Metal Halide Light Sources Research Articles

An EEG based comparative study on driver's performance under the influence of metal halide and high pressure sodium lighting

For the last few decades the most favored light sources for road lighting designs are the Metal Halide (MH) and High Pressure sodium vapor (HPS). The use of LED has been increased profoundly in the recent time in different road lighting applications. One of the most important characteristics that differentiate both the light sources is their color. Although the spectral power density of both MH and HPS light sources contains peaks at different wavelengths throughout the visible spectrum but the color produced by the MH sources is mainly blue-white color and by the HPS sources are yellow. Recent study had shown that detection of object by the road users are highly influenced by lamp type (Biswas et al., 2018; Rea, 2013, 2014; Boyce Peter, 2014; Rea et al., 2010; Morante, n.d.). A comparative behavioral study along the performance analysis is thus very important from the driver’s point of view under the spectrum of these two light sources. In this research work the behavioral and detailed performance analysis study of a subject driving a vehicle in a simulated road lighting condition illuminated by HPS and MH light sources has been conducted. The driver’s time response along with electroencephalography (EEG) study was conducted to investigate the probable temporal processes and significant differences in the distribution of brain waves for detection of object located at on-axis (foveal). The results are compared for both the types of lamps and it has been found that metal halide lamps have better human cognitive performance.

The Impact of Retail Light Source on Greening of Russet Burbank Potato Tubers

The use of accent lighting in retail stores has focused illumination on potatoes for greater consumer awareness. Unfortunately, this directed light on displayed potatoes may impact the rate or level of tuber greening. The objective of this study was to evaluate the influence of various retail accent light sources on greening and quality of illuminated tubers. Two separate experiments exposed ‘Russet Burbank’ potato tubers to fiber optic, ceramic metal halide, fluorescent, fluorescent with filter lighting (experiment 1) and fiber optic, halogen, and fluorescent lighting (experiment 2). In each experiment, tubers were exposed to a consistent light intensity (1390 lx in experiment 1 and 1300 lx in experiment 2) in addition to a dark control. Tubers were illuminated for 22 h per day at an ambient room temperature of 22 C. Six randomly selected tubers were evaluated for level of greening, chlorophyll concentration, and weight loss at day 0, 2, 4, 7, and 9. Total glycoalkaloid content was analyzed at days 0 and 9. In experiment 1, the fiber optic and fluorescent illuminated tubers showed significantly lower chlorophyll content compared to the ceramic metal halide light source. There was no significant difference in chlorophyll level or greening rating between the fluorescent light source and fluorescent with filter. In experiment 2, the fiber optic illuminated tubers had lower chlorophyll content and less visual greening compared to the halogen illuminated tubers. Total glycoalkaloids were not significantly impacted by light source. The use of fiber optic lighting or a combination of fiber optic lighting with standard fluorescent lighting would retard the progression of greening in the retail store yet potentially highlight the commodity for consumer eye-appeal.

Effect of Artificial Light Conditions on Local and Systemic Resistance Response of Tobacco to TMV Infection

Systemic acquired resistance (SAR) is effectively inducible in greenhouse and certain artificial light sources cause non-optimal growth of tobacco plants. Therefore, the morphological characteristics, local and systemic resistance response of N. tabacum cv. ‘Xanthi’ nc plants (harbouring NN resistance genes) to tobacco mosaic virus (TMV) infection under three artificial light sources with different spectral distribution were compared with greenhouse conditions. Statistical analysis of data was carried out by R package (R Core Team, 2015). Generally, artificial light sources (especially fluorescent tube, and halogen lamp) decreased the local resistance response and caused substantial morphological and developmental differences as compared to greenhouse conditions when plants were kept during their entire life (lifelong experimental regime) under these conditions. On the contrary, no or much less differences were found when plants were transferred from greenhouse to artificial light sources only at six leaf stage (short experimental regime). While induction of systemic acquired resistance (SAR) frequently decreased TMV lesion size by about 50-60% under greenhouse conditions, two of the three artificial light sources, fluorescent tube and halogen lamp were substantially and significantly less effective under short experimental regime conditions (25-35%). A metal halide light source with similarity to sunshine’s spectral distribution, however, partially mimicked the effect of greenhouse conditions indicating the importance of light spectrum among other factors in SAR induction and prevention of distorted growth of plants. Consequently, the optimization of the effect of artificial light sources is an important factor in experimental design studying signal transduction and biochemistry of SAR.

