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1.
The sulfate soap Is refined through extracting unsaponlfiablc neutral substan比usingethyla以tatc and hcxanc—acctonc.The contentofncutralsubstancelntallolldccreasesfrom32.8%to 7.4%and 18%The acid number oftalloilincrcascsfrom!19to!69and!53Thequalityoftall oil Is greatly improved.ThlSprovides a favorable condition for distillation of tall oil.Theunsaponlfiablc neutral substancenom crude sulfate soap mainly consists of tcrPCnc aldchydcs,Icrpcnc alcohols,fatty alcohols and sterols Inwhlch larlxol Is 26.3%and 18.5%;sterols arc 17%and 27.l%M paratcly.The wb!to crystals containing sterols of96.9%are obtalncdbycrystalhaatlonand rccrystalllzatlon The sterols arc mainly g一sltostcrol and campcsterol.  相似文献   

2.
Storage of non-dormant seeds of Fraxinus angustifolia Vahl   总被引:1,自引:0,他引:1  
Piotto  Beti 《New Forests》1997,14(2):157-166
The effects of drying and storage on the quality of Fraxinus angustifolia non-dormant seeds have been investigated. Mature seeds subjected to a 2-week warm stratification (20 °C) followed by a 2-week cold stratification (3 °C), were exposed to a gentle air stream at room temperature to dry them to 9.5% moisture content. After 4, 8 and 12 months of storage at –3 °C, in hermetically sealed containers, germination tests were conducted in darkness at 30/20 °C and 25/5 °C to evaluate possible changes in seed quality. The results obtained suggest the feasibility of drying non-dormant seeds. In fact, though causing a slight decrease in seed quality, such a process enables storage of ready to sow seeds for at least 12 months without any further loss. The temperature regime of 30/20 °C, prescribed by the International Seed Testing Association (ISTA), was found to be suboptimal for the particular conditions tested in this trial, the 25/5 °C cycle being more stimulating for germination.  相似文献   

3.
利用响应曲面法( RSM)优化超声-微波辅助提取秦岭龙胆挥发油的工艺条件。在单因素实验基础上,选取超声功率、微波功率、提取时间、液固比为自变量,以乙醚为浸提溶剂,挥发油得率为响应值,应用中心组合实验设计方法,研究各自变量及其交互作用对挥发油得率的影响,建立二次多项回归方程预测数学模型。结果表明,超声功率、微波功率和提取时间3个因素对挥发油提取率有显著影响。确定超声-微波辅助提取秦岭龙胆挥发油的最佳工艺参数超声功率270 W,微波功率570 W,液固比25 mL/g,提取时间11 min,在此条件下,挥发油的提取率达到了7.183%。  相似文献   

4.
研究了超临界CO2流体萃取柑橘皮精油的工艺条件并对其化学成分进行了分析。考察了在超临界CO2条件下,萃取时间、萃取压力、萃取温度、CO2流量和分离温度等因素对精油得率的影响,并通过正交试验优化得到最佳工艺条件,用GC-MS法测定柑橘皮精油的化学组成。结果显示最佳工艺条件为:萃取温度40℃,萃取压力20 MPa,分离温度50℃,萃取时间60 min,CO2流量25 kg/h。在此条件下,精油得率为0.86%。GC-MS测定结果显示柑橘皮精油主要由5,5’-二甲氧基-3,3’-二甲基-2,2’-联二萘-1,1’,4,4’-四酮组成(35.54%),其次还含β-羟基-甲基炔诺酮-甲基肟(24.60%)。  相似文献   

5.
The residue from tall oil distillation, known as tall oil pitch (TOP), was investigated by GC/MS analysis. Several separation techniques such as preparative TLC and extractions from solutions of different pH were applied. Apart from about 4% distilled free acids (fatty and diterpenoid) and 5% steroids (sitosterol and sitostadiene) two new fatty acids C-26 and C-28 could be detected. About 1% of lignin like material could be isolated after continuous extraction with chloroform.The authors wish to express their gratitude to the Österreichische Nationalbank for financially supporting the purchase of the gas chromatographic equipment. The authors also thank Dr. A. Nikiforov for providing the mass spectroscopical equipment  相似文献   

6.
Synthesis conditions of terpene-phenol-aldehyde resin with a high softening point were studied based on the reactions among-pinene, phenol, and formaldehyde. A suitable catalyst system and the best processing conditions were obtained by laboratory experiments. The influence of the raw materials ratios, reaction temperature, reaction time, and catalyst dose on the softening point, yield, and color of the synthesized resin was examined. The physical and chemical characteristics of the resin were determined: softening point 140°C (ball and ring method); color value 7 (Gardner); acid value (KOH mg/g) <1; bromine value (Br2 mg/100g) <64; saponification value (KOH mg/g) <1; average molecular weight 830. The yield of resin was more than 85% (based on the total raw material).  相似文献   

