Scanning electron microscope (SEM) images of two dust mites, Sturnophagoides brasiliensis and Sturnophagoides halterophilus, are presented to provide an improved visualization of the taxonomic characters of these mites. Sturnophagoides halterophilus can be differentiated from S. brasiliensis by their expanded genu and femur of leg I. The differences in morphology of male and female S. brasiliensis are also discussed.
Reduced susceptibility in Burkholderia pseudomallei during carbapenem therapy may lead to treatment failure. We isolated a clinical strain that had developed reduced susceptibility to carbapenems while on treatment. After reviewing the patient's clinical notes, the initial isolate (BUPS01/14) was exposed to carbapenem in vitro to mimic the clinical scenario. The stability of susceptibility of the carbapenem-exposed strain (BUPS01/14R) was examined by serial subculture in antibiotic-free broth. Biochemical and morphological comparison was performed by the VITEK® system and electron microscopy. MICs increased 32-fold following carbapenem exposure and became stable in the antibiotic-free environment. On electron microscopic examination, the BUPS01/14R cells were smoother and less wrinkled compared to BUPS01/14 cells. This report highlights a potential anti-melioidosis treatment failure due to the emergence of resistance while on carbapenem monotherapy. Further study of this strain is necessary to understand the mechanism of resistance at a molecular level.
We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37-1.47 eV.
In this paper, densification of in-situ copper-niobium carbide composite using cold pressing technique was addressed. Mixtures of Cu-20vol%NbC powder were prepared by two methods.
In first method, a mixture of Cu-15.79wt%Nb-2.04wt%C powder was milled at 400 rpm for 35 hours in a planetary mill. In second method, Cu and commercial NbC powder was mixed at 100 rpm for 2 hours in a jar mill. Then, both powders were pressed at different pressure (i.e. 350 MPa, 450 MPa, 550 MPa and 650 MPa) and sintered at 900 o C for 1 hour. Sample of in-situ and ex-situ Cu-20vol%NbC composite were characterized for density, hardness, phase formation by x-ray diffraction analysis and microstructure by scanning electron microscope. Xray diffraction analysis showed that NbC phase was formed in the in-situ processed sample. Hardness of in-situ processed copper composite was higher than that of the ex-situ processed copper composite due to good interface between coper matrix and niobium carbide reinforcement particle as well as distribution of finer niobium carbide particles in copper matrix. Sintered density of in-situ composite is lower than density of ex-situ composite beacuse of work hardening of the Cu-Nb-C mixture powder during powder to ball collision. Density and hardness of the in-situ and ex-situ Cu-20vol%NbC composites increase with the increase in compaction pressure as porosity is eliminated at higher compaction pressure.
Silicon nanostructures have successfully been synthesized by thermal evaporation technique using nickel catalyst. Silicon powder served as starting source material was evaporated at high temperature (900-1100°C) in inert carrier gas. The grown silicon nanostructures were collected on (111) silicon substrate surface that positioned at varied location from source material. By controlling heating rate, gas flow rate, growth temperature and time, substrate position and location; to the optimum condition produced the best quality at silicon nanostructures. In this work, the best parameter to produce silicon nanostructures is system ramping up 1000°C at 20°C/min heating rate, N2 flow at 100ml/min; silicon needle-like one dimensional silicon nanostructures growth on vertically-positioned substrate located at 12cm from source material for 1 hour growth time. The effects of these parameters on the structures and physical of nanostructures were characterized by field emission scanning electron microscope and x-ray diffraction.
Materials that can enhance the sensitivity and selectivity of a biosensor are greatly in demand. The nanocomposition of thionine (Th) and graphene can increase the electroconductivity of the working electrode used. Graphene is a very good electrical conductor but is also hydrophobic in nature. Composition with thionine gives it the capability to disperse well in water. Plus, thionine provides the opportunity for DNA probes to be immobilized due to the presence of the amino group in its structure. In this research, the thionine-graphene (Th-G) nanocomposite was synthesized through filtration and characterised using scanning electron microscopy (SEM) to distinguish different elements coexist in the nanocomposite and to investigate the microstructure changes of the nanocomposite to confirm the composition. Different elements were analyzed to test the presence of both thionine and graphene in the composition. Physical characterisation through SEM proved the nanocomposition was a success.
Transition metals play an important role in the growth of carbon nanotubes (CNTs). Series of unsupported hybrid catalysts consisting of Ni:Cu, Ni:Cr, and Ni:Mn doped with Nd catalyst, respectively were synthesized by impregnation method. The catalytic performance of the catalyst for the production of CNTs was measured in the pyrolysis process of hydrocarbon source by catalytic chemical vapour deposition method. Acetylene gas was used as the source of carbon in the pyrolysis process. The decomposition of acetylene was carried out at 700ºC. The bulk properties of the catalysts were investigated by X-ray diffraction. Field emission scanning electron microscopy and thermal analysis were used to observe the morphology and thermal stability of the as-synthesized CNTs, respectively. Hybrid catalyst of Ni:Mn/Nd and Ni:Cr/Nd in 3:1 atomic ratio gave high percentage of carbon yield which was assigned for the high production of CNTs with the mass of yield 18 times greater than the initial mass of the catalyst used.
