Copper Oxide Layers

With outstanding integration of mechanical performances and biocompatibility, 3 mol% of yttria stabilised tetragonal zirconia polycrystals (3Y-TZP) ceramic are extensively fabricated as biomedical implants. Conventional sintering (CS) was generally employed to produce 3Y-TZP bodies with promising densification, which resulted in grain coarsening and mechanical properties deterioration due to elevated sintering temperatures (> 1500°C). The main weakness of 3Y-TZP ceramic is the spontaneous tetragonal to monoclinic phase transformation under humid environment, which is known as low-temperature degradation (LTD). In present work, undoped and MnO 2 (0.3 and 0.5 wt%) doped 3Y-TZP green bodies were prepared and subjected to CS at 1200-1500°C for an hour of dwelling time. It was found that the optimum concentration of MnO 2 dopant was 0.5 wt%. Reasonable toughness values of 5-7 MPa.m 1/2 revealed the tetragonal phase stability of 3Y-TZP grains was not altered by doping of MnO 2 . Moreover, outstanding density level of > 96% of 0.5 wt% MnO 2 doped 3Y-TZP ceramics demonstrated the superb Young's modulus of > 200 GPa and Vicker's hardness of >13 GPa. Fabrication of 3Y-TZP by doping MnO 2 had reduced the total processing time by ~ 9% and sintering temperature by up to 150°C when compared to undoped 3Y-TZP ceramics sintered at 1400°C.

Doping of Si nanocrystals (NCs) has been the subject of a strong experimental and theoretical debate for more than a decade. A major difficulty in the understanding of dopant incorporation at the nanoscale is related to the fact that theoretical calculations usually refer to thermodynamic equilibrium conditions, whereas, from the experimental point of view, impurity incorporation is commonly performed during NC formation. This latter circumstance makes impossible to experimentally decouple equilibrium properties from kinetic effects. In this report, we approach the problem by introducing the dopants into the Si NCs, from a spatially separated dopant source. We induce a P diffusion flux to interact with the already-formed and stable Si NCs embedded in SiO 2 , maintaining the system very close to the thermodynamic equilibrium. Combining advanced material synthesis, multi-technique experimental quantification and simulations of diffusion profiles with a rate-equation model, we demonstrate that a high P concentration (above the P solid solubility in bulk Si) within Si NCs embedded in a SiO 2 matrix corresponds to an equilibrium property of the system. Trapping within the Si NCs embedded in a SiO 2 matrix is essentially diffusion limited with no additional energy barrier, whereas de-trapping is prevented by a binding energy of 0.9 eV, in excellent agreement with recent theoretical findings that highlighted the impact of different surface terminations (H-or O-terminated NCs) on the stability of the incorporated P atoms.

This study focused on the fabrication of copper oxide (CuO) thin films using the sol-gel dip-coating technique, with precursor molar concentrations of 0.3 and 0.75 M, to create Ag/CuO/n-Si/Ag heterojunction diodes. The electrical characterization was performed in both dark conditions and under illumination (100 to 200 mW/cm2) to examine the effects of precursor concentration on device performance. Key electrical parameters, including saturation current, barrier height, ideality factor, series resistance, and rectification ratio, were extracted from the current–voltage (I–V) characteristics using thermionic emission theory and Cheung’s method. Additionally, the forward bias I–V characteristics were analyzed with the space charge limited current (SCLC) model to identify the dominant conduction mechanisms. The ideality factors decreased from 3.83 to 2.9 for our samples as the molar concentration increased. Nonetheless, the barrier height was observed to rise with an increase in molar concentration, measuring 0.6 eV for 0.3 M and 0.61 eV for 0.75 M molar concentration, respectively. Atomic force microscopy (AFM) results showed that higher concentrations of precursors led to smoother surfaces with a decrease in roughness from 26.47 to 18.96 nm and also led to a decrease in grain sizes from 32.53 to 15.73 nm, which are often correlated with improved electrical performance. Overall, the findings of this study provide valuable insights into the relationship between precursor concentration, morphological features, and electrical characteristics of heterojunction diodes, contributing to the optimization of design and fabrication processes for enhanced performance in various optoelectronic applications.

The influence of small additions of MnO 2 (up to 1 wt. %) on the sintering behaviour of yttria-stabilized zirconia sintered over the temperature range from 1250°C to 1500°C was investigated. It was found that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. The results revealed that relative densities above 97.5 % of theoretical (i.e. > 5.95 Mg m-3) could be obtained in Y-TZPs sintered at low temperatures, 1250°C and 1300°C, with the additions of ≥ 0.3 wt. % MnO 2. In comparison to the undoped samples, the additions of up to 1 wt. % MnO 2 and for sintering up to 1350°C was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt. % MnO 2-doped samples when sintered above 1400°C. The relation between the measured mechanical properties is discussed with the emphasis on the role of the manganese oxide.

The article presents the type of wear of Al2O3 layers produced on the aluminium alloy EN AW-5251 depending on the production parameters. Oxide layers were produced by using DC anodizing in a ternary electrolyte at variable current density and electrolyte temperature. The layer scratch tests were carried out using a Micron- Gamma microhardness tester. The scratches of oxide layers were tested for the geometric structure of the surface using a Form TalySurf 2 50i contact profilograph. Contact thickness measurements were also made using a Dualscope MP40 device based on the eddy-current method. Using a scanning microscope (SEM), photos of the sample surfaces were taken to show and compare the surface morphology of the anodized layers in various parameters. Based on the research, it can be concluded that changes in the conditions of the production process of Al2O3 layers (electrolyte temperature and current density) have an impact on the type of tribological wear and changes in layer thi...

