Barley: Effect of airflow reversal on fixed bed drying

Maize is one of the most important economic crops in the world. The integrity of maize grains directly affects the economic value of the maize as a main commodity that depends on the percentage of grains broken (POGB) in mechanized harvesting. Decreasing grain processing breakage is key to achieving mechanical harvesting with high quality. It is difficult to ensure a low POGB, because it depends on different maize varieties, their moisture contents, threshing devices and harvester working speeds. In this paper, the effects of these factors on the POGB are investigated when the working speed of the harvester is 1.0 m·s−1, 1.5 m·s−1 and 2.0 m·s−1, respectively. The different threshing forms, including tangential-axial-flow (TAF), axial-flow with nail-tooth (AFN), axial-flow with rasp bar in big space (AFRBBS) and axial-flow with rasp bar in small space (AFRBSS), are summarized. The POGB of TAF was 5.4% and it was the lowest of four threshing devices when the working speed of the harvester was 1.0 m·s−1, which was suitable to thresh maize at a low working speed. Maize Demeiya No. 1 (DMYN1), XianDa205 (XD205), Demeiya No. 3 (DMYN3) and Hayu189 (HY189) were harvested at different harvester working speeds, and the POGB of maize DMYN1 was the lowest among the four maize varieties. The POGB increased with increases in the working speed of the harvester and the moisture content of the maize grains. The POGB reached a minimum value of 3.5% when maize XD205 with the lowest moisture content was harvested. The results can provide a reference for choosing the maize variety, its moisture content, the threshing device and the working speed of the harvester for decreasing grain processing breakage.

This study thoroughly investigated the impact of initial moisture content and curing time on metakaolin (MK)-based geopolymer stabilized soft soil. The stabilized soft soil was characterized with an unconfined compressive strength test, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), and compaction test. The geopolymer was used at different concentrations (5%, 10%, and 15% of the dry weight of the soil), and the soft soil was prepared at its initial moisture content, which ranges from 0.75 LL to 1.25 LL. The results of the test indicate that there was an increase in yield stress at low initial moisture content. Conversely, the yield stress experienced a decrease at high initial moisture content. Furthermore, the strength of geopolymer-stabilized soil increased as the curing time increased, regardless of the binder and initial moisture contents. The microstructure analysis confirmed that the stabilized soil had a denser microstructure, the formation of homogeneous gel, and fewer microcracks and pores. As the automatic compaction test revealed, the maximum dry density increased at higher binder contents while the optimum moisture content decreased. This research demonstrates that stabilizers made with metakaolin can efficiently stabilize soft soils. It is worthwhile to conduct further studies on the durability, shear tests, and cost of using geopolymer for soil stabilization under varying environmental conditions.

Properties of aged tablets prepared by the wet granulation method were found to be affected by the moisture content of the granules. In this study, the storage-induced changes in hardness, disintegration and drug release were evaluated for tablets made by direct compression of three different bases with different initial moisture content. Tablets with high initial moisture content were found to increase in hardness upon storage. The magnititude of such increase is dependant upon the physical properties of the base and the absolute moisture content. The increase in hardness may increase the disintegration time and decrease drug release. Tablets with low initial moisture content were minimally affected by storage. The gain of moisture by some of these tablets led to enhancement in disintegration and drug release. Among the tablets studied lactose based tablets with different initial moisture content were found to be the most resistant to changes upon storage.

In microwave-vacuum drying, thermal energy is replaced by electric energy for heating the material. The additional application of a sufficient vacuum results in a gentle treatment, and specific product features such as aroma and flavor components, and color can be conserved. A crisp texture results from puffing due to expansion when moisture evaporates within the product, and is related to porosity. Using strawberries, a statistical central composite design was applied to relate specific drying energy and evaporation rate as well as raw and bulk density, and particle size distribution to absorbed microwave power input ranging from 2.4 kW kg−1 to 10.5 kW kg−1 dry matter, and to an initial moisture content of 0.17 kg kg−1 to 0.73 kg kg−1 on dry basis, achieved by convective predrying. A low initial moisture content and high microwave power lead to products with low density, porous structure and optimum puffing effects, but shows disadvantages with respect to moisture evaporation rate and energy utilization. On the other hand, optimum efficiency results from the use of raw materials with a high initial moisture content and from applying a high microwave power input.

Soaking tests were conducted to determine the rate of water absorption in Newbonnet long‐grain rough rice ranging from 14 to 30% initial moisture content (dry basis) at 11, 20, 30, 40, and 50C. Four rewetting models were compared, and the following model by Becker (1959) was found to best fit the experimental data, while the rice moisture content during soaking was lower than about 40% (dry basis):M(t) = M0+Δo+α*√t(see a list of symbols at the end of the article). the absorption rate, dM/dt, increased with temperature and decreased with initial moisture content. A regression equation was obtained to relate the parameter α to temperature and initial rice moisture content. the initial moisture gain was not significantly affected by temperature and initial rice moisture content. the average initial moisture gain over the test temperature range was 0.75 percentage points.

This paper concerns with heterogeneous modeling of deep-bed grain dryers based on two-phase model by taking into account coupled heat and mass transfer within grains. This model also consider axial mass and heat dispersion in the fluid phase. The dynamic two-phase equations are solved numerically by finite difference with alternating direction implicit method algorithm, and then applied to simulate humidity and temperature profile of drying gas across dryers together with moisture content and temperature of grains. The capabilities of these models were compared with experimental data obtained from available literatures, under drying conditions such as temperature and absolute humidity of drying gas and moisture content of grains. The simulation results show that the dynamic of corn drying within the bed is well predicted by the two-phase model.

