Validating the Glass Transition Hypothesis in Explaining Fissure Formation in Rough Rice Kernels During the Drying Process

2021 ◽  
Vol 64 (6) ◽  
pp. 1763-1770
Author(s):  
Zephania Odek ◽  
Terry J. Siebenmorgen ◽  
Griffiths G. Atungulu

HighlightsX-ray imaging allows visualization of the fissuring that occurs at various drying air conditions.Drying air conditions that create severe intra-kernel material state gradients during drying result in kernel fissuring.The glass transition hypothesis was validated for explaining the fissuring of rice kernels during drying.Abstract. Fissured rice kernels tend to break during milling, leading to milling yield reductions. A hypothesis involving changes in material state properties has been proposed to predict kernel fissuring during the drying process. The hypothesis, referred to as the glass transition hypothesis, has been used to explain kernel fissuring during the drying process and has been supported by various milling studies. However, this hypothesis has not been validated from a fundamental fissuring standpoint. In this study, experiments were performed using drying air temperatures of 45°C, 50°C, 55°C, 60°C, and 65°C with relative humidity values that produced equilibrium moisture contents (EMCs) of 6%, 8%, 10%, 12%, and 14%. These EMCs would position the kernel surface at select regions on a rice material state diagram during drying. At the end of active drying, the kernels were tempered for 2 h at the drying air temperature. Fissures were viewed and detected in these kernels using X-ray imaging. Drying air temperature and EMC combinations that caused sufficient portions of the kernel surface to transition to the glassy region while the core remained in the rubbery region caused severe intra-kernel material state gradients. Such intra-kernel material state gradients caused severe fissuring, thus supporting the glass transition hypothesis in explaining fissure formation. At drying air temperature and EMC combinations that did not cause severe intra-kernel material state gradients, severe fissuring was averted, thus further supporting the glass transition hypothesis. Keywords: Glass transition hypothesis, Material state, Rice quality, State diagram, Tempering, X-ray imaging.

2019 ◽  
Vol 1 (1) ◽  
pp. 19-22
Author(s):  
Yus Witdarko

Drying method that is applied in flour manufacturing industry, one of which is pneumatic drying. Variable types of both the properties of the dried material and the conditions of the drying process greatly affect the quality of the results of drying. Water content is an important variable in determining the quality of flour. The purpose of this study was to find the effect of drying air temperature on the moisture content of cassava flour under the conditions of the pneumatic drying process. Drying of cassava flour at desiccant air temperatures of 145oC and 160oC with 2 drying cycles produced a moisture content of 11.3 and 8.7% wb and had fulfilled SNI for flour water content, which was a maximum of 12% wb. The higher the temperature of the drying air, the lower the moisture content.


Holzforschung ◽  
2014 ◽  
Vol 68 (5) ◽  
pp. 591-597 ◽  
Author(s):  
Takashi Tanaka ◽  
Yasuo Kawai

Abstract The objective of this study was the visualization of the migration of a dissolved substance in the liquid water of wood during drying by means of X-ray imaging. The formation of a characteristic deposition pattern has been observed in the course of drying small pieces of sugi soaked in a cesium chloride (CsCl) aqueous solution. Expectedly, CsCl migrated from the inside to the surface and was deposited just below the surface because of the evaporation of water at the evaporation front. At the end of the drying process, the relative concentration of CsCl at the surface of sapwood samples was determined to be 130%–400% of the initial amount of dissolved CsCl, while the CsCl concentration deep inside samples was below 50%. Sapwood accumulated more CsCl than heartwood did, and the CsCl concentration in latewood was higher than in earlywood.


2020 ◽  
Vol 36 (5) ◽  
pp. 639-645
Author(s):  
Zephania R. Odek ◽  
Terry J. Siebenmorgen ◽  
Ashok Saxena