A single-step method was developed for methyl ester production from palm oil using tin-empty palm bunch ash impregnated zeolite (Sn-PBA-Zeolite) as heterogeneous catalyst. The weight ratios between Sn solution and zeolite 1:4, while the weight of the PBA was varied from 5, 10, 15, 20, 25, and 30 g in 60 mL of distilled water. Effects of reaction time, molar ratio of reactants, and catalyst concentration on the yield of methyl ester were studied. Characteristics of methyl ester produced were also investigated. The optimal conditions for transesterification reaction carried out by using a Sn-PBA-Zeolite of 1:4:25 weight ratio were a palm oil/methanol molar ratio 1:6, catalyst concentration (3% wt/wt), and 3 hours reaction time, whereas the maximum yield of methyl ester reached 76.21% wt/wt. The optimal conditions for esterification reaction carried out by using a Sn-PBA-Zeolite of 1:4:5 weight ratio were a palm oil/methanol molar ratio 1:12, catalyst concentration (3% wt/wt), and 3 ho...

The scarcity of the fossil fuel, environmental pollution and food crisis are the world's major issues in current era. Biodiesel is an alternative to diesel fuel, environment friendly and biodegradable and is produced from either edible or non-edible oils. In this study, a non-edible rubber seed oil (RSO) with high free fatty acid (FFA) content of 45% were used for the production of biodiesel. The process comprises of two steps. The first step is the acid esterification to reduce the FFA value and the second step is the base transesterification. The response surface methodology (RSM) was used for parametric optimization of the two stage processes i.e. acid esterification and base transesterification. The yield of biodiesel was analyzed using gas chromatography. The FTIR (Fourier Transform Infra-Red) spectrum was also determined to confirm the conversion of fatty acid to methyl esters. The fuel properties were analyzed according to the ASTM D6751 and EN14214 and were compared with the previous finding of researchers. All analyzed properties fulfilled the biodiesel standard criteria.

Biodiesel is a promising renewable alternative fuel to fossil energy. For the biodiesel production from non-edible oil feedstocks like Jatropha curcas oil, a pre-treatment step is essential, which is the esterification of free fatty acids in the feedstocks in order to avoid soap formation and minimize catalyst deactivation. The FFA used in this experiment was obtained by two methods which saponification, where oil (Jatropha oil) is converting to soap and also acidification, where the sodium salts of free fatty acids are converted to FFA by using hydrochloric acid (HCL). In this research, Calcium Ferrite (CaFe2O4) catalyst was prepared for the esterification of FFA. Due to its ability as an effective catalyst and without changing its crystal structure, Calcium Ferrite can yield high conversion of FFA into biodiesel. Calcium Ferrite catalyst was synthesized by Pechini method. Pechini process was newly used in this field of catalyst production. It is a powder-synthesis process that inv...

The article presents the effect of the anodizing parameters, as well as the thermo-chemical treatment, of Al2O3 layers produced on an aluminum alloy on the characterization of structure, geometrical structure of the surface (SGS), the thickness of the oxide layers, the phase composition, and their microhardness. The oxide layers were produced by the method of direct current anodizing in a three-component electrolyte. Then, thermo-chemical treatment was carried out in distilled water and aqueous solutions of sodium dichromate and sodium sulphate. The anodizing parameters and compounds for the thermo-chemical treatment were selected on the basis of Hartley’s plans. The research showed the effect of anodizing parameters on the thickness of the Al2O3 layers and the increase in the thickness of the layers as a result of the thermo-chemical treatment. The research showed a significant increase in the microhardness of the layers as a result of thermo-chemical treatment and its influence on...

The utilisation of waste biomass in biodiesel production as a sustainable energy source can lead to the incorporation of circular bioeconomy principles in the current economic systems. Herein, we synthesised a magnetically recyclable solid acid catalyst for the esterification of waste date seed oil. The catalysts possessed superparamagnetic behaviour and high saturation magnetisation, allowing them to be easily separated from the reaction mixture using an external magnetic filed. The esterification reaction was modelled and optimised by RSM (Design Expert program) and parametric study. The magnetic solid acid catalyst showed high catalytic performance with 91.4 % biodiesel yield with optimum conditions of residence time, catalyst loading and temperature of 47 min, 1.5wt %, and 55 o C, respectively. The solid catalyst was easily recovered by simple magnetic decantation and reused five consecutive times without significant degradation in its catalytic activity. This approach of using waste date seed coupled with cheap magnetic solid acid catalyst has the potential to create more sustainable and cheap catalytic systems for biodiesel production. This will complete the full cycle of waste date seed sustainably and facilitate the development of circular bioeconomy. The LCA results by using CML-IA baseline V3.06 midpoint indicators, for 1000 kg of biodiesel production showed the cumulative abiotic depletion of fossil resources over all the processes as 19037 MJ, global warming potential as 1114 kg CO2 eq, and human health toxicity as 633 kg 1,4-DB eq (kg 1,4 dichlorobenzene eq). The highest damage in all categories was observed during catalyst preparation, and reuse, which was also confirmed in endpoint LCA findings performed using ReCiPe 2016 Endpoint (E) V1.04).

