Lamp Intensity Research Articles

Decontamination Efficiency of a DBD Lamp Containing an UV-C Emitting Phosphor.

Among different physical and chemical agents, the UV radiation appears to be an important route for inactivation of resistant microorganisms. The present study introduces a new mercury-free Dielectric Barrier Discharge (DBD) flat lamp, where the biocide action comes from the UV emission produced by rare-earth phosphor obtained by spray pyrolysis, following plasma excitation. In this study, the emission intensity of the prototype lamp is tuned by controlling gas pressure and electrical power, 500 mbar and 15 W, corresponding to optimal conditions. In order to characterize the prototype lamp, the energetic output, temperature increase following lamp ignition and ozone production of the source were measured. The bactericidal experiments carried out showed excellent results for several gram-positive and gram-negative bacterial strains, thus demonstrating the high decontamination efficiency of the DBD flat lamp. Finally, the study of the external morphology of the microorganisms after the exposure to the UV emission suggested that other mechanisms than the bacterial DNA damage could be involved in the inactivation process.

Characteristics of a nanosecond-barrier-discharge-pumped multiwave UV – VUV lamp on a mixture of argon, krypton and vapours of freon

We present the results of investigation of the characteristics of a nanosecond-barrier-discharge-pumped multiwave lamp based on a gas mixture of , which emits in the spectral range of . The main emission bands in the lamp spectrum are near near and near . The lamp intensity with respect to pressure, working mixture composition and pump regime is optimised.

Application of Artificial Neural Networks for Prediction of Photocatalytic Reactor

In this paper, forecasting of kinetic constant and efficiency of photocatalytic process of TiO2 nano powder immobilized on light expanded clay aggregates (LECA) was investigated. Synthetic phenolic wastewater, which is toxic and not easily biodegradable, was selected as the pollutant. The efficiency of the process in various operation conditions, including initial phenol concentration, pH, TiO2 concentration, retention time, and UV lamp intensity, was then measured. The TiO2 nano powder was immobilized on LECA using slurry and sol-gel methods. Kinetics of photocatalytic reactions has been proposed to follow the Langmuir-Hinshelwood model in different initial phenol concentration and pH. Several steps of training and testing of the models were used to determine the appropriate architecture of the artificial neural network models (ANNs). The ANN-based models were found to provide an efficient and robust tool in predicting photocatalytic reactor efficiency and kinetic constant for treating phenolic compounds.

Investigation on Metal-Induced Crystallization of Amorphous Silicon Using Xenon Flash-Lamp

Flash-lamp annealing (FLA) is an alternative technique for crystallization of amorphous silicon which can be scaled to large substrates. A process using FLA may have significantly reduced process complexity and time; however published results that demonstrate potential for use in flat panel displays have been limited [1]. This work investigates FLA in combination with metal-induced crystallization (MIC). The FLA system used in this work is a NovaCentrix PulseForge 3300, which anneals the material using a series of short but intense bursts of broad spectrum light from xenon flash lamps. High peak power over microseconds time scale can provide control over the depth of heating to avoid damage when processing on substrates such as glass or plastic. Input factors to the FLA system included lamp intensity, pulse width, number of pulses and repetition rate. Since samples are not in thermal equilibrium during FLA, power/time/flash-count combinations that deliver the same energy produce very different results. Additional factors included use of an anti-reflective SiO2 layer, and substrate heating (steady-state). Performing FLA on samples with trace amounts of nickel has demonstrated effective crystallization with single-pulse exposures delivering energy of ~ 5 J/cm2. Experiments which investigate the influence of both MIC and FLA process parameters on the material properties and electrical characteristics of TFTs will be presented. [1] S. Saxena, D. C. Kim, J. H. Park, and J. Jang, "Polycrystalline silicon thin-film transistor using Xe flash-lamp annealing," IEEE Electron Device Letters, vol. 31, pp. 1242-1244, 2010

