The effect of failure in extended and intermittent photoperiodic lighting on the growth of white spruce container seedlings

1985 ◽  
Vol 15 (4) ◽  
pp. 734-737 ◽  
Author(s):  
J. T. Arnott ◽  
C. S. Simmons
Keyword(s):  
Dark Period ◽  
Dry Weight ◽  
White Spruce ◽  
Shoot Length ◽  
Day Length ◽  
Lighting System ◽  
Usual Definition ◽  
Short Day ◽  
Lighting Systems ◽  
Definition Of

White spruce seedlings (seed source, 58°50′ N) were grown in a container nursery at Victoria, B.C. (48°28′ N) under the following two photoperiod regimes: (i) natural day length artifically extended to 18 h (120 lx from an incandescent source); (ii) natural day length with dark period interruption for 2.5 min every 30 min (120 lx from an incandescent source). Beginning on July 17, 12 weeks after sowing, batches of seedlings experienced a simulated failure of the lighting systems of from 0 to 9 nights. Although the reduced photoperiod did not fit the usual definition of a short day, failure of the lighting system in (i) and (ii) caused significant reductions in seedling shoot length and dry weight and a significant increase in root dry weight.

Weed Growth in Response to Greenhouse Supplemental Lighting

Weed Science ◽  
1975 ◽  
Vol 23 (4) ◽  
pp. 314-316 ◽  
Author(s):  
W. B. Duke ◽  
J. F. Hunt
Keyword(s):  
Light Intensity ◽  
Dry Weight ◽  
Metal Halide ◽  
Lighting System ◽  
Field Growth ◽  
Weed Growth ◽  
Supplemental Lighting ◽  
Lighting Systems ◽  
Growth Habits

Studies were conducted to compare weed growth under lighting systems composed of metal halide (MH) lamps and fluorescent-incandescent (FI) lamps. The MH lamps provided more light intensity and over a 6-week period caused plant dry weight to be 60 to 70% more than for plants exposed to the FI lamps. One week after emergence, all plants under the higher intensity MH lamps had larger stems and cotyledons or first true leaves. Six weeks after planting, weeds grown under the MH lamps had larger leaves, shorter internodes, thicker stems, and, in general, more pubescence than plants under the conventional lighting system. Growth habits of weeds exposed to the MH lamps were similar to those observed for field growth plants.

Effect of day length on reaction of sunflowers to Verticillium wilt

1973 ◽  
Vol 51 (1) ◽  
pp. 23-26 ◽  
Author(s):  
W. E. Sackston ◽  
J. W. Sheppard
Keyword(s):  
Verticillium Wilt ◽  
Dark Period ◽  
Day Length ◽  
Short Day ◽  
Uninoculated Control ◽  
Short Days

Symptoms of Verticillium wilt on inoculated plants of the sunflower cultivar Sunrise appeared sooner and were more severe under long days (16 h light, 8 h dark), or short days with interrupted dark period (10 h light, [Formula: see text] dark, [Formula: see text] light, [Formula: see text] dark), than under short days (10 h light, 14 h dark). Uninoculated control plants flowered in 45 to 47 days under short-day conditions, but reached only the yellow bud stage in 50 to 55 days under long days or short days with interrupted dark period. Development of Verticillium wilt of sunflower is not dependent on the initiation of flowering as it is in some other hosts.

Luminous Environment and the Perceived Environment

2019 ◽  
pp. 15-21
Author(s):  
Banu Manav
Keyword(s):  
Experimental Studies ◽  
Light Output ◽  
Lighting Design ◽  
Lighting System ◽  
Main Concept ◽  
Healthy Environment ◽  
Perceived Environment ◽  
Efficiency Cost ◽  
Lighting Systems ◽  
User Friendly

In lighting design, the main concept is to achieve a healthy environment, which addresses energy efficiency, cost, maintenance, and quality. User-friendly lighting systems shall be adopted to architecture and interior architecture. User control over the lighting system is important, by dimming or increasing light output, by changing the colour of the light sets the inner atmosphere and affects user mood. Standards and codes on lighting shall also be evaluated by means of these topics. The paper aims to analyse how the luminous environment is affective on the perceived environment. Hence, a series of experimental studies and recent research will be evaluated in regard to understanding and designing luminous environment.

