Comparison between local-made and imported porous polyethylene orbital implant:a randomized controlled equivalence trial and multicenter study

AIM:To compare the exposure rate,infection rate,percentage of enhancement,and success rate between Medpor and the three-dimensional printed polyethylene(3DP-PE)orbital implant in a preliminary report.METHODS:This prospective,randomized,equivalence,controlled trial was conducted at two institutes.The equivalent margin was±10%.The sample size for the equivalence trial was 174 participants per group.Patients who were eligible for enucleations received either Medpor or 3DP-PE implants based on a randomized block of six.The surgeries were performed by five oculoplastic surgeons.The assessor and patients were masked.The magnetic resonance imaging(MRI)of the orbit was performed at least 6mo after operation and the fibrovascular ingrowth was analyzed using the Image J software.Follow-up continued at least 1y after surgery.The intention to treat and per protocol approaches were used.RESULTS:Totally 128 patients met the criteria in the report.Fifty Medpor and 553DP-PE cases completed the trial.The most common cause of blindness was trauma.The mean follow-up times of Medpor and 3DP-PE were 33 and 40mo respectively.The exposure rate was not statistically significant between two groups(6.0%and 7.3%),P<0.05,95%CI(-9.8%,+12.0%).The success rates were 94%(Medpor)and 92.7%(3DP-PE).No postoperative infection was reported.Nine patients had MRI tests and two had implant exposures with 66.3%enhancement at 75mo(Medpor)and 58%enhancement at 57mo(3DP-PE)postoperatively.CONCLUSION:There is no statistically significant difference in exposure rate and success rate between Medpor and 3DP-PE in enucleation in the report.However,we cannot conclude that they are equivalent in terms of the exposure rate and success rate because the 95%CI is wider than±10%.The infection rate is equivalent in both groups.

Preparation and characterization of ceramic materials with low thermal conductivity and high strength using high-calcium fly ash

High calcium-fly ash(HCFA)collected from the Mae Moh electricity generating plant in Thailand was utilized as a raw material for ceramic production.The main compositions of HCFA characterized by X-ray fluorescence mainly consisted of 28.55wt%SiO_(2),16.06wt%Al_(2)O_(3),23.40wt%CaO,and 17.03wt%Fe_(2)O_(3).Due to high proportion of calcareous and ferruginous contents,HCFA was used for replacing the potash feldspar in amounts of 10wt%-40wt%.The influence of substituting high-calcium fly ash(0-40wt%)and sintering temperatures(1000-1200℃)on physical,mechanical,and thermal properties of ceramic-based materials was investigated.The results showed that the in-corporation of HCFA in appropriate amounts could enhance the densification and the strength as well as reduce the thermal conductivity of ceramic samples.High proportion of calcareous and ferruginous constituents in fly ash promoted the vitrification behavior of ceramic samples.As a result,the densification was enhanced by liquid phase formation at optimum fly ash content and sintering temperature.In addition,these components also facilitated a more abundant mullite formation and consequently improved flexural strength of the ceramic samples.The op-timum ceramic properties were achieved with adding fly ash content between 10wt%-30wt%sintered at 1150-1200℃.At 1200℃,the max-imum flexural strength of ceramic-FA samples with adding fly ash 10wt%-30wt%(PSW-FA(10)-(30))was obtained in the range of 92.25-94.71 MPa when the water absorption reached almost zero(0.03%).In terms of thermal insulation materials,the increase in fly ash addi-tion had a positively effect on the thermal conductivity,due to the higher levels of porosity created by gas evolving from the inorganic decom-position reactions inside the ceramic-FA samples.The addition of 20wt%-40wt%high-calcium fly ash in ceramic samples sintered at 1150℃reduced the thermal conductivity to 14.78%-49.25%,while maintaining acceptable flexural strength values(~45.67-87.62 MPa).Based on these promising mechanical and thermal characteristics,it is feasible to utilize this high-calcium fly ash as an alternative raw material in clay compositions for manufacturing of ceramic tiles.

