The effect of moisture content on the physico-mechanical properties of some hazelnut varieties

To better understand storage design requirements for hazelnuts, this research determined the physico-mechanical parameters (bulk density, true density, angle of internal friction, static coefficient of friction and dynamic coefficient of friction) of hazelnut varieties Tombul, Badem, Mincane, Çak?ldak and Sivri, for different structural surfaces. Physico-mechanical parameters (bulk density, true density, angle of internal friction, static coefficient of friction and dynamic coefficient of friction) were considered as the dependent variables, and moisture content (8%, 12%, 16%, 20%) as the independent variable. The temperature recorded in the laboratory during the experiments was 24.3 °C. The highest average value for bulk density (520 kg m⁻³) was recorded for the Sivri variety, the highest average value for angle of internal friction (35.4°) for the Badem variety, and the highest average value for true density (870 kg m⁻³) for the Mincane variety. The highest average values for static coefficient of friction (0.411) and the dynamic coefficient of friction (0.287) were recorded for concrete surfaces and the Badem variety.     

Geometric and Mechanical Properties of Mung Bean (Vigna Radiata L.) Grain: Effect of Moisture

In this research, selected geometric and mechanical properties of mung bean grain were evaluated as a function of moisture content. Five levels of moisture content ranging from 7.28 to 17.77% d.b. (dry basis) were used. The average length, width, thickness, arithmetic and geometric mean diameters, sphericity, thousand grain mass and angle of repose ranged from 5.145 to 6.199 mm, 3.760 to 4.474 mm, 3.537 to 4.223 mm, 4.147 to 4.965 mm, 4.090 to 4.893 mm, 0.795 to 0.789, 52.3 to 64.6 g, and 25.87 to 29.38° as the moisture content increased from 7.28 to 17.77% d.b., respectively. The bulk density was found to be decreased from 821.3 to 745.2 kg/m³, whereas the grain volume, true density, porosity, terminal velocity, and projected area were found to be increased from 27.88 to 47.33 mm³, 1230.0 to 1456.7 kg/m³, 30.43 to 46.57%, 4.86 to 5.29 m/s, and 17.48 to 19.26 mm², respectively. There is a 43% increase in surface area from grain moisture content of 7.28 to 17.77% d.b. The static coefficient of friction on various surfaces increased linearly with the increase in moisture content. The rubber as a surface for sliding offered the maximum friction followed by galvanised iron, medium density fibreboard, stainless steel, aluminium and glass sheet. As moisture content increased from 7.28 to 17.77%, the rupture forces values ranged from 67.39 to 39.44 N; 63.86 to 42.18 N, and 53.96 to 41.79 N for thickness (Z axis), length (Y-axis) and width (X-axis), respectively.     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.     

Some physical properties of sugarbeet seed

Various physical properties of sugarbeet seed were determined as a function of moisture content. The lengths of the major, medium and minor axes varied from 4.61 to 5.30, 3.82 to 4.36 and 2.20 to 2.38 mm, respectively, as the moisture content increased from 8.4 to 14.0% d.b. In the same moisture range, the arithmetic and geometric mean diameters increased from 3.54 to 4.02 and 3.38 to 3.80 mm, respectively. Studies on rewetted sugarbeet seed showed that the sphericity decreased from 0.734 to 0.717, whereas thousand seed mass and projected area increased from 12.60 to 13.41 g and 12.1 to 15.6 mm², respectively, with increase in moisture content from 8.4 to 14.0% d.b. The bulk density, true density and porosity decreased from 447 to 418 kg m⁻³, 962 to 851 kg m⁻³ and 53.6 to 50.9%, whereas terminal velocity and angle of repose increased from 5.6 to 6.6 ms⁻¹ and 17.6 to 25.0°, respectively, as the moisture content increased from 8.39 to 14.00% d.b. The static coefficient of friction increased on four structural surfaces namely, rubber (0.687-0.790), plywood (0.480-0.608), galvanised metal (0.392-0.434) and aluminium (0.279-0.388) in the moisture range from 8.4 to 14.0% d.b.     

