Conventional Lighting Research Articles

Darkness increases the population growth rate of the poultry red mite Dermanyssus gallinae

BackgroundThe poultry red mite (PRM), Dermanyssus gallinae, is one of the most economically deleterious ectoparasites affecting egg-laying hens worldwide. It may be possible to control D. gallinae populations by manipulating lighting regimes within poultry units. However, no studies have clearly shown the effects of darkness on the population growth rate of D. gallinae.MethodsThe effect of darkness on the population growth rate of D. gallinae was investigated, together with the first description of the molecular identity of the mite from China. Mite variables under two lighting regimens (1:23 h L:D and 12:12 h L:D) were compared, including number of mites and eggs, survival and feeding rates, engorgement, oviposition, hatchability and the life-cycle of D. gallinae.ResultsThe results showed that the number of mites (13,763 ± 956) and eggs (5424 ± 317) in the rearing system with prolonged darkness of 1:23 h L:D at 4th week were 2.4- and 3.6-fold higher than those under a conventional lighting regimen of 12:12 h L:D, respectively. The feeding rates of mites under prolonged darkness ranged from 36.7 ± 1.1% to 52.0 ± 7.0%, which were significantly higher than those under conventional lighting regimen (ranging from 22.6 ± 1.9% to 37.3 ± 1.6%). The mean weight of engorged females (0.26 ± 0.01 mg) and the mean number of eggs per female (on average 5.87 ± 0.36) under prolonged darkness were significantly higher than those under conventional lighting regimen (0.22 ± 0.01 mg and 3.62 ± 0.31, respectively). However, the survival rate ranging from 98.07 ± 0.10% to 98.93 ± 0.19%, hatchability of 97.93 ± 0.01% and the life-cycle of D. gallinae (9 days) was not affected by the lighting period.ConclusionsOur findings demonstrated that prolonged darkness significantly promoted the proliferation levels of D. gallinae, resulting in increased number of mites and eggs in the rearing system. The promoted population growth of D. gallinae was found to be related to the increased feeding rate, engorgement level and oviposition level of mites under prolonged darkness. The egg hatchability, the survival rates and the duration of life-cycle of D. gallinae were not affected by the light regimes.

Current Review of the Modulatory Effects of LED Lights on Photosynthesis of Secondary Metabolites and Future Perspectives of Microgreen Vegetables.

Light-emitting diode (LED) lights have recently been applied in controlled environment agriculture toward growing vegetables of various assortments, including microgreens. Spectral qualities of LED light on photosynthesis in microgreens are currently being studied for their ease of spectral optimization and high photosynthetic efficiency. This review aims to summarize the most recent discoveries and advances in specific phytochemical biosyntheses modulated by LED and other conventional lighting, to identify research gaps, and to provide future perspectives in this emerging multidisciplinary field of research and development. Specific emphasis was made on the effect of light spectral qualities on the biosynthesis of phenolics, carotenoids, and glucosinolates, as these phytochemicals are known for their antioxidant, anti-inflammatory effects, and many health benefits. Future perspectives on enhancing biosynthesis of these bioactives using the rapidly progressing LED light technology are further discussed.

LED Grow Lights Alter Sorghum Growth and Sugarcane Aphid (Hemiptera: Aphididae) Plant Interactions in a Controlled Environment

Normal growth and production of plant tissues requires water, carbon dioxide, nutrients, and light. Light-emitting diodes (LED) are being used increasingly as a substitute for fluorescent or incandescent light sources in greenhouse horticulture because of their small size, durability, wavelength specificity, long operating life, and efficiency in offering photosynthetically active radiation at lowered energy costs compared to conventional lights. However, studies conducted to test the effects of these lights reveal that spectral properties of light-emitting diodes can have dramatic effects on plant morphology, nutrient uptake, and pathogen development when plants are grown under the incorrect light spectrums. We grew sorghum plants under a light-emitting diode grow panel, and compared it to plants grown under conventional fluorescent lighting within identical environmental chambers. Light-emitting diode lighting resulted in deleterious sorghum growth with fewer true leaves formed, reduced plant height, lower chlorophyll content, and an unusual pink to purple coloration of the plant tissue when compared to sorghum grown under conventional lighting. All 4 of the different sorghums grown under light-emitting diodes had 2× the amount of biomass measured as dry weights for upper (stems and leaves) and lower (root mass) when compared to the conventional lighting. When sorghums were infested with sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), both light sources supported a similar number of aphids but plants grown under light-emitting diodes had higher damage ratings than those under conventional lights for both known resistant and susceptible sorghums. For future trials, sorghum should not be grown using the light-emitting diode lights when assessing host-plant resistance to aphid infestation.