Effect of Process Parameters on Morphology and Grain Refinement Efficiency of TiAl_3 and TiB_2 in Alumimum Casting

This paper presents the effects of different process parameters in producing Al-STi-1B grain refiner,i.e.various sequences and reaction time,on grain refinement efficiency of aluminum castings.It was found that different process parameters resulted in different morphology and size distribution of TiAl-3 and TiB-2 in grain refiner. The experiment was carried out by adding KBF-4 and K-2TiF-6 to molten aluminum.The melting temperature was controlled at 800℃in an electric resistance furnace.Three different sequences of KBF-4 and K-2TiF-6 additions were applied,i.e.,adding KBF-4 before K-2TiF-6,adding K-2TiF-4 before KBF-4 and mixing both KBF-4 and K-2TiF-6 before adding to molten aluminum.Three different holding time at 1 min,30 min and 60 min were applied.The results showed that no significant difference of morphology and size distribution was found by varying three different sequences.Whereas,the different holding time provided major differences in both morphology and size distribution,which are technically expectable from diffusion and agglomeration between particles resulting in larger particle size and wider range of size distribution of TiAI3 and TiB2.If the reaction time was longer than 30 rain,morphology of both TiAl-3 and TiB-2 became too large.If the reaction time was too short,less reaction between TiAl-3 and TiB2 to form would be obtained.For grain refinement efficiency, it was found that mixing KBF-4 and K-2TiF-6 before adding to molten aluminum with a holding time of 30 min resulted in best grain refinement efficiency.

Effects of Heat Treatment on Hardness and Dry Wear Properties of a Semi-Solid Processed Fe-27 wt pct Cr-2.9 wt pct C Cast Iron

EfFects of heat treatments on hardness and dry wear properties of a semi-solid processed Fe-26.96 wt pct Cr- 2.91 wt pct C cast iron were studied. Heat treatments included tempering at 500℃, destabilisation at 1075℃ and destabilisation at 1075℃ plus tempering at 500℃, all followed by air cooling. Electron microscopy revealed that, in the as-cast condition, the primary proeutectic austenite was round in shape while the eutectic M7C3 carbide was found as radiating clusters mixed with directional clusters. Tempering did not change the microstructure significantly when observed by scanning or transmission electron microscopy. Destabilisation followed by air cooling led to a precipitation of secondary M23C6 carbide and a transformation of the primary austenite to martensite. Precipitation behaviour is comparable to that observed in the conventionally cast iron. Tempering after destabilisation resulted in a higher amount of secondary carbide precipitation within the tempered martensite in the eutectic structure. Vickers macrohardness and microhardness in the proeutectic zones were measured. Dry wear properties were tested by using a pin-on-disc method. The maximum hardness and the lowest dry wear rate were obtained from the destabilisation-plus-tempering heat treatment due to the precipitation of secondary carbides within the martensite matrix and a possible reduction in the retained austenite.

Effect of Anodization Parameters on Morphologies of TiO2 Nanotube Arrays and Their Surface Properties

This work presents the potentiostatic anodization study of titania nanotube array films fabricated in fluoride-based organic electrolytes including DEG （diethylene glycol） and EG （ethylene glycol）. The work focuses on the effect of important anodization parameters such as applied voltage, anodization time, and electrolyte type on nanotube morphologies and corresponding surface properties. Depending upon unique nanotube formation structures obtained from each anodizing electrolyte, wettability of the nanotube array layer has been determined by means of the contact angle measurement. The EG nanotube array films with close-packing cell orientation are found to show hydrophilic behavior. While the well separated DEG nanotube array films are found to exhibit hydrophobic behavior, with the characteristics of more discrete, wider cell separation obtained through manipulating the electrolyte conditions and the fabrication techniques offering considerable prospects for developing the superhydrophobic sample surface. Such formation structures observed for the DEG fabricated nanotube is believed to play a prominent role in determining the surface wettability of the anodized nanotube array film. The achieved result in this work is anticipated to pave the way to other relevant applications, where interfacial properties are critically concerned.

Effects of Substrate Temperature and Vacuum Annealing on Properties of ITO Films Prepared by Radio-Frquency Magnetron Sputtering

Indium tin oxide （ITO） films were prepared by rf magnetron sputtering under two conditions： （i） at substrate temperature Ts from room temperature （RT） to 350℃ （ii） with additional post-annealing in vacuum at 400℃ for 30 min in comparison of their crystalline structures, and electrical-optical properties of the films deposited. From the experimental results, it is found that, under the first condition, the crystalline structures and the electrical-optical properties of the films are improved with the increasing Ts. Under the other condition, i.e. with the additional post-annealing, the films exhibit higher degree of crystallinities and better electrical-optical properties. Under the two deposition conditions, inter-relation between electrical-optical properties and the crystalline structure is observed clearly. However, even under the same annealing condition, it is observed that improved properties of the films are different, depending on their deposition temperatures, which implies that an initial stage of the ITO film before annealing is an important factor for the film＇s properties improved after annealing. The resistivity of 2.33 × 10-4 Ω·cm can be achieved at Ts of 350℃after annealing.