Physical and mechanical properties of tomato fruits as related to robot’s harvesting

In order to better design, fabricate and control tomato harvesting robot, selected physical properties such as height, diameter, sphericity, surface area, volume, total mass, mass of pericarp and gelatinous matter, bulk density, density of pericarp and gelatinous matter, porosity, projected area, shape factor, and radius of curvature of two cultivar tomato fruits with different locule numbers were mainly investigated by image analysis and water displacement method. Mechanical properties such as friction and rolling resistance coefficients, and rupture energy, rupture force, compressibility, and loading slope of tomato fruits at two loading positions were determined by pull and loading test. Results showed the locule number had a significant effect (P < 0.05) on certain physical and mechanical parameters, such as height, diameter, surface area, rupture force, compressibility, and friction coefficient. The loading position also showed a significant effect (P < 0.05) on certain mechanical parameters, such as compressibility. The obtained properties are closely related to robot’s harvesting.     

Effect of Variety and Initial Moisture Content on Physical Properties of Improved Millet Grains

Physical properties of agricultural materials are important for the design of appropriate equipment and systems for harvesting and post-harvest operations such as cleaning, conveying and storage. The study was conducted to determine the effect of variety and initial moisture content on some physical properties of improved Nigerian millet grains. Improved varieties of millet obtained were conditioned to different moisture contents (10, 20 and 30%) and their physical properties were determined. The grain length, width, thickness and effective geometric mean diameter increased with increasing moisture content irrespective of millet varieties, while aspect ratio (which relates kernel width and length and determines whether grains will slide or roll on their flat surfaces during handling and processing) decreased with increase in moisture content. Static coefficient of friction ranged from 0.44 – 0.99, 0.45 – 0.82, 0.40 – 0.70 and 0.37 – 0.67 for wood, mild steel, galvanized steel and glass respectively. The static coefficients of friction (an important parameter in predicting the lateral pressure on a retaining wall in storage bins or design of bins and hoppers for gravity flow) were found to increase as the moisture content increased. The study showed that variety and initial moisture content had significant effect (P < 0.05) on the physical properties determined. Hence, variety and initial moisture content are critical in the design of equipment for processing, handling and storage of millet grains.     

Assessing mineral composition and morpho-physiological properties of de-hulled einkorn wheat during storage at different moisture levels

In this study were investigated the effects of different moisture levels (4.8, 9.5, 13, 16.7 and 20%, w.b.) during the storage at 10 °C for three months on some mineral compositions and morpho-physiological properties as dimensional (length, width, thickness, arithmetic mean diameter, geometric mean diameter, surface area and volume, sphericity), gravimetric (thousand grain weight, bulk and true densities) and the seed (colour measurement and electrical conductivity) of de-hulled einkorn wheat seeds. Mineral composition of wheat seeds changed with increasing moisture level. In particular, decreases in mineral composition were observed above 16.7% moisture level. Dimensional properties showed increases depending on increased moisture level. It was found that thousand grain weight and true density values increased with increase in moisture level. However, bulk density values were found to decrease with increase in moisture level. The seed colour properties as L*, a*, b*, Chroma, hue angle and Browning index did not change statistically at the end of three months storage with increase at moisture level. The results showed that mineral compositions and functional properties of seeds at moisture level of 9.5% is more suitable than other moisture levels. As a result, high moisture levels during storage can cause degradation of seed quality.     

Moisture-dependent physical properties of dried pomegranate arils

Physical properties of dried pomegranate arils and its variation with moisture content play an important role in designing of equipment for storage, conveying and handling. Physical properties of dried pomegranate arils in the moisture content range of 7–28 % (d.b.) were investigated. Size (GMD), sphericity, weight of the thousand dried arils, true density, bulk density, angle of repose and coefficient of friction at different surfaces (wood, galvanized iron and aluminum) increased, whereas porosity, hardness and toughness decreased with increase in the moisture content. All physical properties except porosity and angle of repose were significantly affected by the change in moisture content at probability level p ≤ 0.01.     

Movement and distribution of adult Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) in stored wheat in response to temperature gradients, dockage, and moisture differences

The movement and distribution of adult Cryptolestes ferrugineus were determined in 100×100×1000 mm wheat columns with or without 5 °C/m temperature gradients (from 27.5±0.2 to 32.5±0.2 °C or at 27.5±0.2 °C) under: (1) 5% and 10% uniform dockage (14.5±0.2% moisture content (m.c.), wet basis); (2) half of the columns with 5% or 10% dockage and the other half without dockage; (3) 12.5%, 14.5% or 16.5% m.c. wheat without dockage; and (4) half of the columns with 12.5% or 14.5% m.c. wheat and the other half with 16.5% m.c. wheat.Adults introduced in the middle of the horizontal wheat columns with or without uniform dockage showed no bias in the direction of net displacement, with the distribution pattern gradually becoming more uniform when time increased from 1 to 144 h. In vertical columns with 0%, 5% and 10% uniform dockage, the adults preferred to move down in the first 24 h; however, they moved up after 24 h. Grain with a high percentage of dockage (10%) decreased beetle movement speed. A low percentage of dockage (5%) did not influence insect movement and distribution. Positive geotaxis was more important than the attraction of dockage.Adults responded to both temperature gradients and moisture differences in columns of wheat with temperature gradients and moisture content differences. The response was different at different moisture conditions. Adults were more sensitive to moisture differences and moved faster in 12.5% m.c. wheat than in 14.5% m.c. wheat. Adults stayed in warmer sections in both high and low moisture grain. At different moisture conditions, adults changed their preference (e.g., preferred high moisture grain in dry grain, and preferred warmer temperature in damp grain).     

