Response of Tomato Sugar and Acid Metabolism and Fruit Quality under Different High Temperature and Relative Humidity Conditions

The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little information about the precise interaction between them on tomato fruit quality.The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits,and to determine the best relative air humidity for fruit quality under high temperature environments.Four temperature treatments(32℃,35℃,38℃,41℃),three relative air humidity(50%,70%,90%)and four duration(3,6,9,12 d)orthogonal experiments were conducted,with 28℃,50%as control.The results showed that under high temperature and relative air humidity,the activity of sucrose metabolizing enzymes in young tomato fruits changed,which reduced fruits soluble sugar content;in addition,enzyme activities involved phosphopyruvate carboxylase(PEPC),mitochondria aconitase(MDH)and citrate synthetase(CS)increased which increased the content of organic acids(especially malic acid).Eventually,vitamin C,total sugar and sugar-acid ratio decreased significantly,while the titratable acid increased,resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit.Specifically,a temperature of 32℃and a relative air humidity of 70%were the best cultivation conditions for tomato reproductive growth period under high temperature.Our results indicating that fruit quality reduced under high temperature at the flowering stage,while increasing the relative air humidity to 70%could alleviate this negative effect.Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.

Modeling of Soybean Plant Sap Flow

Soybean (Glycine max. (L.) Merr.) sap flow during the growth stages in relation to soil moisture, nutrition, and weather conditions determine the plant development. Modeling this process helps to better understand the plant water-nutrition uptake and improve the decisions of efficient irrigation management and other inputs for effective soybean production. Field studies of soybean sap flow took place in 2017-2021 at Marianna, Arkansas using heat balance stem flow gauges to measure the sap flow during the reproductive growth stages R3-R7. Plant water uptake was measured using the lysimeter-container method. The uniform sap flow-based hydraulic system in the soil-root-stem-leaf pathway created negative water tensions with osmotic processes and water surface tensions in stomata cells as water evaporation layers increase are the mechanism of the plant water uptake. Any changes the factors like soil water tension, solar radiation, or air relative humidity immediately, within a few seconds, affect the system’s balance and cause simultaneously appropriate reactions in different parts of the system. The plant water use model was created from plant emergence, vegetative to final reproductive growth stages depending on soil-weather conditions, plant morphology, and biomass. The main factors of the model include solar radiation, air temperature, and air relative humidity. The effective sap flow uptake occurs around 0.8 KPa VPD. Further research is needed to optimize the model’s factors to increase the plant growth dynamics and yield productivity.

Control Means and Data Analysis of Environmental Factors of Facility Watermelon in Beijing Area

In this study, the environmental indicators （including temperature, light, air relative humidity and CO2 concentration） of facility watermelon in Beijing area were monitored with US350 environmental sensor during the whole growth period. The results showed that in the solar greenhouses in Beijing area, the average air temperature was in the range of 10.67-29.95 ℃ during the whole growth period of watermelon, the average soil temperature ranged from 16.92 to 35.10 ℃, the average light intensity changed from 268.37 to 13 842.60 Ix, the average air relative humidity ranged from 52.40% to 94.26%, and the average CO2 concentration was in the range of 455-631 ml/m3; and in the spring greenhouses in Beijing area, the variation range of average air temperature was 14.05-29.84 ℃ during the whole growth period of watermelon, the average soil temperature ranged from 17.47 to 28.12 ℃, the average light intensity was in the range of 55.80-12 858.64 Ix, the average soil moisture content ranged from 18.19%-34.56%, the variation range of average air relative humidity was 20.72%-96.26%, and the average CO2 concentra- tion was in the range of 351-544 ml/m3,

Removal of inhalable particles from coal and refuse combustion by agglomeration with solid nuclei

