Explosion pulping of eucalyptus: a comparison with CTMP and CMP

Summary Explosion pulping results in strong pulp with breaking length at 100 ml CSF (Canadian standard freeness) higher than 6.5 kg and burst index approaching 4 KPa m²/g. The real advantage of eucalyptus explosion pulp over conventional CMP (chemical-mechanical pulp) and CTMP (chemical-thermo-mechanical pulp) is observed when the impregnation solution contains less than 2% NaOH along with 8% Na₂SO₃, and when the liquor/chips ratio equals 3. The strength of eucalyptus explosion pulp obtained by using a pretreatment solution consisting of 8% Na₂SO₃ and 1% NaOH is comparable with that of eucalyptus kraft pulp. The concentration of NaOH present in the pretreatment solution has a very important effect on the specific refining energy of eucalyptus explosion pulp as well as of CMP and CTMP. The explosion pulp obtained from eucalyptus pretreated with a solution containing an appropriate quantity of caustic along with Na₂SO₃ not only requires a minimum specific refining energy but also provides the highest strength values in comparison to that of CMP and CTMP.     

Industrial utilization of tobacco stalks II: preparation and characterization of tobacco pulp by steam explosion pulping

Our previous paper showed tobacco stalks to posses the characteristics of a raw material for pulp and paper application. It contains the major biomass constituents and cell components common to wood species. In this study, preparation and characterization of tobacco stalk pulp by steam explosion (SE) pulping at two chemical pretreatments were attempted. Chemical pretreatment prior to SE pulping improved the brightness, yield, and strength properties of the resulting tobacco SE pulps in the order: 6% Na₂SO₃ + 1% NaOH > 6% Na₂SO₃ > control (untreated). The 6% Na₂SO₃ + 1% NaOH-impregnated tobacco stalks produced SE pulps of good fiber length distribution and considerable properties that compare well with pulps from other raw materials obtained from previous studies, and the nonimpregnated ones showed strength properties superior to those of their poplar counterpart. Prior to bleaching, pretreating the tobacco stalk SE pulps with two stages, 2% NaOH at 90°C, improved the initial pulp brightness by about 5 points. Two-stage 6% H₂O₂ bleaching gave a comparable effect with hypochlorite bleaching for both tobacco and poplar, giving a 29–34 brightness point increase for tobacco SE pulp and 61 for the poplar samples. The differences in the bleaching responses for untreated tobacco and poplar SE pulps were attributed to the differences in their lignin structure, as shown in the total yield of their respective nitrobenzene oxidation products and FT-IR spectra. Tobacco SE pulps contain more of the guaiacyl-type lignin and poplar the syringyl-type lignin.This paper was presented in part during the 1998 CORESTA (Cooperation Centre for Scientific Research Relative to Tobacco) Congress, Brighton, UK, October 1998     

Na2O-SiO2 wood-inorganic composites prepared by the sol-gel process and their fire-resistant properties

For enhancing fire-resistant properties, a binary system to prepare wood-inorganic composites was studied by adding sodium methoxide (SM) or sodium acetate (SA) to a reaction system for SiO₂ composites. Compared with the SiO₂ composites, both the Na₂O-SiO₂ composites prepared could be greatly improved up to 600°C-700°C (glowing). From scanning electron microscopic observations, this enhanced fire resistance was assumed to be due to chemical and physicochemical effects, such as dehydration and carbonization of wood by Na₂O gel. The glassy layer and intumescent structure formed over the cell walls were thought to prevent oxidation and heat transfer from proceeding into the inner portion of the wood cell walls. However, the reaction medium with SM to prepare Na₂O-SiO₂ composites was basic, whereas that with SA was rather neutral. In addition, in the latter composites, most of the inorganic gel was formed within the cell wall, retaining the porous structure characteristic of wood. Therefore, the Na₂O-SiO₂ composites prepared with SA can be concluded to be preferable for practical purposes.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000     

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR characterization of chestnut (Castanea sativa) shell tannins for wood adhesives