Effect of weld line positions on the tensile deformation of two-component metal injection moulding

Knowledge of the mechanical properties of two-component parts is critical for engineering functionally graded components. In this study, mono-and two-component tensile test specimens were metal injection moulded. Three different weld line positions were generated in the two-component specimens. Linear shrinkage of the two-component specimens was greater than that of the mono-component specimens because the incompatibility of sintering shrinkage of both materials causes biaxial stresses and enhances sintering. The mechanical properties of 316L stainless steel were affected by the addition of a coloured pigment used to identify the weld line position after injection moulding. For the two-component specimens, the yield stress and ultimate tensile stress were similar to those of 316L stainless steel. Because 316L and 630(also known as 17-4PH) stainless steels were well-sintered at the interface, the mechanical properties of the weaker material(316L stainless steel) were dominant. However, the elongations of the two-component specimens were lower than those of the mono-component specimens. An interfacial zone with a microstructure that differed from those of the mono-material specimens was observed; its different microstructure was attributed to the gradual diffusion of nickel and copper.

Effect of Alloying Element Antimony on Macrostructural and Microstructural Development in A356 Alloy Directionally Solidified under Unsteady-state Conditions

Microstructure development is well accepted to have a major effect on mechanical properties during its services. One of the most interesting ways to improve mechanical properties is to reduce secondary dendrite arm spacing （SDAS）.SDAS also plays an important role in controlling and providing the well distributed and fine microstructure resulting in better tensile strength and elongation.To reduce SDAS,it is commonly known by increasing cooling rate and increasing interface instability by limited-soluble alloy addition.It is,however, unclear that how both cooling rate and limited-soluble alloy,e.g.Sb,relate to each other.This may be the reason that the limited-soluble alloy may not effectively reduce SDAS.To better understand this phenomenon, influences of Sb on solid/liquid interface instability using columnar to equiaxed transition （CET） were studied in the directionally solidification experiment.From macrographs and micrographs,it was observed that at 0.06-0.18 wt pct Sb the CET min,CET max,CET zone and %CET area gradually increased.The increases of CET max and CET zone in samples with 0.06 to 0.18 wt pct Sb addition results from recalesced zone.On the other hand,the variations of CET max and CET zone in samples with 0.24 to 0.30 wt pct Sb results from equiaxed grain formations that prohibit the growth of columnar grain and latent heat from intermetallic phase solidified.

Investigation on gasification of glycerol and palm shell mixed wastes by fluidization system

In this paper, gasification was utilized in order to produce syngas from crude glycerol and palm shell waste which are by-product of biodiesel production. Experiments were carried out in a fluidized bed quartz reactor using alumina ball with 1 mm diameter as fluidizing medium with equivalent ration of 0.05 with raw materials （mixed crude glycerol and palm shell wastes） at 10 g/min feed rate under 700℃ and 900℃. Glycerol and palm shell powder were fed separately to gasifier at different weight ratio varied from 100：0, 70：30, 50：50, 30：70, 0：100. Decomposition of crude glycerol resulted in much less char when compared with other biomass. From the results, it could be found that combustible gas productions increased with the increasing of crude glycerol fraction and temperature; syngas production was highest at 900℃with only glycerol in feed; gas production rate yields under optimum condition were 4.29% CO2, 8.70% CO, 10.48% H2, and 8.24% CH4 L/min; LHV and H2/CO at optimum condition were 4.87 MJ/m^3 and 1.20, respectively, which were sufficient for power utilization. Obtained H2/CO ratio also indicated that syngas from gasification of crude glycerol and palm shell waste should be suitable for further conversion to methanol and other chemical reagents, and thus closing the chemical recovery cycle of biodiesel production process to ensure the sustainahility status for the use of biodiesel as a prominent renewable energy source.