HighlightsDrying rough rice using harsh air conditions causes fissures to appear instantaneously during active drying.For mild drying air conditions, a time interval is required after the cessation of active drying before fissures appear.The majority of fissures due to active drying in rough rice kernels appear after drying has ceased.Abstract. Fissuring of rough rice kernels leads to breakage during milling, which results in head rice yield reductions. While other studies have addressed the fissuring kinetics of milled rice kernels, rice is normally dried and stored as rough rice. Thus, the objective of this research was to study the fissuring kinetics of rough rice kernels during the drying process and to characterize the configuration of the fissures. Rough rice kernels of cultivar CL XL745 with a bulk moisture content of 17% were dried using air at 40°C, 50°C, and 60°C each at relative humidity (RH) levels of 20%, 40%, and 60%. During the drying process (drying, tempering, and subsequent storage), X-ray images of rice kernels were recorded to enumerate fissures. As the drying air temperature was increased, the percentage of fissured kernels increased for all RHs evaluated. Conversely, as RH was increased, the percentage of fissured kernels decreased. Approximately 90% of fissures appeared after drying had ceased, increasing rapidly in the initial 6 h after drying. Kernels dried at high-temperature, low-RH drying air combinations had fissuring occur and appear instantaneously during active drying. In low-temperature drying conditions, fissures did not appear during active drying. Fissuring under such conditions required a time delay after active drying. This study shows the stages of the drying process when fissures appear in rough rice and the durations after active drying when fissures are expected to appear. Keywords: Glass transition, Post-drying, Relative humidity, Rice drying, Temperature, Tempering, X-ray imaging.


2019 ◽  
Vol 41 (4) ◽  
pp. 397-406 ◽  
Author(s):  
Guilherme Cardoso Oba ◽  
André Luís Duarte Goneli ◽  
Tathiana Elisa Masetto ◽  
Cesar Pedro Hartmann Filho ◽  
Karina Laís Leite Sarath Michels ◽  
...  

Abstract: The air temperature used in the drying process can determine the initial physiological quality and storage potential of a seed lot, which is the object of this study. Safflower seeds, harvested at a moisture content of 25.8%, were subjected to drying in an experimental dryer at air temperatures of 40, 50, 60 and 70 °C until reaching a moisture content of 6.6 ± 0.6%. Immediately upon drying and every 60 days after that, up to 240 days of storage under uncontrolled conditions, seed samples were collected to determine physiological quality. Increasing drying air temperature resulted in higher water removal rates, promoting immediate and latent damage to seed physiological quality, evidenced by the reduction in the percentage and speed of root protrusion, first count, and germination, mainly at temperatures of 60 and 70 °C. For the maintenance of safflower seed germination and vigor up to 240 days of storage, it is recommended that drying air temperature does not exceed 40 °C, especially when seeds present moisture contents close to or higher than 25.8% at the drying moment.


Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).


Author(s):  
James F. Mancuso ◽  
William B. Maxwell ◽  
Russell E. Camp ◽  
Mark H. Ellisman

The imaging requirements for 1000 line CCD camera systems include resolution, sensitivity, and field of view. In electronic camera systems these characteristics are determined primarily by the performance of the electro-optic interface. This component converts the electron image into a light image which is ultimately received by a camera sensor.Light production in the interface occurs when high energy electrons strike a phosphor or scintillator. Resolution is limited by electron scattering and absorption. For a constant resolution, more energy deposition occurs in denser phosphors (Figure 1). In this respect, high density x-ray phosphors such as Gd2O2S are better than ZnS based cathode ray tube phosphors. Scintillating fiber optics can be used instead of a discrete phosphor layer. The resolution of scintillating fiber optics that are used in x-ray imaging exceed 20 1p/mm and can be made very large. An example of a digital TEM image using a scintillating fiber optic plate is shown in Figure 2.


Author(s):  
S.J.B. Reed

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.


Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.


Author(s):  
John A. Hunt ◽  
Richard D. Leapman ◽  
David B. Williams

Interactive MASI involves controlling the raster of a STEM or SEM probe to areas predefined byan integration mask which is formed by image processing, drawing or selecting regions manually. EELS, x-ray, or other spectra are then acquired while the probe is scanning over the areas defined by the integration mask. The technique has several advantages: (1) Low-dose spectra can be acquired by averaging the dose over a great many similar features. (2) MASI can eliminate the risks of spatial under- or over-sampling of multiple, complicated, and irregularly shaped objects. (3) MASI is an extremely rapid and convenient way to record spectra for routine analysis. The technique is performed as follows:Acquire reference imageOptionally blank beam for beam-sensitive specimensUse image processor to select integration mask from reference imageCalculate scanning path for probeUnblank probe (if blanked)Correct for specimen drift since reference image acquisition


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