Angle of Repose

The physical properties of bambara groundnut and other grains and seeds are necessary for the design of equipment to handle, transport, process and store the crop. The physical properties of bambara groundnut have been evaluated as a function of grain moisture content varying from 5% to 35% (wb). In this moisture range, grain length, width, thickness and geometric diameter increased from 10.5 to 14.65 mm, 9.48 to 11.65 mm, 8.50 to 10.90 mm and 9.65 to 12.55 mm respectively; the grain surface area and volume increased from 304 to 495 mm2 and from 425 to 900 mm3, respectively; the sphericity decreased from 0.90 to 0.87; the 1000-seed mass increased from 500.2 to 800.6 g; true and bulk densities decreased from 1.285 to 1.160 g/cm3 and from 0.795 to 0.696 g/cm3, respectively; the porosity and angle of repose increased with increase in moisture content up to 43.8% and 23.5°, respectively, at 20% moisture content; the sphericity decreased from 0.895 at 5% moisture content to 0.820 at 35% moisture content. The coefficient of static friction increased from 0.39 to 0.66, 0.29 to 0.58 and 0.25 to 0.49 for plywood, galvanised iron and aluminium, respectively.

Physical properties of Salvia hispanica L. seeds were investigated and their application was also discussed. Physical properties were assessed for white and dark seed separately, except for the angle of repose and static coefficient of friction, which were determined for the seed mixture. The mean moisture content was 7.0% (dry basis). The average for the three characteristic dimensions, length, width and thickness was 2.11, 1.32 and 0.81 mm for dark seeds and 2.15, 1.40 and 0.83 mm for white seeds, respectively. The bulk density, true density and the porosity were between 0.667 and 0.722 g cm−3, 0.931 and 1.075 g cm−3, and 22.9 and 35.9%, respectively. The equivalent diameter ranged from 1.32 to 1.39 mm. The volume of single grain and sphericity ranged between 1.19 and 1.42 mm3, and 62.2 and 66.0%, respectively. The geometric mean diameter ranged between 1.31 and 1.36 mm for dark and white chia seeds, respectively. This parameter could be used for the theoretical determination of seed volume and sphericity. One thousand seed mass averaged 1.323 g for dark seeds, and 1.301 g for white seed. The angle of repose varied between 16° and 18° whereas the value of static coefficient of friction was 0.28 on galvanized sheet and 0.31 on mild steel sheet.

Browntop millet (Urochloa ramose L.) known as 'korale' in Karnataka is an annual warm-season grass often used as a forage crop gaining importance because of its nutritional qualities. Very fewer researches have been done so far on the millet. The research was conducted to determine the physical properties of the browntop millet. The physical properties were determined at moisture content 11.2 ± 0.16 (w.b). The mean values of length, width and thickness of the browntop millet were found to be 3.00 ± 0.21, 1.79 ± 0.10 and 1.15 ± 0.09 mm, respectively. The geometric mean diameter and arithmetic mean diameter were 1.82 ± 0.09 and 1.99 ± 0.1 mm, respectively. The mean weight of 1000 browntop millet seeds was 3.42 ± 0.14 g. The bulk density and true density were 601.17 ± 4.08 and 1305.47±95.5 kg/m 3 , respectively. The mean porosity, aspect ratio and sphericity were found to be 53.74 ± 3.23, 58.58 ± 3.84 and 59.82 ± 2.60%, respectively. The shape of the browntop millet was oval. The angle of repose was 27°47' ± 0.21 and the coefficient of friction for the three surfaces namely, Glass, Aluminum and Wooden Sheets were 0.62 ± 0.0009, 0.59 ± 0.0051 and 0.6 ± 0.0063, respectively. The terminal velocity was 7.2 m/sec. The tristimulous colour values (L*, a* and b*) were found to be 60.45 ± 0.44, 3.78 ± 0.06 and 14.71 ± 0.33, respectively. Hence this study helps agricultural and food engineers, designers, scientists and processors towards design of equipment and efficient process for browntop millet grain processing.

