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1.
The study was conducted to investigate some moisture-dependent physical properties of jatropha seed namely, seed dimension, 1000 seed mass, surface area, sphericity, bulk density, true density, angle of repose and static coefficient of friction against different materials. The physical properties of jatropha seed were evaluated as a function of moisture content in the range of 4.75–19.57% d.w. The average length, width, thickness and 1000 seed mass were 18.65 mm, 11.34 mm, 8.91 mm and 741.1 g, respectively at moisture content of 4.75% d.w. The geometric mean diameter and sphericity increased from 12.32 to 12.89 mm and 0.66 to 0.67 as moisture content increased from 4.75 to 19.57% d.w., respectively. In the same moisture range, densities of the rewetted jatropha seed decreased from 492 to 419 kg m−3, true density increased from 679 to 767 kg m−3, and the corresponding porosity increased from 27.54 to 45.37%. As the moisture content increased from 4.75 to 19.57% d.w., the angle of repose and surface area were found to increase from 28.15° to 39.95° and 476.78 to 521.99 mm2, respectively. The static coefficient of friction of jatropha seed increased linearly against the surfaces of three structural materials, namely plywood (44.12%), mild steel sheet (64.15%) and aluminum (68.63%) as the moisture content increased from 4.75 to 19.57% d.w.  相似文献   

2.
Moisture-dependent physical properties of niger (Guizotia abyssinica Cass.) seed were studied at 5.60, 12.99, 19.77, 27.08 and 31.65% moisture content (wet basis). The length, width, thickness and geometric mean diameter increased significantly (p < 0.05) from 3.86 to 4.06 mm, 0.96 to 1.02 mm, 0.86 to 0.96 mm and 1.47 to 1.59 mm, respectively with increase in moisture content from 5.60 to 31.65% whereas the increase in sphericity from 38.10 to 39.01% was not significant. Similarly, thousand seed mass, porosity and angle of repose increased (p < 0.05) linearly from 2.50 to 3.69 g, 41.76 to 47.65% and 29.86° to 39.12°, respectively with increase in moisture content under the experimental condition. The bulk density decreased significantly (p < 0.05) from 635.23 to 561.06 kg m?3 with increase in the moisture content range considered in the study, whereas the true density showed a slight increase from 1090.71 to 1098.42 kg m?3 with increase in moisture content from 5.60 to 27.08% followed by a drop from 1098.42 to 1071.75 kg m?3 as moisture content increased from 27.08 to 31.65%. Coefficient of static friction increased (p < 0.05) logarithmically from 0.34 to 0.51, 0.38 to 0.56 and 0.13 to 0.53 on mild steel, plywood and glass surfaces, respectively with increase in moisture content from 5.60 to 31.65%.  相似文献   

3.
The moisture-dependent physical properties are important to design post harvest equipments of the product. The physical properties of Karanja kernel were evaluated as a function of moisture content in the range of 8.56–22.22% d.b. The average length, width, thickness and 1000 kernel mass were 25.29 mm, 15.58 mm, 7.88 mm and 1036.45 g, respectively, at moisture content of 8.56% d.b. The geometric mean diameter and sphericity increased from 14.55 to 15.97 mm and 0.57 to 0.6 as moisture content increased from 8.56 to 22.22% d.b., respectively. In the same moisture range, the bulk density decreased from 663 to 616 kg/m3, whereas the corresponding true density and porosity increased from 967 to 1081 kg/m3 and 31.44 to 43.02%, respectively. As the moisture content increased from 8.56 to 22.22% d.b., the angle of repose and surface areas were found to increase from 27.69 to 37.33° and 665.74 to 801.63 mm2, respectively. The static coefficient of friction of Karanja kernel increased linearly against the surfaces of three structural materials, namely plywood (28.72%), mild steel sheet (29.88%) and aluminium (18.86%) as the moisture content increased from 8.56 to 22.22% d.b.  相似文献   

4.
A new series of petroselinic (Coriandrum sativum L.) based estolide 2-ethylhexyl (2-EH) esters were synthesized, as the capping material varied in length and in degrees of unsaturation, in a perchloric acid catalyzed one-pot process with the esterification process incorporated into an in situ second step to provide the coriander estolide 2-EH ester. The kinematic viscosities ranged from 53 to 75 cSt at 40 °C and 9.1 to 14.6 cSt at 100 °C with a viscosity index (VI) ranging from 151 to 165. The caprylic (C8) capped coriander estolide 2-EH ester had the lowest low-temperature properties (pour point = −33 °C and cloud point = −33 °C), while the coco-coriander estolide 2-EH ester produced an estolide with modest low-temperature properties (pour point = −24 °C and cloud point = −25 °C). The coco-coriander estolide 2-EH ester was explored for the ability to resist oxidative degradation with the use of an biodegradable additive package added in 1.5%, 3.5%, or 7.0% units based on weight. The oxidative stability increased as the amount of stability package increased (rotating pressurized vessel oxidation test (RPVOT) times 65-273 min). Along with expected good biodegradability, these coriander estolide 2-EH esters had acceptable properties that should provide a specialty niche in the U.S. as a biobased lubricant.  相似文献   

