scholarly journals Ultraviolet absorption of contaminants in water

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin Spangenberg ◽  
James I. Bryant ◽  
Sam J. Gibson ◽  
Philip J. Mousley ◽  
Yorck Ramachers ◽  
...  
Keyword(s):  
Uric Acid ◽  
Light Emitting Diode ◽  
Ultraviolet Absorption ◽  
The Other ◽  
Light Emitting ◽  
Potassium Hydrogen ◽  
Transmitted Signal ◽  
Deuterium Lamp ◽  
Combined Measurements ◽  
Absorption Measurements

AbstractContaminants in water were studied using ultraviolet absorption with light emitting diode and deuterium lamp sources, and a thresholding detector. The absorption spectra of potassium hydrogen pthalate, clothianidin, tryptophan, thiamethoxam, uric acid and metaldehyde were obtained in the range 200–360 nm. Only metaldehyde was not suitable for detection in this range. For the other contaminants, and mixtures of pairs of compounds, the transmitted signal could be approximately described with a simple spectral model of the source–absorption–detector system. Combined measurements at two wavelengths could allow relative concentrations in certain mixtures to be determined, and real-time absorption measurements were demonstrated in a flume.

scholarly journals Effect of ceramic thicknesses and opacities on water sorption and solubility of a light-curing resin cement by different units

2021 ◽  
Vol 20 ◽  
pp. e211656
Author(s):  
Gabriela Alves de Cerqueira ◽  
Lais Sampaio Souza ◽  
Rafael Soares Gomes ◽  
Giselle Maria Marchi ◽  
Paula Mathias
Keyword(s):  
Water Sorption ◽  
Light Emitting Diode ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
The Other ◽  
Experimental Conditions ◽  
Light Emitting ◽  
Light Curing

Aim: This study evaluated the water sorption and solubility of a light-cured resin cement, under four thicknesses and four opacities of a lithium disilicate ceramic, also considering three light-emitting diode (LED) units. Methods: A total of 288 specimens of a resin cement (AllCem Veneer Trans – FGM) were prepared, 96 samples were light-cured by each of the three light curing units (Valo – Ultradent / Radii-Cal – SDI / Bluephase II – Ivoclar Vivadent), divided into 16 experimental conditions, according to the opacities of the ceramic: High Opacity (HO), Medium Opacity (MO), Low Translucency (LT), High Translucency (HT), and thicknesses (0.3, 0.8, 1.5, and 2.0 mm) (n = 6). The specimens were weighed at three different times: Mass M1 (after making the specimens), M2 (after 7 days of storage in water), and M3 (after dissection cycle), for calculating water sorption and solubility. Results: The higher thickness of the ceramic (2.0 mm) significantly increased the values of water sorption (44.0± 4.0) and solubility (7.8±0.6), compared to lower thicknesses. Also, the ceramic of higher opacity (HO) generated the highest values of sorption and solubility when compared to the other opacities, regardless of the thickness tested (ANOVA-3 factors / Tukey’s test, α = 0.05). There was no influence of light curing units. Conclusion: Higher thicknesses and opacities of the ceramic increased the water sorption and solubility of the tested light-cured resin cement.

Absorption measurements in dense cesium vapor using a UV–violet light-emitting diode

2001 ◽  
Vol 72 (3) ◽  
pp. 337-341 ◽  
Author(s):  
T. Ban ◽  
H. Skenderović ◽  
S. Ter-Avetisyan ◽  
G. Pichler
Keyword(s):  
Light Emitting Diode ◽  
Cesium Vapor ◽  
Light Emitting ◽  
Violet Light ◽  
Absorption Measurements

scholarly journals Lifetime and optical analyses of LED lamps

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Emerson Roberto Santos ◽  
Hélio Akira Furuya ◽  
Elvo Calixto Burini Junior
Keyword(s):  
Light Emitting Diode ◽  
The Other ◽  
Optical Characteristics ◽  
Integrating Sphere ◽  
Initial Moment ◽  
Direct Relation ◽  
Light Emitting ◽  
Elapsed Time ◽  
The One