Enhanced photoelectrical conductivity of poly (3-hexylthiophene) by incorporation of ZnS nanoparticles

This paper reports an enhanced photoconduction behaviour of organic (poly 3-hexylthiophene)–inorganic (zinc sulphide) hybrid system. Poly (3-hexylthiophene) (P3HT) and ZnS nanoparticles have been synthesized by chemical route at 0°C and 80°C, respectively. The separately prepared organic–inorganic materials were blended in a nanohybrid system and coated over to ITO electrodes to forms different samples with different concentrations (5–15wt%) of ZnS nanoparticles. The UV–visible spectra of these hybrid materials show an increase in the FWHM with ZnS nanoparticles, attributing to the enhanced optical properties. The photoconduction behaviour of the prepared samples has been investigated through current–voltage (I–V) measurements carried out under dark and light with fixed intensity (∼4.0W/m2) of tungsten lamp. It is observed that photocurrent increases with ZnS concentration. Also, quenching has been observed for the samples having higher concentration of ZnS nanoparticles, in P3HT matrix. The temperature dependence of electrical current in dark and light shows that the decrease in the resistivity with the temperature is more pronounced in the presence of light, indicating a photon activated process.

CS Optical Pumping Magnetic Sensor Spectrum Lamp Drive Circuit Design Based on PI Feedback Controller

The optical source is one of the key components for the optical pump magnetic field sensor, its spectral width, stability and emission intensity directly related to the sensitivity of the sensor. The CS Spectral Lamp drive signal source was produced by crystal oscillator and amplified by the power controllable RF power amplifier. For achieving the aim of luminous intensity controllable and more stability, the reference controllable analog PI negative feedback control measures were used in the drive circuit. Contrast experimental result show that: the emission intensity of CS spectrum lamp is more stable and less affected by temperature if using the drive circuit which discussed in this paper.

Estimation of the melatonin suppression index through clear and yellow-tinted intraocular lenses.

To estimate the melatonin suppression index (MSI), which may reflect the nonvisual photoreception function, through commercially available foldable, clear and yellow-tinted intraocular lenses (IOLs). The MSIs for 13 IOL models (6 clear IOLs, 7 yellow-tinted IOLs) with three lens powers were calculated based on previously reported data about the melatonin suppression spectrum, spectral intensity of a 20-W white fluorescent lamp and spectral transmission of IOLs in wavelengths from 300 to 800nm. The models tested were the SA60AT and SN60AT (Alcon Japan); the VA-60BBR, YA-60BBR, and NM-1 (Hoya); the AU6K and AN6K (Kowa); the N4-18B and N4-18YG (Nidek); the X-60 and NX-60 (Santen); and the KS-3Ai and KS-AiN (Staar Japan). The MSIs of the clear IOLs ranged from 1.12 to 1.18mWcm(-2)sr(-1) and those of the yellow-tinted IOLs from 0.74 to 1.01mWcm(-2)sr(-1). All yellow-tinted IOLs had significantly lower MSIs (P<0.0001-0.0021) than the clear IOLs; the %MSI cutoff values for yellow-tinted IOLs compared to the clear IOLs were 11.4-36.2%. The MSIs of the six clear IOLs did not differ based on lens powers (P=0.2159-0.6144). Except for one IOL model, all yellow-tinted IOLs had a lower MSI with higher lens powers compared to those with lower lens powers (P<0.0001-0.0055). Compared to phakic eyes (MSI, 1.03mWcm(-2)sr(-1)), the MSIs of the clear IOLs were higher (%MSI cutoff, -14.6 to -8.4%), whereas those of the yellow-tinted IOLs were lower (2.6-28.1%). Compared to aphakic eyes (MSI, 1.21mWcm(-2)sr(-1)), the MSIs of the clear (2.1-7.4%) and yellow-tinted (16.7-38.6%) IOLs were lower. Yellow-tinted IOLs absorb more circadian rhythm-associated light than clear IOLs. The difference in the lens power is significantly related to the MSI value in some yellow-tinted IOLs. To correlate the current data with the clinical relevance of these findings, the percent loss of the MSI leading to a circadian rhythm disorder needs to be clarified.