The aim of this paper is to study the properties of copper oxide thin films prepared by electrolysis method and deposited on glass substrates by drop-casting method at different annealing temperatures. Copper oxide colloidal was successfully prepared by electrolysis method. The X-ray diffraction confirms the polycrystalline structure of the films. Atomic force microscopy shows that the increase in the annealing temperature improves the surface morphology, increases the grain size and removes the cracks. The best optical transmittance was for the film annealed at 200 oC. The bandgap decreases from 3.35 eV to 3.15 eV as a result of increasing the annealing temperature. The wide bandgap that obtained in this study is due to quantum size effect.

3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramic is widely used as engineering material owing to its great strength. Recently, 3Y-TZP ceramic is receiving great response in dental restoration due to its bio-compatible properties and aesthetic appearance. To achieve high bulk density, high sintering temperature (> 1500 °C), low firing rate (10 °C/min) coupled with long dwelling period (2 hours) are required in conventional sintering (CS) to fabricate 3Y-TZP ceramic which resulted in high energy consumption. Therefore, non-conventional sintering technique with low energy consumption such as microwave (MW) sintering is worth to explore as almost 100 % of electromagnetic energy is converted into heat largely within the sample itself. The commercial available 3Y-TZP powder was MW fired from 1200 °C to 1400 °C. The 3Y-TZP ceramics fabricated via MW sintering was compared with those CS samples by assessing the densification and mechanical properties of the cerami...

Cuprous oxide (Cu 2 O) and cupric oxide (CuO) films of nanometric thicknesses on monocrystalline (100) silicon were grown by thermal cupper oxidation technique. The copper nanofilms were deposited on crystalline (100) silicon by autocatalysis using watery solutions based on copper sulphate (CuSO 4) and hydrofluoric acid (HF). The Cu 2 O was obtained at an annealing temperature of 200ºC, whereas for the CuO was necessary to use a higher oxidation temperature, 600ºC for 3 h. The thicknesses of the copper oxide layers were ranged from 30 to 150 nm obtained by ellipsometry. For the characterization of the oxidized copper layers, cuprous and cupric of oxides, were used different techniques. In order to examine the surface morphology of the films atomic force microscopy (AFM) was used and for the identification of the different oxides crystalline phases was used X-ray diffraction. By means of the Debye-Scherrer equation the nanocrystal size that forms the copper-based nanofilms was estimated. For the Cu nanofilm in the diffraction peak (111), a crystal size of 16.82 nm is obtained. Similarly, for Cu 2 O, the nanocrystal size is 8.11 nm and for the CuO, the size is 6.66 nm, which indicates that crystal size depends of the annealing temperature. The refractive indexes measured for the nanofilms oxidized at 200ºC was from 2.2-2.3 and for the obtained ones at 600ºC was from 2.7-2.9. Keywords-AFM, Cu x O, thermal oxidation technique, XRD. I. INTRODUCTION HE interest by the study and preparation of copper oxide thin layers is by their use in the manufacture of toxic gas sensor elements [1.2].

Doping of Si nanocrystals (NCs) has been the subject of a strong experimental and theoretical debate for more than a decade. A major difficulty in the understanding of dopant incorporation at the nanoscale is related to the fact that theoretical calculations usually refer to thermodynamic equilibrium conditions, whereas, from the experimental point of view, impurity incorporation is commonly performed during NC formation. This latter circumstance makes impossible to experimentally decouple equilibrium properties from kinetic effects. In this report, we approach the problem by introducing the dopants into the Si NCs, from a spatially separated dopant source. We induce a P diffusion flux to interact with the already-formed and stable Si NCs embedded in SiO 2 , maintaining the system very close to the thermodynamic equilibrium. Combining advanced material synthesis, multi-technique experimental quantification and simulations of diffusion profiles with a rate-equation model, we demonstrate that a high P concentration (above the P solid solubility in bulk Si) within Si NCs embedded in a SiO 2 matrix corresponds to an equilibrium property of the system. Trapping within the Si NCs embedded in a SiO 2 matrix is essentially diffusion limited with no additional energy barrier, whereas de-trapping is prevented by a binding energy of 0.9 eV, in excellent agreement with recent theoretical findings that highlighted the impact of different surface terminations (H-or O-terminated NCs) on the stability of the incorporated P atoms.

Indium oxide films were deposited on glass substrates at room temperature by reactive rf sputtering. The depositions were carried out by sputtering pure indium in an Ar + 0 2 plasma. The influence of oxygen partial pressure during deposition on the optical, electrical, and structural properties of the films was investigated. The properties of the films were also studied after post-deposition heat treatments in air and in argon atmosphere. The study shows that conducting transparent films with resistivity 1.3 x 52 cm and transmission above 88% can be obtained by depositing the films at high oxygen partial pressures (> 0.21 Pa) and then annealing in argon atmosphere at 500 "C for one hour.

The evolution of a Fe/z 0-TiO x /Pt(111) model catalyst in ultrahigh vacuum, studied by advanced surface science tools, reveals various phenomena occurring in different temperature ranges. In the room temperature (RT) < T < 460 K range, the deposited Fe atoms assemble as heterogeneous Fe and FeO x nanoparticles (NPs), templated by the ordered array of defects (troughs and picoholes) of the oxide film. At 460 < T < 810 K, FeO x NPs become predominant, and a metastable FeO x /TiO x mixed oxide is formed, assisted by the interdiffusion of Fe through the oxide into the Pt substrate, which triggers the z 0-TiO x structure transformation into a different TiO x phase with a hexagonal pattern. At 810 < T < 1000 K, a Fe-mediated extraction of Pt produces Pt(111) islands, surrounded and partly encapsulated by the same z 0-TiO x phase, demonstrating the intrinsic high stability of the ultrathin oxide film. This represents one of the first examples of a phase transformation in a ultrathin oxide layer induced by an external metal deposit.

