Nitrogen budget for fescue pastures fertilized with broiler litter in Major Land Resource Areas of the southeastern US

The southeast US produces a tremendous number of broiler chickens (Gallus gallus), which in turn produce massive quantities of litter (manure and bedding materials). In the Southeast, litter is most often disposed of via land application to pastures, however, the ultimate fate of much of the applied nitrogen (N) is not known. We have constructed N budgets for three sites across the southeastern U.S. in an effort to determine how much of the applied N is useful for plant production and how much is left to be absorbed by the environment. Study sites were located in the Coastal Plain (Alabama), Piedmont (Georgia), and Cumberland Plateau (Tennessee) Major Land Resource Areas (MLRA) of the southeastern US. Litter was applied in the Spring of two consecutive years at a rate to supply 70 kg of available N ha^–1. The total amount of N applied ranged from 103 to 252 kg N ha^–1 depending on site and year. Nitrogen fluxes monitored in this study were broiler litter N, ammonia (NH₃) volatilization, denitrification, plant uptake, and leaching. Plant uptake represented the largest flux of applied N, averaging 43% of applied N. Losses due to NH₃ volatilization and denitrification combined were only 6% of applied N on average. Loss of N due to NO₃-N leaching appeared to be significant only at the Coastal Plain site where NO₃-N concentrations in the groundwater peaked at 38 mg N l^–1. We believe the majority of excess N shown in these budgets is likely accounted for by leaching losses and soil accumulation. Regardless of these assumptions and low gaseous losses, it is apparent that on average, 57% of applied N is destined for a fate other than plant uptake. The results of this study indicate that land-application of broiler litter at currently recommended rates has the potential for negative impacts on the environment of the southeastern U.S. in the long-term.     

Influence of organic and colloidal fouling on the removal of sulphamethoxazole by nanofiltration membranes.

This study investigated the effects of organic and colloidal fouling on the removal of a representative micropollutant sulphamethoxazole by two commercially available NF membranes. Alginate, bovine serum albumin and colloidal silica were selected as model foulants to simulate hydrophilic and hydrophobic organic fractions, and colloidal matter that are often found in treated effluent and surface water. Membrane fouling was related to the membrane and foulant characteristics and subsequently the separation behaviour of the micropollutant sulphamethoxazole under different solution pH. On the basis of these results, it was confirmed that membrane fouling is strongly dependent on both the foulant and membrane characteristics. The complex relationship among retention mechanisms, fouling mechanisms and the effects of fouling on retention was systematically delineated. Of the three model foulants selected for this study, colloidal fouling resulted in the most significant reduction in retention of sulphamethoxazole as well as inorganic salts, while flux decline as a result of colloidal fouling was quite moderate. Reduction in retention caused by fouling was attributed to a phenomenon known as cake-enhance concentration polarisation, which was a predominant mechanism of colloidal fouling. In addition, the reported results suggested that the effect of fouling on retention is also membrane pore size dependent.     

The electron storage ring as a source of infrared radiation

The characteristics of synchrotron radiation in the infrared region have been investigated at the Berlin electron storage ring BESSY using Fourier spectroscopy. In accordance with calculation, it was found that BESSY at 100 mA beam current delivers higher fluxes than a conventional source only in the spectral region below 30 cm^?1, provided the interferometer is the throughput-limiting element. If, however, the throughput is limited by small sample size or, if the experiment requires a large f-number, the high brightness of synchrotron radiation could already yield flux advantages at several hundred wavenumbers. The possible application in one particular experiment - infrared reflection-absorption spectroscopy of adsorbed molecules on metal single crystal surfaces - is discussed. In the course of the investigations described here, it was also established that the short light pulses of the synchrotron radiation (～ 100 ps) do not adversely affect the resolution in Fourier transform spectroscopy.     

Measurement of the mixing quality in premix combustors

The problem of mixing fuel and air is the essential point of low emission combustion in gas turbines. In premixed combustors and fuel staged combustors the quality of the fuel–air mixture is the determinant parameter for the amount of emissions of nitric oxides (NO_x). The nearly perfect preparation of the fuel–air mixture is also a condition for trouble-free operation in catalytical combustion. Prevaporization of liquid fuels hampers the process of mixing. So the investigative work at the Department of Steam and Gas Turbines at the University of Bochum concentrated on experiments with liquid fuels. The results show that there is a great potential of reducing NO_x emission even with liquid fuels and reveal the key role of prevaporization and mixing. The experiments were carried out at a premix combustion test rig at moderate pressure. By using the technique of planar-laser induced fluorescence (LIF), highly time and spatially resolved measurements of fuel concentrations were yielded from the experiments. The optical measurements showed the structure of the mixture field of fuel and air in the zone downstream of the flameholder. The pollutant emissions were simultaneously monitored with conventional gas analysers. As the main result, the strong dependence of the pollutant emissions on the mixture could be clearly revealed. On one hand the homogeneity over the cross-section of the combustor was the main condition for low emission combustion. On the other hand the time-resolved two-dimensional LIF images of the turbulent mixture field showed that the instationary distribution also had a considerable influence on the rate of emissions. Even the mixture of static mixers contained spatial and temporal inhomogeneities, which could be observed by using the LIF-technique but not with conventional methods.     

Nonlinear effects in coherent multichannel transmission throughoptical fibers

Various nonlinear optical interactions in single-mode fibers that are used in coherent FDM (frequency division multiplexed) transmission systems are examined. It is these nonlinearities that lead to crosstalk between channels, power losses, and deleterious fluctuations, which in turn limit the power of the transmitted light and the number of allowed channels, and dictate the channel allocations. It is shown that, for long-haul transmission systems with fiber lengths exceeding 100 km, typical channel separation of 10 GHz, and few channels, the maximum allowed input power per channel, P_max, is limited by SBS (stimulated Brillouin scattering) to about 5 dBm. As the number of channels increases, FWM (four wave mixing) becomes the limiting process with P_max of about -5 dBm, whereas above several hundred channels SRS (stimulated Raman scattering) becomes dominant with P_max of about -5 dBm. For local area networks with shorter lengths, the results are similar, except that the values of P_max are uniformly higher by about 5 dB     

Fine needle capillary cytology versus fine needle aspiration cytology--a comparison of quality between puncture techniques in the ENT area

In examining ways to improve female health care access and utilization, the magnitude of health problems must be examined before the design of solutions. Two types of barriers interfere with health care: attitudinal barriers blocking motivation to seek health care services and organizational barriers which block actual use of needed services. The major health problems of women in the United States are heart disease, cancer, stroke, lung-related diseases, intentional injuries, diabetes and HIV/AIDS. Public health has had a greater impact than high technology on the health of our nation. Balancing health care reform, changes in legislation and funding for medical education should help the United States be responsive to the challenge to move from substandard health for many women to superlative health care for all women and their family members.     

Ten-channel coherent optical fibre transmission

A laboratory ten-channel coherent fibre-optic broadband transmission system is reported. The frequency-division-multiplexed optical carriers are separated by 6 GHz and are demultiplexed by a tunable heterodyne receiver having a sensitivity of -46 dBm at a bit error rate of 10-9. In this system a maximum number of 64 channels can be installed.