Fluorescent Light Tubes Research Articles

A functional decision support system for management of Graphiola leaf spot (Graphiola phoenicis) disease during hardening of date palm tissue cultured plants in a greenhouse

A functional decision support system (DSS) was developed through optimising values of parameters favour faster growth and development of tissue cultured plantlets of date palm and suppression of disease infection. The programming of control devices was further managed based on the ambient environmental conditions, which required variable simulation periods and a plan for controlling of all systems for maintaining the greenhouse environment. During the process of plant hardening, the plants were infected by Graphiola leaf spot (Graphiola phoenicis). The moderate temperature, and high humidity inside the greenhouse, accompanied by short days and frequent occurrence of fog during winter months, favoured the development of smut infection. It is required to manage an extended photoperiod for 16 hours with 15000 lux light intensity provided by white fluorescent tube lights and incandescent bulbs inside the greenhouse. The integrated practices of enhanced photoperiod and light intensity under the greenhouse in combination with fungicides application to plants were found very effective in suppressing the intensity of the disease and its adverse effects on the plants. Using this decision support system (DSS), the tissue cultured date palm plants cv. Barhee has been successfully hardened and managed disease and transplanted in the field for further studying establishment, survival, plant growth and fruiting-related parameters.

Evaluation of the solar-powered Silver Bullet 2.1 (Lumin 8) light trap for sampling malaria vectors in western Kenya

BackgroundCenters for Disease Control and Prevention (CDC) light traps are widely used for sampling mosquitoes. However, this trap, manufactured in the USA, poses challenges for use in sub-Saharan Africa due to procurement costs and shipping time. Traps that are equally efficient than the CDC light trap, but which are amenable for use in remote African settings and made in Africa, are desirable to improve local vector surveillance. This study evaluated a novel solar-powered light trap made in South Africa (Silver Bullet trap; SB), for its efficiency in malaria vector sampling in western Kenya.MethodsLarge cage (173.7 m3) experiments and field evaluations were conducted to compare the CDC-incandescent light trap (CDC-iLT), CDC-UV fluorescent tube light trap (CDC-UV), SB with white diodes (SB-White) and SB with UV diodes (SB-UV) for sampling Anopheles mosquitoes. Field assessments were done indoors and outdoors following a Latin square design. The wavelengths and absolute spectral irradiance of traps were compared using spectrometry.ResultsThe odds of catching a released Anopheles in the large cage experiments with the SB-UV under ambient conditions in the presence of a CDC-iLT in the same system was three times higher than what would have been expected when the two traps were equally attractive (odds ratio (OR) 3.2, 95% confidence interval CI 2.8–3.7, P < 0.01)). However, when the white light diode was used in the SB trap, it could not compete with the CDC-iLT (OR 0.56, 95% CI 0.48–0.66, p < 0.01) when the two traps were provided as choices in a closed system. In the field, the CDC and Silver Bullet traps were equally effective in mosquito sampling. Irrespective of manufacturer, traps emitting UV light performed better than white or incandescent light for indoor sampling, collecting two times more Anopheles funestus sensu lato (s.l.) (RR 2.5; 95% CI 1.7–3.8) and Anopheles gambiae s.l. (RR 2.5; 95% 1.7–3.6). Outdoor collections were lower than indoor collections and similar for all light sources and traps.ConclusionsThe solar-powered SB trap compared well with the CDC trap in the field and presents a promising new surveillance device especially when charging on mains electricity is challenging in remote settings.

Upcycling of fluorescent light tube glass via kiln-casting using its properties

Upcycling of fluorescent light tube glass via kiln-casting using its properties

Comparison of processing routes for recovery of rare earth elements from discarded fluorescent lamp phosphors

This study investigates two phosphor samples with three processing routes to extract rare earth elements (REE). Acid leaching in 2 M HCl, 80 °C, 1 h yielded higher REE extraction in the compact fluorescent lamp (CFL) feed (82% Eu), with varying rare earth (RE) purity (77–97%) compared to fluorescent tubelight (TL) feed (69% Eu, 98–95% purity). Mechanical activation (MA) of 30 and 60 min caused partial dissociation of the LAP (LaPO4:Ce3+Tb3+) phase and yielded 34% Ce, 36% Tb, and 40% La. Transmission electron microscopy results revealed the formation of polycrystalline sites, which improved RE recovery. Alkali baking showed better REE extraction for both phosphors. 86.5% Y, 69% Eu was selectively extracted in feed acid leaching, and 100% La, 60% Tb, 20.6% Eu after alkali baking with 97% purity and CeO2 in the leach residue. The acid baking route was preferred for CFL phosphor with 91% REE (43 % Tb) extraction and 98% purity. TL phosphor was better for Tb extraction. The alkali baking of TL feed and acid baking of CFL feed yields 37.7% and ∼30% rare earth oxides, respectively.