The effect of employing a short sintering holding time of 12 min as compared to that of the commonly employed holding time of 120 min (2 h) on the properties of undoped and 1 wt% manganese oxide (MnO 2)-doped Y-TZP ceramics were studied. Sintering studies was conducted over the temperature range of 1150-1600 8C. Bulk density, Young's modulus, Vickers hardness and fracture toughness tests were carried out on the sintered samples. The results revealed that the 12 min sintering holding time was effective in promoting densification of the 1 wt% MnO 2-doped Y-TZP without sacrificing tetragonal phase stability or mechanical properties and incurring grain growth. Microstructure investigation by using the scanning electron microscope (SEM) of the fracture MnO 2-doped Y-TZP samples which was subjected to rapid quenching in liquid nitrogen revealed distinct microstructural features believed to be associated with the presences of a transient liquid phase during sintering. A sintering mechanism was subsequently proposed to explain the densification behaviour of MnO 2-doped Y-TZP ceramics.

h i g h l i g h t s " A sulfated titania-silica catalyst is synthesized from less expensive precursors. " The catalysts are used to catalyze esterification and transesterification reactions. " S-TSC-450 and S-TSC-550 possess high activity comparable to that of pure H 2 SO 4. g r a p h i c a l a b s t r a c t FE-SEM images for as-synthesized samples of TSC (a), S-TSC (b), S-TSC-550 (c) and the TEM micrograph of S-TSC (d).

The surface composition of deoxidized high phosphorus (DHP) copper sheets was investigated by ESCA with the aim of verifying the role of phosphorus in oxide formation. While no surface segregation of phosphorus was observed on samples cleaned by ion bombardment and annealing in ultrahigh vacuum, the presence of large amounts of phosphorus was found after the formatiou of the oxide by exposure to 0.1 Torr oxygen at 770 K. The surface enrichment in P with the same binding energy was found after annealing a sheet of DHP copper coated with a layer of Cu,O deposited by sputtering. The binding energy of the P 2p peak as well as the analysis of the components of 0 1s can be interpreted with the formation of a metaphosphate. Experiments performed at intermediate temperatures showed that the segregation of phosphorus is appreciable above 600 K and appears to be related to oxygen diffusion into the bulk.

In this study, first rapeseed oil was extracted by different ratio of Methanol/n-Hexane mixture as solvent during 8 h in a Soxhlet extractor. During all experiments the other parameters such as amount of solvent (250 cc) and rapeseed (45 g), stirrer speed (750 rpm) and temperature (808C) were kept constant. The maximum yield of oil (45.33%) was obtained by 50/50% (Methanol/n-Hexane) volumetric ratio. Later, the extraction and trans-esterification were carried out simultaneously employing each of the two selected alkali catalysts. The results showed that applying of 11% (wt%) CaO for 8 h, produced the ultra-pure biodiesel of 99.92% having yield of 80.49% whereas using 2% KOH for 4 h, resulted 95.74% purity with the yield of 87.23%.

Heterogeneous acid catalyst comprising 12-tungstophosphoric acid (30%) and MCM-41 was synthesized and characterized by X-ray diffraction (XRD), surface area measurement (BET method), and solid state 29 Si NMR. The use of synthesized catalyst was explored for biodiesel production by esterification of free fatty acid, palmitic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, and temperature were studied to optimize the conditions for maximum conversion. The catalyst shows high activity in terms of 100% conversion toward palmitic acid and a high turnover number, 1992. The kinetic studies as well as the Koros Nowak test were also carried out, and it was found that esterification of palmitic acid follows first order kinetics and the rates are not mass transfer limited. The excellent catalytic performance is attributed to the large surface area and pore diameter of the mesoporous support, MCM-41 as well as the Bronsted acid strength of TPA, as active sites. The catalyst shows the potential of being used as a recyclable catalytic material after simple regeneration without significant loss in conversion. As an application, preliminary studies were carried out for biodiesel production from waste cooking oil, as feedstock without any pretreatment, and with methanol over the present catalyst. Studies also reveal that the catalyst can be used for biodiesel production from waste cooking oil.

Microbial oils are considered as alternative to vegetable oils or animal fats as biodiesel feedstock. Microalgae and oleaginous yeast are the main candidates of microbial oil producers' community. However, biodiesel synthesis from these sources is associated with high cost and process complexity. The traditional transesterification method includes several steps such as biomass drying, cell disruption, oil extraction and solvent recovery. Therefore, direct transesterification or in situ transesterification, which combines all the steps in a single reactor, has been suggested to make the process cost effective. Nevertheless, the process is not applicable for large-scale biodiesel production having some difficulties such as high water content of biomass that makes the reaction rate slower and hurdles of cell disruption makes the efficiency of oil extraction lower. Additionally, it requires high heating energy in the solvent extraction and recovery stage. To resolve these difficulties, this review suggests the application of antimicrobial peptides and high electric fields to foster the microbial cell wall disruption.

