1. |
- Ahrné, Lilia, et al.
(författare)
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Microwave convective drying of plant foods at constant and variable microwave power
- 2007
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 25:42193, s. 1149-1153
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Tidskriftsartikel (refereegranskat)abstract
- Microwave convective drying of plant foods is a promising process due to the shorter drying time and better product quality. High microwave power decreases the drying time but causes charring of the product. In this work, microwave drying under constant and variable microwave power were compared. Temperature-sensitive products, such as plant foods, are especially affected by microwave power during the final drying period. Therefore, drying at variable microwave power was found to be a more suitable drying process. Air (temperature and velocity) has an important role during microwave drying, not only as carrier of evaporated moisture but also as it contributes to a more homogeneous and faster drying.
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2. |
- Ananías, Rubén A., et al.
(författare)
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Collapse of Eucalyptus nitens Wood after Drying Depending on the Radial Location Within the Stem
- 2014
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 32:14, s. 1699-1705
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Tidskriftsartikel (refereegranskat)abstract
- Collapse is almost certain to occur in the industrial drying of Eucalyptus nitens, and as such this prevents the lumber manufacturing industry in Chile from producing commercial solid wood products from this species. This problem is still unsolved, and different studies to reduce collapse are currently underway. In this exploratory study, shrinkage and collapse after drying of Eucalyptus nitens was measured for boards cut from different radial locations within the stem (core, transition and outer wood from pith to bark) and having different annual ring orientation (flat-sawn and quarter-sawn). Even though exploratory, the results appear to confirm that pieces that were cut from the center of the trees were less susceptible to collapse than the pieces cut from the transition zone between the center and the periphery. On average, collapse in transition wood was approximately 50% higher than the collapse observed in wood cut from the central zone of the trees.
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3. |
- Ananías, Rubén A., et al.
(författare)
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Drying Schedules for Canelo Wood
- 2013
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 31:3, s. 282-285
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Tidskriftsartikel (refereegranskat)abstract
- Canelo wood is a highly valued native species in Chile that shows delicate marbling patterns with a pinkish soft silver luster. Due to its decorative qualities, canelo wood is dried for the manufacture of furniture and musical instruments. However, canelo wood lacks vessels cells that typically transport the water in hardwoods. Per its drying behavior, canelo wood is considered a transition species between hardwoods and softwoods. Therefore, this article reports drying schedules that were developed for drying 25-mm and 50-mm canelo lumber. In addition, this article reports experimental overall mass transfer coefficients, so that drying times for each of the drying stages can be easily estimated
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4. |
- Ananías, Rubén A., et al.
(författare)
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Energy Consumption in Industrial Drying of Radiata Pine
- 2012
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 30:7, s. 774-779
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Tidskriftsartikel (refereegranskat)abstract
- This article reports the results of an exploratory study designed to reduce heat and electricity consumption in industrial drying of radiata pine. The experiments were performed with slight modifications of the standard drying schedules used by the sawmill to dry radiata pine in 100-m 3 industrial kilns. The heat and electricity consumption were determined with data collected during the drying runs and calculations based on mathematical models. The results showed that depending on the case, heat and power consumption were respectively reduced by up to 14 and 35%.
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5. |
- Ananías, Rubén A., et al.
(författare)
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Testing New In-Kiln Meter for Monitoring Lumber Moisture Content during Drying
- 2013
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 31:3, s. 277-281
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to test a new in-kiln sensor for monitoring lumber moisture content during industrial drying. The theoretical foundation of the technology was already known, because it is based on electrical conductivity, but the mechanism of implementation was new and required validation. For this reason, the technology was compared with two other widely used methods for assessing lumber moisture content, namely, the oven-drying and electrical capacitance methods. The tests were performed in a 120-m3 industrial kiln operated by a sawmill in the eighth region of Chile, and the results showed that the average moisture content at the end of drying was satisfactorily determined by the new in-line sensor. As predicted by theory, the sensor was not able to accurately measure moisture content above 25%, but it was still able to provide the equivalent of a drying curve for monitoring of the drying process
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6. |
- Anderberg, Anders, et al.
(författare)
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Drying and hydration of cement based self-leveling flooring compounds
- 2007
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Ingår i: Drying Technology. - : Informa UK Limited. - 1532-2300 .- 0737-3937. ; vol 25:no 12, s. 1995-2003
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Tidskriftsartikel (refereegranskat)abstract
- Water in building materials not only influences important physical properties and chemical processes but is also related to the well-being of the occupants of a building. The drying of cementitious materials is complex, involving several different drying processes. The conditions for each drying process change as the material changes its properties as it goes from a particle suspension in the fresh state to a fine porous material in the hardened state. The present article describes and quantifies the drying processes of cement-based self-leveling flooring compounds (SLCs) and relates them to the extent of reaction, which here is quantified by isothermal calorimetry. The relative importance of the different drying processes is discussed and a model for the drying of the SLCs is proposed.