Stability Analysis of PFC Converters Under Different Source Impedances and Its Consequences on Zero-Crossing Distortion

In the presence of multiple power converters in a power system the total current may exhibit zero-crossing distortion in the form of recurrent damped oscillations with high magnitude. These oscillations are synchronized with the power system frequency. This paper presents a comprehensive analysis of the input current of single-phase ac-dc converters fitted with power factor correction (PFC) controllers. Emphasis is given on the impacts of the source impedance, and on how the number of converters connected to a common coupling point (PCC) impacts the PFC controller’s performance. A system model is developed followed by simulation and measurements in a real installation with electronic ballasts used to drive fluorescent lighting tubes. Results show that the recurrent damped oscillations originating from PFC controllers are close to the harmonic range and with a very low level of cancellation between devices. The magnitude therefore increases proportionally with the number of devices. As the source impedance increases, instability may occur. Possible explanations for these observations are discussed.

A modeling study of the impact of photolysis on indoor air quality

The importance of photolysis as an initiator of air chemistry outdoors is widely recognized, but its role in chemical processing indoors is often ignored. This paper uses recent experimental data to modify a detailed chemical model, using it to investigate the impacts of glass type, artificial indoor lighting, cloudiness, time of year and latitude on indoor photolysis rates and hence indoor air chemistry. Switching from an LED to an uncovered fluorescent tube light increased predicted indoor hydroxyl radical concentrations by ~13%. However, moving from glass that transmitted outdoor light at wavelengths above 380 nm to one that transmitted sunlight above 315 nm led to an increase in predicted hydroxyl radicals of more than 400%. For our studied species, including ozone, nitrogen oxides, nitrous acid, formaldehyde, and hydroxyl radicals, the latter were most sensitive to changes in indoor photolysis rates. Concentrations of nitrogen dioxide and formaldehyde were largely invariant, with exchange with outdoors and internal deposition controlling their indoor concentrations. Modern lights such as LEDs, together with low transmission glasses, will likely reduce the effects of photolysis indoors and the production of potentially harmful species. Research is needed on the health effects of different indoor air mixtures to confirm this conclusion.

Lighting - the way to reducing electrical energy demand in university buildings in Bangladesh

Lighting is one of the dominant electricity demand factors in the building energy sector and has huge potential for demand reduction. However, concerning the efficacy of energy consumption, this potential energy-saving option entails further investigations, particularly for developing countries. This study addresses the issues of an efficient lighting system design for educational institutions with particular attention to classroom and laboratory lighting systems for a university in Bangladesh as a case study. Measurements show that during the daytime, under clear and average sky conditions both rooms received sufficient natural light (&gt;300 lx) for educational activities, whereas under an overcast sky, only 50% space receives sufficient natural light. At night, the installed fluorescent tube lights illuminance level was found insufficient (&lt;300 lx) for educational activities. The inefficient lighting system design was found to be the main reason for this illuminance level. Simulation results reveal that light emitting diode (LED) tube lights with a maintenance factor of 0.8 could save 10,080-15,120 kWh, 91,929-137,894 BDT (1USD=84BDT), and 6,753-10,130 kgCO2-eq, energy, cost, and, greenhouse gas emissions respectively per year for the classrooms.

Evaluation of light emitting diode suction traps for the collection of livestock-associated Culicoides species in South Africa.