7.
The equilibrium moisture content (EMC) of six wood species under desorption conditions of 20°C and 100% 0% relative humidity (RH), and the rate of adsorption at various depths of three wood species blocks under 98% RH at 22.5°C were studied. There were no significant differences among the EMC values for these six wood species over the RH range 40% 0%, but there were highly significant differences over the RH range 100% 50% at constant 20°C. The amount of moisture absorbed in the wood decreased curvilinearly with the increase of depth in the specimens as sorption time increased, and their relation could be represented by a semilogarithmic equation. Time-dependent adsorption behavior at various depths of the wood specimens could be represented by an exponential equation as a function of the product of the difference between moisture contents at equilibrium and initial conditions and the term (1 – e–t/). The value of of various wood species was found to increase linearly with the increased depth of the specimen and showed the following trend: hard maple (Acer sp.) > China fir (Cunninghamia lanceolata) > Japanese cedar (Cryptomeria japonica D. Don).Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997.  相似文献   

8.
Dielectric properties of hardwood species at microwave frequencies   总被引:2,自引:0,他引:2  
Dielectric measurements at 9.8GHz and 2.45GHz were made for the three hardwoods Euramerican hybrid poplar, alder, and oriental beech. The method used was based on Von Hippels transmission line method. The measurements were carried out at room temperature of 20°–24°C. The dielectric properties of the wood species were determined for the three principal structural directions at six different moisture conditions, covering the range of 0% to 28% moisture content. Results indicated that the behavior of all wood species studied is quantitatively similar. In general, the dielectric properties increase within the range studied with rising moisture content. The grain direction of the wood also plays a significant role.  相似文献   

9.
为高效利用圆齿野鸦椿籽油,采用正己烷加热回流提取圆齿野鸦椿籽油,分别考察了提取时间、提取温度和正己烷-圆齿野鸦椿籽粉末比(液料比)对圆齿野鸦椿籽油提取得率的影响。以单因素试验的结果为依据,运用Design-Expert 8.0.6软件进行Box-Behnken响应面设计及数据分析,进一步对回流提取圆齿野鸦椿籽油的工艺进行优化。研究结果表明:各因素影响提取得率的主次顺序为提取时间、提取温度、液料比;最佳提取工艺是加热回流提取时间62.04 min,提取温度80.2℃,液料比10.14∶1(mL∶g),该条件下提取得率的预测值为5.84%,通过验证实验发现,提取得率实验值为(5.85±0.001)%,与预测值接近,两者的相对误差为0.17%,说明响应面优化的圆齿野鸦椿籽油提取工艺稳定、可行。同时,对圆齿野鸦椿籽不同部位提取得到的油脂进行分析,种仁出油率为(35.6±0.7)%,种皮出油率为(2.1±0.15)%,对籽油成分进行分析,检测出18种脂肪酸成分,其中不饱和脂肪酸达到65.52%,亚油酸的量最高,达45.64%。  相似文献   

10.
Protein, oil, carbohydrate and starch contents of seed, which were collected from places with latitude 9° N to 32° N, longitude 72° E to 85° E and rainfall 40 to 400 cm, varied significantly (P<0.05) among 12 provenances. Interestingly, seed protein was positively correlated (r=0.838,P<0.05), and on the contrary, carbohydrate and starch were negatively correlated (r=–0.755,r=–0.623, respectively,P<0.05), with the latitude of the seed source. Significant variation for N, P, K, Ca and Mg in stems and leaves of one-year and three-year-old plants was also observed when these provenances were grown at Hisar (29°10 N, 75° 46 E, 215 m alt.), an arid region in north India. In general, provenances from north India at the age of three years had greater chemical and mineral contents than those from south India. Chlorophyll content was highly correlated with the latitude of the seed source, at the ages of one and three years (r=0.742,r=0.659,P<0.05, respectively), while crude protein of foliage at the age of three years was significantly correlated (r=0.673) with latitude. Dehradun, Jammu and Hisar provenances, from the north had comparatively greater concentrations of N, P and K at the age of three years as compared to those from south India. The results are useful from the points of view of genetical variation, and selection of superior provenances for arid conditions in north India.  相似文献   

