نشریه مهندسی بیوسیستم ایران
سال پنجاه و سوم شماره 2 (تابستان 1401)

The firmness of the orange texture can be considered as an important criterion for determining the quality and freshness of this product and its texture characteristics have a great influence on its acceptability and marketability. Orange is an important product in the south of Kerman province, having sufficient knowledge and information about its texture mechanics is also important for the development of orange industries and processing equipment, especially orange concentrate production industries. In response to need the mechanical properties of the orange texture, punch test method was proposed as a suitable and non-destructive testing method. In this research, firmness, force, stress and consumption energy of five common orange varieties (Valencia, March, Washington Navel, Blood and Local Jiroft) was determined and compared by punch test method with seven punch diameters (4.3, 4.6, 9.7, 9.5, 11.1, 12.7 and 14.3 mm). The results showed that the effect of variables of punch diameter, variety, and also the interaction effect of punch diameter × variety on the force, firmness, stress and energy were significant at 1% level. The combination treatment of local cultivar with a punch diameter of 12.7 mm has the maximum value of force (79.0 N) and firmness (7.9 N/mm), and the minimum value of force (15.5 N) and firmness (1.5 N/mm) was obtained in the combination treatment of blood variety and punch diameter of 4.8 mm. The highest mean of stress (1.5 MPa) and the lowest mean stress (0.3 MPa) were in the combination treatment of local variety and punch diameter of 4.3 mm, and the combination treatment of blood variety and punch diameter was 14.3 mm.

Barberry fruit is a native plant of Iran and belongs to the Berberidaceae family and is available in different species and colors. Iran is the first producer of barberry in the world. The eating fresh barberry fruits is limited due to spoilable, and the production of barberry-based products is one of the important methods for reduocing the waste of this fruit. Fruit juice production is one of the efficient methods in reducing agricultural waste. The filter press method is known as one of the common and effective methods for the juice extraction. In the present study, the effects of the layer height (at five levels of 15, 30, 45, 60 and 75 mm), cylinder diameter (at five levels of 40, 45, 50, 55 and 60 mm), and loading rate (at five levels 6, 12, 18, 24 and 30 mm/min) on the percentage of extracted juice from barberry, juice density, moisture content of pomace, final pomace porosity, specific energy consumption, and power consumption were studied and optimized. The results showed that the change in input variables resulted in changes in the percentage of extracted juice in the range of 33.9 to 51.8%, the juice density in the range of 1013.7 to 1047.2 kg/m3, the final pomace porosity in the range of 2.6 to 12.8%, and moisture content of pomace in the range of 19 to 41%. The results are suitable for optimizing the barberry water extraction process, using axial pressure devices and can be used to determine the optimal operating conditions of the juice making devices.

Soil compaction refers to process that increases density, decreases volume and continuity of pores, decreases water and air permeability, and increases mechanical strength. One of important parameters for evaluation of soil compaction is pre-compaction stress, which is often considered as stress at threshold of soil compaction. Plate sinkage test is an appropriate method for determining soil pre-compaction stress. In this research, for determining pre-compaction stress the experimental test of plate sinkage was used on a sample of arable soil (sandy clay loam) at the level of 15% moisture content based on dryness and density 1500 kg.m-3. Then mechanical properties of soil was determined. Plate sinkage test was simulated as the form of two-dimensional and symmetric in Abaqus software and the pre-compression stress was also predicted by this method. Also, the amount of stress and displacement changes in the transverse and longitudinal layers of arable soil were analyzed. There was a high correlation (R2 =0.99) between the data extracted from the simulation model and the experimental data. Examination of compressive stress and displacement in different layers in the soil depth showed that the amount of stress and displacement in layers close to load level is more and decreases amount of stress and displacement as it progresses to the lower layers. Also, in this research, image processing technique by MATLAB software has been applied as a method to estimate soil compaction. As a general conclusion, the finite element method and image processing can be used for assessment of compacted region of soil.