Studies on the electronic and optical properties of thin films of organometallic compounds such as phthalocyanine are very important for the development of devices based on these compounds. The nucleation and grain growth mechanism play an important role for the final electronic as well as optoelectronic properties of the organic and organometallic thin films. The present article deals with the change in the film morphology, grain orientation of nanocrystallites and optical properties of zinc phthalocyanines (ZnPc) thin films as a function of the post deposition annealing temperature. The effect of annealing temperature on the optical and structural property of vacuum evaporated ZnPc thin films deposited at room temperature (30°C) on quartz glass and Si(100) substrates has been investigated. The thin films have been characterized by the UV-vis optical absorption spectra, X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy. From the studies of UV-vis absorption spectra and XRD data, a metastable α to β-phase transformation has been observed when the thin films were annealed at a temperature greater than about 250°C. The FESEM images have shown the particlelike structure at room temperature and the structure became rodlike when the films were annealed at high temperatures. TEM image of ZnPc film dissolved in ethanol has shown spectacular rod-shaped crystallites. High resolution transmission electron microscopy image of a single nanorod has shown beautiful "honey-comb" like structure. Particle size and root mean square roughness were calculated from AFM images. The changes in band gap energy with increase in annealing temperature have been evaluated.

The scarcity of the fossil fuel, environmental pollution and food crisis are the world's major issues in current era. Biodiesel is an alternative to diesel fuel, environment friendly and biodegradable and is produced from either edible or non-edible oils. In this study, a non-edible rubber seed oil (RSO) with high free fatty acid (FFA) content of 45% were used for the production of biodiesel. The process comprises of two steps. The first step is the acid esterification to reduce the FFA value and the second step is the base transesterification. The response surface methodology (RSM) was used for parametric optimization of the two stage processes i.e. acid esterification and base transesterification. The yield of biodiesel was analyzed using gas chromatography. The FTIR (Fourier Transform Infra-Red) spectrum was also determined to confirm the conversion of fatty acid to methyl esters. The fuel properties were analyzed according to the ASTM D6751 and EN14214 and were compared with the previous finding of researchers. All analyzed properties fulfilled the biodiesel standard criteria.

h i g h l i g h t s Catalyst CuO/C was prepared by a novel technique where activated carbon was introduced with nano-sol. The free fatty acid conversion was achieved up to 95% using 8 wt% catalysts. High catalytic activity was observed and activity was lost about 20% after four cycles uses.

In the present research, nano hydroxyapatite (HA) powder doped with magnesia (MgO) was studied. The dopant was added to pure HA powder and ball milling was done for 1 hour. Green samples, in the form of discs and rectangular bars, were prepared and consolidated in air at temperatures ranging from 1000 °C to 1300 °C. The sintered samples were characterized to determine the phase stability, relative density, hardness, fracture toughness and Young's modulus. The phase analysis revealed that the HA phase was not disrupted regardless of dopant additions and sintering temperature. It has been revealed that all HA samples achieved > 98% relative density when sintered between 1100 ºC-1300 ºC. However, the addition of 0.5 wt% MgO when sintered at 1100 °C was found to be most beneficial in aiding sintering with samples exhibiting the highest Young's modulus of 122.15 GPa and fracture toughness of 1.64 MPam 1/2 as compared to 116.57 GPa and 1.18 MPam 1/2 for the undoped HA.

Biodiesel is a promising renewable alternative fuel to fossil energy. For the biodiesel production from non-edible oil feedstocks like Jatropha curcas oil, a pre-treatment step is essential, which is the esterification of free fatty acids in the feedstocks in order to avoid soap formation and minimize catalyst deactivation. The FFA used in this experiment was obtained by two methods which saponification, where oil (Jatropha oil) is converting to soap and also acidification, where the sodium salts of free fatty acids are converted to FFA by using hydrochloric acid (HCL). In this research, Calcium Ferrite (CaFe2O4) catalyst was prepared for the esterification of FFA. Due to its ability as an effective catalyst and without changing its crystal structure, Calcium Ferrite can yield high conversion of FFA into biodiesel. Calcium Ferrite catalyst was synthesized by Pechini method. Pechini process was newly used in this field of catalyst production. It is a powder-synthesis process that inv...

The scarcity of the fossil fuel, environmental pollution and food crisis are the world's major issues in current era. Biodiesel is an alternative to diesel fuel, environment friendly and biodegradable and is produced from either edible or non-edible oils. In this study, a non-edible rubber seed oil (RSO) with high free fatty acid (FFA) content of 45% were used for the production of biodiesel. The process comprises of two steps. The first step is the acid esterification to reduce the FFA value and the second step is the base transesterification. The response surface methodology (RSM) was used for parametric optimization of the two stage processes i.e. acid esterification and base transesterification. The yield of biodiesel was analyzed using gas chromatography. The FTIR (Fourier Transform Infra-Red) spectrum was also determined to confirm the conversion of fatty acid to methyl esters. The fuel properties were analyzed according to the ASTM D6751 and EN14214 and were compared with the previous finding of researchers. All analyzed properties fulfilled the biodiesel standard criteria.

The surface composition of deoxidized high phosphorus (DHP) copper sheets was investigated by ESCA with the aim of verifying the role of phosphorus in oxide formation. While no surface segregation of phosphorus was observed on samples cleaned by ion bombardment and annealing in ultrahigh vacuum, the presence of large amounts of phosphorus was found after the formatiou of the oxide by exposure to 0.1 Torr oxygen at 770 K. The surface enrichment in P with the same binding energy was found after annealing a sheet of DHP copper coated with a layer of Cu,O deposited by sputtering. The binding energy of the P 2p peak as well as the analysis of the components of 0 1s can be interpreted with the formation of a metaphosphate. Experiments performed at intermediate temperatures showed that the segregation of phosphorus is appreciable above 600 K and appears to be related to oxygen diffusion into the bulk.

