Air-dried Moisture Content Research Articles

Effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork grown in Korea

The effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork (Qv VC) were examined and compared with those of Quercus suber reproduction cork (Qs RC). The water treatment was conducted at 100 °C for 1 h. Qv VC showed a significantly higher dimensional change in the three directions and lower weight loss than Qs RC by boiling water treatment. Untreated and boiled Qv VC showed higher density, air-dried moisture content, red/green (a*) and yellow/blue (b*) chromaticity, overall color change, shrinkage in all three directions, moisture adsorption on the entire surface, and swelling per 1% moisture content than untreated and boiled Qs RC. However, the lightness (L*) and water absorption on each surface were higher for Qs RC than for Qv VC. Moisture adsorption on each surface was comparable before and after heat treatment for both species. After boiling water treatment, the air-dried moisture content, dimensions, volume shrinkage, water absorption, and moisture adsorption on each surface and the entire surface increased, whereas L*, a*, b*, and swelling per 1% moisture content decreased. The results of the present study could be useful for further utilization of Qv cork growing in Korea.

SIFAT FISIS BAMBU SEPANJANG BATANG PADA BAMBU SERO (Schizostachyum brachycladum Kurz.)

SIFAT FISIS BAMBU SEPANJANG BATANG PADA BAMBU SERO (Schizostachyum brachycladum Kurz.)

Pengaruh Arah Aksial, Keberadaan Buku Dan Ruas Terhadap Kadar Air Dan Berat Jenis Bambu Dikawasan HKm Desa Aik Bual

Among the community, bamboo is well known for its excellent utilization, starting from its sturdy, resilient, straight stems, which are easy to split, work with, and shape. In addition, the price of bamboo is cheaper and easily found in residential areas. One of the bamboo-producing areas found in the West Nusa Tenggara region is the Aik Bual Village HKm. It is known that research related to the physical properties of bamboo has not been carried out in the area. Physical properties become a benchmark in seeing cracks and breaks in bamboo caused by high water content and low specific gravity. This study aims to review the four types of bamboo in the Aik Bual HKm area against the influence of axial direction, the presence of books and internodes, moisture content and specific gravity. Fresh water content of petung bamboo, ampel bamboo, string bamboo, galah bamboo: 90,19%; 102,72%; 122,70%; 138,95%. Air dry moisture content of petung bamboo, ampel bamboo, string bamboo, galah bamboo: 12,31%; 13,80%; 12,27%; 11,95. Fresh specific gravity of petung bamboo, ampel bamboo, string bamboo, galah bamboo: 0,63; 0,58; 0,52; 0,49. Air dry specific gravity of petung bamboo, ampel bamboo, string bamboo, galah bamboo: 0,70; 0,71; 0,57; 0,61. Furnace dry specific gravity of petung bamboo, ampel bamboo, string bamboo, galah bamboo as follows: 0,72; 0,70; 0,62; 0,59. Of the four types of bamboo used, it is known that the axial direction, the presence of books and internodes do not have a significant effect on the moisture content and specific gravity.

Karakteristik Batang dan Sifat Fisika Bambu Tali (Gigantochloa apus (Bi. Ex Schult.) Kurz) di Kawasan HKm Desa Aik Bual, Kabupaten Lombok Barat, Indonesia

Communities well know non-Timber Forest Product (NTFP) of bamboo with properties, strong culm, flexible, straight, smooth, hard, easily split and formed, very doable, and light transported easily. Besides those, bamboo is relatively inexpensive compared to other raw materials found in the village community’s vicinity. One of the bamboos found in Aik Bual Village’s community forests was tali bamboo (G. apus). Identification of G. apus was required to understand its characteristics, while the physical properties would be useful for understanding its dimension stabilities. The objectives of this study were to identify the stem characteristics and physical properties of G. apus. Experimental method was employed to conduct the study. Three culms were selected, and each culm was divided into three sections: bottom, middle, and top. Physical properties were tested using India Standard number IS 6874, 2008. The characteristics of G. apus were: the intermodal space of the bottom culm was 31.2-38.5 cm, the middle culm was 40-47 cm, and the top culm was 26-60.8 cm; the diameter of the bottom culm was 5.77-6.38 cm, the middle culm was 5.72-6.48 cm, and the top culm was 5.18-6.19 cm; the thickness of bottom culm was 0.9-1.35 cm, the middle was 0.55-0.96 cm, and the top was 0.54-0.76 cm. Physical properties of G. apus were: the fresh moisture content was 111.23%-143.24%, the air-dried moisture content was 11.78-12.72%, while the fresh density was 0.47-0.56, the air-dried density was 0.59-0.64, and the oven-dried density was 0.60-0.63.

