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

Wood Research ◽  
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.

scholarly journals Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

2021 ◽  
Vol 30 (1) ◽  
pp. e002
Author(s):  
Juan I. Fernández-Golfín ◽  
Maria Conde Garcia ◽  
Marta Conde Garcia
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Solid Wood ◽  
Wood Products ◽  
Wood Moisture Content ◽  
Accurate Estimation ◽  
Wood Moisture ◽  
Mathematical Functions ◽  
Measured Moisture Content

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and  maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

scholarly journals Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1672
Author(s):  
Hannes Stolze ◽  
Mathias Schuh ◽  
Sebastian Kegel ◽  
Connor Fürkötter-Ziegenbein ◽  
Christian Brischke ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Wood Moisture Content ◽  
Adhesive Systems ◽  
Wood Moisture ◽  
Near Surface ◽  
Finger Joints ◽  
Glued Laminated Timber ◽  
Delamination Resistance ◽  
Normative Requirements

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

Flake Drying Temperature Affects Mat Properties during Pressing

Holzforschung ◽  
2002 ◽  
Vol 56 (5) ◽  
pp. 558-562 ◽  
Author(s):  
C. J. Martino ◽  
S. Shrauti ◽  
S. Banerjee ◽  
L. P. Otwell ◽  
E. W. Price
Keyword(s):  
Contact Angle ◽  
High Temperature ◽  
Surface Hydrophobicity ◽  
Environmental Benefits ◽  
General Shape ◽  
Drying Temperature ◽  
The Core ◽  
Pore Closure ◽  
Lower Temperature ◽  
High Temperature Drying

Summary The contact angle of water on wood rises sharply as the wood approaches dryness. The general shape of the rise can be reproduced through thermodynamic calculations that consider the presence of extractives on the surface. SEM work confirms that extractives move progressively to the surface with increasing drying temperature. Other factors such as pore closure also contribute to surface hydrophobicity. The temperature profile within a stack of flakes during accelerated pressing shows a break at 100°C when flakes dried at high temperature are processed. Moisture is known to be driven from the outer layers of the stack to the core during early pressing. If the flake surface is hydrophobic then this moisture would film on the surface rather than penetrate into the flake. Subsequent evaporation of the moisture would lead to high pressure. Hence, flakes dried at high temperature should be more prone to delamination. High-temperature drying also promotes VOC emissions and there should be operational and environmental benefits to drying at lower temperature.

Observations on the biology of Lycts Brunneus (Steph.)

1953 ◽  
Vol 1 (1) ◽  
pp. 102 ◽  
Author(s):  
FJ Gay
Keyword(s):  
Heat Treatment ◽  
Life Cycle ◽  
Relative Humidity ◽  
Sex Ratio ◽  
Moisture Content ◽  
Incubation Period ◽  
Developmental Period ◽  
Wood Moisture Content ◽  
Optimal Conditions ◽  
Wood Moisture

An account is given of certain aspects of the biology of Lyctus brunneus (Steph.). Female beetles are able to oviposit within 24 hr. after emerging from infested timber and deposit an average of more than 70 eggs per female over a period of 1-2 weeks. Eggs are deposited at depths of 1.0-6.5 mm. in the wood vessels, preferentially from a transverse surface, but also through radial and tangential faces. The incubation period of the eggs ranges from about 1 week at 26�C, to 3 weeks at 15�C. The egg-adult developmental period ranges from 4 months at 26�C. to 16 months or more at 15�C. Under optimal conditions of temperature, relative humidity (and hence wood moisture content), and nutrition, the life cycle may be as short as 2 months. The sex ratio of L. brunneus is 1 : 1 and the adult beetles live from 2.5 to 7 weeks, depending upon the temperature, females being somewhat longer-lived than males. The larvae of L. brunneus are somewhat more resistant to heat treatment than are the eggs, but one 1/2hr. exposure to 50�C. is completely lethal to both stages.

scholarly journals Kajian Pengering Kopi Gayo Semi Basah Menggunakan Alat Pengering Tipe Hohenheim

2020 ◽  
Vol 4 (4) ◽  
pp. 362-371
Author(s):  
Antoni Hardi ◽  
Ichwana Ichwana ◽  
Rita Khathir
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Water Content ◽  
Drying Process ◽  
Arabica Coffee ◽  
Drying Temperature ◽  
Average Daily Temperature ◽  
Coffee Beans ◽  
Simple Technology

