Evaluation of chilling requirement and heat accumulation in three European pear cultivars and genotypes

2021 ◽  
pp. 69-76
Author(s):  
M. Ebtedaei ◽  
K. Arzani ◽  
S. Sarikhani
Keyword(s):  
Chilling Requirement ◽  
Heat Accumulation ◽  
European Pear

scholarly journals Chilling Requirement and Postrest Heat Accumulation in Peach Trees Inoculated with Peach Latent Mosaic Viroid

2002 ◽  
Vol 127 (3) ◽  
pp. 333-336 ◽  
Author(s):  
Philip G. Gibson ◽  
Gregory L. Reighard
Keyword(s):  
Prunus Persica ◽  
Infectious Agent ◽  
Delayed Response ◽  
Base Temperature ◽  
Chilling Requirement ◽  
Significant Delay ◽  
Heat Accumulation ◽  
Chilling Requirements ◽  
Growth Chambers ◽  
Peach Trees

Peach [Prunus persica (L.) Batsch (Peach Group)] trees bloom in response to chilling and postrest heat accumulation. The peach cultivar Coronet exposed to a graft-transmissible, infectious agent known as peach latent mosaic viroid (PLMVd) blooms at a different time than noninoculated trees of the same cultivar. To determine if chilling requirements differed between trees inoculated with PLMVd and noninoculated controls, fruiting shoots collected from the orchard and artificially chilled containerized trees were forced in a greenhouse. Additional artificially chilled containerized trees were forced under constant temperatures in growth chambers to determine if postrest heat accumulation requirements differed. There was no difference in the chilling requirement of the fruiting shoots collected from the field although the shoots exposed to PLMVd had a delayed response and fewer responded to greenhouse forcing conditions. The containerized trees also showed no differences in chilling requirements during winter 1999 or 2000. Trees inoculated with PLMVd had a significant delay in bloom. Growth chamber data revealed a significantly higher base temperature for heat accumulation in the PLMVd inoculated trees.

scholarly journals Increasing Chilling Reduces Heat Requirement for Floral Budbreak in Peach

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 245-252 ◽  
Author(s):  
William R. Okie ◽  
Bryan Blackburn
Keyword(s):  
Prunus Persica ◽  
Southeastern United States ◽  
Critical Factor ◽  
Curvilinear Relationship ◽  
Chilling Requirement ◽  
Heat Accumulation ◽  
Exponential Relationship ◽  
Fixed Amount ◽  
Chilling Temperatures ◽  
Heat Requirement

Response to chilling temperatures is a critical factor in the suitability of peach [Prunus persica (L.) Batsch] cultivars to moderate climates such as in the southeastern United States. Time of bloom depends on the innate chilling requirement of the cultivar as well as the timing and duration of cold and warm temperatures experienced by the buds. Most current chilling models have considered dormancy break a sequential process: after appropriate chilling is received, a fixed amount of heat accumulation will produce bloom. This research shows that as chilling exposure increases, the time and heat accumulation required for peach floral budbreak decreases in an exponential relationship. When chilling is ample, a sequential, two-part dormancy model is adequate to describe budbreak, and increased chilling has little effect on heat requirement. In lower-chilling situations relative to a particular cultivar, the curvilinear relationship between chilling and heat requirement results in more heat being required for budbreak. This relationship, in conjunction with the range of chilling requirement found among the buds on a tree, results in an extended, asymmetrical budbreak.

CHILLING REQUIREMENT FOR DORMANCY BUD BREAK IN EUROPEAN PEAR

2011 ◽  
pp. 85-88 ◽  
Author(s):  
A.A. Kretzschmar ◽  
L.M. Brighenti ◽  
L. Rufato ◽  
T.R. Pelizza ◽  
F.N. Silveira ◽  
...  
Keyword(s):  
Bud Break ◽  
Chilling Requirement ◽  
European Pear

Accelerating laser processes with a smart two-dimensional polygon mirror scanner for ultra-fast beam deflection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florian Roessler ◽  
André Streek
Keyword(s):  
Energy Distribution ◽  
Real Time ◽  
Laser Processing ◽  
High Speed ◽  
Beam Deflection ◽  
Two Dimensional ◽  
Heat Accumulation ◽  
Field Programmable ◽  
Drill Holes ◽  
Average Laser

Abstract In laser processing, the possible throughput is directly scaling with the available average laser power. To avoid unwanted thermal damage due to high pulse energy or heat accumulation during MHz-repetition rates, energy distribution over the workpiece is required. Polygon mirror scanners enable high deflection speeds and thus, a proper energy distribution within a short processing time. The requirements of laser micro processing with up to 10 kW average laser powers and high scan speeds up to 1000 m/s result in a 30 mm aperture two-dimensional polygon mirror scanner with a patented low-distortion mirror configuration. In combination with a field programmable gate array-based real-time logic, position-true high-accuracy laser switching is enabled for 2D, 2.5D, or 3D laser processing capable to drill holes in multi-pass ablation or engraving. A special developed real-time shifter module within the high-speed logic allows, in combination with external axis, the material processing on the fly and hence, processing of workpieces much larger than the scan field.

High-chilling requirement apple cultivar has more accentuated acrotony than low-chilling one in mild winter region

Trees ◽  
2021 ◽  
Author(s):  
Rafael Henrique Pertille ◽  
Idemir Citadin ◽  
Leonardo Silva Patto ◽  
Tatiane Luiza Cadorin Oldoni ◽  
Silvia Scariotto ◽  
...  
Keyword(s):  
Apple Cultivar ◽  
Chilling Requirement ◽  
Mild Winter

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

scholarly journals Parameters Optimization of Auxiliary Gas Process for Double-Wire SS316L Stainless Steel Arc Additive Manufacturing

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 190
Author(s):  
Wei Wu ◽  
Jiaxiang Xue ◽  
Wei Xu ◽  
Hongyan Lin ◽  
Heqing Tang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Evaluation System ◽  
Gas Flow ◽  
Interactive Effect ◽  
Parameters Optimization ◽  
Heat Accumulation ◽  
Auxiliary Process ◽  
Strength And Stiffness

Serious heat accumulation limits the further efficiency and application in additive manufacturing (AM). This study accordingly proposed a double-wire SS316L stainless steel arc AM with a two-direction auxiliary gas process to research the effect of three parameters, such as auxiliary gas nozzle angle, auxiliary gas flow rate and nozzle-to-substrate distance on depositions, then based on the Box–Behnken Design response surface, a regression equation between three parameters and the total score were established to optimized parameters by an evaluation system. The results showed that samples with nozzle angle of 30° had poor morphology but good properties, and increasing gas flow or decreasing distance would enhance the airflow strength and stiffness, then strongly stir the molten pool and resist the interference. Then a diverse combination of auxiliary process parameters had different influences on the morphology and properties, and an interactive effect on the comprehensive score. Ultimately the optimal auxiliary gas process parameters were 17.4°, 25 L/min and 10.44 mm, which not only bettered the morphology, but refined the grains and improved the properties due to the stirring and cooling effect of the auxiliary gas, which provides a feasible way for quality and efficiency improvements in arc additive manufacturing.

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