Tag Archives: moisture.

737–744 P. Kic
Effect of different air velocities on convective thin-layer drying of alfalfa for livestock feeding
Abstract |
Full text PDF (408 kB)

Effect of different air velocities on convective thin-layer drying of alfalfa for livestock feeding

P. Kic

Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, CZ165 21 Prague 6, Czech Republic
Correspondence: kic@tf.czu.cz

Abstract:

Alfalfa (Medicago sativa) is widely used as forage which has very high feeding value. The aim of this paper is to inform about the experimental and theoretical investigations of alfalfa drying in thin layer. Special device for convection drying with air flow passing through material from bottom through supporting trays with sieve by constant temperature was used for drying when air velocity was 0.7 m s-1, 1 m s-1, 1.2 m s-1 and 2.0 m s-1. The results were compared with natural convection drying by the same temperature, but with the 0 m s-1 air velocity. The increased air velocity for convection influenced drying process positively. The results show that the differences between the drying with air velocities 1.2 m s-1 and 2 m s-1 are very small, therefore 1.2 m s-1 could be realised as an optimum. The evaluation of measurement results was focused on curves of drying rate, changes in water content and changes of moisture depending on the time and their mutual relations. Experimental data create the background for calculation of main parameters useful for description and modelling of the drying process, which can be helpful e.g. for decision of optimum drying time. Drying alfalfa for hay by forced convection shortened the drying time as compared with natural convection two and a half times. Drying alfalfa for haylage by forced convection shortened the drying time as compared with natural convection even four times.

Key words:

, , , ,




290–296 J. Tuure, A. Rammo and J. Ahokas
Realtime soil moisture measurement during field work
Abstract |
Full text PDF (513 kB)

Realtime soil moisture measurement during field work

J. Tuure¹, A. Rammo² and J. Ahokas¹*

¹University of Helsinki, Department of Agricultural Sciences Agrotechnology,
Koetilantie 5, FI 00014 Helsinki, Finland
²University of Mosul, College of Agriculture, Mosul Iraq
*Correspondence: jukka.ahokas@outlook.com

Abstract:

Soil moisture affects grain germination. If the seeds are sown in dry soil the germination is poor and the emergence is uneven. In Finland, the fieldwork during the spring sowing season takes a couple of weeks and during this period the soil is drying or it is wetting if there are rains. If the seeds can be sown to optimal soil moisture content this enhances germination and increases the yield.
Soil moisture content and temperature was measured before spring tillage. By utilizing these results a prototype of soil moisture measurement system was built utilizing commercial NIRtechnology moisture sensor. This system could be used in harrows and drills so that the work is done to proper soil moisture content. The principle functioned reliably when properly calibrated and mounted. The measuring system could be further improved with narrower light beam so that the falling soil aggregates would not have interference to the results. This kind of instrumentation could be used in implements.
Harrowing and sowing season could be prolonged with a small impact on yield if the seeds could be sown to advantageous moisture content. This would be also economical because the work capacity and machine sizes could be reduced. Also risk of soil compaction would be less.

Key words:

, , ,




5-13 A. Aboltins and J. Palabinskis
Fruit Drying Process Investigation in Infrared Film Dryer
Abstract |
Full text PDF (392 kB)

Fruit Drying Process Investigation in Infrared Film Dryer

A. Aboltins* and J. Palabinskis

Latvia University of Agriculture, Institute of Agricultural Machinery, Cakstes blvd. 5, Jelgava, LV – 3001, Latvia:
*Correspondence: aivars.aboltins@inbox.lv

Abstract:

The work analyzes three different product (apple slices, banana slices and grape halves) drying process in the infrared film dryer. Such drying takes place at low temperatures (to 40 °C), allowing to keep the maximum value of fresh products. The drying process is analyzed in detail in the first 8 hours. The quantity of water runoff, drying product temperature changes and flowing air humidity changes during drying were analyzed. It demonstrates the impact of the product placement on the drying progress. Using the experimental data, average diffusion coefficients are obtained for each product group. The results showed that diffusion coefficients were changing during the drying process. Using mathematical modelling and experimental data, the concentration-dependent diffusion coefficient for apple slices was obtained. The study finds that apple and banana drying using the infrared film is comparatively successful, but the drying process of the half of grape berry is slower. This can be explained by the impact of grape peel on the water diffusion.

Key words:

, , , ,




215-222 A. Aboltins, and P. Kic
Forced convection in drying of poultry manure
Abstract |
Full text PDF (504 kB)

Forced convection in drying of poultry manure

A. Aboltins¹,* and P. Kic²

¹Latvia University of Agriculture, Institute of Agricultural Machinery, Cakstes blvd. 5, Jelgava, LV–3001, Latvia; *Correspondence: aivars.aboltins@inbox.lv
²Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, 165 21, Prague 6, Czech Republic

Abstract:

Pollution of environment by animal waste can be problem of intensive animal production in many countries with high density of animal farms. The aim of this paper is to inform about the experimental and theoretical investigations of moisture content reduction from poultry manure by forced convection. The experimental data created the background for calculation and modelling, which resulted in definition of the theoretical drying coefficient, useful for description and modelling of the drying process. The theoretical model has been verified and compared with experimental results obtained from the measurement. The laboratory equipment was used for test the forced convective drying of poultry manure due to vertical air streams going from bottom through supporting trays with holes and therefore through the manure up. Changed opened area of trays with different density has been used for definition of main parameters, which can serve especially in designing and construction of the new equipment for housing of poultry or improvement of the use of drying tunnel or in similar applications. The experimental data show that the air flow significantly increase the amount of moisture carried away from the material. Holes´ size does not significantly affect water runoff by convection without additional air flow.

Key words:

, , , ,