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Fulltext Application of Environmental Scanning Electron Microscope-Nanomanipulation System on Spheroplast Yeast Cells Surface Observation

Rad MA, Ahmad MR, Nakajima M, Kojima S, Homma M, Fukuda T

Scanning, 2017;2017:8393578.
PMID: 29109826 DOI: 10.1155/2017/8393578

The preparation and observations of spheroplast W303 cells are described with Environmental Scanning Electron Microscope (ESEM). The spheroplasting conversion was successfully confirmed qualitatively, by the evaluation of the morphological change between the normal W303 cells and the spheroplast W303 cells, and quantitatively, by determining the spheroplast conversion percentage based on the OD800 absorbance data. From the optical microscope observations as expected, the normal cells had an oval shape whereas spheroplast cells resemble a spherical shape. This was also confirmed under four different mediums, that is, yeast peptone-dextrose (YPD), sterile water, sorbitol-EDTA-sodium citrate buffer (SCE), and sorbitol-Tris-Hcl-CaCl2 (CaS). It was also observed that the SCE and CaS mediums had a higher number of spheroplast cells as compared to the YPD and sterile water mediums. The OD800 absorbance data also showed that the whole W303 cells were fully converted to the spheroplast cells after about 15 minutes. The observations of the normal and the spheroplast W303 cells were then performed under an environmental scanning electron microscope (ESEM). The normal cells showed a smooth cell surface whereas the spheroplast cells had a bleb-like surface after the loss of its integrity when removing the cell wall.

Matched MeSH terms: Microscopy, Electron, Scanning*
Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Ong WJ, Tan LL, Ng YH, Yong ST, Chai SP

Chem Rev, 2016 06 22;116(12):7159-329.
PMID: 27199146 DOI: 10.1021/acs.chemrev.6b00075

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and "earth-abundant" nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The construction and characteristics of each classification of the heterojunction system will be critically reviewed, namely metal-g-C3N4, semiconductor-g-C3N4, isotype g-C3N4/g-C3N4, graphitic carbon-g-C3N4, conducting polymer-g-C3N4, sensitizer-g-C3N4, and multicomponent heterojunctions. The band structures, electronic properties, optical absorption, and interfacial charge transfer of g-C3N4-based heterostructured nanohybrids will also be theoretically discussed based on the first-principles density functional theory (DFT) calculations to provide insightful outlooks on the charge carrier dynamics. Apart from that, the advancement of the versatile photoredox applications toward artificial photosynthesis (water splitting and photofixation of CO2), environmental decontamination, and bacteria disinfection will be presented in detail. Last but not least, this comprehensive review will conclude with a summary and some invigorating perspectives on the challenges and future directions at the forefront of this research platform. It is anticipated that this review can stimulate a new research doorway to facilitate the next generation of g-C3N4-based photocatalysts with ameliorated performances by harnessing the outstanding structural, electronic, and optical properties for the development of a sustainable future without environmental detriment.

Matched MeSH terms: Microscopy, Electron/methods
Egg structure and outline of embryonic development of the basal mantodean, Metallyticus splendidus Westwood, 1835 (Insecta, Mantodea, Metallyticidae)

Fukui M, Fujita M, Tomizuka S, Mashimo Y, Shimizu S, Lee CY, et al.

Arthropod Struct Dev, 2018 Jan;47(1):64-73.
PMID: 29109050 DOI: 10.1016/j.asd.2017.11.001

