Displaying publications 101 - 120 of 403 in total

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  1. Fulltext The influence of lightning induced voltage on the distribution power line polymer insulators
    Izadi M, Abd Rahman MS, Ab-Kadir MZ, Gomes C, Jasni J, Hajikhani M
    PLoS One, 2017;12(2):e0172118.
    PMID: 28234930 DOI: 10.1371/journal.pone.0172118
    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance.
    Matched MeSH terms: Equipment Design
  2. Fulltext Real-time gas identification by analyzing the transient response of capillary-attached conductive gas sensor
    Bahraminejad B, Basri S, Isa M, Hambli Z
    Sensors (Basel), 2010;10(6):5359-77.
    PMID: 22219666 DOI: 10.3390/s100605359
    In this study, the ability of the Capillary-attached conductive gas sensor (CGS) in real-time gas identification was investigated. The structure of the prototype fabricated CGS is presented. Portions were selected from the beginning of the CGS transient response including the first 11 samples to the first 100 samples. Different feature extraction and classification methods were applied on the selected portions. Validation of methods was evaluated to study the ability of an early portion of the CGS transient response in target gas (TG) identification. Experimental results proved that applying extracted features from an early part of the CGS transient response along with a classifier can distinguish short-chain alcohols from each other perfectly. Decreasing time of exposition in the interaction between target gas and sensing element improved the reliability of the sensor. Classification rate was also improved and time of identification was decreased. Moreover, the results indicated the optimum interval of the early transient response of the CGS for selecting portions to achieve the best classification rates.
    Matched MeSH terms: Equipment Design
  3. An overview of landfill leachate treatment via activated carbon adsorption process
    Foo KY, Hameed BH
    J Hazard Mater, 2009 Nov 15;171(1-3):54-60.
    PMID: 19577363 DOI: 10.1016/j.jhazmat.2009.06.038
    Water scarcity and pollution rank equal to climate change as the most urgent environmental issue for the 21st century. To date, the percolation landfill leachate into the groundwater tables and aquifer systems which poses a potential risk and potential hazards towards the public health and ecosystems, remains an aesthetic concern and consideration abroad the nations. Arising from the steep enrichment of globalization and metropolitan growth, numerous mitigating approaches and imperative technologies have currently drastically been addressed and confronted. Confirming the assertion, this paper presents a state of art review of leachate treatment technologies, its fundamental background studies, and environmental implications. Moreover, the key advance of activated carbons adsorption, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbons adsorption represents a potentially viable and powerful tool, leading to the superior improvement of environmental conservation.
    Matched MeSH terms: Equipment Design
  4. Fixed-bed adsorption of reactive azo dye onto granular activated carbon prepared from waste
    Ahmad AA, Hameed BH
    J Hazard Mater, 2010 Mar 15;175(1-3):298-303.
    PMID: 19883979 DOI: 10.1016/j.jhazmat.2009.10.003
    In this work, the adsorption potential of bamboo waste based granular activated carbon (BGAC) to remove C.I. Reactive Black (RB5) from aqueous solution was investigated using fixed-bed adsorption column. The effects of inlet RB5 concentration (50-200mg/L), feed flow rate (10-30 mL/min) and activated carbon bed height (40-80 mm) on the breakthrough characteristics of the adsorption system were determined. The highest bed capacity of 39.02 mg/g was obtained using 100mg/L inlet dye concentration, 80 mm bed height and 10 mL/min flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models namely, Adam's-Bohart, Thomas and Yoon-Nelson models. The results fitted well to the Thomas and Yoon-Nelson models with coefficients of correlation R(2)>or=0.93 at different conditions. The BGAC was shown to be suitable adsorbent for adsorption of RB5 using fixed-bed adsorption column.
    Matched MeSH terms: Equipment Design
  5. Detoxification of pesticide waste via activated carbon adsorption process
    Foo KY, Hameed BH
    J Hazard Mater, 2010 Mar 15;175(1-3):1-11.
    PMID: 19879688 DOI: 10.1016/j.jhazmat.2009.10.014
    Concern about environmental protection has increased over the years from a global viewpoint. To date, the percolation of pesticide waste into the groundwater tables and aquifer systems remains an aesthetic issue towards the public health and food chain interference. With the renaissance of activated carbon, there has been a consistent growing interest in this research field. Confirming the assertion, this paper presents a state of art review of pesticide agrochemical practice, its fundamental characteristics, background studies and environmental implications. Moreover, the key advance of activated carbon adsorption, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbon adsorption represents a plausible and powerful circumstance, leading to the superior improvement of environmental preservation.
