Tubular Lamps Research Articles

Photocatalytic NOx removal with TiO2-impregnated 3D-printed PET supports

In this work, we investigated the photocatalytic removal of NOx using 3D-printed supports. Monolithic supports with internal channels were fabricated by Fused Modelling Deposition (FDM) using PET as the filament feedstock. The printing parameters of the supports were optimized to maximize the exposure of the photocatalyst to UV light throughout the monolithic PET printed supports. The removal experiments were carried out in a continuous gas phase flow reactor, which was custom designed in-house incorporating a 3D printed PET support impregnated with TiO2 as photocatalyst. The impregnated and non-impregnated supports were characterized by diffuse reflectance spectrometry, SEM and AFM. The effect of several key-factors on the NOx removal capacity was investigated, including the type of PET filament (native recycled, BPET vs. glycol-modified, PETG), the type of TiO2 (P25 vs. Hombikat UV-100), the UV light source (LED vs. tubular lamps), and the number of deposited TiO2 layers. The highest NO and NOx removal were achieved by using PETG supports coated with a single layer of Hombikat UV-100 and irradiating the flat reactor from both sides using two sets of black light lamps. However, the highest selectivity toward nitrate formation was obtained when using P25 under the same experimental conditions. This work demonstrates that 3D printing is a reliable and powerful technique for fabricating photocatalytic reactive supports that can serve as a versatile platform for evaluating photocatalytic performance.

The effects of lamp types and surface reflectance combinations on the subjective perception of a simulated lit hospital ward environment

PurposeGood illumination creates an aesthetic environment that may positively influence patients’ well-being and provide comfort to the hospital staff. This study aims to focus on exploring the energy efficiency of lighting and subjective perception of the lit environment in a hospital ward to assess quality indicators of ambient lighting conditions.Design/methodology/approachThe existing conventional tubular fluorescent lamp–based lighting system in the surveyed patients’ ward was retrofitted with light-emitting diode (LED) luminaires to explore illumination and energy parameters. Thereafter, a software lighting model was created, simulated and analyzed. A Web-based survey with five bipolar adjective pairs in a semantic differential scale was conducted with 48 participants to record and analyze their subjective responses pertaining to the variations in lamp types and surface reflectance combinations.FindingsThe findings imply that the LED tubular lamp–based illumination was deemed more adequate compared to other lamp types and the effects of variations in room surface reflectance combinations on the participants’ responses were statistically significant at α = 0.05 level. The simulated horizontal work plane average illuminance level varied from 131 to 171 lx, mean room surface exitance (MRSE) levels remained between 30 and 90 lm/m2 and overall uniformity of illuminance remained between 0.5 and 0.7.Originality/valueIn a hospital ward illuminated by LED tubular lamps, variations in room surface reflectance combinations for a constant luminous flux package output from the lamps may affect the subjective perception of users and the correlation between horizontal work plane average illuminance and MRSE is found to be highly linear (coefficient of determination > 0.97).

A deep learning-based worker assistance system for error prevention: Case study in a real-world manual assembly

Modern assembly systems adapt to the requirements of customised and short-lived products. As assembly tasks become increasingly complex and change rapidly, the cognitive load on employees increases. This leads to the use of assistance systems for manual assembly to detect and avoid human errors and thus ensure consistent product quality. Most of these systems promise to improve the production environment but have hardly been studied quantitatively so far. Recent advances in deep learning-based computer vision have also not yet been fully exploited. This study aims to provide architectural, and implementational details of a state-of-the-art assembly assistance system based on an object detection model. The proposed architecture is intended to be representative of modern assistance systems. The error prevention potential is determined in a case study in which test subjects manually assemble a complex explosion-proof tubular lamp. The results show 51 % fewer assembly errors compared to a control group without assistance. Three of the four considered types of error classes have been reduced by at least 42 %. In particular, errors by omission are most likely to be prevented by the system. The reduction in the error rate is observed over the entire period of 30 consecutive product assemblies, comparing assisted and unassisted assembly. Furthermore, the recorded assembly data are found to be valuable regarding traceability and production improvement processes.

