JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2001 | Volume:2 | Issue:6|Papers Count:10

The effect of soil moisture content and plowing depth on soil pulverization was investigated. In this experiment a split- split plots design, with moisture content levels as the main plots and plowing depth levels as the sub-plots was used. Four levels of soil moisture content and two levels of plowing depth were replicated three times. Moldboard plow and disk harrow were used for tillage operations. This experiment was conducted in two areas, one with silty clay loam and the other with loamy soil.The results indicated that in the silty clay loam soil, clod mean weight diameter (MWD) was minimized at 15-18% moisture content (M.C.) and was maximized at 10-13% M.C. (in both 15-20 cm and 25-30cm depth). In the loamy soil, MWD was minimized at 18-20% M.C. in 15-20cm plowing depth, while in 25-30cm plowing depth, it was minimized at 13-15% M.C. as well as 15-18% M.C. The maximized MWD in both 15-20cm and 23-30cm plowing depths was abserved 10-13% M.C. Also, MWD at 15-20cm plowing depth was smaller than that of 25-30cm plowing depth at all moisture contents considered.Disking operations showed that if primary tillage is performed at optimum moisture content depending on soil type, proper seed bed conditions could be obtained with one or two disking operations.As far as residue coverage and soil inversion was concerned, the highest and lowest coverage was observed at 13-15% and 10-13% M.C., respectively. Also, residue coverage was reduced with increasing plowing depth.

There are ways of preservation which increase shelf life of food products including olives.One of the most valuable fruits Because of the limitation of harvesting time and deteriorability of olive, especially in tropical area. It must be conserved and distributed in whole of our country: Olive fruit (Zard, Sevillana and Manzanila variety) were processed as "Spanish green olive". The treatment included a first step at light pH (Lye treatment), a lactic acid Fermentation and a final period of conservation.The results of two years showed that reducing of pH in the samples with starter were considerably higher than without starter. After two month pH of samples with starter reduced from 6.75 to 4.02-4.10 in the first year and from 7.18 to 4.13 in the second year and also acidity of samples with starter reached from zero to 0.14-0.26 percent in the first year and from zero to 0.25-0.45 percent in the second year.Differences of data between 2 years can probably related to harvesting time, amount of sugar in olive, condition and way of bittering, temperature of incubation and amount of starter.Olive is highly susceptible to deteriorative agents in postharvest situations. Canning is considered to be one of the preservative methods which can prolong storage life of olive by maintaining its quality.In this investigation three varieties of olive namely:Zard, Sevillana and Mamzanila were processed and canned following bitterness removal, lye treatment and lactic acid fermentation steps. Canned olives were treated with or without starter and effect of starter on pH value, acidity and fermentation time was measured in two consecutive years.Results indicated that in samples with starter decrease in pH value in the first and second year washingher (6.75 to 4.02 and 7.18 to 3.68) as compared to samples without starter (6.75 to 5.1 and 7.18 to 4.13)Acidity value for samples with starter in the first had increased from zero to 0.14 and 0.25 percent, and in second year from zero to 0.25 to 0.45 percent. Whereas in samples without starter acidity increased from zero to 0.05 and 0.06 percent in the first year and from zero to 0.3 and 0.45 percent in the second year.The differences in values of pH and acidity obtained in two consecutive years can be attributed to the differences in the harvesting time and sugar content of fruit and also shortcomings in conduction of experiments.

Since, cement production industries after steel and aluminum industries are the most cost ones, the use of pozzolans in blended cement production, decrese considerably the find price of cement. ON the other hand, adding pozzolanic materials to concrete, both adding to cement and concrete aims to in proving engineer properties of concrete specially riological (such as adhesion and homogeneity), mechanical and durability properties (Such as resistance against destruction of chemical attecks).In this research, effect of micro silica on the compressive strenth and comparing microsilica pozzolanic activity with natural Pozzolan and rice husk in gilan and mazandaran provenances were considered, the results show rice husk ash in the two mentioned regions have the similar pozzolanic activity, in addition, rice husk ash pozzolanic activity is more than natural pozzolan and comparable with microsilica.

In thus study, field efficiency and cost of plowing and disking in Kermanshah was determined. The universal 650 tractor was used for the study. Two methods of data gathering were applied; 1. An operator filled out questionnaire before the operation started. 2. Some parameters were measured while operation took place.Analytical results showing the plowing field efficiency was ranged between 3675% in different field sizes; however, for the field size bigger than four hectare the field efficiency was the same value. For the disking, field efficiency was between 50-75%. These values were lower than values presented by the ASAE standards. Cost of plowing and disking per hectare was 32988 Rials and 8297 Rials respectively. The investment interest had the highest percentage of tractor cost. If one uses a tractor for 900 to 1560 hours annally, the fixed cost can be 49% of total cost.There are ways of preservation which increase shelf life of food products including olives.One of the most valuable fruits Because of the limitation of harvesting time and deteriorability of olive, especially in tropical area. It must be conserved and distributed in whole of our country: Olive fruit (Zard, Sevillana and Manzanila variety) were processed as "Spanish green olive". The treatment included a first step at ligh pH (Lye treatment), a lactic acid Fermentation and a final period of conservation.The results of two years showed that reducing of pH in the samples with starter were considerably higher than without starter. After two month pH of samples with starter reduced from 6.75 to 4.02-4.10 in the first year and from 7.18 to 4.13 in the second year and also acidity of samples with starter reached from zero to 0.14-0.26 percent in the first year and from zero to 0.25-0.45 percent in the second year.Differences of data between 2 years can probably related to harvesting time, amount of sugar in olive, condition and way of bittering, temperature of incubation and amount of starter.Olive is highly susceptible to deteriorative agents in postharvest situations. Canning is considered to be one of the preservative methods which can prolong storage life of olive by maintaining its quality.In this investigation three varieties of olive namely:Zard, Sevillana and Mamzanila were processed and canned following bitterness removal, lye treatment and lactic acid fermentation steps. Canned olives were treated with or without starter and effect of starter on pH value, acidity and fermentation time was measured in two consecutive years.Results indicated that in samples with starter decrease in pH value in the first and second year washingher (6.75 to 4.02 and 7.18 to 3.68) as compared to samples without starter (6.75 to 5.1 and 7.18 to 4.13)Acidity value for samples with starter in the first had increased from zero to 0.14 and 0.25 percent, and in second year from zero to 0.25 to 0.45 percent. Whereas in samples without starter acidity increased from zero to 0.05 and 0.06 percent in the first year and from zero to 0.3 and 0.45 percent in the second year.The differences in values of pH and acidity obtained in two consecutive years can be attributed to the differences in the harvesting time and sugar content of fruit and also shortcomings in conduction of experiments.

