scholarly journals Control of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) by using the parasitoid Eretmocerus eremicus (Hymenoptera: Aphelinidae) in a tomato greenhouse with a negative-pressure forced ventilation system

2012 ◽  
Vol 54 (0) ◽  
pp. 77-81 ◽  
Author(s):  
Keitaro Sugiyama ◽  
Naoki Ooishi ◽  
Tsutomu Saito ◽  
Hideki Moriya
Keyword(s):  
Bemisia Tabaci ◽  
Negative Pressure ◽  
Ventilation System ◽  
Forced Ventilation ◽  
Eretmocerus Eremicus

scholarly journals Effect of Mechanical Ventilation on Accidental Hydrogen Releases—Large-Scale Experiments

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3008
Author(s):  
Agnieszka W. Lach ◽  
André V. Gaathaug
Keyword(s):  
Mechanical Ventilation ◽  
Mass Flow ◽  
Large Scale ◽  
Ventilation System ◽  
Hydrogen Gas ◽  
Forced Ventilation ◽  
British Standard ◽  
Confined Spaces ◽  
Series Of Experiments ◽  
Rate Limit

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces, such as underground garages. The purpose was to find the mass flow rate limit, hence the TPRD diameter limit, that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway, and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard 315 mm diameter outlet. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzles from different hydrogen reservoir pressures. Both types of mass flow, constant and blowdown, were included in the experimental matrix. The analysis of the hydrogen concentration of the created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases, together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

scholarly journals Optimizing air velocity for the underfloor forced ventilation to protect a refrigerated warehouse from frost heaving

2018 ◽  
Vol 38 (3) ◽  
pp. 321-327
Author(s):  
Jingfu Jia ◽  
Manjin Hao ◽  
Jianhua Zhao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Frost Heave ◽  
Forced Ventilation ◽  
Air Velocity ◽  
Set Up

Forced or natural ventilation is the most common measure of frost heave protection for refrigerated warehouse floor. To optimize air velocity for the underfloor forced ventilation system of refrigerated warehouse, a steady state three-dimensional mathematical model of heat transfer is set up in this paper. The temperature fields of this system are simulated and calculated by CFD software PHOENICS under different air velocity, 1.5m/s, 2.5m/s or 3.5m/s. The results show that the optimized air velocity is 1.5m/s when the tube spacing is 1.5m.

scholarly journals Efficacy of Eretmocerus eremicus and cyantraniliprole on Bemisia tabaci (MED whitefly), 2017

2017 ◽  
Vol 42 (1) ◽  
Author(s):  
Vivek Kumar ◽  
Katherine Houben ◽  
Cindy L McKenzie ◽  
Lance S Osborne
Keyword(s):  
Bemisia Tabaci ◽  
Eretmocerus Eremicus

scholarly journals A Forced Ventilation Micropropagation System for Photoautotrophic Production of Sweetpotato Plug Plantlets in a Scaled-up Culture Vessel: I. Growth and Uniformity

2001 ◽  
Vol 11 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Jeongwook Heo ◽  
Sandra B. Wilson ◽  
Toyoki Kozai
Keyword(s):  
Ipomoea Batatas ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Photon Flux ◽  
Air Distribution ◽  
Culture Vessel ◽  
Forced Ventilation ◽  
Photoautotrophic Growth ◽  
Plantlet Growth ◽  
Ventilation Rates