Airborne inhalable particles are a potent environmental pollutant. Formed via industrial processes, separation of these particles is difficult using conventional clean up techniques. In this work, solid nuclei particles of different chemical compositions were introduced into an agglomeration chamber with simulated flue gases to investigate their ability to remove these particles. Organic nuclei were able to capture more inhalable particles from coal-derived fly ash than inorganic nuclei, though these proved more effective for the agglomeration of inhalable particles in refuse-derived fly ash. Increasing the diameter of the solid nuclei benefitted the agglomeration process for both types of ash. Varying the local humidity changed adhesion between the particles and encouraged them to aggregate. Increasing the relative humidity consistently increased particle agglomeration for the refuse-derived ash. For coal-derived fly ash, the removal efficiency increased initially with relative humidity but then further increases in humidity had no impact on the relatively high efficiencies. After agglomeration in an atmosphere of 62% relative humidity, the mean mass diameter of inhalable particles in the coal-derived fly ash increased from 3.3 to 9.2 μm. For refuse-derived fly ash, agglomeration caused the percentage of particles that were less than 2μm to decrease from 40% to 15%. After treatment at a relative humidity of 61%, the mean size of inhalable particles exceeded 10 μm.

Experimental Analysis on Influencing Factors of NO_(x)emission in Gas-Fired Heating and Hot Water Combi-Boilers

To study the influencing factors of NO_(x)emission in gas-fired heating and hot water combi-boilers,a boiler with the maximum heat input of 26.0 k W was selected,and influencing factors including flue restrictor diameter,fan power,nozzle aperture,nozzle ejection distance and air relative humidity on NO_(x)formation were determined.The NO_(x)test rig has been built and the concentration of NO_(x)at the rated heat input and the NO_(x)weight value(NO_(x))_(pond)with different heat input in the dry flue gas have been tested respectively according to the test methods in Chinese national standard GB 25034-2010.The results show that with the increase of the diameter of flue restrictor at exhaust outlet,the NO_(x)concentration at the rated heat input and the NO_(x)weight value(NO_(x))_(pond)with different heat input in the dry flue gas decreased by 26.9%and 5.9%;with the increase of the diameter of flue restrictor at air intake inlet,the NO_(x)and(NO_(x))_(pond)decreased by 36.5%and 16.0%;with the increase of fan power,the NO_(x)and(NO_(x))_(pond)can be decreased by 48.4%and 16.1%;with the increase of ejection distance of nozzle,the NO_(x)and(NO_(x))_(pond)decreased by 7.7%and 6.8%;with the increase of aperture of nozzle,the NO_(x)and(NO_(x))_(pond)increased by 5.2%and 2.3%;with the increase of air relative humidity,the NO_(x)decreased by 16.4%and the(NO_(x))_(pond)basically remains unchanged.The analysis of the influence factors of NO_(x)emission can be provided as reference for the optimization design of combi-boilers with low NO_(x)emission.

Analysis of Influencing Factors on NO_x emission in Gas-Fired Heating and Hot Water Combi-Boilers Based on Orthogonal Method

In order to determine the sensitivity of influencing factors on NOx emission in gas-fired heating and hot water combi-boilers,the orthogonal method was adopted in this paper.Five predominant factors affecting the formation of NOx and four levels were selected to be analyzed,including the diameter of flue restrictor,power of fan,ejection distance of nozzle,aperture of nozzle and relative humidity of air.The test plan was designed by employing L16(45)orthogonal array,and 16 groups of experiments were conducted.The test results were analyzed with range analysis and variance analysis.The results indicated that the power of fan has the greatest influence on the formation of NOx of the gas-fired combi-boilers,followed by the diameter of flue restrictor and the relative humidity of air,while the ejection distance of nozzle and aperture of nozzle have little effect on the formation of NOx.In addition,with the selected optimal combination of five factors,a minimum NOx volume fraction is obtained,which confirms the superiority of the orthogonal test.The research finding has a certain guiding significance for the reduction of NOx formation of gas-fired heating and hot water combi-boiler.