Increases in the longevity of desiccation-phase developing rice seeds: response to high-temperature drying depends on harvest moisture content

AbstractDrying reduces seed moisture content, which improves subsequent seed survival periods. Diverse maximum temperatures have been recommended to limit or avoid damage to seeds, but some high-temperature drying regimes may improve subsequent seed quality. Seeds from 20 different accessions of five rice (Oryza sativaL.) variety groups (aromatic, Aus, Indica, temperate Japonica, tropical Japonica) were harvested over several seasons at different stages of maturation and either dried throughout at 15°C/15% relative humidity (RH) or for different initial periods (continuous or intermittent) in different drying regimes at 45°C before final equilibrium drying at 15°C/15% RH. Subsequent seed longevity in hermetic storage at 45°C with 10.9% moisture content was determined. In no case did initial drying at 45°C provide poorer longevity than drying at 15°C/15% RH throughout. There was a split-line relation, which did not differ amongst investigations, between longevity after initial drying at 45°C relative to that at 15°C/15% RH throughout and harvest moisture content, with a break point at 16.5% (a seed moisture status of about –14 MPa). Below 16.5%, relative longevity did not differ with harvest moisture content with little or no advantage to longevity from drying at 45°C. Above 16.5%, relative longevity showed a positive relation with harvest moisture content, with substantial benefit from drying at 45°C to subsequent longevity of seeds harvested whilst still moist. Hence, there are temporal (immediatelyex plantacf. subsequent air-dried storage) and water status discontinuities (above cf. below 16.5%) in the effect of temperature on subsequent air-dried seed longevity.

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STUDY ON CONCENTRATIONS OF ACIDS AND ALCOHOLS EMITTED BY PINUS RADIATA DURING HIGH-TEMPERATURE DRYING

Wood Research ◽

10.37763/wr.1336-4561/66.3.427436 ◽

2021 ◽

Vol 66 (3) ◽

pp. 427-436

Author(s):

Jiangyi Chu ◽

Jinghui Jiang ◽

Chusheng Qi ◽

Yongdong Zhou

Keyword(s):

Acetic Acid ◽

High Temperature ◽

Relative Humidity ◽

Moisture Content ◽

Formic Acid ◽

Pinus Radiata ◽

Wood Moisture ◽

Drying Temperature ◽

Kiln Temperature ◽

High Temperature Drying

The purpose of this paper is to investigate the influence of kiln temperature, relative humidity and wood moisture content on the content of acid and alcohol released in the drying process of high temperature kiln by studying the radiated pine sawn timber of 40mm thickness. The drying temperature was between 101°C and 115°C, the relative humidity in the drying kiln was reduced from 86.1% to 39.6%, the moisture content of the lumber was reduced from 106.16% to 11.98%, and gas extraction was executed nine times with an extraction speed of 1.0 L•min-1 and a sampling time of 30 min. The concentrations of acids and alcohols were analyzed by HPLC. The results showed that the concentrations of formic acid, acetic acid, and methanol emitted in the kiln during drying were 215.6-748.2, 4148.8-16803.2, and 6381.9-15648.9 mg•m-3, respectively, and these concentrations were significantly higher than the relevant standards. The concentrations of the emitted formic acid and acetic acid were proportional to the drying temperature, the concentrations of the emitted formic acid and acetic acid were inversely proportional to the relative humidity in the kiln and the moisture content of the lumber. The concentration of the emitted methanol was independent of the drying temperature, relative humidity in the kiln, and moisture content of the lumber. It is therefore suggested that formic acid, acetic acid, and methanol be separately recovered during the high-temperature drying of Pinus radiata lumber.

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Simulation of Temperature and Moisture Content Profiles in aPinus radiataBoard during High-Temperature Drying

Drying Technology ◽

10.1080/07373930701226922 ◽

2007 ◽

Vol 25 (4) ◽

pp. 547-555 ◽

Cited By ~ 10

Author(s):

M. N. Haque

Keyword(s):

High Temperature ◽

Moisture Content ◽

High Temperature Drying

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Industrial Kiln Drying and its Effect on Microstructure, Impregnation and Properties of Scots Pine Timber Impregnated for Above Ground Use. Part 1. Effects of Initial, Final Dryings and Preservative on Impregnation and Timber Quality

