简化Navier-Stokes(SNS)方程在二维层流边界层分离点邻域的特性

文中证明了本文第二作者提出的简化Navier-Stokes(SNS)方程在层流边界层分离点数学上为正则.Davis和Голвачев-Куэьмин-Попов 提出的SNS方程在分离点为数学奇异.进而论证了文献[2,3]的SNS方程在层流边界层分离点的奇异阶.最后给出了Navier-Stokes方程、上述两种SNS方程以及边界层方程在分离点邻域特性的比较.

Character of simplified Navier-Stokes (SNS) equations near separation point for two-dimensional laminar flow over a flat plate

It is proved that the simplified Navier-Stokes (SNS) equations presented by Gao Zhi[1], Davis and Golowachof-Kuzbmin-Popof (GKP)[3] are respectively regular and singular near a separation point for a two-dimensional laminar flow over a flat plate. The order of the algebraic singularity of Davis and GKP equation[2,3] near the separation point is indicated. A comparison among the classical boundary layer (CBL) equations, Davis and GKP equations, Gao Zhi equations and the complete Navier-Stokes (NS) equations near the separation point is given.

Flood of September 20-23, 1969 in the Gadsden County area, Florida

The center of low pressure of a tropical disturbance which moved northward in the Gulf of Mexico, reached land between Panama City and Port St. Joe, Florida, on September 20, 1969. This system was nearly stationary for 48 hours producing heavy rainfall in the Quincy-Havana area, 70-80 miles northeast of the center. Rainfall associated with the tropical disturbance exceeded 20 inches over a part of Gadsden County, Florida, during September 20 through 23, 1969, and the maximum rainfall of record occurred at Quincy with 10.87 inches during a 6-hour period on September 21. The 48-hour maximum of 17.71 inches exceeded the 1 in 100-year probability of 16 inches for a 7-day period. The previous maximum rainfall of record at Quincy (more than 12 inches) was on September 14-15, 1924. The characteristics of this historical storm were similar in path and effect to the September 1969 tropical disturbance. Peak runoff from a 1.4-square mile area near Midway, Florida, was 1,540 cfs (cubic feet per second) per square mile. A peak discharge of 45,600 cfs on September 22 at the gaging station on the Little River near Quincy exceeded the previous peak of 25,400 cfs which occurred on December 4, 1964. The peak discharge of 89,400 cfs at Ochlockonee River near Bloxham exceeded the April 1948 peak of 50,200 cfs, which was the previous maximum of record, by 1.8 times. Many flood-measurement sites had peak discharges in excess of that of a 50-year flood. Nearly $200,000 was spent on emergency repairs to roads. An additional $520,000 in contractual work was required to replace four bridges that were destroyed. Agricultural losses were estimated at $1,000,000. (44 page document)

Assessing Biological Control Damage of Giant Salvinia with Field Reflectance Measurements and Aerial Photography

A study was conducted on a small pond in southeast Texas to evaluate the potential for using remote sensing technology to assess feeding damage on giant salvinia ( Salvinia molesta Mitchell) by the salvinia weevil ( Cyrtobagous salviniae Calder and Sands). Field spectral measurements showed that moderately damaged and severely damaged plants had lower visible and near-infrared reflectance values than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be differentiated in an aerial color-infrared photograph of the study site. Computer analysis of the photograph showed that the three damage level classes could be quantified. (PDF has 5 pages.)

Remote sensing of giant salvinia in Texas waterways

Giant salvinia (Salvinia molesta Mitchell) is an invasive aquatic fern that has been discovered at several locations in southeast Texas. Field reflectance measurements were made on two classes of giant salvinia [green giant salvinia (green foliage) and senesced giant salvinia (mixture of green and brown foliage)] and several associated species. Reflectance measurements showed that green giant salvinia could be best distinguished at the visible green wavelength, whereas senesced giant salvinia could generally be best separated at the near-infrared (NIR) wavelength. Green giant salvinia and senesced giant salvinia could be detected on color-infrared (CIR) aerial photographs where them had pink and grayish-pink or olive-green image responses, respectively. Both classes of giant salvinia could be distinguished in reflectance measurements made on multiple dates and at several locations in southeast Texas. Likewise, they could he detected in CIR photographs obtained on several dates and at widely separated locations. Computer analysis of a CIR photographic transparency showed that green giant salvinia and senesced giant salvinia populations could he quantified. An accuracy assessment performed on the classified image showed an overall accuracy of 87.0%.

Seasonal Changes in Chemical Composition of Eurasion Watermilfoil (Myriophyllum spicatum L.) and Water Temperature at Two Sites in northern California: implications for Herbivory

We compared seasonal changes in Eurasian watermilfoil (Myriophyllum spicatum L.) characteristics and water temperature for a shallow poind in Davis, CA, and the Truckee River, near Tahoe City, CA. Tissue C and N were 15% lower in plants from the Truckee River than in plants from the Davis pond. Seasonal fluctuations in tissue N were also different. Mean phenolic acid content of Truckee River palnts (162yM g-1) was less than those from the shallow pond (195 yM g-1). Phenolic acid content was positively related to tissue C for Truckee River and Davis pond plants and, tissue C:N ratio for Truckee River plants. Mean monthly water temperature (1990 to 1998) for the Truckee River site was less than 20 C. Water temperatures were warmer in August and September at this site. However, Eurasian watermilfoil collected during these months was characterized by lower levels of tissue N. During a 29-month period beginning January 1994, mean monthly water temperature for the Davis pond exceeded 20 C, only during July to September 1995. Tissue N was generally greater during summer for watermilfoil growing in the pond. These results imply that Eurasian watermilfoil biological control agents may have different developmental rates in these habitats, and thus different impacts on watermilfoil populations.