Salinity Tolerance of Black Gram Cultivars During Germination and Early Seedling Growth

2018 ◽  
Vol 51 (3) ◽  
pp. 51-68 ◽  
Author(s):  
M.K. Hasan ◽  
M.S. Islam ◽  
M.R. Islam ◽  
H.N. Ismaan ◽  
A. El Sabagh
Keyword(s):  
Salt Stress ◽  
Salinity Tolerance ◽  
Seedling Growth ◽  
Negative Impact ◽  
Germination Rate ◽  
Dry Weight ◽  
Germination Percentage ◽  
Shoot Length ◽  
Sand Culture ◽  
Black Gram

Abstract A laboratory experiment regarding germination and seedling growth test was conducted with three black gram genotypes tested under three salinity levels (0, 75 and 150 mM), for 10 days, in sand culture within small plastic pot, to investigate the germination and seedling growth characteristics. Different germination traits of all black gram genotypes, like germination percentage (GP), germination rate (GR), coefficient of velocity of germination (CVG) greatly reduced, as well as mean germination time (MGT) increased with increasing salt stress. At high salt stress, BARI Mash-3 provided the highest GP reduction (28.58%), while the lowest was recorded (15.79% to control) in BARI Mash-1. Salinity have the negative impact on shoot and root lengths, fresh and dry weights. The highest (50.32% to control) and lowest reduction (36.39%) of shoot length were recorded in BARI Mash-2 and BARI Mash-1, respectively, under 150 mM NaCl saline conditions. There were significant reduction of root lengths, root fresh and dry weight, shoot length, shoot fresh and dry weight in all genotypes under saline condition. The genotypes were arranged as BARI Mash-1 > BARI Mash-3 > BARI Mash-2, with respect to salinity tolerance.

scholarly journals A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Gianluca Serale ◽  
Luca Gnoli ◽  
Emanuele Giraudo ◽  
Enrico Fabrizio
Keyword(s):  
Control Strategy ◽  
Light Emitting Diode ◽  
Cost Savings ◽  
Energy Performance ◽  
Lighting System ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Lighting Control ◽  
Lighting Systems ◽  
Power Densities

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

scholarly journals THE QUARK CONDENSATE IN THE GELL-MANN-OAKES-RENNER RELATION

1996 ◽  
Vol 11 (16) ◽  
pp. 1331-1337 ◽  
Author(s):  
K. LANGFELD ◽  
C. KETTNER
Keyword(s):  
Quark Propagator ◽  
Quark Condensate ◽  
Usual Definition ◽  
Gluon Exchange ◽  
Current Mass ◽  
Definition Of

The quark condensate which enters the Gell-Mann-Oakes-Renner (GMOR) relation, is investigated in the framework of one-gluon-exchange models. The usual definition of the quark condensate via the trace of the quark propagator produces a logarithmic divergent condensate. In the product of current mass and condensate, this divergence is precisely compensated by the bare current mass. The finite value of the product in fact does not contradict the relation recently obtained by Cahill and Gunner. Therefore the GMOR relation is still satisfied.

Effects of carbon dioxide on Pharbitis, Xanthium, and Silene in short days

1974 ◽  
Vol 52 (6) ◽  
pp. 1283-1291 ◽  
Author(s):  
A. N. Purohit ◽  
E. B. Tregunna
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Dry Weight ◽  
Morphological Characters ◽  
Photoperiodic Response ◽  
Pharbitis Nil ◽  
Light Sources ◽  
Short Day ◽  
Unit Leaf ◽  
Silene Armeria

The flowering response and other morphological characters of Pharbitis nil, Xanthium pennsylvanicum, and Silene armeria were studied in environments with different levels of carbon dioxide and oxygen under short-day conditions. Different light sources and intensities were also tested. Irrespective of the light source and intensity used, higher levels of carbon dioxide delayed or inhibited flowering as well as other morphological characters of the short-day plants but induced flowering in the long-day plant. Dry weight per unit leaf area as well as total chlorophyll increased with carbon dioxide concentration. The results are discussed in relation to some other recent reports, and it is proposed that large variations in photosynthetic rates of plants probably alter their photoperiodic response.

