Search results for: 4D scanning ultrafast microscopy

Authors: Rutuja Upadhyay, Anurag Mehra

Abstract:

Solid food foams/cellular foods are colloidal systems which impart structure, texture and mouthfeel to many food products such as bread, cakes, ice-cream, meringues, etc. Their heterogeneous morphology makes the quantification of structure/mechanical relationships complex. The porous structure of solid food foams is highly influenced by the processing conditions, ingredient composition, and their interactions. Sensory perceptions of food foams are dependent on bubble size, shape, orientation, quantity and distribution and determines the texture of foamed foods. The state and structure of the solid matrix control the deformation behavior of the food, such as elasticity/plasticity or fracture, which in turn has an effect on the force-deformation curves. The obvious step in obtaining the relationship between the mechanical properties and the porous structure is to quantify them simultaneously. Here, we attempt to research food foams such as bread dough, baked bread and steamed rice cakes to determine the link between ingredients and the corresponding effect of each of them on the rheology, microstructure, bubble size and texture of the final product. Dynamic rheometry (SAOS), confocal laser scanning microscopy, flatbed scanning, image analysis and texture profile analysis (TPA) has been used to characterize the foods studied. In all the above systems, there was a common observation that when the mean bubble diameter is smaller, the product becomes harder as evidenced by the increase in storage and loss modulus (G′, G″), whereas when the mean bubble diameter is large the product is softer with decrease in moduli values (G′, G″). Also, the bubble size distribution affects texture of foods. It was found that bread doughs with hydrocolloids (xanthan gum, alginate) aid a more uniform bubble size distribution. Bread baking experiments were done to study the rheological changes and mechanisms involved in the structural transition of dough to crumb. Steamed rice cakes with xanthan gum (XG) addition at 0.1% concentration resulted in lower hardness with a narrower pore size distribution and larger mean pore diameter. Thus, control of bubble size could be an important parameter defining final food texture.

Keywords: food foams, rheology, microstructure, texture

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Authors: D. V. S. Praneeth, V. R. Sankar Cheela, Brajesh Dubey

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Coal Combustion (CC) residues are the major by-products from thermal power plants. The disposal of ash on to land creates havoc to environment and humans. The leaching of the constituent elements pollutes ground water. Beneficiary use of coal combustion residues in structural components is being investigated as a part of this study. This application reduces stress on the convention materials in the construction industry. The present study involves determination of leaching parameters of the CC residues. Batch and column studies are performed based on Leaching Environmental Assessment Framework (LEAF) protocol. The column studies are conducted to simulate the real time percolation conditions in the field. The structural and environmental studies are performed to determine the usability of CC residues as bricks. The physical, chemical, geo environmental and mechanical properties of the alternate materials are investigated. Scanning electron microscopy (SEM), X-Ray Diffraction analysis (XRD), X-ray fluorescence (XRF) and Energy Dispersive X-ray Spectroscopy tests were conducted to determine the characteristics of CC residue ash and bricks.

Keywords: coal combustion residues, LEAF, leaching, SEM

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Authors: Obsi Terfasa, Bhanupriya Das, Shiao-Shing Chen

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Converting coal fly ash (CFA) waste into ceramic membranes presents a promising alternative to traditional disposal methods, offering potential economic and environmental advantages that warrant further investigation. This research focuses on the creation of ceramic membranes exclusively from CFA using a uniaxial compaction technique. The membranes' properties were examined through various analytical methods: Scanning Electron Microscopy (SEM) revealed a porous and flawless membrane surface, X-Ray Diffraction (XRD) identified mullite and quartz crystalline structures, and Fourier-Transform Infrared Spectroscopy (FTIR) characterized the membrane's functional groups. Thermogravimetric analysis (TGA) determined the ideal sintering temperature to be 800°C. To evaluate its separation capabilities, the synthesized membrane was tested on wastewater from denim jeans production at 0.2 bar pressure. The results were impressive, with 97.42% removal of Chemical Oxygen Demand (COD), 95% color elimination, and a pure water flux of 4.5 Lm⁻²h⁻¹bar⁻¹. These findings suggest that CFA, a byproduct of thermal power plants, can be effectively repurposed to produce ultrafiltration membranes suitable for various industrial purification and separations.

Keywords: wastewater treatment, separator, coal fly ash, ceramic membrane, ultrafiltration

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Authors: Omaima G. Allam, O. A. Hakeim, K. Haggag, N. S. Elshemy

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In the midst of the two decades the use of microwave dielectric warming in the field of science has transformed into a powerful methodology to redesign compound procedures. The potential benefit of the application of these modern methods of treatment emphasize so as to reach to optimum treatment conditions and the best results, especially hydrophobicity, moisture content and increase dyeing processing while maintaining the physical and chemical properties of each textile. Moreover, polyester fibres are sometimes spun together with natural fibres to produce a cloth with blended properties. So that at the present task, the polyester/viscose mix fabrics (60 /40) were pretreated with 4 g/l of KOH for 2 min in microwave irradiation with a liquor ratio 1:25. Subsequently fabrics were inundated with different concentrations of sericin (10, 30, 50 g/l). Treated fabrics were coloured with the commercial dyes samples: Reactive Red 84(Dye 1). C. I. Acid Blue 203(Dye 2) and C.I. Reactive violet 5 (Dye 3). Colour value was specified as well as fastness properties. Likewise, the physical properties of untreated and treated fabrics such as moisture content %, tensile strength, elongation % and were evaluated. The untreated and treated fabrics are described by infrared spectroscopy (FTIR) and scanning electron microscopy.

