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

Electricity is an essential need for humans, specifically for the lighting function. Lighting is needed to aid humans visually perceive objects in areas that require lighting, both at night and during the day. At this day, there are two type of lamps that are extensively employed, paticularly the type of Light-Emitting Diode (LED) and Compact Fluorescent Lamp (CFL). The adoption of lights in an area takes a lot of energy, so it is particularly crucial to choose the appropriate type of lamp that is adequate to perform effectively and efficiently. To determine the light distribution of the two types of lights, it is crucial to investigate the distribution of light. The investigation was carried out by the direct measurement technique on 6 and 8 watt LED lamps, as well as on CFL lamps 11 and 14 watt using luxmeter in an area projecting 3×4 meters. The analysis range is varied in several horizontal and vertical points. From the assessment results it was noticed that the LED and CFL lamps the value of the light intensity reduces if the horizontal and vertical distance of the measurement point are far from the lamp. The ends of the light distribution mapping discovered that the light distribution on the LED lights is better indeed and brighter at each point. This is because all the electrons recombine with holes. Whereas in the CFL lamp there has been a filament heating and ionization between the electrons with argon gas and mercury vapor which generates another energy which is relatively large heat energy.

The use of light in some types of fisheries has been one of the most advanced and successful methods to control fish for capture purposes. The use of electrical lamps has been developed as a method of attracting small pelagic fish in Indonesia. Fixed lift nets (bagan tancap) are a fishing gear type categorized as lift nets with fine meshed (0.5 cm mesh size) box-shaped netting, operated using lamps to attract pelagic fish. Several studies on fixed lift nets (bagan) were conducted in Makassar Strait, South Sulawesi, Indonesia from 2012-2017. These studies used various types of electric lamps, such as halogen lamps, mercury lamps, incandescent lamps and light emitting diodes (LEDs). The fishing process was analysed through on-board observation during fishing operations and interviews with fixed lift net fishermen. The results showed that small pelagic fish species tended to prefer the halogen (neon) lamps compare to mercury and incandescent lamps, as they were more effective in attracting small pelagic species to fixed lift nets in the coastal area. A new type of lamp considered more environmentally friendly, the light emitting diode (LED), was also introduced on fixed lift nets. The result of the research on introducing light emitting diodes (LEDs) in fixed lift nets is discussed.

Photocatalytic reduction of Cr(VI) by PVA-alginate encapsulated γFe2O3 magnetic beads using different types of illumination lamp and light

Purpose An indoor office space should not only provide adequate illuminance on horizontal planes but also cater to the physiological and psychological requirements of the occupants. This paper aims to describe a lighting simulation-based work conducted in Kolkata, India which modeled an indoor office to investigate the effects of variation in room surface reflectance combinations on user perception, mean room surface exitance (MRSE), average horizontal illuminance and overall uniformity of horizontal illuminance. Design/methodology/approach A fluorescent illumination system–based office space was modeled and retrofitted with tubular LED lamps in DIALux. Simulations were conducted for 16 different room surface reflectance combinations and a five-point Likert scale-type survey questionnaire was formulated to conduct a survey with 32 test subjects to assess the subjective preferability of each resultant light scene. Findings Simulation results demonstrate that the relationship between average horizontal illuminance and MRSE as well as between average horizontal illuminance and overall uniformity of horizontal illuminance, was statistically significant (p < 0.001). In the conducted survey, the resultant light scene arising out of the reflectance combination of wall:ceiling:floor = 60%:90%:20% was the most well-received one with 187 convinced agreements (“agree” and “strongly agree” responses). Originality/value This work found strong linear correlation between average horizontal illuminance and MRSE and between average horizontal illuminance and overall uniformity. A five-point Likert scale-type survey questionnaire with seven questions was formulated and validated with 32 test subjects (Cronbach’s alpha > 0.9295), which showed that the wall:ceiling:floor reflectance combination of 60%:90%:20% was the most favored choice.

