Note: A portable, light-emitting diode-based ruby fluorescence spectrometer for high-pressure calibration

2011 ◽  
Vol 82 (4) ◽  
pp. 046105 ◽  
Author(s):  
Yejun Feng
Keyword(s):  
High Pressure ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Pressure Calibration ◽  
Fluorescence Spectrometer

Silicon-based light emitting diode material studied under high pressure

2004 ◽  
Vol 241 (14) ◽  
pp. 3387-3390 ◽  
Author(s):  
A. D. Prins ◽  
Y. Ishibashi ◽  
S. Sasahara ◽  
J. Nakahara ◽  
M. A. Lourenco ◽  
...  
Keyword(s):  
High Pressure ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Silicon Based

scholarly journals Light-emitting Diodes Can Replace High-pressure Sodium Lighting for Cut Gerbera Production

HortScience ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Dave Llewellyn ◽  
Katherine Schiestel ◽  
Youbin Zheng
Keyword(s):  
High Pressure ◽  
Treatment Effects ◽  
Light Emitting Diode ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Vase Life ◽  
Light Emitting ◽  
Greenhouse Study ◽  
Flower Diameter

A greenhouse study was undertaken to investigate whether light-emitting diode (LED) technology can be used to replace high-pressure sodium (HPS) lighting for cut gerbera production during Canada’s traditional supplemental lighting (SL) season (November to March). The study was carried out at the University of Guelph’s research greenhouse, using concurrent replications of SL treatments within the same growing environment. LED (85% red, 15% blue) and HPS treatment plots were set up to provide equal amounts of supplemental photosynthetically active radiation (PAR) at bench level. This setup was used to assess the production of three cultivars of cut gerbera (Gerbera jamesonii H. Bolus ex Hook.f): Acapulco, Heatwave, and Terra Saffier. There were no treatment differences in SL intensity, with average SL photosynthetic photon flux density (PPFD) and daily light integral (DLI) of 55.9 µmol·m−2·s−1 and 2.3 mol·m−2·d−1, respectively. Flowers harvested from the LED treatment had a 1.9% larger flower diameter in ‘Acapulco’; 4.2% shorter and 3.8% longer stems in ‘Heatwave’ and ‘Terra Saffier’, respectively; and 7.7% and 8.6% higher fresh weights for ‘Acapulco’ and ‘Terra Saffier’, respectively, compared with flowers harvested from the HPS treatment. There were no differences in accumulated total or marketable flower harvests for any of the cultivars. The vase life of ‘Acapulco’ flowers grown under the LED treatment was 2.7 d longer than those grown under the HPS treatment, but there were no SL treatment effects on water uptake for any of the cultivars during the vase life trials. There were no SL treatment effects on specific leaf area for any of the cultivars. There were only minimal treatment differences in leaf, soil, and air temperatures. Cut gerbera crops grown with under LED SL had equivalent or better production and crop quality metrics compared with crops grown under HPS SL.

scholarly journals Comparison of Intracanopy Light-emitting Diode Towers and Overhead High-pressure Sodium Lamps for Supplemental Lighting of Greenhouse-grown Tomatoes

2013 ◽  
Vol 23 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Celina Gómez ◽  
Robert C. Morrow ◽  
C. Michael Bourget ◽  
Gioia D. Massa ◽  
Cary A. Mitchell
Keyword(s):  
High Pressure ◽  
Energy Consumption ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Significant Proportion ◽  
Fruit Production ◽  
Light Sources ◽  
Node Number ◽  
Light Emitting ◽  
Supplemental Lighting

Electric supplemental lighting can account for a significant proportion of total greenhouse energy costs. Thus, the objectives of this study were to compare high-wire tomato (Solanum lycopersicum) production with and without supplemental lighting and to evaluate two different lighting positions + light sources [traditional high-pressure sodium (HPS) overhead lighting (OHL) lamps vs. light-emitting diode (LED) intracanopy lighting (ICL) towers] on several production and energy-consumption parameters for two commercial tomato cultivars. Results indicated that regardless of the lighting position + source, supplemental lighting induced early fruit production and increased node number, fruit number (FN), and total fruit fresh weight (FW) for both cultivars compared with unsupplemented controls for a winter-to-summer production period. Furthermore, no productivity differences were measured between the two supplemental lighting treatments. The energy-consumption metrics indicated that the electrical conversion efficiency for light-emitting intracanopy lighting (LED-ICL) into fruit biomass was 75% higher than that for HPS-OHL. Thus, the lighting cost per average fruit grown under the HPS-OHL lamps was 403% more than that of using LED-ICL towers. Although no increase in yield was measured using LED-ICL, significant energy savings for lighting occurred without compromising fruit yield.