DESKRIPSI SEBARAN JENIS DAN SIFAT FISIKA BAMBU DI KAWASAN HUTAN DENGAN TUJUAN KHUSUS (KHDTK) SENARU

Senaru specific destination forested area is the only educational forested area which is situated in Lombok Island. It has important roles in providing facilities and information supporting knowledge of bamboo characteristics growing naturally in this area. Many studies about the characteristics of bamboo have been done, but none has been conducted for this area. The information about bamboo distribution was important to understand the potency of bamboo of this area and the information about bamboo physical characteristics were used as raw material data for bamboo crafting, furniture, and simple constructions. The aims of this study were at understanding the bamboo distributions and the physical characteristics of bamboo of this area. Samplings were conducted in two phases which the first phase was collecting bamboo species, number of the bamboo clumps and sticks. The second phase was conducted several tests for the physical characteristics of the bamboo collected from the first stage. The results of this testing were described and compared to the existing bamboo quality standards. 6 (six) bamboo species were identified in this forest: yellow bamboo (Bambusa vulgaris var. striata), Petung bamboo (Dendrocalamus asper (Schult. f.) Backer ex Heyne), ampel bamboo (Bambusa vulgaris Schrad. ex J.C), Santong bamboo (Gigantochloa atter (Hassk.) Kurz), Bilis bamboo (Schizostachyum lima (Blanco) Merr) and Tali bamboo (Gigantolochloa apus Kurz). The number of bamboo clump was 160 clumps and 299 individuals. The physical characteristics of the bamboo were: fresh moisture content ranged between 37,93% – 69,49%, air-dried moisture content between 8,84% - 12,10%, fresh density ranged between 0,32 – 1,03, air-dried density ranged between 0,59 – 1,11 and oven-dried density between 0,55 – 1,04.

Analysis Of Water Requirements For Irrigation Of Green Honey Water Apple (Syzygium aqueum) In Pots

Plant irrigation water needs are important things to be met so that the plant growth is optimal starting from the vegetative phase to the generative phase. The current hot issue among potted fruit growers is the problem of dropping the ovary (pistil) on the plant. Many factors cause the fall of plant fruit, one of which is lack of water. This certainly needs special attention considering the nature of the water apple plant itself, in this study, especially the green honey water apple, it consumes quite a lot of water every day. To overcome the problem of water shortages in the green honey water apple plant, it is necessary to first know the average plant water requirement in pots through water content analysis in the laboratory at three stages of analysis and calculation of Pot Water Requirements (PWR) and Efficiency Needs Irrigation Water. Average Field Capacity Moisture Content of the potted planting media sample was 49.37%, Air Dry Moisture Content was 24.27 % and PWR 4.36 liters with an efficiency of irrigation water requirement for bulk systems (hand move or portable) of 5, 12-5.81 liters and a drip irrigation system (point source emitter) of 4.84-5.45 liters.

Near-infrared spectroscopy and hyperspectral imaging can aid in the prediction and mapping of polyploid acacia hybrid wood properties in tree improvement programs

Abstract Acacia, including Acacia hybrids, are some of the most important species grown as part of the Vietnamese wood industry. Rapid methods to identify the variations in the wood properties of Acacia hybrids however, are a currently lacking and creating limits for their breeding programs. In this study, nine Acacia hybrid clones, including those that were diploid, triploid, and tetraploid were evaluated using near-infrared spectroscopy (NIR) and hyperspectral imaging (HSI). The standard normal variate (SNV) and second derivative (SP2D) were applied to compare the performances of NIR and HSI using partial least square regression. The HSI images were acquired at wavelengths from 1033 to 2230 nm and the SNV and SP2D described the variations in the wood properties. The NIR predicted the wood physical properties better than HSI, while they provided similar predictions for the mechanical properties. The mapping results showed low densities around the pith area and high densities near the bark. They also revealed that the air-dry moisture content changed at different positions within a disk and was dependent on its position within the tree. Overall, NIR and HSI were found to be potential wood property prediction tools, suitable for use in tree improvement programs.

