Ceiling Lights Research Articles

Understanding the Common Defects in Commercial Buildings: Types, Causes and Remedial Actions

Commercial building maintenance management constitutes a pertinent issue of global concern for all related stakeholders. In Malaysia, the management of commercial building maintenance plays a crucial role in achieving the goal of providing safety to occupants and the building itself. However, there is a paucity of studies that have comprehensively explored all dimensions of commercial building defects in relation to maintenance management. This research was also conducted to identify and analyze the typical defects that occur in commercial structures, understand their underlying causes, assess their impact on safety, functionality and propose effective remedial actions. The study utilized a qualitative approach for data collection. The findings indicated that cracked floors, floor tile failures, wall tiles failure, damaged ceiling, paint peeling and faulty light bulbs were some of the flaws that degrade commercial building. The study’s outcome revealed that defects not only deface the aesthetic appearance of the commercial buildings but also inhibit the functionality of the buildings and depreciate the overall satisfaction. The research limitations include using commercial buildings (shopping complexes or malls) that have been operating for more than 20 years. This study offers invaluable insights for maintenance organizations and maintenance department staff who are genuinely interested in improving commercial buildings’ maintenance management to optimize staff’s performance and enhance the user satisfaction of the buildings in Malaysia and globally.

Broken Ceiling Lights: Circular Area Without the Radius

A customer walks in to a lighting store with a broken ceiling light, and the solution to finding a replacement glass illuminates an alternative approach to finding the circumference and area of a circle without knowing the circle’s center, radius, or diameter.

Using support vector machine to detect desk illuminance sensor blockage for closed-loop daylight harvesting

Daylight can reduce electric lighting in buildings. This is facilitated by sensors that relay real-time illuminance data to a light controller. When daylight provides greater than required or desired levels of illuminance, control actions enable electric lights to reduce their output and save energy. Occupant behaviours can block desk sensors and this reduces the amount of energy saved. However, no method exists that can be used to continuously monitor sensors to ensure they operate as intended (e.g. remain unblocked). We carried out a study in an open-plan office building in Singapore, consisting of 39 workstations each fitted with desk illuminance sensors independently controlling a dedicated ceiling light. Power over Ethernet was used to collect individual data signals for both illuminance and power from each workstation. Data were collected across a one month period, sampling signals at every 2-minute interval. A linear support vector machine model accurately classified 99% of the data points using our sensor blocking algorithm. From 447,455 data points analysed, 12% of dataset showed that sensors were blocked and this had an estimated energy penalty of 24%. We do not recommend installing illuminance sensors at the desk. Our study highlights the usefulness of Power over Ethernet for closed-loop daylight harvesting. The data collected can be used to monitor the health of the sensors’ performance to help minimise energy use.

Lighting techniques considering the safety and comfort of the elderly in the railway station space

Modern railway station spaces are being developed to be large and multifunctional through integration with commercial districts. They can go beyond their usual functions of transportation facilities to meet social requirements. The staircase space is a dynamic component of railway space where many users move simultaneously, and it requires appropriate safety measures. The objectives of this study are twofold: to clarify the effect of (1) the lighting environment of the staircase space and (2) the change in mounting height of the handrail lighting on mobility and safety. An on-site survey and impression evaluation of 28 railway stations in Tokyo indicated that illuminance and uniformity at the lower line of sight considerably affected the psychology of users. Therefore, handrail lights that can illuminate the surface of the stairs from a low position need to be installed to achieve a safe and comfortable light environment. No significant influence was detected based on the installation height of the handrail lighting; However, compared to the ceiling lighting, the handrail lighting was found to be higher in brightness, safety, and comfort items of impression evaluation. In addition, the elderly group evaluated the lighting environment with handrail lighting as more preference and safer than the young group.

A Novel Intraocular Lens Simulator that Allows Patients to Experience the World Through Multifocal Intraocular Lenses Before Surgeries.

