Abstract: A display subsystem for a virtual image generation system for use by an end user comprises a planar waveguide apparatus, an optical fiber, at least one light source configured for emitting light from a distal end of the optical fiber, and a collimation element mounted to a distal end of the optical fiber for collimating light from the optical fiber. The virtual image generation system further comprises a mechanical drive assembly to which the optical fiber is mounted to the drive assembly. The mechanical drive assembly is configured for displacing the distal end of the optical fiber, along with the collimation element, in accordance with a scan pattern. The virtual image generation system further comprises an optical waveguide input apparatus configured for directing the collimated light from the collimation element down the planar waveguide apparatus, such that the planar waveguide apparatus displays image frames to the end user.

Abstract: A virtual image generation system comprises a planar optical waveguide having opposing first and second faces, an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly into the planar optical waveguide as an in-coupled light beam, a first orthogonal pupil expansion (OPE) element associated with the first face of the planar optical waveguide for splitting the in-coupled light beam into a first set of orthogonal light beamlets, a second orthogonal pupil expansion (OPE) element associated with the second face of the planar optical waveguide for splitting the in-coupled light beam into a second set of orthogonal light beamlets, and an exit pupil expansion (EPE) element associated with the planar optical waveguide for splitting the first and second sets of orthogonal light beamlets into an array of out-coupled light beamlets that exit the planar optical waveguide.

Abstract: A process and system for the analysis and/or control of a mixture of liquid hydrocarbons and biodiesel to determine biodiesel concentration includes a) measuring the near infrared absorption in at least two of the bands of two absorption bands from a portion of the range of 800-2500 nm; in particular 1100-2500 nm which are used to quantify the biodiesel content. b) taking each of the absorbances measured, or a mathematical function thereof, c) performing at least one mathematical computing or statistical treatment using the above absorbances or functions as individual independent variables, d) assigning and applying weighting constants or their equivalents to the independent variables, and, optionally e) applying the above steps using known compositions to calibrate the instrument and determine the weighting constants or equivalents, and further optionally f) outputting a signal indicative of the biodiesel concentration in the mixture, based on the absorbances or functions.

Abstract: A monitoring of catalytic cracking processing is provided which uses near infrared (NIR) analysis to characterize cracking feeds, intermediates and products for chemical and physical properties such as saturates, monoaromatics, diaromatics, triaromatics, tetraaromatics, polar aromatics, total aromatics, thiophenes, distillation points, basic nitrogen, total nitrogen, API gravity, total sulfur, MCRT and % coker gasoil and the resulting characterization thereof. The NIR results can be used in FCC simulation software to predict unit yields and qualities.

Abstract: Reformulated gasoline (RFG) testing recently required by EPA involves measuring sulfur, olefin, aromatic contents, Reid Vapor Pressure (RVP), and benzene, distillation properties, plus total air pollutants (TAPs), volatile organic carbon (VOC), and nitrogen oxides (NOx). Measuring driveability, although not required, is desirable. All of these tests can be conducted by spectrometer, preferably in the IR range, more preferably in the NIR range, and most preferably by a single instrument operating at high-correlation wavelengths. Importantly, VOC, TAP, NOx, and RVP may be correlated to IR absorbance at certain bands. Statistical methods including PLS, MLR, PCR, and neural networks can be used and derivatives of first, particularly second, or other orders can be used. Results can be displayed on a single screen.

Abstract: Asphaltene concentration of a hydrocarbon feed is measured by IR spectroscopy using mid-range IR frequencies between 3800 cm.sup.-1 and 650 cm.sup.-1 (corresponding to wavelengths between 2630 nanometers (nm) and 15,380 nm) together with mathematical techniques and statistical techniques in which measurements of absorption are made, and combines these with multiple regression analysis, or other statistical technique and modeling to determine asphaltene concentration. The output signal can be used to control refinery and chemical processes, e.g., atmospheric crude column, vacuum distillation column, solvent deasphalting and visbreaking.

