scholarly journals Conveyor-Belt Dryers with Tangential Flow for Food Drying: Mathematical Modeling and Design Guidelines for Final Moisture Content Higher Than the Critical Value

Inventions ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Dario Friso
Keyword(s):  
Mathematical Modeling ◽  
Moisture Content ◽  
Rational Design ◽  
Conveyor Belt ◽  
Design Guidelines ◽  
Final Moisture Content ◽  
Temperature Sensitive ◽  
Optimized Design ◽  
Tangential Flow ◽  
Product Flow

The mathematical modeling presented in this work concerns the conveyor-belt dryer with the tangential flow of air with respect to food. This dryer, if operating in co-current, has the advantage of well preserving the organoleptic and nutritional qualities of the dried product. In fact, it has a low air temperature in the final stretch where the product has low moisture content and is therefore more temperature sensitive. It is a bulkier dryer than the continuous through-circulation conveyor dryer with a perforated belt. The latter is therefore more frequently used and has received greater study attention from researchers and designers of the industry. With the aim to propose guidelines for a rational design of the conveyor-belt dryer with tangential flow, a mathematical model was developed here through the differentiation of the drying rate equation followed by its integration performed along the dryer belt. Consequently, and with the assumption that the final moisture content XF of the product is higher than the critical moisture content XC, the relationships between the intensive quantities (temperatures, humidity and enthalpies), the extensive quantities (air and product flow rates) and the dimensional ones (length and width of the belt), were obtained. Finally, on the basis of these relationships, the rules for an optimized design for XF > XC were obtained and experimentally evaluated.

scholarly journals Mathematical Modelling of Conveyor-Belt Dryers with Tangential Flow for Food Drying up to Final Moisture Content below the Critical Value

Inventions ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 43
Author(s):  
Dario Friso
Keyword(s):  
Mathematical Modeling ◽  
Moisture Content ◽  
Flow Rate ◽  
Rational Design ◽  
Cross Flow ◽  
Conveyor Belt ◽  
Final Moisture Content ◽  
Optimized Design ◽  
Tangential Flow ◽  
Product Flow

This work presents the mathematical modeling of the conveyor-belt dryer with tangential flow operating in co-current, which has the advantage of improving the preservation of the organoleptic and nutritional qualities of the dried food. On the one hand, it is a more cumbersome dryer than the perforated cross flow belt dryer but, on the other hand, it has a low air temperature in the final section where the product has a low moisture content and, therefore, it is more heat sensitive. The results of the mathematical modeling allowed a series of guidelines to be developed for a rational design of the conveyor-belt dryer with tangential flow for the specific case of the moisture content of the final product XF lower than the critical one XC (XF < XC). In fact, this work follows a precedent in which a mathematical model was developed through the differentiation of the drying rate equation along the dryer belt with the hypothesis that the final moisture content XF of the product was higher than the critical one XC. The relationships between the extensive quantities (air flow rate and product flow rate), the intensive quantities (temperatures, moisture content and enthalpies) and the dimensional ones (length and width of the belt) were then obtained. Finally, based on these relationships, the rules for an optimized design for XF < XC were obtained.

scholarly journals Conveyor-Belt Dryers with Tangential Flow for Food Drying: Development of Drying ODEs Useful to Design and Process Adjustment

Inventions ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Dario Friso
Keyword(s):  
Moisture Content ◽  
Conveyor Belt ◽  
Design Guidelines ◽  
Final Moisture Content ◽  
Optimized Design ◽  
Tangential Flow ◽  
Process Adjustment ◽  
Mathematical Investigation ◽  
Adjustment System ◽  
The Relationship

The mathematical investigation presented in this paper concerns the conveyor-belt dryer with tangential flow operating in co-current. This dryer is bigger than the continuous through-circulation conveyor dryer but has the advantage of better preserving the organoleptic and nutritional qualities of the dried product. In a previous work a mathematical modeling of the conveyor-belt dryer with tangential flow was carried out to offer guidelines for its optimized design. The last of those design guidelines indicated the need for an optimized adjustment of the dryer to ensure the constant maintenance of the final moisture content of the product. The fast and very precise measurement of the moisture content as the first step in the feedback chain was therefore necessary. Considering the difficulty of this type of measurement, two specific ordinary differential equations (ODEs) were obtained with the mathematical investigation of this work. Their solution became a relationship between the final moisture content of the product, the outlet air temperature, and other quantities that could be easily implemented in an automatic dryer control system. Therefore, the fast and accurate and much less expensive measurement of the temperature of the air leaving the dryer, owing to the relationship found, replaces the measurement of moisture content for the adjustment system. The experimental verification of the relationship highlighted the need to introduce a modification by which the relationship was finally validated.