An improved forced ventilation micropropagation system was designed with air distribution pipes for uniform spatial distributions of carbon dioxide (CO2) concentration and other environmental factors to enhance photoautotrophic growth and uniformity of plug plantlets. Single-node stem cuttings of sweetpotato [Ipomoea batatas (L.) Lam. `Beniazuma'] were photoautotrophically (no sugar in the culture medium) cultured on a mixture of vermiculite and cellulose fibers with half-strength Murashige and Skoog basal salts in a scaled-up culture vessel with an inside volume of 11 L (2.9 gal). CO2 concentration of the supplied air and photosynthetic photon flux on the culture shelf were maintained at 1500 μmol·mol-1 and 150 μmol·m-2·s-1, respectively. Plantlets grown in forced ventilation systems were compared to plantlets grown in standard (natural ventilation rate) tissue culture vessels. The forced (F) ventilation treatments were designated high (FH), medium (FM), and low (FL), and corresponded to ventilation rates of 23 mL·s-1 (1.40 inch3/s), 17 mL·s-1 (1.04 inch3/s), and 10 mL·s-1 (0.61 inch3/s), respectively, on day 12. The natural (N) ventilation treatment was extremely low (NE) at 0.4 mL·s-1 (0.02 inch3/s), relative to the forced ventilation treatments. On day 12, the photoautotrophic growth of plantlets was nearly two times greater with the forced ventilation system than with the natural ventilation system. Plantlet growth did not significantly differ among the forced ventilation rates tested. The uniformity of the plantlet growth in the scaled-up culture vessel was enhanced by use of air distribution pipes that decreased the difference in CO2 concentration between the air inlets and the air outlet.

scholarly journals Impact of Negative Pressure in a Room Due to Increased Airtightness in Residential Apartment Housing

2019 ◽  
Vol 111 ◽  
pp. 01094
Author(s):  
Yoshihiro Toriumi ◽  
Takashi Kurabuchi
Keyword(s):  
Negative Pressure ◽  
Ventilation System ◽  
Air Conditioner ◽  
Drain Pipe ◽  
Multiple Factors ◽  
Air Intake ◽  
The Impact

This study surveyed the impact of a negative pressure in a room in a highly airtight residential apartment with Class 3 ventilation (natural air intake and mechanical exhaust). The results of the study are as follows. 1) A room may reach an excessive level of negative pressure depending on how the ventilation system is used. 2) Noise from the drain pipe of a room air conditioner caused by negative pressure in the room is dependent on how the drain pipe is installed. 3) An experiment was conducted to investigate the mechanism of a seal break in a toilet trap. However, the seal did not break. Thus, seal breaks may be caused by multiple factors.

OPTIMUM DESIGN OF FORCED VENTILATION SYSTEM OF PIGLET HOUSE USING COMPUTER SIMULATION

2002 ◽  
Author(s):  
I. Lee ◽  
W. Park ◽  
B. Yu ◽  
J. Yun ◽  
J. Chun ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Optimum Design ◽  
Ventilation System ◽  
Forced Ventilation

scholarly journals Gas analysis devices for controlling the ventilation system in the house

2018 ◽  
pp. 31-35
Author(s):  
V. Kozubovskyy ◽  
I. Aljakshev
Keyword(s):  
Gas Sensors ◽  
Electrochemical Sensors ◽  
Ventilation System ◽  
Gas Analysis ◽  
Living Room ◽  
Forced Ventilation ◽  
Proportional Control ◽  
Autonomous Mode ◽  
Point Control ◽  
And Control

Now in modern houses for the purpose of energy saving use the airtight doors and windows. This causes the need for forced ventilation of the spaces. Usually use a mechanical ventilation system controlled by gas sensors. Gas sensors control the permissible concentration of certain gas components in the living room and on/off, if necessary, a ventilation system. Depending on the type of living spaces used point control, proportional control, or control of the rate of growth of concentration. We have developed gas analyzers of oxygen, СО2  , СО to control the concentration of these gases in the living rooms and control the forced ventilation. Electrochemical sensors of these gases were used as inexpensive, selective and non-consuming electricity. The devices developed on their basis have insignificant weight, dimensions and can work in the autonomous mode with the power from the battery.

scholarly journals A Forced Ventilation Micropropagation System for Photoautotrophic Production of Sweetpotato Plug Plantlets in a Scaled-up Culture Vessel: II. Carbohydrate Status