The egg structure and outline of the embryonic development of Metallyticus splendidus of one of the basal Mantodea representatives, Metallyticidae, were described in the present study. The results obtained were compared with those from the previous studies, to reconstruct and discuss the groundplan of Mantodea and Dictyoptera. In M. splendidus, the egg is spheroidal, it has a convex ventral side at the center in which numerous micropyles are grouped, and it possesses a conspicuous hatching line in its anterior half. These are the groundplan features of mantodean eggs and the "grouped micropyles in the ventral side of the egg" are regarded as an apomorphic groundplan feature of Dictyoptera. A small circular embryo is formed by a simple concentration of blastoderm cells, which then undergoes embryogenesis of the typical short germ band type. Blastokinesis is of the "non-reversion type" and the embryo keeps its original superficial position and original orientation throughout embryonic development. During the middle stages of development, the embryo undergoes rotation around the egg's anteroposterior axis. These features are a part of the groundplan of Mantodea. It is uncertain whether sharing of the "non-reversion type" of blastokinesis by Mantodea and blaberoidean Blattodea can be regarded as homology or homoplasy.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Fulltext Optimization of the Synthesis of Superhydrophobic Carbon Nanomaterials by Chemical Vapor Deposition

Aljumaily MM, Alsaadi MA, Das R, Hamid SBA, Hashim NA, AlOmar MK, et al.

Sci Rep, 2018 02 09;8(1):2778.
PMID: 29426860 DOI: 10.1038/s41598-018-21051-3

Demand is increasing for superhydrophobic materials in many applications, such as membrane distillation, separation and special coating technologies. In this study, we report a chemical vapor deposition (CVD) process to fabricate superhydrophobic carbon nanomaterials (CNM) on nickel (Ni)-doped powder activated carbon (PAC). The reaction temperature, reaction time and H2/C2H2 gas ratio were optimized to achieve the optimum contact angle (CA) and carbon yield (CY). For the highest CY (380%) and CA (177°), the optimal reaction temperatures were 702 °C and 687 °C, respectively. However, both the reaction time (40 min) and gas ratio (1.0) were found to have similar effects on CY and CA. Based on the Field emission scanning electron microscopy and transmission electron microscopy images, the CNM could be categorized into two main groups: a) carbon spheres (CS) free carbon nanofibers (CNFs) and b) CS mixed with CNFs, which were formed at 650 and 750 °C, respectively. Raman spectroscopy and thermogravimetric analysis also support this finding. The hydrophobicity of the CNM, expressed by the CA, follows the trend of CS-mixed CNFs (CA: 177°) > CS-free CNFs (CA: 167°) > PAC/Ni (CA: 65°). This paves the way for future applications of synthesized CNM to fabricate water-repellent industrial-grade technologies.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Fulltext Biomolecular characterization of diazotrophs isolated from the tropical soil in Malaysia

Naher UA, Othman R, Latif MA, Panhwar QA, Amaddin PA, Shamsuddin ZH

Int J Mol Sci, 2013 Aug 30;14(9):17812-29.
PMID: 23999588 DOI: 10.3390/ijms140917812

This study was conducted to evaluate selected biomolecular characteristics of rice root-associated diazotrophs isolated from the Tanjong Karang rice irrigation project area of Malaysia. Soil and rice plant samples were collected from seven soil series belonging to order Inceptisol (USDA soil taxonomy). A total of 38 diazotrophs were isolated using a nitrogen-free medium. The biochemical properties of the isolated bacteria, such as nitrogenase activity, indoleacetic acid (IAA) production and sugar utilization, were measured. According to a cluster analysis of Jaccard's similarity coefficients, the genetic similarities among the isolated diazotrophs ranged from 10% to 100%. A dendogram constructed using the unweighted pair-group method with arithmetic mean (UPGMA) showed that the isolated diazotrophs clustered into 12 groups. The genomic DNA rep-PCR data were subjected to a principal component analysis, and the first four principal components (PC) accounted for 52.46% of the total variation among the 38 diazotrophs. The 10 diazotrophs that tested highly positive in the acetylene reduction assay (ARA) were identified as Bacillus spp. (9 diazotrophs) and Burkholderia sp. (Sb16) using the partial 16S rRNA gene sequence analysis. In the analysis of the biochemical characteristics, three principal components were accounted for approximately 85% of the total variation among the identified diazotrophs. The examination of root colonization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) proved that two of the isolated diazotrophs (Sb16 and Sb26) were able to colonize the surface and interior of rice roots and fixed 22%-24% of the total tissue nitrogen from the atmosphere. In general, the tropical soils (Inceptisols) of the Tanjong Karang rice irrigation project area in Malaysia harbor a diverse group of diazotrophs that exhibit a large variation of biomolecular characteristics.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Fulltext Fabrication of Nanocollagen Using Enhanced Cryogenic Milling Method with Graphene Oxide