In this study, optical and lifetime analyses of commercial light-emitting diode (LED) lamps were carried out with the objective to better understand these characteristics. Lamps of different manufacturers and powers were used: Ourolux of 9 watts, Kian of 9 watts, Black+Decker of 9 watts, FLC of 8 watts, Galaxy of 7 watts and Brilia of 7 watts. These LED lamps remained on by 24 hours/day for 4,291.16 hours. Illuminance measurements were analyzed once a week by each lamp inside the integrating sphere with a sensor of lux meter coupled. Results showed decrease of illuminance by elapsed time, due to the degradation. Results of the illuminance obtained between the initial moment of the experiment and the final one were calculated, revealing degradation of 19% to Ourolux, 20% to FLC, 26% to Black+Decker, 28% to Kian, 29% to Galaxy and 33% to Brilia. This study suggests that the diffusers can have different transmittance values interfering on the illuminance, since the FLC LED lamp presented illuminance with highest values than the other LED lamps tested with similar electrical and optical characteristics. This experiment showed that the nominal power of the LED lamp has no direct relation to the illuminance and, comparing the lifetime, the LED lamp manufactured by Black+Decker was the only one to reach 5,521 hours, that is a lifetime much shorter than the one described at the packages (25,000 hours) for all LED lamps tested

scholarly journals PENGGUNAAN LIGHT EMITTING DIODE PADA LAMPU CELUP BAGAN (The Use of Light Emitting Diode on Sunked Lamps of Lift Net)

2016 ◽  
Vol 4 (2) ◽  
pp. 141
Author(s):  
Imanuel M. Thenu ◽  
Gondo Puspito ◽  
Sulaeman Martasuganda
Keyword(s):  
Key Words ◽  
Lower Cost ◽  
Light Emitting Diode ◽  
The Other ◽  
Fluorescent Lamp ◽  
Light Emitting ◽  
Led Light ◽  
Fluorescent Lamps ◽  
Energy Save

<p>ABSTRACT<br />Lift net fishermen usually use fluorescent lamp as attractor to lure fish. As price of fuel rise, fishermen are forced to find another option to change their attractor into some much lower cost and more energy-save lamp, or in other words, to change into LED lamp. This research are providing evidence that sunked LED lamps can be utilized as a helper tools, and also determined the best time for catching fish in the lift net. Two lift net used in this research, one of them used sunked LED lamps and the other used ordinary fluorescent lamps. Lift net are operated as long as 20 nights, with four catching times per night, between 18.00-21.00, 21.00-00.00, 00.00-03.00, and 03.00-06.00. Results showed that LED lamps give a better result with 11 organisms successfully catch (287,6 kg), compared to ordinary fluorescent lamps with only six organisms (238,3 kg). The best time for catching with LED lamps are between 18.00-21.00 (121 kg), while between 21.00-00.00 (67,4 kg), 00.00-03.00 (46,9 kg) and 03.00-06.00 (52,3 kg).<br />Key words: fluorescent lamp, lift net, light emitting diode, Palabuhanratu,sunked lights</p><p>-------</p><p><br />ABSTRAK<br />Nelayan bagan biasa menggunakan lampu fluorescent sebagai atraktor untuk memanggil ikan. Harga bahan bakar yang mahal menyebabkan nelayan harus beralih memakai jenis lampu lain yang hemat energi, seperti lampu LED (light emitting diode) Penelitian bertujuan untuk membuktikan bahwa lampu celup LED dapat digunakan sebagai alat bantu penangkapan ikan pada bagan dan menentukan waktu operasi penangkapan terbaik. Dua bagan digunakan dalam penelitian ini. Masing-masing menggunakan lampu celup LED dan lampu fluorescent. Bagan dioperasikan selama 20 malam. Dalam 1 malam dilakukan 4 kali penangkapan, yaitu antara jam 18.00-21.00, 21.00-00.00, 00.00-03.00 dan 03.00-06.00. Hasil penelitian menunjukkan bahwa penggunaan lampu celup LED pada bagan menghasilkan 11 jenis organisma tangkapan seberat 287,6 kg, atau lebih banyak dari lampu fluorescent sejumlah 6 organisma (238,3 kg). Adapun waktu penangkapan terbaik pada bagan yang menggunakan lampu LED adalah antara pukul 18.00-21.00 yang menghasilkan tangkapan seberat 121 kg, sedangkan 21.00-00.00 (67,4 kg), 00.00-03.00 (46,9 kg) dan 03.00-06.00 (52,3 kg).<br />Kata kunci: lampu fluorescent, bagan, light emitting diode, Palabuhanratu, lampu celup</p>