    Matched MeSH terms: Equipment Design
  6. Fulltext Humidity sensors principle, mechanism, and fabrication technologies: a comprehensive review
    Farahani H, Wagiran R, Hamidon MN
    Sensors (Basel), 2014 Apr 30;14(5):7881-939.
    PMID: 24784036 DOI: 10.3390/s140507881
    Humidity measurement is one of the most significant issues in various areas of applications such as instrumentation, automated systems, agriculture, climatology and GIS. Numerous sorts of humidity sensors fabricated and developed for industrial and laboratory applications are reviewed and presented in this article. The survey frequently concentrates on the RH sensors based upon their organic and inorganic functional materials, e.g., porous ceramics (semiconductors), polymers, ceramic/polymer and electrolytes, as well as conduction mechanism and fabrication technologies. A significant aim of this review is to provide a distinct categorization pursuant to state of the art humidity sensor types, principles of work, sensing substances, transduction mechanisms, and production technologies. Furthermore, performance characteristics of the different humidity sensors such as electrical and statistical data will be detailed and gives an added value to the report. By comparison of overall prospects of the sensors it was revealed that there are still drawbacks as to efficiency of sensing elements and conduction values. The flexibility offered by thick film and thin film processes either in the preparation of materials or in the choice of shape and size of the sensor structure provides advantages over other technologies. These ceramic sensors show faster response than other types.
    Matched MeSH terms: Equipment Design
  7. Fulltext An electronic nose for reliable measurement and correct classification of beverages
    Mamat M, Samad SA, Hannan MA
    Sensors (Basel), 2011;11(6):6435-53.
    PMID: 22163964 DOI: 10.3390/s110606435
    This paper reports the design of an electronic nose (E-nose) prototype for reliable measurement and correct classification of beverages. The prototype was developed and fabricated in the laboratory using commercially available metal oxide gas sensors and a temperature sensor. The repeatability, reproducibility and discriminative ability of the developed E-nose prototype were tested on odors emanating from different beverages such as blackcurrant juice, mango juice and orange juice, respectively. Repeated measurements of three beverages showed very high correlation (r > 0.97) between the same beverages to verify the repeatability. The prototype also produced highly correlated patterns (r > 0.97) in the measurement of beverages using different sensor batches to verify its reproducibility. The E-nose prototype also possessed good discriminative ability whereby it was able to produce different patterns for different beverages, different milk heat treatments (ultra high temperature, pasteurization) and fresh and spoiled milks. The discriminative ability of the E-nose was evaluated using Principal Component Analysis and a Multi Layer Perception Neural Network, with both methods showing good classification results.
    Matched MeSH terms: Equipment Design
  8. Fulltext Quantification of mesenchymal stem cell growth rates through secretory and excretory biomolecules in conditioned media via Fresnel reflection
    Ahmad H, Thambiratnam K, Zulkifli AZ, Lawrence A, Jasim AA, Kunasekaran W, et al.
    Sensors (Basel), 2013 Sep 30;13(10):13276-88.
    PMID: 24084118 DOI: 10.3390/s131013276
    An efficient and low cost optical method for directly measuring the concentration of homogenous biological solutes is proposed and demonstrated. The proposed system operates by Fresnel reflection, with a flat-cleaved single-mode fiber serving as the sensor probe. A laser provides a 12.9 dBm sensor signal at 1,550 nm, while a computer-controlled optical power meter measures the power of the signal returned by the probe. Three different mesenchymal stem cell (MSC) lines were obtained, sub-cultured and trypsinized daily over 9 days. Counts were measured using a haemocytometer and the conditioned media (CM) was collected daily and stored at -80 °C. MSCs release excretory biomolecules proportional to their growth rate into the CM, which changes the refractive index of the latter. The sensor is capable of detecting changes in the number of stem cells via correlation to the change in the refractive index of the CM, with the measured power loss decreasing approximately 0.4 dB in the CM sample per average 1,000 cells in the MSC subculture. The proposed system is highly cost-effective, simple to deploy, operate, and maintain, is non-destructive, and allows reliable real-time measurement of various stem cell proliferation parameters.
    Matched MeSH terms: Equipment Design
  9. Multi-wavelength laser generation with Bismuthbased Erbium-doped fiber
    Ahmad H, Shahi S, Harun SW
    Opt Express, 2009 Jan 05;17(1):203-7.