Re-layout of Temporary Storage Area for Toxic and Hazardous Waste using 5S (Seiri, Seiton, Seiso, Seiketsu, Sitsuke)

One of the industries that produces toxic and hazardous waste is rubber industry. This study was conducted in PT. Famili Raya. The problem was toxic and hazardous waste placed in an irregular placement and no follow the government regulations for storing and managing. This aims of this study were to redesign temporary storage area for hazardous waste based on 5S (Seiri, Seiton, Seiso, Seiketsu, Shitsuke) and the regulation, Minister of Environment and Forestry No. 12/2020. The object of this study was temporary storage area for toxic and hazardous waste in PT. Famili Raya. The data used were current condition, actual dimensions of temporary storage area, dimensions of waste, input and output data, and dimensions of a forklift. The results obtained were the proposed layout using the 5S approach could be used to redesign the storage layout in the temporary storage area. Space utility could be reduced by 32,67%. The decrease in space utility did not reduce the maximum storage capacity for used batteries, used tubular lamp, used oil waste, and turpentine oil waste.

Simulation Study on Factors to be Considered for Each Type of Indoor Luminaires and Light Sources when Converting to LEDs

As high-efficiency lighting has become mainstream, conversion of lighting equipment is under way, starting with government agencies. Existing fluorescent luminaires are being converted with LED luminaires. The main method used for conversion is to remove the fluorescent lamp (case 1) and replace it to a tubular LED lamp, and convert the luminaire itself with a LED panel luminaire (case 2). However, focusing only on energy efficiency, the existing luminous environment are not considered, such as illuminance, illuminance uniformity, and UGR. Therefore, the optical characteristics were measured using the actual luminaire used in the conversion. Simulations were performed comparing the luminous environment and power consumption before/after conversion. Case 1 had advantages in power consumption and UGR over case 2, and the illuminance was slightly reduced, but it met the criteria. These results confirmed that the conversion of lighting devices at least ensured the existing luminous environment.

Assessment of LED lamps components and materials for a recycling perspective

LED lamps have already conquered the market of general lighting. This new product will generate a substantial flow of e-waste requiring studies for the correct management, especially concerning recycling alternatives. This study proposes a material characterization of all the tubular and bulb LED lamp components (carcass, LEDs, printed circuit board and LED module). After manual disassembling, polymers were characterized by infrared spectroscopy (FTIR), and the metals by X-ray fluorescence (XRF) and acid leaching followed by ICP-OES analysis.By the novelty of separating and characterizing the LED lamp’s components, a process which has not yet been studied, the results allow for a better interpretation of the different materials distribution within the lamps which is essential to improve the efficiency of a recycling route. To exemplify, the element gallium, which has a recycling appeal from the LEDs, is present in a larger quantity in the printed circuit boards. The study also provides an analysis of the materials recycling rates and economic values, and the comparison with the concentration of natural ores. Thus, it was possible to discuss about target components and materials and the recycling alternatives for each component. LED lamps contain interesting materials, with even higher concentrations than natural ores, such as gold, silver, copper, aluminum, tin and gallium. If recycled, tubular lamps and bulb lamps would have the economic recovery of USD 2405.99 and USD 2595.02 per ton, respectively. The gold was found to be the most valuable material, and the LEDs the most valuable component of the LED lamps.

Numerical simulation and LEDs adaptation for grow lamp

Solid−state lighting technology based on LEDs offers ample opportunities in plant lighting. This article presents a prototype of a solid−state lamp based on InGaN LEDs with radiation peaks of 440, 460, 530 and AlInGaP with radiation peaks at 590, 630 and 660 nm, equipped with a source of stabilized current and an optimized radiator. The emission spectrum of the LED illuminator is the result of numerical simulation using an experimentally obtained absorption spectrum of a leaf of a plant. The effect of using LEDs was compared to the effect of a sodium tubular lamp. Evaluation of the results of biometric measurements that were made throughout the experiment showed the possibility of the effect of the spectrum of the proposed LED illuminator on plant growth.

Linear electro-optical effect in silica fibers poled with ultraviolet lamp.

A second-order nonlinearity was induced in silica fibers poled by exposure to ultraviolet (UV) radiation and simultaneous high voltage applied to internal electrodes. The UV light source was a tubular lamp with spectral peak at 254 nm. The highest second-order nonlinear coefficient measured through the linear electro-optic effect was 0.062 pm/V. The erasure of the recorded voltage with UV excitation was studied, and the stability of the poled fiber at a temperature exceeding ~400 K was investigated. By eliminating the use of a focused laser beam as excitation source, the technique enables poling many pieces of fiber in parallel.