Influence of Al2O3 and TiO2 supports on catalytic performance of Ni and Co catalysts for gasification of glycerol waste

Since the constant increase in petroleum price, use of glycerol waste, which is a byproduct from biodiesel production, as a partial replacement for fossil fuels via thermochemical conversion waste to energy processes is more practical. Gasification reaction has attracted a lot of interest by producing syngas rich in CO and H2. This syngas can be converted to clean liquid fuels, such as methanol and Fischer-Tropsch oil. Nickel and Cobalt catalyst was widely used in steam reforming reaction. ethanol etc. The aim of this work is to prepare and characterize 5.0 and 10.0%wt of Ni and Co catalysts using the impregnation method on various supporters, such as alumina and titanium oxide （TiO2） and to evaluate their catalytic performance. The specific surface area of developed catalysts was measured. X-ray diffraction （XRD） was applied to determine phase and crystallized size of the catalysts. Examination of the morphology. elemental composition and distribution of metal on the catalysts support were carried out using scanning electron microscopy （SEMi and energy dispersion spectroscopy （EDS） and x-ray mapping. The catalytic performance of prepared catalysts was test at 700 and 900℃ temperature of reaction. 1.87% O2. The result showed that the synthesized nickel and cobalt catalysts via impregnation method using Al2O3 and TiO2 as the catalyst support were suitable for glycerol conversion.

Industrial development of gas induced semi-solid process

The gas induced semi-solid(GISS) is a rheocasting process that produces semi-solid slurry by applying fine gas bubble injection through a graphite diffuser.The process is developed to be used in the die casting industry.To apply the GISS process with a die casting process,a GISS maker unit is designed and attached to a conventional die casting machine with little modifications.The commercial parts are developed and produced by the GISS die casting process.The GISS die casting shows the feasibility to produce industrial parts with aluminum 7075 and A356 with lower porosity than liquid die casting.

Fractional four-step finite element method for analysis of thermally coupled fluid-solid interaction problems

An integrated fluid-thermal-structural analysis approach is presented. In this approach, the heat conduction in a solid is coupled with the heat convection in the viscous flow of the fluid resulting in the thermal stress in the solid. The fractional four-step finite element method and the streamline upwind Petrov-Galerkin （SUPG） method are used to analyze the viscous thermal flow in the fluid. Analyses of the heat transfer and the thermal stress in the solid axe performed by the Galerkin method. The second-order semi- implicit Crank-Nicolson scheme is used for the time integration. The resulting nonlinear equations are lineaxized to improve the computational efficiency. The integrated analysis method uses a three-node triangular element with equal-order interpolation functions for the fluid velocity components, the pressure, the temperature, and the solid displacements to simplify the overall finite element formulation. The main advantage of the present method is to consistently couple the heat transfer along the fluid-solid interface. Results of several tested problems show effectiveness of the present finite element method, which provides insight into the integrated fluid-thermal-structural interaction phenomena.

Molecular Dynamics Simulation of Strontium Titanate

The molecular dynamics method is used to simulate the thermophysical properties of SrTiO3 thermoelectric material in the temperature range 300-2200 K. The Morse-type potential functions added to the Busing-Ida type potential for interatomic interaction are used in the simulation. The interatomic potential parameters are determined by fitting to the experimental data of lattice parameters with temperature and the data reported in literature. The linear thermal expansion coefficient, heat capacity and lattice contributions to the thermal conductivity are analyzed. The results agree with the data reported in the literature.

Frequency-dependent magnetoelectricity of CoFe_2O_4-BaTiO_3 particulate composites

CoFe2O4-BaTiO3 particulate composites were prepared by wet ball milling method,their magnetoelectric（ME） effect was studied as a function of their constituents and modulation frequency.The results show that the ME coefficient increases as a function of modulation frequency from 400 to 1000 Hz and the ME characteristics of ME curves are also modified because the electrical conductivity of the CoFe2O4 phase is sensitive to the increase in frequency between 400 and 1 000 Hz.The third phase Ba2Fe2O5 formed during the sintering tends to reduce the ME effect.

Dielectric Properties of ZrTiO4 Thin Films Prepared by Reactive DC Magnetron Co-sputtering

ZrTiO4 is a small ceramic constituent material which has very good thermal and electrical properties. ZrTiO4 thin films were deposited by reactive dc magnetron co-sputtering method. The crystal structure, surface morphology, thickness and dielectric properties were characterized by XRD （X-ray diffraction）, AFM （atomic force microscopy）, FE-SEM （field emission scanning electron microscope）, and precision impedance analyzer respectively. These films were crystallization of the orthorhombic phase （111） of ZrTiOa. The microstructure of well-crystallized ZrTiO4 thin films had the surface morphology was smooth with 1.695 nmrms roughness. The high dielectric constant width decreases from 129.2 to 110.6 when sputtering current increases which are higher more than that had researched because of higher energy but impedance; ｜Z｜ increases from 1.97 to 2.47 kΩ. These results are consistent with the RMS roughness results, which are the RMS roughness decrease with increasing sputtering current.