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR techniques were used to analyse the structure of non-purified aqueous chestnut shell tannin extracts. In addition, the influence of the extraction agent (water or aqueous solutions of Na₂SO₃ and/or NaOH) on tannin structure was analysed by MALDI-TOF in order to select the extract with the best properties for wood adhesives. Using HPLC-ESI-TOF, catechin/epicatechin, gallocatechin/epigallocatechin, dicatechin structures, dicatechin structures without a hydroxyl group, galloyl-glucoses and ellagic acid were identified as the main monomeric components in the aqueous extract. 13C-NMR and MALDI-TOF spectra revealed that extracts are mostly composed of procyanidin and prodelphinidin structures although prorobinetidins might be also present. MALDI-TOF spectrometry was used to identify the extract oligomeric components. Extractions with Na₂SO₃ and/or NaOH produced changes in the predominant structures in the extracts and on the amount of sugar units linked to the flavonoid structures, which decreased in the presence of Na₂SO₃. Extract obtained using low Na₂SO₃ and NaOH concentrations (1.5 and 0.75 %, respectively) was selected as more suitable for wood adhesive preparation.     

Responses of germination and radicle growth of two Populus species to water potential and salinity

The effects of water potential, NaCl and Na2SO4 on germination and radicle growth of two riparian tree species, Populus euphratica Oliv. and P. pruinosa Schrenk (Salicaceae), were tested. Growth chamber studies revealed an optimum temperature range for seed germination of both species between 15-35℃. The final germination percentage of both species decreases with decreasing water potential in all types of solution applied in the experiments. P. pruinosa was less tolerant to low ψw stress than P. euphratica, especially in salt solutions. Germination percentages fell below 20% for P. pruinosa at -0.6 MPa (NaCl) or -0.4 MPa (Na2SO4) and for P. euphratica at -1.2 MPa (NaCl) or-0.6 MPa (Na2SO4). Radicle growth of both species was inhibited by high concentrations of PEQ NaCl and Na2SO4. However, growth was enhanced at -0.13 and -0.29 MPa in PEG or at -0.13 MPa in NaCl solutions compared to distilled water. Radicle growth of P. euphratica was higher than that of P. pruinosa. Germination and radicle growth of both species exhibited ion toxicity. Na2SO4 was more toxic than iso-osmotic solutions of NaCl. Radicle growth proved to be more sensitive than seed germination. Thus, flooding does not only yield the necessary soil moisture for germination but also favors seedling establishment of both species through leaching of salts from the soil surface. The different sensitivity of the species during their early growth stages might, moreover, contribute to the observed differences in their distribution in the Talim Basin (northwest China).     

广州市酸雨对不同森林冠层淋溶规律的研究

１９９８年４月至１９９９年３月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测,并测定和分析了林内穿透雨物理量及化学量,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明：（１）广州市酸雨占次数的７９．７％或占降雨量的９５．１％。（２）酸雨通过林冠层后,ｐＨ值明显增加。（３）在马尾松林和常绿阔叶林中,某些单次降雨出现ＳＯ４＾２－、ＮＯ３＾－、ＮＨ４＾＋Ａｌ＾３＋、Ｎａ＾＋的负淋溶现象,说明森林对这些离子（特别是ＮＯ３＾－、Ａａ＾３＋）具有吸收作用;阔叶林全年的ＮＯ３＾－和Ａｌ＾３＋净淋溶为负值,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。（４）雨水酸度增加（即ｐＨ值减小）,明显提高阳离子Ｃａ＾２＋、Ｍｇ＾２＋、Ｋ＾＋和Ｎａ＾＋冠层淋溶面分率。（５）ＮＨ４＾＋、ＳＯ４＾     

Inhibitory factors ofArgas (Argas) reflexus (Fab.) (Acari,Argasidae) larvae development

The eggs ofArgas reflexus were splashed with the LiCl and Na₂Cr₂O₇ saturated solutions on the 2nd day after laying and were kept at 25° C and 30% RH.Both examined chemical compounds caused great disturbances in embryogenesis ofArgas reflexus. Under influence of Na₂Cr₂O₇ 24.8% eggs died. The LiCl solution appeared to be more harmful on larvae development. 21.8% dead eggs, 11.6% dead embryos, and 8.9% larvae hatched abnormally were observed in these experiments