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7. |
- Antti, Lena, et al.
(författare)
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Investigation of the heating of wood in an industrial microwave applicator : theory and practice
- 2000
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Ingår i: Drying Technology. - : Informa UK Limited. - 0737-3937 .- 1532-2300. ; 18:8, s. 1665-1676
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Tidskriftsartikel (refereegranskat)abstract
- In this work a comprehensive set of experimental results are used as an excellent means to understand the coupling that exists between the material and the electromagnetic fields in a specific industrial microwave applicator. The analysis of the infrared images allows an accurate map of the power and temperature distributions within the wood sample to be determined. This map, together with the simulation results of a previously developed computational electromagnetic model, can provide a detailed understanding of the design features of the microwave applicator. In particular, it is possible to locate the occurrence of localised hot spots and to examine the uniformity of the heat distribution throughout the sample. The simulation results provide the evolution of the electromagnetic fields inside the entire applicator and the sample. The coupling of theory and practice is the best way to proceed in optimising the design and for proposing new applicator geometry that can heat the material more effectively.
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8. |
- Bengtsson, Peter, 1974-
(författare)
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Experimental Analysis of Low-Temperature Bed Drying of Wooden Biomass Particles
- 2008
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Ingår i: Drying Technology. - : Taylor & Francis. - 0737-3937 .- 1532-2300. ; 26:5, s. 602-610
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Tidskriftsartikel (refereegranskat)abstract
- This report investigates the low-temperature bed drying of biomass particles for use in a gasification process. Experimental drying equipment capable of drying up to 0.25 m 3 of biomass batchwise was constructed. The experimental result indicates that the drying equipment and applied method are appropriate to evaluate different drying parameters and their influence on the drying course. Drying parameters such as air temperature, air velocity, bed height, and type of wood are studied regarding the drying rate, final moisture content in the material, and bed pressure drop. The constant-rate and falling-rate drying period are studied to obtain an energy efficient drying process. Measurements show that the drying zone (where the actual drying occurs) progresses irregularly through the bed.
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9. |
- Bengtsson, Peder, et al.
(författare)
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Performance Study of a Closed-Type Heat Pump Tumble Dryer Using A Simulation Model and an Experimental Set-Up
- 2014
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Ingår i: Drying Technology. - : Taylor & Francis Group. - 0737-3937 .- 1532-2300. ; 32:8, s. 891-901
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Tidskriftsartikel (refereegranskat)abstract
- In the interests of competitiveness, manufactures of tumble dryers are seeking to reduce both their electricity use and the drying time. This study examines how the cylinder volume of the compressor and the total heat transfer of the condenser influence the drying time and electricity use in a heat pump tumble dryer. A transient simulation model was developed and compared to an experimental set-up with good similarity. The simulations show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity.
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10. |
- Berg, C G A, et al.
(författare)
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Transport equations for moist air at elevated wet bulb temperatures
- 2004
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Ingår i: Drying Technology. - 1532-2300. ; 22:1-2, s. 201-224
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Tidskriftsartikel (refereegranskat)abstract
- In meteorological applications psychrometers are used both as a humidity transfer standard and as a measurement instrument. Unfortunately wet bulb temperature, t(wb), is not a thermodynamic property and consequently, in equation linking vapor pressure and temperature, the psychrometer constant, from now on called the psychrometer coefficient, a, must be experimentally evaluated. Both theoretical formulations and experimental results show that the psychrometer coefficient, a, depends on a number of parameters. In this work a thermodynamic model of the coupled heat and mass transfer formulation of an adiabatic drying process is derived to state the adiabatic saturation temperature, t(as). Derived equations are also used in a couple of calculated examples to show to the reader why some psychrometric relations tend to be less usable at high wet bulb temperatures. The authors have found, based on the calculations, that the past conclusions of experimental studies of adiabatic evaporation from a water surface in humid air may verify both an assumption that the apparent heat transfer coefficient, is greater than the apparent mass transfer coefficient, alpha'(tot), (i.e., alpha(tot) > alpha'(tot) and t(wb) > t(as)) as well as an assumption that the apparent heat transfer coefficient is smaller than the apparent mass transfer coefficient (i.e., alpha(tot) < alpha'(tot) and t(wb) < t(as)) although pure analogy considerations propose that the apparent heat transfer coefficient is smaller than the apparent mass transfer coefficient (i.e., alpha(tot) < alpha'(tot) and t(wb) < t(as)).
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