A simple voltammetric technique for quantification of chromium(VI) is presented in this work. The technique is based on linear sweep voltammetric reduction Cr(VI) on hexadecyltrimethylammonium bromide (HDTMABr) modified Lampung zeolite carbonpasteelectrode. Selected HDTMABr concentration for natural zeolite modification is obtained 200 mM. Working electrode for chromium(VI) detection is made by graphite, paraffin oil and HDTMABr modified Lampung zeolite. The effect of supporting electrolyte matrix, pH and also scan rate is also investigated. The calibration curve for chromium(VI) detection using the proposed method shows linearity from 0.2 to 1.0 mM with sensitivity, detection and quantification limit, and precision was 0.4294 mM, 3.63 x 10 -4 mM, 1.197 x 10 -3 mM, 4.49%, respectively.
Research about creating of carbonpasteelectrode modified by curcumin for detecting of uric acid has been conducted. Causing improperly condition, the research has been changed with another method, so the focus of research is “Immobilizations of HRP-Uricase Enzyme on Silica Material based on Sol-Gel as Biosensor for detecting of uric acid”.
Chromium exists in the environment especially in two stable species, namely Cr(III) and Cr(VI). Cr(VI) has a higher toxicity than Cr(III). The existing determination method could not distinguish the two species of chromium. It is necessary to differentiate the two, especially for Cr(VI) measurement. Zeolites- iron modified carbonpasteelectrode was developed for the voltammetric determination of Cr(VI). The electrode was made by mixing graphite powder, iron modified zeolites, and paraffin oil. The measurement of Cr(VI) was carried out by cyclic voltammetry at -1.2 V to 1.2 V. KCl 0.05 M solution was used as the electrolyte solution. The electrodes were characterized based on the effect of analyte acidity, preconcentration time, and zeolite-iron composition. The optimum measurement of the Cr (VI) was at pH 3, 25 minutes preconcentration time, and 20% weight composition of zeolites-iron, that yield the highest reduction current was 5.22 μ A at Cr (VI) 50 μM.
Organic ligands have been widely used to modify carbonpasteelectrode because most of them contain N- and S-based complexing center . It is well known that N- and S-based ligands coordinated selectively with transition and heavy metals . The 3-methyl-2-hydrazinobenzothiazole (MBTH) ligand also contains N- and S-based complexing center which can be suitable for formation complexes with La(III). Therefore, we developed an effective, simple, and sensitive differential adsorptive stripping voltammetry for the determination of La(III) in real samples.
To achieve efficient electron transfer, the use of GOx has been often combined with mediator compounds as electrodes. Carbonpaste modified by nanofiber-polyaniline is used in this study as mediator. Carbon is usually considered due to its biocompatibility, chemical stability and conductivity (not corrosive so that does not affect to the performance of the biological culture) . Polyaniline is a common material for manufacturing electrodes such as biosensors, biofuel cells, and super capacitor applications in nano composite forms . In this study, nanofiber-polyaniline has been synthesized in an emeraldine salt form by the interfacial polymerization method. The addition of polyaniline into the carbonpaste aims to counteract the empty spaces amongst the graphite particles. Of course, it will improve the electricity conductivity on the electrode because the electron can be transferred continuously. In addition, the graphite can function to reduce friction so that the current endurance can be increase. This study reports for an efficient, simple and cost effective method for the functional immobilization of GOx onto nanofiber- polyaniline-modified carbon-paste-electrode surfaces which can act as bioanodes in fuel cell applications. In particular, GOx is immobilized onto the electrode surface using glutaraldehyde as a linker molecule.
pulse potential in the range of -1000 to 1000 mV. Based on scanning electron microscopy - energy dispersive x-ray (SEM-EDX), the zeolite-acetylpiridin has a hollow structure; composed of oxygen, carbon, silicon, aluminum, potassium, iron, and chromium atoms. The carbonpasteelectrode that was modified by zeolite-acetylpiridin showed higher intensity of reduction peak. The best working electrode to produce current responses of analyte was EPKZA20 (carbonpasteelectrode modified by 20% zeolite-acetylpyridine). EPKZA20 with preconcentration time for 15 minutes produces the peak current of 2.46 A for chromium (III) concentration of 1 mM.
