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Fulltext Failure of Glass Fibre-Reinforced Polypropylene Metal Laminate Subjected to Close-Range Explosion

Bassiri Nia A, Xin L, Yahya MY, Ayob A, Farokhi Nejad A, Rahimian Koloor SS, et al.

Polymers (Basel), 2020 Sep 19;12(9).
PMID: 32961655 DOI: 10.3390/polym12092139

The present study investigates the effects of close-range blast loading of fibre metal laminates (FMLs) fabricated from woven glass polypropylene and aluminium alloy 2024-T3. The polypropylene layers and anodized aluminium are stacked in 3/2 layering configuration to investigate the impact energy absorbed through deformation and damage. In order to study the blast responses of FMLs, a 4-cable instrumented pendulum blast set-up is used. Effects of blast impulse and stand-off distance were examined. Investigation of the cross-section of FMLs are presented and damages such as fibre fracture, debonding, and global deformation are examined. Increasing stand-off distance from 4 to 14 mm resulted in a change of damage mode from highly localized perforation to global deformation.

Matched MeSH terms: Aluminum
Applying rhizobacteria consortium for the enhancement of Scirpus grossus growth and phytoaccumulation of Fe and Al in pilot constructed wetlands

Ismail N', Abdullah SRS, Idris M, Kurniawan SB, Effendi Halmi MI, Al Sbani NH, et al.

J Environ Manage, 2020 Aug 01;267:110643.
PMID: 32421674 DOI: 10.1016/j.jenvman.2020.110643

Pilot-scale constructed wetlands planted with Scirpus grossus, were used to investigate the effects of applying a three-rhizobacterial consortium (Bacillus cereus strain NII, Bacillus subtilis strain NII and Brevibacterium sp. strain NII) on the growth of S. grossus and also on the accumulation of iron (Fe) and aluminium (Al) in S. grossus. The experiment includes constructed wetlands with the addition of 2% of the consortium rhizobacteria and without the consortium rhizobacteria addition (acting as control). During each sampling day (0, 5, 10, 15, 20, 25, 30, 42, 72 and 102), plant height, concentration of Fe and Al and sand microbial community were investigated. The results for the constructed wetland with the addition of consortium rhizobacteria showed the growth of S. grossus increased significantly at 26% and 29% for plant height and dry weight, respectively. While the accumulation of Fe and Al in S. grossus were enhanced about 48% and 19% respectively. To conclude, the addition of the rhizobacteria consortium has enhanced both the growth of S. grossus and the metal accumulation. These results suggesting that rhizobacteria has good potential to restore Fe and Al contaminated water in general and particularly for mining wastewater.

Matched MeSH terms: Aluminum
Fulltext Bauxite mining activities: concerns of residents of Bukit Goh to radiation exposure

Norshuhadah Hayat, Inayatullah Shah Sayed

International Journal of Allied Health Sciences, 2018;2(1):265-272.
MyJurnal

Bauxite mining in Kuantan district of Pahang has raised health concerns of communities residing near the mining areas. Bauxite mining and transportation activities have contributed a lot to the pollution of environment. There is a fear among the residents of the areas that whether the soil is free from naturally occurring radioactive substances or not. Therefore, the objective of this study was to detect the presence of natural radioactive elements in the soil of bauxite mining field at Bukit Goh, Kuantan.

Matched MeSH terms: Aluminum Oxide
Fulltext D-Shaped Polarization Maintaining Fiber Sensor for Strain and Temperature Monitoring

Qazi HH, Mohammad AB, Ahmad H, Zulkifli MZ

Sensors (Basel), 2016 Sep 15;16(9).
PMID: 27649195 DOI: 10.3390/s16091505

A D-shaped polarization-maintaining fiber (PMF) as fiber optic sensor for the simultaneous monitoring of strain and the surrounding temperature is presented. A mechanical end and edge polishing system with aluminum oxide polishing film is utilized to perform sequential polishing on one side (lengthwise) of the PMF in order to fabricate a D-shaped cross-section. Experimental results show that the proposed sensor has high sensitivity of 46 pm/µε and 130 pm/°C for strain and temperature, respectively, which is significantly higher than other recently reported work (mainly from 2013) related to fiber optic sensors. The easy fabrication method, high sensitivity, and good linearity make this sensing device applicable in various applications such as health monitoring and spatial analysis of engineering structures.