scholarly journals Temperature-Sensitive Mutants in the Influenza A Virus RNA Polymerase: Alterations in the PA Linker Reduce Nuclear Targeting of the PB1-PA Dimer and Result in Viral Attenuation

2015 ◽  
Vol 89 (12) ◽  
pp. 6376-6390 ◽  
Author(s):  
Bruno Da Costa ◽  
Alix Sausset ◽  
Sandie Munier ◽  
Alexandre Ghounaris ◽  
Nadia Naffakh ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Rna Polymerase ◽  
Nuclear Import ◽  
Influenza A ◽  
Rational Design ◽  
Hot Spot ◽  
Temperature Sensitive ◽  
Nuclear Targeting ◽  
Virus Rna ◽  
Endonuclease Domain

ABSTRACTThe influenza virus RNA-dependent RNA polymerase catalyzes genome replication and transcription within the cell nucleus. Efficient nuclear import and assembly of the polymerase subunits PB1, PB2, and PA are critical steps in the virus life cycle. We investigated the structure and function of the PA linker (residues 197 to 256), located between its N-terminal endonuclease domain and its C-terminal structured domain that binds PB1, the polymerase core. Circular dichroism experiments revealed that the PA linker by itself is structurally disordered. A large series of PA linker mutants exhibited a temperature-sensitive (ts) phenotype (reduced viral growth at 39.5°C versus 37°C/33°C), suggesting an alteration of folding kinetic parameters. Thetsphenotype was associated with a reduced efficiency of replication/transcription of a pseudoviral reporter RNA in a minireplicon assay. Using a fluorescent-tagged PB1, we observed thattsand lethal PA mutants did not efficiently recruit PB1 to reach the nucleus at 39.5°C. A protein complementation assay using PA mutants, PB1, and β-importin IPO5 tagged with fragments of theGaussia princepsluciferase showed that increasing the temperature negatively modulated the PA-PB1 and the PA-PB1-IPO5 interactions or complex stability. The selection of revertant viruses allowed the identification of different types of compensatory mutations located in one or the other of the three polymerase subunits. Twotsmutants were shown to be attenuated and able to induce antibodies in mice. Taken together, our results identify a PA domain critical for PB1-PA nuclear import and that is a “hot spot” to engineertsmutants that could be used to design novel attenuated vaccines.IMPORTANCEBy targeting a discrete domain of the PA polymerase subunit of influenza virus, we were able to identify a series of 9 amino acid positions that are appropriate to engineer temperature-sensitive (ts) mutants. This is the first time that a large number oftsmutations were engineered in such a short domain, demonstrating that rational design oftsmutants can be achieved. We were able to associate this phenotype with a defect of transport of the PA-PB1 complex into the nucleus. Reversion substitutions restored the ability of the complex to move to the nucleus. Two of thesetsmutants were shown to be attenuated and able to produce antibodies in mice. These results are of high interest for the design of novel attenuated vaccines and to develop new antiviral drugs.

Effects of Drying Conditions, Final Moisture Content, and Degree of Milling on Rice Flavor

1997 ◽  
Vol 74 (5) ◽  
pp. 566-570 ◽  
Author(s):  
Elaine T. Champagne ◽  
Karen L. Bett ◽  
Bryan T. Vinyard ◽  
Bill D. Webb ◽  
Anna M. McClung ◽  
...  
Keyword(s):  
Moisture Content ◽  
Final Moisture Content ◽  
Degree Of Milling ◽  
Drying Conditions ◽  
Rice Flavor

Stability of Thiamine and Riboflavin During Extrusion Processing of Triticale

1976 ◽  
Vol 39 (4) ◽  
pp. 244-245 ◽  
Author(s):  
G. BEETNER ◽  
T. TSAO ◽  
A. FREY ◽  
K. LORENZ
Keyword(s):  
Moisture Content ◽  
Multiple Regression ◽  
Temperature Effects ◽  
Initial Moisture Content ◽  
Final Moisture Content ◽  
Whole Grain ◽  
Moisture Contents ◽  
Extrusion Processing ◽  
Nozzle Size ◽  
The Relationship