Risk analysis of pathogens transmitted by Culicoides (Diptera; Ceratopogonidae) depends on the ability to detect all potential vectors attacking livestock in an area. Onderstepoort 220-V ultraviolet (UV) down-draught light traps are considered the gold standard for this purpose. To improve the flexibility of this trap in the field, in the absence of 220-V power, the possibility of using low-energy light emitting diodes (LEDs) was assessed. The efficiency of a standard 220-V Onderstepoort trap (30 cm 8 W fluorescent UV light tube) was compared to that of 220-V Onderstepoort traps fitted with either two, four or eight individual white LEDs. The Onderstepoort 220-V trap was also compared to a 12-V Onderstepoort trap fitted with an 8 W fluorescent UV light tube, a 12-V Onderstepoort trap with 12 individual white LEDs and 12-V and 220-V Onderstepoort traps fitted with 12 individual UV LEDs. Higher numbers of Culicoides as well as species diversity were collected with a brighter light source. The use of UV LEDs in both the 12-V and 220-V combinations was comparable to the Onderstepoort 220-V light trap with ration to species diversity collected. The Onderstepoort 220-V light trap is recommended if large numbers of Culicoides need to be collected.

Eficiência energética em prédios de salas de aula naturalmente ventilados

Em 2014, foi publicada a Instrução Normativa 02/2014, do Ministério do Planejamento, Desenvolvimento e Gestão, obrigando os projetos de edificações e os retrofit de edificações públicas federais, com mais de quinhentos metros quadrados de área, a serem desenvolvidos buscando a Etiqueta Nacional de Conservação de Energia de Projeto nível A, de acordo com os Requisitos Técnicos de Qualidade para o Nível de Eficiência Energética de Edifícios Comerciais, de Serviços e Públicos (RTQ-C). O objetivo deste trabalho é verificar se projetos de prédios de salas de aula licitados por Instituições Federais de Ensino Superior (IFES) atendem à determinação da IN 02/2014 e, em caso negativo, como intervir para os projetos atingirem nível A. Foram analisados dez prédios naturalmente ventilados licitados por quatro IFES do Rio Grande do Sul, seguindo os procedimentos indicados no RTQ-C. Também foram realizadas simulações para verificar o consumo hipotético de energia se os edifícios fossem condicionados artificialmente. Como resultado, 60% dos projetos conseguiram alcançar o nível mais alto de eficiência energética, atendendo à Instrução Normativa. Também se verificou que, nos casos negativos, a substituição das lâmpadas tubulares fluorescentes por lâmpadas LED equivalentes e especificação de bacias sanitárias econômicas bastaria para os projetos obterem a classificação máxima.

Energy audit of a small commercial hospital building in Ranchi: A case study

Energy audit focuses on equipment energy consumption such as lighting, air-conditioning system, elevators, and other devices operating on electricity. Data of the energy consumption recorded are used to identify and rectify by presenting detailed energy audit. Temperature, humidity, and CO2 emission of the building should be measured to conduct the investigation on detail energy analysis. Building utilizes major energy usage accounting to more than 30% overall energy usage. The commissioning and audit process results in the low-energy consumption and low equipment’s cost resulting in higher investment returns. This paper presents a detailed energy audit through a case study on small commercial hospital building located in Ranchi. The pre audit phase suggests that ceiling fans and fluorescent tube lights consume more than 50% of the total energy in the hospital. The energy auditing of the building resulting in annual energy savings of 7697.32 KW i.e. 35 % annual energy saving if recommended suggestions are followed. The recommendation of low-energy consuming equipment’s have payback period less than 6 years leading to higher return rate.

The blue light dose from white light emitting diodes (LEDs) and other white light sources.

This study was carried out to determine if light emitting diodes (LEDs) represented a special case in exposing the retina to blue light, when compared with other methods of backlighting television and computer screens and with fluorescent tube lighting. The spectral distribution of light from computer and television screens (cathode ray tube, plasma screen, organic LEDs, and screens backlit by cold cathode tubes and/or LEDs), domestic type spotlights (LED and fluorescent tube) and objects in the outdoor sunlit environment were measured with a telespectroradiometer. The spectral data were analysed for the proportion of blue light and luminance. The results were also presented as time to reach the occupational safety limit, without regard to the normal 10000s time limit by which time there is no summation of exposure. The amount of blue light in a source is essentially independent of the technology of the light source, but closely related to the correlated colour temperature. Fluorescent lamps show essentially the same proportions of blue light and LEDs do not represent a special case, given the same correlated colour temperature. Blue-blocking lenses are no more needed with LED sources than with other screen illumination methods or with fluorescent lighting. There is no evidence base on which to recommend blue-blocking lenses for indoor applications.