Keywords: polyester viscose blends fabric, sericin, dyes, colour value

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Authors: Seyedeh Narjes Hosseini, Mohammad Hossein Enayati, Fathallah Karimzadeh, Nigel Mark Sammes

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The synthesis of CuFe2O4 spinel powders by an optimized combustion-like process followed by calcinations is described herein. The samples were characterized by X-ray diffraction (XRD), differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), dilatometry and 4-probe DC methods. Different glycine to nitrate (G/N) ratios of 1 (fuel-deficient), 1.48 (stoichiometric) and 2 (fuel-rich) were employed. Calcining the as-prepared powders at 800 and 1000°C for 5 hours showed that the 2 ratio results in the formation of desired copper spinel single phase at both calcinations temperatures. For G/N=1, formation of CuFe2O4 takes place in three steps. First, iron and copper nitrates decomposes to iron oxide and pure copper. Then, copper transforms to copper oxide and finally, copper and iron oxides react to each other to form copper ferrite spinel phase. The electrical conductivity and the coefficient of thermal expansion of the sintered pelletized samples were obtained 2 S.cm-1 (800°C) and 11×10-6 °C-1 (25-800°C), respectively.

Keywords: SOFC interconnect coatings, Copper ferrite, Spinels, electrical conductivity, Glycine–nitrate process

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Authors: R. S. Rajpurohit, N. C. Santhi Srinivas, Vakil Singh

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Asymmetric stress cycling leads to accumulation of plastic strain which is called as ratcheting strain. The problem is generally associated with nuclear fuel cladding materials used in nuclear power plants and pressurized pipelines. In the present investigation, asymmetric stress controlled fatigue tests were conducted with three different parameters namely, mean stress, stress amplitude and stress rate (keeping two parameters constant and varying third parameter) to see the plastic strain accumulation and its effect on fatigue life and deformation behavior of Zircaloy-2 at 400°C. The tests were conducted with variable mean stress (45-70 MPa), stress amplitude (95-120 MPa) and stress rate (30-750 MPa/s) and tested specimens were characterized using transmission and scanning electron microscopy. The experimental results show that with the increase in mean stress and stress amplitude, the ratcheting strain accumulation increases with reduction in fatigue life. However, increase in stress rate leads to improvement in fatigue life of the material due to small ratcheting strain accumulation. Fractographs showed a decrease in area fraction of fatigue failed region.

Keywords: asymmetric cyclic loading, ratcheting fatigue, mean stress, stress amplitude, stress rate, plastic strain

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Authors: Sevil Kaynar Turkoglu, Jinde Zhang, Jo Ann Ratto, Hanna Dodiuk, Samuel Kenig, Joey Mead

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Superhydrophilic, crack-free thin film coatings based on silica nanoparticles were fabricated by dip-coating method. Both thermodynamic and dynamic effects on the wetting properties of the thin films were investigated by modifying the coating formulation via changing the particle-to-binder ratio and weight % of silica in solution. The formulated coatings were characterized by a number of analyses. Water contact angle (WCA) measurements were conducted for all coatings to characterize the surface wetting properties. Scanning electron microscope (SEM) images were taken to examine the morphology of the coating surface. Atomic force microscopy (AFM) analysis was done to study surface topography. The presence of hydrophilic functional groups and nano-scale roughness were found to be responsible for the superhydrophilic behavior of the films. In addition, surface chemistry, compared to surface roughness, was found to be a primary factor affecting the wetting properties of the thin film coatings.

Keywords: poly (acrylic acid), silica nanoparticles, superhydrophilic coatings, surface wetting

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Authors: N. Selami, M. Kaid Harche

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A pink-pigmented, aerobic, facultatively methylotrophic bacterium, was isolated from Retama monosperma root nodules and identified as a member of the genus Methylobacterium. Inoculation of R. monosperma plants by a pure culture of isolate strain under a hydroponic condition, resulted, 10 dpi, the puffiness at lateral roots. The observation in detail the anatomy and ultra-structure of infection sites by light and electron microscopy show that the bacteria induce stimulation of the division of cortical cells and digestion of epidermis cells then, Methylobacterium was observed in the inter and intracellular spaces of the outer cortex root. These preliminary results allow us to suggest the establishment of an epi-endosymbiotic interaction between Methylobacterium sp and R. monosperma.