Effects of processing variables on polypropylene degradation and long chain branching with UV irradiation

A technique has been developed to modify the melt properties of polypropylene (PP). Photoinitiators along with UV irradiation were employed to introduce long chain branching (LCB) and/or crosslinking (CL). Statistically designed experiments were carried out to study the effect of processing conditions, such as photoinitiator concentration, duration of irradiation, UV lamp intensity, cooling air pressure, and photoinitiator type, on rheological properties, molecular weight characteristics and branching level. Samples were evaluated through linear viscoelastic (LVE) measurements, extensional rheometry, gel content, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Results clearly indicated that PP can be successfully modified in order to enhance strain hardening behaviour without significant gel formation.

Crystallization of Amorphous Silicon and Dopant Activation using Xenon Flash-Lamp Annealing (FLA)

ABSTRACTFlash-lamp annealing (FLA) has been investigated for the crystallization of a 60 nm amorphous silicon (a-Si) layer deposited by PECVD on display glass. Input factors to the FLA system included lamp intensity and pulse duration. Conditions required for crystallization included use of a 100 nm SiO2capping layer, and substrate heating resulting in a surface temperature ∼ 460 °C. An irradiance threshold of ∼ 20 kW/cm2was established, with successful crystallization achieved at a radiant exposure of 5 J/cm2, as verified using variable angle spectroscopic ellipsometry (VASE) and Raman spectroscopy. Nickel-enhanced crystallization (NEC) using FLA was also investigated, with results suggesting an increase in crystalline volume. Different combinations of furnace annealing and FLA were studied for crystallization and activation of samples implanted with boron and phosphorus. Boron activation demonstrated a favorable response to FLA, achieving a resistivity ρ &lt; 0.01 Ω•cm. Phosphorus activation by FLA resulted in a resistivity ρ ∼ 0.03 Ω•cm.

On the Intensity Profile of Electric Lamps and Light Bulbs

We demonstrate that the time profile of the light intensity from domestic lighting sources exhibits simple yet interesting properties that foster lively student discussions. We monitor the light intensity of an industrial fluorescent lamp (also known as TL) and an incandescent bulb using a photodetector connected to an oscilloscope. The light intensity of these sources displays modulation at twice the ac power supply frequency. The familiarity of ac line power supply, commonplace light sources, and simplicity of the setup encourage student confidence, allowing them to think deeper and continually reassess their notions, and if managed can lead to a satisfactory explanation of the observations.

Temperature Dependence of Ozone Loss Rate

The effective lifetimes of ozone molecules in oxygen in a stainless steel cylindrical cell are obtained by monitoring the ozone losses by the HgI 253.7 nm photo-absorption method. To eliminate data biasing due to drifts of the low pressure mercury lamp intensity, a simple and compact version of the double beam setup is used. It is based on the usage of a reference channel with a separate light detector and calculated drift corrections. In this work results on the temperature dependence of the ozone effective lifetimes in the temperature range 20-80 °C for oxygen pressure values between 10 and 1000 Torr are reported.

Low temperature growth of SnO2 nanowires by electron beam evaporation and their application in UV light detection

For the first time, high quality tin oxide (SnO2) nanowires have been synthesized at a low substrate temperature of 450°C via vapor–liquid–solid mechanism using an electron beam evaporation technique. The grown nanowires have shown length of 2–4μm and diameter of 20–60nm. High resolution transmission electron microscope studies on the grown nanowires have shown the single crystalline nature of the SnO2 nanowires. We investigated the effect of growth temperature and oxygen partial pressure on SnO2 nanowires growth. Variation of substrate temperature at a constant oxygen partial pressure of 4×10−4mbar suggested that a temperature equal to or greater than 450°C was the best condition for phase pure SnO2 nanowires growth. The SnO2 nanowires grown on a SiO2 substrate were subjected to UV photo detection. The responsivity and quantum efficiency of SnO2 NWs photo detector (at 10V applied bias) was 12A/W and 45, respectively, for 12μW/cm2 UV lamp (330nm) intensity on the photo detector..