Enzymatic interesterification is a potential method for modification of physicochemical properties of edible oils and is expected to become an alternative route for the production of fats and oils with desired characteristics. The major advantage of this method can be resulted in the preparation of a wide varity of specific products of different compositions and properties, depending on the specificity of the lipases used. The use of enzymatic methods should also reduce environmental loading in comparison with conventional processes.Lipase-catalyzed interesterification can be performed with free or immobilized enzyme preparation in stirred tank or fixed bed reactors with or without organic solvent in the reaction medium. Inter-esterification and hydrolysis were followed and related to the initial water content of the reaction mixture. Hydrolysis can not be totally avoided because lipase need small amount of water to be active. The optimum moisture content of the lipase is know to be %10. The results obtained, showed that the process decreased melting point, solid fat content and changed triglycerids composition of blends with exchanging the acyl groups in triglyceride molecule depending on the mass fractions of the substrates, temperature, time, dosase and types of enzymes applied.

Onion cultivation through the common methods in East Azarbayjan, leads to low soil fertility, due to the use of fine sands to help germination of onion seeds. One way to solve this problem and reduce the production cost is onion transplanting. In addition, Onion with short and superficial root must be grown in soil which is rich in nutrients, organic matters and consisted of a soft structure, with no clod consisted. The present study was conducted to determine the suitable tillage method in preparing fine seed-bed and increasing the organic matters in topsoil under semi arid climate and loamy soil conditions.A split plot experiment based on randomized complete block design with three replications was used. The main plots concerning the primary fall-tillage were as following:1- Mold board plow in 25 Cm depth.2- Chisel plow in 15 cm depth3- Disk harrow in 10cm depth.Sub plots concerning the secondary tillage before transplanting were harrowing by disk and rotary tiller in 8-10 cm depth.During the experiment, some physical and chemical properties of soil, such as bulk density, penetration resistance (Con Index), organic matter, percentage of plant residues in various stages of operation and in different depth of soil, plant establishment, bulbs weight and diameter average and yield were measured and analyzed.The following results were obtained:1- The moldboard plow had the most effect on inversion of residues. When a soil-horrowing by disk or rotary tiller carried out after plowing, the residues spread in top and subsoil more evenly. Chisel plow had the least effect of burial of residues in soil.2- Plowing by moldboard and chisel plow had the most effect on reduction of bulk density, penetration resistance and consequently increasing the soil porosity. Therefore, these implements with preparing of suitable conditions for plant establishment and growth resulted in the highest yield.3- In all treatments of secondary operation, the rotary tiller was more effective in soil pulverization than disk.

Various methods of stabilityanalysis for earth slope have been represented in cIuding the simple methods such as wedge and Fellenius and the rigorous method such as Janbu and Morgenstern. The purpose of this study is the comparison of these methods and consideration of the advantages and disadvantages of each method. Also a new computer program "STDAM" for earth slopes stability analysis using all existing methods have been prepared and represented. This program has graphical and numerical capability in results representing, and can analyse all different loading conditions for earth slopes design.The coparison was carried out among Fellenius, Bishop, Spenser and Janbu methods. As a criteria for checking the accuracy of each method the Finite element metod was also used, and the following conclusions were obtained.1- Fellenius method is not recommended because of its low accuracy.2- Solving of Spencer method formulas is very difficult and takes much time, also most of the times, the results are incorrect so the method is not recommended.3- Bishop method is relatively simple and reliable, but its accuracy in conditions involving the external forces such as earthquake force and also in cohesive soils is low.4- Janbu method is one of the best methods because of its high accuracy and relative simplicity.5- The results obtained by finite element method are close to those obtained by Bishop and Janbu methods which confirms validity of these methods.

There are many difficulties in measuring rivers bed load. So it has been usually estimated as a ratio of suspended load. The ratios range change at different conditions and must be found by field measurement. One of the suggested method is reservoir sedimentation survey which be used in this research work. The volume and weight of deposits in the seasonal reservoir that is digged in Chamrood riverbed (near Kashan city, Isfahan province, Iran), is determined using surface and depth survey. First the ratio is estimated 31 % by suppose that deltaic sediment as bed load and lacustric sediment as suspended load. Then particle size distribution curves of sediments are carefully analyzed using two methods and by changing boundary values, the ratios calculated. Result decreases in one method, but hasnt significant change in another one. It is recommended that these methods used in seasonal and perennial reservoirs.