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Zusammenfassung Hemmende Faktoren bei der Embryonalentwicklung vonArgas (Argas) reflexus (Fab.) (Acari, Argasidae)Die Eier vonArgas reflexus wurden am 2. Tag der Embryonalentwicklung bei 25° C und 30% r. L. der. Wirkung gesättigter Lösungen von LiCl und Na₂Cr₂O₇ unterzogen.Beide chemischen Verbindungen verursachten große Störungen der Embryogenesis vonArgas reflexus. Unter dem Einfluß von Na₂Cr₂O₇ starben 24.8% der Eier ab. LiCl erwies sich als schädlicher für die Embryonalentwicklung dieser Zeckenart als Na₂Cr₂O₇.Bei den Experimenten mit LiCl wurden 21.8% Eier, 11.6% Embryos und 8.9% (abnormal geschlüpfte) Larven getötet.

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With one table     

重庆酸雨区缙云山典型林分冠层酸雨淋洗特征

选取重庆缙云山的针阔混交林、常绿阔叶林、毛竹林、灌木林4种典型林分,观测酸性降水过程中林外雨、穿透雨及干流等林内水分转换分量中的主要离子含量变化,分析林分冠层对雨水化学组成的影响,结果表明:(1)降雨中的离子当量浓度大小依次是SO42-＞Ca2+＞ NH4+＞Mg2+＞K+＞Na+＞NO3-;(2)降雨经过林冠层后pH值降低,干流的酸化程度增加最大;(3)降雨经林冠层后离子浓度明显增加(除灌木林),穿透雨中通量增加最大的阴离子和阳离子分别为SO42-(2.19×103～6.47×103 eq·hm-2)和Ca2+(1.41×103～3.39×103 eq-hm-2),离子来源主要为大气沉降和植物分泌物或淋出;(4)同一离子在不同林分的干流和穿透雨中的通量变化不同,反映出不同林分冠层的离子交换性差异.在针阔混交林中,林下降雨净淋溶量大小顺序为SO42-＞Ca2+＞ NO3-＞K+＞NH4+＞Mg2+＞ Na+;常绿阔叶林为SO42-＞ Ca2+＞ K+＞NO3-＞ NH4+＞ Mg2+ ＞Na+;毛竹林为Ca2+＞ SO42-＞ K+＞NO3-＞ NH4+＞Na+＞Mg2+;灌木林为Ca2+＞ NO3-＞ K+＞ Na+＞Mg2+＞ NH4+＞ SO42-.     

Water quality of Kaptai reservoir in Chittagong Hill Tracts of Bangladesh

A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na+, Ca2+, Mg2+, SO42-, Cl-, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO42-, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na+ and HCO3- contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca2+, Mg2+ and Na+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.     

Modeling internal temperature changes of timber poles during ACA treatment

Summary The temperature-time-location relationships during steam conditioning and pressure treatment of timber poles using ammoniacal copper arsenate (ACA) have been studied and a new mathematical model that incorporates both the thermal properties of the poles and the parameters of the treatment process is discussed. Prediction equations and charts are presented that show the minimum required steaming time to satisfy the 1982 Rural Electrification Authority (REA) purchase specification, i.e. a center temperature above 150 °F (65.5 °C) for 2 hours. A six hour steaming time, commonly used for ACA treatment, has been found to be too short to bring poles with diameters larger than about 40 cm to the required sterilization conditions. Therefore longer steaming times, predicted using the methods given here, are recommended. The temperature of the preservative used does not appear to be a major factor in determining the maximum temperature achieved at the center of a pole, but it can influence the length of time the pole is above 65.5 °C.Symbols D pole diameter, cm - k₁ rate of surface temperature change during vacuuming, °C/h - K₂ rate of surface temperature change early in the pressure period, °C/h - J₀ Bessel function of the first kind of order zero - J₁ Bessel function of the first kind of order one - r radial location in a pole measured from the center, cm - R pole radius, cm - T interior temperature of a pole during preservative treatment, °C - T_f final preservative temperature, °C - T_mid average of the steam and the final preservative temperatures, °C - t₀ initial temperature of a pole, °C - T_s temperature of the steam used for conditioning the poles, °C - T₁ surface temperature at the end of the vacuum period, °C - t time measured from the opening of the steam valve for steaming, h - t_above time the center of a pole remained above 65.5°C during preservatives treatment, h - t_c1 total time required for the surface temperature to reach T_f, °C - t_pr time elapsed at which initial vacuuming stops and pressure is applied, h - t_stm minimum required steaming time used, h - t_vc time elapsed at which initial vacuuming starts, h - thermal diffusivity, cm²/h - _n Roots of a particular characteristic equation - _d the time delay period between initial flow of steam and surface temperature response, h     