A field study of fluorescent and LED classroom lighting

2016 ◽  
Vol 50 (4) ◽  
pp. 631-650 ◽  
Author(s):  
N Gentile ◽  
T Goven ◽  
T Laike ◽  
K Sjoberg
Keyword(s):  
Secondary School ◽  
Field Study ◽  
Energy Savings ◽  
Electricity Consumption ◽  
Visual Comfort ◽  
Lighting System ◽  
Upper Secondary ◽  
Lighting Systems ◽  
Indoor Lighting ◽  
Academic Year

Indoor lighting is facing a massive retrofit to LED lighting. Research is needed to assess whether LED-based lighting can promote energy efficiency, boost visual comfort and support biological functions. This field study considered the lighting of four identical classrooms in an upper secondary school in Helsingborg, Sweden. Two classrooms were fitted with state-of-the-art ceiling pendants containing T5 fluorescent tubes and that had a direct/indirect light distribution (the control rooms). The other two classrooms were fitted with an experimental LED indirect lighting system (the experimental rooms). In the classrooms, 72 students aged 17–18 years performed their usual educational activities over a whole academic year. The light environment, electricity consumption, and students’ mood, light perception and saliva cortisol concentration were monitored. The two lighting systems produced only marginal differences. Overall, the experimental rooms were slightly preferred but achieved only small energy savings due to high parasitic losses.

scholarly journals Experimental model for in vivo determination of dietary fibre and its effect on the absorption of nutrients in the small intestine

1981 ◽  
Vol 45 (2) ◽  
pp. 283-294 ◽  
Author(s):  
Ann-Sofie Sandberg ◽  
H. Andersson ◽  
B. Hallgren ◽  
Kristina Hasselblad ◽  
B. Isaksson ◽  
...  
Keyword(s):  
Small Intestine ◽  
Wheat Bran ◽  
Dietary Fibre ◽  
Dry Weight ◽  
Direct Analysis ◽  
Fresh Weight ◽  
Wet Weight ◽  
Definition Of

1. An experimental model for the determination of dietary fibre according to the definition of Trowell et al. (1976) is described. Food was subjected to in vivo digestion in ileostomy patients, and the ileostomy contents were collected quantitatively, the polysaccharide components of which were analysed by gas–liquid chromatography and the Klason lignin by gravimetric determination. The model was used for the determination of dietary fibre in AACC (American Association of Cereal Chemists), wheat bran and for studies on the extent of hydrolysis of wheat-bran fibre in the stomach and small intestine. The effect of wheat bran on ileostomy losses of nitrogen, starch and electrolytes was also investigated.2. Nine patients with established ileostomies were studied during two periods while on a constant low-fibre diet. In the second period 16 g AACC wheat bran/d was added to the diet. The ileostomy contents and duplicate portions of the diet were subjected to determinations of wet weight, dry weight, water content, fibre components, starch, N, sodium and potassium.3. The wet weight of ileostomy contents increased by 94 g/24 h and dry weight by 10 g/24 h after consumption of bran. The dietary fibre of AACC bran, determined as the increase in polysaccharides and lignin of ileostomy contents after consumption of bran, was 280 g/kg fresh weight (310 g/kg dry matter). Direct analysis of polysaccharides and lignin in bran gave a value of 306 g/kg fresh weight. Of the added bran hemicellulose and cellulose 80–100% and 75–100% respectively were recovered in ileostomy contents. There was no significant difference between the two periods in amount of N, starch and K found in the ileostomy contents. The Na excretion increased during the ‘bran’ period and correlated well with the wet weight of ileostomy contents.4. In conclusion, it seems probable that determination of dietary fibre by in vivo digestion in ileostomy patients comes very close to the theoretical definition of dietary fibre, as the influence of bacteria in the ileum seems small. Bacterial growth should be avoided by using a technique involving the change of ileostomy bags every 2 h and immediate deep-freezing of the ileostomy contents. True dietary fibre can be determined by direct analysis of polysaccharides and lignin in the food, at least in bran. Very little digestion of hemicellulose and cellulose from bran occurs in the stomach and small bowel. The 10–20% loss in some patients may be due to digestion by the gastric juice or to bacterial fermentation in the ileum, or both. The extra amount of faecal N after consumption of bran, reported by others, is probably produced in the large bowel.

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