Keywords: endophytic colonization, Methylobacterium, microscopy, nodule, pink pigmented, Retama monosperma

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Authors: Neda Sinaei, Davood Zare, Mehrdad Azin

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Polyhydroxyalkanoates (PHAs) are biocompatible and biodegradable polymers produced by a wide range of bacterial strains. These biopolymers are significantly studied for drug delivery and tissue engineering applications because of their fascinating physicochemical properties. Polyhydroxybutyrate (PHB) scaffold that has been extracted from a novel bacteria using oil wastewater was selected to study. Some physical parameters affecting scaffold properties such as PHB concentration, solvent evaporation speed, and ultrasonic time were investigated. Scanning electron microscopy was used to evaluate the porosity. Afterward, the biocompatibility of PHB scaffold was assessed. Initial results showed the highly porous PHB scaffold structure with a variety of pore sizes. Subsequent results indicated that more unique pore sizes can be obtained by optimizing physical factors. It would be noticed that the morphology of the pore structure was accordingly affected by ultrasonic time. Hence, In vitro cell viability tests on the PHB scaffold using human foreskin fibroblasts revealed strong cell attachment and proliferation supports. Therefore, it can be concluded that the cost-effective PHB scaffold has the potential using as a biomaterial cell adhesion substrate in therapeutic applications.

Keywords: Polyhydroxybutyrate, biocompatible, scaffold, porous, tissue engineering

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Authors: Sudkate Chaiyo, Weena Siangproh, Orawon Chailapakul, Kurt Kalcher

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In the present work, a simple and sensitive non-enzymatic electrochemical detection of glucose in disposable paper-based sensor was developed at ionic liquid/graphene/cobalt phthalocyanine composite (IL/G/CoPc) modified electrode. The morphology of the fabricated composite was characterized and confirmed by scanning electron microscopy and UV-Vis spectroscopy. The UV-Vis spectroscopy results confirmed that the G/CoPc composite formed via the strong π–π interaction between CoPc and G. Amperometric i-t technique was used for the determination of glucose. The response of glucose was linear over the concentration ranging from 10 µM to 1.5 mM. The response time of the sensor was found as 30 s with a limit of detection of 0.64 µM (S/N=3). The fabricated sensor also exhibited its good selectivity in the presence of common interfering species. In addition, the fabricated sensor exhibited its special advantages such as low working potential, good sensitivity along with good repeatability and reproducibility for the determination of glucose.

Keywords: glucose, paper-based sensor, ionic liquid/graphene/cobalt phthalocyanine composite, electrochemical detection

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Authors: Babak Sadeghi, Rony Snyders, Marie-Paule.Delplancke-Ogletree

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Nitrogen fixation (NF) is one of the crucial industrial processes. Many attempts have been made in order to artificially fix nitrogen, and among them, the Haber-Bosch’s (H-B) process is widely used. However, it presents two major drawbacks: huge fossil feedstock consumption and noticeable greenhouse gases emission. It is, therefore, necessary to develop alternatives. Plasma technology, as an inherent “green” technology, is considered to have a great potential for reducing the environmental impacts and improving the energy efficiency of the NF process. In this work, we have studied the catalyst assisted microwave plasma for NF application. Heterogeneous catalysts of MoO₃, with various loads 0, 5, 10, 20, and 30 wt%, supported on γ-alumina were prepared by conventional wet impregnation. Crystallinity, surface area, pore size, and microstructure were obtained by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption isotherm, Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The XRD patterns of calcined alumina confirm the γ- phase. Characteristic picks of MoO₃ could not be observed for low loads (< 20 wt%), likely indicating a high dispersion of metal oxide over the support. The specific surface area along with pores size are decreasing with increasing calcination temperature and MoO₃ loading. The MoO₃ loading does not modify the microstructure. TEM and SEM results for loading inferior to 20 wt% are coherent with a monolayer of MoO₃ on the support as proposed elsewhere. For loading of 20 wt% and more, TEM and Electron diffraction (ED) show nanocrystalline ₃-D MoO₃ particles. The catalytic performances of these catalysts were investigated in the post-discharge of a microwave plasma for NOx formation from N₂/O₂ mixtures. The plasma is sustained by a surface wave launched in a quartz tube via a surfaguide supplied by a 2.45 GHz microwave generator in pulse mode. In-situ identification and quantification of the products were carried out by Fourier-transform infrared spectroscopy (FTIR) in the post-discharge region. FTIR analysis of the exhausted gas reveal NO and NO₂ bands in presence of catalyst while only NO band were assigned without catalyst. On the other hand, in presence of catalyst, a 10% increase of NOₓ formation and of 20% increase in energy efficiency are observed.