scholarly journals Redesigning Public Street Lighting Using Photometric Method

2021 ◽  
Vol 3 (1) ◽  
pp. 54-67
Author(s):  
Ade Abdullah ◽  
Muhammad Aziz ◽  
Muhammad Huda
Keyword(s):  
High Efficiency ◽  
Light Emitting Diode ◽  
The Other ◽  
Photometric Method ◽  
Main Road ◽  
Street Lighting ◽  
Light Emitting ◽  
Led Light ◽  
Significant Factors

Street lighting with LED (Light-Emitting Diode) technology is currently the main option of public lighting in almost every country. Even though LED technology is a less costly selection, there needs to be well planned in an attempt of acquiring high efficiency. The photometric approach was tested in this study in order to redesign the existing approach used in street lighting in Indonesia. The redesigning process was carried out using software namely DIALux on two different schemes; one with homogeneous luminaire and the other one with the non-homogeneous luminaire. The results of this study showed that the most significant factors in redesigning street lighting covered types of the lamp, pole distance, pole height, and proper lighting angles which could affect the illumination value on both the main road and the sidewalks. In addition, it has also been proven that a homogeneous approach using LED lamp lighting promoted uniformity as well as optimum illumination.

scholarly journals Improving hemoglobin estimation accuracy through standardizing of light-emitting diode power

2022 ◽  
Vol 12 (1) ◽  
pp. 219
Author(s):  
Caje Francis Pinto ◽  
Jivan Shrikrishna Parab ◽  
Marlon Darius Sequeira ◽  
Gourish Naik
Keyword(s):  
Light Emitting Diode ◽  
Estimation Accuracy ◽  
Coefficient Of Determination ◽  
Altman Analysis ◽  
Light Emitting ◽  
Non Invasive ◽  
Transmitted Signal ◽  
On Chip ◽  
Embedded Development ◽  
Good Agreement

Nowadays, hemoglobin monitoring is essential during surgeries, blood donations, and dialysis. Which are normally done using invasive methods. To monitor hemoglobin, a non-invasive hemoglobin meter was developed with five fixed light-emitting diode (LED) wavelengths at 670 nm, 770 nm, 810 nm, 850 nm, 950 nm and controlled using an Arduino Uno embedded development board. A photodetector with an on-chip trans-impedance amplifier was utilized to acquire the transmitted signal through the finger using the photoplethysmography (PPG) principle. Before the standardization of LED power, we had tested the designed system on fifteen subjects for the five wavelengths and estimated the hemoglobin with an accuracy of 96.51% and root mean square error (RMSE) of 0.57 gm/dL. To further improve the accuracy, the LED power was standardized and the PPG signal was reacquired on the same subjects. With this, the accuracy improved to 98.29% and also reduced the RMSE to 0.36 gm/dL. The designed system with LED power standardization showed a good agreement with pathology results with the coefficient of determination R<sup>2</sup>=0.981. Also, Bland–Altman analysis was used to evaluate the designed system and it showed good agreement between the two measurements.