Lo S, Mahmoudi E, Qi Hao L, Mohd Nor F, Fauzi MB

Int J Nanomedicine, 2024;19:6845-6855.
PMID: 39005957 DOI: 10.2147/IJN.S465189

OBJECTIVE: Collagen, a widely used natural biomaterial polymer in skin tissue engineering, can be innovatively processed into nanocollagen through cryogenic milling to potentially enhance skin tissue healing. Although various methods for fabricating nanocollagen have been documented, there is no existing study on the fabrication of nanocollagen via cryogenic milling, specifically employing graphene oxide as separators to prevent agglomeration.
METHODS: In this study, three research groups were created using cryogenic milling: pure nanocollagen (Pure NC), nanocollagen with 0.005% graphene oxide (NC + 0.005% GO), and nanocollagen with 0.01% graphene oxide (NC+0.01% GO). Characterization analyses included transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), zeta potential (ZP), and polydispersity index (PDI).
RESULTS: TEM and SEM analysis revealed that nanocollagen groups alone exhibited particle sizes of less than 100 nm. FTIR spectroscopic investigations indicated the presence of amide A, B, and I, II, and III (1800 to 800 cm-1) in all nanocollagen study groups, with the characteristic C-O-C stretching suggesting the incorporation of graphene oxide (GO). XRD data exhibited broadening of the major peak as the proportion of GO increased from pure NC to the nanocollagen groups with GO. Zeta potential measurements indicated electrostatic attraction of the samples to negatively charged surfaces, accompanied by sample instability. PDI results depicted size diameters ranging from 800 to 1800 nm, indicating strong polydispersity with multiple size populations.
CONCLUSION: This research demonstrated that collagen can be successfully fabricated into nanoparticles with sizes smaller than 100 nm.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Fulltext Enhancement of the wear resistance and microhardness of aluminum alloy by Nd:YaG laser treatment

Hussein HT, Kadhim A, Al-Amiery AA, Kadhum AA, Mohamad AB

ScientificWorldJournal, 2014;2014:842062.
PMID: 25136694 DOI: 10.1155/2014/842062

Influence of laser treatment on mechanical properties, wear resistance, and Vickers hardness of aluminum alloy was studied. The specimens were treated by using Nd:YaG laser of energy 780 mj, wavelength 512 nm, and duration time 8 ns. The wear behavior of the specimens was studied for all specimens before and after treatment by Nd:YaG laser and the dry wear experiments were carried out by sing pinon-disc technique. The specimens were machined as a disk with diameter of 25 mm and circular groove in depth of 3 mm. All specimens were conducted by scanning electron microscopy (SEM), energy-dispersive X-ray fluorescence analysis (EDS), optical microscopy, and Vickers hardness. The results showed that the dry wear rate was decreased after laser hardening and increased Vickers hardness values by ratio of 2.4:1. The results showed that the values of wear rate for samples having circular grooves are less than samples without grooves after laser treatment.

Matched MeSH terms: Microscopy, Electron, Scanning
Biological treatment of produced water in a sequencing batch reactor by a consortium of isolated halophilic microorganisms

Pendashteh AR, Fakhru'l-Razi A, Chuah TG, Radiah AB, Madaeni SS, Zurina ZA

Environ Technol, 2010 Oct;31(11):1229-39.
PMID: 21046953 DOI: 10.1080/09593331003646612