Strawberry (Fragaria ananassa) is susceptible to postharvest fungal agents. Therefore, the application of suitable methods such as essential oils (EOs) and edible coatings to control the fruit decay and maintain the quality of strawberry fruit during the postharvest period is necessary. However, the application of EOs is limited due to low water solubility, high vapor pressure and physical and chemical instability. In the current study, thyme (Thymus vulgaris L.) and peppermint (Mentha longifolia) EOs were extracted, and their nanoemulsion prepared by the spontaneous emulsification method. In the next step, layer-by-layer method was applied for coating of strawberries fruit surface with the prepared nanoemulsions and with carboxymethyl cellulose (CMC). The quality attributes and post-harvest wastes of fruits were evaluated during storage period at 0, 3, 6, 9 and 12 days. According to the results, the combination of EOs nanoemulsion with CMC decreased fruit microbial growth during the storage period. The decay index of the control sample, nanoemulsion of peppermint EO 0.5% + CMC 0.5%, and nanoemulsion of thyme EO 0.5% + CMC 0.5% were 25, 16.7, and 13.3%; respectively. Also, the samples coated with nanoemulsion of EOs with CMC had lower weight loss percentage as well as firmer texture than strawberries without coating (control treatment). On the other hand, antioxidant activity and soluble solid content of coated fruits were better retained than the control sample. In general, the treatments have a high potential to maintain fruit quality and decrease postharvest losses of strawberry fruit.

In the present study, an electro-hydraulic system for repositioning the soil shield of a rotary tiller was designed, developed, and evaluated to make it automated for performing variable rate tilling operation. The reposition of the soil shield was studied in the opening and closing stages from 0° to 80° and vice versa, with a 10° and 20° increment under laboratory and field conditions, respectively. Under laboratory conditions, the speed average of soil shield reposition in the opening and closing stages were 102.0±9.2 and 79.0±8.7 deg/s, with the time average in opening and closing stages of 0.11±0.02 and 0.15±0.01 s, respectively. The correlation coefficients between the requested position for the soil shield and the position created by the hydraulic actuator under laboratory conditions in both opening and closing states were R2 = 0.99 (RMSE = 0.7 deg). Under field conditions, the speed average of the soil shield reposition at three travel speeds of 2.6, 3.5, and 4.8 km/h in the opening stage were 97.7, 99.1, and 99.1 deg/s and in the closing stage were 77.3, 78.3, and 78.7 deg/s, respectively. The correlation between the requested position for the soil shield and the position created by the hydraulic actuator in both opening and closing states were R2 = 0.99 (RMSE = 1.2 deg) and R2=0.99 (RMES=1.3 deg), respectively. The soil shield repositioning system can be performed in less than 0.3 s in-field, making it an effective and practical tool for performing variable rate tillage.

Conversion of tree and grass pruning wastes, as abundant and available lignocellulosic sources, into biofuels can be a viable alternative to fossil fuels that pollute the environment. In the present study, flammable briquettes were produced from the pruning remnants of urban trees including mulberry, elm, acacia and ash, as well as grass using a natural binder i.e. frankincense. Then, the optimal density and friction of the produced briquettes under the influence of pressure, moisture, temperature, mixing percentage and additive parameters were investigated using regression methods, support vector machine (SVM) and genetic algorithm. The results showed that with increasing moisture between 9 to 17%, the density of briquettes decreases. Also, the examination of mixing percentage showed that by decreasing the percentage of sawdust and increasing the percentage of grass, density and friction force decrease. The most optimal sample of this experiment was determined with a mixing percentage of 87.5% sawdust and frankincense 10% at a temperature of 100 °C, a pressure of 10 bar and a moisture content of 13%. In this case, the average density and friction force of the briquettes were 1020 kg/m3 and 44 N/mm respectively. The results showed that regression model of the density and friction test related variables are significant at 5% level. Hence, the variables are involved in the explanation of friction and density. According to the results, the high calorific value and low calorific value of briquettes produced from grass and sawdust are more, and the calorific value of additives has a significant impact on the process of briquette production due to the high sticking effect.