Optimisation of supplemental light systems in Norwegian tomato greenhouses - A simulation study

BackgroundResearch has indicated that the environment may play an important role in the transmission of meticillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile in healthcare facilities. Despite the significance of this finding, few data exist from longitudinal studies investigating MRSA and C. difficile contamination, concurrently, in both patient rooms and the general ward environment. The objectives of this study were to determine the prevalence of MRSA and C. difficile contamination in patient rooms and the ward environment and identify risk factors associated with a surface being contaminated with these pathogens.MethodsEnvironmental surfaces in patient rooms and the general environment in the medical and surgical wards of a community hospital were sampled six times over a 15 week period. Sterile electrostatic cloths were used for sampling and information pertaining to the surface sampled was recorded. MRSA isolates and C. difficile specimens were obtained from hospitalized patients.Enrichment culture was performed and spa typing or ribotyping was conducted for MRSA or C. difficile, respectively. Exact logistic regression models were constructed to examine risk factors associated with MRSA and C. difficile contamination.ResultsSixteen (41%) patient rooms had ≥ 1 surfaces contaminated with MRSA and/or C. difficile. For 218 surfaces investigated, 3.2% and 6.4% were contaminated with MRSA or C. difficile, respectively. Regression models indicated that surfaces in rooms exposed to a C. difficile patient had significantly increased odds of being contaminated with C. difficile, compared to surfaces in unexposed patient rooms. Additionally, compared to plastic surfaces, cork surfaces had significantly increased odds of being contaminated with C. difficile. For 236 samples collected from the ward environment, MRSA and C. difficile were recovered from 2.5% and 5.9% of samples, respectively. Overall, the majority of MRSA and C. difficile strains were molecularly identified as spa type 2/t002 (84.6%, n = 11) and ribotype 078 (50%, n = 14), respectively.ConclusionsIn patient rooms and the ward environment, specific materials and locations were identified as being contaminated with MRSA or C. difficile. These sites should be cleaned and disinfected with increased vigilance to help limit the transmission and dissemination of MRSA and C. difficile within the hospital.

Based on available literature, ecology and economy of light emitting diode (LED) lights in plant foods production were assessed and compared to high pressure sodium (HPS) and compact fluorescent light (CFL) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco-friendly lighting devices. The present review indicates also that LEDs have many practical benefits compared to other lamp types. In addition, they are applicable in many purposes in plant foods production. The main focus of the review is the targeted use of LEDs in order to enrich phytochemicals in plants. This is an expedient to massive improvement in production efficiency, since it diminishes the number of plants per phytochemical unit. Consequently, any other production costs (e.g. growing space, water, nutrient and transport) may be reduced markedly. Finally, 24 research articles published between 2013 and 2017 were reviewed for targeted use of LEDs in the specific, i.e. blue range (400-500 nm) of spectrum. The articles indicate that blue light is efficient in enhancing the accumulation of health beneficial phytochemicals in various species. The finding is important for global food production. © 2017 Society of Chemical Industry.

Hyperspectral imaging has shown great promise for diagnostic applications, particularly in cancer surgery. However, non-bulk tissue-related spectral variations complicate the data analysis. Common techniques, such as standard normal variate normalization, often lead to a loss of amplitude and scattering information. This study investigates a novel approach to address these spectral variations in hyperspectral images of optical phantoms and excised human breast tissue. Our method separates surface and volume reflectance, hypothesizing that spectral variability arises from significant variations in surface reflectance across pixels. An illumination setup was developed to measure samples with a hyperspectral camera from different axial positions but with identical zenith angles. This configuration, combined with a novel data analysis approach, allows for the estimation and separation of surface reflectance for each direction and volume reflectance across all directions. Validated with optical phantoms, our method achieved an 83% reduction in spectral variability. Its functionality was further demonstrated in excised human breast tissue. Our method effectively addresses variations caused by surface reflectance or glare while conserving surface reflectance information, which may enhance sample analysis and evaluation. It benefits samples with unknown refractive index spectra and can be easily adapted and applied across a wide range of fields where hyperspectral imaging is used.