Improvement of a Measurement System for Surface Loss Rate of Ozone

Ozone molecules present in high-purity oxygen as a feed gas interact with surfaces and oxygen molecules in an enclosed container. Therefore, some of the ozone molecules are destroyed and the density of ozone decreases with time. An experimental system has been constructed to monitor the temporal decrease in ozone density in a container based on the HgI 254 nm photoabsorption method. Our investigation is focused on the dependence of the effective lifetime of ozone on the wall material at various gas pressures. During the experiments, distortion of the measured decay curves often caused by instabilities in the mercury lamp intensity. We thus attempted to build a simple setup that eliminates the effect of long-term intensity drift. This setup is based on light source intensity monitoring by a separate photodetector and data correction software. This article describes the setup of the experimental apparatus, the results including some preliminary experiments and the temporal variation of the surface loss rate of ozone by repeated measurement along with inspections of the wall surface by Auger electron spectroscopy.

Flow-through ionization chamber for measuring the radiation intensity of VUV sources

This paper describes a device for measuring the radiation intensity of sources of vacuum ultraviolet radiation, consisting of a flow-through ionization chamber that operates in the total-radiation-absorption regime at atmospheric pressure. Examples of the use of this chamber to measure the radiation intensity of sealed photoionization lamps are described. The main advantage of the device is that it does not require periodic calibration or complex metrological assurance.

Kinetics study of photocatalytic process for treatment of phenolic wastewater by TiO2 nano powder immobilized on concrete surfaces

In this study, kinetics of photocatalytic degradation of phenolic wastewater in immobilized photocatalytic reactor was investigated. Immobilization of titanium dioxide (TiO2) nano powders on concrete surfaces were accomplished with epoxy concrete sealer. Kinetics of photocatalytic reactions has been proposed to follow the Langmuir–Hinshelwood model in different initial phenol concentration, pH, and UV lamp intensity. First-order reaction kinetics with respect to the pollutant concentration was obtained for the reaction. Effect of UV lamp intensity showed that kinetic constants were proportional to the power of 0.73–1 of the photonic flow. In all cases kinetic constant increases as pH of the system reached up to 12 units. Several reaction intermediates were identified using the GC/Mass analysis. Products at the initial stage of the reaction were aromatic compounds, contained hydroquinone, benzoquinone, and catechol. These intermediates underwent further photocatalytic oxidation to aliphatic compounds and finally into CO2 and H2O after 4 h. Kinetic constants of intermediate compounds were determined using mathematical–chemical equations and nonlinear regression. Data showed that the differences between the mathematical model and Langmuir–Hinshelwood model for the kinetic constant was less than 5%.

Influence of temperature and UV intensity on photo-polymerization reaction studied by photo-DSC

Photo-DSC was used to investigate the cure kinetics of a photo-initiated resin. The exothermal photo-polymerization reactions were performed in isothermal mode. The irradiation of photo-initiated resin was studied under different conditions of temperature, UV lamp intensity, and reaction atmosphere (nitrogen and air). The results obtained by photo-DSC allowed us to determine kinetic data of the photo-polymerized reactions: the global activation energy and reaction enthalpy, and the conversion as a function of time and temperature. Modulated temperature DSC measurements were carried out to verify whether vitrification occurs during polymerization. The conversion at the top and bottom of irradiated samples was obtained by FT-IR spectroscopy before and after photo-polymerization. A non-homogenous photo-polymerization into the material was observed, probably because of the light absorptions effects within the uppermost layers.