The structure of MHBT and MBTH is relative same, so the function as ligand will be same. For the reason, we will use the MBTH as active membrane in carbon active membrane for absorptive voltammetry. Coudury  and Muji Harsini, et all  was prepare carbon coated electrode with alizarin as active membrane can be sensor for lanthanum in picomolar (pM) order. Election of carbonpasteelectrode as working electrode because it is easily to be prepared, can adsorb organic compound, inert and therefore not easily to be oxidized and reduced. Thus, this method is expected to increase the sensitivity of analysis. Parameters which were learned include the accumulation potential, the accumulation time, solution pH, precision, limit of detection, linearity, sensitivity, and recovery.
deposition potensial -1.5 V, deposition time 90 seconds, scan rate 0.05 V/s and amplitude modulation 0.05 V. The regression equation and correlation coefficient are y = 0.142 + 0.004x and r = 0.9955, respectively. The resulting calibration plots is linear over the range from 0.5 to 75 ppb. The reproducibility of the AuNPs-GCE was estimated from the response to each 1 ppb of Cr(III) at replicates measurements. This series yield a mean current response, referred to as sensitivity, of 0.14 µA ppb-1 corresponding to a relative standard deviation (RSD) of 2.4%. The detection limit is 0.01 ppb based on three times the standard deviation of the baseline, calculated according to the reference . The calculated detection limit of the proposed method is better than previous reported methods including the Cr(III) determination using sophisticated ICP–MS (Table 1). Usage of AuNPs modified electrode gives at least one order of magnitude better detection limit than previous reported voltrametric methods using film electrodes. Limited publication of Cr(III) voltammetric detection compared with those of Cr(VI), in addition to its relatively poor sensitivity of non-gold electrodes lead us to infer that to obtain high quality of Cr(III) voltammetric profiles require gold or gold-modified electrodes. Previously it is known that high quality voltammetric profiles for Cr(III) oxidation were found to appear only at a gold electrode .
Unitor ACA-384 is a DC electrode for gouging by the air-arc method. In this process, the arc is used to melt the metal, and the molten metal is then blown away by a jet of compressed air. This method has several advan- tages – it can be used for cutting stainless steel and other materials which are difficult to cut with an oxy- acetylene torch. Most of those who have had some welding or cutting experience should be able to master the gouging technique by practising or 3 times a day for about a week. A typical application of the air-arc method is the removal of sections which have been welded to the deck for securing deck cargo (flushing). Hold the electrode holder so that the electrode slopes back from the direction of travel. The air blast is directed along the rear of the elec- trode towards the arc. The depth and contour of the groove is controlled by the electrode angle and speed of travel. It is possible to cut grooves with a depth of up to 5 mm. A com- bination of wide electrode angle and slow speed of travel will produce a narrow, deep groove. The width of the groove will usually be about 3 mm wider than the electrode diameter. An electrode angle of approx. 35° will provide a normal groove depth and highest speed of travel. An electrode angle of 45–70° is used to obtain the deepest groove. Adjust the speed of travel to obtain an even, hissing sound and clean, smooth groove sur- face. The amount of metal which can be removed increases with increasing current. However, every electrode has an ideal current level which is slightly below its maximum. If the ideal level is exceeded, the welder will notice a considerable increase in electrode consumption.
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Berdasarkan pengujian yang dilakukan oleh tabloid otomotif (Otomotif, Edisi Nomor 51 April 2010) menunjukkan adanya peningkatan performa pada sepeda motor menggunakan busi berbahan iridium dibandingkan dengan memakai busi standar. Namun demikian pengujian yang dilakukan oleh tabloid Otomotif belum melakukan pengujian terhadap konsumsi bahan bakar dan emisi gas buang. Oleh karena itu, penelitian ini dilakukan untuk mengetahui pengaruh pemakaian busi berbahan platinum, iridium, serta busi dengan electrode ganda dan multi electrode terhadap konsumsi bahan bakar dan emisi gas buang sepeda motor.