PurposeThe purpose of this study was to investigate whether the intraocular lens (IOL) simulator can simulate how the world appears to patients with multifocal IOLs by allowing the patients to see far and near objects through the IOL simulator.MethodsTwenty eyes from 20 patients (age = 50–70 years old) were included in the study. The IOL simulator we developed consists of a trial lens frame adapter, a lens tube, a concave lens, a spacer, a wet cell, and an IOL. We used two IOLs: Tecnis monofocal and Tecnis bifocal IOL (add +3.25 diopter [D]). Patients wore a trial lens frame with an IOL simulator on distant corrected trial lenses and underwent the following tests: defocus curve, satisfaction with distance and near vision, halo around the light, and near point accommodation (NPA). To check how the world appears to the patients through this simulator, a machine vision lens and a scientific camera were attached to the simulator, and far and near objects were photographed.ResultsIn the defocus curve of multifocal IOL, the visual acuity showed the second peak at –4 D. Compared to monofocal IOL, satisfaction with distant vision was slightly worse, more halos were felt, satisfaction with near vision was higher, and the NPA was shorter in multifocal IOL. In the scientific camera test, through the multifocal IOL, the waiting room was blurry, the halo around the ceiling light was prominent, and the characteristics on the near visual acuity chart were clear.ConclusionSubjects could experience the functions of multifocal IOLs with our newly developed IOL simulator.Translational RelevanceThis IOL simulator using geometric optics allows patients to experience the function of multifocal IOLs before cataract surgery.

Future Perfect

Future Perfect

П’ЄЗОДАТЧИК ЯК ЕЛЕМЕНТ УПРАВЛІННЯ СВІТЛОМ ДЛЯ СТВОРЕННЯ ДИЗАЙНУ ДИТЯЧОГО ПРИМІЩЕННЯ

Purpose. Substantiation and creation of automatic lighting control in interactive rooms using piezoelectric converters. The introduction of this technology will significantly reduce energy consumption during the operation of such premises. The addition of further technological solutions based on the use of phosphor coatings and ultraviolet lighting will create a full range of innovative methods of child interaction in the social space.Methodology. The combination of piezo sensors with design elements such as "live" tiles as a trigger mechanism will create the necessary connection between the physical activity of the child and the regulation of light. The modern level of development and complete safety of materials such as phosphors in combination with specially designed point light sources will make it possible to create additional lighting and a field for the imagination of the child. Since the main attention when lighting children's rooms should be directed to the safe stay of the child, the use of light sources under a translucent floor will solve safety issues with a low level of energy consumption.Findings. An experimental study of the methods has proven the feasibility of using the proposed elements for any interactive children's room. The low cost of both equipment and the energy efficiency of all the technologies used is a significant advantage of this project over other developments with a large use of digital gadgets. The ability of create light of different spectral composition and color temperature is analyzed by using color filters and special light sources.Originality. The technologies and techniques presented in this work will be used for the first time to create interactive activities for a child. Separately, each technological solution was applied individually. This project combines separate developments to create a single interactive and light space. A low level of electricity consumption is achieved by using specially designed piezoelectric elements. Replacing standard ceiling lighting with lower (floor) lighting allows you to achieve the desired illumination using luminaires of lower power.Practical value. Recently, it has been proven that digitalization has a negative impact on the emotional state of the child and the only solution to replace it is to switch the child's attention to other more physically active actions. The proposed solutions in the work will allow their to be involved in group trainings. At the same time, the power consumption for obtaining such rooms will be much lower than the rest of the existing ones. The simplicity of the equipment and the possibility of variation during the operation of the premises make it available for creation in any institution of education, medicine, sports, etc.

Effect of ambient lighting conditions on tooth color quantification in cross-polarized dental photography: A clinical study

Statement of problemLimited data are available in the dental literature regarding the effect of ambient lighting on the consistency of color quantification in cross-polarized photography. PurposeThe purpose of this clinical study was to investigate the effects of ambient lighting conditions and postprocessing photograph calibration on color quantification in cross-polarized dental photography. Material and methodsTwelve volunteers with intact maxillary central incisors were recruited. Cross-polarized photographs were captured under light-emitting diode (LED), fluorescent ceiling, and natural lighting. The photographs were repeated after a 1-week interval, yielding a total of 72 photographs. The average Commission Internationale de l’Eclairage L∗a∗b∗ coordinates of the right central incisor were obtained with a software program before and after calibration by using a neutral gray reference card. The color difference (ΔE) values were calculated for each participant between the repeated photographs under the change and no change in illumination both before and after calibration. A 3-way repeated measures ANOVA was used to compare these values (α=.05). ResultsA statistically significant 3-way interaction was found between the illuminant type, change in illumination, and calibration (P<.001); however, all the ΔE values were within a clinically acceptable threshold (ΔE≤3.7). Before calibration, when photographs were captured under no change in illumination, LED lighting was found to have a significantly lower ΔE than fluorescent (P=.008) and natural and fluorescent lightings (P=.011), but when there was a change in illumination, no significant differences (P>.05) were found. After calibration, all the ΔE values were ≤1 and significantly lower than the values before calibration (P<.001). ConclusionsBoth the ambient illuminant type and change in illumination had minimal effects on ΔE. Calibration through the use of a neutral gray reference card was found to result in reduced and imperceptible color change (ΔE≤1) for all illuminant types.