DESKRIPSI SEBARAN JENIS DAN SIFAT FISIKA BAMBU DI KAWASAN HUTAN DENGAN TUJUAN KHUSUS (KHDTK) SENARU

Senaru specific destination forested area is the only educational forested area which is situated in Lombok Island. It has important roles in providing facilities and information supporting knowledge of bamboo characteristics growing naturally in this area. Many studies about the characteristics of bamboo have been done, but none has been conducted for this area. The information about bamboo distribution was important to understand the potency of bamboo of this area and the information about bamboo physical characteristics were used as raw material data for bamboo crafting, furniture, and simple constructions. The aims of this study were at understanding the bamboo distributions and the physical characteristics of bamboo of this area. Samplings were conducted in two phases which the first phase was collecting bamboo species, number of the bamboo clumps and sticks. The second phase was conducted several tests for the physical characteristics of the bamboo collected from the first stage. The results of this testing were described and compared to the existing bamboo quality standards. 6 (six) bamboo species were identified in this forest: yellow bamboo (Bambusa vulgaris var. striata), Petung bamboo (Dendrocalamus asper (Schult. f.) Backer ex Heyne), ampel bamboo (Bambusa vulgaris Schrad. ex J.C), Santong bamboo (Gigantochloa atter (Hassk.) Kurz), Bilis bamboo (Schizostachyum lima (Blanco) Merr) and Tali bamboo (Gigantolochloa apus Kurz). The number of bamboo clump was 160 clumps and 299 individuals. The physical characteristics of the bamboo were: fresh moisture content ranged between 37,93% – 69,49%, air-dried moisture content between 8,84% - 12,10%, fresh density ranged between 0,32 – 1,03, air-dried density ranged between 0,59 – 1,11 and oven-dried density between 0,55 – 1,04.

Effects of One-Step Hot Oil Treatment on the Physical, Mechanical, and Surface Properties of Bamboo Scrimber.

Bamboo scrimber is a new type of bamboo-based panel that is prone to be affected by biological and service environments under outdoor conditions. In this paper, the physical and mechanical performance and the microchemical and surface properties of untreated and hot-oil-treated bamboo scrimber were analyzed to illustrate the processing mechanism of scrimber. Methyl silicone oil treatment was carried out at 120, 140, and 160 °C for 2, 4, and 6 h. The density, mechanical properties, air-dried moisture content, surface morphology, chemical structure, swelling properties, color, and contact angle of the bamboo scrimber were analyzed to evaluate the treatment effectiveness. Observation of the environmental-scanning electron microscope indicated that the glue layer of the bamboo scrimber was not significantly damaged after hot oil treatment. At low temperatures, the mechanical properties did not change significantly. Infrared-spectrum analysis showed a significant decrease in mechanical properties at higher temperatures and longer treatment time for the degradation of hemicellulose. The contact angle test and swelling properties test showed that the hot oil treatment improved the dimensional stability and reduced the wettability on the surface of the bamboo scrimber. The above analysis results show that the treatment at 140 °C for 2 h is most effective.

Uji Ketahanan Api Kayu Sengon (Paraserianthes falcataria (L.) Nielsen) yang Diawetkan dengan Bahan Pengawet Natrium Silikat (Na2SiO3)

The results of this study indicate that the average value of air dry moisture content of sengon wood is 14.081%, the air dry density is 0.326 g/m3 and oven dry density is 0.295 g/m3. The highest average retention value was at 3 days immersion with a concentration of 7% i.e. 16.161 kg/m3 and the lowest was at 1 day immersion with a concentration of 3% i.e. 5.161 kg/m3. The highest value of burn intensity at 2 days immersion with a 3% concentration i.e. 16.249% and the lowest at 1 day immersion with a concentration of 7% i.e. 6.025%. Preservation of sengon wood using natrium silicate at a concentration of 3%, 5% and 7% and immersion for 1 day, 2 days and 3 days is less effective in holding the fire rate, because the value is still below the ASTM E69 standard (2002) i.e. 7.5. The effective test of preservative (W) obtained the highest value of burn intensity at 1 day immersion with a concentration of 7% i.e. 7,490 and the lowest value at 2 days of immersion with a concentration of 3%, i.e. 3,231. The maximum temperature ranges from 206.0-291.2°C and the cooking time ranges from 206.1-607.8 seconds.