Problem statement: The measurement of powder flowability is a major concern for most industrial processes that deal with the handling of bulk solids as raw materials, intermediates, or products. Approach: The influence of particle size on the flowability of silica gel was investigated using aerated and non-aerated methods. The aerated method involved the measurement of the Hausner Ratio (HR) and Angle Of Repose (AOR) using a Hosokawa Powder Tester (PT-S), while
the non-aerated method involved a Cohesion Index (CI) measurement based on a Stable Micro Systems TA.XT Plus texture analyzer. The mean size diameters of the fine and coarse powders used in this work were 9.4 and 60 μm, with densities of 2.1262 and 2.1290 gm cm-3, respectively. The experiments were conducted immediately after drying with a range of sizes of the chosen powder. Results: The three measured parameters confirmed the general expectation that the fine powders are cohesive and the coarse powders are free-flowing. The HR values indicated that the mixture was a free-flowing one above the 40 μm size. A transition in flowability occurred when the size was between 28 and 40 μm, while the mixture became cohesive when the particle size was below 28 μm. All three
of the flowability indicators corresponded well with each other, signifying that the selected indicators correctly predicted the flowability. Conclusion: The new non-aerated method, where CI was measured, was proven to be a reliable indicator in predicting flow characteristics.

http://www.thescipub.com/abstract/10.3844/pisp.2010.16.21

U ovom završnom radu objašnjen je način određivanja prirodnog kuta sipanja materijala pomoću trodimenzionalnih modela dobivenih iz fotografija. U tu svrhu provedena su laboratorijska ispitivanja, a primijenjena je metoda cilindra zbog jednostavnosti, dovoljne preciznosti i pouzdanosti. U radu je opisana razlika između dinamičkog i statičkog kuta sipanja, te primjena kuta sipanja u rudarske svrhe. Detaljno je objašnjena izrada modela stošca iz fotografija u programu Agisoft PhotoScan i postupak dobivanja kuta sipanja.

Lignocellulosic biomass feedstock such as corn stover, the residues left on the field after corn grain harvest, has been studied as one of the renewable feedstocks to be used for fuel ethanol conversion in the near future. The primary objective of this work was to determine the angle of repose (AoR) of bulk corn stover particles prepared to four particle

Problem statement: The measurement of powder flowability is a major c oncern for most industrial processes that deal with the handling of bulk solids as raw materials, intermediates, or products. Approach: The influence of particle size on the flowability of silica gel was investigated using aerated and non-aerated methods. The aerated method involved the measurement of the Hausner Ratio (HR) and Angle Of Repose (AOR) using a Hosokawa Powder Tester (PT-S), while the non-aerated method involved a Cohesion Index (CI) measurement based on a Stable Micro Systems TA.XT Plus texture analyzer. The mean size diameters of the fine and coarse powders used in this work were 9.4 and 60 µm, with densities of 2.1262 and 2.1290 gm cm -3 , respectively. The experiments were conducted immediately after drying with a range of sizes of the chosen powder. Results: The three measured parameters confirmed the general expectation that the fine powders are cohesive and the coarse powders are free-flowing. ...

In-line near-infrared spectroscopy (NIR) spectra were acquired and analyzed to assess the relationship between physical and chemical properties of voiding powders and their spectral changes. NIR spectra were obtained for powders voiding from a conical glass funnel while the powder flow was recorded with a digital camera. Two different approaches using in-line NIR spectra were developed to measure the flow interruptions in the powder voiding process. The first approach uses the noise in the spectra and the second is based on the baseline changes. The new method was also used to evaluate the effects of humidity on the flow of microcrystalline cellulose samples and to evaluate the effect of mixing method on the flow properties of the blends obtained. The method described may be applied to other applications that involve powder flow, and the same spectra may be used to determine drug concentration.

In the past three decades, studies on the mechanisms of interface shear in a variety of geotechnical problems have drawn significant attention. In response to the urgent need in understanding the shear behavior at particulate-continuum interfaces, several experimental and numerical studies on the effects of interface properties and loading conditions have been conducted at the Georgia Institute of Technology. To expand these studies, the current research focuses on developing numerical tools to study the response of interface systems under pre-sheared soil conditions. In particular, how does cone penetration affect the shear behavior at soil-penetrometer interface will be investigated in the current study. To comprehensively understand the interface behavior, the properties of the contacting components—soil and continuum surface—shall be extensively studied. Inherited from the novel design of the multi-friction attachment (MFA), the surface roughness of the continuum surface in the ...

Abstract: Information on physical properties of broiler chickens diets is not available in literatures and such information is important for design and construction of poultry equipment s . Some physical properties of starter, grower and finisher diet of broiler chickens, namely: gravimetrical (bulk density, true density and porosity) and frictional properties (coefficient of friction filling angle of repose, empting angle of repose and pouring angle of repose) were studied. Effect of height of falling diets to the containers at 150, 250 and 350 mm and volume of the containers at 500, 600, 1 , 100 and 2 , 000 m L on bulk density and porosity of diets were studied. Results indicated that true density of the starter; grower and finisher diets were 1 , 442.574, 1 , 512.694 and 1 , 541.320 kg m 3 , respectively. A comparison between the three levels of height of falling for three diets indicated that with increasing height of falling, bulk density were increased and porosity were decrea...