Holzforschung ◽

10.1515/hf.2002.066 ◽

2002 ◽

Vol 56 (4) ◽

pp. 428-433 ◽

Cited By ~ 7

Author(s):

N. Terziev

Keyword(s):

High Temperature ◽

Moisture Content ◽

Scots Pine ◽

Mixed Model ◽

Strong Relationship ◽

Final Moisture Content ◽

Sapwood Area ◽

Timber Quality ◽

Kiln Drying ◽

High Temperature Drying

Summary Scots pine (Pinus sylvestris L.) planks were dried in industrial progressive, conventional batch and high temperature kilns. The quality of drying was assessed by measuring the final moisture content and its gradient, deformations, checks and internal stress of planks. The timber was rearranged in three charges and impregnated in an industrial autoclave with copper-based preservatives for above ground use (class AB):Kemwood ACQ 1900, Tanalith E and Wolmanit CX-8. The moisture content was determined after impregnation and the planks were divided into two charges; the first was dried in an industrial conventional batch kiln while the second was air dried. Assessment of the final product quality after kiln and air drying was carried out as after the initial drying. The penetration of preservatives was measured as well. The data were analysed by a statistical mixed model to ascertain the effects of drying and preservatives on the impregnation and timber quality. A strong relationship was found between the initial drying of Scots pine timber and its quality after impregnation and drying. The conventional batch and high temperature kiln drying ensured similar drying quality regarding the final moisture content and gradient, bow, twist and checks, but the high temperature drying provided significantly better (94.4%of the total sapwood area) penetration of the preservatives tested. It is suggested that changes in wood structure could be provoked during the high temperature drying, thus improving the subsequent impregnation and secondary drying. The progressive and conventional batch kiln drying led to similar penetration of the preservatives; the conventional batch kiln drying ensured significantly lower final moisture content, less twist and surface checks of the timber than the progressive kiln drying. Wolmanit CX-8 penetrated significantly better into the pine sapwood (96.3%) than Kemwood ACQ 1900 and Tanalith E (83.5 and 88.5%, respectively). The planks impregnated with Wolmanit CX-8 achieved the best quality regarding the final moisture content, its gradient and cup. The planks impregnated with Kemwood ACQ 1900 and Tanalith E showed similar quality regarding the penetration and some deformations after drying, but Kemwood ACQ 1900 impregnated planks had highest moisture content and gradient.

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Determining the speed and acceleration of the separator for grass leaf part in horizontal and vertical directions

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2021.242957 ◽

2021 ◽

Vol 5 (1(113)) ◽

pp. 41-50

Author(s):

Tokhtar Abilzhanuly ◽

Seitkazy Keshuov ◽

Askar Rzaliyev ◽

Omirserik Zhortuylov ◽

Gani Zhumatay ◽

...

Keyword(s):

High Temperature ◽

Moisture Content ◽

Operating Costs ◽

Theoretical Research ◽

Carotene Content ◽

Air Heating ◽

Side Walls ◽

Main Component ◽

Leaf Part ◽

High Temperature Drying

Vitamin-grass flour is the main component of mixed fodders intended for all types of livestock and poultry. Earlier and currently, the vitamin-grass flour has been prepared from legumes by a high-temperature drying technique. However, existing techniques have high operating costs and require very expensive technical tools. To reduce the specific operating costs and the price of equipment in the production of VGF, a technique has been proposed that involves the main drying of grass to a moisture content of 30‒35 % on a swath while the post-drying of grass is performed in a small-sized channel under the haystack without air heating. Next, the dried mass is pre-crushed. At the same time, the delicate leaf part of the hay, while falling between the side walls of hammers and counter-hammers, is ground and finely crushed, and the stems are processed into large fractions. From pre-crushed hay, the leaf part is separated and fed into the crusher to produce flour. In this case, the main machine that determines the performance of the line is the separator of the leaf part of the grass. The results of the theoretical research have established the speed and acceleration of hay movement on the surface of the sieve. These values determine the productivity of separation of the leaf part from pre-crushed hay and the reliability of the selected structural and technological scheme of the separator. The production tests have confirmed the reliability and economic efficiency of the proposed technique. Comparing the proposed technique for obtaining vitamin-grass flour by existing high-temperature methods has shown that the carotene content in flour was 1.6 times higher while the specific operating costs and equipment price were 6‒7 times lower

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