Моделирование нестационарных процессов в импульсных трубчатых ксеноновых лампах в условиях возврата в плазму отраженного излучения

Моделирование нестационарных процессов в импульсных трубчатых ксеноновых лампах в условиях возврата в плазму отраженного излучения

Investigation of Spectral Characteristics of Pulsed Xenon Lamps for Combined Photochemical Degradation of Organometallic Compounds in Liquid Radioactive Waste

The paper considers the composition of liquid radioactive wastes from the nuclear plants. Using traditional ways to extract organometallic compounds formed, when using the deactivation solutions to clean the surfaces of nuclear plant rooms, are complicated. The paper studies the edge-cutting methods of solving this problem. Its proposal is to use a combined ultraviolet treatment for organometallic compounds degradation based on ethylenediaminetetraacetic acid (EDTA) via pulsed xenon lamps. A potential use of the tubular and spherical geometry lamps is examined and advantages, disadvantages and features of these lamps are described. Instead of the pure EDTA the experiments used its disodium salt ( Na 2 -EDTA). The hydrogen peroxide was used as an extra oxidizer. Absorption spectrums of solutions with various Na 2 -EDTA - hydrogen peroxide ratio were measured. It is found that the absorbance curve maximum is in the shortwave spectrum region (λ < 210 nm). The use of amalgam lamps of monochromatic radiation at wavelength λ = 254 nm will result only in formation of hydroxyl radicals but direct destruction processes of EDTA molecules due to radiation will be rare, and this decreases efficiency of their use. The spectral radiation characteristics of various continuum spectrum pulsed xenon lamps was measured. The experimental data expressed in relative units were compared with the emission spectrum of an absolutely black body. The paper shows that in spherical lamps high brightness temperature can be reached. Thus, in spherical lamps it is possible to obtain a spectrum, which is in maximum correlation with the absorption spectrum of the solutions under study, thereby making them a prospective radiation source for photo-degradation of EDTA compounds. For drawing a final conclusion it is necessary to conduct researches in order to compare Na 2 -EDTA degradation via tubular and spherical xenon lamps.

A Simple Method for Evaluating the Performance of Louvered Fixtures Designed for Upper-Room Ultraviolet Germicidal Irradiation

ABSTRACTThe primary objective of the present work was to develop and validate a simple method for measuring the ultraviolet (UV) emission rate of louvered UV fixtures designed for upper-room ultraviolet germicidal irradiation (UVGI). A secondary objective was to compare the emission rates and energy usage of a few commercially available fixtures and explain the reasons for the differences observed. The ultraviolet emission rate of fixtures designed for upper-room UVGI is clearly an important metric for specifying the UV dosing requirements for a particular application—that is, determining how many UV fixtures should be installed in a given room. UV emission rate is also important for evaluating how efficiently the fixture utilizes the required electrical power input. The ratio of the UV emission rate to the electrical input is a useful parameter for ranking or improving fixtures. In this article, we describe “UV sensor traverse” and its validation. UV sensor traverse is a simple method for measuring UV emission rate by traversing the louvered face of a fixture with a UV sensor. Using this method, we show that a commercially available fixture with a cylindrical parabolic reflector with a tubular lamp has about 84% of the UV radiation exiting the fixture emitted from the back of the lamp, compared to only 21% for a fixture with a flat reflector and compact lamps. The energy-use efficiency of the former fixture is about five times greater than that of the latter fixture. In the fixture with the parabolic reflector, UV rays are redirected by the reflector so that they tend to be parallel to the louvers, allowing significantly more of the UV radiation emitted from the back of the lamp to exit the fixture than a fixture with a flat reflector, which simply alters the direction of the UV rays. To conserve energy and minimize the number of louvered UV fixtures required, well-designed parabolic reflectors are essential.