Multi Function Electric Pole

Today electricity is a major concern worldwide and most of the power generation stations are based on conventional fuels like coal but we have limited sources of these non renewable fuels. So as to minimize the dependence on these sources, we have to move on to new and renewable sources like solar and wind, etc. However proper usage of electricity could also be one of the effective tools for saving the conventional fuels. Street lights are one of the most crucial parts for public lighting systems which consume a major part of the generated electricity. The conventional or manual controlled street lighting system has demerits like high power consumption, high cost and absence of effective monitoring system. This paper describes an energy efficient approach of multi-functional electric pole, which can generate electricity using wind and solar resources. This system can effectively overcome the demerits of any conventional street lighting system.

Impact of urban street lighting on road users’ perception of public space and mobility behavior

Refitting public spaces with light-emitting diode (LED) technology in lieu of conventional luminaires bears the risk of compromising lighting quality that road users have already adapted to; this is because the LED technology has been well tested indoors, but it has not been necessarily evaluated outdoors. Further insight into the effects of street lighting on road users is necessary to resolve potential deficiencies of available technologies. This study compares the effects of three different lighting scenarios (conventional lighting, state-of-the-art LED, optimized LED) on road users via surveys (N = 598 persons) and observations (N = 1341 persons) in the city of Vienna. In terms of the uniformity of street illumination and the comfort it provides, the results show the positive effects of LED street lighting both on surveyed pedestrians and vehicle drivers. The observations of pedestrian walking behavior revealed an unexpected result—no significant differences were noted apart from a more centric walking path along the sidewalk under LED illumination, particularly with the optimized LED luminaire.

ReViCEE: A recommendation based approach for personalized control, visual comfort & energy efficiency in buildings

Built-environment, especially open-plan workplaces are often not tailored to meet individual visual comfort needs. Therefore, meeting the need for personalized visual comfort whilst achieving energy efficiency in open-plan office environment has been an open challenge. However, recent technological advancements in distributed sensing, pervasive computing, context-awareness and machine learning is progressively closing this gap. This article introduces ReViCEE–a simple recommender systems based approach to learn both individual and collaborative user-preferences from historical data and offer recommendations for intelligent building lighting controls. The intelligence in this case is achieved by being able to derive set-points to control task lights such that it balances personalized visual comfort without compromising on energy savings. The proposed approach has been developed using Python and implemented on a real test-bed in an university campus office building in National University of Singapore. The evaluation of the proposed approach is carried out for two months using field experiments involving distributed wireless sensor actuator network (WSAN) and multiple occupants having varied visual sensation. The novelty lies in proposing a new inter-disciplinary approach that supports smart and intelligent buildings paradigm by learning and predicting optimum individual user-preferences towards energy efficient control of personalized light. The results obtained from field experiments present a potential energy savings upto 72% when compared to the conventional lighting systems used.

How Do White LEDs’ Spectra Affect the Fresh Weight of Lettuce Grown under Artificial Lighting in a Plant Factory?—A Statistical Approach

Monochromatic light-emitting diode lamps (LEDs), emitting red and blue lights, revolutionized crop production in closed-system plant factories with artificial lighting in the early 1990s. The LED industry developed broad-spectrum white-LEDs by 2010, and many types of white-LEDs for home and office uses are now available for plant factory entrepreneurs. This paper tries to clarify whether these white-LEDs can be used as effective light sources in plant factories by examining what types of spectrum distribution are better suited for plant production. An experiment was conducted using seven LEDs, of which six were white-LEDs, to compare the performance in producing lettuce, and the results were compared with recent studies that used white-LEDs for growing lettuce under closed-system production conditions. Results showed that broad-spectrum white-LEDs performed significantly better than narrow-spectrum LEDs. Among lights in conventional color bands, red and blue lights give critical effects on plant growth, not in isolation but in combination; not too “cool” white LEDs perform better. Green and far-red lights also have some positive effects. Altogether, for a given light intensity, broad-spectrum white LEDs outperform narrow-spectrum LEDs. It is found that the spectrum distribution for white-LEDs to attain high productivity in lettuce production is such that the percentage share of photon flux density by conventional color band falls in the following ranges: 0% < blue < 30%, 0% < green < 50%, 30% < red < 70%, and 0% < far-red < 20%.