Abstract: A Fourier-Transform Raman spectrometer was used to collect the Raman spectra of (208) commercial petroleum fuels. The individual motor and research octane numbers (MON and RON, respectively) were determined experimentally using the industry standard ASTM knock engine method. Partial Least Squares (PLS) regression analysis can be used to build regression models which correlate the Raman spectra (175) of the fuels with the experimentally determined values for MON, RON, and pump octane number (the average of MON and RON) of the fuels. Each of the models was validated using leave-one-out validation. The standard errors of validation (SEV) are 0.415, 0.535, and 0.410 octane numbers for MON, RON, and pump octane number, respectively. By comparing the standard error of validation to the standard deviation for the experimentally determined octane numbers, it is evident that the accuracy of the Raman determined values is limited by the accuracy of the training set used in creating the models.

Abstract: A distributed Bragg reflector (DBR) diode laser is used as excitation source for fiber optic Raman spectroscopy utilizing charge coupled device (CCD) detection and an image-corrected spectrograph. The DBR diode laser is superior to index guided diode lasers (Fabry-Perot) for elimination of mode hopping, elimination of frequency hysteresis as a function of both temperature and current changes, and reduction in laser broadband emission. These advantages allow the DBR laser to be used in industrial process control applications which are too demanding for index guided diode lasers.

Abstract: In addition to analysis in the infrared spectra of hydrocarbon group types, it has now been found that certain hydrocarbon species, including preferably aromatic species such as benzene, toluene, xylene, and alkyl benzenes such as ethyl benzene, can be determined by measuring absorption in certain selected wavelengths in the infrared spectra, then manipulating the data, e.g., preferably by taking the first or higher derivative, and applying statistical techniques, preferably multiple linear regression (MLR) to provide an output signal indicative of the concentration of the particular specie. The output signal can be used to control refinery and chemical processes, e.g., reforming, catalytic cracking, alkylation and isomerization. In manufacturing reformulated fuels, government regulations can be complied with by utilizing the invention to blend fuels which have a maximum of benzene or other regulated components.

Abstract: Benzene and substituted aromatic hydrocarbons can be predicted within .+-.0.31% vol or better, using Raman NIR spectroscopy and multivariate analysis, with optional fiberoptics multistreaming, preferably with Partial Least Squares regression analysis. The resulting signal can be used to control concentration of such compounds in product to desired levels.

Abstract: Oxygenated hydrocarbons can be predicted within .+-.0.2% wt or better, using Raman NIR spectroscopy and multivariate analysis, with optional fiberoptics multistreaming. The resulting signal can be used to control concentration of such compounds in product to desired levels.

Abstract: Mid-distillate hydrocarbon fuels, preferably having initial boiling points above 350.degree. F., are separated e.g. by prep-HPLC into non-aromatic and aromatic fractions which are used to set 0% aromatics (the non-aromatics) and 100% aromatics (the aromatics) on an NIR spectrophotometer. From NIR aromatic band absorbances of unknown samples, their percent aromatics is determined using this two-point calibration and the Beer-Lambert equation. Preferred NIR bands of 1650-1700 and 2120-2256 exhibit excel lent correlation with aromatics content.

Abstract: Mid-distillate hydrocarbon fuels, preferably having initial boiling points above 350.degree. F., are separated e.g. by prep-HPLC into non-aromatic and aromatic fractions which are used to set 0% aromatics (the non-aromatics) and 100% aromatics (the aromatics) on an NIR spectrophotometer. From NIR aromatic band absorbances of unknown samples, their percent aromatics is determined using this two-point calibration and the Beer-Lambert equation. Preferred NIR bands of 1650-1700 and 2120-2256 exhibit excellent correlation with aromatics content. Also similar techniques measure sulfur through correlation with the benzothiophenic band and its overtones and combination bands, or possibly directly.

Abstract: Mid-distillate hydrocarbon fuels, preferably having initial boiling points above 350.degree. F., are separated e.g. by prep-HPLC into non-aromatic and aromatic fractions which are used to set 0% aromatics (the non-aromatics) and 100% aromatics (the aromatics) on an NIR spectrophotometer. From NIR aromatic band absorbances of unknown samples, their percent aromatics is determined using this two-point calibration and the Beer-Lambert equation. Preferred NIR bands of 1650-1700 and 2120-2256 exhibit excellent correlation with aromatics content.

Abstract: A lintel fabricated of an elongated lightweight metal plate having rigidifying beam means affixed thereto and extending longitudinally thereof.