非饱和土壤物理特性数据处理软件APPIA的数理基础分析

APPIA是用于非饱和土壤物理特性数据处理的专用软件,可快速分析非饱和土壤持水曲线和导水曲线并给出相关参数.系统分析了APPIA的数理基础,并对不同方法分析的结果进行了比较.结果表明:用APPIA程序可获得较为准确的非饱和土壤物理参数,应广泛推广使用.     

非饱和土壤物理特性数据处理软件APPIA的数理基础分析

ＡＰＰＩＡ是用于非饱和土壤物理特性数据处理的专用软件,可快速分析非饱和土壤持水曲线和导水曲线并给出相关参数。系统分析了ＡＰＰＩＡ的数理基础,并对不同方法分析的结果进行了比较。结果表明：用ＡＰＰＩＡ程序可获得较为准确的非饱和土壤物理参数,应广泛推广使用。     

Physical Properties of Vetch Seed

The physical properties of vetch seed were evaluated as a function of moisture content. The average length, width and thickness were 5·19, 4·33 and 3·63 mm, respectively, at 10·57% dry basis (d.b.) moisture content. In the moisture range from 10·57 to 20·63% d.b., studies on rewetted vetch seed showed that the thousand seed mass increased from 55·47 to 59·03 g, the projected area from 23·52 to 29·05 mm², the sphericity from 0·837 to 0·859, the true density from 1286·2 to 1369·9 kg m⁻³, the porosity from 33·08% to 39·68% and the terminal velocity from 9·94 to 10·33 m s⁻¹. The static coefficient of friction of vetch seed increased the linearly against surfaces of four structural materials, namely, rubber (0·350–0·387), aluminium (0·319–0·367), stainless steel (0·202–0·328) and galvanised iron (0·312–0·361) as the moisture content increased from 10·57 to 20·63% d.b. The bulk density and the shelling resistance decreased from 860·8 to 826·2 kg m⁻³ and from 148·73 to 62·68 N, respectively, with an increase in moisture content from 10·57 to 20·63% d.b.     

聚丙烯酰胺对土壤物理性质的影响

以不同剂型、不同浓度对土壤施入聚丙烯酸胺,探讨其对土壤物理性质的影响,试验结果表明:土壤经聚丙烯酸胺处理后一般沉降系数增大9%,分散系数减少7%～及9%,结构系数增大3%～8%,水稳性团粒含量增加30%～50%,结构性能增强3%～8%,土壤渗透性能增大32%。这些指标证明该材料是较好的土壤结构改良剂之一,对防治土壤侵蚀起重要作用。     

Physical properties of soils in Rostov agglomeration

Physical properties of natural and anthropogenically transformed soils of Rostov agglomeration were examined. The data obtained by conventional methods and new approaches to the study of soil physical properties (in particular, tomographic study of soil monoliths) were used for comparing the soils of different functional zones of the urban area. For urban territories in the steppe zone, a comparison of humus-accumulative horizons (А, Asod, Ap, and buried [A] horizons) made it possible to trace tendencies of changes in surface soils under different anthropogenic impacts and in the buried and sealed soils. The microtomographic study demonstrated differences in the bulk density and aggregation of urban soils from different functional zones. The A horizon in the forest-park zone is characterized by good aggregation and high porosity, whereas buried humus-accumulative horizons of anthropogenically transformed soils are characterized by poor aggregation and low porosity. The traditional parameters of soil structure and texture also proved to be informative for the identification of urban pedogenesis.     

Physical and Molecular Characterization of Millet Starches

This study investigated the physical and molecular starch characteristics of four Canadian‐grown millet species: pearl, foxtail, proso, and finger millet. The millet starch granules ranged from about 2.5 to 24 μm in size and were mainly polygonal with a few spherical ones. Their amylose contents ranged from 28.6 to 33.9%, with finger and pearl millets having much more of long amylose chains than short amylose chains compared with foxtail and proso millets. Starches also differed in the molecular structure of their branched amylose, with finger and pearl millets having longer glucan chains between branch points. The enthalpy of gelatinization of starch granules ranged from 11.8 to 13.2 J/g, and the enthalpy of melting of the retrograded starches ranged from 2.2 to 5.9 J/g. The onset temperature of gelatinization (T_o) of the starches ranged from 62.8 to 70.6°C. Addition of iodine vapor to the granular starches showed significant (P < 0.05) differences in the ratio of the absorbance to scattering coefficient (K/S) values, indicating differences in the rigidity of the glucan chains present in the granules. Starches with short amylose chains exhibited higher K/S values. Iodine vapor addition resulted in altered X‐ray diffractogram peak intensities. The study suggested differences in the structure and granular architecture of the millet starches.     

Physical Properties of Raw and Parboiled Paddy

The physical properties namely, size and shape, bulk density, true density, and angle of repose at moisture contents ranging from 7·19 to 28·28% d.b. for raw paddy (IR-36) and from 12·24 to 43·53% d.b. for parboiled paddy were determined using standard techniques. In the case of raw paddy, the thousand grain weight increased from 23·04 to 27·16 g with an increase in moisture content from 10·45 to 32·13% d.b. Bulk density and angle of repose increased from 522 to 566 kg/m³ and 42·35 to 49·30°, respectively, with an increase in moisture content from 7·19 to 27·86% d.b. True density and porosity decreased from 1405 to 1348 kg/m³ and from 62·84 to 58·01% respectively, with an increase in moisture content from 7·19 to 27·86% (d.b.). In the case of parboiled paddy, bulk density and angle of repose increased from 507 to 564·8 kg/m³ and 39·90 to 43·89°, respectively, with an increase in moisture content from 12·24 to 43·53% d.b. True density and porosity decreased from 1411 to 1342 kg/m³ and from 64·08 to 57·91% respectively, with an increase in moisture content from 12·24 to 43·53%. The physical properties were linearly dependent upon moisture content.     

