JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2003 | Volume:4 | Issue:15|Papers Count:5

In this study, sensitivity level of "page", "Unshiou" and "Younesi" mandarins to curing and also effects of fungicide, shrink wrapping, curing and combination of these treatments on mandarin shelf life were investigated. In "page" mandarin, shrink wrapping alone, or with fungicide or curing significantly (P<0.05) reduced weight losses. Fruits, Fungicide, curing, or combination of these treatments significantly (P<0.05) reduced the incidence of penicillium italicum and P. digitatum, but no significant difference was observed for curing and fungicide treatments. In the first year, the ratio of TSS/TA in polyethylene shrink wrapping film was higher than other treatments, whereas, in the second year, the highest ratio of TSS/TA was found in curing with shrink wrapping treatment In "Unshiou" and "Younesi" mandarins, shrink wrapping and shrink wrapping with other treatments significantly (P<0.05) reduced weight losses and increased fruit frirmness. Curing , fungicide, or combination of these treatments with other treatments significantly (P<0.05) reduced the incidence of penicillium sp. Compared to control and shrink wrapping treatments but, no significant effect was found for curing and fungicide treatments. In "Unshiou", in the first year experiments, the ratio of TSS/TA was significantly (P<0.05) higher in shrink wrapping and curing treatments and in the second year, in curing with fungicide and shrink wrapping treatments. While, in "Younesi" mandarin, in the first year, this ratio was higher in curing treatment and in the second year, was higher in curing with fungicide and shrink wrapping treatments. In "Unshiou" and "Page" mandarins, curing had n deleterious affect on fruit skin but, in "Younesi" mandarin, curing produced the storage brown spot around the stem. Therefore. The application of curing instead of fungicide treatment were more effective and can be recommended for future storage of "Page" and "Unshiou" mandarins, whereas curing is not recommended for "Younesi" mandarin.

Biological methods are applied to protect river banks against waves. There are several biological plants grown nearby banks naturally and artificially that reed is the most common. Plants can damp the wave energy and as a result, they stabilize the river banks and slopes. In the present paper based on the experimental studies and dimensional analysis, a parametric model is derived for the wave damping by reed and transmission. To evaluate parameters of the developed model, an experimental study has been carried out. A flume with 8 meters length, 50 cm width and the height of 80 cm was constructed at the Hydraulic Laboratory of Shahid Chamran University (SCU), Iran. Along the flume, a suitable small area was considered for the plant with different populations. More than 80 experiments were conducted and in each experiment waves with 1m, 1.5m, 2m, 3m and 3.5m wave length were produced by and appropriate means. Based on results of the dimensional analysis and the experimental study a model is presented model is in a very good agreement with observed data. This study shows that when the bed length of the biological (reed) protection is increase the transmission coefficient will decrease nonlinealy.

In order determine detachment of fruit persent, suitable shaking amplitude, frequency and cultivars for mechanized harvesting of almond, a 7 *4 * 4 factorial experiment with a complete randomized design design in three replications were conducted. Four levels of shaking amplitude (10, 20, 30 and 40 mm) and four levels of frequency (10, 15, 20 and 25 Hz) were investigated with 7 almond cultivars (Shokufeh, Nonpareil, Azar, Harir, Ferragnes, A 200 and A230). This experiment was conducted in the Sahand horticultural research station of East Azarbijan, and the trees were shaked by a mechanical trunk shaker. Analysis of variance and mean comparison was shown that the effect of shaking amplitude, frequency and cultivars were significant in fruit detachment. It was fond that the most effective detachment of fruit was happened at 40 mm amplitude and 20 Hz frequency. Also the results showed that the amount of detachment fruits increased at the hither amplitude and frequency levels. The results of this research also indicated that "Harir" had maximum and "shokufeh" had minimum fruit detachment. It seems that the cultivars of "Harir". "Nonpareil", "Ferragnes" and "Azar" were more suitable for mechanical harvesting than others.

Accumulation of nitrite and nitrate in foodstuff id considered harmful for human health. In the present study therefore, the effects of processing conditions as well as the storage time on nitrite and nitrate content of coral cultivars of tomatoes were investigated. The experiment was conducted in the department of Technical and Engineering Research, West Azerbaijan Agricultural Research Center. The data were analyzed statistically using the complete randomized block design. In the present work, the effects of heating during processing of tomato pates, sun drying during manufacturing of tomato slices and storage time of tomatoes were studied on the changes of the above-mentioned chemicals. The nitrite and nitrate content of samples were measured using colorimetric method in which the absorbance of coloured complex from the reaction between a diazonium salt with sulphanilamide using N-1- naphthylethylen- diamine (NED) as the coupling agent, was measured at 525 nm. The solutions containing known amounts of nitrite were used to prepare a calibration curve by plotting absorbance against concentration of nitrite in the standard solutions. The results showed that the nitrite content of all samples was than 5 mg/kg and the nitrate content was around 380 mg/kg. The nitrite content of tomatoes increased while the level of nitrate decreased at the same times. During processing of tomato paste and drying of tomato for production of tomato slices changes of nitrate content was monitored and it was shown that in both cases the level of nitrate decreased by 25% and 40% respectively, where as the amount of nitrite increased 69% and 88% respectively at the same time.

The parametric description of the soil water retention curve and hydraulic conductivity are crucial to study water movement and solute transport in the unsaturated soil. Despite the progresses made in the direct measurement of hydraulic properties, the majority of these techniques remained time consuming and costly. Further, due to inherent temporal and spatial variability of these hydraulic characteristics in the field conditions, large number of samples is required to properly characterize area of land. An alternative is then the use of so-called Pedotransfer functions (PTFs) that estimate missing soil characteristics form easily obtainable soil properties. In arid and semi-arid areas, gypsum is a major solid component of the soil. The objective of this study was to derive some Pedotransfer functions to predict the van Genuchten and Mualem-van Genuchten parameters of some gypsiferous soils. Consequently, 35 soil samples with gypsum content ranging from 3.8 to 32.7 percent were collected. The gypsum content was measured by Acetone method, the bulk density by volumetric method, the particle size distribution by covering the particles with Barium Sulfate and the soil water retention curve was obtained using pressure plates apparatus. The easily obtainable variables were in to two groups (i) particle size distribution, bulk density and gypsum content, (ii) bulk density, gypsum content, geometric mean and geometric standard deviation of particle diameter. The stepwise linear regression method was used to derive the PTFs. Two types parametric functions were derived, using these variables. Comparison of the results indicated that the first group of variables had better prediction of the van Genuchten and the Mualem-van Genuchten parameters than the second group. The t test method was used to compare the hydraulic parameters of the soil samples with and without gypsum. This indicated that the gypsum removal increased the water retention at matric potentials of 0, -10, -33, -100, -300, -500 and -1500 KPas (P<0.01). Analyzing the data in more details, a significant difference between the hydraulic parameters was obtained for the soils with and without gypsum compounds.