Electrically Detected Magnetic Resonance of MEH-PPV diodes

2002 ◽  
Vol 725 ◽  
Author(s):  
George B. Silva ◽  
Lucas F. Santos ◽  
Roberto M. Faria ◽  
Carlos F. O. Graeff
Keyword(s):  
Magnetic Resonance ◽  
Light Emitting Diode ◽  
Forward Bias ◽  
The Other ◽  
Phenylene Vinylene ◽  
Second Line ◽  
G Factor ◽  
Light Emitting ◽  
Electrically Detected Magnetic Resonance ◽  
Gaussian Line

AbstractIn this work electrically detected magnetic resonance (EDMR) is used to study the electronic properties of poly(2-methoxy-5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene) (MEHPPV) diodes. Two kinds of MEH-PPV diodes were characterized. The first one was a bipolar light emitting diode whose structure was ITO/MEH-PPV/Al. In this diode the EDMR signal is composed of two lines, a line that can be fitted by a lorentzian with peak-to-peak linewidth of 5.0 ± 0.5 G and the other best fitted with gaussian line with a linewidth of 24 ± 1 G. The g factor of both components is 2.002 ± 0.001 and signals were only observed at forward bias. The second diode is a hole only device, with a structure ITO/MEH-PPV/Au, the EDMR signal in this case is dominated by a gaussian line with peak-to-peak linewidth of 5 ± 1 G and average g factor of 2.0014 ± 0.0002. In high forward bias (V > 30 volts at T = 130K) a second line could be observed with a linewidth of 10 ± 2 G and a g factor of 2.0012 ± 0.0004. The signal from both types of diodes is quenching, and tipically10-5 in amplitude. The EDMR signal is assigned to the spin-dependent fusion of two like-charged polarons. Our results indicate that the narrower component is coming from positive polarons while the broader to negative polarons.

scholarly journals Influence of photoinitiators and light sources on the degree of conversion of experimental resin cements.

2015 ◽  
Vol 18 (2) ◽  
pp. 65 ◽  
Author(s):  
Dario Raimundo Segreto ◽  
Fabiana Scarparo Naufel ◽  
William Cunha Brandt ◽  
Ricardo Danil Guiraldo ◽  
Lourenço Correr-Sobrinho ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
The Other ◽  
Light Sources ◽  
Spectroscopy Data ◽  
Resin Cements ◽  
Light Emitting ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Quartz Tungsten Halogen ◽  
Light Curing

<p><strong>Objective: </strong>The aim of this study was to evaluate the degree of conversion (DC) of seven experimental resin cements formulated with different photoinitiators when activated by two light-curing units (LCUs) through ceramic material. <strong>Material and Methods: </strong>Seven resin blends with different camphorquinone (CQ) and/or phenyl propanedione (PPD) rates were prepared: C5: 0.5% wt CQ; C8: 0.8% wt CQ; P5: 0.5% wt PPD; P8: 0.8% wt PPD; C1P4: 0.1% wt CQ and 0.4% wt PPD; C4P1: 0.4% wt CQ and 0.1% wt PPD; and C4P4: 0.4% wt CQ and 0.4% wt PPD. Each mixture was loaded with 65% wt of silanized filler particles. For photoactivation procedures, two LCUs were used: a quartz-tungsten-halogen (QTH) and a light emitting diode (LED). <strong>Results: </strong>Irradiance (mW/cm²) was calculated by the ratio of the output power by the area of the tip. DC was assessed by Fourier transformed infrared spectroscopy. Data were submitted to a two-way ANOVA and Tukey’s test (5%). DC values do not show significant differences for LCUs regardless of the photoinitiator type. The highest DC was found for experimental cement P8 and the lowest for C5. <strong>Conclusion:</strong> Intermediate DC values were found for the other cements. However, when QTH was used, P8 exhibited differences among C1P4, C4P1 and C5; whereas when LED was employed, P8 differed only for C4P1 and C5. Thus, PPD is a viable alternative for the manufacture of photoactivated cements, and the PPD/CQ association may also be viable since C4P4 was similar to P8.</p>

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