Prediction of in-use emissions of heavy-duty diesel vehicles from engine testing

A model of a heavy-duty vehicle driveline with automatic transmission has been developed for estimating engine speed and load from vehicle speed. The model has been validated using emissions tests conducted on three diesel vehicles on a chassis dynamometer and then on the engines removed from the vehicles tested on an engine dynamometer. Nitrogen oxide (NOx) emissions were proportional to work done by the engine. For two of the engines, the NOx/horsepower(HP) ratio was the same on the engine and on the chassis dynamometer tests. For the third engine NOx/HP was significantly higher from the chassis test, possibly due to the use of dual engine maps. The engine certification test generated consistently less particulate matter emissions on a gram per brake horsepower-hour basis than the Heavy Duty Transient and Central Business District chassis cycles. A good linear correlation (r2 = 0.97 and 0.91) was found between rates of HP increase integrated over the test cycle and PM emissions for both the chassis and the engine tests for two of the vehicles. The model also shows how small changes in vehicle speeds can lead to a doubling of load on the engine. Additionally, the model showed that it is impossible to drive a vehicle cycle equivalent to the heavy-duty engine federal test procedure on these vehicles.     

An overview of a free-market approach to climate change and conservation

This paper describes the convergence of environmental and financial markets, reviews the evolution of market-based environmental programmes as an example of the seven-stage evolutionary process witnessed in a variety of markets and summarizes the emergence of greenhouse-gas-mitigation markets and their potential role in advancing land stewardship, biodiversity and other environmental services. Emissions trading has been developed to meet the demand to reduce pollution while avoiding economic disruption. Consistent with the seven-stage pattern of market evolution, the US programme to reduce the damage from acid rain established a standardized environmental commodity, developed 'evidence of ownership' necessary for financial instruments and provided the infrastructure to efficiently transfer title. The success of the system in reducing pollution at low cost has provided a model for other market-based environmental protection initiatives. The demand for cost-effective action to reduce the threat of climate change has initiated the same evolutionary process for markets to reduce greenhouse-gas emissions. Many of the land- and forest-management practices that can capture and store atmospheric CO(2) can also provide other environmental benefits, such as biodiversity preservation and enhanced water quality. The presence of a carbon-trading market will introduce a clear financial value for capture and mitigation of CO(2) emissions, thus introducing a new source of funding for land stewardship and forest rehabilitation. The market is now emerging through a variety of 'bottom-up' developments being undertaken through governmental, multilateral, private-sector and non-governmental-organization initiatives. The extension of markets to other emerging environmental issues is now underway, and the linkages between environmental sustainability and capital markets are being more deeply understood. The early evidence indicates that environmental sustainability can be compatible with maximization of shareholder value.     

Contact conductivity detection in poly(methyl methacrylate)-based microfluidic devices for analysis of mono- and polyanionic molecules

An on-column contact conductivity detector was developed for the analysis of various mono- and polyanionic compounds separated by electrophoresis chips fabricated in poly(methyl methacrylate) (PMMA) using hot embossing techniques from Ni electroforms. The detector consisted of a pair of Pt wires (127 microm diameter) with an end-to-end spacing of approximately 20 microm and situated within the fluidic channel. The waveform applied to the electrode pair was a bipolar pulse with a frequency of 5.0 kHz and was used to reduce the charging current from measurement so that the current recorded at the end of one pulse is more representative of the solution conductivity. Using the detector, separations of amino acids, peptides, proteins, and oligonucleotides were demonstrated. For the amino acids and peptides, free-solution zone electrophoresis was performed. A calibration plot for the amino acid alanine was found to be linear from approximately 10 to 100 nM in a carrier electrolyte consisting of 10 mM triethylamonium acetate. The concentration detection limit was found to be 8.0 nM, with the corresponding mass detection limit equal to 3.4 amol (injection volume = 425 pL). The protein separations with conductivity detection were performed using MEKC, in which the carrier electrolyte contained the anionic surfactant sodium dodecyl sulfate (SDS) above its cmc. Near baseline resolution was achieved in the PMMA microchip for a solution containing 8 different proteins. In the case of the DNA fragments, capillary electrochromatography was used with a C18-modified PMMA chip and a carrier electrolyte containing an ion-pairing agent.     