The chromium(VI) and chromium(III) depositionson thegold nanoparticles (AuNPs)-modified glassy carbonelectrode (GCE) from aqueous solutions were studied by means of cyclic voltammetry technique. The deposition processes were investigated at +25°C. The anodic and cathodic scannings were recorded within the potential range of -500 to 1500 mV. The scan rate and multiple cycling were carried out to examine the behavior of the electroactive species on the electrode surface. The logarithmic of the plot between Ip and V reflected a diffusion controlled by the irreversible redox reaction of Cr(III) and an adsorption-driven process. These results strongly suggested that the irreversible redox reaction of Cr(VI) was controlled by the diffusion step.
Setelah dilakukan pengujian keseluruhan alat kepada subyek menggunakan dua jenis electrode yaitu electrode jenis bubble dan electrode jenis disposable dapat terlihat bahwa algoritma yang digunakan sudah cukup baik namun ketika menggunakan electrode bubble yang secara fisik tidak menempel secarakeseluruhan pada kulit mengakibatnya terjadi kesalahan deteksi serta adanya noise yang disebabkan karena getaran yang ditimbulkan oleh electrode bubble ketika subyek berlari dengan kecepatan yang tinggi. Di sisi lain dengan menggunakan electrode jenis disposable hasil pengukuran pada subyek terlihat sangat baik karena kesalahan pendeteksian hampir tidak ada sama sekali karena electrode jenis ini secara fisik menempel erat kepada kulit sehingga tidak menimbulkan banyak getaran. Berdasarkan hasil pengukuran dari semua subyek dengan menggunakan dua jenis electrode tersebut juga dapat terlihat bahwa posisi peletakan electrode juga sangat berpengaruh untuk hasil pengukuran ECG maupun heart rate. Sisa subyek yang datanya belum dimasukkan pada bab ini, telah dimasukkan bentuk sinyal ECGnya pada bab lampiran.
Dye-sensitized dye-based solar cells (DSSC) are widely developed due to their low-cost and simple fabrication processes. Some of the issues that challenge the DSSC fabrication are low efficiency. In this study developed DSSC using monolithic type configuration. The method used is screen printing method and the parameters studied include the effect of variation of ZrO2 thickness that is 1x, 2x, 3x, and 6x coating and influence of carbon and platinum counter electrode to the efficiency of solar cell. The results of this study were characterized by surface morphological properties and sheet resistance values using SEM, EDS and four point probe respectively. Morphological characterization is done by comparing the morphology of carbon and platinum counter electrodes which show that carbon has a larger particle structure than platinum and see the ZrO2 material content which shows that there is no material other than Zr, O, and Ti. The result of sheet resistance characterization shows that the average value of car bon resistance is 9,864 Ω / sq and platinum is 10,954 Ω / sq so that the carbon resistance value is lower than platinum. With the lower resistance the better solar cell performance.
Soil naturally contains energy conductive of microbial fuel cells that capable of generating dc supply voltage. Soil is used as the medium of conducting the small output voltage. The types of soil contain different rate of electrical resistivity and conductivity value. The selection of the clay soil is due to the low resistivity and high moisture content. Electrode made of metal is used to check the potential difference of the soil. The design of clay soil with electrode of anode and cathode which made from copper and aluminium respectively can produce low output voltage. The higher of electrical conductivity of metal may influence the choosing of electrode. The arrangements which are series, parallel and series- parallel (cascade) are implementing in this project. The arrangement of dc supply of clay soil will help to optimize the output voltage. The optimization of the DC supply form clay soil will be check and test by connect small load of LED. The consideration of arrangement of cell, effect of clay soil in temperature, the pH value of clay soil, and arrangement of circuit of the cell must take in order to get the value of output voltage. The output voltage should be increase based on the value of earth battery cell can be constructing in this case study.
electrode (cathode / WE). The mixture will be polymerized with nickel electrodes shaped thin plates and thin beam-shaped carbonelectrode. Flow synthesis given by 4 mA with synthesis time for 30 minutes. PANI/ HCl formed will be attached to the carbonelectrode in the form of a layer having a thickness of tens of micrometers formed layer is a thin film PANI / HCl / ZnO.The test results obtained by the morphology of the fibers intersect to form a porous structure looks homogeneous ZnO particles, whereas to determine the value of conductivity using the LCR-Meter, the value of orders 10 -4 / m, which meets the conductivity value as a semiconductor material.