Optimization of horizontal photocatalytic reactor for decolorization of methylene blue in water

The prototype photocatalytic reactor was designed and then constructed in a horizontal scheme for testing the decolorization of methylene blue (MB) as a toxic organic model by UVA irradiation. The optimization of the photocatalytic reactor with a recycling system using TiO2 nanoparticles (P25) as photocatalysts was investigated in this work. The efficiencies on MB photocatalytic decolorization of three geometric photocollectors in the reactor: (i) parabolic through collector (PTC), (ii) compound parabolic collector (CPC), and (iii) flat-plate collector (FPC), including the presence and the absence of parabolic reflector cover the UVA tubular lamp as an artificial light source were compared. Excepting only the CPC, the experimental results indicate that the orientation of light rays using the reflector as a primary and the collector as a secondary, can improve on the photocatalytic efficiency of MB decolorization. In our case, the PTC with the presence of the reflector shows higher performance on the MB decolorization than the CPC with the absence of the reflector and the FPC with the presence of the reflector. The photocatalytic reaction over MB decolorization can be explained under pseudo-first-order kinetics model. For our study, the optimums of MB suspension flow rate and TiO2 catalyst concentration were found toward 345 mL/min and 1.0 g/L, respectively.

Eliminating the Arcing Phenomenon in Field Emission Lighting Based on the Impulse-Power Technique

An impulse-power generator, which encompasses low-cost and simple configuration, operated in discontinuous conduction mode for driving a tubular field emission lamp (TFEL) is proposed. The proposed system based on flyback topology can provide impulse-power driving to eliminate arcing phenomenon caused by traditional dc voltage driving. Therefore, both the lighting performance and lamp lifespan are improved. This paper also presents a simple feedback mechanism to capture the peak value of the impulse lamp current for stabilizing lamp luminance. Next, an equivalent model of the TFEL is constructed to exhibit its capacitive characteristics. Furthermore, the circuit configuration and mathematical models of each operation mode in a switching cycle are also derived, and detailed design considerations are presented. All the experimental results agree with the computer simulations to verify the validity of the theoretical predictions.

Pulse current generator for driving tubular field emission lamp based on DCM flyback converter

This paper proposes a pulse current generator operated in discontinuous conduction mode for driving a tubular field emission lamp (TFEL). The proposed system based on flyback topology can provide pulse power driving to eliminate the temperature rise and arcing phenomenon caused by the traditional constant voltage driving. Therefore, both the lighting efficiency and lamp lifespan are improved. In this paper, an equivalent model of the TFEL is constructed to exhibit its capacitive characteristics. Moreover, the circuit configuration and each operation mode in a switching cycle are also described. And then a complete design considerations and mathematical model are discussed in detail. All the experimental results agree with the computer simulations to verify the theoretical predictions. Copyright © 2011 John Wiley & Sons, Ltd.

Longitudinal and transverse discharges with mercury-rare and xenon gases

The properties of longitudinal and transverse discharges are investigated with the use of external electrode tubular lamps, with respect to the characteristics of current and voltage, luminance and spectral radiation. With the mercury-rare gases, a high luminance of over 10 000 cd m−2 is readily obtained in the longitudinal discharge with a long positive column where the spectral radiations from Hg are dominant. However, the luminance is extremely low, a few hundred cd m−2, in the transverse discharge with a short gap where all kinds of atom species are ionized and the intensity of the spectral lines from Ne and Ar is rather high. With pure Xe and a mixture of Xe, the transverse discharge is superior to the longitudinal discharge in that the breakdown voltage is low and the luminance for a high pressure above 200 Torr is relatively high.

Photocatalytic Reactor Employing Titanium Dioxide: From a Theoretical Model to Realistic Experimental Results

The performance of a reacting system for degradation of trichloroethylene (TCE) in a pilot-size annular photocatalytic reactor having a tubular lamp located at its centerline was studied. The reactor operation was carried out with commercial catalytic particles of titanium dioxide (Aldrich) in a water suspension. The description of the reactor performance was made by employing a kinetic model developed in a laboratory reactor of different size and configuration, irradiated with similar lamps of lower output power. The annular reactor was operated in the continuous mode but inside the loop of a recirculation system.The performance of the annular reactor was modeled by assuming three different behaviors: (i) a well-stirred tank reactor, (ii) a pseudo-steady-state laminar flow reactor in a batch recycle, and (iii) a transient-state laminar flow reactor in a recycle. Case iii produced the best representation of the experimental data. Along with the experimental validation of the developed theoretical models, three practical features were unveiled that had to be taken into account in any subsequent design: (a) an important change in the pH, from 6.5 to 3.5, along the reaction time; (b) a significant titanium dioxide deposition on the reactor walls; and (c) an appreciable catalyst agglomeration produced by the recirculation system and magnified by the change in pH. Only after the first 120 min of reaction time, the reactor conditions became almost stabilized; thus, the observed transformations had to be incorporated into the modeling.