IoT Green Corridor

IoT Green Corridor is a distributed sensor network system, a working prototype of which has been designed in-house and using low-cost hardware for economically-viable implementation. This paper outlines the development of the prototype and describes its details. This proposed system combines the existing conventional traffic signal lights with networked-sensors across length and breadth of connected and usually-congested city roads. Being connected to the internet, the sensors are better-enabled and capable of synchronizing with each other for sharing localized traffic information including the presence of emergency vehicles like ambulances. Having been equipped with the situational awareness data, the sensor network in an IoT framework is capable of collective decision to manage a given set of the traffic signal lights in tandem to achieve the singular aim of providing smooth passage to the arriving ambulances or in general to any Emergency Vehicle (EMV). Every traffic-signal junction is to be retrofitted with the Green Corridor system prototype, which is required to sense the presence of an Emergency Vehicle (EMV) within a specified distance in the field of view of the sensors. Based on a positive identification of such vehicles in distress, the traffic flow is designed to quickly enable the EMV to cross the junction smoothly in least time as possible. In the absence of a system of this kind, a manual intervention would have to be made by the concerned agency or valuable golden hour time to save lives would be spent in the traffic junctions. Besides, the prototype communicates with the inter-connected adjacent sensor-network elements through the cloud network to initiate similar action at each of the traffic signals enroute the desired destination of the emergency vehicle.

Polymer light emitting diodes (PLEDs): An update review on current innovation and performance of material properties

Abstract Conventional lighting systems, such as the incandescent light bulbs used on the offshore oil rigs are becoming obsolete due to high energy consumption, poor life span and additional costs of waste treatment and disposal. Furthermore, they are susceptible to fire when exposed to an oxygen rich environment, posing a threat to the oil rig workers. Recent advances have led to the development of polymer light emitting diodes (PLEDs) as substitutes to these prevailing light sources. The PLEDs have advantages over the incandescent bulbs, for being durable, low energy consumption and environmental friendly. Consequently, the increasing research collaborations among the academic researchers and industrial stakeholders are gaining momentum in ensuring the advancements of PLEDs in terms of economic value and performance. This paper is aimed at reviewing the recent advances in the field of current innovation and performance of PLEDs materials. The paper focuses on the important experiments on the PLEDs materials towards the upgrading and modification of anode and holes injection/transporting layer and the influence of doping effect. In spite of that, this paper discovered that synthetic materials, such as synthetic silicates are the commonly used materials in the current PLEDs, and recommends the incorporation of cost effective inorganic clay-polymer nanocomposite-based LEDs as a way forward to reducing the material costs and provide more environmental friendly PLEDs materials.

Emission and Color Tuning of Cyanostilbenes and White Light Emission.

White-light-emitting diodes are energy efficiency replacement of conventional lighting sources. Herein, we report the luminescent behavior of three simple cyanostilbenes with triphenylamine-donating groups bearing different electron-withdrawing groups (phenyl, pyridyl, and p-nitrophenyl) in a common donor (D)−π–acceptor (A) α-cyanostilbene construct along with their thermal and electrochemical properties. The density functional theory (DFT) studies reveal that aggregation-induced emission characteristic feature of the D−π–A dyes is inversely proportional to the intramolecular charge transfer (ICT) effect, that is, phenyl-and pyridyl-substituted compounds show characteristic aggregation-induced emission in water, whereas the ICT effect is dominant for the nitro derivative. The extent of ICT and the solvatochromic emission shifts, from blue to red, depend on the strength of the electron-withdrawing group. White luminescence and tunable emission colors are obtained by careful admixtures of these cyanostilbenes bearing triphenylamines. The results rationalized through DFT and time-dependent DFT calculations follow a consistent trend with the energy levels measured from the electrochemical and optical studies. Thermogravimetric analysis and differential scanning calorimetry studies showed excellent thermal stability of the compounds. The scanning electron microscopy and dynamic light scattering measurements were performed to reveal the formation of aggregates. This strategy involving synthetically simple and structurally similar molecules with different emission properties has potential applications in the fabrication of multicolor and white-light-emitting materials.

