This paper presents the study of mechanical properties of short random oil palm fibre reinforced epoxy (OPF/epoxy) composites. Empty fruit bunch (EFB) was selected as the fibre and epoxy as the matrix. Composite plate with four different volume fractions of oil palm fibre was fabricated, (5 vol%, 10 vol%, 15 vol% and 20 vol%). The fabrication was made by hand-lay up techniques. The tensile and flexural properties showed a decreasing trend as the fibre loading was increased. The highest tensile properties was obtained for the composite with fibre loading of 5 vol% and there were no significant effect for addition of more than 5 vol% to the flexural properties. Interaction between fibre and matrix was observed from the scanning electron microscope (SEM) micrograph.
In this study TiO2 films have been prepared using two different techniques i.e. sol-gel and electron gun evaporation (e-gun) techniques. The films were annealed at 300, 350 and 400oC in air. The microstructure study using field emission scanning electron microscope and x-ray diffractometer showed nanometer grains size and only the film prepared by sol-gel and annealed at 400oC has anatase phase while others are amorphous. To study the effect of the films (as buffer layer) onto the dielectric bolometer Ba0.6Sr 0.4TiO3 as distance sensor, sensors with the configuration of Al/BST/TiO2/RuO2/SiO2/Si were built. Two different measurements i.e. with and without infrared source were carried out to measure the sensitivity and repeatability of the sensors. The sensors which contained sol-gel TiO2 films gave reading for both type of measurements, indicating that the sensor can act as active and passive sensors. However, the sensors which contained e-gun TiO2 films only gave responses when the IR source was used, indicating that they can only act as passive sensors. The most sensitive sensor was TiO2 film prepared by sol gel and annealed at 350oC. In general sensors which contained TiO2 films prepared by sol gel showed good repeatability.
In this work, the preparation of ZnO, N-doped ZnO (NZO), Al-doped ZnO (AZO) and Al, N-doped ZnO (ANZO) thin films by the sol-gel spin-coating method is reported. The structural properties and surface morphologies of films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The XRD and SEM results disclosed that the crystallization quality and grain size of as-prepared films were highly influenced by N and Al doping. UV-VIS spectrophotometer results indicated that Al and N additives could significantly enhance the optical transparency and induce the blue-shift in optical bandgap of ZnO films.
CaxZn(1_x)Al204thin films (x = 0.00; 0 .05 ; 0.10; 0.15 and 0.20) were prepared by sol-gel method with the substitution of Zn2+ by Ca" in the framework of ZnAl204. The effect of Ca addition on the structure and morphology of CaZnAl204thin films was investigated by x-ray diffraction (xRD), field-emission scanning electron microscope (FESEM), energy-dispersive x-ray spectroscopy (EDx), ultra-violet visible (uv-Vis) and atomic force microscope (AFM). The xRD patterns showed the characteristic peaks of face-centred cubic (fcc)ZnAl204and CaZnAl204. The addition of Ca increased the crystallite size from 8.9 to 302 nm. The bandgap of CaxZnuld204 thin film was found in the range of 3.40 to 3.84 eV. sEm micrograph shows the morphology of all thin films is sphere-like, with the grain size increased from 33 to 123 nm. The AFM images show the roughness of surface morphology increased. The substitution of Zn2+ by Ca" increased the crystallite size, grain size and surface roughness which evidently increased the density (4.59 to 4.64 glcm3) and dielectric constant (8.48 to 9.54). The composition of CaxZn(1_x)Al204is considered as suitable material for GPS patch antennas.
A clear understanding on the fundamental mechanism in solid state self-healing resin system might significantly improve the optimization of healing performance. The focus of this study was to prove the diffusion (through thermal inter-diffusion) of a linear healing agent within the network matrix resin. The results had demonstrated that 45 to 21 percentage recoveries in fracture toughness (K1C) were observed within the third healing cycles of the healable resin. Based on the optical microscopy, scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIM) analyst; the diffusion of healing agent was also demonstrated by the change in the morphology and chemical images of the healing agent on the fracture surface specimen, before and after healing process.
Electrospinning is a promising approach to fabricate desirable electropsun nanofibrous scaffold that could be applied in the medical fields. In this study, bacterial copolymer poly(3-hydroxybutyrate-co-68 mol% 4-hydroxybutyrate) [P(3HB-co-68mol% 4HB)] copolymer produced was fabricated into electrospun nanofibers using various combination of electrospinning parameters including the polymer solution, applied voltage and injection speed. The morphology of the fabricated scaffolds were observed using scanning electron microscope (SEM). The SEM images were analysed for the fibre diameter distribution of the scaffolds using Image Analyser. The results revealed that the 8 wt% of polymer solution, 25 kV/cm of the applied voltage and 1.5 mL/h of the injection speed was the most suitable combination. This electrospinning parameters combination fabricated nanofibrous P(3HB-co-4HB) scaffold with smooth, beadles and uniform nanofibers with small fibre diameter distribution.
