Proper management of post-harvest systems is one of the most crucial steps in reducing agricultural losses and waste. This study was aimed to find the effect of forced air pre-cooling of dill using a window air conditioner on its shelf life. For this purpose, a metal frame with dimensions of 2×1×1 m was covered with a polyethylene foam sheet and a window air conditioner (after removing its thermostat) equipped with a controller was connected to one end of this chamber. In the next step, bunches of dill without packaging and the cardboard packaging with polyethylene liner were placed in three different conditions, including without pre-cooling and keeping at ambient temperature, with pre-cooling and keeping at ambient temperature, with pre-cooling and keeping under refrigeration. The results showed that during 4 days of storage, bunches of dill kept at ambient temperature had more total loss (50-60%) but after that, packaging caused severe loss (100%) due to moisture accumulation. If cold storage and packaging was ignored after pre-cooling, total loss would increase swiftly. For this reason pre-cooled dill with proper packaging and refrigeration showed the least amount of total loss (8.95±1.03%), physiological water loss (5.16±1.78%), pH (6.16±0.16), a*(-20.29±1.45) and the highest amount of moisture content (87.60±3.76), hardness (764±50 N), ascorbic acid (2.74±0.05 mg. g-1 of dill dry weight basis), total acceptance (4.1±0.65), L* (43.44±6.39), and b* (20.09±4.31).

The idea of forced eruption or extrusion was first introduced for the treatment of transverse root fractures in 1973 but indications of forced eruption were increased in modern dentistry. The intent of this article is to review the periodontal indications, clinical considerations and techniques for this procedure.

The current study employs CFD to study the forced air cooling of a pyramid shaped porous foam absorber. Herein, a three by three (3´3) array of porous foam absorbers heated with an external heat flux is modeled using the differential equations governing heat and fluid flow through porous media based on the Brinkman- Darcy flow equations and an effective thermal conductivity to account for the porous medium. The numerical simulations are carried out using the COMSOL commercial Computational Fluid Dynamics (CFD) Finite Element based software package. The results of this verification exercise were within 18% of the prior numerical results and within 14% of the archived measured results. Typical results for the velocity and temperature profiles within the porous foam absorbers are shown. A comparison of Nusselt number between our CFD simulations and the heat transfer theory is plotted, showing agreement on the order of 11%. A parametric study involving heat flux, cooling air inlet velocity, porous foam porosity, and porous foam permeability showed that there is a relationship between porosity and the temperature distribution within the porous media. The primary finding of our study is that the more porous the foam absorber media is, the more dependent the effective thermal conductivity is on the thermal conductivity of the fluid used for cooling. If the fluid is air, which has a very low thermal conductivity, the effective thermal conductivity is decreased as the porosity increases, thus diminishing removal of heat from the foam array via the cooling air stream. Based on the parametric study, the best case operating conditions which may allow the pyramidal foam absorber to stay within the max allowable temperature are as follows: porosity = 0.472, inlet air cooling velocity = 50 m/s.

Restoration of severely damaged teeth requires comprehensive, carefully planned pretreatment. Usually, the teeth with fractures or caries extended up to or below the alveolar crest can be treated by conventional surgical crown lengthening at the expense of supporting bone. Forced eruption or extrusion of teeth is an alternative procedure to overcome problems with dental esthetics and removing of supporting tissues.Two case reports are used as a basis for reviewing the forced eruption with and without supracrestal fibrotomy.

An 1D hydrodynamic model has been simulation and developed for gas hold-up and liquid circulation velocity prediction in air-lift reactors. model is based on momentum balance equations and has been adjusted to experimental data collected on a pilot plant reactor equipped with two types of gas distributors and using water as the liquid phase.The model equations described previously constitute a set of non-linear equations which are solved by an iterative procedure (v.b) (c plus). This model has also been combined with mass transfer and the kinetics of a chemical reaction to yield a complete model of the performance of a reactor.