Using Remote Sensing and Spatial Information Technologies to Detect and Map Two Aquatic Macrophytes

This paper describes the light reflectance characteristics ofwaterhyacinth [Eichhornia crassipes (Mort.) Solms] and hydrilla [Hydrilla verticillata (L.F.) Royle] and the application of airborned videography with global positioning system (GPS) and geographic information system (GIS) technologies for distinguishing and mapping the distribution of these two aquatic weeds in waterways of southern Texas. Field reflectance measurements made at several locations showed that waterhyacinth generally had higher near-infrared (NIR) reflectance than associated plant species and water. Hydrilla had lower NIR reflectance than associated plant species and higher NIR reflectance than water. Reflectance measurements made on hydrilla plants submerged below the water surface had similar spectral characteristics to water. Waterhyacinth and hydrilla could be distinguished in color-infrared (CIR) video imagery where they had bright orange-red and reddish-brown image responses, respectively. Computer analysis of the imagery showed that waterhyacinth and hydrilla infestaions could be quantified. An accuracy assessment performed on the classified image showed an overall accuracy of 87.7%. Integration of the GPS with the video imagery permitted latitude/longitude coordinates of waterhyacinth and hydrilla infestation to be recorded on each image. A portion of the Rio Grande River in extreme southern Texas was flown with the video system to detect waterhyacinth and hydrilla infestaions. The GPS coordinates on the CIR video scenes depicting waterhyacinth and hydrilla infestations were entered into a GIS to map the distribution of these two noxious weeds in the Rio Grande River.

The distribution of cirripeds and gastropods on plain vertical rock surfaces in the upper intertidal and splash zones

This is a student paper done for a University of California Berkeley Zoology class. Since UCB didn't have its own marine lab at the time, it rented space at Hopkins Marine Station where this work was done. Cadet Hand earned his Ph.D. from Berkeley and went on to become Director of the Bodega Marine Laboratory. Donald Putnam Abbott also earned his Ph.D. from Berkeley and later became a Stanford professor at Hopkins Marine Station. (PDF contains 26 pages)

Notices of Brazil in 1828 and 1929

Contém notas detalhadas da viagem do sacerdote inglês, em meados do Século XIX, às Províncias do Rio de Janeiro e de Minas Gerais, com especial atenção aos fenômenos sociais, enfatizando a situação dos escravos no Brasil, seu tráfico desde o descobrimento até a coroação de D.Pedro I. Reproduz, no apêndice do volume 2, documentos históricos e a partitura do Hino Imperial, composto por D. Pedro I, conforme anotações de Borba de Moraes.

Reducing non-point DOC and nitrogen exports from rice fields: A pilot study and quantitative survey to determine the effects of different hydrologic management practices : Deliverable 15.3 Final Report

Rice cultivation at any level in the Sacramento–San Joaquin Delta (existing or expanded) compels the need to quantify surface and subsurface loads of dissolved organic carbon (DOC), disinfection byproduct precursors (DBPPs) and nitrogen. This information can be used to develop Best Management Practices (BMPs) to reduce export of these constituents in order to improve drinking water quality. Although rice cultivation in the Delta is relatively limited, several factors outside of this research could contribute to increased rice acreage in the Delta: • Recently developed rice varieties seem more suitable for the Delta climate than earlier varieties which required warmer conditions; • Previous economic analyses (Appendix A.10) suggest rice is more profitable than corn, a dominant land use in the Delta; • Recent studies on wetlands at Twitchell Island suggest rice production can help mitigate oxidative subsidence (Miller et al. 2000); • The different oxidative states that result from flooding in rice as compared to those found in crops that require drained soils may help control crop specific weeds and nematodes when rice is incorporated into a crop rotation; and • Providing flooded conditions during a greater part of the year than other crops may benefit water birds. ... (PDF contains 249 pages)

Preliminary guide to the indentification of the early life history stages of Callionymid fishes of the Western Central Atlantic

Callionymidae, along with the Draconettidae and Gobiesocidae, previously were placed in the order Gobiesociformes (Allen, 1984). Recently, Nelson (1994) placed the Callionymidae and Draconettidae in the percifonn suborder Callionymoidei. The family is represented by three species in the western central North Atlantic Ocean, Diplogrammus pauciradiatus, Paradiplogrammus bairdi and Foetorepus agassizi (Davis, 1966; Robins and Ray, 1986). A detailed review ofthe family including early life history infonnation is given by Houde (1984) and Watson (1996). (PDF contains 11 pages)

Salieri Speaks: Peter Shaffer's two version of Amadeus

Eguíluz, Federico; Merino, Raquel; Olsen, Vickie; Pajares, Eterio; Santamaría, José Miguel (eds.)