    PMID: 19129889
    A multi-wavelength laser comb is demonstrated using a nonlinear effect in a backward pumped Bismuth-based Erbium-doped fiber (Bi-EDF) for the first time. It uses a ring cavity resonator scheme containing a 215 cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10 dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.
    Matched MeSH terms: Equipment Design
  10. Performance evaluation of supported ionic liquid membrane for removal of phenol
    Nosrati S, Jayakumar NS, Hashim MA
    J Hazard Mater, 2011 Sep 15;192(3):1283-90.
    PMID: 21752542 DOI: 10.1016/j.jhazmat.2011.06.037
    This work evaluates the performance of ionic liquid in supported liquid membrane (SLM) for the removal of phenol from wastewater. Ionic liquids are organic salts entirely composed of organic cations and either organic or inorganic anions. Due to the fact that the vapor pressure of ionic liquid is not detectable and they are sparingly soluble in most conventional solvents, they can be applied in SLM as the organic phase. In this work, 1-n-alkyl-3-methylimidazolium salts, [C(n)MIM](+)[X](-) have been investigated so as to determine an optimal supported ionic liquid membrane. The effect of operational parameters such as pH, stirring speed and the concentration of stripping agent has been studied, and an evaluation of different membrane supports were also carried out. With a minimal amount of the ionic liquid 1-Butyl-3-methylimidazolium hydrogensulfate, 85% phenol removal could be achieved by using polytetrafluoroethylene hydrophobic membrane filter in the SLM.
    Matched MeSH terms: Equipment Design
  11. Novel Multipin Electrode Cap System for Dry Electroencephalography
    Fiedler P, Pedrosa P, Griebel S, Fonseca C, Vaz F, Supriyanto E, et al.
    Brain Topogr, 2015 Sep;28(5):647-656.
    PMID: 25998854 DOI: 10.1007/s10548-015-0435-5
    Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.
    Matched MeSH terms: Equipment Design/instrumentation*
  12. Microfluidic formation of highly monodispersed multiple cored droplets using needle-based system in parallel mode
    Lian Z, Chan Y, Luo Y, Yang X, Koh KS, Wang J, et al.
    Electrophoresis, 2020 06;41(10-11):891-901.
    PMID: 31998972 DOI: 10.1002/elps.201900403
    Scale-up in droplet microfluidics achieved by increasing the number of devices running in parallel or increasing the droplet makers in the same device can compromise the narrow droplet-size distribution, or requires high fabrication cost, when glass- or polymer-based microdevices are used. This paper reports a novel way using parallelization of needle-based microfluidic systems to form highly monodispersed droplets with enhanced production rates yet in cost-effective way, even when forming higher order emulsions with complex inner structure. Parallelization of multiple needle-based devices could be realized by applying commercially available two-way connecters and 3D-printed four-way connectors. The production rates of droplets could be enhanced around fourfold (over 660 droplets/min) to eightfold (over 1300 droplets/min) by two-way connecters and four-way connectors, respectively, for the production of the same kind of droplets than a single droplet maker (160 droplets/min). Additionally, parallelization of four-needle sets with each needle specification ranging from 34G to 20G allows for simultaneous generation of four groups of PDMS microdroplets with each group having distinct size yet high monodispersity (CV < 3%). Up to six cores can be encapsulated in double emulsion using two parallelly connected devices via tuning the capillary number of middle phase in a range of 1.31 × 10-4 to 4.64 × 10-4 . This study leads to enhanced production yields of droplets and enables the formation of groups of droplets simultaneously to meet extensive needs of biomedical and environmental applications, such as microcapsules with variable dosages for drug delivery or drug screening, or microcapsules with wide range of absorbent loadings for water treatment.
    Matched MeSH terms: Equipment Design
  13. Fulltext An amperometric biosensor utilizing a ferrocene-mediated horseradish peroxidase reaction for the determination of capsaicin (chili hotness)
    Mohammad R, Ahmad M, Heng LY
    Sensors (Basel), 2013 Aug 05;13(8):10014-26.