Physical Properties of Extruded Wheat Starch-Additive Mixtures

The effects of the addition of fatty acids, monoglycerides (MG), and wheat germ oil (WGO) on the level of crystallinity and the crystalline structure of extrusion-cooked wheat starch have been studied using twin-screw extruders. Measurements of water solubility and water absorption indices were made on the extrudates, together with specific mechanical energy (SME) consumption and die pressure for the extruder. MG and the fatty acids added to a level of 4% caused an increase in V_hydrate type crystallinity. WGO addition to a level of 8% caused no change in crystallinity, although the E_hydrate type was favored at lower moisture contents. All additives caused a decrease in SME and an increase or maximum in die pressure. WGO behaved differently than MG and fatty acids in that its addition caused the water solubility index and expansion to increase, as previously observed for other oils added to flours.     

Thermodynamic Concept of the Physical Quality of Soils

Eurasian Soil Science - Soil physical quality is largely determined by interphase interactions at variable moisture content. This phenomenon allows us to consider the water retention curves as...     

Physical Properties of Composted Materials Mixed with Sand

? The end product from the Portage, Wisconsin cocomposting facility is a loose, dark brown, organic material containing small fragments of glass, rubber, metal, plastics, and other materials that are resistant to decomposition. A research program was completed to determine the suitability of the compost for use in highway embankments or other engineered fills. Standard Proctor tests were conducted to determine the maximum density and optimum water content of the compost-sand mixtures. Direct shear tests were conducted on specimens compacted at maximum density and optimum water content. The cocomposted material mixed with sand proved to have sufficient shear strength for use in embankment construction.     

几种栽培花卉基质的理化特性研究

对几种重要的花卉栽培基质的理化性质进行了测定,结果表明:岩棉的通透性能很好,几乎不含有效养分、无缓冲能力。泥炭本身含有一定的养分,大小孔隙度、容重适度,总盐含量适中,有一定的缓冲能力。椰糠的总盐含量和水溶性盐含量过高,在使用前必须进行处理。泥炭、椰糠采用混合基质后,理化性质有所改善。蛭石:珍珠岩(V:V=1:1)的保水力相对较差。在生产中,除考虑基质的上述理化性质即实用性外,还必须根据经济性的原则考虑基质的选择。     

牡丹花红色素理化性质研究

目前牡丹主要是用于观赏,其综合加工技术没有突破。为了为牡丹花保鲜、护色和色素加工提供理论支持,该文对从牡丹红色品种洛阳红中提取的牡丹红色素进行理化性质研究。结果显示:牡丹红色素水溶性好,颜色随pH值变化而变化。pH值小于3时比较稳定,最大吸收波长为526.5 nm。在酸性条件下该色素对光、热有很好的稳定性;耐氧化性和还原性较差;Zn²⁺、Mg²⁺、Fe²⁺、K⁺、Cu²⁺、Ca²⁺离子对牡丹花红色素的稳定性影响不大,但Sn²⁺、Fe³⁺离子可使色素溶液变色,稳定性差。     

不同作物秸秆加工制成生物质炭的理化性质比较研究

为表征不同作物秸秆加工制成的生物质炭的理化性质差异,以玉米、水稻和油菜的秸秆为原料制备生物质炭,借鉴材料科学的方法,研究其形貌结构、表面特性和有机组分元素比等内容。结果表明:200℃→450℃作物秸秆样品失重量和失重速率最大,半纤维素和纤维素为主要燃失物质。玉米、水稻和油菜的秸秆生物质炭均为多孔结构,孔隙大小和形状各异。水稻秸秆炭的比表面积最大(2.65 m2g-1)、油菜秸秆炭次之(2.56 m2g-1)、玉米秸秆炭最小(1.84 m2g-1)。水稻、玉米、油菜秸秆炭的孔体积变化率分别在43 nm、62 nm、48 nm处达到峰值。油菜秸秆炭的H/C最小、为0.03,O/C和(O+N)/C最大、分别为1.15和1.19。因此,450℃更利于残留样品质量;生物质炭的孔隙结构决定其比表面积,油菜秸秆炭具有更强的芳香性、亲水性和极性。研究结果可为生物质炭的制取和应用提供参考依据。     

RELS的性质和几个物理定律

论述了RELS的几个常数以及它的特性,总结了RELS系统中有三个特性即连续性。调节性和和谐性。把能量中的几个物理定律同降雨、坡面径流联系起来,为进一步研究水上流失提供了理论基础。     

猪粪物理特性的测定

猪粪的物理特性对于猪粪处理是非常重要的因素,文中对猪粪的物理特性包括粒度分布、比重、容重、酸度、粘度、含水率和沉降性能等的测试结果进行了介绍。为处理和利用猪粪提供了基础数据。     

猪粪物理特性的测定

猪粪的物理特性对于猪粪处理是非常重要的因素,文中对猪粪的物理特性包括粒度分布、比重、容重、酸度、粘度、含水率和沉降性能等的测试结果进行了介绍。为处理和利用猪粪提供了基础数据。