The photodegradation rate constant and surface morphology of poly(vinyl chloride), upon irradiation with ultraviolet light was investigated in the presence of polyphosphates as photostabilizers. Poly(vinyl chloride) photodegradation rate constant was lower for the films containing polyphosphates compared to the blank film. In addition, the surface morphology of the irradiated poly(vinyl chloride) containing polyphosphates, examined by scanning electron microscopy, indicates that the surface was much smoother compared to the blank film.
The mechanical properties of Dual Phase Steel (DPS)-duplex structure-produced by quenching in pre-heated bitumen have been investigated. Medium carbon steels intercritically heated at different temperatures and holding times were quenched in hot bitumen. Optical and scanning electron microscopy characterisation of the duplex structure showed extensive network of fibrous martensite in a ferritic matrix with occasional presence of polygonal martensite. The duplex phase structure exhibited continuous yielding dynamics, improving the tensile and hardness values by about 42 and 35%, respectively, relative to the normalised structure. But, the elongation and impact values decreased by about 42 and 50%, respectively, when compared to the normalised structure. These values are similar to those obtained in duplex structure produced using conventional oil quenching. The tensile fractured surface showed transition between a predominantly cleavage mode in the lower annealing temperature to a mixed mode in the upper bound of the annealing temperature. These findings suggest that pre-heated bitumen can be exploited for the production of DPSs.
This research was carried out to study the effects of kenaf loading and alkaline treatment on tensile properties, density,
thermal and morphological properties of kenaf filled natural rubber latex foam (NRLF). Samples were prepared using a
Dunlop method. From the results, increasing loading of kenaf reduced the tensile strength and elongation at break for
both samples, treated and untreated kenaf filled NRLF. Meanwhile, modulus at 100% elongation and density increased
with an increased in kenaf loading. Samples with treated kenaf showed higher tensile strength, modulus at 100%
elongation and density but low in elongation at break as compared with samples with untreated kenaf. Thermal study
by using thermogravimetric analysis (TGA) showed that thermal stability reduced with increased in kenaf loading for
both samples. Samples with treated kenaf have higher thermal stability compared with samples of untreated kenaf. The
filler-matrix interaction and the pores size variation of both samples was clearly seen in the micrograph images by using
scanning electron microscope (SEM).
The Rhoptrobothriidae are one of the more enigmatic families of cestodes of elasmobranchs. Opinions on the taxonomic status of the familys three original genera (i.e., Myzophyllobothrium, Rhoptrobothrium, and Myzocephalus) have varied over the 115 years since they were erected. Some authors have considered all three valid, others have considered Rhoptrobothrium to be a synonym of Myzopyllobothrium or a genus inquirendum, yet others have considered Myzocephalus to be a synonym of the phyllobothriid genus Thysanocephalum. All three genera were established for specimens collected from eagle rays off Sri Lanka. The erection of Mixophyllobothrium for two specimens from a cowtail stingray off India three decades ago added additional confusion to the situation, with some authors considering it valid and others a synonym of Myzocephalus. These disagreements stem largely from differences in interpretation of the complex morphology of the scolex of members of these genera. Furthermore, with the exception of Rhoptrobothrium comprising four species, each genus is monotypic. All but Rhoptrobothrium has not been considered in detail for nearly a century, largely because of a lack of available material. The taxonomic status of these genera is assessed here based on light and scanning electron microscopy, and molecular data generated from new material collected from eagle rays off Indonesian and Malaysian Borneo, Japan, Sri Lanka, and Viet Nam. Morphological work indicates that the genera differ largely only in the degree of folding of the four remi that extend from the cephalic peduncle. A molecular phylogeny based on sequence data for the D1D3 region of the 28S rRNA gene, which include new data for eight specimens of four species, indicates that Myzophyllobothrium, Myzocephalus, and Rhoptrobothrium are not mutually monophyletic. The latter two genera and Mixophyllobothrium are considered synonyms of Myzophyllobothrium and five species are transferred to that genus. Myzophyllobothrium okamuri n. comb. is considered a species inquirendum. Myzophyllobothrium nagasawai n. sp. is described from Aetobatus narutobiei off Japan. Myzophyllobothrium narinari n. comb. is re-described based on newly collected cestodes from the type host and locality (i.e., Aetobatus ocellatus off Sri Lanka). Despite consisting of only a single genus, the family status of the group is retained in recognition of the unusual configuration of the scolex, which bears four biloculate bothridia and four remi extending from the cephalic peduncle. The ordinal placement of the family remains uncertain, but affinities with the Phyllobothriidea, rather than Tetraphyllidea are considered.