Rapid and Early Detection of Salmonella Serotypes with Hyperspectral Microscopy and Multivariate Data Analysis

This study was designed to evaluate hyperspectral microscope images for early and rapid detection of Salmonella serotypes Enteritidis, Heidelberg, Infantis, Kentucky, and Typhimurium at incubation times of 6, 8, 10, 12, and 24 h. Images were collected by an acousto-optical tunable filter hyperspectral microscope imaging system with a metal halide light source measuring 89 contiguous wavelengths every 4 nm between 450 and 800 nm. Pearson correlation values were calculated for incubation times of 8, 10, and 12 h and compared with data for 24 h to evaluate the change in spectral signatures from bacterial cells over time. Regions of interest were analyzed at 30% of the pixels in an average cell size. Spectral data were preprocessed by applying a global data transformation algorithm and then subjected to principal component analysis (PCA). The Mahalanobis distance was calculated from PCA score plots for analyzing serotype cluster separation. Partial least-squares regression was applied for calibration and validation of the model, and soft independent modeling of class analogy was utilized to classify serotype clusters in the training set. Pearson correlation values indicate very similar spectral patterns for reduced incubation times ranging from 0.9869 to 0.9990. PCA score plots indicated cluster separation at all incubation times, with incubation time Mahalanobis distances of 2.146 to 27.071. Partial least-squares regression had a maximum root mean squared error of calibration of 0.0025 and a root mean squared error of validation of 0.0030. Soft independent modeling of class analogy correctly classified values at 8 h (98.32%), 10 h (96.67%), 12 h (88.33%), and 24 h (98.67%) with the optimal number of principal components (four or five). The results of this study suggest that Salmonella serotypes can be classified by applying a PCA to hyperspectral microscope imaging data from samples after only 8 h of incubation.

Research on LED Fishing Light

In this study , the semiconductor lighting technology with advantages of energy saving, environmental protection and high rapid response speed is regarded as the fishing light source, which can achieve targets of energy conservation, emission reduction, environmental protection, scientific fishing, etc. Then, the characteristics of LED are described to conduct a comparative analysis with the metal halide light source which has been commonly used in fishing light. The results show that LED is more suitable to be used as the fishing light source.

Acousto-Optic Tunable Filter Hyperspectral Microscope Imaging Method for Characterizing Spectra from Foodborne Pathogens

A hyperspectral microscope imaging (HMI) method, which provides both spatial and spectral information of bacterial cells, was developed for foodborne pathogen detection. The AOTF-based hyperspectral microscope imaging system can be effective for characterizing spectral properties of biofilms formed by Salmonella enteritidis as well as Escherichia coli. The intensity of spectral images and the pattern of intensity distribution of spectra varied with system parameters (integration time as well as gain) of the HMI system. Preliminary results demonstrated that determination of optimum parameter values of the HMI system and the integration time, which must be no more than 250 ms, are important for quality image acquisition from biofilms formed by S. enteritidis. Among the 89 contiguous spectral images between 450 and 800 nm, the intensity of images at 458, 494, 522, 550, 574, 590, and 670 nm were distinctive for biofilm of S. enteritidis, whereas the intensity of spectral images at 546 nm was distinctive for E. coli with dark-field illumination with a metal halide light source. For more accurate comparison of intensity from spectral images, a calibration protocol of quantitative intensity comparison needs to be developed to standardize image acquisition using neutral-density filters and multiple exposures. For the identification or classification of unknown foodborne pathogen samples, ground truth region-of-interest pixels need to be selected for spectrally pure fingerprints from various foodborne pathogens such as E. coli and Salmonella species.

ApoTome to visualize E‐cadherin and p63 expression in oral pre‐cancer

Precise histopathological localization of E-cadherin and p63 is of immense importance in understanding the integrity of oral mucosal stratified epithelium in normal and diseased conditions. Necessarily immunohistochemical imaging should have minimum bleaching impact on the dyes and ability to produce clear and crisp images. Here ApoTome provides an alternative with metal halide light source and structured illumination under the assistance of grids, along with integrated image processing modality to generate crisp images with digital interface. The current study demonstrates the applicability of such microscopic system in capturing fluorescence images of immunohistochemical sections of normal and precancerous biopsies in respect to the expression of p63 and E-cadherin in the epithelial cells. The ApoTome images localize the nuclear and membranous expressions of p63 and E-cadherin, respectively, with remarkable specificity. The findings on E-cadherin expression have enormous diagnostic significance as these images clearly differentiate the early and advanced stages of oral submucous fibrosis based on their cytoplasmic and membranous location. Thus, this study clearly depicts a remarkable performance of ApoTome with diagnostic significance.

Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

The brainstem contains rhythm and pattern forming circuits, which drive cranial and spinal motor pools to produce respiratory and other motor patterns. Here we used calcium imaging combined with nerve recordings in newborn mice to reveal spontaneous population activity in the ventral brainstem and in the facial nucleus. In Fluo-8AM loaded brainstem-spinal cord preparations, respiratory activity on cervical nerves was synchronized with calcium signals at the ventrolateral brainstem surface. Individual ventrolateral neurons at the level of the parafacial respiratory group showed perfect or partial synchrony with respiratory nerve bursts. In brainstem-spinal cord preparations, cut at the level of the mid-facial nucleus, calcium signals were recorded in the dorsal, lateral and medial facial subnuclei during respiratory activity. Strong activity initiated in the dorsal subnucleus, followed by activity in lateral and medial subnuclei. Whole-cell recordings from facial motoneurons showed weak respiratory drives, and electrical field potential recordings confirmed respiratory drive to particularly the dorsal and lateral subnuclei. Putative facial premotoneurons showed respiratory-related calcium signals, and were predominantly located dorsomedial to the facial nucleus. A novel motor activity on facial, cervical and thoracic nerves was synchronized with calcium signals at the ventromedial brainstem extending from the level of the facial nucleus to the medulla–spinal cord border. Cervical dorsal root stimulation induced similar ventromedial activity. The medial facial subnucleus showed calcium signals synchronized with this novel motor activity on cervical nerves, and cervical dorsal root stimulation induced similar medial facial subnucleus activity. In conclusion, the dorsal and lateral facial subnuclei are strongly respiratory-modulated, and the brainstem contains a novel pattern forming circuit that drives the medial facial subnucleus and cervical motor pools.

SAFETY TESTING OF INDOCYANINE GREEN WITH DIFFERENT SURGICAL LIGHT SOURCES AND THE PROTECTIVE EFFECT OF OPTICAL FILTERS

The purpose of this study was to assess the light-induced cytotoxicity of indocyanine green (ICG) using different light sources commonly used in macular surgery and to assess the effect of optical filters. Primary cultures of porcine retinal pigment epithelium cells were incubated with 0.5 mg/mL ICG solution dissolved in 5% glucose and illuminated with a surgical light fiber for 3 or 15 minutes. Halogen, mercury vapor, xenon, and metal halide light sources were used. Cell viability was assessed using the MTT assay. Retinal pigment epithelium cells without illumination served as controls. The decomposition of ICG after illumination was analyzed by high-performance liquid chromatography. Illumination of retinal pigment epithelium cells with all light sources with or without previous incubation with ICG did not affect cell viability compared with controls. Cell viability was significantly reduced when the cells were not rinsed immediately after incubation. The cytotoxic effect was abolished by a 475-nm long-pass filter. The high-performance liquid chromatography analysis of the illuminated ICG solution identified six cytotoxic ICG decomposition products. Optical filters that narrow the emission spectrum of the light sources reduce the light-induced cytotoxicity of ICG. Optical filters applied in ICG-assisted macular surgery may reduce the risk of intraoperative cell damage.

A study on the macroscopic spray behavior and atomization characteristics of biodiesel and dimethyl ether sprays under increased ambient pressure

Abstract The aim of this work is to investigate the spray behaviors of biodiesel and dimethyl ether (DME) fuels using image processing and atomization performance analysis of the two fuel sprays injected through a common-rail injection system under various ambient pressure conditions in a high pressure chamber. In order to observe the biodiesel and DME fuel spray behaviors under various ambient pressures, the spray images were analyzed at various times after the start of energization using a visualization system consisting of a high speed camera and two metal halide light sources. In addition, a high pressure chamber that can withstand a pressure of 4 MPa was used for adjusting the ambient pressure. From the spray images, spray characteristics such as the spray tip penetration, cone angle, area, and contour plot at various light intensity levels were analyzed using image conversion processing. Also, the local Sauter mean diameters (SMD) were measured at various axial/radial distances from the nozzle tip by a droplet measuring system to compare the atomization performances of the biodiesel and DME sprays. The results showed that the ambient pressure had a significant effect on the spray characteristics of the fuels at the various experimental conditions. The spray tip penetration and spray area decreased as the ambient pressure increased. The contour plot of the biodiesel and DME sprays showed a high light intensity level in the center regions of the sprays. In addition, it was revealed that the atomization performance of the biodiesel spray was inferior to that of the DME spray at the same injection and ambient conditions.