PHYSICAL PROPERTIES OF GRAM AS A FUNCTION OF MOISTURE CONTENT

This study was carried out to determine the effect of moisture content on some physical properties of gram. Six levels of moisture content ranging from 10.83 to 31.20 percent (dry basis) were considered for this study. Length, width, thickness, diameter of equivalent sphere, mass of 1000 grains and porosity increased linearly from 7.968 to 8.758 mm, 5.864 to 6.554 mm, 5.713 to 6.359 mm, 6.770 to 8.795 mm, 137.97 to 172.73 g, and 33.17 to 35.85% respectively with the increase of moisture content from 10.83 to 31.20%. The angle of repose increased from 27.03 to 33.27° with the increase of moisture content. Bulk density and true density decreased linearly from 787.31 kg/m³ to 712.61 kg/m³ and 1398 kg/m³ to 1250 kg/m³, respectively. Static coefficient of friction was determined over plywood, galvanized steel, celluloid sheet, and glass sheet. Static coefficient of friction varied from material to material and depended on the roughness and wetness of the true. The highest coefficient of static friction was found over plywood and lowest for glass sheet among the materials tested.     

Diffusion of carbon dioxide through grain bulks

The diffusion coefficient of carbon dioxide (CO₂) through grain bulks was determined using a transient method with the following variables: (1) grain bulk (wheat, barley, and canola); (2) moisture content (m.c.) (dry, damp, and wet conditions); (3) temperature (5°C, 15°C, 25°C, and 40°C); (4) direction of gas flow (upwards, downwards, and horizontal); (5) porosity (two levels for each grain bulk); (6) grain kernel orientation (vertical and horizontal); (7) initial concentration in the gas chamber (20%, 40%, and 60%); and (8) dockage (0%, 4%, 8%, and 12%). The diffusion coefficients of CO₂ through wheat bulks ranged from 5.9×10⁻⁶ to 7.6×10⁻⁶ m² s⁻¹, through barley bulks from 5.1×10⁻⁶ to 8.4×10⁻⁶ m² s⁻¹, and through canola bulks from 3.7×10⁻⁶ to 5.3×10⁻⁶ m² s⁻¹ for the test conditions studied.Increasing the m.c. decreased diffusion coefficients. An increase in temperature generally increased the diffusion coefficient of CO₂. Diffusion in the downward direction resulted in higher diffusion coefficients. No significant difference in diffusion coefficients was observed between the upward and horizontal directions of flow. An increase in porosity resulted in higher diffusion coefficients. The upward diffusion coefficient of CO₂ was higher for vertical grain kernel orientation than for horizontal kernel orientation for wheat and barley but for canola, the difference between the two kernel orientations was not significant. There was no significant difference in diffusion coefficients for different initial gas concentrations. The diffusion coefficient increased linearly as the dockage was increased.The amount of CO₂ absorbed by barley and canola increased with an increase in m.c. in polynomial fashion. There was no significant difference in the sorption of CO₂ by barley and canola when the temperature of the grain was changed from 15°C to 40°C.     

PHYSICAL and THERMAL PROPERTIES of GORGON NUT

Bulk density, true density, angle of repose, coefficient of friction on metal surfaces, specific heat, thermal diffusivity and conductivity of gorgon nut were determined using standard techniques for different sizes of nuts at moisture contents and temperatures ranging from 15 to 60% (dry basis) and 25 to 55C, respectively. the physical properties varied quadratically with moisture content. Specific heat increased with moisture and temperature but decreased with the size of the nut; whereas, the thermal diffusivity showed a reverse trend. Thermal conductivity increased with moisture content but did not follow any trend with temperature within the range of the study. the physical and thermal properties data at various moisture contents and temperatures were used to develop equations for different sizes of gorgon nuts.     