This study was undertaken to evaluate performance of three models of horizontal and two models of vertical illuminance based on measured data in Iran. Measurement of horizontal and South oriented vertical illuminance was carried out at three stations of Eshtehard, Hamadan and Kerman over 15 days at one hour intervals between 12 July and 1 August 2007 from 9 a.m. to 3 p.m. Synchronically calculation of solar altitudes and global horizontal illuminance carried out utilizing equations proposed by Illuminating Engineering Society of North America (IESNA) for measuring period. Two localized models entitled Solar altitude model and IESNA model in conjunction with the model of Robledo was adopted to predict horizontal illuminance. Also for predicting of South oriented vertical illuminance, a localized model based on IESNA equations in conjunction with a model of Ruiz were taken in to account. Mean measured and predicted horizontal values by three models found to be 96 KLx and 107.3-108.7 KLx, respectively. Among three horizontal models the model of IESNA (MBD = -1.26, RMSD = 10.25) performed best and the model of solar altitude performed worst. Mean measured and predicted values of vertical illuminance by two vertical models found to be 33.59 and 25.71-32.19, respectively. The IESNA model (MBD = -1.4, RMSD = 0.2) performed better than the model of Ruiz. Respective mean monthly predicted horizontal and vertical illuminance exceeded 63 KLx for 50 and 0.96% of working year indicating high daylight availability on horizontal and vertical planes in Iran.

A psychophysical experiment was conducted to investigate brightness perception and color preference under illumination from typical 3000 K blue-pumped light emitting diode (LED) A19 lamps (BP-LED) and 3000 K blue-pumped LED A19 lamps with diminished yellow emission (YD-LED). Eighty-seven participants between 19 and 25 years completed brightness matching and preference comparisons between two full-size side-by-side rooms that contained chromatic objects and still life arrangements, with one lamp type in each room. Participants had higher overall preference to the room illuminated by YD-LED. Specifically, red, green, orange, and wood objects were preferred under YD-LED; no preference was found for neutral, yellow, and blue objects between the two lamp types. The words saturated, vivid, vibrant, pleasant, inviting, colorful, stand-out, distinct, appealing, and comfortable were reported as reasons for the color preference under YD-LED; dull, dead, and fade were used by participants to describe the lower color preference under BP-LED. Skin tone preference under the illumination of these two lamp types was significantly different between Asian (n = 32) and Caucasian (n = 52) participants. Caucasians evaluated their own skin tone more favorably under YD-LED, with the average assessment that skin appeared healthy and colorful under YD-LED but grey and pale under BP-LED. No preference between the two lamps was found among Asians for their skin tone, though some Asians thought YD-LED rendered their skin too red and odd. Many existing measures of color preference and gamut were able to predict the higher overall preference to YD-LED, but they could not predict the preference of specific colors or for ethnic groups. The higher saturation and preference for red and green colors under YD-LED illumination is consistent with the higher red–green opponent signal provided by YD-LED. Coupled with several past studies, the spectral region around 570–580 nm appears to be deleterious to color and brightness perception.

ABSTRACTThis study investigates the ability of artificial intelligence (AI) to simulate human emotional responses to color using two established methods: semantic differential (SD) method and word‐color association (WCA) approach. The SD method quantifies emotional reactions to colors through bipolar adjective pairs (e.g., warm–cool, heavy–light), while the WCA method explores associations between specific words and colors. AI responses were compared with data from human participants across various demographics. Results show that AI consistently evaluates basic emotional dimensions, such as warm–cool and heavy–light, with high accuracy, often surpassing human consistency. However, AI struggled with more subjective and culturally influenced dimensions like modern–classical and active‐passive. In the WCA experiment, AI replicated many general color associations but faced challenges with complex emotions like joy and anticipation. These findings highlight AI's potential in tasks requiring standardized emotional responses but reveal its limitations in capturing nuanced human emotions, especially in culturally sensitive contexts.