Matched MeSH terms: Aluminum Oxide
Fulltext Influence of Metakaolin as partially cement replacement minerals on the properties of cement and concrete

Muhd Norhasri Mohd Sidek, Mohd Fadzil Arshad, Megat Azmi Megat Johari, Zaid Mohd Yazid, Amir Khomeiny, R.

Scientific Research Journal, 2012;9(2):0-0.
MyJurnal

Metakaolin is a manufactured pozzolan produced by thermal processing of purified kaolinitic clay using electrical furnace. This study has examined the effect of Metakaolin on the properties of cement and concrete at a replacement level of 0%, 5%, 10% and 15%. The parameters studied were divided into two groups which are chemical compositions, water requirement, setting time and soundness test were carried out for cementitous properties. Workability, compressive strength and bending strength were test for concrete properties. Hardened concrete was cured under different type of curing conditions and tested.. The result showed that the inclusions of Metakaolin as cement replacement minerals have change some of the cementitous and concrete properties. This research reveals, the optimum effect for cementitous and concrete properties for metakaolin was 10%.

Matched MeSH terms: Aluminum Silicates
Fulltext Assessment of metals pollution in sediment cores from the Sabah-Sarawak coastal waters

Zal U’yun Wan Mahmood, Zaharudin Ahmad, Che Abd Rahim Mohamed, Abdul Kadir Ishak, Norfaizal Mohammed

Jurnal Sains Nuklear Malaysia, 2011;23(2):81-94.
MyJurnal

The distribution, enrichment and pollution status of metals in sediment cores from the Sabah-Sarawak coastal waters were studied. Seven sediment cores were taken in July 2004 using a gravity box corer. The metals of Cu, Zn and Pb were analyzed by ICP-MS to assess the pollution status of the sediments. The sediment fine fraction and organic carbon content was also analyzed. Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Pollution Load Index (PLI) was calculated as criteria of possible contamination. The results showed that collected sediments were composed with clay, silt and sand as 12 – 74%, 27 – 72% and 0 – 20%, respectively. Meanwhile, organic carbon contents were relatively low and constant over time, based on sediment depth profiles, and it did not exceed 5% at any sampling station. The average metal concentrations in sediment cores at all sampling station were distributed in the ranges of 1.66 ± 1.36 – 6.61 ± 0.12 μgg-1 for Cu, 26.55 ± 1.04 – 57.94 ± 1.58 μgg-1 for Zn and 3.99 ± 0.10 – 14.48 ± 0.32μgg-1 for Pb. According to calculations of EF, Igeo and PLI, it can be concluded that concentrations of Cu, Zn and Pb were not significantly affected by pollution from anthropogenic sources at the seven sampling locations. Thus, the metal content of Cu, Zn and Pb in sediment should not cause pollution problem to the marine environment of Sabah-Sarawak coastal waters and further response measures are not needed.

Matched MeSH terms: Aluminum Silicates
Fulltext Selective leaching of fe from radioactive malaysian zircon mineral

Meor Yusoff, M.S., Latifah Amin

Journal of Nuclear and Related Technologies, 2009;2009(2):70-77.
MyJurnal

XRF analysis was done on a local zircon samples and the result shows it has a high Fe, Th and U content. The high Fe content in Malaysian zircon had made the mineral to be classified as of a low-grade zircon. Presence of Fe in this mineral may be resulted from clay mineral coating found on the zircon surface. Chemical leaching technique was used for the removal of this Fe and the study also shows that a 600 o C heat pretreatment stage is important for the effectiveness of this process. Other parameters studied are the HCl concentration, leaching temperature and time. By using the optimum leaching parameters, the Fe content had been reduced to 0.049% and thus qualified it to be categorised as a premium grade zircon.