    PMID: 23921830 DOI: 10.3390/s130810014
    Chili hotness is very much dependent on the concentration of capsaicin present in the chili fruit. A new biosensor based on a horseradish peroxidase enzyme-capsaicin reaction mediated by ferrocene has been successfully developed for the amperometric determination of chili hotness. The amperometric biosensor is fabricated based on a single-step immobilization of both ferrocene and horseradish peroxidase in a photocurable hydrogel membrane, poly(2-hydroxyethyl methacrylate). With mediation by ferrocene, the biosensor could measure capsaicin concentrations at a potential 0.22 V (vs. Ag/AgCl), which prevented potential interference from other electroactive species in the sample. Thus a good selectivity towards capsaicin was demonstrated. The linear response range of the biosensor towards capsaicin was from 2.5-99.0 µM with detection limit of 1.94 µM. A good relative standard deviation (RSD) for reproducibility of 6.4%-9.9% was obtained. The capsaicin biosensor demonstrated long-term stability for up to seven months. The performance of the biosensor has been validated using a standard method for the analysis of capsaicin based on HPLC.
    Matched MeSH terms: Equipment Design
  14. Fast prototype of a wireless cardiac rhythm interpretive instrument
    Wong KI, Ho MM
    Annu Int Conf IEEE Eng Med Biol Soc, 2008;2008:502-5.
    PMID: 19162703 DOI: 10.1109/IEMBS.2008.4649200
    Extended patient monitoring has become increasingly important for detection of cardiac conditions, such as irregularities in the rhythms of the heart, while patient is practicing normal daily activity. This paper presents a design of a single lead wireless cardiac rhythm interpretive instrument that capable of capture the electrocardiogram (ECG) in digital format and transmitted to a remote base-station (i.e. PC) for storage and further interpretation. The design has achieved high quality of ECG and free of interference in the presence of motion.
    Matched MeSH terms: Equipment Design
  15. Fulltext Seismic performance of RC beam-column connections with continuous rectangular spiral transverse reinforcements for low ductility classes
    Azimi M, Bin Adnan A, Sam AR, Tahir MM, Faridmehr I, Hodjati R
    ScientificWorldJournal, 2014;2014:802605.
    PMID: 25309957 DOI: 10.1155/2014/802605
    The seismic performance of RC columns could be significantly improved by continuous spiral reinforcement as a result of its adequate ductility and energy dissipation capacity. Due to post-earthquake brittle failure observations in beam-column connections, the seismic behaviour of such connections could greatly be improved by simultaneous application of this method in both beams and columns. In this study, a new proposed detail for beam to column connection introduced as "twisted opposing rectangular spiral" was experimentally and numerically investigated and its seismic performance was compared against normal rectangular spiral and conventional shear reinforcement systems. In this study, three full scale beam to column connections were first designed in conformance with Eurocode (EC2-04) for low ductility class connections and then tested by quasistatic cyclic loading recommended by ACI Building Code (ACI 318-02). Next, the experimental results were validated by numerical methods. Finally, the results revealed that the new proposed connection could improve the ultimate lateral resistance, ductility, and energy dissipation capacity.
    Matched MeSH terms: Equipment Design
  16. Complications after tenckhoff catheter insertion: a single-centre experience using multiple operators over four years
    Liu WJ, Hooi LS
    Perit Dial Int, 2010 03 12;30(5):509-12.
    PMID: 20228175 DOI: 10.3747/pdi.2009.00083
    OBJECTIVE: To analyze the complications after Tenckhoff catheter insertion among patients with renal failure needing dialysis. ♢

    PATIENTS AND METHODS: The open, paramedian approach is the commonest technique to insert the 62-cm coiled double-cuffed Tenckhoff peritoneal catheter. All patients with catheters inserted between January 2004 and November 2007 were retrospectively analyzed for demographics and followed for up to 1 month for complications. We excluded patients whose catheters had been anchored to the bladder wall and who underwent concurrent omentectomy or readjustment without removal of a malfunctioning catheter (n = 7). Intravenous cloxacillin was the standard preoperative antibiotic prophylaxis. ♢

    RESULTS: Over the 4-year study period, 384 catheters were inserted under local anesthetic into 319 patients [201 women (62.8%); mean age: 49.4 ± 16.7 years (range: 13 - 89 years); 167 (52.2%) with diabetes; 303 (95%) with end-stage renal disease] by 22 different operators. All Tenckhoff catheters were inserted by the general surgical (n = 223) or urology (n = 161) team. There were 29 cases (7.6%) of catheter migration, 22 (5.7%) of catheter obstruction without migration, 24 (6.3%) of exit-site infection, 12 (3.1%) of leak from the main incision, 14 (3.6%) of culture-proven wound infection, 11 (2.9%) post-insertion peritonitis, and 1 (0.3%) hemoperitoneum. No deaths were attributed to surgical mishap. ♢

    CONCLUSIONS: The most common complication was catheter migration. The paramedian insertion technique was safe, with low complication rates.

