Transit funding: Implications of federal aid strategies

Federal funding strategies greatly affect investment in urban transportation facilities in the United States. This analysis concentrates on the implications of varying federal aid matching requirements, structuring aid programs as categorical or block grants, and allo cating funds on a discretionary basis or according to formula. Toward this end the effects of recent federal transit aid arrangements are assessed.Increased federal matching share broadens program participation, especially among smaller cities. However, when offered a choice, communities' preference for more generous federal aid shares is tempered by their election of discretionary grants (e.g., Urban Mass Transportation Administration - UMTA - Section 3) instead of drawing on formula funds (e.g., UMTA Section 5 or highway fund transfers). Formula funds are easier to administer, distributed quite evenly in the UMTA case, and generally more suitable than discretionary funds except where expenditures are large relative to budgets. Categorical aid programs shift local priorities, and thus should be used with cautionOverall, results suggest that one must begin with established transportation objectives against which to evaluate the effectiveness of funding arrangements. In particular, it is critical to make clear the rationale for federal involvement in funding specific programs. Four such federal funding intents are distinguished: compelling national interest, regional development, stimulation of recipient investment in the given program, or financial relief for the aid recipient. Conclusions are drawn as to the desirability of various funding policies according to such program intent.     

The role of subsidy policies in modernizing the structure of the bus transit industry

Full reliance on conventional forms of bus transit for peak hour needs reduces industry productivity and creates major new subsidy requirements. Restructuring of transit is needed to enable paratransit integration and other innovations than can improve efficiency. This paper discusses the industry's long-term neglect of efficiency and describes subsidy policies that would promote necessary changes.     

临海复杂地质条件下深基坑围护设计和施工技术

通过对地下室深基坑围护的设计方案论证,采用旋喷止水帷幕结合自然放坡和明沟排水的方案成功解决了临海复杂地质条件下深基坑围护施工的问题。     

A Method to Analyse the Dynamic Behavior of a Motorcycle Front Suspension Equipped with Sequential Dampers

This work analyses the dynamic behavior of a motorcycle front suspension equipped with passive sequential hydraulic dampers, in some operative situations. The dampers, with non-linear and asymmetric characteristics, may be regulated in six different ways. Using experimental elasticity and damping data as reference parameters, and a simplified two-degrees-of-freedom model, some dynamic simulations were carried out in order to define damping parameters for optimal comfort and safety.     

Glacial–interglacial changes in the accumulation rates of major biogenic components in Southern Indian Ocean sediments

In this study we compare major biogenic components (opal-A, carbonate, and organic carbon) and authigenic uranium accumulation rates from the southeastern Indian Ocean for both Holocene and glacial periods. Integrated accumulation rates across the whole Indian sector of the Southern Ocean indicate that the burial of organic carbon which is held approximately constant, contrasts with lower biogenic silica and carbonate burial rates during glacial intervals. In addition, higher glacial accumulation rates of authigenic uranium are found in the sediments of the Polar Front Zone (PFZ) and the Sub-Antarctic zone (SAZ) than anywhere in the modern Southern Ocean. This suggests more reducing conditions in the PFZ and SAZ during the last glacial maximum. The simplest explanation of a northward shift of the PFZ cannot explain such changes. Glacial sediment burial changes result probably from deep water decrease in oxygen levels and increase in CO₂ due to combination of two processes: (1) hydrologic changes and (2) continuous organic carbon export fluxes to the seafloor. Such shifts in chemical conditions could have enhanced the dissolution of carbonates and better preserved the organic carbon in sediments, leading in significant changes of biogenic silica/C_org and CaCO₃/C_org flux ratios.     

Estimating salinity to complement observed temperature: 2.Northwestern Atlantic

This paper addresses the problem of estimating salinity for a large region in the Atlantic Ocean containing the Gulf Stream and its recirculation. Together with Part 1 [Thacker, W.C., 2007-this issue. Estimating salinity to complement observed temperature: 1. Gulf of Mexico. Journal of Marine Systems. doi:10.1016/j.jmarsys.2005.06.008.] dealing with the Gulf of Mexico, this reports on the first efforts of a project for developing world-wide capability for estimating salinity to complement expendable-bathythermograph (XBT) data. Such estimates are particularly important for this region, where the strong frontal contrasts render the task of assimilating XBT data into numerical models more sensitive to the treatment of salinity.Differences in salinity's co-variability with temperature and with longitude, latitude, and day-of-year from the northwestern part of the region with the Gulf Stream to the southeastern part more characteristic of the Sargasso sea suggested that the region be partitioned to achieve more accurate salinity estimates. In general, accuracies were better in the southeastern sub-region than in the more highly variable northwestern sub-region with root-mean-square estimation errors of 0.15 psu at 25 dbar and 0.02 psu at 300 dbar as compared with 0.35 psu and 0.50 psu, respectively, but in the southeast there was an unexpected error maximum around 1000 dbar where estimates were slightly less accurate than in the northwest. For pressures greater than 1400 dbar root-mean-square errors in both sub-regions were less than 0.02 psu.     

X4K型集装箱专用平车的研制

介绍了X4K型集装箱专用平车的研制概况、主要技术参数、结构及试验情况。     

Assessment of sea surface temperature observational networks in the Baltic Sea and North Sea

The satellite and in situ Sea Surface Temperature (SST) observational networks in the Baltic Sea and North Sea are evaluated based on the quality of the gridded SST products generated from the networks. A multi-indicator approach is applied in the assessment. It includes evaluation of data quality, effective data coverage, field reconstruction error and model nowcast error. The results show that the best available full-coverage SST product is generated by assimilating the SST observations to obtain a yearly mean model bias of 0.07 °C and RMSE of 0.64 °C. The effective data coverage rate is 31% by using AVHRR (Advanced Very High Resolution Radiometer) data from NOAA (National Ocean and Atmosphere Administration) satellites 12, 14 and 16. The data redundancy increases rapidly with the number of infrared sensors. Using either NOAA satellite 12 or all 3 satellites makes a small difference with regard to derived effective coverage and the ocean model nowcast error. The influence of using the in situ SST observations in the SST field reconstruction is negligibly small. Instead, the major role of in situ SST observations is in calibrating the satellite observations. To study the relative importance of data quality and data coverage, an assessment is done for two satellite products: one product is based entirely on NOAA 12 data and has larger coverage but lower quality. The other product is a subset of the SAF products (derived from NOAA 14 and 16) and has lower coverage but higher quality. Based on current monitoring, modelling and assimilation technology, the results suggest that the data quality is an important factor in further improving the quality of the gridded SST products. Recommendations are made for possible further improvements of the existing SST observational networks.