Development of a High-Pressure, High-Temperature, Optically Accessible Continuous-Flow Vessel for Fuel-Injection Experiments

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Kemar C. James ◽  
Jin Wang ◽  
Michael C. Maynard ◽  
Zackery B. Morris ◽  
Brian T. Fisher
Keyword(s):  
High Pressure ◽  
Continuous Flow ◽  
High Speed ◽  
Fuel Injection ◽  
Light Emitting Diode ◽  
Cone Angle ◽  
High Speed Camera ◽  
Light Emitting ◽  
High Pressure High Temperature ◽  
Spray Visualization

A vessel has been designed for nonreacting fuel-injection experiments with continuous flow of sweep gas at pressures up to 1380 kPa and temperatures up to 200 °C. Four orthogonal windows provide optical access for high-speed spray-visualization using a fast-pulsed light emitting diode (LED) and a high-speed camera. Initial experiments have been conducted to determine spray characteristics of n-heptane. At room conditions, liquid length and cone angle were 170 mm and 14.5 deg, respectively. With air flow in the chamber at 690 kPa and 100 °C, liquid length was considerably shorter at 92 mm and cone angle was wider at 16.5 deg.

Response of conifer species from three latitudinal populations to light spectra generated by light-emitting diodes and high-pressure sodium lamps

2015 ◽  
Vol 45 (12) ◽  
pp. 1711-1719 ◽  
Author(s):  
Kent G. Apostol ◽  
R. Kasten Dumroese ◽  
Jeremiah R. Pinto ◽  
Anthony S. Davis
Keyword(s):  
High Pressure ◽  
Energy Consumption ◽  
Seedling Growth ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Chlorophyll Contents ◽  
Light Spectra ◽  
Supplemental Lighting ◽  
Forest Nurseries

Light-emitting diode (LED) technology shows promise for supplementing photosynthetically active radiation (PAR) in forest nurseries because of the potential reduction in energy consumption and an ability to supply discrete wavelengths to optimize seedling growth. Our objective was to examine the effects of light spectra supplied by LED and traditional high-pressure sodium (HPS) lamps on growth and physiology of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and Engelmann spruce (Picea engelmannii Parry ex Engelm.) seedlings. We used three latitudinal sources for each species: British Columbia (BC), Idaho (ID), and New Mexico (NM). Container seedlings were grown for 17 weeks in the greenhouse under an 18 h photoperiod of ambient solar light supplemented with light delivered from HPS or LED. In general, seedlings grown under LED had significantly greater growth, gas exchange rates, and chlorophyll contents than those seedlings grown under HPS. The growth and physiological responses to supplemental lighting varied greatly among species and seed sources. Generally, LED-grown seedlings from BC had the greatest growth and tissue dry mass followed by ID and NM populations. Compared with HPS, the significant increase in seedling growth and concomitant energy savings with LED (29% energy consumption relative to HPS) demonstrates the promise of using LED as PAR supplemental lighting for container seedling production.

Ultraviolet light‐emitting diode of a cubic boron nitridepnjunction made at high pressure

1988 ◽  
Vol 53 (11) ◽  
pp. 962-964 ◽  
Author(s):  
Osamu Mishima ◽  
Koh Era ◽  
Junzo Tanaka ◽  
Shinobu Yamaoka
Keyword(s):  
High Pressure ◽  
Ultraviolet Light ◽  
Light Emitting Diode ◽  
Light Emitting

scholarly journals Comparison of Light-emitting Diode and High-pressure Sodium Light Treatments for Hydroponics Growth of Boston Lettuce

HortScience ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 477-482 ◽  
Author(s):  
Vincent Martineau ◽  
Mark Lefsrud ◽  
Most Tahera Naznin ◽  
Dean A. Kopsell
Keyword(s):  
High Pressure ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Experimental Treatment ◽  
Light Treatment ◽  
Shoot Biomass ◽  
Light Emitting ◽  
Significant Difference ◽  
Total Light ◽  
Treatment Analysis

Recent irradiance level improvements in light-emitting diode (LED) technology has allowed this equipment to compete as suitable replacements to traditional high-pressure sodium (HPS) lamps in hydroponics growth environments. The current study compares LED and HPS lighting technologies for supplemental lighting in a greenhouse at HydroSerre Mirabel (Mirabel, Quebec, Canada) for the growth of Boston lettuce (Lactuca sativa var. capitata). The light treatments were applied for 2 hours before sunset and 8.5 hours after sunset to extend the photoperiod to 18 hours. An average total light irradiance (natural and supplemental) of 71.3 mol·m−2 for HPS and 35.8 mol·m−2 for LED were recorded over the 4 weeks of each experimental run. Wet and dry biomass of the shoots was recorded. On average, HPS light treatments produced significantly similar shoot biomass compared with LED light treatment, although the LED lamps provided roughly half the amount of supplemental light compared with the HPS lamps during the 4 weeks of the experimental treatment. Analysis of the lettuce samples showed no significant difference in concentrations of β-carotene, chlorophyll a, chlorophyll b, neoxanthin, lutein, and antheraxanthin among the light treatments; however, violaxanthin concentrations showed a statistical difference resulting from light treatment. When measured on an energy basis, the LED lamps provide an energy savings of at least 33.8% and the minimal “regular” HPS provided an energy savings of 77.8% over the HPS treatment.

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