Biodiesel is a promising renewable alternative fuel to fossil energy. For the biodiesel production from non-edible oil feedstocks like Jatropha curcas oil, a pre-treatment step is essential, which is the esterification of free fatty acids in the feedstocks in order to avoid soap formation and minimize catalyst deactivation. The FFA used in this experiment was obtained by two methods which saponification, where oil (Jatropha oil) is converting to soap and also acidification, where the sodium salts of free fatty acids are converted to FFA by using hydrochloric acid (HCL). In this research, Calcium Ferrite (CaFe2O4) catalyst was prepared for the esterification of FFA. Due to its ability as an effective catalyst and without changing its crystal structure, Calcium Ferrite can yield high conversion of FFA into biodiesel. Calcium Ferrite catalyst was synthesized by Pechini method. Pechini process was newly used in this field of catalyst production. It is a powder-synthesis process that inv...

An easy synthesis route for cuprous oxide (Cu 2 O) nanoparticles is reported via thermal annealing improved and controlled by in-situ conductivity measurements. The crystalline structure, phase transition, surface morphology and particle size/shape, were investigated through Xray diffraction, a conductivity setup and scanning electron microscopy, respectively. X-ray diffraction patterns revealed that initial metallic Cu nanoparticles were transformed to Cu 2 O nanoparticles with high purity, under specific conditions critically dependent on the temperature and annealing duration. This transformation was also dependent on the film thickness and atmospheric composition in the test chamber during the annealing process.

The surface composition of deoxidized high phosphorus (DHP) copper sheets was investigated by ESCA with the aim of verifying the role of phosphorus in oxide formation. While no surface segregation of phosphorus was observed on samples cleaned by ion bombardment and annealing in ultrahigh vacuum, the presence of large amounts of phosphorus was found after the formatiou of the oxide by exposure to 0.1 Torr oxygen at 770 K. The surface enrichment in P with the same binding energy was found after annealing a sheet of DHP copper coated with a layer of Cu,O deposited by sputtering. The binding energy of the P 2p peak as well as the analysis of the components of 0 1s can be interpreted with the formation of a metaphosphate. Experiments performed at intermediate temperatures showed that the segregation of phosphorus is appreciable above 600 K and appears to be related to oxygen diffusion into the bulk.

This research focuses on the preparation, characterization and catalytic properties of novel magnesium oxide in mesoporous MCM-22 Silica (MgO/MCM-22) for biodiesel production from jatropha oil. The catalysts were prepared by impregnation method and characterized. Then, the catalyst were tested for biodiesel production from jatropha oil where the reaction parameters were studied. The obtained results of the characterization showed that, the prepared catalyst has an amorphous structure with high Si/Al ratio which changes to a more of crystalline structure after successful incorporation of MgO. The result of the transesterification shows that, magnesium oxide (MgO) supported with silica is highly effective for the production of biodiesel where the high fatty acid methyl ester of 98% was achieved. Furthermore, the synthesized catalyst was able to be used up to three times with a slight reduction in catalytic activity. Hence, it can be concluded that the catalyst prepared from MgO/MCM-22 can serve as an outstanding alternative catalyst for biodiesel production.

Biodiesel production by transesterification of rubber seed oil (RSO) using calcium oxide (CaO) derived from calcined limestone as a heterogeneous catalyst is presented in this study. Optimization of process parameters affecting the conversion of RSO to biodiesel is done by Design of Experiments (DOE) and an effective comparison of two different optimization methods,namely, Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) is presented. A high conversion of 95.2% was obtained at 12:1 methanol: Oil molar ratio, 4 (wt %) catalyst and 5 hours of reaction time. The proposed design model of RSM is found to fit well with the predicted conversion and with molar ratio and reaction time as the significant process parameters affecting the conversion. Best validation performance of 8.8991 occurred at epoch 4 with a mean square error (MSE) of 1.55 in ANN model trained with Levenberg-Marquardt algorithm. By comparing the predicted coefficient of determination, R 2 , values of 0.8452 obtained by using RSM and 0.9939 obtained by using ANN for biodiesel conversion, it is concluded that ANN model is the best model for

Alloying in traditional semiconductors is a well-established method to tune the electronic structure and the materials properties, but this technique is less common for oxides. Here, we present results on the non-equilibrium alloying of the prototypical semiconductor Cu 2 O with ZnO synthesized via high-throughput RF magnetron sputtering. It is demonstrated that the Zn solid solubility in Cu 2 O structure can be increased up to 17 at.% in the substrate temperature range 210-270°C; this upper bound estimate of the solubility limit is much higher than that at equilibrium (sub atomic percent range). The preferential orientation in the film changes from (200) to (111) with increasing Zn concentration, but the lattice parameter and the grain size (80-180 nm) remains constant. Incorporation of Zn into Cu 2 O increases the optical absorption fourfold at the band gap (2.1 eV) and reduces the p-type electrical conductivity by an order of magnitude. The ability to synthesize phase pure Cu 2-2x Zn x O alloys with Zn solid solubility in excess of the thermodynamic limit with tunable structural and optoelectronic properties demonstrates the potential of non-equilibrium growth to overcome the solubility limits in oxide thin films and the promise of such alloys for optoelectronic applications.

