Uneven Drying Research Articles

Optimierung der Luftführung eines Bandtrockners mittels Strömungssimulation

Uneven drying often occurs in belt dryers which leads to an increase in energy consumption and a decreased throughput. To optimise the system a fluid flow simulation was performed aided by computational fl uid dynamics (CFD), supported by actual measurements. The installation of guiding plates and the optimised adjustment of the flaps inside the air supply duct can provide an effective approach for a better air supply.

Non-lethal freezing effects on seed degreening in Brassica napus

The effects of a non-lethal freezing stress on chlorophyll content, moisture level and distribution, and abscisic acid (ABA) levels were examined in siliques and seeds of Brassica napus (canola). A non-lethal freezing stress resulted in the retention of chlorophyll in seed at harvest that was most pronounced for seeds 28, 32 and 36 days after flowering (DAF). This increase was primarily due to an increased retention of chlorophyll a relative to chlorophyll b. Chlorophyll retention in seeds exposed to a non-lethal freezing stress correlated with an increased ABA catabolism, as measured 1, 3 or 7 days after the stress treatment. Although the non-lethal freezing stress had no significant effect on moisture content in seeds of siliques stressed at 28-44 DAF, moisture distribution, as viewed by magnetic resonance imaging, showed an uneven drying of 32 and 40 DAF siliques after exposure to the non-lethal freezing stress. Moisture was initially lost more rapidly from the silique wall between seeds, than in control non-stressed siliques. Increased moisture loss was not due to structural changes in the vasculature of the silique/seed of stressed tissues. These results are consistent with the hypothesis that a non-lethal freezing stress-induced decrease in ABA level, during seed maturation, effects an inhibition of normal chlorophyll a catabolism resulting in mature but green B. napus seed.

How to … Level Temperature Profiles for Mat Line Dryers

In addition to achieving a consistent mat formation and binder application, it is the uniformity of subsequent drying and curing that is critical to the production of high-quality thermoset nonwoven mats. Uneven drying and/or curing, especially in the cross-machine direction will result in over/under drying/curing, edge curls, web breaks and high trim and/or scrap factors. This paper reviews several design and set-up techniques that have resulted in cross-machine temperature profiles as low as +/- 1°F on a web 16 feet wide. The recent start-up of a line producing fiberglass mat (roofing shingle substrate) serves to illustrate how the control of air mixing, distribution, and flow through the product can be combined to produce a level web temperature profile. While the results pertain to a new production line, the techniques for reducing web temperature profiles may also be applied to existing dryer equipment

Spherical-shape Y2SiO5:Ce Phosphor Prepared from Organic Precursor Solution by Spray Pyrolysis

Ce-doped SiO phosphor particles of spherical morphology, fine size, high crystallinity and high photoluminescence (PL) intensity were prepared by spray pyrolysis. When nitrate precursor solution is adopted, hollow particles were formed by uneven drying rate between surface and inside of droplet. Citric acid and ethylene glycol were introduced as polymeric precursor to control the morphology of particles. When polymeric solution is adopted, polymeric chain is formed by the esterification reaction between carboxyl and hydroxy groups of citric acid and ethylene glycol, and considered as controlling the drying characteristics of droplet. :Ce phosphor particles prepared from polymeric precursor solution were spherical, filled, fine size and not agglomerate before and after post heat treatment. The optimum doping concentration of cerium was 0.5 mol% of overall solution concentration. The optimum amount of TBOS of high PL intensity and pure crystallinity of X2-type was 105% of stoichiometric amount. The PL intensity of X :Ce phosphor particles prepared using the polymeric precursor solution was 164% of that of the nitrate precursor solution due to homogeneous composition and good morphology.y.

The effect of ADD-H preservative (ammonium propionate) on the quality and feedingvalue of baled hay

The effect of ADD-H at 3 or 4 rates of application on the quality and feeding value of baled hay at 3 dey matter levels (65.0—69.9, 70.0—74.9 and 75.0—79.9 %) was studied on Hankkija’s farm in Kangasala and at DM 78—82 % on the Koivisto farm in Hausjärvi. The field experiments were performed in 1979 and the testing of the hay completed by the following spring. The field experiments were affected by uneven drying of the hay, uneven rewetting due to rainfall after cutting, loss of ADD-H during application, uneven distribution of ADD-H in the bales, and other factors. At DM 65.0—69.9 % ADD-H gave only a slight improvement in hay quality; at the highest application rate the sugar content was the highest and the crude fibre content the lowest. At the other DM levels ADD-H restricted the generation of heat during storage; the sugar content was higher, and the mould count lower, in the treated hay than in the untreated hay. The beneficial effect of ADD-H on the feeding value of baled hay was small; further study on this aspect is required.