Buttock temperature in a sedentary posture on plywood flooring of varying thickness over the ONDOL heating system

This study investigated the thermophysiological responses of healthy subjects that sat on the plywood covering of the ONDOL floor heating system. Environmental chambers were constructed for this study, wherein ambient temperature, and wall and ceiling surface temperature were controlled at 24°C, and relative humidity was 50%. The temperature of supply water (t _sw) flowing into the floor coil was altered from 15°C to 40°C at 5°C intervals. The floor covering materials used in this experiment were mortar and three types of plywood with thicknesses of 2.7, 7.5, and 12mm. The floor surface temperatures (t _f) and the skin temperatures of eight subjects were measured while they were sitting on the floor. Buttock temperature, in particular, was monitored. This experiment yielded the following results: (1) t _f was 17.0°–35.2°C on mortar finishing and 19.1°–30.2°C on 12-mm plywood covering; (2) the buttocks skin temperature increased with t _sw higher than 30°C on mortar finishing and for t _sw higher than 30°, 25°, and 20° on 2.7-, 7.5-, and 12-mm plywood finishing, respectively; (3) the differences of buttock temperature when t _sw was varied between 15° and 40°C were 11.4°C on mortar, 7.9°C on 2.7-mm plywood, 6.5°C on 7.5-mm plywood, and 5.0°C on 12-mm plywood; (4) using regression analysis, the neutral point temperature of buttocks was determined to be 32.8°C.Part of this report was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, Japan, March 2003     

Extraction of antioxidants from eucalyptus (Eucalyptus globulus) bark

The extraction of phenolic compounds from eucalyptus (Eucalyptus globulus) bark was examined with the aim of analyzing the potential of the extracts as natural antioxidants. Experiments were planned according to a 2³ factorial design to analyze the influence of temperature and Na₂SO₃ and NaOH concentrations in aqueous solutions on extraction yield, extract total phenols content, ferric reducing antioxidant power (FRAP), and number- and weight-average molecular weights. Extract total phenols content and FRAP antioxidant activity in the ranges 0.91–2.58?g gallic acid equivalent (GAE)/100?g oven-dried bark and 4.70–11.96?mmol ascorbic acid equivalent (AAE)/100?g oven-dried bark, respectively, demonstrated the potential of eucalyptus bark as a source of antioxidant compounds. Extraction at the highest temperature (100°C), the lowest Na₂SO₃ concentration (1.5% on oven-dried bark), and without NaOH provided the highest extract total phenols content and FRAP antioxidant activity. Those eucalyptus bark extracts with lower molecular weight showed higher antioxidant activity. Matrix-assisted laser desorption ionization time-of-flight and reverse-phase high-performance liquid chromatography electrospray ionization time-of-flight mass spectrometry revealed the presence of polygalloyl glucoses, catechin, epicatechin, ellagic acid, quercetin-3-o-rhamnoside, and isorhamnetin in eucalyptus bark aqueous extracts.     