Indoor light energy harvesting using infrared LED

ABSTRACT Wireless sensor networks are mostly used at remote locations. Batteries are used to power the wireless sensor networks. Replacing batteries at remote locations is a costly and cumbersome process. Therefore, energy harvesting is a viable solution to charge these rechargeable batteries. This paper describes the design and experimental evaluation of indoor light energy harvesting system using infrared LED array, which consists of IR transmitters and IR receivers in series and parallel combination. Using the proposed design a considerable amount of energy can be obtained from fluorescent lamps or tube lights, which can be used to charge super capacitors or batteries. A DC power of 462 μW has been generated using the proposed design. This system can be used in a wireless sensor network designed for automation of the light/fan in the rooms.

Aural Textiles: From listening to pattern making

Textile patterns, whether printed, knitted, woven or embroidered, tend to be inspired by and created in response to the visual environment. The soundscape is a significant component of the embodied multisensory landscape – from the buzz of fluorescent tube lights in an office to the intermittent roar of water flowing in a river; no space is ever silent (). Attunement to environmental soundscape provides inspiration in music, art and, in this case, the creation of textile patterns, challenging the visual bias of pattern creation. In this ongoing study, the audio sources from bird song to horses galloping are visualized into spectrograms forming contemporary landscape-inspired textile patterns. Spectrograms are a type of visualization of an audio spectrum where the intensity and multiple frequencies are displayed across time, rather than simply the pitch and amplitude of the sound source. These spectrograms are then transformed into textile patterns through the interaction between a maker's existing skill set and digital software. By sharing this process with a group of textile practitioners, this sound-to-visual approach forms the foundation of a co-created textile pattern design. In this way, the process of soundscape-inspired design challenges the visual bias of existing textile patterns, contributing to the sensory ethnography of the contemporary landscape. Here we explore key insights that emerged from the project – experimenting, collaborating and disrupting – through the imagery of process and pattern making, as well as, through the narratives and reflections of the practitioners, presenting a collective visual encounter. In the end, the project opens dialogues to collaboratively understand and relate to the local soundscape as a source of inspiration for pattern making, and begins to formalize a design narrative based on the non-visual environment.

Potential of reflected UV imaging technique for detection of defects on the surface area of mango.

Surface defects such as mechanical damage, black lesion, latex stains and shriveling of mango fruit are very common and responsible for lowering of market prices as well as postharvest losses. Current research, thus, focused on the study of reflected ultraviolet imaging (UV) technique, its potential of detecting defected mangoes and to develop a computer vision system which could find the reflected area on injured or defected mango's surface. The visual visualization of the bruised areas was noticed different when viewed under 15W fluorescent UV tube (100-400nm) light by UV camera. Hidden defects on fruit's surface detected just after the image acquisition by UV camera and brightness enhancement. Defected or injured surface of mangoes recognized easily by reflected UV imaging at 400nm band-pass filter. The seriousness of injuries which were not detected by RGB color camera, detected by reflected UV imaging technique exactly.

The Shape of Desire

The Shape of Desire

Electron-Affinity-Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye-Sensitized Solar Cells.

The synthesis, characterization, and photovoltaic performance of a series of indacenodithiophene (IDT)-based D-π-A organic dyes with varying electron-accepting units is presented. By control of the electron affinity, perfectly matching energy levels were achieved with a copper(I/II)-based redox electrolyte, reaching a high open-circuit voltage (>1.1 V) while harvesting a large fraction of solar photons at the same time. Besides achieving high power conversion efficiencies (PCEs) for dye-sensitized solar cells (DSCs), that is, 11.2 % under standard AM 1.5 G sunlight, and 28.4 % under a 1000 lux fluorescent light tube, this work provides a possible method for the design and fabrication of low-cost highly efficient DSCs.

Electron‐Affinity‐Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye‐Sensitized Solar Cells

AbstractThe synthesis, characterization, and photovoltaic performance of a series of indacenodithiophene (IDT)‐based D‐π‐A organic dyes with varying electron‐accepting units is presented. By control of the electron affinity, perfectly matching energy levels were achieved with a copper(I/II)‐based redox electrolyte, reaching a high open‐circuit voltage (&gt;1.1 V) while harvesting a large fraction of solar photons at the same time. Besides achieving high power conversion efficiencies (PCEs) for dye‐sensitized solar cells (DSCs), that is, 11.2 % under standard AM 1.5 G sunlight, and 28.4 % under a 1000 lux fluorescent light tube, this work provides a possible method for the design and fabrication of low‐cost highly efficient DSCs.