5.
土壤母质及其物理性状与茶叶品质关系   总被引:16,自引:1,他引:16  
曹顺爱  吕军 《茶叶》2003,29(1):13-16
本综述了我国茶园土壤母质类型及土壤容重、孔隙度、水分含量、团粒结构等物理性状对茶叶品质的影响,探讨了改善茶园土壤物理性状的措施,并提出今后茶园土壤物理性状所要研究的课题,这对我国无公害茶,有机茶的生产和发展具有一定意义。  相似文献   

6.
In this study, fire-retardant polyester fibers (FRPFs), which are hollow and have a 3D-crimp shape, were processed using nonwoven manufacturing technology to create fire-retardant fibrous material. The content of low-T m fibers (10, 20, 30, 40, 50 %) and number of layers of loose nonwoven sheet (1, 2, 3, 4, 5 layers) were changed to determine tensile strength and elongation, thermal conductivity, air permeability and the limiting oxygen index. The purposes of this study are to develop a manufacturing procedure for convenient installation of thermal insulation material and improve the application of fiber materials in thermal insulation. Experimental results demonstrate that, due to the loose nonwoven sheet combined with needle punching nonwoven sheets, tensile strength FRPFs increased to 100 %. The contents of the polyester low-melting-temperature fiber and the number of combined layers affected thermal conductivity results. In the test for the limit oxygen index, the optimal sample was manufactured using 7.78 dtex FRPFs, 10 % PET low-melting-temperature fiber and 5 layers of loose nonwoven sheet. The limit oxygen index is 35.  相似文献   

7.
Summary Achieving optimal colour and texture in French fries requires careful control of the unit operations that convert the raw potatoes into fries. The effects of variation in blanching, drying and finish frying conditions on puncture properties (peak force and peak deformation) and Hunterlab L (lightness) values of French fries were investigated. Fries blanched by low-temperature long-time (LTLT) conditions had larger peak force, peak deformation and L value than fries processed by standard conditions. High-temperature short-time (HTST) blanching increased lightness but decreased peak force and peak deformation. For drying, the colour and textural quality of French fries processed by standard conditions were better than those processed by the drying alternatives. For finish frying, LTLT conditions increased peak force whereas HTST conditions increased lightness. Therefore, a compromise has to be made in processing conditions to optimise both colour and textural quality. Even after finish frying, compositional differences within potato tubers influenced texture, both between and within French fries.  相似文献   

8.
Saturated mono-estolide methyl esters and enriched saturated mono-estolide 2-EH esters were synthesized from oleic and different saturated fatty acids under three different synthetic routes. Estolide numbers (EN), the average number of fatty acid units added to a base fatty acid, varied with synthetic conditions. The attempts at obtaining saturated mono-estolide 2-EH esters, EN = 1, via distillation proved to be challenging, which lead to estolide samples with EN > 1 and the pour point values followed the same trend as the high EN estolides. The other synthetic routes provided saturated mono-estolide methyl esters with EN = 1. The resulting pour point values showed a linear relationship between the saturated capping chain length and pour point. As the saturated capping chain length increased the pour points also increased (higher temperatures): C-2 capped ?30 °C, C-10 capped ?12 °C, and C-18 capped 3 °C.The saturated mono-estolide methyl ester viscosities also showed an increase in viscosity at 40 and 100 °C as the saturated chain lengths increased. The viscosities for the C-4 saturated mono-estolide methyl ester was 9.5 cSt at 40 °C and 2.6 cSt at 100 °C, while medium chain length derivations (C-10 saturated mono-estolide methyl ester) were 19.7 cSt at 40 °C and 4.2 cSt at 100 °C, and at the longer chain length derivations (C-18 mono-estolide methyl esters) were 27.6 cSt at 40 °C and 10.7 cSt at 100 °C. In general, a new series of saturated oleic mono-estolide methyl esters were synthesized and physical properties were collected. The physical property data indicated that both chain length and EN affect low temperature properties.  相似文献   

