Thermal boundary effects on a GT liner structure

GT combustor liners are subjected to mechanical and thermal loads that damage the structure and reduce their operational life. Among those, the thermo-acoustic instabilities develop, generating pressure oscillations because of the interaction between heat release, acoustic waves and structure vibrations. The vibratory behaviour of the structure is the result of these phenomena and undergoes repeated reversals of the main deformation mechanisms as a function of the operating load of the engine. Monitoring and evaluating the operational load history and the life consumption rate of combustor components is essential to sustain a reliable risk-based maintenance in the GT combustion hardware. The non-linear material behaviour can activate possible interactions causing coupled damage mechanisms and become a life threatening mode of failure. A methodology for modelling both the dynamic and static behaviour of a GT cannular combustion chamber by utilizing a combined fluid-structure approach is presented in this study. Together with the calculation of the heat fluxes through the liner, the effects of the modifications at the thermal boundary conditions were used to investigate the modifications in the liner structural properties and the stresses development at different GT loads. The monitored pressure oscillations during operations has been investigated by performing both acoustic and structural dynamics. A correlation with the observed failure has been proposed by investigating stress relaxation phenomena’s, creep and plastic effects for base load and part load operations

Postharvest quality of cucumber grown by soilless culture

XXVth International Horticultural Congress -- AUG 02-07, 1998 -- BRUSSELS, BELGIUMWOS: 000088354600035Shelf life of cucumber fruits is dependent on the preharvest conditions prevealing during the growing season as well as storage conditions. The aim of this study is to investigate the effects of growing factors in soilless culture on postharvest performance of cucumbers. Test plants were grown in bags with 8 liters rooting volume filled with perlite. The factors examined were (1) nutrition system, (2) bag type and (3) cultivar. The tested nutrition systems were open and closed systems. Vertical and horizontal bags containing one or two plants per bag, respectively, were compared. Cultivars Afrodit, Efes and Rawa were used in testing the above mentioned two variables. Fruits of the cucumber plants belonging to each treatment were packed in PE bags and stored for 21 days at 13 degrees C temperature and 85-90 % relative humidity. During the storage; weight loss of fruits, changes in fruit colour, chilling injury symptoms and general appearance scores were determined at three-day intervals and fruit firmness was measured weekly. The tested nutrition systems and bag types were found to be effective mainly on weight loss, however, cultivar difference exerted significant effects on all of the examined parameters. Afrodit had the best postharvest performance.Commiss European Union, European Crop Protect Assoc, Interbrew, Int Soc Hort Sci, Kredietbank & CERA Bank, ABB Insurances, Kluwer Acad Publishers, Les Marques Natl, Luxembourg, Minist Agr, Luxembourg, Minist Agr Nat Management & Fisheries, Minist Dev Cooperat, Minist Small & Medium Size Enterprise & Agr, Minist Flemish Community, Minist Walloon Reg, Norwegian Agcy Dev Cooperat, Palm Breweries, Prod Board Hort, SABENA Belgian Airlines, Tech Ctr Agr & Rural Cooperat, Wageningen Univ & Res Ctr, Benelux Soc Hort Sc

Optimization of suitable tests for rapid screening of tomato genotypes for drought stre ss tolerance at seed germination and vegetative development stages

Objective: This study was conducted to determine the suitability of drought stress induced by PEG-6000 for rapid screening of tomato genetic resources against drought stress. Material and Methods: Two cultivars; M28 F1 and Alyans F1 known as tolerant and sensitive, respectively; were tested. In seed germination test, two different PEG concentrations (4% and 6%) were compared with the control. The seedling stage test was performed in water culture. In this experiment, (1) bare rooted seedlings of which rooting medium were removed and (2) seedlings with rooting medium were used. Drought dose was Ψs= -1.0 MPa (full dose) and gradually increased (-0.25, -0.50, -0.75 and -1.0 MPa) every 48 hours from 7 days after planting. Results: In seed germination test, the decrease in vigour index under drought stress was lower in M28 variety. In water culture, stress symptoms appeared slowly if the seedlings with rooting medium were used. The decrease in plant growth characteristics, and chloropyll, carotenoid and relative water content and increase in proline content under stress were lower in M28 Conclusion: It was concluded that the seed germination test by 4% PEG-6000 and water culture in which the drought stress was created by PEG-6000 (Ψs= -1.0 MPa) can be used to screen tomato genetic matierials for drought stress tolerance. © 2022 Journal of Agriculture Faculty of Ege University. All right reserved

Influence of Potassium and Calcium Levels on Severity of Tomato Pith Necrosis and Yield of Greenhouse Tomatoes