Abstrak. Sebagai produsen kopi Arabica, masyarakat Gayo terkendala pada suhu lokal di Aceh Tengah yang relatif dingin dan teknologi sederhana yang digunakan untuk proses pengeringan kopi. Suhu rata-rata harian adalah 23-29°C. Bahan yang digunakan pada penelitian ini yaitu biji kopi yang diolah dengan metode semi basah sebanyak 9kg. Parameter penelitian meliputi suhu pengeringan, kelembaban relatif, kadar air dan rendemen. Hasil penelitian menunjukkan bahwa suhu pengeringan menggunakan alat pengering Hohenheim jauh lebih tinggi sekitar 10-20°C dari suhu pengeringan secara penjemuran. Proses pengeringan kopi labu sampai bisa digiling membutuhkan waktu selama 12 jam yaitu 8 jam pada hari pertama dan 4 jam pada hari ke-2. Sedangkan proses pengeringan tahap 2 membutuhkan waktu selama 16 jam sampai menghasilkan kopi beras dengan kadar air 9,32%. Kualitas kopi beras yang dihasilkan sudah baik dengan kadar air  yang sudah memenuhi standar SNI, tidak berbau busuk, dan tidak terkontaminasi. Nilai rendemen kopi beras berbasis kopi labu adalah 35%.Study of Drying Semi Washed Gayo Coffee Use Dryer Type Hohenheim Abstrack. As an Arabica coffee producer, the Gayo community is constrained by the relatively cold local temperatures in Central Aceh and the simple technology used for the coffee drying process. The average daily temperature is 23-29 ° C. The material used in this study was coffee beans which were processed by the semi-wet method of 9kg. Research parameters include drying temperature, relative humidity, moisture content and yield. The results showed that the drying temperature using a Hohenheim dryer is much higher around 10-20 ° C than the drying temperature by drying. The process of drying pumpkin coffee until it can be ground needs 12 hours, which is 8 hours on the first day and 4 hours on the second day. While the process of drying stage 2 takes 16 hours to produce rice coffee with a moisture content of 9.32%. The quality of rice coffee produced is good with water content that meets SNI standards, does not smell bad, and is not contaminated. The yield of pumpkin coffee-based rice coffee is 35%.

scholarly journals Kajian Pengeringan Bak Gabah Secara Intermittent Terhadap Mutu Beras

2020 ◽  
Vol 7 (3) ◽  
pp. 171-178
Author(s):  
Achmad Fitrah Maulidin ◽  
Leopold Oscar Nelwan ◽  
Rokhani Hasbullah
Keyword(s):  
High Temperature ◽  
Moisture Content ◽  
Research Method ◽  
Drying Method ◽  
Drying Process ◽  
Drying Temperature ◽  
Head Rice ◽  
Grain Drying ◽  
Drying Treatment ◽  
High Head

Grain drying with bed dryer is generally effective with high temperatures, but this can increase fissured rice percentage. This can be overcome by combining drying method with tempering. These study were aim to examine drying temperature and duration on bed dryer using intermittent high temperature dryer, and its effect on quality variety of Ciherang with 20-22% moisture content. These research method consists of drying treatment without tempering using 35°C, 60°C and 80°C temperatures to 14% moisture content. Drying treatment with tempering consists of initial drying process-initial tempering-second drying- second tempering or without tempering, where the first drying temperature were 80°C for 20 minutes, 60°C for 30 minutes and second drying temperature were 60 °C and 35°C to 14% moisture content. The tempering duration used was 90 minutes. Results showed the grain drying method without tempering 35°C gave the highest percentage of head rice. However, the use of tempering had significantly reduced cracking and increased head rice percentage compared without tempering at the same temperature. Initial drying of 60°C for 30 minutes-tempering for 90 minutes-drying both temperatures of 35°C to 14% moisture content had been able to produce high head rice and low fissured rice percentage respectively 81.41% and 10%.

scholarly journals Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

2021 ◽  
Vol 30 (1) ◽  
pp. e002
Author(s):  
Juan I. Fernández-Golfín ◽  
Maria Conde Garcia ◽  
Marta Conde Garcia
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Solid Wood ◽  
Wood Products ◽  
Wood Moisture Content ◽  
Accurate Estimation ◽  
Wood Moisture ◽  
Mathematical Functions ◽  
Measured Moisture Content

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and  maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

Use of Modified Lactobacillus Selective Medium and Bifidobacterium Iodoacetate Medium for Differential Enumeration of Lactobacillus acidophilus and Bifidobacterium spp. in Powdered Nutritional Products

1999 ◽  
Vol 62 (1) ◽  
pp. 77-80 ◽  
Author(s):  
STEVEN C. INGHAM
Keyword(s):  
Acetic Acid ◽  
High Temperature ◽  
Relative Humidity ◽  
Lactobacillus Acidophilus ◽  
Iodoacetic Acid ◽  
Selective Medium ◽  
High Relative Humidity ◽  
Bifidobacterium Lactis ◽  
Highly Correlated ◽  
De Man

Modified Lactobacillus selective agar (APT agar + sodium acetate and glacial acetic acid; mLBS) was compared to selective modified Lactobacillus selective medium (LBS agar + tomato juice and acetic acid; mLSM) and nonselective de Man Rogosa Sharpe (MRS) agar for the enumeration of Lactobacillus acidophilus in probiotic-containing powdered nutritional products. The mLBS agar was equivalent to MRS agar and superior to the mLSM agar for enumerating L. acidophilus in products stored in sealed cans at 22°C. When samples were analyzed for L. acidophilus concentration after high temperature storage in sealed cans or storage in open cans at high relative humidity, the mLBS and MRS agars were highly correlated (r2 = 0.93). Modified Bifidobacterium iodoacetate medium (12.5 mg iodoacetic acid/liter; mBIM) was compared to MRS agar + bile, cysteine, and dicloxacillin (MRS + BCD) for enumerating Bifidobacterium infantis or Bifidobacterium lactis in the nutritional products. The two media were equivalent for enumerating B. infantis in product stored at 22°C in sealed cans. However, the two media were poorly correlated (r2 < 0.50) for enumeration of B. infantis and B. lactis in products stored in sealed cans at high temperature or in open cans at high relative humidity. The mLBS medium has potential industry application as a relatively inexpensive, convenient differential enumeration method for L. acidophilus. The mBIM medium cannot be recommended as a sole medium for enumeration of probiotic Bifidobacterium spp. in powdered nutritional products stored under high temperature and/or high relative humidity conditions.

Sign in / Sign up

Export Citation Format

Share Document