PENGARUH ARAH AKSIAL TERHADAP SIFAT FISIKA BAMBU TUTUL (Bambusa maculata) di KABUPATEN LOMBOK TIMUR

Spotted bamboo was found in West Nusa Tenggara Province, especially in Eastern Lombok Regent. This bamboo has not been studied for its physical properties so that this study was aiming at identifying the physical properties of the bamboo. The information obtained from the study might be used by people for its appropriate utilization. The axial direction was investigated with the experimental method. This method investigated correlations among treated experiments [5]. The experiment design employed was complete random design (CRD) with the axial direction treatments: at the bottom, middle, and at the top portions with three replications. The statistical analyses were Anova with range tests at α = 5%, and Least Significant Difference (LSD) tests at α = 5%. The results showed that the treatments of physical properties (axial directions at the bottom, middle and top portions) were significantly different, except for the density of air-dried and oven-dried bamboo. The average of fresh moisture content was 73.73%, air-dried moisture content 12.56%; fresh volume density 0.68; air-dried volume density 0.80; oven-dried volume density 0.81.

Sifat kayu jati unggul nusantara (Tectona grandis L.f.) pada tiga kelas diameter pohon

Increasing the growth rate of teak trees is carried out to shorten the tree harvest rotation and reduce the deficit of teak timber supply, while maintaining the superiority of wood properties. The study was conducted to study the nature offive-year-oldJUNTeak wood in three classes of tree diameter and radial position of the trunk.This study employed a completely randomized design arranged in factorial combinations of the treatments of radial positions and diameter classes consisting of large (18-22 cm), medium (14-18 cm) and small (10-14 cm) stem diameters, andthe radial position of wood on the trunk based on the tree's ring. Three samplesof trees werefelled for each stem diameter classso that totally nine trees were used in this study. The testing of the physical properties of wood and the measurement of fiber dimensions were conducted using British Standards 373 and the IAWA method, respectively. The results showed that the diameter of the tree and the radial position of the wood had a significant effect on all parameters observed (fiber dimension and physical properties of wood), except the fiber diameter. The tree growth rate had a negative correlation with fiber length (-0.67), fiber wall thickness (-0.65), air-dry moisture content (-0.91) and air dry specific gravity (-0.86), and had a positive correlation with fiber diameter (0.61) and greenwater content (0.78). According to the pattern of wood properties in the radial direction, JUN wood harvested at the age of five was categorized as juvenile wood.This wood is acceptable as furniture and lightweight construction material.

Effect of moisture on energy-size reduction of lignite coal in Hardgrove mill

The effect of moisture on Shengli lignite breakage behavior and energy efficiency was studied experimentally using a standard Hardgrove mill fitted with a wattmeter. The grinding process concerned both the inputs, namely the occurrence and content of water and instantaneous energy consumption and the outputs, size-reduction and product fineness. Results show that the energy-size reduction process for grinding lignite is markedly influenced by moisture occurrence and content. Removing surface moisture from 37.90% to 16.61% (the air-dried condition) resulted in a slight increase of input energy by 0.04 kWh.t−1 per 10 s. However, with further drying inherent moisture to 0%, the consumed energy significantly increased by 0.16 kWh.t−1 per 10 s. Meanwhile, the mass fraction remained on top size decreased from 42.29% to 24.73% and then to 13.00%, while the pulverized coal production increased sharply from 6.28% to 10.68% and to 23.64%, both at a grinding time of 6 min. The energy efficiency was also significantly improved as the moisture content of lignite was reduced to below the air-dried level. The air-dried moisture content was the inflecting point for lignite grinding in the Hardgrove mill. A two-stage pre-drying system was proposed accordingly.

KARATERISTIK SIFAT FISIKA BAMBU TALI (GIGANTOLOCHLOA APUS KURZ ), SEBAGAI BAHAN BAKU BAMBU KERAJINAN

The centre of bamboo crafts in Gunung Sari District is the largest bamboo centre in West Lombok Regency. One of the bamboo species which is usually used as raw materials is tali bamboo. Studies of physical properties of this bamboo have not been carried out resulting poor quality of bamboo crafts. The physical property was essensial information which would be used for enhancing the products because it correlated with dimensional stability of the bamboo. The objectives of this study were to identify the physical properties of the bamboo with reference to the axial direction. The experiment design was complete random design employing the axial directions (bottom, middle, and top portions) as treatments. The statistical analyses were Anova with range tests at α = 5%. The results showed that the physical properties were: fresh moisture content 51-119.82%; air-dried moisture content 13.03-15.04%; fresh volume density 0.51 – 0.72; air-dried volume density 0.62 – 0.75; oven volume density 0.63 – 0.78. Axial directions of the physical properties were not significantly different except for the fresh moisture content. Therefore all portions of tali bamboo (bottom, middle, and top portions) could be utilized as raw materials for bamboo crafts.