When natural days are short, photoperiodic lighting at the end or beginning of the day (day extension) or in the middle of the night (night break) promotes flowering of long-day plants. The objective of this study was to compare broad-spectrum warm-white light-emitting diodes (LEDs) and red (R) + far-red (FR) LEDs at flowering regulation when delivered at different timings in the night period. We performed a greenhouse experiment on four long-day ornamentals [coreopsis ( Coreopsis grandiflora ) ‘Early Sunrise’, snapdragon ( Antirrhinum majus ) ‘Liberty Classic Yellow’, petunia ( Petunia × hybrida ) ‘Easy Wave Burgundy Star’, and petunia ‘Wave Purple Improved’]. We grew plants under a truncated 8-hour photoperiod with or without low-intensity (∼2 μmol·m −2 ·s −1 ) nighttime lighting from warm-white or R+FR LEDs. For each light quality, we delivered four timings: 1) 8 hours after dusk; 2) 8 hours before dawn; 3) 4 hours after dusk + 4 hours before dawn; and 4) 4-hour night break. The effectiveness of floral promotion was determined by time from the treatment onset to the first open flower. Coreopsis flowered similarly under all lighting treatments, irrespective of light quality and timing, but did not flower under the short-day treatment by the end of the experiment. At flowering, coreopsis was 18% to 19% shorter under white than R+FR LEDs. In contrast, snapdragon flowered 9 to 20 days later under white than R+FR LEDs, when delivered for 8 hours at night, but flowered similarly under these two lamp types as a 4-hour night break. Compared with the short-day treatment, white and R+FR LEDs promoted flowering of both petunia cultivars, although flowering generally occurred later under white than R+FR LEDs. Snapdragon and petunia ‘Easy Wave Burgundy Star’ developed 30% to 122% more lateral branches under white than R+FR LEDs, when delivered for 8 hours at night. The effectiveness of warm-white LEDs was generally unaffected by timing, although it was most promotive of flowering in snapdragon when delivered for 8 hours before dawn. For R+FR LEDs, 8-hour day-extension lighting was generally more effective than 4-hour night-break lighting, irrespective of timing. We conclude when delivered for 8 hours at night, warm-white LEDs are generally less effective than R+FR LEDs at promoting flowering of long-day ornamentals but similarly effective as 4-hour night-break lighting. The effectiveness of day-extension lighting is generally independent of timing, although for R+FR LEDs, 8 hours after-dusk and/or before-dawn lighting was generally more effective than 4-hour night-break lighting.

Light-emitting diode (LED) lighting has, compared to other types of lighting, a significantly lower energy consumption. However, the perceived service life is also important for customer satisfaction and here there is a discrepancy between customers’ experience and manufacturers’ statements. Many customers experience a significantly shorter service life than claimed by the manufacturers. An experiment was carried out in the Pehr Högström Laboratory at Luleå University of Technology in Skellefteå, Sweden to investigate whether voltage disturbances could explain this discrepancy. Over 1000 LED lamps were exposed to high levels of voltage disturbances for more than 6000 h; the failure rate from this experiment was similar to the one from previous experiments in which lamps were exposed to normal voltage. The discrepancy thus remains, even though some possible explanations have emerged from the project’s results. The lamps were exposed to five different types of voltage disturbances: short interruptions; transients; overvoltage; undervoltage; and harmonics. Only overvoltage resulted in failure of the lamps, and only for a single topology of lamp. A detailed analysis has been made of the topology of lamps that failed. This lamp type contains a different internal electronics circuit than the other lamp types. Failures of the lamps when exposed to overvoltage are due to the heat development in the control circuit increasing sharply when the lamps are exposed to a higher voltage. Hence, it is concluded that there are lamps that are significantly more sensitive to voltage disturbances than other lamp types. Manufactures need to consider the voltage quality that can be expected at the terminal of the lamp to prevent failure of lamps due to voltage disturbances. This paper therefore contains recommendations for manufacturers of lighting; the recommendations describe which voltage disturbances lamps should cope with.

