Light Tube Research Articles

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.

Flexural Ductility, Stiffness, and Toughness of New Voided Reinforced Concrete One-Way Slab Using Waste Plastic Bottles

The enhancement of concrete structures’ performance can easily be achieved. However, the main challenge is how to achieve this performance with respect to the economy and sustainability. The aim of this research is to examine the flexural strength, ductility, stiffness, and toughness of RC hollow one-way slabs that are voided by plastic bottles. A new technique of hollowing has been used in this work, where a steel mesh tube was prepared previously and filled manually with blank waste plastic bottles to form a light tube. This technique has some advantages including ease of installation and adequate bonding for the main steel reinforcements. Five RC one-way slabs were cast and tested in the lab to investigate some variables: the presence of hollow, the ratio of reinforcement, and slab thickness. Briefly, a new technique for voids enhances the flexural behavior with less concrete and weight. The ductility is increased by about 100% for the voided specimens for the same section’s thickness. Also, the rotation in supports had been reduced by about 30% when the thickness of voided slab was increased by about 15%.

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.

Experimental analysis of solar light pipes compared to direct and light-well daylight transmission methods for indoor spaces

Effective use of natural daylight in indoor spaces contributes to reduced energy consumption in electrical systems as well as improved occupants' visual comfort. Present experiments conduct image recording of three-floor level laboratory building models designed for solar daylight transmission through four different methods (simple window, light-well, and solar light pipes using two different flooring materials) under two incident light angles. The image-based analysis of the probability density functions associated with indoor illumination quantifies the qualitative visualizations of different daylight transmission techniques. It is found that using proper diffuser material for simple windows (direct method) may sacrifice nearly 2% of the light intensity, while significantly enhancing the distribution. In addition, the use of light pipes has provided the best distribution in the environment, which, in some cases, has improved the uniformity of light up to 15.7% compared to other methods. It is shown that the visual discomfort in direct and light-well methods due to the glare formation and indoor lighting non-uniformity under inclined incident light angles can be prevented by using light transmission tubes. At the same time, the use of light tubes at vertical angles improves intensity by up to 17.5% in addition to enhanced light distribution. Present findings based on statistical analysis clearly highlight the significance of quantifying the indoor ambient light distribution in addition to the overall intensity of light. From a practical point of view, the present study suggests that the proper implementation of light transmission tubes results in enhanced uniformity and visual comfort of indoor lighting due to glare reduction while providing sufficient light intensities comparable to other daylight transmission methods. For improved solar light pipe designs, it is also suggested to consider their efficiency dependence on the tube length as well as flooring materials.

Energy conservation for existing cooling and lighting loads

Energy consumption by cooling and lighting loads can be significantly reduced if real time information on the occupancy is applied in their control. To meet this goal smart cooling and lighting devices, which have built-in sensors and controllers and which make decisions on individual basis, are being developed. However, it appears that no attempt has yet been taken for auto-operation of the huge number of already existent so called “non smart” air conditioning (AC) and lighting loads considering the count and location of occupants. A good deal of research has been reported in literature on the line of deploying or improving occupant detecting sensors/cameras, processing the captured images and developing high performance occupant identification (only detection or detection and counting) algorithms. Those were focused on locating users and surveillance in a building. A comparison of those works reveals that cameras combined with faster RCNN (Region based Convolutional Neural Network) algorithm can best identify the occupants. However, none of the works reported any prototyping considering occupancy with or without other ambient conditions such as comfort level, temperature, humidity and luminance for cooling load set point temperature update and/or lighting load control. Furthermore, the way the existing cooling and lighting loads can be made amenable to occupancy sensitive operation for energy saving in a noninvasive way is not yet reported. The novelties and contributions of the present paper are on bridging the gaps viz. (i) prototyping using traditional cooling and lighting loads of any brand already existent in a space for achieving occupancy sensitive energy saving, (ii) developing a model using the total count of occupants in a space along with ambient temperature and humidity for update of the set point temperature of cooling loads such that energy will be saved while the occupants will feel comfort, (iii) generation of ON/OFF commands in real time for lighting loads considering zone wise location of occupants along with the difference between ambient and required luminance in a zone, (iv) auto transmission of the updated set point temperature and on/off commands wirelessly from a common GUI (Graphical User Interface) respectively to the cooling and lighting loads without requiring any “hand held remote”, and (v) noninvasive implementation i.e. no need to modify or open the existing cooling and lighting loads at all and fixing any gadget inside these. The method proposed has been implemented on 3 traditional split type AC units of different brands and 16 composite units of LED (Light Emitting Diode) tube lights already existent in a lab. Compared with the manual mode of control which is insensitive to occupancy, the proposed method shows an energy saving in the range of 12.7%–36.15% for cooling loads while in the range of 35%–87.5% for lighting loads as the occupancy varies from high to low. The main economic and commercial impact of the present research is avoiding or postponing the replacement of the huge number of existing cooling and lighting devices by their smart counterparts which is often unaffordable for the entities in many countries.