'Modular Serendipity': A Vacuum-Formed Modular Plastic Mural

The mural illustrated in Fig. 1, entitled 'Modular Serendipity', was installed in 1977 in the Main Place of the University of Wisconsin-Parkside at Kenosha, Wisconsin, U.S.A. It measures 7.5 x 3.3 m, consists of 21 modular units, each 91 x 91 cm, and it is mounted 45 cm from the wall. It is lit from above by daylight from a 30?angled glass roof. The work had its genesis in the industrial use of vacuum-forming techniques for objects made of plastics. I began, in 1968, to use a vacuum-former in Birmingham, England, at the Birmingham Polytechnic. There it was used mainly by students of industrial design for making items such as picnic trays and advertising signs. I was interested in the technique because it makes it possible to produce copies of 3-dimensional artworks of the multiple type as quickly and as easily as producing, say, lithograph prints. The viewing of a group of vacuum-formed 3dimensional tile-like artworks seemed to me to be of much more artistic interest than viewing one alone. If a unit does not have a symmetrical design, then a number of the units can be grouped in different combinations of the orientation of the unit to provide a variety of relief configurations. For a discussion of this type of artwork see Ref. 1. In 1969, an exhibition took place at the Institute of Contemporary Arts in London called 'Cybernetic Serendipity' [2]. Some of the exhibition was devoted to artworks by artists who had chosen to incorporate chance effects as an integral aspect of their visual character. At that time, I was a lecturer at the Birmingham Polytechnic School of Art Education and carried out some projects with students using sets of parameters for artworks that included chance effects [3]. The original model of the unit for the mural was made in clay over a wooden armature. Its large dimensions (91 x 91 cm) posed some difficulties, since variations in the depth of the clay skin tended to cause uneven drying. From this model a 5 cm-thick plaster cast was made. This was reinforced in parts with scrim and with light steel rods. This cast was, of course, a negative of the final mural unit. It is sometimes possible to vacuum-form directly into such a female mold if heat-resistant plaster is used, but it seemed wiser, because of the size and the 21 units required, to make a positive cast from the plaster in fiberglass-reinforced resin. The cast was between 10 and 13 mm thick. Since between 1.8 and 2.0 kg/sq cm (25 and 28 lb/sq in.) pressure is applied in the forming process, a

Selection of Sources of Infrared Radiation for Drying Processed Motion-Picture Films

Forced methods of drying processed motion-picture films take advantage of the principles of convective heat transfer and radiative heat transfer. Although in principle an infrared radiation source is good for this purpose because it can concentrate heat below the surface of the film, in the past there have been difficulties because different film densities absorb radiation differently, which leads to uneven drying and distortion of the film. An optimum infrared source would have a radiation spectrum corresponding closely with the film's absorption spectrum and during drying would maintain an equilibrium of moisture content between the emulsion and the base. Source-emittance and film-absorption characteristics were examined with an IKS-14 infrared spectrophotometer operating in the double-beam mode from 0.75 to 15 μm, A wavelength band was found in which variation in image density has little effect on the absorption of infrared radiation. A tubular metal emitter at a temperature of about 480 K (about 405 °F) is found to be nearly optimum.

抄紙機ドライパートの湿紙乾燥に関する理論的解析の問題点に対する若干の考察と高速抄紙機における湿紙乾燥の実際的な考察 ＩＩ

There exist very few reports or studies for the purpose of improving quality of final products, efficiency and operation by measuring and analyzing tendency of paper drying on dryer part actually operated wide and high speed paper machine. This is mainly because the higher the paper machine speed, the measurement of dryer part increase the possibility of production loss and is also more hazardous from safety stand point. I have measured moisture content distribution in each pocket of dry part and dryer surface temperature under special countermeasures against above mentioned difficulties and have investigated influences of so-called “chimney” and “ventury” effect together with relation to the uneven drying of products, of which results are presented in this paper. I have found unexpectedly high non uniform moisture and temperature profile in case of canvas air system dryer. The fact that cross machine moisture profile in the pockets of wet and dryers is not uniform, easily causes uneven drying which is impossible to be corrected by the subsequent dryers. Dryer surface temperature is high on back side because drying steam has too much superheat. “Chimney” and “ventury” effects have no negligible influence and I have been able to confirm many facts which hitherto were only conjectures. This measurement was executed on a paper machine of 6, 960 mm wire width and 650 m/min. operating speed. The measuring method was as shown in fig. 9.

Glycol for controlling evaporation in mounting of frozen brain sections.

Mounting individual frozen sections which are wrinkle free requires manipulations which expose them to fragmentation. Large and fragile sections are especially vulnerable. We wish to report a method which minimizes handling and damage to these sections during mounting. The techniques described by Heringa and ten Berge (1923), Iwanoff (1936), Albrecht (1954) and Case (1969) have been used successfully for many years but require blotting or transfer to ethanol solutions and as a result sections may be lost or damaged and wrinkles which develop may be difficult to avoid during rapid or at times uneven drying.

British Food Journal Volume 45 Issue 1 1943

British Food Journal Volume 45 Issue 1 1943

British Food Journal Volume 44 Issue 12 1942

British Food Journal Volume 44 Issue 12 1942