11.
Six wood species were carbonized under various carbonization temperatures and nonoxygen conditions to obtained charcoal. The effects of wood species, rate of temperature rise, and carbonization temperature on the electromagnetic shielding efficiency (ESE) of the electric field were investigated. The wood species used in this study were Japanese cedar, China fir, western hemlock, red oak, fortune paulownia, and Taiwan acacia. Tested materials were carbonized in a high-temperature oven under the following conditions: rate of temperature rise 1°–5°C/min; carbonization temperature 500°–1100°C, with temperature intervals of 100°C; maximum temperature maintained for 1h; and flow rate of nitrogen 300ml/min. The electromagnetic insulation strength system was used to detect the ESE of the electric field of charcoal. It was found that western hemlock and fortune paulownia charcoal showed maximum ESE values of of 36 and 61dB generated at a carbonization temperature of 1000°C. The charcoals derived from four other wood species showed maximum ESE values of 28dB for Japanese cedar, 23dB for China fir, 32dB for red oak, and 38dB for Taiwan acacia, respectively, at a carbonization temperature of 1100°C. The ESE value for fortune paulownia charcoal was similar to those of metal nets. The relations between ESE and logarithmic values of resistivity (log) could be represented by a negatively exponential formula.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000  相似文献   

12.
Sacandé  M.  Pritchard  H.W.  Dudley  A.E. 《New Forests》2004,27(3):239-250
Prunus africana, from the moist highlands of sub-Saharan Africa, is subject to great exploitation because its bark is used in the treatment of prostate-related diseases. A better understanding of the biology of its seed could help the ex situ and in situ conservation of the species. Fifty per cent of fresh seeds (46.8% MC) from mature purple fruits harvested in Kenya germinated after 10 days incubation at 25°C. The germination rate was linearly related to constant temperature, giving a prediction for the minimum temperature for germination at ca. 0.6°C. All seeds germinated at 5°C during 4 months fully hydrated storage. P. africana seed is, thus, neither dormant nor chilling sensitive. The relationship between equilibrium moisture content and relative humidity was used to construct a sorption isotherm, against which seed desiccation and storage responses were assessed. Seventy six per cent of mature seeds survived drying to 4.5% MC (22% RH) compared to 17% of seeds from immature purple-green fruits. Although, 25–45% of mature seeds survived at 8–12% MC after 2 months, only 10% remained viable after 6-month storage at 5°C. This study proposes optimum conditions for the artificial regeneration of P. africana seeds and highlights the need for further experiments storing dry seeds at sub-zero temperatures.  相似文献   

13.
The purpose of this study was to investigate the effects of changes in the helical angle of the router bit on the acoustic emission (AE) signal for various workpiece grain angles. The helical angle varied from 0° to 50° at 10° increments. The workpiece grains were oriented from 0 degrees (cutting parallel to the grain), through 90° (cutting end of the grain), to 165° at 15° increments. The AE signals and machined surface roughness were measured in an attempt to clarify the relations between them. The results were summarized as follows: (1) The AE signals were lowest in the with the grain cutting zones and slightly increased in the against the grain cutting zones; they rapidly reached the highest values at the 135°–165° grain angles. The greater the helical angle of the router bit, the smaller were the AE count rates for each grain angle investigated. There was no significant change in AE generation for helical angles of 0° and 10°. Moreover, the greater the feed rate, the greater was the AE count rate for every cutting condition investigated. (2) The surface roughness, similar to the AE count rate, had the lowest values in the with the grain cutting zones, slightly increased until the 120° grain angle, and then rapidly become extremely rough, reaching a maximum at the grain angles of 135°–150°. There was no remarkable change in the machined surface roughness while routing with the grain using the router bit of greater helical angle. However, when routing against the grain, the greater the helical angle the smoother was the machined surface. (3) There were correlations between the AE count rate and the machined surface roughness for each helical angle investigated. Therefore, acoustic emission has shown promise for monitoring and controlling the routing operation, including various grain angles and helical angles of the router bit.  相似文献   

14.
以自制白果粉为原料,分析了提取溶剂、粉料粒度、提取温度、超声波功率、料液比、提取时间及提取次数对白果出油率的影响。结果表明:石油醚(沸程60~90℃)是较适宜的提取溶剂,出油率为3.88%。最佳提取工艺为:白果粉粉碎度80目,提取温度25℃,超声波提取功率200 W,料液比1∶25(g/ml),每次提取时间40 min,提取次数2次。最优工艺条件下,出油率为3.86%,较索氏提取法,该工艺对白果粗脂肪的提取率为98.71%。  相似文献   