Strategies to achieve optimum visual quality for maximum occupant satisfaction: Field study findings in office buildings

For visual quality, the traditional focus on illuminance for paper-based tasks and brightness contrast for visual acuity is becoming less relevant in modern offices with backlit computer screens and sporadic use of paper. This research aims to investigate critical correlations between user satisfaction, workstation lighting conditions, and the physical attributes of the work area. The statistical analyses were conducted to identify applicable recommendations leading to improved visual quality in today's work environment while maintaining optimal user satisfaction.Findings from post-occupancy evaluation on 1,232 workstations in 64 office buildings revealed that satisfaction level would increase by 20% on average when the occupants have a view to the outside in their seated workstations. Upgrading the ceiling light fixture with an indirect lens type increases visual satisfaction. Workstations with an indirect lens type had higher satisfaction (62%), while a prismatic ceiling lens type showed the lowest user satisfaction (34%). The analysis further identified that a combination of indirect light fixtures with task lights increases user satisfaction by 21%. Lastly, utilizing window shading devices revealed greater satisfaction with glare management. The occupants with external and internal shading devices in their work areas showed the highest satisfaction with their overall lighting. In addition to the recommendations mentioned above, an illuminance level of 406 lux for the work surface achieves maximum satisfaction in contemporary office environments.

The Null Effect of UVC Ceiling Light Exposure on SARS-CoV2

There has been some extensive research investigating the effect of Far Ultraviolet Radiation (UVC) on SARS and MARS. However, to the best of our knowledge, there have not been any detailed experiments looking at the effect of UVC on COVID-19 (now is called SARS-CoV2). Many researchers in this field believe that UVC destroys SARS-CoV2 because it warps the genetic material of the virus hurdling the viral particles from reproduction. In this paper, we report the result of our novel experiments on the effect of UVC on SARS-CoV2 using a commercially available UVC source, i.e. Krypton Disinfection lighting CM15W12V Series (wavelength of 222 nm), which is sold and marketed for the disinfection of pathogens. The experiments were extended to study the effect of UVC exposure to Bacteria and Fungus. Our experiments show that UVC has no effects on SARS-CoV2 when it is close to the SARS-CoV2 culture plate (4 - 5 cm) or at a distance (2.0 to 2.9 m), i.e. when fixed at the ceiling. This observation is important as the public seems to have the impression that commercial UVC ceiling light can kill SARS-CoV2 while this study has proven the opposite. Moreover, it shows no effect even when the UVC ceiling light is radiating on SARS-CoV2 for overnight. This proves that the intensity of the UVC from these devices is relatively low. However, the UVC light is found to be effective in destroying Bacteria and Fungus (part of pathogens), substantially, in 30 sec, and completely kills them when it’s at 2.9 m (or less) away from them and exposure for one day. This indicates that the UVC light is effective for bacteria disinfection.

Efficacy of an ultraviolet-A lighting system for continuous decontamination of health care–associated pathogens on surfaces

We found that ultraviolet-A (UV-A) light exposure resulted in a modest reduction in recovery of methicillin-resistant Staphylococcus aureus (MRSA), Candida auris, bacteriophage MS2, and bacteriophage Phi X174, but not Clostridioides difficile spores, on steel disk carriers. Four hours of UV-A exposure from a ceiling light fixture resulted in a significant reduction in pathogenic microorganisms recovered from in-use medical equipment. These findings suggest that UV-A could be useful as a means to provide continuous low-level decontamination of surfaces in health care facilities.

Visible Light Communication System Based on Software Defined Radio: Performance Study of Intelligent Transportation and Indoor Applications

In this paper, our first attempt at visible light communication system, based on software defined radio (SDR) and implemented in LabVIEW is introduced. This paper mainly focuses on two most commonly used types of LED lights, ceiling lights and LED car lamps/tail-lights. The primary focus of this study is to determine the basic parameters of real implementation of visible light communication (VLC) system, such as transmit speed, communication errors (bit-error ratio, error vector magnitude, energy per bit to noise power spectral density ratio) and highest reachable distance. This work focuses on testing various multistate quadrature amplitude modulation (M-QAM). We have used Skoda Octavia III tail-light and Phillips indoor ceiling light as transmitters and SI PIN Thorlabs photodetector as receiver. Testing method for each light was different. When testing ceiling light, we have focused on reachable distance for each M-QAM variant. On the other side, Octavia tail-light was tested in variable nature conditions (such as thermal turbulence, rain, fog) simulated in special testing box. This work will present our solution, measured parameters and possible weak spots, which will be adjusted in the future.