Direct Contact of Selective Charge Extraction Layers Enables High-Efficiency Molecular Photovoltaics

Summary Dye-sensitized solar cells (DSCs) are molecular photovoltaics that operate efficiently in direct solar and ambient light by employing dye-impregnated mesoscopic TiO 2 films with a redox electrolyte or hole conductor. Here, we report on an advanced DSC architecture, which achieves efficiencies of 13.1% under air mass 1.5 global, 100 mW cm −2 solar radiation, and power conversion efficiency of 32% under a standard Osram 930 Warm White fluorescent tube light at 1,000 lux intensity. The cell substantially benefits from the direct contact of the dye-impregnated TiO 2 film with the poly(3,4-ethylenedioxythiophene) (PEDOT) counter electrode acting as a hole collector. This reduces the diffusion path of redox mediator to merely the mesoporous TiO 2 film attenuating the Warburg resistance, which thereby boosts the photovoltaic performance. This architecture will not only accelerate the practical exploitation of DSCs, but also foster new types of light-harvesting devices using mesoscopic TiO 2 and PEDOT as electron and hole collection layers, respectively.

Analysis of Growth Parameters for Crop Vegetables under Broad and Narrow LED Spectra and Fluorescent Light Tubes at Different PPFs

Several physiological and yield parameters were evaluated in lettuce plants, cv. ‘Trocadero’, while growing at four different photosynthetic photon flux (PPF) (70, 120, 250 and 400 ± 10 µmol m-2 s-1), under four light spectra, white (W), red (R) and blue (B) Light-Emitting Diode (LED) lamps and cool white fluorescent tubes (FL). Yield parameters were also evaluated on spinach, turnip and radish, growing under identical light spectra but using a single PPF (340 ± 10 µmol m-2 s-1). Lettuce development was impaired at PPFs below 250 µmol m-2 s-1 for all tested spectra. At higher PPFs (250 and 400 ± 10 µmol m-2 s-1), for the two broad spectra tested (W LEDs and FL light), no significant differences were registered on all physiological and yield parameters evaluated. On all situations W LEDs performed, at least, as good as the FL light, indicating that actual W LEDs can efficiently replace traditional light sources, with all the inherent benefits, which include significant lower power consumption. For all species, narrow light spectra (R and B LEDs) proved not being able to provide normal plant development. Plants under R LEDs, although presenting, in some situations, a fresh weight higher than those achieved with the broad light spectra, always led to abnormal plant morphology, characterized by expanded petioles and leaf curling. B LEDs, in spite of promoting plant growth with normal morphology, frequently led to a lower number of leaves and consequently to a lower fresh weight.

Effect of Different Illumination Sources on Reading and Visual Performance.

Purpose:To investigate visual performance during reading under different illumination sources.Methods:This experimental quantitative study included 40 (20 females and 20 males) emmetropic participants with no history of ocular pathology. The participants were randomly assigned to read a near visual task under four different illuminations (400-lux constant): compact fluorescent light (CFL), tungsten light (TUNG), fluorescent tube light (FLUO), and light emitting diode (LED). Subsequently, we evaluated the participants’ experiences of eight symptoms of visual comfort.Results:The mean age of the participants was 19.86 ± 1.09 (range: 18–21) years. There was no statistically significant difference between the reading rates of males and females under the different illuminations (P = 0.99); however, the reading rate was fastest among males under CFL, and among females under FLUO. One way analysis of variance (ANOVA) revealed a strong significant difference (P = 0.001) between males and females (P = 0.002) regarding the visual performance and illuminations.Conclusion:This study demonstrates the influence of illumination on reading rate; there were no significant differences between males and females under different illuminations, however, males preferred CFL and females preferred FLUO for faster reading and visual comfort. Interestingly, neither preferred LED or TUNG. Although energy-efficient, visual performance under LED is poor; it is uncomfortable for prolonged reading and causes early symptoms of fatigue.