Cuprous oxide (Cu 2 O) is actively studied as a prototypical material for energy conversion and electronic applications. Here we reduce the growth temperature of phase pure Cu 2 O thin films to 300 • C by intentionally controlling solely the kinetic parameter (total chamber pressure, P tot) at fixed thermodynamic condition (0.25 mTorr pO 2). A strong non-monotonic effect of P tot on Cu-O phase formation is found using high-throughput combinatorial-pulsed laser deposition. This discovery creates new opportunities for the growth of Cu 2 O devices with low thermal budget and illustrates the importance of kinetic effects for the synthesis of metastable materials with useful properties.

In this study, first rapeseed oil was extracted by different ratio of Methanol/n-Hexane mixture as solvent during 8 h in a Soxhlet extractor. During all experiments the other parameters such as amount of solvent (250 cc) and rapeseed (45 g), stirrer speed (750 rpm) and temperature (808C) were kept constant. The maximum yield of oil (45.33%) was obtained by 50/50% (Methanol/n-Hexane) volumetric ratio. Later, the extraction and trans-esterification were carried out simultaneously employing each of the two selected alkali catalysts. The results showed that applying of 11% (wt%) CaO for 8 h, produced the ultra-pure biodiesel of 99.92% having yield of 80.49% whereas using 2% KOH for 4 h, resulted 95.74% purity with the yield of 87.23%.

The aim of this paper is to study the properties of copper oxide thin films prepared by electrolysis method and deposited on glass substrates by drop-casting method at different annealing temperatures. Copper oxide colloidal was successfully prepared by electrolysis method. The X-ray diffraction confirms the polycrystalline structure of the films. Atomic force microscopy shows that the increase in the annealing temperature improves the surface morphology, increases the grain size and removes the cracks. The best optical transmittance was for the film annealed at 200 oC. The bandgap decreases from 3.35 eV to 3.15 eV as a result of increasing the annealing temperature. The wide bandgap that obtained in this study is due to quantum size effect.

The effect of employing a short sintering holding time of 12 min as compared to that of the commonly employed holding time of 120 min (2 h) on the properties of undoped and 1 wt% manganese oxide (MnO 2)-doped Y-TZP ceramics were studied. Sintering studies was conducted over the temperature range of 1150-1600 8C. Bulk density, Young's modulus, Vickers hardness and fracture toughness tests were carried out on the sintered samples. The results revealed that the 12 min sintering holding time was effective in promoting densification of the 1 wt% MnO 2-doped Y-TZP without sacrificing tetragonal phase stability or mechanical properties and incurring grain growth. Microstructure investigation by using the scanning electron microscope (SEM) of the fracture MnO 2-doped Y-TZP samples which was subjected to rapid quenching in liquid nitrogen revealed distinct microstructural features believed to be associated with the presences of a transient liquid phase during sintering. A sintering mechanism was subsequently proposed to explain the densification behaviour of MnO 2-doped Y-TZP ceramics.

Highly mesoporous Ba(HPW 12 O 40) heterogeneous acid catalysts were successfully synthesized by the two-step impregnation method and characterized for their catalytic activities, the trans-esterification reaction of Karanja oil was evaluated. The various amounts of catalyst were loaded in the acidic medium and then Barium salt of tungstophosphoric acid. The acid catalyst was characterized using a techniques like FT-IR, XRD, BET, TGA, SEM and EDX.The results indicate that Ba 2þ was incorporated into the HPW 12 O 40 framework via isomorphous substitution between Ba 2þ ions. During the tests, it was observed that Ba (HPW 12 O 40), for transerterification of pongamia oil (89%) at optimized reaction conditions of 120 C, 16:1 methanol to reactant molar ratio, 0.75 wt% catalyst loading, and 3 hrs reaction time. The results show that all of the solids have catalytic activity in the cracking reaction, which lowers the ultimate acidity of the products. The solids also have catalytic activity in the transesterification of triglycerides, resulting in high ester yields of 95% from Pongamia oil. The biodiesel production from pongamia oils was characterized by FTIR analysis and 1 H-NMR spectroscopy. With significant activity and stability, the used catalysts could be recycled up to three times.

Here, we report the upgrading of shea butter to biodiesel with hierarchical mesoporous ZSM-5 zeolites (HMZeol). Shea butter is a triglyceride (mainly oleic and steric acid) extracted from African shea tree nut. The catalysts synthesis was by desilication of conventional ZSM-5 with an aqueous solution of NaOH (0.3 and 0.4 M). XRF, XRD, NH 3-TPD and N 2 adsorption unveiled the effect of desilication of the parent zeolite. The study investigated the effect of NaOH concentration on matrix area, pore size, mesopore volume and Si/Al ratio. HMZeol showed superior activity on biodiesel yield when compared with the parent ZSM-5 zeolite. The catalytic material treated with 0.4 M NaOH (0.4HMZeol) gave 74% biodiesel yield at 5:1 methanol/oil molar ratio, 1 wt% catalyst, and 200 ᵒ C for 3 h reaction time while ZSM-5 gave 46.05% yield under the same reaction conditions. Further increase in the reaction time to 12 h for 0.4HMZeol, 0.3HMZeol and ZSM-5 gave 82.12, 79.21, and 72.13% biodiesel yield respectively. These results showed that hierarchical mesoporous HZSM-5 is a promising solid acid catalyst for biodiesel production via methanolysis.