Keywords: γ-Al2O₃-MoO₃, µ-waveplasma, N2 fixation, Plasma-catalysis, Plasma diagnostic

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Authors: Pajaree Donkhampa, Fuangfa Unob

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Ceftazidime is an antibiotic drug commonly used to treat several human and veterinary infections. However, the presence of ceftazidime residues in the environment may induce microbial resistance and cause side effects to humans. Therefore, monitoring the level of ceftazidime in environmental resources is important. In this work, a melamine foam platform was proposed for simultaneous extraction and colorimetric detection of ceftazidime based on the azo dye formation on the surface. The melamine foam was chemically modified with polyethyleneimine (PEI) and characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Ceftazidime is a sample that was extracted on the PEI-modified melamine foam and further reacted with nitrite in an acidic medium to form an intermediate diazonium ion. The diazotized molecule underwent an azo coupling reaction with chromotropic acid to generate a red-colored compound. The material color changed from pale yellow to pink depending on the ceftazidime concentration. The photo of the obtained material was taken by a smartphone camera and the color intensity was determined by Image J software. The material fabrication and ceftazidime extraction and detection procedures were optimized. The detection of a sub-ppm level of ceftazidime was achieved without using a complex analytical instrument.

Keywords: colorimetric detection, ceftazidime, melamine foam, extraction, azo dye

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Authors: Ezgi Yurdakul, Klaus-Alexander Rieder, Richard Sibbick

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Most of the shotcrete projects require compliance with meeting a specified early-age strength target (e.g., reaching 1 MPa in 1 hour) that is selected based on the underground conditions. To meet the desired early-age performance characteristics, accelerators are commonly used as they increase early-age strength development rate and accelerate the setting thereby reducing sagging and rebound. The selection of accelerator type and its dosage is made by the setting time and strength required for the shotcrete application. While alkaline and alkali-free accelerators are the two main types used in wet-mix shotcrete; alkali-free admixtures increasingly substitute the alkaline accelerators to improve the performance and working safety. This paper aims to evaluate the impact of alkali-free accelerators in wet-mix on various tests including set time, early and later-age compressive strength, boiled absorption, and electrical resistivity. Furthermore, the comparison between accelerated and non-accelerated samples will be made to demonstrate the interaction between cement and accelerators. Scanning electron microscopy (SEM), fluorescent resin impregnated thin section and cut and polished surface images will be used to understand the microstructure characterization of mixes in the presence of accelerators.

Keywords: accelerators, chemical admixtures, shotcrete, sprayed concrete

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Authors: Radia Imane Fertout

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In recent years, the reaction of dry reforming of methane (DRM) has attracted much attention due to its environmental and industrial importance. Various catalysts, including Ni-based catalysts, have been investigated for the DRM. Doping Ni/Al₂O₃ by lanthanum and alkaline earth element may strongly influence solid-state reaction and increases the stability of catalysts due to the lower density and high basicity of these oxides. The effect of SrO on the activity and stability of Ni/Al₂O₃-La₂O₃ in dry reforming of methane was investigated. These catalysts have been prepared with the impregnation method, calcined in air at 450 and 650°C, then characterized by BET surface area, X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques and tested in DRM. The results showed that the addition of strontium to Ni/Al2O₃-La₂O₃ decreased the specific surface area. XRD results revealed the presence of different phases of Al₂O₃, La(OH)₃, La₂O₂CO₃, and SrCO₃. The catalytic evaluation results showed that adding SrO increased the catalytic activity and stability, that explained by the strong basicity of strontium. SEM analysis after the reaction indicates the formation of carbon over the spent catalyst and that the addition of strontium stabilized the surface of the catalyst.

Keywords: dry reforming of methane, Ni/Al₂O₃-La₂O₃ catalyst, strontium, nickel

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Authors: Hesham Moustafa, Ahmed M. Youssef

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The demand for green packagingin the food field has been gained increasing attention in recent decades because of its degradability and safely. Thus, this study revealed that the by-product bagasse papers (BPs) derived from sugarcane waste can be decorated with a thin layer of polystyrene (PS) nanocomposites using the spreading approach.Three variable concentrations of TiO2 nanoparticles (i.e. 0.5, 1.0, 1.5 wt.%) were used to fabricate PS nanocomposites. The morphology of coated BP-PS biofilms was examined by X-ray diffraction, Fourier transferred Infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Moreover, other measurements such as mechanical, thermal stability, flammability, wettability by the contact angle, water vapor, and gas barrier properties were carried out on the fabricated BP-PS biofilms. Most outcomes showed that the major properties were enhanced when the PS nanocomposites were implemented. The use of 1.5 wt.% TiO2 in PS nanocomposite for coated BP-PS biofilm increased the tensile stress by ~ 217 % compared to uncoated BP film. Furthermore, the rate of burning for BP-PS-1.5% film was reduced to ~ 33 mm/min because of the crystallinity of PS and the barrier effect provided by TiO₂ NPs. These coated sheets provide a promising candidate for use in advanced packaging applications.