This study involves extraction of sulfated polysaccahride (SP) from brown seaweed (Turbinaria turbinata). Eight processing conditions affecting enzyme aided extraction (EAE) were screened using Plackett-Burman design. Three significant factors (hydrolysis time, enzyme concentration and extraction stage) were optimized using Faced Centred Central Composite Design in Random Surface Methods. Micrograph obtained using Field Emission Scanning Electron Microscopy revealed that cellulase degradation ruptured the seaweed cell matrix thus caused increase in the release of SP. The optimum conditions for extraction of SP from T. turbinata are: extraction stage of 2, hydrolysis time of 19.5 h and enzyme concentration of 1.5 μl/ml to produce 25.13% yield. The SP obtained from cellulase treated T. turbinata is a suitable anti-inflammatory agent for pharmaceutical applications.
In this study, compatibilizing effects of caprolactam-maleic anhydride (CL-MAH) and
polyethylene-grafted-maleic anhydride (PE-g-MAH) with different blend compositions on polymer
blends of recycled high density polyethylene (RHDPE) and ethylene vinyl acetate (EVA) blends were
investigated by tensile properties and swelling behavior. The use of CL-MAH improved the
compatibility of RHDPE80/EVA20 blend composition, and tensile properties of the resultant blend
compared well with those of RHDPE/EVA blends. Addition of PE-g-MAH improved the tensile
properties of RHDPE/EVA/PE-g-MAH blends than RHDPE/EVA blends without compatibilizer. The
scanning electron microscopy (SEM) morphologies of fracture surface for RHDPE/EVA blends with
presence of compatibilizers showing better incorporation of two different phases of polymer matrix.
This study reports on the synthesis of bi-metal compound (BMC) adsorbents based on commercial coconut activated carbon (CAC), surface-modified with metal acetate (ZnAc2), metal oxide (ZnO), and the basic compounds potassium hydroxide (KOH) and sodium hydroxide (NaOH). The adsorbents were then characterized by scanning electron microscopy and elemental analysis, microporosity analysis through Brunauer-Emmett-Teller (BET) analysis, and thermal stability via thermogravimetric analysis. Adsorption-desorption test was conducted to determine the adsorption capacity of H2S via 1 L adsorber and 1000 ppm H2S balanced 49.95% for N2 and CO2. Characterization results revealed that the impregnated solution homogeneously covered the adsorbent surface, morphology, and properties. The adsorption test result reveals that the ZnAc2/ZnO/CAC_B had a higher H2S breakthrough adsorption capacity and performed at larger than 90% capability compared with a single modified adsorbent (ZnAc2/CAC). Therefore, the synthesized BMC adsorbents have a high H2S loading, and the abundance and low cost of CAC may lead to favorable adsorbents in H2S captured.
Biofilms are adherent, multi-layered colonies of bacteria that are typically more resistant to the host immune response and routine antibiotic therapy. HA biomaterial comprises of a single-phased hydroxyapatite scaffold with interconnected pore structure. The device is designed as osteoconductive space filler to be gently packed into bony voids or gaps following tooth extraction or any surgical procedure. Gentamycin-coated biomaterial (locally made hydroxyapatite) was evaluated to reduce or eradicate the biofilm on the implant materials. The results indicated that the HA coated with gentamycin was biocompatible to human osteoblast cell line and the biofilm has been reduced after being treated with different concentrations of gentamycin-coated hydroxyapatite (HA).
Anionic surfactants are one of the pollutants derived from particulate matter (PM) and adversely affect the health of living organisms. In this study, the compositions of surfactants extracted from PM and vehicle soot collected in an urban area were investigated. A high-volume air sampler was used to collect PM sample at urban area based on coarse (> 1.5 µm) and fine (electron microscope. Results revealed that the MBAS concentration was dominated by fine mode particles (6.03 ± 3.97 µmol g-1), whereas heavy-duty vehicles, such as buses, demonstrated the highest surfactant concentration with an average value of 0.340 ± 0.180 µmol g-1. The structure of collected PM for all samples mostly appeared to be an irregular shape with the size range of ultrafine particles (0.05-0.2 µm). The emission of surfactants from diesel and petrol vehicles, especially at urban areas, should be a major concern, because they could negatively affect human health and the environment.