Passive Ceiling Light Disinfection System to Reduce Bioburden in an Intensive Care Unit.

A ceiling-installed narrow spectrum (402-420 nm) bactericidal blue light disinfection system was installed in a large suburban medical intensive care unit (ICU) and evaluated for implementation feasibility and effectiveness in reducing environmental bioburden. Installation of 54 ceiling devices was accomplished at low cost and with minimal ICU process disruption. Postinstallation high-touch surface colony counts were significantly lower than preinstallation. Linear mixed modeling demonstrated a 21% average overall decrease in colony count after installation, with consistent reduction in colony counts starting from week 4 postinstallation. Automated technology is potentially more efficient in reducing environmental bioburden in the acute care setting compared with other bioburden reducing methods or can provide a robust compliment to manual cleaning.

Operation Field Illuminance in Dentistry

Dental treatment zone and operation field illuminance estimation were made in this study. Treatment zone illuminance was 500 lx under conventional fluorescent lamp based lighting and 1000 lx in a case of additional ceiling light use. Operation field illuminance under a dental operating light varied from 4000 lx to 14000 lx in dependence on an oral cavity zone and a patient position. The maximal illuminance level was achieved at upper incisors in a patient supine position, the minimal one was achieved at upper molars in patient upright position. Using of light emitting diode (LED) headlight increased the illuminance up to 2000 lx in average. The use of intraoral light sources provided adequate operating field illuminance in range (7000–18000) lx in molars area where illumination of dental operating light are not enough. The study results allow recommendation of ceiling lights and intraoral lights as additional light sources.

실제 천공의 스펙트럼과 이미지를 구현하기 위한 인공 창문 조명기구의 다채널 LED 조합비율 계산

To plan human centric lighting suitable for occupants, it is desirable to provide light similar to daylight. In order to provide light similar to daylight, a number of researches have been conducted on a methodology of realizing a spectrum similar to a daylight spectrum by combining a light emitting diode (LED) chip having a specific peak wavelength. The spectrum matching methodology proposed in previous studies offers monochromatic artificial lighting that resembles spectrum of daylight. If the methodology is applied to artificial luminous ceiling or artificial window lighting installed for communication with the outside without daylight, monochromatic light cannot be expected to give satisfactory communication effect for occupants even if its spectrum is same as daylight. Accordingly, this study developed a methodology for calculating combination ratio of multi LED chips matched with spectrum of daylight and embodying non-monochromatic real sky image for artificial luminous ceiling or artificial window lighting that can be applied to underground space, windowless space, submarine, and so in.

The Impact of Environmental Light Intensity on Experimental Tumor Growth

Cancer research requires for consistent models that minimize environmental variables. Within the typical laboratory animal housing facility, animals may be exposed to varying intensities of light as a result of cage type, cage position, light source, and other factors; however, studies evaluating the differential effect of light intensity during the light phase on tumor growth are lacking. The effect of cage face light intensity, as determined by cage rack position was evaluated with two tumor models using the C57Bl/6NHsd mouse and transplantable B16F10 melanoma cells or Lewis lung carcinoma (LLC) cells. Animals were housed in individually-ventilated cages placed at the top, middle, or bottom of the rack in a diagonal pattern so that the top cage was closest to the ceiling light source, and cage face light intensity was measured. Following a two-week acclimation period at the assigned cage position, animals were subcutaneously administered either 1.3×106 B16F10 melanoma cells or 2.5×105 Lewis lung carcinoma cells. Weights of excised tumors were measured following euthanasia 18 days (melanoma) or 21 days (LCC) after tumor cell administration. Cage face light intensity was significantly different depending on the location of the cage, with cages closest to the light source have the greatest intensity. Mean tumor weights were significantly less (p<0.001 for melanoma; p≤0.01 for LCC) in middle light intensity mice compared to high and low light intensity mice. The environmental light intensity to which experimental animals are exposed may vary markedly with cage location and can significantly influence experimental tumor growth, thus supporting the idea that light intensity should be controlled as an experimental variable for animals used in cancer research.