Matched MeSH terms: Aluminum Silicates
Fulltext The effects of CR2O3 addition on microstructure and fracture toughness of ZTA ceramic composite

Ahmad Zahirani Ahmad Azhar, Hasmaliza Mohamed, Mani Maran Ratnam, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2013;2013(2):9-15.
MyJurnal

The microstructure and mechanical properties of ceramic composites produced from alumina, yttria stabilized zirconia and chromia oxide system was investigated. The Cr2O3 weight percent was varied from 0 wt% to 1.0 wt%. Each batch of composition was mixed, uniaxially pressed to 13mm diameter and sintered at 1600 ◦C for 4 h in pressureless conditions. Studies on the effects of the sample microstructures on their mechanical and physical properties such as fracture toughness and bulk density were carried out. Results show that an addition of 0.6 wt% of Cr2O3 produces the best mechanical properties. Furthermore, microstructural observations show that the Al2O3 grain size is significantly dependent on the amount of Cr2O3 additives used. Maximum value obtained with 0.6 wt % Cr2O3 for the fracture toughness is 5.36 MPa.m1/2.

Matched MeSH terms: Aluminum Oxide
Fulltext Intercorrelation of surface free energy and anode capacity of alumnium alloy anodes

Muhamad Daud, Sarimah Mahat, Mohd Sharif Sattar

Journal of Nuclear and Related Technologies, 2006;2006(1):19-24.
MyJurnal

Surface free energies have been evaluated from Young’s moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ~1.47%Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≈ 0.08mA/cm 2 , current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surface free energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum.

Matched MeSH terms: Aluminum
Fulltext Soil plant transfer coefficient of 14C-carbofuran in Brassica sp. vegetable agroecosystem

Nashriyah Mat, Mazleha Maskin, Kubiak, Roland

Journal of Nuclear and Related Technologies, 2006;2006(1):41-50.
MyJurnal

The soil plant transfer coefficient or f factor of 14 C-carbofuran pesticide was studied in outdoor lysimeter experiment consisting of Brassica sp. vegetable crop, riverine alluvial clayey soil and Bungor series sandy loam soil. Soil transfer coefficients at 0-10 cm soil depth were 4.38 + 0.30, 5.76 + 1.04, 0.99 + 0.25 and 2.66 + 0.71; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 0-25 cm soil depth, soil plant transfer coefficients were 8.96 + 0.91, 10.40 + 2.63, 2.34 + 0.68 and 6.19 + 1.40; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 77 days after treatment (DAT), the soil plant transfer coefficient was significantly higher in riverine alluvial soil than Bungor soil whereas shoot and root growth was significantly higher in Bungor soil than in riverine alluvial soil. At both 0-10 cm Brassica sp. rooting depth and 0-25 cm soil depth, the soil plant transfer coefficient was significantly higher in 2X recommended application rate of 14 C-carbofuran as compared to 1X recommended application rate, in both Bungor and riverine alluvial soils.

Matched MeSH terms: Aluminum Silicates
Fulltext Relevance of integrated geophysical methods for site characterization in construction industry - a case of Apa in Badagry, Lagos State, Nigeria

Ishola, K. S., Adeoti, L., Sawyerr, F., Adiat, K. A. N

Pertanika Journal of Science & Technology, 2014;22(2):507-527.
MyJurnal

Detailed geophysical investigations have been carried out using integrated geophysical methods with a view to characterising the subsurface lithologic features that might indicate suitable places for structural developments. An overview of the subsurface resistivity distribution has been achieved employing 8Vertical Electrical Soundings with the Schlumberger array and 4 2D resistivity imaging using Wenner array. In order to constrain the results of the electrical resistivity methods, we carried out a ground magnetic survey along E-W direction using the Proton precession magnetometer at 1m sampling interval. Analysis of well logs data available and VES results showed 4 to 5 geoelectric layers corresponding to sand, clayey sand, clay, silty sand and sandy clay. The 2D resistivity imaging sections showed relative decrease of apparent resistivity with depth implying a geological transition from sand with high resistivity value of about 508Ωm to clay with low resistivity value 16Ωm at depths of 0-20m and 25-50m respectively. The magnetic profiles showed that the study area was characterised by short wavelengths and amplitudes ranging from –3800 to 700 nT. The highs and lows of the magnetic responses occasioned by lithological variations and structural features were magnetically resolved. In view of the identified subsurface structures, the suggested depth to the competent layer is about 20m for low to medium structures while above 50m would be suitable for heavy or massive engineering structures. The use of integrated geophysical methods for the delineation, identification and imaging of the subsurface geological structures which could provide clues to the nature and type of foundation suitable for the development of the study area has been successfully achieved.