Produced water or oilfield wastewater is the largest volume ofa waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m(-3) d(-1), 1.8 kg COD m(-3) d(-1) and 3.6 kg COD m(-3) d(-1)) and different total dissolved solids (TDS) concentration (35,000 mg L(-1), 100,000 mg L(-1), 150,000 mg L(-1), 200,000 mg L(-1) and 250,000 mg L(-1)). It was found that with an OLR of 0.9 kg COD m(-3) d(-1) and 1.8 kg COD m(-3) d(-1), average oil and grease (O&G) concentrations in the effluent were 7 mg L(-1) and 12 mg L(-1), respectively. At TDS concentration of 35,000 mg L(-1) and at an OLR of 1.8 kg COD m(-3)d(-1), COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L(-1), COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83%, and 85%, respectively.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Megakaryoblastic transformation of chronic granulocytic leukaemia: a case report

Yong KL, Chan KW

Med J Malaysia, 1982 Sep;37(3):231-4.
PMID: 6960229

A 38 year old patient unth. chronic granulocytes leukaemia, subsequently presented untli blast transformation. nineteen. months later. Conventional light microscopy and cytochemistry were not helpful in elucidating the type of blast cell. Electron microscopy however identifies the blasts to be of megakaryocytic series.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Enhanced flexibility of polylactic acid/epoxidized palm oil/pineapple fiber composites

Nur Lisa Farhana Mohamad, Fathilah Binti Ali, Azlin Suhaida Azmi, Barre, Mohamed Soleiman, Hazleen Anuar

Biological and Natural Resources Engineering Journal, 2020;3(1):1-7.
MyJurnal

The concern about our dependency on non-renewable resources and overwhelming environmental issues such as pollution caused by non-degradable packaging materials has prompted researchers to come up with alternatives to solve this problem. Thermoplastic polylactic acid (PLA) has been gaining interest due to its versatility and easy processability, thus this study was carried out to find out the properties of PLA reinforced with pineapple fibers. However, surface of the natural fibers need to be treated for better properties enhancement in the polymer matrices. Considering this, fibers were treated with 10% (w/v) concentration of potassium hydroxide (KOH) and then continued for mixing with PLA at a fixed ratio of plasticizer by using internal mixer, and then the composites were prepared into sheet via hot press. Characterization for the mechanical and morphological was conducted by using tensile testing and scanning electron microscopy, respectively. After the analysis, it is found that the surface treated pineapple fiber composite showed better elongation at break compared to untreated fiber composite. The enhance properties of PLA nanocomposites has potential to be used in various packaging materials.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Enhancement of Particle Alignment Using Silicone Oil Plasticizer and Its Effects on the Field-Dependent Properties of Magnetorheological Elastomers

Khairi MHA, Fatah AYA, Mazlan SA, Ubaidillah U, Nordin NA, Ismail NIN, et al.

Int J Mol Sci, 2019 Aug 21;20(17).
PMID: 31438576 DOI: 10.3390/ijms20174085

The existing mold concept of fabricating magnetorheological elastomer (MRE) tends to encounter several flux issues due to magnetic flux losses inside the chamber. Therefore, this paper presents a new approach for enhancing particle alignment through MRE fabrication as a means to provide better rheological properties. A closed-loop mold, which is essentially a fully guided magnetic field inside the chamber, was designed in order to strengthen the magnetic flux during the curing process with the help of silicone oil (SO) plasticizers. The oil serves the purpose of softening the matrix. Scanning electron microscopy (SEM) was used to observe the surface morphology of the fabricated MRE samples. The field-dependent dynamic properties of the MREs were measured several ways using a rheometer, namely, strain sweep, frequency sweep, and magnetic field sweep. The analysis implied that the effectiveness of the MRE was associated with the use of the SO, and the closed-loop mold helped enhance the absolute modulus up to 0.8 MPa. The relative magnetorheological (MR) effects exhibited high values up to 646%. The high modulus properties offered by the MRE with SO are believed to be potentially useful in industry applications, particularly as vibration absorbers, which require a high range of stiffness.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Evaluation of Interfacial Fracture Toughness and Interfacial Shear Strength of Typha Spp. Fiber/Polymer Composite by Double Shear Test Method

Ikramullah, Rizal S, Nakai Y, Shiozawa D, Khalil HPSA, Huzni S, et al.