9.
About 15 Parthenium species grow in the North American continent with Parthenium argentatum (guayule) as the only species containing harvestable amounts of the rubber latex. The predicted commercialization of the guayule plant for its hypoallergenic latex will result in a significant amount of waste fiber or bagasse biomass that can also be put to use for making wood, paper, and other chemical products, as well as in energy production. Thus, the guayule wood and bark fibers can be considered a new source of plant biomass that may be used as a direct substitute for forest-based wood fiber. However, little information is available on the chemical composition of the wood and bark tissues of guayule (P. argentatum). The objectives of this study were to determine the chemical and fiber composition of guayule and to compare it with other wood fiber sources.Three germplasm lines of mature guayule (Cal-6, AZ-101, and G7-15) and another species of Parthenium (P. tomentosum, PT), juvenile soft maple (Acer rubrum), a deciduous tree, and milkweed (Asclepias syriaca L.) that has long fibers were the plant sources. Separate wood and bark tissues were analyzed for hot water, 1% sodium hydroxide, and alcohol–toluene extracts. In addition, the lignin, holocellulose, alpha-cellulose, and pentosan contents were determined.All the chemical components in the wood fibers for the Partheniums were equal to or greater than the juvenile maple tree. Milkweed had higher alpha-cellulose and lower alcohol–toluene extract contents than both the guayule and soft maple. The guayule bark fibers had more chemical extracts than the wood fibers. The specific gravity of guayule wood was greater than the deciduous wood species. However, the fiber lengths of soft maple wood, guayule wood, and milkweed are similar. Based on the chemical composition, P. argentatum and P. tomentosum could serve as raw materials for the paper and chemical industries as well as for energy production.  相似文献   

10.
A fabric drape shape database has been prepared to find the optimum combination of fabric physical properties for simulating the appearance of an actual fabric. First, an objective and quantitative evaluation method for the traditional Cusick drape tester has been devised. Then a virtual drape tester has been developed using an implicit integration based drape simulation engine to generate a series of virtually draped fabric with various physical properties. Finally, a search algorithm has been developed to find the optimum property combination for target fabric by comparing the simulated results with the Cusick drape tester result of that fabric.  相似文献   

11.
Glass woven fabric interlayered nonwovens composed of Nylon 6 staple fibers, recycled Kevlar fibers, and low-Tm polyester fibers are prepared into the glass-interlayer plank. Afterwards, their tensile strength, bursting strength, quasistatic and dynamic puncture resistances are evaluated by changing low-Tm polyester and Kevlar fibers mass fractions. The results show that when comprising 30 wt% of low-Tm polyester fibers and 20 wt% of Kevlar fibers, the composite plank yields the maximum tensile strength, bursting strength, quasi-static and dynamic puncture resistances. The double planks arranged in cross direction have higher quasi-static and dynamic puncture resistances than those oriented in parallel direction. According to stereoscope observations, the quasi-static and dynamic puncture resistances of glass-interlayer plank have different fracture mechanism for resisting against spike penetration. In addition, the bursting strength is proportional to quasistatic puncture resistance.  相似文献   

12.
During commercial sterilization of whole white potatoes, mild to severe breakage sometimes occurs. Physical properties of potatoes were measured before and after sterilization. These included major diameter, minor diameter, density, dry matter content, amylographic viscosity, compressive breaking strength, and tensile breaking strength. The experimental data were evaluated in terms of mean values from 33 different truckloads sampled at a commercial canning facility (60 tubers sampled per load). These properties were statistically compared to the incidence of breakage in sterilized potatoes. The results did not show significant relationships between any of the raw potato properties and the incidence of breakage. However, several properties of the sterilized potatoes (major diameter, peak viscosity, peak viscosity temperature) were linearly related to breakage (R2 = 0.84).  相似文献   

13.
100 % cotton light-weight plain knitted fabrics were treated with resin using different concentration by conventional pad-dry-cure method so as to influence their physical properties such as wrinkle-resistant, smoothness, dimensional properties and bursting strength. After resin treatment, the wrinkle-resistant property, smoothness and dimension stability of the four fabrics were consequently improved even after simulated domestic laundering process. The experimental results were reported and discussed thoroughly.  相似文献   

14.
Biodegradable foams made from potato starch and natural fibres were obtained by extrusion. The effects of varying origins of these fibres on foam properties were studied, as well the relationships between their properties and the foam microstructure. The addition of fibres increased the expansion index and led to a significant reduction in water adsorption of starch foams, generally improving foam properties. The mechanical properties of the foams were affected by both relative humidity (RH) of storage and foam formulation. In general, as the RH increased, the foam strength decreased. The formulation presenting the best mechanical properties contained 10 wt% hemp fibre and had a maximal resistance of 4.14 MPa and a modulus of 228 MPa, corresponding to a more compact and dense microstructure.  相似文献   