Dye-sensitized solar cell based on Rose Bengal dye and nanocrystalline TiO 2

Dye-sensitized solar cell is fabricated using Rose Bengal dye (RB) for sensitization of nanocrystalline TiO 2 and that imparts extension in spectral response towards visible region by modifying the semiconductor surface. Further, the photoresponse of the cell was evaluated by analyzing its J– V and impedance characteristics under illumination with metal halide light source of 400 W with an incident light of 73 mW/cm 2. Various photovoltaic parameters like J sc, V oc, FF were evaluated and found to be 3.22 mA, 890 mV, 0.53, respectively, resulting conversion efficiency ( η) of 2.09%. Impedance analysis of the cell was carried out to investigate the internal resistance of the cell by recording Cole–Cole plots in between real and imaginary impedance in dark and with illumination under variable biasing, i.e. from 0 to 3 V.

Relation between the illuminance responsivity of a photometer and the spectral power distribution of a source

The illuminance responsivity dependencies on spectral power distributions (SPDs) of different types of light sources are studied. In this work we used three types of calibrated photometers, one of which was home-made and two were commercial photometers. A monochromator-based facility was used to scan SPDs of light sources. The dependencies of spectral mismatch correction factors F(S t ,S s ) and the illuminance responsivities of photometers versus the SPDs of tungsten-filament incandescent, fluorescent, high-pressure sodium, and metal-halide light sources and white/colored light-emitting diodes are presented throughout this work.

Driver decision making in response to peripheral moving targets under mesopic light levels

A field study was conducted to extend fundamental findings about visual performance at mesopic light levels to a driving context. Subjects participating in this field study drove a vehicle along a lighted street while performing a high-order decision-making task. Subjects identified the direction of an off-axis target, toward or away from the street, and braked or accelerated, accordingly. Two sets of light sources were compared: a set of ceramic metal halide light sources and a set of high-pressure sodium light sources. The same study was also performed during the day-time. The results demonstrated that both braking and acceleration response times decreased monotonically as unified luminance increased, suggesting that unified luminance is a suitable rectifying variable for characterizing light levels for different light sources with respect to a complex visual task.

A New Laboratory Polymerizing Apparatus Equipped with Halogen and Metal Halide Light Sources

We developed a new laboratory polymerizing unit (Twinkle MIII: M3) equipped with different light sources (a metal halide and two halogen lamps) that could illuminate independently. This study introduced the structure of the curing unit and examined the curing depth of a representative indirect composite (Artglass). The composite material was cured with the following modes: 1) M3 - halogen only; 2) M3 - metal halide only; 3) M3 - both halogen and metal halide (HM); 4) conventional xenon; and 5) preliminary halogen. The results obtained from analysis of variances and post-hoc tests revealed that curing depth was affected significantly (p < 0.05) by both exposure mode and time, and that HM mode exhibited the most favorable curing performance (p < 0.05) among the curing units and polymerization modes. In conclusion, the M3 unit was found to be well suited to polymerizing the composite material tested.

Effect of metal halide light source on hardness, water sorption and solubility of indirect composite material

This study evaluates the effects of a metal halide light source on the post-polymerization properties of the Sinfony indirect composite material. Two polymerization systems were employed: the Hyper LII system, comprising a metal halide polymerization unit, and the Visio system, comprising two proprietary units designed for polymerizing the Sinfony composite. The composite material was polymerized for 60, 120 or 180 s with the LII system. As a control, the composite was polymerized for 15 min with the Visio system. Knoop hardness, water sorption and solubility were determined. The results were analyzed by Dunnett's T3 multiple comparison test (P<0.05). Knoop hardness was greater for polymerization with the LII unit than for that with the Visio system. Water sorption was greater for polymerization with the Visio system than that with the LII unit. For polymerization with the LII unit for 180 s, solubility was significantly reduced as compared with the Visio system. Within the limitations of the current experiment, it can be concluded that the metal halide unit exhibited better polymerizing performance for the composite material than the proprietary units.