Materials (Basel), 2019 Jul 10;12(14).
PMID: 31295885 DOI: 10.3390/ma12142225

The aim of this paper is to evaluate the Mode II interfacial fracture toughness and interfacial shear strength of Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite by using a double shear stress method with 3 fibers model composite. The surface condition of the fiber and crack propagation at the interface between the fiber and the matrix are observed by scanning electron microscope (SEM). Alkali treatment on Typha spp. fiber can make the fiber surface coarser, thus increasing the value of interfacial fracture toughness and interfacial shear strength. Typha spp. fiber/epoxy has a higher interfacial fracture value than that of Typha spp. fiber/PLLA. Interfacial fracture toughness on Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite model specimens were influenced by the matrix length, fiber spacing, fiber diameter and bonding area. Furthermore, the interfacial fracture toughness and the interfacial fracture shear stress of the composite model increased with the increasing duration of the surface treatment.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties

Soomro IA, Pedapati SR, Awang M

Materials (Basel), 2021 Feb 08;14(4).
PMID: 33567606 DOI: 10.3390/ma14040802

Resistance spot welding (RSW) of dual phase (DP) steels is a challenging task due to formation of brittle martensitic structure in the fusion zone (FZ), resulting in a low energy capacity of the joint during high-rate loading. In the present study, in situ postweld heat treatment (PWHT) was carried out by employing a double pulse welding scheme with the aim of improving the mechanical performance of DP590 steel resistance spot weld joint. Taguchi method was used to optimize in situ PWHT parameters to obtain maximum peak load and failure energy. Experiments were designed based on orthogonal array (OA) L16. Mechanical performance was evaluated in terms of peak load and failure energy after performing low dynamic tensile shear (TS) test. Microstructural characterization was carried out using a scanning electron microscope (SEM). The results show that improvements of 17 and 86% in peak load and failure energy, respectively, were achieved in double-pulse welding (DPW) at optimum conditions compared to traditional single-pulse welding (SPW). The improvement in mechanical performance resulted from (i) enlargement of the FZ and (ii) improved weld toughness due to tempering of martensite in the FZ and subcritical heat affected zone (SCHAZ). These factors are influenced by heat input, which in turn depends upon in situ PWHT parameters.

Matched MeSH terms: Microscopy, Electron, Scanning
Complex permittivity and power loss characteristics of α-Fe2O3/polycaprolactone (PCL) nanocomposites: effect of recycled α-Fe2O3 nanofiller

Mensah EE, Abbas Z, Azis RS, Ibrahim NA, Khamis AM, Abdalhadi DM

Heliyon, 2020 Dec;6(12):e05595.
PMID: 33305050 DOI: 10.1016/j.heliyon.2020.e05595

The development of microwave absorbing materials based on recycled hematite (α-Fe2O3) nanoparticles and polycaprolactone (PCL) was the main focus of this study. α-Fe2O3 was recycled from mill scale and reduced to nanoparticles through high energy ball milling in order to improve its complex permittivity properties. Different compositions (5% wt., 10% wt., 15% wt. and 20% wt.) of the recycled α-Fe2O3 nanoparticles were melt-blended with PCL using a twin screw extruder to fabricate recycled α-Fe2O3/PCL nanocomposites. The samples were characterized for their microstructural properties through X - ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The complex permittivity and microwave absorption properties were respectively measured using the open ended coaxial (OEC) probe and a microstrip in connection with a vector network analyzer in the 1-4 GHz frequency range. An average α-Fe2O3 nanoparticle size of 16.2 nm was obtained with a maximum imaginary (ε") part of permittivity value of 0.54 at 4 GHz. The complex permittivity and power loss values of the nanocomposites increased with recycled α-Fe2O3 nanofiller content. At 2.4 GHz, the power loss (dB) values obtained for all the nanocomposites were between 13.3 dB and 14.4 dB and at 3.4 GHz, a maximum value of 16.37 dB was achieved for the 20 % wt. nanocomposite. The recycled α-Fe2O3/PCL nanocomposites have the potential for use in noise reduction applications in the 1-4 GHz range.