Effects of moisture content and compression axis on mechanical properties of Shea kernel

Some mechanical properties of Shea kernel were investigated in this study. The kernels were divided into two categories sizes namely: small size kernel (SSK) and large size kernel (LSK) and the properties investigated were: rupture force, deformation at rupture and energy consumed at rupture. The tests were carried out at a deformation rate of 50 mm/min and four moisture content levels of 25.9%, 11.60%, 6.88%, 4.98% (db) for SSK and 11.19%, 6.21%, 5.78% and 2.77% (db) for LSK. The variations in these properties were observed considering the effects of moisture content and compression axes on them as the kernels were air-dried. Sample kernels were compressed along the orthogonal axes corresponding to major axes (length), intermediate axes (width) and minor axes (thickness) of Shea kernel. Some physical characteristics of Shea kernel such as dimensions, geometric mean diameter and mass were also evaluated. Results showed that generally, rupture force, deformation and energy at rupture decreased as moisture content decreased. The regression models that best fitted the relationships were polynomial functions of the second order. The highest and lowest forces for Shea kernel to rupture were those through the minor axis (thickness) and major axis (length) respectively. These properties are often required for the design of transportation, storage and grading/sorting machines and other post harvest machines for Shea kernel.     

PHYSICAL AND AERODYNAMIC PROPERTIES OF MAKHANA

Makhana is a popped kernel of gorgon nut (Euryale ferox) and is considered a delicious food item in India. It is, presently, sorted, graded and processed manually. To develop any kind of mechanized system for these purposes, physical data are required and thus, test weight, bulk density, true density, porosity, angle of repose and coefficient of friction of different grades of makhana were determined using standard techniques at moisture contents ranging from 5 to 20% (dry basis). The data were used to develop correlation equations that predict these physical properties as a function of moisture content of makhana. The spatial dimensions and aerodynamic properties were also determined. The average diameter of makhana varied between 18.4 mm to 12.4 mm with the sphericity between 0.581 to 0.967; and other physical properties varied quadratically with moisture content. The terminal velocity and drag coefficient of makhana at 8% moisture content (dry basis) varied between 4.48 to 6.10 m/s and 0.62 to 1.06, respectively.     

不同含水量下黔江肾豆加工物理特性研究

主要研究了含水量在5.0%至35.0%范围内7个梯度水平下的黔江肾豆的各项物理特性,以期为黔江肾豆的实际生产加工、后续的开发研究及其他研究分析提供所需的籽粒物理性质数据参考。主要研究测定不同含水量下黔江肾豆的各项物理性质,包括:粒径、圆球度、体积、表面积、千粒重、容重、真实密度、孔隙率、休止角、静摩擦系数等。结果表明,除圆球度外,各项物理性质受水分含量影响均显著。随着含水量的增加,容重值降低;摩擦系数随含水量增加而增大,同时又与接触表面性质相关,木质横纹>木质直纹>钢>铝;其他各物理特性值均升高。     

Physical Properties of Guar Seeds

A study on the guar seeds (Cyamopsis tetragonoloba) was performed to investigate the effect of moisture content on the selected physical properties. Moisture contents of seeds were varied from 5.2% to 25.0%, dry basis (d.b.). Seed geometric parameters, such as average length, width, thickness, geometric-mean diameter, surface area, volume, increased but sphericity decreased with increase in moisture content. The 1,000-seed mass increased linearly with moisture content. Bulk density of guar seeds decreased linearly when moisture content was raised from 5.2% to 25.0% d.b. On the other hand, true density decreased till moisture content was increased up to 20%. Further increase in seed moisture resulted in increased true density, which has not been observed in other food grains. The porosity decreased till seed 15.3% moisture and then increased with further addition of moisture. Angle of repose, coefficients of static friction on three different surfaces (plywood, mild steel, and galvanized iron), and terminal velocity increased linearly with seed moisture content.     