Performance analysis and optimization of unipolar OFDM based relay-assisted visible light communications☆

In this paper, we consider a relay-assisted visible light communication (VLC) system where an intermediate light source cooperates with the main light source. Following the IEEE 802.15.7r1 VLC reference channel model, we assume the presence of two different light sources in an office space. The first one is the ceiling light that serves as the source terminal while the second one is the desk lamp that serves as the relay terminal. Our system builds upon unipolar optical orthogonal frequency division multiplexing (U-OFDM) where the desk light performs amplify-and-forward relaying to assist the ceiling light and operates in a half-duplex mode. In addition, we consider the use of enhanced U-OFDM (eU-OFDM) which doubles the spectral efficiency of U-OFDM at the expense of additional computational complexity. We analyze the bit error rate performance of the relay-assisted VLC system building on these two OFDM types and quantify performance improvements over point-to-point (i.e., no relaying) VLC systems. In an effort to further improve system performance, we investigate optimal power allocation between source and relay terminals.

Achieving high sound isolation between rooms with stone wool ceilings and plenum barriers when the ceiling grid runs continuously over partial height demising walls

The Optimized Acoustics Research Program is a multi-year investigation being conducted by ROCKFON, ROXUL, and NGC Testing Services into efficient and economical means of constructing interior architecture that complies with the higher sound absorption and higher sound isolation criteria in standards, guidelines, and building rating systems. Prior program updates have included the negative effects of noise flanking paths through ceiling light fixtures and air distribution devices (Inter-Noise 2015) and optimizing the combination of absorptive, stone wool, ceilings and lightweight plenum barriers to achieve sound transmission class (STC) ratings of 40, 45, and 50 without full height demising walls (Noise-Con 2016). This update addresses a worst-case scenario, when the suspended ceiling grid runs continuously over partial height demising walls. Building the walls to the underside of the ceiling grid avoids the need to reconstruct the ceiling if the walls are relocated in the future. However, this approach has historically not complied with the standards and results in poor acoustic performance. The current research shows how to install standard 16 mm (5/8 in.) thick, stone wool, modular, acoustic ceilings and 38 mm (1.5 in.) thick stone wool plenum barriers to achieve ratings up to STC 52.

Self-Position Measurement for Indoor Using Ceiling LED Lights

Automatic guided vehicles (AGVs) are widely used in various manufacturing factory such as automobile fabrication factory. The popular guiding method is magnetic induction method, but it needs a lot of effort and time when the travel route is changed. In this study, we proposed a new method to detect the coordinate of an AGV for its auto guiding. The indoor ceiling light emitting diode (LED) lights are utilized as lighting marker, which are modulated with different frequencies. A photodiode is set on the AGV and receive the LED light to determine the coordinates of the AGV. Experimental results showed this new method can achieve enough accuracy under 50cm for AGV coordinate detection.

Enhancement of autonomic and psychomotor arousal by exposures to blue wavelength light: importance of both absolute and relative contents of melanopic component

BackgroundBlue light containing rich melanopsin-stimulating (melanopic) component has been reported to enhance arousal level, but it is unclear whether the determinant of the effects is the absolute or relative content of melanopic component. We compared the autonomic and psychomotor arousal effects of melanopic-enriched blue light of organic light-emitting diode (OLED) with those of OLED lights with lesser absolute amount of melanopic component (green light) and with greater absolute but lesser relative content (white light).MethodsUsing a ceiling light consisting of 120 panels (55 × 55 mm square) of OLED modules with adjustable color and brightness, we examined the effects of blue, green, and white lights (melanopic photon flux densities, 0.23, 0.14, and 0.38 μmol/m2/s and its relative content ratios, 72, 17, and 14%, respectively) on heart rate variability (HRV) during exposures and on the performance of psychomotor vigilance test (PVT) after exposures in ten healthy subjects with normal color vision. For each of the three colors, five consecutive 10-min sessions of light exposures were performed in the supine position, interleaved by four 10-min intervals during which 5-min PVT was performed under usual fluorescent light in sitting position. Low-frequency (LF, 0.04–0.15 Hz) and high-frequency (HF, 0.15–0.40 Hz) power and LF-to-HF ratio (LF/HF) of HRV during light exposures and reaction time (RT) and minor lapse (RT >500 ms) of PVT were analyzed.ResultsHeart rate was higher and the HF power reflecting autonomic resting was lower during exposures to the blue light than the green and white lights, while LF/HF did not differ significantly. Also, the number of minor lapse and the variation of reaction time reflecting decreased vigilance were lower after exposures to the blue light than the green light.ConclusionsThe effects of blue OLED light for maintaining autonomic and psychomotor arousal levels depend on both absolute and relative contents of melanopic component in the light.