Adaptive homeostasis of the vitamin D–vitamin D nuclear receptor axis in 8-methoxypsoralen-induced hepatotoxicity

8-methoxypsoralen (8-MOP) with ultraviolet A radiation therapy (PUVA) is the standard therapy for patients with psoriasis, despite the reported potential risks of 8-MOP-induced cholestatic liver injury in both humans and animals. Usually, patients with chronic cholestasis exhibit lower serum 25-hydroxy vitamin D (25(OH)D) levels. But those patients receiving PUVA for psoriasis showed an increase in serum 25(OH)D levels, probably highlighting that the vitamin D–vitamin D nuclear receptor (VD-VDR) axis play a protective role in 8-MOP-induced hepatotoxicity. The present study confirmed 8-MOP could increase serum 25(OH)D levels in conventional lighting and diet (CLD) and vitamin D deficient (VDD) Sprague-Dawley rats. Potential liver risks were also found in CLD and VDD rats after 8-MOP treatment. We proved that 8-MOP could be a potent ligand for VDR using molecular docking and luciferase report assay. Effect of 8-MOP on VDR subcellular distribution was determined using human liver cell line L02. We found 8-MOP could increase VDR protein expression in the nuclear and cytosol extracts and also total cell extracts in L02. siRNAs for VDR were used to determine the role of VDR in protecting 8-MOP-induced cholestasis and potential cellular mechanisms. The results showed 8-MOP could affect the CYP7A1, SHP and MRP3 expression via VDR, and such effects could be reversed by knockdown of VDR expression, suggesting a vital role of VDR involved in 8-MOP-regulated bile acid synthesis and transportation. In conclusion, these results revealed activation of VD–VDR axis may play a beneficial role in 8-MOP-mediated regulation of bile acid synthesis and transportation.

A Low-Cost Linear LED Driver for Light Bulb Based on Harmonic Standard

Since lighting system is used in every human activity, an electronic device with more power efficient and low cost, rather than electrical equipment, has been developed. HPLED (High Power Light Emitting Diode) has been applied in many aspects to replace the conventional lighting. A significant part of the system is LED Driver, which is important to improve efficiency, adjusted voltage and current output. Some problems may occur and cause harmonic distortion. There are two types of drivers commonly developed such as Linear Driver and Switching Driver. Linear driver is a circuit easier to implement and to find error compared to switching driver. A linear LED driver circuit must fit the Harmonic Standard requirements. In this study, some comparisons and measurements due to IEEE 519-1992 and IEC 61000-3-2 standards were conducted to evaluate the power quality. The results showed that the measurement of Linear Driver using LM 317 and IN4733 in accordance to the Harmonic Standard were PF 0.92, THDi 37.5%, THDv 1.9% for LM317 Driver and PF 0.86, THDi 25.4% and THDv 2.1% for IN4733A, respectively.

사용자 행동패턴을 고려한 선박 선실의 침상 조명 디자인 및 조명기구 개발에 관한 연구

In this paper, we studied the customized design for LED berth light of ship cabin based on the user’s behavior pattern analysis and lighting environment investigation. We studied the lighting design target, product design, design simulation, preparation of a prototype with a bidirectional radiation luminaire, and then measured and analyzed the lighting characteristics and lighting atmosphere. Upward lighting provides indirect illumination through the reflection to ceiling of the bed for the rest or sleep activities, whereas downward lighting provides enough illumination to the bed plane for the working or reading activities. In addition, illuminance and correlated color temperature (CCT) control was enabled by adopting warm and cool white LEDs with dimming. The prototype had the enhanced performance with α, δ, θ brain wave effect depending on the user’s behavior pattern and the improved berth lighting atmosphere was closely matched to user’s behavior patterns. The prototype was shown the better lighting performance with high flux, reduced glare and increased lighting efficiency compared to the conventional lighting fixtures.