In this study, the potential of limestone based catalyst on microwave assisted closed heating transesterification of Malaysian rubber seed oil (RSO) which is rich in high Free Fatty Acid (FFA) was investigated. The experimental results showed that the conversion of high FFA oil to biodiesel is very efficient compared to various catalysts. The catalytic activity is not negatively affected by the free fatty acids and can be recycled very easily. Brunauer-Emmett-Teller (BET) analysis was also used to find the surface area of the catalyst at each cycle. The highest conversion achieved was 96.80% with catalyst concentration of 6 wt%; methanol to oil molar ratio of 5:1; reaction temperature of 60°C and reaction time of 60 minutes. The biodiesel produced is within the limits being prescribed by ASTM D 6751.

Doping of Si nanocrystals (NCs) has been the subject of a strong experimental and theoretical debate for more than a decade. A major difficulty in the understanding of dopant incorporation at the nanoscale is related to the fact that theoretical calculations usually refer to thermodynamic equilibrium conditions, whereas, from the experimental point of view, impurity incorporation is commonly performed during NC formation. This latter circumstance makes impossible to experimentally decouple equilibrium properties from kinetic effects. In this report, we approach the problem by introducing the dopants into the Si NCs, from a spatially separated dopant source. We induce a P diffusion flux to interact with the already-formed and stable Si NCs embedded in SiO 2 , maintaining the system very close to the thermodynamic equilibrium. Combining advanced material synthesis, multi-technique experimental quantification and simulations of diffusion profiles with a rate-equation model, we demonstrate that a high P concentration (above the P solid solubility in bulk Si) within Si NCs embedded in a SiO 2 matrix corresponds to an equilibrium property of the system. Trapping within the Si NCs embedded in a SiO 2 matrix is essentially diffusion limited with no additional energy barrier, whereas de-trapping is prevented by a binding energy of 0.9 eV, in excellent agreement with recent theoretical findings that highlighted the impact of different surface terminations (H-or O-terminated NCs) on the stability of the incorporated P atoms.

h i g h l i g h t s Catalyst CuO/C was prepared by a novel technique where activated carbon was introduced with nano-sol. The free fatty acid conversion was achieved up to 95% using 8 wt% catalysts. High catalytic activity was observed and activity was lost about 20% after four cycles uses.

The influence of small additions of MnO 2 (up to 1 wt. %) on the sintering behaviour of yttria-stabilized zirconia sintered over the temperature range from 1250°C to 1500°C was investigated. It was found that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. The results revealed that relative densities above 97.5 % of theoretical (i.e. > 5.95 Mg m-3) could be obtained in Y-TZPs sintered at low temperatures, 1250°C and 1300°C, with the additions of ≥ 0.3 wt. % MnO 2. In comparison to the undoped samples, the additions of up to 1 wt. % MnO 2 and for sintering up to 1350°C was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt. % MnO 2-doped samples when sintered above 1400°C. The relation between the measured mechanical properties is discussed with the emphasis on the role of the manganese oxide.

Microbial oils are considered as alternative to vegetable oils or animal fats as biodiesel feedstock. Microalgae and oleaginous yeast are the main candidates of microbial oil producers' community. However, biodiesel synthesis from these sources is associated with high cost and process complexity. The traditional transesterification method includes several steps such as biomass drying, cell disruption, oil extraction and solvent recovery. Therefore, direct transesterification or in situ transesterification, which combines all the steps in a single reactor, has been suggested to make the process cost effective. Nevertheless, the process is not applicable for large-scale biodiesel production having some difficulties such as high water content of biomass that makes the reaction rate slower and hurdles of cell disruption makes the efficiency of oil extraction lower. Additionally, it requires high heating energy in the solvent extraction and recovery stage. To resolve these difficulties, this review suggests the application of antimicrobial peptides and high electric fields to foster the microbial cell wall disruption.

In this study, copper oxide thin films prepared by the sol-gel method, have been deposed onto glass substrates by the spin coating technique. Our target was to study their properties and improve them for photovoltaic use. These properties were optimized by varying the temperature annealing and the molar concentration of the precursor solutions. The effects of the annealing temperature on the structural and optical properties of the thin films are studied. It was found that the film treated at 550°C shows a higher absorbance. Then by using this optimized temperature, CuO thin films of various molar concentrations, were deposited at the same experimental conditions. The structural analysis by X-ray diffraction (XRD) shows that all the samples are polycrystalline with monoclinic crystal structure. Raman scattering measurements of all thin films confirms the structure of CuO. The optical properties of the films were characterized by UV-Visible-NIR spectrophotometry, which shows that the films show high absorbance in the visible region. Their optical band gap decreases from 3.68 to 2.44 eV when the molar concentration of precursor solutions increases from 0.1 to 0.5 M. The electrical measurements show that the resistivity of the films varies slightly from 84 Ω cm to 124 Ω cm as the molar concentration increases.

Biodiesel synthesis from waste frying oil (WFO), gained a huge industrial concern compared to the high priced virgin vegetable oils. The major catalysts used in biodiesel production are homogeneous catalysts, which are cheap. However, they have many drawbacks such as, serious separation problems, low biodiesel production yield and production of impure glycerol. This will lead to increase the produced biodiesel price. The latest trend in biodiesel production today is using heterogeneous catalysts that can address the homogeneous catalysts drawbacks. CaSO 4-SiO 2-CaO/SO 4 2composites with various SiO 2 to CaO weight ratios were synthesized, characterized by XRD, SEM, EDX, and FTIR. In addition, the prepared composites were used for biodiesel production and for determining the optimum operating conditions using gas chromatograph (GC). The obtained results clearly indicate that CaSO 4-SiO 2-CaO/SO 4 2can be used as stable and active catalyst for biodiesel production from WFO.