Distribution of sulphur fractions in lysimeters previously treated with sulphuric acid,NPK fertilizer and a combination of acid and fertilizer

The retention of applied ³⁵S was studied in a lysimeter experiment, in which the lysimeters, consisting of soil columns with intact field and groundlayer vegetation, had previously been treated with either sulphuric acid, NPK or a combination of sulphuric acid and NPK.³⁵S was applied as Na₂³⁵SO₄ to all lysimeters in an amount corresponding to 2 kg S ha^?1, 3 months before the termination of the experiment. Of the applied ³⁵S, 4.7 ± 1.6% (the error term showing the standard error of the mean) was leached from the lysimeters; ³⁵SO₄^2?, was preferentially sorbed in the upper part of the B horizon, >61% being sorbed in the B horizon as a whole. The influence of previous treatments was seen in SO₄^2? content in the B horizon and also in the SO₄^2? concentrations in the leachates from the lysimeters. Sorption of ³⁵SO₄^2? was enhanced by the acid treatment in the A₀ and A₁/A₂ horizons. Ratios between water-extractable SO₄^2? and KCl-extractable SO₄^2? varied from 0.88 in the A₁/A₂ horizon to 0.46 in the lower part of the B horizon, indicating a preferential sorption of less available SO₄^2? fractions in that part of the soil.Significant positive correlations between soil organic carbon and various sulphur fractions, both labelled and unlabelled, indicated the importance of biological S transformations in the A₀ and A₁/A₂ horizons.Positive correlations between KCl-extractable Al and KCl-extractable SO₄^2? were found in the B horizon. Equilibrium calculations suggested that the SO₄^2? activity and Al³⁺ activity in leachates from control and acidified lysimeters were within the stability fields of basaluminite (Al₄(OH)₁₀SO₄), activities in leachates from the latter group of lysimeters, also being close to jurbanite (Al(OH)SO₄).     

A positive growth response to NaCl applications in Eucalyptus plantations established on K-deficient soils

Contrasting responses of Eucalyptus trees to K fertilizer applications have been reported on soils with low K contents. A complete randomized block experiment was set up in Brazil to test the hypothesis that large atmospheric deposits of NaCl in coastal regions might lead to a partial substitution of K by Na in Eucalyptus physiology and enhance tree growth. Treatments with application of 1.5, 3.0, 4.5 kmol K ha⁻¹ (K_1.5, K_3.0, K_4.5, respectively) as KCl, 3.0 kmol K ha⁻¹ applied as K₂SO₄, 3.0 kmol Na ha⁻¹ (Na_3.0) as NaCl commercialized for cattle feeding, and a mixture of 1.5 kmol K + 1.5 kmol Na ha⁻¹ (K_1.5 + Na_1.5) were compared to a control treatment (C) with no K and Na applications. All the plots were fertilized with large amounts of the other nutrients.     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin III: effects of sodium chlorite treatment

To obtain high-strength phenol–formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO₂) treatment on wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO₂ solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO₂ treatment has shown considerable potential for high compression of PF resin-impregnated wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-impregnated veneer laminated composites that were treated with NaClO₂ four times and compressed at 1 MPa, reached 1.15 g/cm³, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-impregnated wood reached 0.8 g/cm³, 16 GPa, and 165 MPa, respectively.     

Canopy leaching of subtropical mixed forests under acid rain

Leaching of major ions from acid precipitation in a subtropical forest was examined based on an experiment in four sample sites in Shaoshan City, Hunan Province, China, from January 2001 to June 2002. Results clearly show that when rain passed through the canopy, pH increased and the evidence of ion uptake was presented for SO₄ ²⁻, NO₃ ⁻, Mg²⁺ and NH₄ ⁺ ions, especially of NH₄ ⁺ and NO₃ ⁻. The percentages of dissolved SO₄ ²⁻, Ca²⁺ and Mg²⁺ show a decreasing trend with increasing rainfall. Percentages of leaching Ca²⁺, K⁺ and Cl⁻ ions show an increasing trend as a function of increased pH values. The forest canopy in Shaoshan City has a strong effect on the uptake of SO₄ ²⁻ and NO₃ ⁻ ions under acid rain conditions. The decreasing order of ions leaching in the forest canopy is as follows: K⁺ > Ca²⁺ > Cl⁻ > Mg²⁺ > SO₄ ²⁻ > NO₃ ⁻ > NH₄ ⁺ > Na⁺. __________ Translated from Scientia Silvae Sinicae, 2007, 43(7): 1–4 [译自: 林业科学]     