PFC Control for LED Lamp Driver Using Sensorless Predictive Current Controller

Light-emitting diodes (LEDs) have recently become of utmost significance to replace conventional lighting sources. Power factor correction (PFC) control of LED lamps requires three sensors which cause more cost, increase time delay, and increase noise, thus reducing drive reliability. Alternative methods to estimate the inductor current instead of its measurement are mandatory. This paper proposes a sensorless predictive current controller to enhance power factor (PF) of LED lamp driver and reduce driver cost. The inductor current is estimated instead of employing current sensor relying on measured input and output voltages. Zero-crossing detector is utilized to accomplish robust performance during distorted supply voltage. The controller and power circuit are isolated. The control algorithm employs a two-loop control to achieve a high PF with sinusoidal input current. Rapid speed performance is accomplished. The influences of PFC on input current value, PF and harmonic orders are presented. A prototype LED lamp driver with the suggested PFC structure is tested practically by a digital signal processor (DSP) DS1104 platform to validate its effectiveness. Experimental tests under various working conditions are provided to prove the usefulness of the suggested PFC control.

The development and evaluation of Robot Light Skin: A novel robot signalling system to improve communication in industrial human–robot collaboration

Abstract In a human–robot collaborative production system, the robot could make request for interaction or notify the human operator if an uncertainty arises. Conventional industrial tower lights were designed for generic machine signalling purposes which may not be the ultimate solution for robot signalling in a collaborative setting. In this type of system, human operators could be monitoring multiple robots while carrying out a manual task so it is important to minimise the diversion of their attention. This paper presents a novel robot signalling solution, the Robot Light Skin (RLS),which is an integrated signalling system that could be used on most articulated robots. Our experiment was conducted to validate this concept in terms of its effect on improving operator's reaction time, hit-rate, awareness and task performance. The results showed that participants reacted faster to the RLS as well as achieved higher hit-rate. An eye tracker was used in the experiment which shows a reduction in diversion away from the manual task when using the RLS. Future study should explore the effect of the RLS concept on large-scale systems and multi-robot systems.

Migratory bats are attracted by red light but not by warm-white light: Implications for the protection of nocturnal migrants.

The replacement of conventional lighting with energy‐saving light emitting diodes (LED) is a worldwide trend, yet its consequences for animals and ecosystems are poorly understood. Strictly nocturnal animals such as bats are particularly sensitive to artificial light at night (ALAN). Past studies have shown that bats, in general, respond to ALAN according to the emitted light color and that migratory bats, in particular, exhibit phototaxis in response to green light. As red and white light is frequently used in outdoor lighting, we asked how migratory bats respond to these wavelength spectra. At a major migration corridor, we recorded the presence of migrating bats based on ultrasonic recorders during 10‐min light‐on/light‐off intervals to red or warm‐white LED, interspersed with dark controls. When the red LED was switched on, we observed an increase in flight activity for Pipistrellus pygmaeus and a trend for a higher activity for Pipistrellus nathusii. As the higher flight activity of bats was not associated with increased feeding, we rule out the possibility that bats foraged at the red LED light. Instead, bats may have flown toward the red LED light source. When exposed to warm‐white LED, general flight activity at the light source did not increase, yet we observed an increased foraging activity directly at the light source compared to the dark control. Our findings highlight a response of migratory bats toward LED light that was dependent on light color. The most parsimonious explanation for the response to red LED is phototaxis and for the response to warm‐white LED foraging. Our findings call for caution in the application of red aviation lighting, particularly at wind turbines, as this light color might attract bats, leading eventually to an increased collision risk of migratory bats at wind turbines.