15.
Composition of neutral fractions in Chinese raw tall oil   总被引:1,自引:0,他引:1  
Chinese tall oil samples, obtained from pulp and papermaking factories in Qinzhou and Jiamusi of China, were first divided into acidic and neutral fractions by saponification, extraction, and distillation. The obtained neutral fractions were then analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) after silylation with bis-(trimethylsilyl) trifluoroacetamide. The results obtained show that 10 types of compound (monoterpenes, sesquiterpenes, diterpenes, triterpenes, resin alcohols, resin aldehydes, steroids, fatty alcohols, phenols, stilbenes) exist in the neutral fractions of Chinese raw tall oil. In the neutral fractions from Qinzhou, 55 components were identified, 35 of which were found for the first time in Chinese raw tall oil; 12 components were discovered for the first time in raw tall oil. In the neutral fraction from Jiamusi, 45 components were identified, 9 of which were discovered for the first time in Chinese raw tall oil.  相似文献   

16.
超临界 CO2 萃取落叶松木材挥发油的工艺研究   总被引:1,自引:0,他引:1  
采用超临界CO2萃取技术萃取落叶松木材挥发油,以得率为考察指标,研究了萃取压力、萃取温度、CO2流量和萃取时间对得率的影响.确定了超临界CO2萃取落叶松木材挥发油的最佳工艺参数:萃取压力35MPa,萃取温度60℃,CO2流量10kg/h,萃取时间2h,在此条件下挥发油得率可达0.57%.  相似文献   

17.
Prosopis cineraria is an important species for aridzone agroforestry in India. Information on the chemical composition and nutritive value of the leaves of young trees that will be useful in screening the provenances, is lacking. Chemical composition (N, P, K, Ca, Mg, Na), crude protein, and structural carbohydrates (neutral detergent fibre, acid detergent fibre, cellulose, hemicellulose, and lignin) of the foliage of one-year-old plants of 31 provenances ofProsopis cineraria were determined. The seeds were collected from 16°50 N to 29°55 N latitude and 69°49 E to 78°03 E longitude in India, and grown at Hisar (29°10 N latitude, 75°46 E longitude and 215 m altitude). Mineral contents (except N and P), crude protein, and structural carbohydrates varied significantly (p<0.05) between provenances, and the greatest amount of N, P, crude protein, NDF, ADF and lignin contents were found in Hisar provenance. The in vitro dry matter digestibility varied from 18.2% in Gandhinagar provenance to 34.0% in that of Barmer provenance.  相似文献   

18.
The different effects of heat treatment on wood, especially on the cellulose crystallites of wood under ovendried and highly moist conditions, were investigated by X-ray diffractometer. Heat was found to increase significantly the crystallinity of wood cellulose; moreover, almost twice as much crystallization was observed after heat treatment of spruce and buna under a highly moist condition than under the oven-dried condition. In pure cellulose almost the same crystallization was observed under both the conditions, whereas more crystallization occurred in wood cellulose than in pure cellulose. Absolute crystallization was observed for the wood species and pure cellulose under both conditions, considering the thermal decomposition of the amorphous region in addition to crystallization. Our results suggested that other components accomparying wood cellulose were involved in the increase of crystallinity by heat treatment, and that wood cellulose contained more quasicrystalline regions than pure cellulose. Moreover, calculated apparent activation energies revealed that crystallization and decrystallization in pure and wood cellulose under heat treatment of highly moist condition were some-what easier than those under the oven-dried condition. The behavior of the piezoelectric modulusd 25 almost paralleled that of crystallinity.  相似文献   

19.
Response surface methodology with central composite design was used to investigate the influence of pulping conditions, viz. cooking temperature, time-at-temperature and alkali charge for alkaline pulping of oil palm empty fruit bunch fibres, on the properties of the pulp and paper obtained (screened yield, Kappa number, tensile and tear indices). Quadratic models consisting of the three independent variables were found to accurately describe the pulping of this material with correlation between the actual and predicted values of the response variables having a relatively good degree of R2. The delignification of oil palm empty fruit bunch fibre can be achieved with ease using sodium hydroxide as the sole cooking agent to about 30–45% yield with the process greatly enhanced by an increase in temperature. Although, a relatively low temperature (about 160°C) within the limits of pulping time (60–120 min) and of alkali charge between 20 and 30% is generally sufficient.  相似文献   

20.
为探索闪式提取法提取樟树籽油的最佳工艺,选取对提取工艺影响较大的液料比、电压、提取时间3个因素,并在单因素试验的基础上,进行Box-Benhnken中心组合设计,利用响应面法对提取工艺进行优化。结果表明:闪式提取樟树籽油的最佳工艺条件为液料比12∶1、电压170 V、提取时间120 s,在最佳工艺条件下出油率为67.97%。认为闪式提取法可作为一种快速有效的樟树籽油提取方法。  相似文献   

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