Eğitim Kurumu Binalarında Akıllı Aydınlatma Kontrol Sistemleriyle Gün Işığını Taşıyan Sistemlerin İncelenmesi

In this study, intelligent lighting control systems and daylight-carrying systems within the framework of methods that maximize daylight in educational institution buildings were examined. The purpose of these functions, known as intelligent lighting control systems, is to ensure the construction of sustainable educational institution buildings in the process that continues from the construction stage of educational institution buildings to the conduct of daily educational work. The main issues of attention in the buildings of this educational institution are intelligent lighting, high technology, daylight saving as much as possible, insulation and energy efficiency. In this way, intelligent lighting systems aim to minimize the installation load and usage times of energy-consuming systems of educational institution buildings and maximize the use of daylight without compromising the comfort conditions required by active users of buildings. Key Words: Heliostatic System, Lighting Guide, Lighting Tube, Fiber Optic

Application of bifunctional ionic liquids for extraction and separation of Eu3+ from chloride medium

The extraction of Eu3+ from chloride medium using bifunctional ionic liquid extractants (Bif-ILEs) tri-n-octylmethyl ammonium bis(2-ethyl hexyl) phosphate ([A336][D2EHP]) and trihexyltetradecyl phosphonium bis(2-ethylhexyl) phosphate ([P66614][D2EHP]) in kerosene was studied to develop environmentally friendly extraction process. The extraction behavior of Eu3+ was examined by varying key process parameters. The extraction behavior indicates that ammonium-based ionic liquid [A336][D2EHP] shows better extraction efficiency of Eu3+ than that of phosphonium-based ionic liquid [P66614][D2EHP]. Quantitative extraction of Eu3+ is obtained with 0.05 mol/L [A336][D2EHP], whereas, 0.1 mol/L of [P66614][D2EHP] is required to achieve the same extraction rate of Eu3+. The extraction process is endothermic with respect to [A336][D2EHP]. Stripping experiments indicate that 100% of Eu3+ can be back extracted from both the loaded ionic liquids using 20 vol.% HNO3. The highest separation factor (βY/Eu) of 653.59 is reported at pH of 3.2, and the separation factor of Eu3+ over La3+ is 30.6 at the same pH. From the leach liquors of waste tube light powder, 99.98% of Eu and 99.99% Y are recovered using 0.2 mol/L [A336][D2EHP] in 2-stage cross current extraction with aqueous to organcic ratio (O/A) of 1:1 and 1:2.

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.

Virgin and UV-weathered polyamide microplastics posed no effect on the survival and reproduction of Daphnia magna.

Although evidence suggests that microplastic (MP) particles pose a risk to organisms, the effects of virgin and weathered MP should be evaluated separately as their effects may be different. In this work, we provide new information on the toxic potential of virgin and UV-weathered polyamide, one of the commonly used plastics worldwide. Polyamide MP particles were subjected to UV-weathering in wet conditions over 26 days in a customized irradiation chamber equipped with UV-C light tubes (15 W each, max. wavelength 254 nm). The toxicity of virgin and UV-weathered polyamide MP (< 180 µm in one dimension, 100 and 300 mg L−1) was evaluated by studying Daphnia magna reproduction in natural lake water spiked with MP, following the 21-day OECD 211 test guideline. In parallel, a nonionic surfactant Tween 20 (7 mg L−1) was added to the test medium to improve the suspendability of the MP. The results of the tests showed no adverse effects of either virgin or UV-weathered polyamide MP on the reproduction of D. magna. In addition, presence of Tween 20 in the test medium had no effects on the test results. These results bring a new perspective on the potential long-term impact of polyamide particles on aquatic organisms, especially considering that the polyamide has received marginal attention in the ecotoxicological research. However, standard test endpoints (survival and reproduction) may still miss long-term adverse effects of insoluble e.g., plastic particles and additional studies may be necessary.