A comparison of four different imaging modalities – Conventional, cross polarized, infra-red and ultra-violet in the assessment of childhood bruising

BackgroundIt is standard practice to image concerning bruises in children. We aim to compare the clarity and measurements of bruises using cross polarized, infra-red (IR) and ultra-violet (UV) images to conventional images. MethodsChildren aged <11 years with incidental bruising were recruited. Demographics, skin and bruise details were recorded. Bruises were imaged by standard protocols in conventional, cross-polarized, IR and UV lights. Bruises were assessed in vivo for contrast, uniformity and diffuseness, and these characteristics were then compared across image modalities. Color images (conventional, cross polarized) were segmented and measured by ImageJ. Bruises of grey scale images (IR, UV) were measured by a ‘plug in’ of ImageJ. The maximum and minimum Feret's diameter, area and aspect ratio, were determined. Comparison of measurements across imaging modalities was conducted using Wilcoxon rank sum tests and modified Bland-Altman graphs. Significance was set at p < 0.05. ResultsTwenty five children had 39 bruises. Bruises that were of low contrast, i.e. difficult to distinguish from surrounding skin, were also more diffuse, and less uniformity in vivo. Low contrast bruises were best seen on conventional and cross-polarized images and less distinctive on IR and UV images. Of the 19 bruises visible in all modalities, the only significant difference was maximum and minimum Feret's diameters and area were smaller on IR compared to conventional images. Aspect ratios were not affected by the modality. ConclusionsConventional and cross-polarized imaging provides the most consistent bruise measurement, particularly in bruises that are not easily distinguished from surrounding skin visually.

Miniature ureteroscope distal tip designs for potential use in thulium fiber laser lithotripsy.

Thulium fiber laser lithotripsy using smaller optical fibers may enable development of miniature ureteroscopes. Two ureteroscope distal tip prototypes were built and characterized. The first design was 4.5-French (Fr) [1.5-mm outer diameter (OD)], five channel tip, housing 200-μm inner diameter (ID) dedicated central channel for insertion of 100-μm core fibers and four surrounding channels, each with 1.5Fr (510-μm ID) for instrumentation, irrigation, imaging, and illumination, respectively. The second design was 6.0-Fr (2.0-mm OD), three-dimensional printed tip with larger, hemispherical common working channel and separate detection port integrated with ring lighting. Standard instruments, including optical fibers, guidewires, and stone baskets, were inserted through working channels to demonstrate feasibility. Gravitational and manual pump-assisted saline irrigation rates were measured. Luminous intensity distribution curves (LIDCs) were modeled for both ring and conventional lighting designs. Imaging was conducted using 3000, 6000, and 10,000pixel, miniature, flexible endoscopes with 0.4-, 0.6-, and 0.9-mm OD, to differentiate between urinary stones and ureter wall, for potential clinical application. The multichannel ureteroscope tip with 1.5-Fr working channel yielded a gravitational saline flow rate of 3.9 ± 0.2 mL / min compared to 31.3 ± 0.6 mL / min for standard (3.6Fr) ureteroscope channel. Manual, pump-assisted irrigation increased flow rate to 32.5 ± 3.0 mL / min. The 6000pixel, 0.6-mm OD, flexible endoscope provided a balance of clear differentiation between stones and ureter wall and sufficiently small OD. A ring lighting configuration provided more uniform illumination than conventional cross-lighting geometry as demonstrated by LIDCs. With further development, these miniature ureteroscope tip designs may be integrated into a fully functional ureteroscope to permit ureteral access with minimal trauma and improved patient safety and comfort.

Industrial Lighting: A Holistic Approach Using Light-Emitting Diode Technology

This article discusses the effects of implementing a specialized holistic lighting design throughout a new industrial petroleum-processing facility using highmast lights and the latest light-fixture technology rather than conventional lighting design methods. Topics of engineering justification for design decisions, the final design outcomes, and the financial impacts of choosing the design approach are presented in a case study, and additional environmental and economic successes and failures of the design philosophy are explored.

Thermal Design Calculations for LED Luminaires

Energy saving is one of the realities showed down human beings’ throat by rapidly wasting world resources in today’s world. In this context, nowadays LED armatures are replacing conventional lighting armatures as new generation lighting armatures. However, these innovations bring about new problems. While these innovations increase efficiency, they reveal the engineering problems that need to be solved. The most important problem is the thermal problems of LED armatures. In this study, the cooler size of the LED armature was calculated. In addition, a design prepared in ANSYS program was compared with its simulation and it was seen that the calculated cooler dimension gave successful results considering the simulation.