The aim of the study was to evaluate the influence of different light sources on organ characteristics, bone development, chemical body composition and hepatic function of female Japanese quail (Coturnix coturnix japonica) in different reproductive ages. In total, 210 female 1-day-old birds were housed in a brick shed, which was divided into six rooms during 12 weeks. Each room was equipped with a different type of light bulb (incandescent; compact fluorescent; and white, blue, red and green light-emitting diodes (LEDs)) and contained seven cages with five birds in each. The light intensity was 15 lx and the photoperiod was 23 h light and 1 h dark (23L:1D) during the first week, 10 L:14D from the second to the fifth week, and 17L:7D until the end of the experiment. The experimental design was completely randomised, with six treatments and seven replicates of each bird. The morphophysiological conditions of the birds were evaluated at the beginning (8 weeks) and during peak production (12 weeks). At 8 weeks, a higher intestine weight and length and liver weight were observed in birds maintained in white LED (P < 0.05). Lower breast weight (P < 0.01) was also observed with this type of lamp. White and red LEDs decreased (P < 0.05) the percentage of ash in the tibia, but this reduction did not affect (P > 0.05) bone resistance. At 12 weeks, higher bone resistance was obtained (P < 0.01) with white LED and higher eye diameter was observed (P < 0.05) with incandescent and white LED lamps. There was no influence (P > 0.05) of light sources on the circulating levels of aspartate aminotransferase and alanine aminotransferase. Fluorescent bulbs resulted in the highest (P < 0.05) level of γ-glutamyltransferase, while blue LED resulted in the lowest level. There was no influence (P > 0.05) of light sources on chemical body composition in any of the evaluated ages. It was concluded that the photostimulation of Japanese quail with white LED is more efficient to stimulate their organ development, especially the intestine, until 8 weeks of life, resulting in birds with better bone development during peak production.

This report covers the third part of a larger U.S. Department of Energy (DOE) project to assess the life-cycle environmental and resource impacts in the manufacturing, transport, use, and disposal of light-emitting diode (LED) lighting products in relation to incumbent lighting technologies. All three reports are available on the DOE website (www.ssl.energy.gov/tech_reports.html). • Part 1: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps; • Part 2: LED Manufacturing and Performance; • Part 3: LED Environmental Testing. Parts 1 and 2 were published in February and June 2012, respectively. The Part 1 report included a summary of the life-cycle assessment (LCA) process and methodology, provided a literature review of more than 25 existing LCA studies of various lamp types, and performed a meta-analysis comparing LED lamps with incandescent and compact fluorescent lamps (CFLs). Drawing from the Part 1 findings, Part 2 performed a more detailed assessment of the LED manufacturing process and used these findings to provide a comparative LCA taking into consideration a wider range of environmental impacts. Both reports concluded that the life-cycle environmental impact of a given lamp is dominated by the energy used during lamp operation—the upstream generation of electricity drives the total environmental footprint of the product. However, a more detailed understanding of end-of-life disposal considerations for LED products has become increasingly important as their installation base has grown. The Part 3 study (reported herein) was undertaken to augment the LCA findings with chemical analysis of a variety of LED, CFL, and incandescent lamps using standard testing procedures. A total of 22 samples, representing 11 different models, were tested to determine whether any of 17 elements were present at levels exceeding California or Federal regulatory thresholds for hazardous waste. Key findings include: • The selected models were generally found to be below thresholds for Federally regulated elements; • All CFLs and LED lamps and most incandescent lamps exceeded California thresholds for Copper; • Most CFL samples exceeded California thresholds for Antimony and Nickel, and half of the LED samples exceeded California thresholds for Zinc; • The greatest contributors were the screw bases, drivers, ballasts, and wires or filaments; • Overall concentrations in LED lamps were comparable to cell phones and other types of electronic devices, and were generally attributable to components other than the internal LED light sources; • Although the life-cycle environmental impact of the LED lamps is favorable when compared to CFLs and incandescent lamps, recycling will likely gain importance as consumer adoption increases. This study was exploratory in nature and was not intended to provide a definitive indication of regulatory compliance for any specific lamp model or technology. Further study would be needed to more broadly characterize the various light source technologies; to more accurately and precisely characterize a specific model; or to determine whether product redesign would be appropriate.