Keywords: bagasse paper, polystyrene nanocomposites, TiO2 nanoparticles, active packaging, mechanical properties, flammability

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Authors: Ahmed Farghali, Heba Amar, Mohamed Khedr

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NiAl-Layered Double Hydroxide (NiAl-LDH), one of anionic functional layered materials, has been prepared by a simple co-precipitation process. X-ray diffraction patterns confirm the formation of the desired compounds of NiAl hydroxide single phase and the crystallite size was found to be about 4.6 nm. The morphology of the prepared samples was investigated using scanning electron microscopy and the layered structure was appeared under the transmission electron microscope. The thermal stability and the function groups of NiAl-LDH were investigated using thermal gravimetric analysis (TGA) and Fourier transform infrared (FTIR) respectively. NiAl-LDH was investigated as a photo-catalyst for the degradation of some toxic dyes such as toluidine blue and bromopyrogallol red. It shows good catalytic efficiency in visible light and even in dark. For the first time NiAl-LDH was used for hydrogen storage application. NiAl-LDH samples were exposed to 20 bar applied hydrogen pressure at room temperature, 100 and -193 oC. NiAl-LDH samples appear to have feasible hydrogen storage capacity. It was capable to adsorb 0.1wt% at room temperature, 0.15 wt% at 100oC and storage capacity reached 0.3 wt% at -193 oC.

Keywords: NiAl-LDH, preparation, characterization, photo-catalysis, hydrogen storage

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Authors: Raghvendra Singh Yadav, Ivo Kuřitka, Jarmila Vilcakova, Pavel Urbanek, Michal Machovsky, Milan Masař, Martin Holek

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ZnFe2O4 spinel ferrite nanoparticles were synthesized by sol-gel auto-combustion method. The synthesized spinel ferrite nanoparticles were annealed at different higher temperature to achieve different size nanoparticles. The as synthesized and annealed samples were characterized by powder X-ray Diffraction Spectroscopy, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, UV-Vis absorption Spectroscopy and Scanning Electron Microscopy. The magnetic properties were studied by vibrating sample magnetometer. The variation in magnetic parameters was noticed with variation in grain size. The dielectric constant and dielectric loss with variation of frequency shows normal behaviour of spinel ferrite. The variation in conductivity with variation in grain size is noticed. Modulus and Impedance Spectroscopy shows the role of grain and grain boundary on the electrical resistance and capacitance of different grain sized spinel ferrite nanoparticles. Acknowledgment: This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic – Program NPU I (LO1504).

Keywords: spinel ferrite, nanoparticles, magnetic properties, dielectric properties

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Authors: K. Raza, S. Gul, M. Ali

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Concrete is a fundamental building material, extensively utilized by the construction industry. Problems related to the strength of concrete is an immense issue for the sustainability of concrete structures. Concrete mostly loses its strength due to the cracks produced in it by shrinkage or hydration process. This study aims to enhance the strength and service life of the concrete structures by incorporating bio-based admixture in the concrete. By the injection of bio-based admixture (BBA) in concrete, it will self-heal the cracks by producing calcium carbonate. Minimization of cracks will compact the microstructure of the concrete, due to which strength will increase. For this study, Bacillus subtilis will be used as a bio-based admixture (BBA) in concrete. Calcium lactate up to 1.5% will be used as the food source for the Bacillus subtilis in concrete. Two formulations containing 0 and 5% of Bacillus subtilis by weight of cement, will be used for the casting of concrete specimens. Direct mixing method will be adopted for the usage of bio-based admixture in concrete. Compressive strength test will be carried out after 28 days of curing. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) will be performed for the examination of micro-structure of concrete. Results will be drawn by comparing the test results of 0 and 5% the formulations. It will be recommended to use to bio-based admixture (BBA) in concrete for columns because of the satisfactory increase in the compressive strength of concrete.

Keywords: bio-based admixture, Bacillus subtilis, calcium lactate, compressive strength

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Authors: Lukas Munster, Pavel Bazant, Ivo Kuritka

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Zinc oxide sub-micro particles and metallic silver nano particles (Ag/ZnO) were deposited on micro crystalline cellulose surface by a fast, simple and environmentally friendly one-pot microwave assisted solvo thermal synthesis in an open vessel system equipped with an external reflux cooler. In order to increase the interaction between the surface of cellulose and the precipitated Ag/ZnO particles, oxidized form of cellulose (cellulose dialdehyde, DAC) prepared by periodate oxidation of micro crystalline cellulose was added to the reaction mixture of Ag/ZnO particle precursors and untreated micro crystalline cellulose. The structure and morphology of prepared hybrid powder materials were analysed by X-ray diffraction (XRD), energy dispersive analysis (EDX), scanning electron microscopy (SEM) and nitrogen absorption method (BET). Microscopic analysis of the prepared materials treated by ultra-sonication showed that Ag/ZnO particles deposited on the cellulose/DAC sample exhibit increased adhesion to the surface of the cellulose substrate which can be explained by the DAC adhesive effect in comparison with the material prepared without DAC addition.