Triticale kernels were extruded using a Brabender Plasticorder extruder with ¾-inch rifled barrel and 1:1 flight depth ratio screw. Whole grain samples were extruded at initial moisture contents of 15, 20, and 25%. Debranned samples were extruded at an initial moisture content of 22%. Barrel temperatures of 350, 400, and 450 F and nozzle openings of 1/8 inch and 1/16 inch were used. The products were analyzed for thiamine and riboflavin content. Results were corrected for final moisture content and expressed as fraction retained. A multiple regression was done to determine the relationship between independent and derived variables, and the retention. Riboflavin retention was correlated simply as a function of barrel temperature. Thiamine retention of the debranned material was correlated as a function of nozzle size and barrel temperature. Thiamine retention of the whole grain samples was correlated for nozzle size, first and second order temperature effects, and confounding between nozzle size and temperature.

scholarly journals Enhanced stability and polyadenylation of select mRNAs support rapid thermogenesis in the brown fat of a hibernator

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Katharine R Grabek ◽  
Cecilia Diniz Behn ◽  
Gregory S Barsh ◽  
Jay R Hesselberth ◽  
Sandra L Martin
Keyword(s):  
Mathematical Modeling ◽  
Low Temperatures ◽  
Temperature Sensitive ◽  
Molecular Pathways ◽  
Physiological Regulation ◽  
Brown Adipose ◽  
Activity Cycles ◽  
Intense Activity ◽  
Enhanced Stability ◽  
Periodic Arousal

During hibernation, animals cycle between torpor and arousal. These cycles involve dramatic but poorly understood mechanisms of dynamic physiological regulation at the level of gene expression. Each cycle, Brown Adipose Tissue (BAT) drives periodic arousal from torpor by generating essential heat. We applied digital transcriptome analysis to precisely timed samples to identify molecular pathways that underlie the intense activity cycles of hibernator BAT. A cohort of transcripts increased during torpor, paradoxical because transcription effectively ceases at these low temperatures. We show that this increase occurs not by elevated transcription but rather by enhanced stabilization associated with maintenance and/or extension of long poly(A) tails. Mathematical modeling further supports a temperature-sensitive mechanism to protect a subset of transcripts from ongoing bulk degradation instead of increased transcription. This subset was enriched in a C-rich motif and genes required for BAT activation, suggesting a model and mechanism to prioritize translation of key proteins for thermogenesis.

Exergy and Energy Analysis, Drying Kinetics and Mathematical Modeling of White Mulberry Drying Process

2014 ◽  
Vol 10 (2) ◽  
pp. 269-280 ◽  
Author(s):  
Hosain Darvishi ◽  
Mohammad Zarein ◽  
Saied Minaei ◽  
Hamid Khafajeh
Keyword(s):  
Mathematical Modeling ◽  
Energy Efficiency ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Microwave Power ◽  
Specific Energy Consumption ◽  
Drying Kinetics ◽  
Improvement Potential ◽  
White Mulberry

Abstract The energy and exergy analysis, drying characteristics and mathematical modeling of the thin-layer drying kinetics of white mulberry using microwave drying were investigated. Results indicated that values of exergy efficiency (33.63–57.08%) were higher than energy efficiency (31.85–55.56%). Specific energy consumption increased with increasing microwave power while improvement potential decreased. The specific energy consumption and improvement potential varied from 3.97 to 6.73 MJ/kg water and 0.71 to 2.97 MJ/kg water, respectively. Also, energy efficiency decreased with decrease in moisture content and microwave power level. The best exergy and energy aspect was obtained by drying at 100 W microwave power. Drying took place mainly in warming up, constant rate and falling rate periods. The Page model showed the best fit to experimental drying data. Effective diffusivity increased with decreasing moisture content and increasing microwave power. It varied from 1.06 × 10−8 to 3.45 × 10−8 m2/s, with an energy activation of 3.986 W/g.