Matched MeSH terms: Aluminum Silicates
Effect of Morphology and Size of Halloysite Nanotubes on Functional Pectin Bionanocomposites for Food Packaging Applications

Makaremi M, Pasbakhsh P, Cavallaro G, Lazzara G, Aw YK, Lee SM, et al.

ACS Appl Mater Interfaces, 2017 May 24;9(20):17476-17488.
PMID: 28481104 DOI: 10.1021/acsami.7b04297

Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this study as potential films for food packaging applications. The two types of halloysite nanotubes were long and thin (patch) (200-30 000 nm length) and short and stubby (Matauri Bay) (50-3000 nm length) with different morphological, physical, and dispersibility properties. Both matrix (pectin) and reinforcer (halloysite nanotubes) used in this study are considered as biocompatible, natural, and low-cost materials. Various characterization tests including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, release kinetics, contact angle, and dynamic mechanical analysis were performed to evaluate the performance of the pectin films. Exceptional thermal, tensile, and contact angle properties have been achieved for films reinforced by patch halloysite nanotubes due to the patchy and lengthy nature of these tubes, which form a bird nest structure in the pectin matrix. Matauri Bay halloysite nanotubes were dispersed uniformly and individually in the matrix in low and even high halloysite nanotube concentrations. Furthermore, salicylic acid as a biocidal agent was encapsulated in the halloysite nanotubes lumen to control its release kinetics. On this basis, halloysite nanotubes/salicylic acid hybrids were dispersed into the pectin matrix to develop functional biofilms with antimicrobial properties that can be extended over time. Results revealed that shorter nanotubes (Matauri Bay) had better ability for the encapsulation of salicylic acid into their lumen, while patchy structure and longer tubes of patch halloysite nanotubes made the encapsulation process more difficult, as they might need more time and energy to be fully loaded by salicylic acid. Moreover, antimicrobial activity of the films against four different strains of Gram-positive and Gram-negative bacteria indicated the effective antimicrobial properties of pectin/halloysite functionalized films and their potential to be used for food packaging applications.

Matched MeSH terms: Aluminum Silicates
Fulltext Integration of a Dielectrophoretic Tapered Aluminum Microelectrode Array with a Flow Focusing Technique

Rashid NFA, Deivasigamani R, Wee MFMR, Hamzah AA, Buyong MR

Sensors (Basel), 2021 Jul 21;21(15).
PMID: 34372193 DOI: 10.3390/s21154957

We present the integration of a flow focusing microfluidic device in a dielectrophoretic application that based on a tapered aluminum microelectrode array (TAMA). The characterization and optimization method of microfluidic geometry performs the hydrodynamic flow focusing on the channel. The sample fluids are hydrodynamically focused into the region of interest (ROI) where the dielectrophoresis force (FDEP) is dominant. The device geometry is designed using 3D CAD software and fabricated using the micro-milling process combined with soft lithography using PDMS. The flow simulation is achieved using COMSOL Multiphysics 5.5 to study the effect of the flow rate ratio between the sample fluids (Q1) and the sheath fluids (Q2) toward the width of flow focusing. Five different flow rate ratios (Q1/Q2) are recorded in this experiment, which are 0.2, 0.4, 0.6, 0.8 and 1.0. The width of flow focusing is increased linearly with the flow rate ratio (Q1/Q2) for both the simulation and the experiment. At the highest flow rate ratio (Q1/Q2 = 1), the width of flow focusing is obtained at 638.66 µm and at the lowest flow rate ratio (Q1/Q2 = 0.2), the width of flow focusing is obtained at 226.03 µm. As a result, the flow focusing effect is able to reduce the dispersion of the particles in the microelectrode from 2000 µm to 226.03 µm toward the ROI. The significance of flow focusing on the separation of particles is studied using 10 and 1 µm polystyrene beads by applying a non-uniform electrical field to the TAMA at 10 VPP, 150 kHz. Ultimately, we are able to manipulate the trajectories of two different types of particles in the channel. For further validation, the focusing of 3.2 µm polystyrene beads within the dominant FDEP results in an enhanced manipulation efficiency from 20% to 80% in the ROI.