15.
The energy requirement for biomass comminution and the resulting particle physical properties are important factors to study logistic components, select equipment, and assess the overall efficiency of feedstock supply-conversion chain. In this study, mechanical size reduction of Miscanthus (Miscanthus giganteus), switchgrass (Panicum virgatum), willow (Salix babylonica), and energy cane (Saccharum spp.) was carried out using a commercial-scale hammer mill, a bench-scale Retsch SM2000 knife mill and a Retsch SK100 hammer mill. The results showed that the specific energy consumption of biomass comminution and the aperture sizes of the milling screens were related in power-law forms. Biomass moisture significantly influenced comminution energy consumption, especially for finer size reduction. Given a specific milling screen, the Retsch SK100 hammer mill was found more energy efficient than the SM2000 knife mill. This was mainly attributed to the higher motor speed and axial feeding mechanism of the hammer mill. The particle sizes after comminution were found inversely proportional to the bulk densities of all four energy crops used in experiments. In addition, the comminution ratio, being the ratio of the final mean particle size and the original mean particle size, was proportional to energy consumption for all four energy crops. The bulk densities for 4-mm and smaller Miscanthus and switchgrass particles were higher than those of the original bale. Particle size and surface area estimates using commonly used ANSI/ASAE Standards S424.1 and 319.4 were highly sensitive to particle size distributions and shapes. Further studies on standardization of particle size and surface area estimates are needed.  相似文献   

16.
The fresh ripe fruit pulp and syrup, produced using the open pan evaporator, ofVitex doniana were analysed physico-chemically. Results show that the edible pulp of the ripe fruit is fairly rich in vitamin C (18.1 mg/100 ml) but acidic (pH 4.38) and poor in protein (0.82%) and oil (0.56%). The syrup yielded a DE value of 52, total dissolved solids content of 67° Brix and a refractive index of 1.4762 at 20°C. The syrup was moderately visous (2.1 Poiseuille), acid (pH 4.45) but relatively poor in vitamin C (2.8 mg/100 ml) and protein (0.3%). Sensory evaluation showed no significant difference (p0.05) in taste, flavor and overall acceptability betweenV. doniana syrup and honey. Both physico-chemical and sensory results indicate that the syrup was highly desirable and can substitute for other syrups as a nutritive sweetener.  相似文献   

17.
18.
This research focused on the improvement of the physical properties of biopolyurethane (BPU) using cellulose nanowhisker (CNW). For the study, BPU was synthesized by one-shot polymerization from corn sugar-based polyol and methylene diiscocyanate (MDI). CNW was prepared via conventional acid hydrolysis of pulp using sulfuric acid. The synthesized BPU was mixed with the CNW and then electrospun. The addition of CNW improved simultaneously the hydrophilicity and the mechanical properties of BPU. The improved properties will give more opportunity to BPU for medical applications.  相似文献   

19.
For nearly half a century textile prostheses have been intensively used in vascular surgery. They have saved millions of human lives, but they are not yet perfect. Graft failures have been, in part, attributed to the prostheses finishing processes, generally based on thermal treatments. These treatments permit to reduce fabric porosity and fix the wavy form of prosthetic tube walls involved by crimping process. Four tubular fabrics have been woven with different polyethylene terephthalate (PET) yarns spun under different industrial processes: Setila, Dacron, Diolen and Viscosuisse. Three heat setting techniques were investigated for prostheses crimping: dry heat, vapor heat and autoclaving. Crystallinity index and crystal growth in the equatorial directions have been calculated from Wide Angle X-ray Scattering scans. The aim was to analyze physical structural changes of PET fibers after thermal finishing processes applied to textile vascular prostheses and highlight fiber morphological evolutions related to these treatments. Viscosuisse yarns held the largest crystalline domains built up of numerous crystals but smaller than Dacron ones. However, the best crystalline configurations for the overall yarns were generally obtained for dry heat processes. Compromise regions of treatment conditions for prosthetic Dacron tubes were also obtained to optimize crystal development for the different crimping processes.  相似文献   

20.
鄂东(北)茶园土壤物理环境分析   总被引:3,自引:0,他引:3  
胡学玉  张继铭  江洪  杨利  余昭齐 《茶叶》2004,30(3):150-152
采用土壤调查的方法,分析了鄂东(北)茶园土壤硬度、土壤耕层厚度、土壤容重及土壤三相(固相、液相、气相)容积比等物理性状,探讨了土壤物理环境对茶叶品质的影响。  相似文献   

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