Showing 3 results for B. Ghobadian
Gh. Chegini, B. Ghobadian, M. Barekatin,
Volume 7, Issue 4 (winter 2004)
Abstract
The difficulties in the storage of fruit juice and the use of juice powder in various food processing industries has made the juice powder attractive to consumers and producers. Making powder from fruit juice is one of the most complex methods of fruit processing.The hygroscopic nature of fruit juice component and its thermoplastic properties has caused the drying time control and the transportation of the product from the drying zone to the next stage to become very difficult. In this investigation with laboratory spray dryer, the effective parameters on orange juice powder deposit on the wall of the spray dryer was studied. The results indicate that the powder can not be made without the use of additives. Using liquid glucose as an additive to orange juice concentration increased the dryer performance and reduced the wall deposit considerably. With the help of liquid glucose additive, spray dryer optimum conditions were obtained with a feed flow rate of 15 ml/min, inlet air temperature of 130oC and outlet air temperature of 85oC. The results from the statistical analysis of the experimental data show that the parameters of inlet air temperature and feed flow rate have significant effects on the dryer yield and wall deposit both individually and jointly. By increasing inlet air temperature and feed flow rate, the dryer yield decreased but wall deposit increased. In spite of using suitable additives, the wall deposit was still in the range of 14 to 65 %. The results of experiments indicate that the main cause of wall deposit can be attributed to the wall high temperature. It is, therefore, necessary to keep the wall temperature below the orange powder sticky point temperature to prevent rising temperature in wall deposit. For the orange powder containing 2% moisture, the sticky point temperature is 44oC. To control the wall temperature, a dryer with double partition wall chamber and a cooling system is proposed.
D. Momeni Abkharaki, B. Ghobadian, A. Hemmat, S. Minaei,
Volume 8, Issue 4 (winter 2005)
Abstract
Differential lock is a means of improving tractor performance. This system causes the revolution of the axles to become equal. It, improves traction, decreases abrasion of drive tires, improves fuel consumption, and increases tractor work rate. Despite advantages of the system, differential lock has not been optimized in Iran. Thus, a semi-automatic differential lock system for MF-285 tractor was designed and developed. First of all, the different parts of the system were designed, selected, assembled. Under critical conditions, the designed system should disengage the differential lock. Critical conditions for engaging this system are: using of independent brake pedals, high forward speed, and turning the steering wheel. For sensing and measuring the critical conditions, proper sensors were selected. Output signals of these sensors were sent to a micro controller to decide the continuous engaging or disengaging. Finally, a MF-285 tractor was equipped with the designed system. The tractor performance in primary tillage was evaluated using a mounted moldboard plow with a width of 110 cm and a working depth of 25 cm.
These tests showed that unbalanced weight distribution on wheels and unequal traction capacity under drive wheels cause the slip of one wheel to be 6 percent higher thananother. This system improves the unequal slip problem and decreases fuel consumption by 0.5 L/ha.
S. R. Hasan Beygi Bidgoli, B. Ghobadian, P. Nassiri, N. Kamalian,
Volume 8, Issue 4 (winter 2005)
Abstract
In addition to farm operations, power tillers in Iran are also engaged in load and passenger transportation. Inspite of their noise and adverse effects on power tiller drivers and bystanders, they have not been adequatly investigated. The initial survey in the present investigation on a 13-hp power tiller at 2200 rpm engine speed revealed that its noise was 92 dB(A), compared to the standard limit of 85 dB(A) which is disappointing. The test site was prepared according to international standards and the noise signals emitted from the system were measured and analyzed in time and frequency domains for audio frequency range (20 – 20000 Hz).
The results showed that the noise intensity was higher by 7.74 to 10.75 dB(A) for the microphone position at driver’s ear compared to the bystanders position and that the engine speed played a great role in noise generation for power tiller. This is because the noise increases up to 8.5 dB(A) with engine speed variations. Finally, the power tiller prediction models of sound pressure levels at driver’s ear and bystanders were determined using the experimental data.