Temperature and moisture controls on non-growing season CO2 emissions in laboratory incubations with soils from northern peatlands

2021 ◽  
Author(s):  
Eunji Byun ◽  
Fereidoun Rezanezhad ◽  
Linden Fairbairn ◽  
Nathan Basiliko ◽  
Jonathan Price ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Saturation ◽  
Carbon Sink ◽  
Growing Season ◽  
Temperature Sensitive ◽  
Near Surface ◽  
Soil Microbial ◽  
Carbon Budget Model ◽  
Peat Deposits ◽  
Northern High Latitude

&lt;p&gt;Canada has extensive peat deposits in northern high latitude wetlands and permafrost ecosystems. Peat accumulation represents a natural long-term carbon sink attributed to the cumulative excess of growing season net ecosystem production over non-growing season net mineralization. However, near-surface peat deposits are vulnerable to climate change and permafrost landscape transition. One specific concern is a potential rapid increase in the non-growing season carbon loss through enhanced organic matter mineralization under a warming climate. Our experimental study explores the response of peat CO&lt;sub&gt;2&lt;/sub&gt; exchanges to (1) temperature, using the conventional &lt;em&gt;Q&lt;sub&gt;10&lt;/sub&gt;&lt;/em&gt; parameter, and (2) moisture content. The observed responses are expected to reflect, at least in part, differential soil microbial adaptations to varying wetland conditions, across two northern ecoclimatic zones. Laboratory incubations were carried out with shallow peat samples from different depths collected at seven Canadian wetland sites and adjusted to five moisture levels. For each subsample (varying by site, depth and moisture content), CO&lt;sub&gt;2&lt;/sub&gt; fluxes were measured at 12 sequential temperature settings from -10 to 35&amp;#730;C. For each subsample, the data were fitted to an exponential equation to derive a &lt;em&gt;Q&lt;sub&gt;10&lt;/sub&gt;&lt;/em&gt; value. In general, boreal peat samples were more temperature sensitive than temperate peat. The optimum moisture level for CO&lt;sub&gt;2&lt;/sub&gt; release was determined for all the subsamples and related to variations in wetland vegetation and landform types. As a general trend, increasing water saturation reduced the CO&lt;sub&gt;2&lt;/sub&gt; release rate from a given subsample. We further tested a flexible curve-fitting equation, as recently proposed on a theoretical basis, to recompile the data by ecoclimatic peat type and to account for the non-growing season dynamics. These findings will contribute to Canada&amp;#8217;s national carbon budget model by guiding the development and calibration of the peatland module.&lt;/p&gt;

scholarly journals Linking Atmospheric Rivers and Warm Conveyor Belt Airflows

2019 ◽  
Vol 20 (6) ◽  
pp. 1183-1196 ◽  
Author(s):  
H. F. Dacre ◽  
O. Martínez-Alvarado ◽  
C. O. Mbengue
Keyword(s):  
Moisture Content ◽  
Cold Front ◽  
Moisture Flux ◽  
Conveyor Belt ◽  
Water Vapor Transport ◽  
Extratropical Cyclones ◽  
High Moisture Content ◽  
High Moisture ◽  
Atmospheric Rivers ◽  
Cyclone Center

Abstract Extreme precipitation associated with extratropical cyclones can lead to flooding if cyclones track over land. However, the dynamical mechanisms by which moist air is transported into cyclones is poorly understood. In this paper we analyze airflows within a climatology of cyclones in order to understand how cyclones redistribute moisture stored in the atmosphere. This analysis shows that within a cyclone’s warm sector the cyclone-relative airflow is rearwards relative to the cyclone propagation direction. This low-level airflow (termed the feeder airstream) slows down when it reaches the cold front, resulting in moisture flux convergence and the formation of a band of high moisture content. One branch of the feeder airstream turns toward the cyclone center, supplying moisture to the base of the warm conveyor belt where it ascends and precipitation forms. The other branch turns away from the cyclone center exporting moisture from the cyclone. As the cyclone travels, this export results in a filament of high moisture content marking the track of the cyclone (often used to identify atmospheric rivers). We find that both cyclone precipitation and water vapor transport increase when moisture in the feeder airstream increases, thus explaining the link between atmospheric rivers and the precipitation associated with warm conveyor belt ascent. Atmospheric moisture budgets calculated as cyclones pass over fixed domains relative to the cyclone tracks show that continuous evaporation of moisture in the precyclone environment moistens the feeder airstream. Evaporation behind the cold front acts to moisten the atmosphere in the wake of the cyclone passage, potentially preconditioning the environment for subsequent cyclone development.

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