Matched MeSH terms: Aluminum
Fulltext Eco-Friendly Coagulant versus Industrially Used Coagulants: Identification of Their Coagulation Performance, Mechanism and Optimization in Water Treatment Process

Khairul Zaman N, Rohani R, Izni Yusoff I, Kamsol MA, Basiron SA, Abd Rashid AI

Int J Environ Res Public Health, 2021 08 31;18(17).
PMID: 34501755 DOI: 10.3390/ijerph18179164

The evaluation of complex organic and inorganic coagulant's performances and their relationships could compromise the surface water treatment process time and its efficiency. In this work, process optimization was investigated by comparing an eco-friendly chitosan with the industrially used coagulants namely aluminum sulfate (alum), polyaluminum chloride (PAC), and aluminum chlorohydrate (ACH) in compliance with national drinking water standards. To treat various water samples from different treatment plants with turbidity and pH ranges from 20-826.3 NTU and 5.21-6.80, respectively, 5-20 mg/L coagulant dosages were varied in the presence of aluminum, ferum, and manganese. Among all, 10 mg/L of the respective ACH and chitosan demonstrated 97% and 99% turbidity removal in addition to the removal of the metals that complies with the referred standard. However, chitosan owes fewer sensitive responses (turbidity and residual metal) with the change in its input factors (dosage and pH), especially in acidic conditions. This finding suggested its beneficial role to be used under the non-critical dosage monitoring. Meanwhile, ACH was found to perform better than chitosan only at pH > 7.4 with half dosage required. In summary, chitosan and ACH could perform equally at a different set of optimum conditions. This optimization study offers precise selections of coagulants for a practical water treatment operation.

Matched MeSH terms: Aluminum
Fulltext New Experimental Zirconia-Reinforced Rice Husk Nanohybrid Composite and the Outcome of Its Surface Roughness and Microhardness in Comparison with Commercialized Nanofilled and Microhybrid Composite Resins

Lin GSS, Ghani NRNA, Ismail NH, Singbal K, Noorani TY, Mamat N

Contemp Clin Dent, 2021 03 20;12(1):21-27.
PMID: 33967533 DOI: 10.4103/ccd.ccd_298_20

Background: An ideal composite resin should demonstrate smooth surface after polishing and high hardness value to provide long-term success. Thus, this study aimed to compare the surface roughness and microhardness of new experimental zirconia-reinforced rice husk nanohybrid composite (Zr-Hybrid) with commercialized nanofilled (Filtek-Z350-XT) and microhybrid composite (Zmack-Comp) resins before and after artificial ageing.
Methods: One hundred and eighty standardized disc samples were prepared, of which ninety samples each were used for surface roughness and microhardness test, respectively. They were divided equally into: Group 1 (Filtek-Z350-XT), Group 2 (Zmack-Comp), and Group 3 (Zr-Hybrid). For surface roughness test, all samples were polished with aluminium oxide discs and further subdivided into aged and unaged subgroups, in which composite samples in aged subgroups were subjected to 2500 thermal cycles. Next, all the samples were subjected to surface roughness test using a contact stylus profilometer. As for microhardness test, all the aged and unaged samples were tested using a Vickers hardness machine with a load of 300 kgf for 10 s and viewed under a digital microscope to obtain microhardness value. Data were analyzed using two-way ANOVA followed by post hoc Tukey's honestly significant difference and paired sample t-test with significance level set at P = 0.05.
Results: In both the aged and unaged groups, Zr-Hybrid showed statistically significantly lower surface roughness (P < 0.05) than Filtek-Z350-XT and Zmack-Comp, but no statistically significant difference was noted between Filtek-Z350-XT and Zmack-Comp (P > 0.05). A similar pattern was noted in microhardness test, whereby Zr-Hybrid showed the highest value (P < 0.05) followed by Filtek-Z350-XT and lastly Zmack-Comp. Besides, significant differences in surface roughness and microhardness were noted between the aged and unaged groups.
Conclusion: Zr-Hybrid seems to demonstrate better surface roughness and microhardness value before and after artificial ageing.

