibility of above-mentioned foamy oil recreation process following cold production depletion.The screened slugs are naphtha,methane and foaming agent E plus foam stabilizer HKS respectively.In a huff-n-puff process,those slugs are designed to be injected in sequence during the injection stage.The firstly injected naphtha,as preposi-tioned solvent slug,can reduce degassed heavy oil viscosity,and promote the dissolution of the secondly injected methane;and then the finally injected foam agents can defer the separation of gas from the oil phase,and helps to restore the fluid flow into foamy oil behavior.2D visualized micro-flow experiments showed that the process presented pseudo-single phase flow behavior.Following up the primary depletion,an incremental oil displacement efficiency of 30 percentage points could be achieved through 5 cycles of cyclic foamy oil recreation process.This study provided a new post-cold EOR approach for foamy oil reservoirs.
    关键词: Extra-heavy oil;Cold production;Foamy oil recreation-Foaming agent;EOR
  • [会议] The Properties of 0.5BZT - 0.5BCT Piezoelectric Ceramic from Gel Casting Process by Using Ethylene Glycol Diglycidyl Ether (EGDGE) Epoxy Resin as a Gelling Agent
    This research is concerned with properties of 0.5BZT - 0.5BCT through a water based gel casting process by using Ethylene Glycol Diglycidyl Ether (EGDGE) epoxy resin as a gelling agent. A solution of an ammonium salt of an acrylic polymer in water (NH_4PAA) was used as an additive in order to make the dispersion of the powders easier and provide better stability of the slurry and dispersant. The results were found that viscosity of the 0.5BZT - 0.5BCT with EGDGE epoxy resin was minimised by the addition of 1.6 wt% of dispersant based on the dried powder weight. The highest green strength of around 25 MPa was achieved at 30 wt% EGDGE epoxy resin content and 44 vol% solids loading. The gel casting samples were studied at sintering temperatures between 1300 - 1500 °C. The highest values of piezoelectric and dielectric properties corresponded to 0.5BZT - 0.5BCT gel casting samples fabricated with a gel casting slurry incorporating 30 wt% EGDGE epoxy resin content, 44 vol% solids loading and sintered at 1500 °C, with d33 and εr values of 310 pC/N and 2515, respectively.
    关键词: BCZT;Piezoelectric;Dielectric;Relative Permittivity;EGDGE;Epoxy Resin;Gel Casting
  • [会议] The Properties of 0.5BZT - 0.5BCT Piezoelectric Ceramic from Gel Casting Process by Using Ethylene Glycol Diglycidyl Ether (EGDGE) Epoxy Resin as a Gelling Agent
    This research is concerned with properties of 0.5BZT - 0.5BCT through a water based gel casting process by using Ethylene Glycol Diglycidyl Ether (EGDGE) epoxy resin as a gelling agent. A solution of an ammonium salt of an acrylic polymer in water (NH_4PAA) was used as an additive in order to make the dispersion of the powders easier and provide better stability of the slurry and dispersant. The results were found that viscosity of the 0.5BZT - 0.5BCT with EGDGE epoxy resin was minimised by the addition of 1.6 wt% of dispersant based on the dried powder weight. The highest green strength of around 25 MPa was achieved at 30 wt% EGDGE epoxy resin content and 44 vol% solids loading. The gel casting samples were studied at sintering temperatures between 1300 - 1500 °C. The highest values of piezoelectric and dielectric properties corresponded to 0.5BZT - 0.5BCT gel casting samples fabricated with a gel casting slurry incorporating 30 wt% EGDGE epoxy resin content, 44 vol% solids loading and sintered at 1500 °C, with d33 and εr values of 310 pC/N and 2515, respectively.
    关键词: BCZT;Piezoelectric;Dielectric;Relative Permittivity;EGDGE;Epoxy Resin;Gel Casting
  • [会议] Materials,Well Designs and Numerical Simulations for the Construction of aLow Loss Zone for Radiofrequency Downhole Heating
    Downhole RF heating continues to be the interest of the petroleum industry because of its advantages overconventional forms of heating.Previous results have shown that without a low-loss dielectric zone(LLZ)around the downhole RF emitter,none of the available linear dipole antennas can work efficiently,and mostof the energy is absorbed preferentially in a few meter radius around the radiating well and will not penetratesubstantially into the reservoir.To circumvent this problem,low-dielectric materials were proposed,whichare composed of a solid mixed with an appropriate binder.These materials were selected to have lowdielectric properties so that the RF absorption is minimized,and at the same time,low porosity to preventwater invasion during the RF heating operation.Four solids,Ottawa sand,solvent deasphalted tar,Poly(p-phenylene sulfide)(PPS)and Polyether ether ketone(PEEK)and four binders(polydicyclo pentadiene(DCPD)and phenol-formaldehyde resins(Novolac),a C-Class cement slurry,and a foamed cement)wereevaluated by measuring their dielectric properties(dielectric constant and loss tangent)in the frequencyrange 1-2000 kHz and temperatures between 25-200℃.All four solids have low RF absorption as well aslow porosity(<1%),and those values did not change significantly with temperature.Also,smaller dielectricproperties were found for DCPD and Novolac than those found for the cement materials,and the DCPDbinder has a dielectric constant almost half and a loss tangent one order of magnitude lower than thosemeasured for the Novolac resin.Three different designs for the construction of LLZ were considered,whichincluded underreaming the oil well,squeezing a solid-containing binder downhole,and creating a casing-less completion.Numerical simulations show that the use of a low-loss zone around the central emitterleads to a very much improved energy and temperature distribution,and higher penetrations(~12 m)thanthe case without it.
    关键词: -
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