Keywords: microcrystalline cellulose, microwave synthesis, silver nanoparticles, zinc oxide sub-microparticles, cellulose dialdehyde

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Authors: Said Nurdin, Fatimah A. Misebah, Rosli M. Yunus, Mohd S. Mahmud, Ahmad Z. Sulaiman

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The discarded clam shell waste, fossil and edible oil as biolubricant feedstocks create environmental impacts and food chain dilemma, thus this work aims to circumvent these issues by using activated saltwater clam shell waste (SCSW) as solid catalyst for conversion of Jatropha curcas oil as non-edible sources to ester biolubricant. The characterization of solid catalyst was done by Differential Thermal Analysis-Thermo Gravimetric Analysis (DTA-TGA), X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transformed Infrared Spectroscopy (FTIR) analysis. The calcined catalyst was used in the transesterification of Jatropha oil to methyl ester as the first step, and the second stage was involved the reaction of Jatropha methyl ester (JME) with trimethylolpropane (TMP) based on the various process parameters. The formated biolubricant was analyzed using the capillary column (DB-5HT) equipped Gas Chromatography (GC). The conversion results of Jatropha oil to ester biolubricant can be found nearly 96.66%, and the maximum distribution composition mainly contains 72.3% of triester (TE).

Keywords: conversion, Jatropha curcas oil, ester biolubricant, solid catalyst

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Authors: Sergei Zhevnenko

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Сontinuous layer of tantalum boride is formed on the surface as a result of reactive wetting of oxidized tantalum by copper melt with boron at a temperatures above 1150 °C. An increase in the wetting temperature above 1400 °C leads to a change in the formation mechanism of tantalum borides, they are formed in the nanosized flakes. In the presented work, we studied the process of copper-based in-situ composite formation, strengthened by the particles of tantalum borides. We investigated the structure of the formed particles, the conditions, and the kinetics of their formation. Dissolving boride particles do not have time to mix uniformly in the melt upon sufficiently rapid cooling and form a macrostructure, partly repeating the shape of the metallic tantalum. This allows to set different gradient structures in the copper alloy. Such macrostructures have been obtained. Boride particles and microstructures were studied by scanning and transmission electron microscopy, and regions with particles were investigated by nanoindentation. In this work, we also measured the kinetics of impregnation of porous tantalum with copper-boron melt and studied the structures of the composite, in which the melt filling the interpore space is saturated with boride particles.

Keywords: copper, tantalum borides, in-situ composites, wetting, imbibition

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Authors: Olaitan Akanji, Cleophas Loto, Patricia Popoola, Andrei Kolesnikov

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Studies involving performance of corrosion inhibitors had been identified as one of the critical research needs for improving the durability of mild steel used in various industrial applications. This paper investigates the inhibiting effect of calcium gluconate against the corrosion of mild steel in 2.5M magnesium chloride using weight loss method and linear polarization technique, calculated corrosion rates from the obtained weight loss data, potentiodynamic polarization measurements are in good agreement. Results revealed calcium gluconate has strong inhibitory effects with inhibitor efficiency increasing with increase in inhibitor concentration at ambient temperature, the efficiency of the inhibitor increased in the following order of concentrations 2%g/vol,1.5%g/vol,1%g/vol,0.5%g/vol. Further results obtained from potentiodynamics experiments had good correlation with those of the gravimetric methods, the adsorption of the inhibitor on the mild steel surface from the chloride has been found to obey Langmuir, Frumkin and Freudlich adsorption isotherm. Scanning electron microscopy (SEM) observation confirmed the existence of an absorbed protective film on the metal surface.

Keywords: calcium gluconate, corrosion, magnesium chloride, mild steel

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Authors: Amel Asselah, Nadia Chabli, Imane Haddad

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The adsorption of methylene blue and congo red dyes in an aqueous solution, on a food waste adsorbent: potato peel, and on a commercial adsorbent: activated carbon powder, was investigated using batch experiments. The objective of this study is the valorization of potato peel by its application in the elimination of these dyes. A comparison of the adsorption efficiency with a commercial adsorbent was carried out. Characterization of the potato peel adsorbent was performed by scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy, Fourier transforms infrared spectroscopy, X-ray diffraction, and X-ray fluorescence. Various parameters were analyzed, in particular: the adsorbent mass, the initial dye concentration, the contact time, the pH, and the temperature. The results reveal that it is about 98% for methylene blue-potato peel, 84% for congo red-potato peel, 84% for methylene blue-activated carbon, and 66% for congo red-activated carbon. The kinetic data were modeled by different equations and revealed that the adsorption of textile dyes on adsorbents follows the model pseudo-second-order, and the particular extra diffusion governs the adsorption mechanism. It has been found that the adsorption process could be described by the Langmuir isotherm.