Frankfurters — acceptability under different retail lights

Dark, medium, and light colour frankfurters (no-fat, low-fat, and regular fat level) were evaluated by panellists under incandescent (INC), fluorescent (FL), and metal halide (MH) light sources. INC illumination resulted in a higher colour preference (P &lt; 0.05) for the medium and light products over that of the FL and MH illuminations; no significant difference was seen between FL and MH lighting. The panellists described the medium coloured frankfurters as pink under INC lighting, but more brown under FL and MH illumination. Relative luminance data, collected via a fibre optic probe connected to a photo diode array, demonstrated the reason to be the low red colour seen by the panellists under FL and MH light sources. For the dark colour frankfurters, there was no difference in colour preference scores among the three illumination sources. Key words: Colour, fat, frankfurters, light, meat, sausage, sensory, spectra

Effect of three commercial light sources on acceptability of Salmon, Snapper and Sea Bass fillets

The effects of incandescent (INC), fluorescent (FL), and metal halide (MH) light sources on the acceptance of Salmon, Snapper and Sea Bass fillets were investigated. The color of the Salmon and Snapper was most preferred ( P<0.05) under INC light, as compared to FL and MH. Positive buying response was also significantly higher under INC as compared to FL and MH. Under INC light, salmon was described as dark and medium orange, but mainly light and medium orange under FL and MH. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, showed that there was a low red and orange reflection from the fillets placed under FL and MH light sources. The Sea Bass was equally preferred under the three light sources due to its white/cream color.

Dynamic Deformation Capability of A Red Blood Cell under A Cyclically Reciprocating Shear Stress

Red blood cells (RBCs) in the cardiovascular devices are exposed to varying degree of the shear stress from all the directions. However the RBCs' deformability or the deformation capability under such a shear stress is not well understood. In this study, we designed and built a system that can induce a cyclically reciprocating shear stress to a RBC suspension. The arm of the cyclically reciprocating shear stress device was attached to the upper piece of the parallel glass plates between which a suspension of human RBCs (1% hematocrit whole blood diluted in a 32 weight% dextran phosphate buffer solution) was contained. The cyclic reciprocating motion of the upper glass plate of 3.0 mm stroke length was produced using a slider-crank shaft mechanism that was linked to an eccentric cam-motor system. Each rotation of the motor produced a 3.0 mm stroke each in the forward and backward direction of the slider block. The clearance between the two glass plates was adjusted to 30 micrometer. The cyclic reciprocating glass plate apparatus was attached to a light microscope stage (IX71 Olympus with x40 objective lens) for illumination with a 350 watt metal halide light source. A high speed camera (MEMREMCAM fx-K3 Nac, 5000 frames per second with shutter kept open) was attached to the microscope to capture the deformation process of the RBCs under cyclic shear stress. The preliminary result indicated that the correlation between the amplitude of the maximum shear stress and the RBCs' deformability. This indicates a potential application of the cyclic reciprocating device to evaluate the temporal response of the RBCs deformability prior to its destruction. The future study will focus on the study of the relative velocity of the erythrocytes with respect to the velocity of the reciprocating plate.

DISPLAY LIGHT AND ACCEPTABILITY OF GREEN, RED AND YELLOW PEPPERS

The effects of incandescent (INC), fluorescent (FL), and metal halide (MH) light sources on the appearance of red, green, and yellow sweet bell peppers were investigated. The color of the red pepper was significantly preferred when presented under INC than under FL and MH lights. The term used by the panelists to describe the color of peppers under INC light was mainly bright red, but dark red under FL and MH. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, demonstrated the reason to be the low red light output from the FL and MH sources, which resulted in a low visible red color. The color of the green pepper was more acceptable under INC than under MH. For the yellow pepper, there was no significant effect of the light source because all three light bulbs emit a strong yellow component.

Effect of lighting on ground beef acceptability

The effects of incandescent (INC), cool-white fluorescent (FL), and metal halide (MH) light sources on the appearance of medium, lean, and extra lean ground beef meat were investigated. Meat color with INC illumination was preferred (P &lt; 0.05) over that with MH illumination for all meat types, and over FL illumination for extra-lean and medium meats. The majority of the panelists described the meat as red under INC lighting, but brown or dark red under FL and MH lighting. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, demonstrated the reason to be a lack of redness in the FL and MH light sources. Key words: Acceptability, beef, color, hamburger, meat, spectra, sensory