Evaluation of Baking Process for Rare-Earth Recovery from Discarded Tube Lights Phosphor

Evaluation of Baking Process for Rare-Earth Recovery from Discarded Tube Lights Phosphor

PSVII-1 Sample Handling and Vitamin Analysis

Abstract Vitamins are crucial for day-to-day function in the body. They are often collected in studies to ensure that the body is functioning normally, but the ways in which these samples are collected are inconsistent. Therefore, the objective of this study was to evaluate differences in sampling collection methods. A total of 4 blood tubes (2 serum and 2 plasma) were collected from 8 finishing pigs (n = 4 gilts and barrows). One blood tube of each type was either exposed to light or wrapped in foil before processing for analysis took place. Livers were taken from 6 gilts, sectioned, and those sections were either frozen immediately or placed at 1 of 3 temperatures (room temperature, 4oC, or -20oC) for 3, 6, or 12 hours before freezing to assess degradation of vitamins within the tissue. Blood was assessed for vitamins A, D, and E while liver was assessed for vitamins A and E with data analyzed by PROC GLIMMIX. There was a significant difference (P &amp;lt; 0.05) for the interaction of blood tube type and light exposure for vitamin D in the blood and a tendency (P &amp;lt; 0.10) for the interaction of blood tube type and light exposure for vitamin A in the blood. Furthermore, there were sex effects (P &amp;lt; 0.05) for vitamin D and (P &amp;lt; 0.10) vitamin A with barrows having higher vitamin statuses than gilts. There were no differences (P &amp;gt; 0.10) for the interaction of blood tube type and light exposure for vitamin E in the blood, or the amount of degradation of vitamins A and E in the liver. In conclusion, factors such as sex, blood tube type, and light, can influence vitamin concentration in biological samples.

Light Intensity Control Using Polaroids

Abstract: In today’s era of illuminating devices, there are a wide variety of devices available in aesthetics but the none with variable intensity of light. Using the basic principle of polarization of light using a Polaroid filter or polarizer, the designing of a light intensity control was done. The polarizing angle of the filter decides the intensity of the light that would pass through the filters. According to the principle of propagation of light, the electric and magnetic vibrations of a light wave occur perpendicularly to each other. A light wave that is vibrating in more than one plane is known as unpolarized light. The light emitted by the sun, by a lamp or a tube light are all unpolarized light sources. The other kind of wave is a polarized wave. A Plane polarized light vibrates on only one plane. The process of transforming unpolarized light into the polarized light is known as polarization. Using the same principle and with the use of a LDR (light dependent resister) as a sensor to sense the intensity of the surrounding light and then rotate the polaroid filter sheets accordingly using a stepper motor for the required change in intensity. The sensing and sending of feedback and subsequent rotation of the Polaroid filter sheets would be automated by ATMEGA32 microcontroller and L293D. Keywords: Polaroids, LDR, Light Variation, ATMEGA32, L293D

A comparative analysis for impact of distributed generations with electric vehicles planning

In the approaching years, the utilization of Distributed Generations (DGs) with Electric Vehicles (EVs) will accelerate. Future issues will be exacerbated by the relationship between the distribution system of DGs solely, DGs with Fuel Cell Electric Vehicle (FCEV), and DGs with Extended Plug-in Hybrid Electric Vehicles (Ex-PHEV). This paper discusses the use of a multi-tasking Genetic Algorithm to optimize DGs with EVs planning in distribution systems for load models for rating and placement determination. From a system perspective, the goal of this research is to reduce total real power loss. The various types of DGs with EVs are taken into account from the standpoint of the analysis. Photovoltaic, diesel engines, synchronous condensers, and doubly-fed induction generators are examples of various types of DGs. In this analysis, EV types such as FCEV and Ex-PHEV are considered. Different forms of constant impedance (Z), constant current (I), and constant power (P) load models are included in DGs with EVs planning for improving system performance indices, such as Light-emitting diode, Laptop charger, Personal computer, Tungsten light, and Vacuum tube. The real power loss index (%ILP), the reactive power loss index (%ILQ), the voltage deviation index (%IVD), the short circuit current reduction (%IC), the active power DGs with EVs penetration (% PPWDGs & EVs), and the reactive power DGs with EVs penetration (%PQWDGs & EVs) are all measured in this paper. On the 37-bus test distribution system, the effectiveness of the listed approach was verified.This article is very much useful for researchers, industrial, scientific persons, and those who are working in the smart grid with DGs and EVs.