Several physical properties of Eucalyptus pellita F. Muell from different provenances and sampling position on tree

Eucalyptus pellita F. Muell is one of the species selected for the development of the plantation forest in Indonesia. In order to obtain a superior plant for the continuity of the plantation forest program, various tree breeding techniques are often applied, one of which is through best provenance selection. Conventional or advanced tree breeding program generally aims to obtain a fast-growing plant with good physical appearance. The program rarely gives attention to the properties/characteristics of timber produced. This aspect becomes the main background of this particular study which aims to investigate the effect of four provenances and also to examine the effect of sampling position on the trees on several physical properties of E. pellita . The result showed that the highest moisture content (97.34 + 15.67%) was found in the bottom part of trees from Indonesia provenance. While, the highest air-dry moisture content (15.15 + 0.20%) was observed in the top-part samples from Provenance North Kiriwo PNG. Samples from Provenance Serisa Village PNG have the highest density ranges, approximately 590 + 90 kg/m 3 and 630 + 80 kg/m 3 in the bottom-part samples and in the top-part samples, respectively. The highest T/R ratio, approximately 1.91 + 0.26, was observed in the bottom-part samples from Provenance South Kiriwa, PNG. The T/R ratio values of all provenances were less than 2, indicating the lumber will be possibly stable during its uses or further processing. Further result showed provenance factor significantly affect initial moisture content and density. Sampling position on trees only affect affects the initial moisture content. Based on the results, the timber of E. pellita being examined can be further used for light-to-medium construction purpose.

Pengaruh Posisi pada Batang terhadap Sifat Fisik dan Dimensi Serat Kayu Gmelina Hasil Penjarangan (The Influence Of Stem Position On Physical Properties And Fiber Dimension Of Gmelina From Thinning Activity)

Gmelina arborea Roxb. is a native species to Bangladesh, Cambodia, Southern China, India, Japan, Laos, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam, and Indonesia. Its regional name includes Gamar, Yemane, Khamari, White Teak, Gmelina, and Melina. For commercial purposes, gmelina can be reasonably developed for industrial forest plantation or community forest plantation in Indonesia based on its wood characteristics. The objectives of this study were to determine the physical properties and fiber dimension of wood procured from thinning activities. The research showed that the oven and air dried density, air dried specific garvity, and air dried moisture content of the gmelina wood were 0.38 g cm -3 , 0.44 g cm -3 , 0.37 and 19.82% respectively. The average of the fiber length, fiber diameter, lumen diameter and cell wall thickness were 820.13, 27.16, 21.13, and 3.01 µm, respectively. The differences in position on the stem affect the density, specific gravity and fiber length, in which the higher position of the stem, the lower of their values. But it does not affect the air dry water content, the fiber diameter, lumen diameter and cell wall thickness. Keywords : fiber dimension, Gmelina a rborea , physical properties, thinning, wood utilization

Application of mid-infrared spectroscopy for rapid characterization of key soil properties for engineering land use

Methods for rapid and accurate soil tests are needed for the index properties of material attributes commonly applied in civil engineering. We tested the application of mid-infrared (MIR) spectroscopy for the rapid characterization of selected key stability-related soil properties. Two sample sets, representing different soils from across Lake Victoria basin in Kenya, were used for the study: A model calibration set (n=135) was obtained following a conditioned Latin hypercube sampling, and a validation set (n=120) was obtained from independent sites using a spatially stratified random sampling strategy. Air-dried ground (<0.5mm) soil was scanned using a high-throughput screening accessory for diffuse reflectance attached to a Fourier transform infrared spectrometer. The soil properties were calibrated to smoothed first derivative MIR spectra using partial least-square regression (PLS), and screening tests were developed for various limitation classes applicable in civil works using the soft independent modeling of class analogy (SIMCA). The hold-out full cross-validation coefficient of determination (r2)≥0.8 was obtained for the liquid limit (LL), linear shrinkage (LS), coefficient of linear extensibility (COLE), air-dried moisture content, (W) and cation exchange capacity (CEC). Further independent validation gave r2≥0.73 and the ratio of prediction deviation (RPD) 4.4–2.1 for LL, LS, COLE, W, CEC, plastic limit (PL), plasticity index (PI), and volumetric shrinkage (VS). The independent validation likelihood ratios for the diagnostic screening tests were: LL>55%, 4.2; PI>30%, 2.7; LS>12%, 2.4; exchangeable sodium (eNa)>2cmol (+) kg−1, 2.3; exchangeable sodium percent (ESP)>10%, 1.8; W>8.3%, 1.6, and Activity number (A)>1.25units, 1.5. MIR can provide the rapid assessment of several soil properties that yield stability indices in material testing for engineering land use. Further studies should test the ability of MIR PLS for establishing broader calibrations across more diverse soil types and the direct correlation of MIR to material functional attributes.