Mechanical properties of squeeze-cast Al-7Si-0.3Mg alloys with Sc-modified Fe-rich intermetallic compounds

Iron （Fe） has a low solid solubility in aluminum （Al）, and it usually forms Fe-rich intermetallic compounds. Scandium （Sc） is an element that can act as a grain refiner, modify the eutectic silicon and change the morphology of Fe-rich intermetallic compounds at the same time. The present work was conducted to study the effect of Sc on the mechanical properties of Al-7Si-0.3Mg. The alloy was prepared by squeeze casting at two levels of Fe （0.2 and 0.4 wt%） and three levels of Sc （0 wt%, 0.2 wt% and 0.4 wt%）. Sc is found to increase the mechanical properties of the alloy, including its hardness, yield strength and ultimate tensile strength. At 0.2 wt% Fe, adding Sc increases the strength while maintaining good elongation. At 0.4 wt% Fe, adding Sc increases the strength but decreases the elongation slightly. The distributions and morphologies of intermetallic compounds and eutectic silicon affect the elongation. Both Fe-rich intermetallic compounds and Sc-rich intermetallic compounds act as crack initiation sites. The 0.2 wt% Fe ＋ 0.2 wt% Sc alloy has the lowest amount of these intermetallic compounds, and eutectic silicon is small and fibrous. So, it has the highest elongation.

Effect of synthesis time on morphology of CeO2 nanoparticles and Au/CeO2 and their activity in oxidative steam reforming of methanol

Ceria(CeO2)supports,synthesized by hydrothermal treatment with different synthesis time(CeO2-X h,where X is the synthesis time in h)in the presence of the surfactant cetyltrimethyl ammonium bromide,were used as supports for gold(Au)catalysts.The synthesis time significantly affects the morphological structure and crystallite size of CeO2,where CeO2-2 h has the smallest crystallite size with coexisting nanorods and nanoparticles.Transmission electron microscopy analysis confirms the morphology of CeO2 with distinctive(110),(100)and(111)planes,in agreement with interplanar spacings of 0.19,0,27 and 0.31,respectively.However,the morphology of CeO2-8 h and CeO2-48 h is mainly a truncated octahedral with crystal planes(111)and(100)accompanied by an interplanar spacing of 0.31 and0.27 nm,respectively.The CeO2-X h supports and those with a 3 wt%Au loading(Au/CeO2-X h)were investigated in the oxidative steam reforming of methanol at temperatures between 200 and 400℃.The Au/CeO2-2 h gave the highest methanol conversion level and hydrogen yield at a low temperature of 250℃.This superior catalytic performance results from the good interaction between the metal and support and the well-distributed Au species on the CeO2 support.

Effects of Porous Alumina Support and Plating Time on Electroless Plating of Palladium Membrane

The present work was focused on the preparation of palladium alloy membranes and the effect of properties of ceramic support on the composited membrane morphology. Palladium-base membrane is known to have high selectivity and stability for hydrogen separation. In order to increase hydrogen permeation and separation factor, the membrane must be thinner and defect-free. Palladium membrane supported on a porous alumina prepared by electroless plating is the promising method to provide good hydrogen permeability. The alumina tube substrate was pre-seeded by immersing in the palladium acetate solution and followed by reduction in the alkaline hydrazine solution. After that, the deposition of palladium membrane could be achieved from the plating bath containing ethylenediamine tetraacetic acid （EDTA） stabilized palladium complex and hydrazine. The morphology of palladium film was observed to progress as a function of plating time and a dense layer membrane was available after plating for 3 h. The porosity of ceramic support exhibited an effect on the microstructure of deposited film such that the support with low porosity tended to achieve a defect free palladium membrane.

Effect of samarium and praseodymium addition on water gas shift performance of Co/CeO2 catalysts

The performance of Co supported over ceria and doped ceria(by Sm and Pr)catalysts towards the water gas shift reaction was studied for the removal of CO from syngas to produce high purity hydrogen for a fuel cell application.It is found that 1%Co/Ce-5%Sm-O yields the highest catalytic performance towards this reaction compared with undoped-Sm and doped-Pr.An addition of Sm onto ceria support reveals a small crystallite size with high surface area and well dispersed cobalt on ceria surface.Moreover,a presence of Sm increases the reducibility of cobalt species and surface oxygen.The positive effect of Sm on increasing the WGS activity of Co/CeO2 is because Sm contributes to the reduction of Ce^4+to Ce3+which gives rise to oxygen vacancies and facilitates the electron movement at the surface leading to an ease of surface reduction.