2001 ◽  
Vol 11 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Sandra B. Wilson ◽  
Jeongwook Heo ◽  
Chieri Kubota ◽  
Toyoki Kozai
Keyword(s):  
Ipomoea Batatas ◽  
Starch Content ◽  
Soluble Sugar ◽  
Ventilation System ◽  
Soluble Sugars ◽  
Leaf Tissue ◽  
Photon Flux ◽  
Culture Vessel ◽  
Forced Ventilation ◽  
Starch Concentration

Sweetpotato [Ipomoea batatas (L.) Lam., `Beniazuma'] plantlets were grown photoautotrophically (without sugar) for 12 days in an improved forced ventilation system designed with air distribution pipes for uniform spatial distributions of carbon dioxide (CO2) concentration. Enriched CO2 conditions and photosynthetic photon flux (PPF) were provided at 1500 μmol·mol-1 and 150 μmol·m-2·s-1, respectively. The forced (F) ventilation treatments were designated high (FH), medium (FM), and low (FL), corresponding to ventilation rates of 23 mL·s-1 (1.40 inch3/s), 17 mL·s-1 (1.04 inch3/s), and 10 mL·s-1 (0.61 inch3/s), respectively, on day 12. The natural (N) ventilation treatment was extremely low (NE) at 0.4 mL·s-1 (0.02 inch3/s), relative to the forced ventilation treatments. Total soluble sugar (TSS) and starch content were determined on day 12. Total soluble sugars (sucrose, glucose, fructose) of FH plantlets were lowest in leaf tissue and highest in stem tissue as compared to other ventilation treatments. Starch concentration was higher in leaf tissue of FH or FM plantlets as compared to that of FL or NE plantlets. Plantlets subjected to FH or FM treatments exhibited significantly higher net photosynthetic rates (NPR) than those of the other treatments; and on day 12, NPR was almost five times higher in the FH or FM treatment than the FL or NE treatments. Carbohydrate concentration of plantlets was also influenced by the position of the plantlets in the vessel. Within the forced ventilation vessels, leaf TSS of FH and FM plantlets was similar regardless of whether plantlets were located near the inlet or outlet of CO2 enriched air. However, under FH or FM conditions, leaf starch concentration was higher in plantlets located closest to the CO2 inlet as compared to the outlet.

scholarly journals RESULTS OF INSPECTION OF THE STATE OF PROVIDING THE MICROCLIMATE IN THE PIG FARM WITH A NEGATIVE PRESSURE VENTILATION SYSTEM

2021 ◽  
pp. 168-177
Author(s):  
Vitalii Yaropud ◽  
Yelchin Aliyev
Keyword(s):  
Air Temperature ◽  
Negative Pressure ◽  
Cooling System ◽  
Ventilation System ◽  
Air Cooling ◽  
Negative Pressure Ventilation ◽  
Normal Limits ◽  
Air Supply ◽  
Air Cooling System ◽  
Pig Farm

The most popular microclimate system today is based on a negative pressure ventilation system. Because it is easier to use and consumes less energy than any other forced ventilation system. The purpose of the research is to inspect the room for keeping piglets on rearing with a negative pressure ventilation system to identify shortcomings and deviations of the microclimate parameters necessary for further improvement. According to the results of the inspection of the rearing room for piglets, it was found that according to the existing system of negative pressure in the rearing room for piglets, most indicators (air velocity, ammonia, carbon dioxide, hydrogen sulfide, oxygen) are within normal limits. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it was found that the air temperature in the room does not meet the recommended limits and reaches 30 °C, while the maximum recommended temperature for piglets for fattening is 20 °C. The air temperature is uneven along the length of the room, which is caused by uneven air supply from the vents. According to the results of the inspection of the room for piglets with a negative pressure microclimate system, it was found that the relative humidity at the height of the animals is higher than the recommended norms and reaches 95%, while the recommended humidity for piglets for fattening is not more than 80%. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it can be stated that it is necessary to improve the air cooling system and replan the ventilation ducts of the ventilation system to ensure even air flow.

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