Matched MeSH terms: Microscopy, Electron, Transmission
Cutting efficiency of different dental materials utilized in an air abrasion system

Hassan U, Farooq I, Moheet IA, AlShwaimi E

Int J Health Sci (Qassim), 2017 Sep-Oct;11(4):23-27.
PMID: 29085264

OBJECTIVES: The aim of the present study was to test cutting efficiency of different materials against conventional alumina in an air abrasion system.

MATERIALS AND METHODS: The powder samples were divided into three groups: Group 1 - alumina (control), Group 2 - 45S5 bioactive glass, and Group 3 - hydroxyapatite. 30 microscope glass slides of 0.5 mm thickness were used as an alternative of human enamel and were also divided randomly into these three groups. The time taken by the abrasive particles to cut a hole through the microscope glass slide was recorded with a stop watch. In addition, morphology of the particles was observed through scanning electron microscopy (SEM). A t-test was used to compare the times taken to cut a hole through the microscope glass slides, and the level of significance was set at P < 0.05.

RESULTS: The mean time taken to cut a hole through the microscope glass slide was 2.96 s and 23.01s for Groups 1 and 2, respectively, whereas powder of Group 3 did not cut after 120 s. The differences between cutting times of Groups 1 and 2 were statistically significant (P < 0.05). The SEM micrographs revealed coarse angular shape for particles of Groups 1 and 2 but Group 3 particles were with round ends and presence of smaller particles was also observed in Groups 2 and 3.

CONCLUSION: The alumina particles demonstrated excellent cutting efficiency followed by 45S5 particles. The use of bioactive glass particles should be encouraged for cutting purposes whenever a shortage of time for practitioners is not a concern.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Microstructural evolution and growth kinetics of Sn-40Pb/Cu solder joint during long-term aging at 125°C

Mayappan, Ramani, Ahmad Badri Ismail, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2009;2009(1):165-172.
MyJurnal

The microstructural evolution of Sn-40Pb/Cu joints has been investigated under 125 o C thermal exposure conditions using single shear lap joints. A scanning electron microscope (SEM) was used to observe the morphology of the phases and energy dispersive x-ray (EDX) was used to estimate the elemental compositions of the phases. A double layer of Cu6Sn5 and Cu3Sn were observed. The Cu6Sn5 developed with a scalloped morphology, while the Cu3Sn always grew as a somewhat undulated planar layer in phase with the Cu6Sn5. The Cu6Sn5 layer began to transform from scallop shape to planar type after aging for 375 hours due to reduction in the interfacial energy. The intermetallic layers showed a linear dependence on the square root of aging time. The growth rate constant of the intermetallic compounds are estimated as 15.2 x 10 - 14 and 0.152 x 10 -14 cm 2 /s for Cu6Sn5 and Cu3Sn intermetallic, respectively.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Effects of γ-rays on electrical conductivity of polyvinyl alcohol-polypyrrole composite polymer films

Mohd Hamzah Harun, Elias Saion, Noorhana Yahya, Anuar Kassim, Hussain, Muhammad Yousuf, Iskandar Shahrim Mustafa, et al.