A study on the effect of the modify values of x in CaCu3-xMn4+xO12 system has been carried out with x = 0.1, 0.3, 0.5, 0.7 and 0.9. The materials were prepared via solid-state reaction. The preparation conditions have been optimized using thermogravimetry analysis (TGA) technique. Material formations under the reported conditions have been confirmed by X-ray diffraction (XRD) studies. The results show that the formation of CaCu3Mn4O12 started at calcinations temperature of 600 0 C with the presence of raw material and was formed completely at 850 0 C. Field emission scanning electron microscopy (FESEM) analysis indicated that the increase of x value in the composition had changed the microstructures to be more faceted. The impedance spectrum is characterized by the appearance of two semicircle arcs whose pattern of evolution changes with rise of values x in the CaCu3-xMn4+xMn4O12 system. Bulk resistance (Rb) and grain boundary resistance (Rgb) of CaCu3- xMn4+xO12 decreases form 824.24 : to 98.68 : and 418.18 : to 2.20 : respectively, with the increasing of x value.
The amount of sugarcane bagasse and rice straw in the state of Perlis (Malaysia) is abundant while its utilization is still limited. One of the alternatives for the bagasse and straw utilization is as pulp raw material. This paper reviews on pulp from sugarcane bagasse and rice straw and its suitability for paper production. In this study, the pulp was extracted by the Soxhlet extraction method. The objective of this study was to investigate the cellulose, lignin and silica content of the pulp from sugarcane bagasse and rice straw. For rice straw, the presence of large amount of pentosanes in the pulp and black liquors, which also contain silica were decreased the using of straw in the paper industry. Therefore, formic acid pulping and NaOH treatment are studied to reduce or prevent silica. The isolated pulp samples were further characterized by Scanning Electron Microscope (SEM) to investigate their fiber dimensions.
This study demonstrated the utilization of radiation-induced initiator methods for the formation of
nanoparticles of Acrylated Palm Oil (APO) using aqueous Pluronic F-127 (PF-127) microemulsion
system. This microemulsion system was subjected to gamma irradiation to form the crosslinked APO
nanoparticles. Dynamic light scattering (DLS), Fourier Transform Infrared (FTIR) spectroscopy and
Transmission Electron Microscopy (TEM) were used to characterize the size and the chemical structure
of the nanoparticles. As a result, the size of the APO nanoparticle was decreased when the irradiation
dose increased. The decrease in size might be due to the effects of intermolecular crosslinking and
intramolecular crosslinking reactions of the APO nanoparticles during irradiation process. The size of the
nanoparticle is in the range of 98 to 200 nanometer (nm) after irradiation using gamma irradiator. This radiation-induced method provides a free initiator
induced and easy to control process as compared
to the classical or chemical initiator process. The
study has shown that radiation-induced initiator
methods, namely, polymerization and crosslinking
in the microemulsion, were promising for the
synthesis of nanoparticles.
Detection and analysis of resin is particularly significant since the commercial value of agarwood is related to the quantity of resins that are present. This article explores the potential of a scanning electron microscope in combination with new non-destructive 3D visualization technique, X-ray micro-computed tomography, as imaging tools to visualize micro-structure resin in agarwood. These techniques were used to compare two samples of agarwood chips: high grade and low grade. From the results, it can be concluded that a wood cell filled with resin deposit have a higher attenuation. It can be shown that the combination of scanning electron microscopy and micro-CT can offer high resolution images concerning the localization and structure of resin inside Agarwood. While the second allows the 3D investigation of internal structure of agarwood, the first technique can provide details 2D morphological information. These imaging techniques, although sophisticated can be used for standard development especially in grading of agarwoodlbr commercial activities.
Kenaf fibre that is known as Hibiscus cannabinus, L. family Malvaceae is an herbaceous plant that can be grown under a wide range of weather conditions. The uses of kenaf fibres as a reinforcement material in the polymeric matrix have been widely investigated. It is known that epoxy has a disadvantage of brittleness and exhibits low toughness. In this research, liquid epoxidized natural rubber (LENR) was introduced to the epoxy to increase its toughness. Kenaf fibres, with five different fibre loadings of 5%, 10%, 15%, 20% and 25% by weight, were used to reinforce the epoxy resins (with and without addition of epoxidized natural rubber) as the matrices. The flexural strength, flexural modulus and fracture toughness of the rubber toughened epoxy reinforced kenaf fibre composites were investigated. The results showed that the addition of liquid epoxidized natural rubber (LENR) had improved the flexural modulus, flexural strength and fracture toughness by 48%, 30%, and 1.15% respectively at 20% fibre loading. The fractured surfaces of these composites were investigated by using scanning electron microscopic (SEM) technique to determine the interfacial bonding between the matrix and the fibre reinforcement.
Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.