Matched MeSH terms: Aluminum Oxide
Fulltext Comments on 'Lattice Boltzmann simulation of alumina-water nanofluid in a square cavity' by Yurong He, Cong Qi, Yanwei Hu, Bin Qin, Fengchen Li and Yulong Ding

Sidik NA, Safdari A

Nanoscale Res Lett, 2012;7(1):648.
PMID: 23176814 DOI: 10.1186/1556-276X-7-648

This work presents some comments concerning the paper entitled 'Lattice Boltzmann simulation of alumina-water nanofluid in a square cavity' by Yurong He, Cong Qi, Yanwei Hu, Bin Qin, Fengchen Li and Yulong Ding which was published in Nanoscale Research Letters in 2011. The comments are related to the numerical parameters and the computed results of average Nusselt number.

Matched MeSH terms: Aluminum Oxide
Synthesis of 4-chlorophenoxyacetate-zinc-aluminium-layered double hydroxide nanocomposite: physico-chemical and controlled release properties

Hussein MZ, Sarijo SH, Yahaya AH, Zainal Z

J Nanosci Nanotechnol, 2007 Aug;7(8):2852-62.
PMID: 17685307

Layered organic-inorganic hybrid nanocomposite material was synthesised using 4-chlorophenoxyacetate (4CPA) as guest anion intercalated into the Zn-Al layered double hydroxide inorganic host by direct co-precipitation method at pH = 7.5 and Zn to Al molar ratio of 4. Both PXRD and FTIR results confirmed that the 4CPA was successfully intercalated into the Zn-AI-LDH interlayer. As a result, a well-ordered nanolayered organic-inorganic hybrid nanocomposite, with the expansion of the basal spacing from 8.9 angstroms in the layered double hydroxide to 20.1 angstroms in the resulting nanocomposite was observed. The FTIR spectrum of the nanocomposite (ZAC) showed that it composed spectral features of Zn-AI-LDH (ZAL) and 4CPA. The nanocomposites synthesized in this work are of mesoporous-type containing 39.8% (w/w) of 4CPA with mole fraction of Al3+ in the inorganic brucite-like layers (xAI) of 0.224. The release studies showed a rapid release of the 4CPA for the first 600 min, and more sustained thereafter. The total amount of 4CPA released from the nanocomposite interlayer into the aqueous solution were 21%, 66%, and 72% in 0.0001, 0.00025, and 0.0005 M sodium carbonate, respectively. In distilled water, about 75, 35, and 57% of 4CPA could be released in 1000 min, when the pH of the release media was set at 3, 6.25, and 12, respectively. In comparison with a structurally similar organic moiety with one more chlorine atom at the 2-position of the aromatic ring, namely 2,4-dichlorophenoxyacetate (24D), the 4CPA showed a slower release rate. The slightly bulkier organic moiety of 24D together with the presence of chlorine atom at the 2-position presumably had contributed to its higher release rate, and it seems that these factors may be exploited for tuning the release rate of intercalated guest anions with similar properties. This study suggests that layered double hydroxide can be used as a carrier for an active agent and the chemical structure of the intercalated moiety can be used to tune the desired release kinetics of the beneficial agent.