    Matched MeSH terms: Equipment Design
  17. Fulltext Enhanced ethanol gas sensing properties of SnO₂-core/ZnO-shell nanostructures
    Tharsika T, Haseeb AS, Akbar SA, Sabri MF, Hoong WY
    Sensors (Basel), 2014;14(8):14586-600.
    PMID: 25116903 DOI: 10.3390/s140814586
    An inexpensive single-step carbon-assisted thermal evaporation method for the growth of SnO2-core/ZnO-shell nanostructures is described, and the ethanol sensing properties are presented. The structure and phases of the grown nanostructures are investigated by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. XRD analysis indicates that the core-shell nanostructures have good crystallinity. At a lower growth duration of 15 min, only SnO2 nanowires with a rectangular cross-section are observed, while the ZnO shell is observed when the growth time is increased to 30 min. Core-shell hierarchical nanostructures are present for a growth time exceeding 60 min. The growth mechanism for SnO2-core/ZnO-shell nanowires and hierarchical nanostructures are also discussed. The sensitivity of the synthesized SnO2-core/ZnO-shell nanostructures towards ethanol sensing is investigated. Results show that the SnO2-core/ZnO-shell nanostructures deposited at 90 min exhibit enhanced sensitivity to ethanol. The sensitivity of SnO2-core/ZnO-shell nanostructures towards 20 ppm ethanol gas at 400 °C is about ~5-times that of SnO2 nanowires. This improvement in ethanol gas response is attributed to high active sensing sites and the synergistic effect of the encapsulation of SnO2 by ZnO nanostructures.
    Matched MeSH terms: Equipment Design/methods
  18. Fulltext A soft artificial muscle driven robot with reinforcement learning
    Yang T, Xiao Y, Zhang Z, Liang Y, Li G, Zhang M, et al.
    Sci Rep, 2018 09 28;8(1):14518.
    PMID: 30266999 DOI: 10.1038/s41598-018-32757-9
    Soft robots driven by stimuli-responsive materials have their own unique advantages over traditional rigid robots such as large actuation, light weight, good flexibility and biocompatibility. However, the large actuation of soft robots inherently co-exists with difficulty in control with high precision. This article presents a soft artificial muscle driven robot mimicking cuttlefish with a fully integrated on-board system including power supply and wireless communication system. Without any motors, the movements of the cuttlefish robot are solely actuated by dielectric elastomer which exhibits muscle-like properties including large deformation and high energy density. Reinforcement learning is used to optimize the control strategy of the cuttlefish robot instead of manual adjustment. From scratch, the swimming speed of the robot is enhanced by 91% with reinforcement learning, reaching to 21 mm/s (0.38 body length per second). The design principle behind the structure and the control of the robot can be potentially useful in guiding device designs for demanding applications such as flexible devices and soft robots.
    Matched MeSH terms: Equipment Design
  19. Fulltext COVID-19 face mask valve for nasal and laryngeal endoscopy
    Gendeh HS, Husain S
    Ann R Coll Surg Engl, 2021 Jul;103(7):536-537.
    PMID: 33913780 DOI: 10.1308/rcsann.2021.0009
    Matched MeSH terms: Equipment Design
  20. Sensitive detection of multiple pathogens using a single DNA probe
    Nordin N, Yusof NA, Abdullah J, Radu S, Hushiarian R
    Biosens Bioelectron, 2016 Dec 15;86:398-405.
    PMID: 27414245 DOI: 10.1016/j.bios.2016.06.077
    A simple but promising electrochemical DNA nanosensor was designed, constructed and applied to differentiate a few food-borne pathogens. The DNA probe was initially designed to have a complementary region in Vibrio parahaemolyticus (VP) genome and to make different hybridization patterns with other selected pathogens. The sensor was based on a screen printed carbon electrode (SPCE) modified with polylactide-stabilized gold nanoparticles (PLA-AuNPs) and methylene blue (MB) was employed as the redox indicator binding better to single-stranded DNA. The immobilization and hybridization events were assessed using differential pulse voltammetry (DPV). The fabricated biosensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0×10(-9)-2.0×10(-13)M with a detection limit of 5.3×10(-12)M. The relative standard deviation for 6 replications of DPV measurement of 0.2µM complementary DNA was 4.88%. The fabricated DNA biosensor was considered stable and portable as indicated by a recovery of more than 80% after a storage period of 6 months at 4-45°C. Cross-reactivity studies against various food-borne pathogens showed a reliably sensitive detection of VP.
    Matched MeSH terms: Equipment Design
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