A method of determining the moisture content of bulk wheat grain

Effects of initial temperature and moisture content on heat generation during degradation of municipal solid waste

Measurements of the rate of imbibition by isolated cotyledons of soybean (Glycine max (L.) Merr cv Wayne) indicated that water uptake rates were slowed by low temperatures and by low initial moisture contents of the tissue. The role of water viscosity in the temperature effects on imbibition was examined, and a linear relation between imbibition rate and the reciprocal of viscosity was found only for seeds of very high initial moisture content. Adding solutes which lowered the surface tension, or increased the wetting ability of the water, yielded markedly increased rates of imbibition, especially for tissue of low initial moisture content. The data are interpreted as indicating a first component of water entry which is a wetting reaction influenced by the surface tension of the water, and a second component which resembles water flow through a porous matrix and is influenced by the water viscosity. We speculate that damage to soybeans during imbibition, such as in the case of chilling injury, may be particularly related to the initial wetting reaction rather than to the longer-term imbibitional rate.

A method of producing ang‐kak (Chinese red rice) in plastic bags by Monascus sp. NP1 was developed. Advantages of the procedure are described. Fermentation of rice of various moisture contents gave results that agreed with previous findings that ang‐kak could be produced only at a relatively low initial moisture level. The mechanism by which the initial substrate moisture content regulated pigmentation was clarified. It was found that glucoamylase activity increased with increase in initial substrate moisture content. Therefore at high moisture content, as high enzyme activity was produced, glucose was rapidly liberated in amounts that inhibited pigmentation. The sugar was then transformed to ethanol. Addition of various amounts of glucose to rice of low moisture content before fermentation confirmed that the sugar at certain concentration had an inhibitory effect on pigmentation.

The swallowing threshold and starch hydrolysis of cooked rice with different moisture contents for human mastication

Mixture of flaxseed meal and corn flour (90/10, w/w) was extruded at a feeding rate of 33.1kg h-1 and different die temperatures (80-160 oC), screw speeds (300-900 rpm), and initial moisture contents(18.8-35.1%) on a co-rotating twin-screw extruder. Extrudates with the maximum removal rate of mucilage of 60.3% and lesser bulk density of 0.647 g cm-3 were obtained at screw speed of 500rpm, temperature of 140C and initial moisture content of 25.1%. The micrographs of the extrudates showed that the greater structure dispersal occurred at higher temperature and lower initial moisture content. Mucilage extracts of enzyme-treated extrudates contained less viscosity than that of unextruded meals. The solubilization of mucilage increased with the increase in soaking time. 82.3% of the removal rate of mucilage was obtained after treatment with Pectinex Smash XXL at enzymatic loading of 200l kg-1 for 6 h.

In this article the technique of a research of correlation dependence between initial and final moisture content of the foam-polymer-mineral (PPM) insulation of an underground heat steel pipe and also results of check of a statistical hypothesis of a type of distribution of a random variable of water absorption of PPM isolation is offered. The nature of distribution established as a result of a research speaks about existence of a limit of opportunities of PPM isolation of a pipe for water absorption – isolation with low initial moisture content is capable to absorb in itself more moisture and vice versa. Absorption of moisture happens until the value of final moisture content of PPM isolation does not reach extremely possible value approximately identical on all volume of isolation.

ABSTRACTA mathematical model for a radial, continuous‐crossflow dryer was modified and used to simulate the drying process in a fixed bed dryer. the predictions of the adapted model were compared with experimental test results for canola drying at the following drying conditions: airflow rates of 0.4 and 0.6 kg/(m2s), inlet air humidity 0.098 and 0.0114 kg/kg of dry air, initial grain moisture content 0.221 and 0.251 kg/kg dry basis. In both tests the inlet drying air temperature was kept at an average of 67.5°C. At the end of canola drying, the mean drying air temperature predicted by our model was within 1°C of the measured temperature and the mean predicted moisture content was within 0.5% of the measured moisture content, dry basis. Also, our model was verified against experimental results for barley published by other authors and against predictions from a published model for barley. the predictions from our model were in good agreement with the published experimental and predicted data. Simulations results for canola and barley drying in the same thickness of a deep bed were compared. Simulations were conducted to investigate the effects of canola properties such as bulk density and dryinig conditions of air such as airflow rate and air humidity on drying in deep beds of canola.

The moisture content of grain is one of the most important factors determining quality, grade, and price and affecting the physical appearance such as the morphology and color of grain kernels. The objective of this study was to evaluate the correlation between moisture content and image characteristics of corn kernels. A simple and inexpensive machine vision system was set up to obtain images and weights of individual kernels of four varieties of corn. The corn kernels were dried from 32% to 12% (wet basis) moisture at low temperature. A total of 23 morphological and 24 color features were extracted from the individual kernel images. Four optimized feature sets (morphological, color, morphological-color, and weight-morphological-color) were used to fit moisture content using a stepwise linear regression. The coefficient of determination (R2) of the linear regression improved considerably with the combination of morphology, color, and weight. The best results, with an R2 of greater than 0.96, were achieved using the optimized weight-morphological-color set for all corn varieties. The results indicate that the machine vision technique proposed in this study has the potential for rapid measurement of grain moisture content in the industry.