Matched MeSH terms: Aluminum/chemistry*; Aluminum Hydroxide/chemistry
Fulltext A tapered aluminium microelectrode array for improvement of dielectrophoresis-based particle manipulation

Buyong MR, Larki F, Faiz MS, Hamzah AA, Yunas J, Majlis BY

Sensors (Basel), 2015;15(5):10973-90.
PMID: 25970255 DOI: 10.3390/s150510973

In this work, the dielectrophoretic force (F(DEP)) response of Aluminium Microelectrode Arrays with tapered profile is investigated through experimental measurements and numerical simulations. A standard CMOS processing technique with a step for the formation of a tapered profile resist is implemented in the fabrication of Tapered Aluminium Microelectrode Arrays (TAMA). The F(DEP) is investigated through analysis of the Clausius-Mossotti factor (CMF) and cross-over frequency (f(xo)). The performance of TAMA with various side wall angles is compared to that of microelectrodes with a straight cut sidewall profile over a wide range of frequencies through FEM numerical simulations. Additionally, electric field measurement (EFM) is performed through scanning probe microscopy (SPM) in order to obtain the region of force focus in both platforms. Results showed that the tapered profile microelectrodes with angles between 60° and 70° produce the highest electric field gradient on the particles. Also, the region of the strongest electric field in TAMA is located at the bottom and top edge of microelectrode while the strongest electric field in microelectrodes with straight cut profile is found at the top corner of the microelectrode. The latter property of microelectrodes improves the probability of capturing/repelling the particles at the microelectrode's side wall.

Matched MeSH terms: Aluminum
Fulltext Gate length variation effect on performance of gate-first self-aligned In₀.₅₃Ga₀.₄₇As MOSFET

Mohd Razip Wee MF, Dehzangi A, Bollaert S, Wichmann N, Majlis BY

PLoS One, 2013;8(12):e82731.
PMID: 24367548 DOI: 10.1371/journal.pone.0082731

A multi-gate n-type In₀.₅₃Ga₀.₄₇As MOSFET is fabricated using gate-first self-aligned method and air-bridge technology. The devices with different gate lengths were fabricated with the Al2O3 oxide layer with the thickness of 8 nm. In this letter, impact of gate length variation on device parameter such as threshold voltage, high and low voltage transconductance, subthreshold swing and off current are investigated at room temperature. Scaling the gate length revealed good enhancement in all investigated parameters but the negative shift in threshold voltage was observed for shorter gate lengths. The high drain current of 1.13 A/mm and maximum extrinsic transconductance of 678 mS/mm with the field effect mobility of 364 cm(2)/Vs are achieved for the gate length and width of 0.2 µm and 30 µm, respectively. The source/drain overlap length for the device is approximately extracted about 51 nm with the leakage current in order of 10(-8) A. The results of RF measurement for cut-off and maximum oscillation frequency for devices with different gate lengths are compared.

Matched MeSH terms: Aluminum Oxide
Mobility Studies of (14)C-Chlorpyrifos in Malaysian Oil Palm Soils

Halimah M, Ismail BS, Nashriyah M, Maznah Z

Bull Environ Contam Toxicol, 2016 Jan;96(1):120-4.
PMID: 26546229 DOI: 10.1007/s00128-015-1685-3

The mobility of (14)C-chlorpyrifos using soil TLC was investigated in this study. It was found that chlorpyrifos was not mobile in clay, clay loam and peat soil. The mobility of (14)C-chlorpyrifos and non-labelled chlorpyrifos was also tested with silica gel TLC using three types of developing solvent hexane (100%), hexane:ethyl acetate (95:5, v/v); and hexane:ethyl acetate (98:2, v/v). The study showed that both the (14)C-labelled and non-labelled chlorpyrifos have the same Retardation Factor (Rf) for different developing solvent systems. From the soil column study on mobility of chlorpyrifos, it was observed that no chlorpyrifos residue was found below 5 cm depth in three types of soil at simulation rainfall of 20, 50 and 100 mm. Therefore, the soil column and TLC studies have shown similar findings in the mobility of chlorpyrifos.

Matched MeSH terms: Aluminum Silicates

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