Introduction: Perioperative hypothermia is common during anesthesia and surgery and is accompanied by several complications. Compared to adults, children are at a greater risk of hypothermia and its complications. The aim of this study was to compare forced air and warmer in maintaining normothermia during pediatric surgery.Materials and Methods: This randomized controlled trial was performed on 90 children undergoing elective hernia repair equally distributed in three groups of warmer, forced air and control. Patients’body temperature was recorded preoperatively, intraoperatively, at the end of surgery and at the end of the postoperative care unit (PACU) stay. Time between anesthetic discontinuation and tracheal extubation and duration of PACU stay were also noted.Results: Intraoperative and postoperative body temperature and body temperature on exit from PACU were significantly higher in forced air group in comparison to warmer and control groups and in warmer group in comparison to control group (P<0.05). Time between anesthetic discontinuation and tracheal extubation and duration of PACU stay were significantly shorter in forced air group compared to warmer and control groups and in warmer group compared to control group (P<0.05).Conclusion: In comparison between the two methods (Warmer vs.Forced air), we found that forced air was significantly more effective in maintaining normothermia during pediatric hernia repair.

The objective of the present study was to detemine the influence of airflow velocities on precooling process of pomegranate with thin peel (Shahvar variety), to evaluate the cooling rate and temperature distribution in this product in order to design and optimize the precooling system. Forced air cooling was applied for precooling the center (arils) and peel (outer layer) of pomegranate. Airflow velocities were 0.5, 1, and 1.3 m/s and the air temperature was 7.2°C in the air tunnel during the experiments. For calculating cooling rates (half and seven-eighths cooling time), lag factor and cooling coefficient were determined from the experimental data by a regression analysis. Also, cooling heterogeneity was evaluated in the center and outer layer of pomegranate at different airflow velocities. The results showed that with increasing the airflow velocity from 0.5 to 1.3 m/s, cooling rates increased. Furthermore, with enhancing the airflow velocity, half and seven-eighths cooling time decreased up to 19.35 and 21.76% in the center and by 32.95 and 19.63 in the peel, respectively. This finding was due to increasing convective heat transfer coefficient. Cooling heterogeneity decreased from 0.5 to 1 m/s and then increased at the airflow velocity of 1.3 m/s. This parameter was dependent on airflow velocity, cooling coefficient and lag factor. The influence of airflow velocity was low after 6400s from starting the cooling process both in center and in peel. The overall results demonstrated that application of this method can explain unsteady heat transfer in precooling process of pomegranate and probably can be used for the other similarly shaped fruits.

Background and objectives: A considerable amounts of Fruits and vegetables is lost during the post-harvest stages. One of the most important processes that reduces fruit loss and extends their shelf life is pre-cooling. In this process, biological activities of the products are decreased rapidly. The aim of this study was designing and constructing the forced air pre-cooling system for horticultural products. Material Martials and methods: In this study, the forced air pre-cooling system of horticultural products was designed and constructed according to the industrial pattern. To evaluate the performance and uniformity of cooling process in the system, the precooling of Peach was performed using fruit pallets with the three kinds of packages namely one-row package, two and three-row packages. In addition, the airflow rate was evaluated in three levels consists of 0. 5, 1 and 1. 5 liters per second per kilogram of product. Results: The evaluation of results indicated that the air velocity field was uniform around the constructed precooling system with cross section dimension of 550×1200 mm and the height of 2050 mm. The suction fan power was 0. 5 hp and the cooling capacity of the system about zero º C. Therefore, all fruits located in the different location of pallet were cooled with an acceptable uniformity viewpoint of the cooling time and temperature. Also, the standard error of cooling time was not significant. Among the studied factors, the effect of airflow rate on the average 3/4 th cooling time of fruits in different boxes in the pallet and their standard deviation were significant. Increasing the airflow rate decreases the cooling time and improves the uniformity of cooling between the various packages, so that with three times increasing the airflow rate, the standard deviation decreases 59%. According to the results, the kind of package had a significant effect on the average 3/4 the cooling time of fruits and the minimum and maximum cooling time were related to the three rows and two rows boxes, respectively; but its effect on the standard deviation was not significant. Conclusion: The developed precooling system could create and distribute of cold air uniformity between the fruits boxes in different locations of the pallet. There were no significant differences between the cooling time of fruit in both airflow rate of 1 and 1. 5 lit s-1 kg p-1. Also, the rate of energy consumption is considerable in the high airflow rates. Therefore, it is recommended usage of cold airflow rate of 1 lit s-1 kg p-1. Although the three rows box had the lowest cooling time, due to the mechanical damage probability, it's using had no advantage as compared to one-row box.