2nd International Symposium on Tomato Diseases -- JAN 31, 2009 -- Kusadasi, TURKEYWOS: 000305324000056Two greenhouse experiments were carried out between the years of 2004-2006 in Aegean Region of Turkey to determine the influence of different potassium and calcium levels on severity of tomato pith necrosis caused by several pathogens belonging to genus Pseudomonas and Erwinia. The influence of three potassium (100 ppm, 200 ppm and 400 ppm) and two calcium (60 ppm and 120 ppm) levels on pith necrosis caused by four different bacteria (P. corrugata, P. cichorii, P. viridiflava and E. carotovora subsp. carotovora) were determined. The experiments were arranged on a greenhouse bench using a factorial randomized plot design with 30 characters and 3 replications. The plants were inoculated artificially two mounts after transplanting by spraying bacterial suspension (10(8)cfu/ml) onto the pruning sites. Lengths of pith necrosis were evaluated according to 0-5 scale two mounts after inoculation. The yields of the plants were measured for each treatment. In both of the experiments differences in potassium and calcium levels influenced the response of the plants to tomato pith necrosis and significant differences between treatments were observed. Two years results showed that treatments comprising highest levels of potassium (400 ppm) and calcium (120 ppm) not only reduced disease index significantly for most of the bacteria, but also led to the highest yield. http://www.actahort.org/books/808/index.htmT.R. Prime Ministry State Planning Organization [DPT-04-03]The research was supported by a grant from the T.R. Prime Ministry State Planning Organization (DPT-04-03)

Effects of nitrogen and potassium nutrition on plant growth, yield and fruit quality of cucumbers grown in perlite

International Symposium on Greenhouse Management for Better Yield and Quality in Mild Winter Climates -- NOV 03-05, 1997 -- ANTALYA, TURKEYWOS: 000081941300058This study was carried out during autumn, 1995. Nine different nutrient solutions containing 100, 200 and 300 ppm of N and K in various combinations were tested on cucumbers (cv. Alara) grown in glasshouse in perlite. Nitrogen concentrations were found to influence plant growth, yield and fruit quality. The use of 300 ppm N decreased plant growth and total yield. Symptoms of powdery mildew were lowest at 200 ppm N+200 or 300 ppm K where yields were in general high. It was concluded that the N concentration of the nutrient solution should not be more than 200 ppm and the K concentration should be between 200-300 ppm for profitable cucumber production in perlite.Int Soc Horticultural Sci, Commiss Protected Cultiva

Effect of different irrigation schedules, substrates and substrate volumes on fruit quality and yield of greenhouse

This study was conducted to determine the effects of three irrigation schedules in combination with locally available substrates and different bag volumes on yield, fruit quality and water consumption of tomato (cv. Fantastic). The substrates were: (1) perlite, (2) pumice, (3) volcanic ash, (4) perlite + peat (4:1, v/v), (5) pumice + peat (4:1, v/v) and (6) volcanic ash + peat (4:1, v/v). Irrigation was carried out according to the drainage volume as (1) once, (2) twice and (3) four times a day. The experimental design was split split plots with 3 replicates. The main plots, subplots and sub-subplots were irrigation schedule, substrate volume (4 and 8 litres) and substrate, respectively. Cumulative yield at two week intervals and some quality parameters (average fruit weight, total soluble solids, total dry matter content, pH, EC, vitamin C, titratable acidity) were determined. Experimental factors were found to significantly affect on yield after the 10th week. The higher total yields were obtained from plants grown in perlite+peat (7.4 kg/plant) and perlite (7.2 kg/plant). 8 litres rooting volume per plant resulted in a higher total yield (7.4 kg/plant) in comparison with 4 litres (6.2 kg/plant). Total yield obtained from the plants irrigated once a day (6.4 kg/plant) was lower than those obtained from the plants irrigated twice (6.9 kg/plant) and four times (7.1 kg/plant) daily. Fruit quality parameters varied according to treatments and sampling dates

Effect of different irrigation schedules, substrates and substrate volumes on fruit quality and yield of greenhouse tomato

International Symposium on Growing Media and Hydroponics -- AUG 31-SEP 06, 1999 -- KASSANDRA, GREECEWOS: 000169963500032This study was conducted to determine the effects of three irrigation schedules in combination with locally available substrates and different bag volumes on yield, fruit quality and water consumption of tomato (cv. Fantastic). The substrates were: (1) perlite, (2) pumice, (3) volcanic ash, (4) perlite + peat (4:1, v/v), (5) pumice + peat (4:1, v/v) and (6) volcanic ash + peat (4:1, v/v). Irrigation was carried out according to the drainage volume as (1) once, (2) twice and (3) four times a day. The experimental design was split split plots with 3 replicates. The main plots, subplots and sub-subplots were irrigation schedule, substrate volume (4 and 8 litres) and substrate, respectively. Cumulative yield at two week intervals and some quality parameters (average fruit weight, total soluble solids, total dry matter content, pH, EC, vitamin C, titratable acidity) were determined. Experimental factors were found to significantly affect on yield after the 10(th) week. The higher total yields were obtained from plants grown in perlite+peat (7.4 kg/plant) and perlite (7.2 kg/plant). 8 litres rooting volume per plant resulted in a higher total yield (7.4 kg/plant) in comparison with 4 litres (6.2 kg/plant). Total yield obtained from the plants irrigated once a day (6.4 kg/plant) was lower than those obtained from the plants irrigated twice (6.9 kg/plant) and four times (7.1 kg/plant) daily. Fruit quality parameters varied according to treatments and sampling dates.Agr Res Ctr Macedonia & Thrac