Electronic-Waste (E-Waste) Management and Minimization Practices: A Case Study of Dehradun District (Western Himalayan Region), Uttarakhand, India

The unprecedented generation of e-waste is a serious concern, which has become a critical environmental challenge across the world as well as considered as an emerging issue by policy makers, practitioners and researchers. The present paper deals with the case study conducted in four development blocks of Dehradun state (Doiwala, Sahaspur, Raipur and Vikasnagar) in Western Himalayan region from September 2020 to December 2021. We highlight standardized questionnaire based strategy including interviews of key stakeholders (Village head representatives, Education department, Development block officers, Representatives from Municipalities and Pollution Control Board) to evaluate present status of e-waste generation and awareness among communities. The results from the survey revealed that communities have low awareness level about e-waste management rules and regulations, its impact on environment and human health and formal and informal e-waste recycling processes. Besides, we organized training program to various stakeholders for making and repairing of LED bulbs, tube lights and creation of decorative sticks and bamboo carved lamps with respect to e-waste minimization and handling, which has resulted in providing a livelihood opportunity to the community. Folk media workshops (Short film, rap song, posters, leaflets, standees, puppet plays, street shows) were also organized together with launching of “EKU” (E-Waste Management and Minimization) campaign to spread awareness about systematic scientific management of E-waste in a simple and local language. Various e-waste minimization centers were established in Dehradun district on the basis of community recommendations. The study recommends that e-waste management, mitigation and recycling can be accelerated by promoting community awareness campaign, educating them about the benefits of scientific recycling of e-waste and making e-waste recycling as part of their livelihood source.

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.

Endoscopic and endoscopically assisted mini or less open sublay mesh repair (EMILOS and MILOS) of abdominal wall hernias: Update and 10-year experience of a single insitution

Introduction: Abdominal wall hernia and incisional hernia repair are among the most frequent operations in general surgery. However, despite the use of mesh and other recent improvements, the open mesh techniques and laparoscopic IPOM repair have specific disadvantages and risks. Materials and Methods: To minimize complications of the existing open and laparoscopic techniques we developed the endoscopic Mini- or Less Open Sublay (EMILOS) and endoscopically assisted Mini- or Less Open Sublay (MILOS) concept. We report on our large series of minimally invasive sublay repair of and ventral incisional hernias. The operation is performed transhernially with light-holding laparoscopic instruments either under direct, or endoscopic visualization, while the abdominal wall is circumferentially elevated with retractors. An endoscopic light tube was developed to facilitate this approach (Endotorch,TM Wolf Company). Each MILOS operation can be converted to standard total extraperitoneal gas endoscopy (EMILOS repair) once an extraperitoneal space of at least 8 cm has been created. The technique allows minimal invasive repair of ventral hernias with concomitant rectus diastasis. In large eventrations E/MILOS m. transversus abdominis release (TAR) can be performed. All MILOS operations were prospectively documented in the German Hernia registry Herniamed. Technical modifications and improvements from the inception of the E/MILOS concept including variants of the EMILOS technique are addressed. Results: The total and surgical complication rates of 1745 E/MILOS incisional hernia operations were 4.6% and 3.1%, respectively. The reoperation rate was 1.7%. Haemorrhage, seroma, enterotomy, infection and bowel obstruction were detected in 1.0, 0.9, 0.2, 0.3 and 0.4 percent of the cases, respectively. The recurrence rate after one year was 1.2%. Chronic pain at rest, at activities and chronic pain requiring therapy was reported in 3.8, 7.4 and 3.6 percent, respectively. Conclusion: The MILOS technique allows minimally invasive transhernial repair of incisional hernias using large retromuscular / preperitoneal meshes with low morbidity. The technique is reproducible, cost effective, easy to standardize and combines the advantages of open sublay and the laparoscopic IPOM repair.

Growth rate measurements of Chlorella vulgaris in a photobioreactor by Neubauer-improved counting chamber and densitometer

The depletion of fossil fuel sources and increased CO2 emissions has triggered intensive research to discover renewable energy sources. With the Low Carbon Scenario, the role of renewable energy will increase to 58% in 2050. As a renewable energy source, bioethanol is environmentally friendly which can substitute gasoline. Currently, the third-generation bioethanol production technology from microalgae is still being developed. Chlorella vulgaris is one of the microalgae types with high carbohydrate content and is easy and fast to cultivate. This study aims to evaluate the growth rate of C. vulgaris cultivated in a bubble column photobioreactor using artificial seawater aerated with pure CO2. Two LED tube lights were used with 12 h light and 12 dark cycles for 12 - 13 days. Microalgae culture population was measured every 24 h using a Neubauer-improved counting chamber and a microscope equipped with a digital camera. The results showed that the maximum specific growth rate,/max, was found to be 0.344 d1, and the highest concentration of 1.88 x107 cells mL1 occurred on day 7. Moreover, the microalgae populations were also measured using a densitometer. Since the calculation of the cell population used secondary data from the literature, the results were less accurate than those of the counting chamber.