Photo and Electrocatalytic Treatment of Textile Wastewater and Its Comparison

ABSTRACT: Electrochemical and photochemical techniques have been proved to be effective for the removal oforganic pollutants in textile wastewater. The present study deals with degradation of synthetic tex-tile effluents containing reactive dyes and assisting chemicals, using electro oxidation and photocatalytic treatment. The influence of various operating parameters such as dye concentration, cur-rent density, supporting electrolyte concentration and lamp intensity on TOC removal has beendetermined. From the present investigation it has been observed that nearly 70% of TOC removalhas been recorded for electrooxidation treatment with current density 5 mA/dm 2 , supporting elec-trolyte concentration of 3 g/L and in photocatalytic treatment with 250 V as optimum lamp intensitynearly 67% of TOC removal was observed. The result indicates that electro oxidation treatment ismore efficient than photocatalytic treatment for dye degradation.Keywords : TiO 2 /UV, Electro oxidation, Photocatalysis, Organic pollutant, Textile effluent

Luminous efficacy measurement of solid-state lamps

We present a system for luminous efficacy measurements of solid-state lamps (SSLs). It is based on a 1.65 m integrating sphere, originally designed for luminous flux measurements of dc-operated incandescent standard lamps. The sphere was slightly modified, and equipped with a programmable ac-power supply, as well as equipment for electrical power measurement of the lamps. The waveforms of both the electrical power and the luminous flux can be measured for analysing the quality of the electronics and the light produced by the SSLs. A goniospectrometer is used for angular characterization of the lamp intensity. Luminous efficacy test measurements were conducted for a group of 25 SSLs of different types. Special attention was paid to the spectral, spatial and self-absorption corrections to obtain low measurement uncertainty. The luminous efficacies were between 25 lm W−1 and 64 lm W−1, and the total harmonic distortions of the current waveforms were in the range of 30% to 280%. Depending on the lamp, the maximum deviation of the flux from its mean value was 0.06% to 105%. The relative expanded uncertainty obtainable for the luminous efficacy of a typical SSL with stable built-in electronics is 1.2% (k = 2).

원전 배관 감육 결함 검사를 위한 IR 열화상시험 조건 결정

This study conducted infrared (IR) thermography tests using pipe and plate specimens with artificial wall-thinning defects to find an optimal condition for IR thermography test on the wall-thinned nuclear piping components. In the experiment halogen lamp was used to heat the specimens. The distance between the specimen and the lamp and the intensity of halogen lamp were regarded as experimental parameter. When the distance was set to 1~2 m and the lamp intensity was above 60 % of full power, a single scanning of IR thermography detected all artificial wall-thinning defects, whose minimum dimension was $2{\Theta}

Visible light photocatalytic inactivation of Escherichia coli with combustion synthesized TiO2

The photocatalytic inactivation of Escherichia coli was studied with combustion synthesized TiO2 photocatalysts in the presence of visible light. A series of 400W lamps irradiating in the visible region of the solar spectrum was used. The effect of various parameters, such as catalyst loading, light intensity, presence of inorganic ions, addition of hydrogen peroxide and pH, on the photocatalytic inactivation of E. coli was investigated. Photolysis alone had a small effect on inactivation while the dark experiment resulted in no inactivation and Ag/TiO2 showed the maximum inactivation. At a catalyst loading of 0.25g/L, all the combustion synthesized catalysts showed better inactivation of E. coli compared to commercial Degussa P-25 (DP-25) TiO2 catalyst. An improved inactivation was observed with increasing lamp intensity and addition of H2O2. A negative effect on inactivation was observed by addition of inorganic ions such as HCO3−, SO42−, Cl−, NO3−, Na+, K+, and Ca2+. The photocatalytic inactivation of E. coli remained unaltered at different pH of the solution. The inactivation of E. coli was modeled with power law kinetics and was observed to follow first order kinetics.