Journal of Nuclear and Related Technologies, 2007;2007(1):1-12.
MyJurnal

The composite polymer films of polyvinyl alcohol/polypyrrole/chloral hydrate (PVA-PPy-CH) had been prepared. Effects of γ-rays on the electrical conductivity of the composite polymer films had been investigated by using Inductance Capacitance Resistance meter (LCR) meter at a frequency ranging from 20 Hz to 1 MHz. With the incorporation of chloral hydrate in the polymer sample, the conductivity increased indicates that it is capable to be used as dopant for polymerizing conjugated polymer. The electrical conductivity obtained increased as the dose increased, which is in the order of 10-5 Scm-1 indicates that γ-rays is capable to enhance the electrical conductivity of the composite polymer films. The parameter of s is in the range of 0.31 d s d 0.49 and obeyed simple power law dispersion ωs. The Scanning Electron Microscopy (SEM) micrographs reveal the formation of polypyrrole globules in polyvinyl alcohol matrix which increased as the irradiation dose was increased.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Effect of slurries density on the properties of ceramic foam produced via polymer replication method

Mohd Al Amin Muhamad Nor, Lee, Chain Hong, Hazizan Md. Akil, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2007;2005(1):35-41.
MyJurnal

Ceramic foams are a class of high porosity materials that are used or being considered for a wide range of technological applications. Ceramic foam was produce by polymer replication method. In this process, commercial polymeric sponge was use as template, dipping with ceramic particles slurry, drying and then sintered to yield a replica of the original foams. The study was focus on the fabrication of different density of ceramic foams by varying the density of ceramic slurries (1.1876, 1.2687, 1.3653 and 1.5295 g/cm3). Properties of ceramic foam produced such as density was characterized accordingly to ASTM C 271-94 and porosity were characterized using Archimedes methods. Compressive and bending strength was performed accordingly to ASTM C1161-94 and C773-88 (1999), respectively. The morphological study was performed using Scanning Electron Microscopy (SEM) and EDX. Density of ceramic foams produced was about 0.5588 and 1.1852 g/cm3, where as porosity was around 26.28 and 70.59 %. Compressive and bending strength was increase from strength also increases from 2.60 to 23.07 MPa and 1.20 to 11.10 MPa, respectively, with increasing of slurries density from 1.1876 to 1.3653 g/cm3. The SEM micrographs show that the cells structure become denser as the slurries density increased. EDX proved that the ceramic used is porcelain. As a conclusion, increasing in slurries density produced ceramic foams with good mechanical properties such as compressive and bending strength and denser body.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Characterization of alumina using small angle neutron scattering (sans)

Megat Harun Al Rashid Megat Ahmad, Abdul Aziz Mohamed, Azmi Ibrahim, Che Seman Mahmood, Putra, Edy Giri Rachman, Muhammad Rawi Muhammad Zin, et al.

Journal of Nuclear and Related Technologies, 2007;2005(1):19-23.
MyJurnal

Alumina powder was synthesized from an aluminum precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was of high purity and highly crystalline D-phase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder.

Matched MeSH terms: Microscopy, Electron, Transmission
Fulltext Enhanced Capacitance of Hybrid Layered Graphene/Nickel Nanocomposite for Supercapacitors

Mohd Zaid NA, Idris NH

Sci Rep, 2016 08 24;6:32082.
PMID: 27553290 DOI: 10.1038/srep32082

In this work, Ni nanoparticles were directly decorated on graphene (G) nanosheets via mechanical ball milling. Based on transmission electron microscopy observations, the Ni nanoparticles were well dispersed and attached to the G nanosheet without any agglomerations. Electrochemical results showed that the capacitance of a G/Ni nanocomposite was 275 F g(-1) at a current density of 2 A g(-1), which is higher than the capacitance of bare G (145 F g(-1)) and bare Ni (3 F g(-1)). The G/Ni electrode also showed superior performance at a high current density, exhibiting a capacitance of 190 F g(-1) at a current density of 5 A g(-1) and a capacitance of 144 F g(-1) at a current density of 10 A g(-1). The equivalent series resistance for G/Ni nanocomposites also decreased. The enhanced performance of this hybrid supercapacitor is best described by the synergistic effect, i.e. dual charge-storage mechanism, which is demonstrated by electrical double layer and pseudocapacitance materials. Moreover, a high specific surface area and electrical conductivity of the materials enhanced the capacitance. These results indicate that the G/Ni nanocomposite is a potential supercapacitor.

Matched MeSH terms: Microscopy, Electron, Transmission

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