Density, some anatomical properties and natural durability of stem and branch wood of two tropical hardwood species for ground applications

As wood resources deplete, branchwood is being promoted to supplement stemwood in Ghana, but its natural durability, which indicates its service life and can influence its acceptance and use is scarcely studied. This study compares the natural durability and some anatomical properties of branchwood and stemwood of Entandrophragma cylindricum (sapele) and Khaya ivorensis (mahogany) using Ceiba pentandra stemwood as control. Natural durability test followed field test method according to European Standard EN 252 1989 in combination with percentage weight losses while the anatomical investigations followed IAWA Committee 1989 recommendations. For each species, two branch logs were cut from each of two sampled trees from two natural forests in Ghana. Stemwood was also obtained from the same forest reserves as the branches. All sample groups were tested at air-dried moisture content of 14 ± 2 % as specified in the standard. Branchwood of both species were denser than their stemwood, but in addition to mahogany stemwood they were rated “non-durable”, while sapele stemwood was rated moderately durable. Thus at 5 % significance level, natural durability of mahogany branchwood appeared comparable to that of its stemwood whereas sapele branchwood was significantly less durable than its stemwood but more durable than Ceiba stemwood. Branchwood and stemwood vessels diameter and proportion also were significantly different (p < 0.1). Expectedly, density correlated positively with natural durability, but the correlation among anatomical properties, natural durability and density were stronger in stemwood than in branchwood. In conclusion, stem and branchwood of mahogany are both non-durable but sapele stemwood appears better than its branchwood for ground applications. Anatomical properties of stemwood influenced natural durability more than those of branchwood. For better acceptance of branchwood of the species for wood products manufacturing, further research would be necessary for additional data on their toxic extractive levels, mechanical properties and durability at different sites or/and using other drying methods.

Rapid estimation of soil engineering properties using diffuse reflectance near infrared spectroscopy

Materials testing involve complex reference methods and several soil tests have been used for indexing material functional attributes for civil engineering applications. However, conventional laboratory methods are expensive, slow and often imprecise. The potential of soil diffuse reflectance near infrared (NIR) spectroscopy for the rapid estimation of selected key engineering soil properties was investigated. Two samples sets representing different soils from across the Lake Victoria basin of Kenya were used for the study: A model calibration set (n = 136) was obtained using a conditioned Latin hypercube sampling, and a validation set (n = 120) using a spatially stratified random sampling strategy. Spectral measurements were obtained for air-dried (<2 mm) soil sub-samples using a Fourier-transform diffuse reflectance near infrared (NIR) spectrometer. Soil laboratory reference data were also obtained for liquid limit (LL), plastic limit (PL), plasticity index (PI), linear shrinkage (LS), coefficient of linear extensibility (COLE), volumetric shrinkage (VS), clay activity number (Ac), total clay content, air-dried moisture content, and cation exchange capacity (CEC). Soil reference data were calibrated to smoothed first derivative NIR spectra using partial least squares (PLS) regression. At the calibration stage, coefficient of determination for full cross-validation (R2) of ≥0.70 was obtained for CEC, mc, LL, PI, LS, COLE and VS. Further independent validation gave R2 ≥ 0.70 and RPD (ratio of reference data SD and root mean square error of prediction) 1.7–2.2 for LL, PI, mc and CEC. The results suggested that NIR–PLS has potential for the rapid estimation of several key soil engineering properties. Further work should focus on extending calibration libraries using more diverse soil types and testing alternative infrared diffuse reflectance based methods.

Study on Critical Moisture Content of Unsaturated Evaporation

Thin layer evaporation tests of three types of soil were conducted by a newly designed humidity-controllable evaporation and penetration measuring system and lasted for 8 days. The whole process of sample mass variation from wet to dry was recorded in the laboratory. The critical moisture content and air-dried moisture content were obtained from evaporation curve, which divided the evaporation process of thin layer unsaturated soil into three stages, including stable rate stage, reducing rate stage and residual stage. The soil water characteristic curves of soils were predicted by Arya and Paris model, the results showed that the critical moisture contents of evaporation process were the same with the water contents corresponding to residue values of SWCC, it is significant to studying on unsaturated evaporation process.