Preparations of influenza virus A0 PR8/34 and A2 Malaysia/68 have been studied in the electron microscope. They were similar in appearance to preparations made by others. Each preparation was degraded by Triton N 101. The process of degradation appeared to be different from that observed using ether and, by inference, a number of other agents.
Heat treatment was introduced onto the aluminum coated low carbon steel to promote the formation of thin layer of oxide for enhancement of oxidation protection of steel. This process has transformed the existing intermetallic layer formed during hot dip aluminizing process. Experiment was conducted on the low carbon steel substrates with 10mm x 10mm x 2mm dimension. Hot dip aluminizing of low carbon steel was carried out at 750 ºC dipping temperature in a molten pure aluminum for 5 minutes. Aluminized samples were heat treated at 600 ºC, 700 ºC, 800 ºC, and 900 ºC for 1 hour. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and EDAX were used in investigation. From the observation, it showed the intermetallic thickness increased with the increase in temperature. The result of EDAX analysis revealed the existence of oxide phase and the intermetallics. The XRD identified the intermetallics as Fe2Al5 and FeAl3.
With a view to understanding the effect of rare earth element (Ce, Pr, Nd, Sm and Gd) substitution for the La site in LaMnO3 (LMO), the samples were prepared via solid-state reaction. Structure investigation by X-ray diffraction (XRD) showed that structure transformation from trigonal (LMO) to orthorhombic (PMO, NMO, SMO and GMO) occurred when smaller trivalent rare earth element was replaced. The MnO6 octahedra were tilted and elongated or compressed, corresponding to the ionic radii of the rare earth inserted. Meanwhile, microstructure study using scanning electron microscopy (SEM) illustrated that La substitution by another rare earth element caused a reduction in grain size. This might due to the changes in enthalpy of fusion by other rare earth ions, where higher enthalpy of fusion favours formation of smaller grain size. However, CeMnO3 did not form under this preparation condition. The magnetic properties studied from the hysteresis plot taken at room temperature indicated that the substitution of La with other magnetic trivalent rare earth ions strongly weakened the magnetic strength of the system.
This study was conducted to prepare a mixed matrix membrane (MMM) and to test the performance of the prepared MMM for CO2 and CH4 gas separation. MMM containing polyethersulfone (PES) and multi-walled carbon nanotubes (MWCNTs) was prepared by a dry-wet phase inversion technique using a pneumatically-controlled membrane casting machine. The surface modification was performed on MWCNTs in order to enhance the selectivity of CO2/CH4. The surface modification of MWCNTs using chemical and physical approaches has been adopted. Mixed acid (HNO3/H2SO4) and β-CD were used for chemical and physical approaches, respectively. Effects of surface modification on MWCNTs/PES MMM were investigated. MWCNTs/PES MMMs were characterised using scanning electron microscopy (SEM), the Fourier Transform Infrared (FT-IR) spectroscopy and pure gas permeation test. The permeability and selectivity, which are the parameters describing membrane performance were calculated via the data obtained from pure gas permeation test with the feed pressure difference from 3 to 7 bars. In this study, surface modified MWCNTs/PES MMM using mixed acid and β-CD has successfully enhanced the CO2/CH4 selectivity by 40.6% compared to that of neat PES.
A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.
Monoclinic bismuth oxide (α-Bi2O3) nanoparticles were prepared via precipitation method and
irradiated with a pulsed laser forming thin films. Their phase and surface morphological properties
were investigated using x-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron
microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). The XRD
analysis shows the phase transformation to a partially crystalline tetragonal phase β-Bi2O3 thin film.
The SEM micrograph of the nanoparticles, with an average crystal size of 72 nm, was seen to form
a thin film with a peculiar structure, coined as “cotton-like”, is attributed to the high surface energy
absorbed by the nanoparticles during ablation. The HR-TEM micrograph shows the particulate with
a clearly defined interlayer spacing.
Titanium alloy (e.g. Ti-6Al-4V) has an excellent combination of properties. However in many cases,
the application is limited because of the poor wear property. In this work, a surface modification
(plasma nitriding) is carried out to improve the surface properties of Ti-6Al-4V, as a treatment prior to a hardcoating deposition, leading to a duplex coating system. This is an effort to improve the surface and near surface property of Ti-6Al-4V. Plasma nitriding is performed utilizing microwave plasma method in 25% Ar- 75% N2 atmosphere at temperatures of 600°C and 700°C for different processing times (1, 3 and 5 hours). The phase and microstructure of plasma nitrided substrate were characterized by using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The plasma nitrided Ti-6Al-4V properties (surface roughness, surface hardness and case depth) were determined using profilometer and microhardness, respectively. Results obtained showed a significant increase on the surface hardness of Ti-6Al-4V. This is due to the formation of TiN and Ti2N phases in the form of compound layer. Besides, it shows that the diffusion of nitrogen into the Ti-6Al-4V substrate produces case depth up to 130 µm and this contributes to the improvement of the near surface hardness due to the changes in the microstructures. It was also found that the surface hardness and surface roughness increased with the increases in the process temperature and times.