Extensive study on forest runoff water chemistry over east Asia

The chemistry of runoff waters from 13 forested watersheds in six regions (four regions from Japan, one from southern China and one from northern Thailand) was evaluated. The Cl⁻ concentrations in runoff waters were higher in those watersheds which had closed canopies and were nearer to the ocean. The NO₃ ⁻ concentrations were higher in those watersheds having the developed soils and high moisture conditions, but were lower in tropical and subtropical regions for those watersheds which had high rates of nitrogen uptake and for watersheds with large areas of saturated soils. The SO₄ ²⁻ concentrations were affected by SO₄ ²⁻ adsorption properties of the soils: at Shibecha, Jiulianshan, and Chiang Mai with high adsorption capacities SO₄ ²⁻ concentrations in streams were low. High SO₄ ²⁻ concentrations were found at Mt. Hiei and Kagawa due to the weathering of sulfur minerals and high levels of atmospheric sulfur deposition. Within regions SO₄ ²⁻ concentrations were inversely related to NO₃ ⁻ concentrations. A comparison among the watersheds suggested H⁺ consumption in deeper soil that increased pH and HCO₃ ⁻ concentrations of the runoff waters of some watersheds. Anion concentrations increased with low H.I. (Humidity Index) values suggesting that dry conditions increased concentrations due to high rates of evapotranspiration.     

Influence of surface charge on viscosity behavior of cellulose microcrystal suspension

Microcrystalline cellulose with minimal surface charge was prepared from softwood kraft pulp via hydrolysis by 4N hydrochloric acid instead of sulfuric acid. To this material, sulfate ester groups as surface charge were introduced by treating with 55% (w/w) sulfuric acid. A treatment at 60°C for 2h gave nearly the same level of surface charge as that of the H₂SO₄ -hydrolyzed microcrystal. The number of sulfate groups were controlled by changing the H₂SO₄ treatment conditions. Although the microscopic size and shape of the microcrystalline particles were the same irrespective of the preparation method, the introduction of surface charge drastically reduced the viscosity and removed its time dependence. These changes in viscosity behavior are considered to result from charge-induced dispersion of loose aggregates existing in the initial charge-free microcrystals prepared by HCl hydrolysis.Part of this report was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

Characteristics of thermal decomposition of bamboo with different chemical additives

By means of the analysis of TG-DSC curves, we studied the effect of temperature and several additives, i.e., H₂SO₄, HCl, NaOH, H₂O₂ and H₃PO₄ on the performance of the thermal decomposition of bamboo. The results indicated that the weightlessness of pure bamboo powder may be divided into three stages, up to 700°C. At each stage, the effect of each chemical additive on the weightlessness rate of bamboo was different. In the end, we analyzed the function of additives in practical applications of the thermal decomposition of bamboo. __________ Translated from Journal of Bamboo Research, 2007, 26(1): 42–45 [译自: 竹子研究汇刊]     

Multiple modelling of water chemistry flows assessed in a mountain spruce catchment

The study was carried out over a period of 1999–2003 in the Dupniański Stream catchment located in Silesian Beskid Mts. Region (Southern Poland). Analysis of the chemical composition of bulk precipitation, throughfall, stemflow, surface flow, soil water (horizontal + vertical and vertical penetration) and outflow water samples was performed. The complex data matrix with more than 3,000 observations of water reaction, major anions (F⁻, Cl⁻, NO₃ ⁻, SO₄ ²⁻) and cations (NH₄ ⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe²⁺, Mn²⁺ and Zn²⁺) were treated by regression modelling. The modelling approach took into account seasonal variability according to winter and growing season, as well as chronosequence of spruce stands. The retention of considerable levels of contaminants by the canopy, and their removal or washout from needles by rainfall caused changes in the concentration of anions and cations reaching the soil surface compared to the concentrations in bulk precipitation. In the youngest stand, most elements except NH₄ ⁺, SO₄ ²⁻ and K⁺ were retained in the canopy, and even H⁺ ions were neutralized. In the older stands, most elements increased in net throughfall fluxes, and the acidity increased strongly. Soil water was slightly correlated with throughfall, while outflow water showed no correlations with the above ground water flows, and seemed to depend mostly of the bedrock.