Estimating deoxynivalenol contents of wheat samples containing different levels of Fusarium-damaged kernels by diffuse reflectance spectrometry and partial least square regression

Fusarium head blight is a fungal disease causing yield losses and mycotoxin contamination in wheat and other cereals. Wheat kernels (cultivar Ritmo) were sampled in 2001, 2002, 2003, and 2006 and Fusarium-damaged kernels were separated from sound grain based on visual assessment. Subsequently, grain lots containing 0, 20, 40, 60, 80, and 100% of damaged kernels were compiled. Each lot was split and the spectrometric reflectance (wavelengths 350-2500 nm) was measured using subgroup one, while the concentration of the mycotoxin deoxynivalenol (DON) was determined by high-performance liquid chromatography in subgroup two. DON concentrations in batches classified as sound were not significantly different from 0. Estimating DON contents from the percentage of Fusarium-damaged kernels was impeded by vast variability, resulting in a coefficient of determination of 0.49. Using spectrometric data subjected to partial least square regression allowed estimating DON contents with higher accuracy, in particular at elevated percentages of damaged kernels. The coefficient of determination was 0.84 for the relationship between DON contents estimated based on spectrometric data and the DON contents measured. The intercept of a regression line fitted through a plot of estimated versus measured DON contents was 0.89 ± 3.61 mg/kg. Since intercept + standard error was larger than the actual legal limit (1.25 mg DON per kg dry grain in the European Union), the spectrometric procedure was still not precise enough to allow a reliable separation of grain samples with DON contents below 1.25 mg/kg from samples with DON contents above the limit. However, spectrometric data also allowed estimating the DON content of the average damaged kernel within a given lot composed of sound and damaged kernels, which is probably the reason for the reduction of the fraction of unexplained variance by 35% compared to the visual approach and illustrates that spectrometric approaches can make a contribution to reducing DON contents of wheat grain.     

Moisture-Dependent Physical Properties of Kola Nut (Cola nitida) Seed

This study was carried out to determine the effect of moisture content on some physical properties of kola nut seed. Four moisture levels ranging from 47.48 to 61.4 % wet basis (w.b.) was considered. Results showed that there was linear increase in the mean length, width, thickness, geometric mean diameter, surface area, volume, sphericity, aspect ratio, 1,000 nut mass, bulk and true densities, and static coefficient of friction at different surfaces (mild steel and wood) by 3.58, 3.96, 6.29, 4.98, 10.72, 16.87, 1.54, 1.50, 26.23, 11.50, 7.27, and 17.86 to 23.53 %, respectively, with increase in moisture content from 47.48 to 61.4 % (w.b.). Furthermore, the angle of repose increased by 17.45 % while the porosity decreased by 3.85 % with increase in moisture content.     

Strength and Frictional Properties of Popcorn Kernel as Affected by Moisture Content

Strength properties and dynamic coefficient of friction of popcorn kernels were evaluated as a function of moisture content in the range of 7.78–16.72 g/100 g dry solids. In order to determine strength properties of the kernels that are in terms of deformation at rupture point, rupture force, energy absorbed, hardness, and toughness of the popcorn kernels were quasi-statically loaded between two parallel plates. To determine frictional properties, friction tests were performed on aluminum, steel, and fiberglass surfaces. The values related to the strength properties, in general, decreased as the moisture content increased. On the other hand, the dynamic coefficient of friction of the popcorn kernels increased with increasing moisture content.     

Insect population dynamics in commercial grain elevators

Data were collected in 1998-2002 from wheat stored in commercial grain elevators in south-central Kansas. Bins at these elevators had concrete walls and were typically 6-9 m in diameter and 30-35 m tall. A vacuum-probe sampler was used to collect grain samples in the top 12 m of the wheat in each bin. The primary insect species found in the wheat samples were: Cryptolestes ferrugineus, Rhyzopertha dominica, and Tribolium castaneum. In the top 3.7 m of grain, R. dominica, C. ferrugineus, T. castaneum and Sitophilus oryzae made up 44, 36, 19 and 1% of the insects found in the samples, respectively. From 3.8 to 12.2 m, R. dominica, C. ferrugineus, T. castaneum and S. oryzae were present at 84, 8, 8, and 1%, respectively. The most prevalent species also changed over time. In June, the start of wheat harvesting and storage in Kansas, insect density was low in the bins. At this time, C. ferrugineus was the most common insect, and it was found mostly in the top grain sample (0-1.2 m). In September through November, C. ferrugineus and R. dominica were at similar densities; however, from February to March, R. dominica was more common.Generally, insect density was greatest at the top and decreased with grain depth. Very few insects were found in samples collected from greater than 12 m (most of the bins contained grain to depths of 24-36 m). Insect density for all species increased rapidly from June through October. During this period less than 20% of the bins had economically significant insect densities (>2 insects/kg). From October until February, the average insect density remained fairly constant but it was greatly reduced in April, May, and June. Bins that had insect densities >2 insects/kg tended to be located adjacent to other heavily infested bins.