Keywords: bioadsorbent, waste valorization, adsorptio, textile dyes

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Authors: Budi Hastuti, Mudasir, Dwi Siswanta, Triyono

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Biosorbent, such as pectin and chitosan, are usually produced with low physical stability, thus the materials need to be modified. In this research, the physical characteristic of adsorbent was increased by grafting chitosan using acetate carboxymetyl chitosan (CC). Further, CC and Pectin (Pec) were crosslinked using cross-linking agent BADGE (bis phenol A diglycidyl ether) to get CC-Pec-BADGE (CPB) adsorbent. The cross-linking processes aim to form stable structure and resistance on acidic media. Furthermore, in order to increase the adsorption capacity in removing Pb(II), the adsorbent was added with NaCl to form macroporous adsorbent named CCPec-BADGE-Na (CPB-Na). The physical and chemical characteristics of the porogenic adsorbent structure were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The adsorption parameter of CPB-Na to adsorb Pb(II) ion was determined. The kinetics and thermodynamics of the bath sorption of Pb(II) on CPB-Na adsorbent and using chitosan and pectin as a comparison were also studied. The results showed that the CPB-Na biosorbent was stable on acidic media. It had a rough and porous surface area, increased and gave higher sorption capacity for removal of Pb(II) ion. The CPB-Na 1/1 and 1/3 adsorbent adsorbed Pb(II) with adsorption capacity of 45.48 mg/g and 45.97 mg/g respectively, whereas pectin and chitosan were of 39.20 mg /g and 24.67 mg /g respectively.

Keywords: porogen, Pectin, Carboxymethyl Chitosan (CC), CC- Pec-BADGE-Na

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Authors: Gichun Cha, Byoungjoon Yu, Jihwan Park, Minsoo Park, Junghyun Im, Sehwan Park, Sujung Sin, Seunghee Park

Abstract:

The goal of this research is to estimate a structural shape change using terrestrial laser scanning. This study proceeds with development of data reduction and shape change estimation algorithm for large-capacity scan data. The point cloud of scan data was converted to voxel and sampled. Technique of shape estimation is studied to detect changes in structure patterns, such as skyscrapers, bridges, and tunnels based on large point cloud data. The point cloud analysis applies the octree data structure to speed up the post-processing process for change detection. The point cloud data is the relative representative value of shape information, and it used as a model for detecting point cloud changes in a data structure. Shape estimation model is to develop a technology that can detect not only normal but also immediate structural changes in the event of disasters such as earthquakes, typhoons, and fires, thereby preventing major accidents caused by aging and disasters. The study will be expected to improve the efficiency of structural health monitoring and maintenance.

Keywords: terrestrial laser scanning, point cloud, shape information model, displacement measurement

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Authors: Ella C. Linganiso, Bonex W. Mwakikunga, Trilock Singh, Sanjay Mathur, Odireleng M. Ntwaeaborwa

Abstract:

The use of nanostructured semiconducting material to catalyze degradation of environmental pollutants still receives much attention to date. One of the desired characteristics for pollutant degradation under ultra-violet visible light is the materials with extended carrier charge separation that allows for electronic transfer between the catalyst and the pollutants. In this work, zinc oxide n-type semiconductor vertically aligned structures were fabricated on silicon (100) substrates using the chemical bath deposition method. The as-synthesized structures were treated with nickel and sulphur. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy were used to characterize the phase purity, structural dimensions and elemental composition of the obtained structures respectively. Photoluminescence emission measurements showed a decrease in both the near band edge emission as well as the defect band emission upon addition of nickel and sulphur with different concentrations. This was attributed to increased charger-carrier-separation due to the presence of Ni-S material on ZnO surface, which is linked to improved charge transfer during photocatalytic reactions.

Keywords: Carrier-charge-separation, nickel, photoluminescence, sulphur, zinc oxide

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Authors: Renu Kumari, Jyotsna Dutta Majumdar

Abstract:

In the present study, composite coating consisting of hydroxyapatite (HA) + 50 wt% TiO2 has been developed on Ti-6Al-4V substrate by plasma spray deposition technique. Followed by plasma spray deposition, detailed surface roughness and microstructural characterization were carried out by using optical profilometer and scanning electron microscopy (SEM), respectively. The composition and phase analysis were carried out by energy-dispersive X-ray spectroscopy analysis, and X-ray diffraction (XRD) technique, respectively. The bio-activity behavior of the uncoated and coated samples was also compared by dipping test in Hank’s solution. The average surface roughness of the coating was 10 µm (as compared to 0.5 µm of as-received Ti-6Al-4V substrate) with the presence of porosities. The microstructure of the coating was found to be continuous with the presence of solidified splats. A detailed XRD analysis shows phase transformation of TiO2 from anatase to rutile, decomposition of hydroxyapatite, and formation of CaTiO3 phase. Standard dipping test confirmed a faster kinetics of deposition of calcium phosphate in the coated HA+50% wt.% TiO2 surface as compared to the as-received substrate.