The present study investigated the biosorption capacity of live and dead cells of a novel Bacillus strain for chromium. The optimum biosorption condition was evaluated in various analytical parameters, including initial concentration of chromium, pH, and contact time. The Langmuir isotherm model showed an enhanced fit to the equilibrium data. Live and dead biomasses followed the monolayer biosorption of the active surface sites. The maximum biosorption capacity was 20.35 mg/g at 25 °C, with pH 3 and contact time of 50 min. Strain 139SI was an excellent host to the hexavalent chromium. The biosorption kinetics of chromium in the dead and live cells of Bacillus salmalaya (B. salmalaya) 139SI followed the pseudo second-order mechanism. Scanning electron microscopy and fourier transform infrared indicated significant influence of the dead cells on the biosorption of chromium based on cell morphological changes. Approximately 92% and 70% desorption efficiencies were achieved using dead and live cells, respectively. These findings demonstrated the high sorption capacity of dead biomasses of B. salmalaya 139SI in the biosorption process. Thermodynamic evaluation (ΔG⁰, ΔH⁰, and ΔS⁰) indicated that the mechanism of Cr(VI) adsorption is endothermic; that is, chemisorption. Results indicated that chromium accumulation occurred in the cell wall of B. salmalaya 139SI rather than intracellular accumulation.
Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm(-2), in contrast to MnO2, which produced a maximum power density of 9.2 mW cm(-2). The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms.
Hierarchical Si/ZnO trunk-branch nanostructures (NSs) have been synthesized by hot wire assisted chemical vapor deposition method for trunk Si nanowires (NWs) on indium tin oxide (ITO) substrate and followed by the vapor transport condensation (VTC) method for zinc oxide (ZnO) nanorods (NRs) which was laterally grown from each Si nanowires (NWs). A spin coating method has been used for zinc oxide (ZnO) seeding. This method is better compared with other group where they used sputtering method for the same process. The sputtering method only results in the growth of ZnO NRs on top of the Si trunk. Our method shows improvement by having the growth evenly distributed on the lateral sides and caps of the Si trunks, resulting in pine-leave-like NSs. Field emission scanning electron microscope image shows the hierarchical nanostructures resembling the shape of the leaves of pine trees. Single crystalline structure for the ZnO branch grown laterally from the crystalline Si trunk has been identified by using a lattice-resolved transmission electron microscope. A preliminary photoelectrochemical (PEC) cell testing has been setup to characterize the photocurrent of sole array of ZnO NR growth by both hydrothermal-grown (HTG) method and VTC method on ITO substrates. VTC-grown ZnO NRs showed greater photocurrent effect due to its better structural properties. The measured photocurrent was also compared with the array of hierarchical Si/ZnO trunk-branch NSs. The cell with the array of Si/ZnO trunk-branch NSs revealed four-fold magnitude enhancement in photocurrent density compared with the sole array of ZnO NRs obtain from VTC processes.
In this study, HA is superplastically embedded into Titanium substrate and the sample is subsequently deformed superplastically until 70% deformation degree. The former process is termed as superplastic embedment (SPE) while the later as superplastic deformation (SPD). After the SPE, HA is successfully embedded into the substrate, forming a layer with a thickness of about 249 nm. After the SPD the embedded HA layer thickness decreases to 111 nm. The SPD sample is then immersed in simulated body fluid (SBF) to evaluate its biological properties. A newly grown apatite is formed as a result of the immersion and the HA layer thickness increases with immersion time. The cohesion and adhesion strength within the HA coating and coating-substrate interface of the SPD samples before and after immersion in the SBF is evaluated through the nanoscratch test technique. The results indicate that the HA layer after SPD is still strong even though after being exposed in SBF environment for quite some time. The study suggests that the superplastically embedded HA nanolayer is still intact mechanically and functioning appropriately as biological activity base even after the SPD process.
Morphological and phenotypical signs of cultured readaptation osteoblasts were studied after a short-term space mission. The ultrastructure and phenotype of human osteoblasts after Soyuz TMA-11 space flight (2007) were evaluated by scanning electron microscopy, laser confocal microscopy, and ELISA. The morphofunctional changes in cell cultures persisted after 12 passages. Osteoblasts retained the drastic changes in their shape and size, contour deformation, disorganization of the microtubular network, redistribution of organelles and specialized structures of the plasmalemma in comparison with the ground control cells. On the other hand, the expression of osteoprotegerin and osteocalcin (bone metabolism markers) increased; the expression of bone resorption markers ICAM-1 and IL-6 also increased, while the expression of VCAM-1 decreased. Hence, space flight led to the development of persistent shifts in cultured osteoblasts indicating injuries to the cytoskeleton and the phenotype changes, indicating modulation of bone metabolism biomarkers.