Automated Energy Saving System Using Occupancy Sensor

Buildings consume large amount of energy in Pakistan such as: School/ University, office etc. As a result, a large amount of energy is being wasted. The largest and fastest-growing application for lighting controls is energy management. To reduce the electricity consumption in Electronic Department’s building, we first measured and analyzed the energy consumption of the building before and after the implementation of occupancy based energy saving systems. Occupancy sensors are used to control various devices (like Heating, ventilation and air conditioning devices, tube lights, fans, projector etc.). After studying various research papers, we came to the conclusion that by using occupancy sensors, we can save the energy of Electronic department up to 30% for lights, fans and projector. Almost all sensors which are used with the energy saving system use timer (preset) which will produce a time delay (when the last motion is detected by the sensor, the lights/fans will be turned OFF after certain period of time which is set by the timer). If this TD set by the Arduino is long then, it will save less energy, as the load will remain switched ON during unoccupied period also. At the same time, if the TD set by the Arduino is short then it may result in false detection (false OFF) of the lights and fan when there is no motion detected. In our research, we have observed that the energy consumption of may change over the day, also the activity of different user is different. Therefore, multiple time day will be suitable based on the activity of particular user. In this paper, we propose the design of automated energy saving system in which we will can change the time delay according to the needs of user. A model is also suitable for a person who is sitting at one position and working at a computer. Automated energy saving system had understood the variations in activity level of the user with respect to their working hours. Based on this information, it can change the time delay according to the working hours of the user. We have perform an experiment that our proposed system will save the additional 5% of the energy with multiple time delay.

A Comparative Analysis of Intermittent and Continuous Phototherapy in Patients with Neonatal Jaundice

Aim: To compare the outcome of intermittent phototherapy versus continuous phototherapy in treatment of neonatal jaundice.&#x0D; Study Design: Randomized clinical trial (RCT).&#x0D; Place and Duration: This study was conducted at Department of pediatrics, neonatal ward, Liaquat university hospital Hyderabad/Jamshoro, from 8 January to 7 July 2020&#x0D; Methodology: There were 222 neonate with jaundice, which were randomly allocated into two groups. One hundred and one neonates were in group “A” who received continuous phototherapy while 111 neonates were treated with intermittent phototherapy called group B. Phototherapy units were identical regarding their manufacture and radiance with 5 blue light tubes at a distance of 15-20 cm above neonate that produced the irradiance of 20µW/cm2/nm at 420-470 nm. Serum bilirubin levels were measured every 12 hourly after starting phototherapy up to 48 hours. SPSS version 22 was used for data analysis.&#x0D; Results: The average age of the neonates was 2.23±1.45 days. In this study, the reduction of bilirubin level in both groups after 12, 24, 36, 48 hours of phototherapy and at the time of discharge was not different between groups.&#x0D; Conclusion: Intermittent and continuous phototherapies were found to be equally effective. Because of its additional benefits, intermittent phototherapy can be adopted as a routine procedure instead of continuous phototherapy in neonatal care units, however, it needs to be confirmed by large scale RCTs.

Assessment the Visual Clarity of the Projector in Classroom and Innovative Asymmetric Distribution LED Tube Applications

The paper aims to explore the relationship between the vertical plane luminance on projection screens and human visual clarity in the classroom or meeting room. While controlling the lighting environment conditions of the classroom to create different luminous distributions and luminance on the projection screen, a survey is conducted to understand students’ visual experience about screen clarity during the field experiment. The luminance of each picture on the projection screen is measured under the specified lighting conditions of luminaires in the classroom, and the relationship is formulated between the average luminance on the projection screen and the visual satisfaction based on clarity of experience. This will be useful for further studying the acceptable threshold of luminance distribution in the classroom to provide a better visual clarity and lighting quality of projection screens while teaching. In this study, the measurement and performance evaluation on a projection screen were carried out at a classroom in the National Taiwan University of Science and Technology (NTUST). By using an image luminance meter and analyzing the research results, we propose an improvement strategy for asymmetric luminous distribution design of LED light tube and light switch control mechanism of luminaires to resolve the inadequate luminance of the vertical projection screen area to improve the lighting quality and visual clarity of the projection screen while teaching with the least cost.