Detection of guaiacol produced by Alicyclobacillus acidoterrestris in apple juice by sensory and chromatographic analyses, and comparison with spore and vegetative cell populations

Spoilage of fruit juice by Alicyclobacillus acidoterrestris is characterized by a distinct medicinal or antiseptic off odor attributed to guaiacol, a metabolic by product of the bacterium. Detection of low populations of A. acidoterrestris that would precede sensory detection of guaiacol would enable juice processors to select appropriate processing and storage conditions that would minimize or eliminate spoilage. The objective of this study was to determine the recognition threshold of guaiacol in apple juice by sensory analysis and the population of A. acidoterrestris and incubation time at 21 and 37 degrees C necessary for chemical detection of guaiacol. Commercially sterilized apple juice (pH 3.54 +/- 0.04, 11.3 +/- 0.3 degrees Brix) was inoculated with a five-strain mixture of A. acidoterrestris spores (2.98 log10 CFU/ml) and stored at 21 or 37 degrees C for up to 61 days. Using an experienced sensory panel and the forced-choice ascending concentration method of limits, the best estimate threshold (BET) for recognition of guaiacol added to uninoculated apple juice was 2.23 ppb. Numbers of A. acidoterrestris spores and cells in inoculated juice remained constant during the 61-day storage period; however, the panel detected (P < or = 0.01) guaiacol in juice stored at 37 degrees C within 8 days. At three of four sampling times ranging from 13 to 61 days at which the sensory panel detected (P < or = 0.001) guaiacol, concentrations of 8.1 to 11.4 ppb were detected by chromatographic analysis. The panel detected (P < or = 0.1 to P < or = 0.01) guaiacol in five samples stored at 21 to 37 degrees C for 8 to 61 days in which the compound was not detected by chromatographic analyses. It appears that guaiacol content in apple juice inoculated with A. acidoterrestris is not always correlated with numbers of cells, and the limit of sensitivity of chromatographic quantitation of the compound is higher than the BET.     

Evaluation of a material parameter extraction algorithm using MRI-based displacement measurements

The performance of an inversion algorithm is investigated when applied to measured displacement data for a determination of the material parameters /sup /spl lambda/+2/spl mu////sub /spl rho// (longitudinal wave velocity squared) and /sup /spl mu////sub /spl rho// (shear wave velocity squared) throughout an inhomogeneous test phantom. The vector displacement components throughout a test phantom subject to monochromatic shear excitation measured in time using magnetic resonance imaging (MRI) were temporally Fourier transformed to extract the component of monochromatic excitation, and the data was delivered to the inversion algorithm. A series of inversions is presented demonstrating the effects of subsequent wavenumber filtering, polarization selection, and variation in the size of the incremental volume elements. The resulting performance is assessed, and recommendations for future efforts are discussed.     

Spectral Differentiation of Trace Concentrations of NO(2) from NO by Laser Photofragmentation with Fragment Ionization at 226 and 452 nm: Quantitative Analysis of NO-NO(2) Mixtures

Laser-induced photofragmentation with fragment ionization is used to detect and spectrally differentiate trace concentrations of NO(2) from NO in NO-NO(2) mixtures. A laser operating near 226 or 452 nm ionizes the target molecules, and the resulting electrons are collected with miniature electrodes. NO is detected by (1 + 1) resonance-enhanced multiphoton ionization by means of its A (2)?(+) ? X (2)? (0, 0) transitions near 226 nm, whereas NO(2) is detected near 226 nm by laser photofragmentation with subsequent NO fragment ionization by means of both its A (2)?(+) ? X (2)? (0, 0) and (1, 1) transitions. The NO fragment generated from the photolysis of NO(2) is produced rovibrationally excited with a significant population in the first vibrational level of the ground electronic state (X (2)?, upsilon? = 1). In contrast, ambient NO has a room-temperature, Boltzmann population distribution favoring the lowest ground vibrational level (X (2)?, upsilon? = 0). Thus discrimination is possible when the internal energy distributions of both fragment NO and ambient NO are probed. We also demonstrate this approach using visible radiation, further simplifying the experimental apparatus because frequency doubling of the laser radiation is not required. We measured up to three decades of NO-NO(2) mixtures with limits of detection (signal-to-noise ratio of 3) in the low parts per billion for both NO and NO(2) for a 10-s integration time using both ultraviolet or visible radiation.     