Performance of Ultraviolet Germicidal Irradiation Lamps and Luminaires in Long-Term Service

Seven years of experience operating upper-room ultraviolet irradiation systems (UVGI) in 14 homeless shelters in six cities has taught the Tuberculosis Ultraviolet Shelter Study (TUSS) many valuable lessons about maintaining uninterrupted UV services and acceptable intervals between UV lamp changes and cleaning activities. One year (9,000 hours) of continuous illumination resulted in a reduction in UVC output of the two types of low pressure mercury lamps by 17 percent for the quartz, instant start tubular lamp and 25 percent for the preheat compact lamps. The reduction over time was due to metal accumulations on the inside of the glass plus increasing opaqueness (solarization) due to UV irradiation. Cleaning frequency was found to be highly site-specific. Lamp failure was infrequent and within the manufacturers' stated life period.

Light‐emitting diodes for the illumination of algae in ecotoxicity testing

Ecotoxic effects of chemicals, preparations, and environmental samples are routinely quantified in standardized algae growth inhibition tests using microalgae like Desmodesmus subspicatus. The intention of this investigation was to prove the suitability of light-emitting diodes (LEDs) as an alternative to tubular discharge lamps in algae growth inhibition tests. This was approached by demonstrating that growth of algae was similar with both illuminating devices. Growth factors of growth controls were determined using LEDs. Growth curves of different light intensities of LEDs were compared with those of tubular discharge lamps. By testing certain chemicals with both illumination methods comparable results for E(r)C50 values were obtained. It could be shown that small-scale construction of incubators using LEDs is possible and could be advantageous, especially for the illumination of algae in 96-well microplate growth inhibition assays.

Influence of the UV radiation wavelength on the curing of oligourethaneacrylate compositions for protective coatings of optical fibers

The curing kinetics of films produced from compositions based on UV-curable oligourethaneacrylates is investigated using, as a source of radiation, an individual spectral line separated by a monochromator from the radiation of a DRT-400 mercury tubular lamp. It has been established that in the region of spectral sensitivity of the composition, the curing time of the film is inversely proportional to the intensity of volumetric absorption of the radiation-source photons by the initiator at the lower surface of the film under study. Individual contributions of some of the lines to the process of composition curing by using the integral spectrum of the radiation source have been evaluated. The spectral-kinetic results obtained were confirmed when using the compositions under study as protective coatings of optical quartz fibers.

Photocatalytic reactors: Reaction kinetics in a flat plate solar simulator

The kinetics of the photocatalytic decomposition of low concentrations of trichloroethylene (TCE) in water was modeled and the reaction parameters have been evaluated for different catalyst loadings. The employed reactor is a flat plate configuration irradiated by tubular lamps that have emission in the 300–400 nm wavelength range. The mass conservation model is two-dimensional while the developed radiation model is two-dimensional in space and two directional in radiation propagation. The performance of the photoreactor with this reaction can be properly represented employing only two lumped kinetic constants that can be derived from a 12 steps, complete reaction sequence. The deduced kinetic model has explicit functional dependencies for the local volumetric rate of photon absorption (LVRPA) and the effect of the catalyst concentration: r TCE, het ( x ̄ ,t)a v =−S g C m, cat α ∫ λ e λ a ( x ̄ ,t,C m,cat ) d λ [α 3C TCE /(1+α 3C TCE )] . Values of the kinetic constants are: α=1.94×10 −9 mol g 1/2 cm −2 s −1/2 einstein −1/2 and α 3=5.52×10 6 cm 3 mol −1. As derived from the reaction sequence and validated with experiments, it was observed that the reaction rate is proportional to the square root of the LVRPA. The dependence on the catalyst loading, well described by the model, is more complex due to its characteristic effect on the light distribution inside the reaction space.