Keywords: titanium, plasma spraying, microstructure, bio-activity, TiO2, hydroxyapatite

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Authors: Bertalan Jillek, Péter Szabó, Judit Kopniczky, István Szabó, Balázs Patczai, Kinga Turzó

Abstract:

Hip and knee prostheses are one of the most frequently used medical implants, that can significantly improve patients’ quality of life. Long term success and biointegration of these prostheses depend on several factors, like bulk and surface characteristics, construction and biocompatibility of the material. The applied surgical technique, the general health condition and life-quality of the patient are also determinant factors. Medical devices used in orthopedic surgeries have different surfaces depending on their function inside the human body. Surface roughness of these implants determines the interaction with the surrounding tissues. Numerous modifications have been applied in the recent decades to improve a specific property of an implant. Our goal was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology. Morphological and chemical structure of Vortex plate anodized titanium, cemented THR (total hip replacement) stem high nitrogen REX steel (SS), uncemented THR stem and cup titanium (Ti) alloy with titanium plasma spray coating (TPS), cemented cup and uncemented acetabular liner HXL and UHMWPE and TKR (total knee replacement) femoral component CoCrMo alloy (Sanatmetal Ltd, Hungary) discs were examined. Visualization and elemental analysis were made by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. SEM and AFM revealed the morphological and roughness features of the examined materials. TPS Ti presented the highest Ra value (25 ± 2 μm, followed by CoCrMo alloy (535 ± 19 nm), Ti (227 ± 15 nm) and stainless steel (170 ± 11 nm). The roughness of the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements on the investigated prosthesis materials: Vortex plate Ti (Ti, O, P); TPS Ti (Ti, O, Al); SS (Fe, Cr, Ni, C) CoCrMo (Co, Cr, Mo), HXL (C, Al, Ni) and UHMWPE (C, Al). The results indicate that the surface of prosthesis materials have significantly different features and the applied investigation methods are suitable for their characterization. Contact angle measurements and in vitro cell culture testing are further planned to test their surface energy characteristics and biocompatibility.

Keywords: morphology, PE, roughness, titanium

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Authors: A. Asselah, A. Khalfi, M. A.Toumi, A.Tazerouti

Abstract:

The study of the corrosion inhibition of a standard carbon steel "API 5L grade X70" by two biodegradable anionic surfactants derived from fatty acids by photo sulfochlorination, called sodium lauryl methyl ester sulfonates and sodium palmityl methyl ester sulfonates was carried. A solution at 2.5 g/l NaCl saturated with carbon dioxide is used as a corrosive medium. The gravimetric and electrochemical technics (stationary and transient) were used in order to quantify the rate of corrosion and to evaluate the electrochemical inhibition efficiency, thus the nature of the mode of action of the inhibitor, in addition to a surface characterization by scanning electron microscopy (MEB) coupled to energy dispersive X-ray spectroscopy (EDX). The variation of the concentration and the temperature were examined, and the mode of adsorption of these inhibitors on the surface of the metal was established by assigning it the appropriate isotherm and determining the corresponding thermodynamic parameters. The MEB-EDX allowed the visualization of good adhesion of the protective film formed by the surfactants to the surface of the steel. The corrosion inhibition was evaluated at around 93% for sodium lauryl methyl ester sulfonate surfactant at 20 ppm and 87.2% at 50 ppm for sodium palmityl methyl ester sulfonate surfactant.

Keywords: carbon steel, oilfield, corrosion, anionic surfactants

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Authors: Osama Saber

Abstract:

Cyanate is one such anion which is produced during protein poisoning in the body and has been studied extensively in the field of biochemistry because of its toxicity. The present work aims at confinement and storage of cyanate in the nano scale. It was achieved through the intercalation of cyanate anions into nanolayerd structures of Ni-Al LDH. In addition, the effect of aging time on the intercalation of cyanate was clarified using X-ray diffraction and scanning electron microscopy. Furthermore, the effect of cations on the affinity towards the intercalation of cyanate anions inside LDH structure was studied by replacement of tetra-valent cations Ti4+ instead of the tri-vallent cations Al3+ during the preparation of LDH structure. X-ray diffraction patterns of the Ni-Ti LDH showed that the interlayer spacing was 0.73 nm. This spacing was smaller than that of Ni-Al LDH suggesting that the interlayered anions into Ni-Ti LDH are different from those into Ni-Al LDH. Thermal analyses (TG, DTG, and DTA) and Infra-red spectra revealed the presence of only cyanate anions into Ni-Ti LDH while, in the case of Ni-Al LDH, both cyanate and carbonate anions were observed. SEM images showed plate-like morphology for both Ni-Ti and Ni-Al LDHs although the shapes of their plates are not similar. Our results suggested that the LDH structures containing titanium cations have higher affinity for cyanate anions than those containing aluminum cations. Therefore, this choice for cyanate in the interlayered spacing widens the applicability to study the effect of the confinement on the toxicity of cyanate by bio researchers.

Keywords: nanolayered structures, Ni-Al LDH, Ni-Ti LDH, intercalation of cyanate anions, urea hydrolysis

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