Stimulated light scattering in transparent liquid particles: effect of the descartes ring

We consider some peculiarities of the evolution of processes of stimulated scattering in liquid transparent particles in the presence of ponderomotive action of a light field. We observed the occurrence of sharp deformations in the Descartes ring zone, which exceeds by more than 1 order of magnitude the deformations of the remaining particle surface. Investigation of the dynamics of the evolution of droplet deformations has made it possible to consider these deformations as the main cause of suppression of stimulated scattering indicated in the experiments. An analytical expression was derived to evaluate the decrease of the Q factor of droplet quasi-normal eigenmodes caused by perturbation of the particle shape from the spherical. Our study revealed that the larger the Q factor of the droplet eigenmodes, the greater the influence of surface deformation.     

Integrating microfabricated fluidic systems and NMR spectroscopy

The philosophy of miniature total analysis systems (mu-TAS) hinges on the integration of multiple chemical processing steps and the means of analyzing their results on the same miniaturized system. We have constructed chip-based capillary electrophoresis (CE) devices equipped with an integrated planar radio-frequency detector coil used for nuclear magnetic resonance spectroscopy (NMR). Separations were accomplished in the devices, but satisfactory NMR spectra could only be obtained from samples of high concentration. The relative sensitivity is explained and the scaling law dichotomy of CE and NMR explored.     

Retrospective analysis of the accuracy of conversion equations and multiple-trait, across-country evaluations of Holstein bulls used internationally

In 1995, the multiple-trait across country genetic evaluation procedure replaced regression-based conversion equations as the preferred method for international genetic comparisons of dairy bulls. In the present study, February 1999 estimated breeding values of 632 foreign Holstein bulls that were used in Canada, Germany, Italy, The Netherlands, Sweden, and the US were compared with January 1995 predictions from home country data only. January 1995 predicted breeding values for each importing country were calculated using three methods: the multiple-trait, across-country evaluation procedure; conversion equations based on the multiple-trait, across-country evaluations; and conversion equations based on the Wilmink method. Mean correlations between 1999 estimated breeding values in the importing countries and 1995 predictions from international data were from 0.76 to 0.81 for all methods. The multiple-trait, across-country evaluation procedure is expected to lead to selection of different bulls, because bulls were allowed to be ranked differently in each country, but no significant increase in accuracy of selection was observed. The lack of improvement in accuracy of prediction was most likely due to limitations in data structure. International genetic comparisons are largely driven by data from a relatively small number of evaluated bulls with exported semen. Data from siblings and more distant relatives provide only weak, indirect genetic links between countries, and inclusion of such data seems to provide a minimal improvement in accuracy. Limitations in data structure might be alleviated by methods that define environments by climate or management factors rather than country borders.     

Reproductive performance of Holstein cows receiving somatotropin

Some dairy producers resist using bovine somatotropin (bST) beginning at 9 wk postpartum because of the concern that fertility is compromised. We conducted a trial with a total of 205 Holstein cows, 100 multiparous and 105 primiparous, to evaluate reproductive performance in two high producing herds in Arizona and southern California. Rolling herd averages for both herds for milk production exceeded 10,700 kg/yr. Data were collected for cows calving December 1996 through August 1997. The voluntary waiting period was 60 d postcalving, with cows randomly assigned to receive bST or no treatment (controls). In the 180-d interval after calving, 65.4% (68/104) of the control cows were diagnosed pregnant. With bST-treated cows, 48.5% (49/101) were pregnant in that same interval. A chi-square value from a linear model indicated that pregnancy outcome differed significantly between treatment groups. With a similar method of analysis, first-service conception rate was not significantly different between treatment groups. An extended voluntary wait and breeding interval is recommended for cows receiving bST, similar to suggestions from other published reports.