Cone Angle Measurements Research Articles

Method of Identifying Injector Coking From the Spray Field of Mechanical and CRDi Injectors Using Intensity of Scattered Light

The influence of injector coking deposits on the spray field of single-hole mechanical port fuel injectors and multihole common rail direct injection (CRDi) injectors was studied using light scattering technique coupled with image processing and analysis. Instead of employing the traditional accelerated coking process to study injector spray field deterioration, in-service injectors were selected and cleaned using a commercial fuel system cleaning procedure. Variation in atomization characteristics of coked and cleaned injectors were observed based on the spatial distribution of fine, medium, and coarse droplets in the near-field region of the injector spray zone and analyzed as a function of the intensity of scattered light. The improvement in the atomization perceived by this method was compared with traditional techniques like spray cone angle measurement, speed characterization of spray jets, and weight reduction of injector nozzles and needles. It was observed that after the fuel system cleaning procedure, a reduction in the number of coarse droplets in the near-field region and an increase in the number of medium and finely sized droplets was observed, suggesting better atomization of fuel in the near field spray zone.

Interferometry of a reflective axicon surface with a small cone angle using an optical inner surface

Reflective axicons, widely used in optical alignment and Bessel–Gauss beam generation, require a highly accurate cone angle and surface metrology. However, current methods focus on the cone angle measurement and it is still difficult to measure the surface of a reflective axicon with a small cone angle. An interferometer measurement method using an optical inner surface is proposed to obtain the surface and cone angle simultaneously. The optical axis of the axicon and the optical inner surface should align together and be parallel to the beam light from the interferometer. The interference fringe would be obtained by the optical system consisting of the axicon and the optical inner surface. The theoretical model is established and analyzed through ray tracing theory, and is verified by optical simulation software. Fabrication errors in the axicon and the inner surface, and misalignment of the measurement setup are investigated systematically and separated in the measurement process. In the experiments, the reflective axicon with a cone angle of about 90° was measured by the proposed method, the results of which show good agreement with a stylus profiler (Taylor-Hobson PGI 3D) in cone angle trend and generatrix error. Experimental results prove the feasibility of the proposed method. This economical and effective method can be widely used with all types of reflective axicons, and it can obtain the surface error map of the axicon as well as the inner cylinder at the same time. The uncertainty and resolution of the proposed method is based on the performance of the interferometer. The uncertainty of alignment angle errors is less than 10−10 rad; the lateral resolution is 53.8 µm.

Optical method for automated measurement of glass micropipette tip geometry

Many experimental biological techniques utilize hollow glass needles called micropipettes to perform fluid extraction, cell manipulation, and electrophysiological recordings. For electrophysiological recordings, micropipettes are typically fabricated immediately before use using a “pipette puller”, which uses open-loop control to heat a hollow glass capillary while applying a tensile load. Variability between manufactured micropipettes requires a highly trained operator to qualitatively inspect each micropipette; typically this is achieved by viewing the pipette under 40–100× magnification in order to ensure that the tip has the correct shape (e.g., outer diameter, cone angle, taper length). Since laboratories may use hundreds of micropipettes per week, significant time demands are associated with micropipette inspection. Here, we have automated the measurement of micropipette tip outer diameter and cone angle using optical microscopy. The process features repeatable constraint of the micropipette, quickly and automatically moving the micropipette to bring its tip into the field of view, focusing on the tip, and computing tip outer diameter and cone angle measurements from the acquired images by applying a series of image processing algorithms. As implemented on a custom automated microscope, these methods achieved, with 95% confidence, ±0.38μm repeatability in outer diameter measurement and ±5.45° repeatability in cone angle measurement, comparable to a trained human operator. Accuracy was evaluated by comparing optical pipette measurements with measurements obtained using scanning electron microscopy (SEM); optical outer diameter measurements differed from SEM by 0.35±0.36μm and optical cone angle measurements differed from SEM by −0.23±2.32°. The algorithms we developed are adaptable to most commercial automated microscopes and provide a skill-free route to rapid, quantitative measurement of pipette tip geometry with high resolution, accuracy, and repeatability. Further, these methods are an important step toward a closed-loop, fully-automated micropipette fabrication system.

Sterically encumbered pyrrolyl ligands and their incorporation into the cycloheptatrienyl zirconium coordination sphere

An improved synthesis of 2,5-di(tert-butyl)-3,4-dimethylpyrrole (2-H, HPyr(tBu(2)Me(2))) and a subsequent reaction with KH yield K(Pyr(tBu(2)Me(2))) (2-K) in multi-gram quantities. Four different pyrrolyl (Pyr) and imidazolyl (Im) ligands were used in salt metathesis reactions with [(η(7)-C(7)H(7))ZrCl(tmeda)] (7) to afford a series of azatrozircenes: [(η(7)-C(7)H(7))Zr(η(5)-Pyr(tBu(2)))] (1-Zr), [(η(7)-C(7)H(7))Zr(η(5)-Pyr(tBu(2)Me(2)))] (2-Zr), [(η(7)-C(7)H(7))Zr(η(5)-Pyr(tBu(3)))] (3-Zr) and [(η(7)-C(7)H(7))Zr(η(5)-Im(tBu(3)))] (4-Zr), which were characterized by NMR spectroscopy and elemental analysis. In addition, the molecular structures of 2-H, 2-K·18-crown-6, 1-Zr, 2-Zr and 4-Zr were determined by X-ray diffraction analysis, revealing η(5)- rather than κ(1)-N-coordination of the N-heterocyclic ligands. Cone angle measurements on the sandwich complexes 1-Zr–4-Zr showed that their nitrogencontaining ligands belong to the class of very sterically encumbered π-ligands, but DFT calculations suggest lower stabilities compared to their all-carbon analogues.

Systematic analysis of the measurement of cone angles using high line density computer-generated holograms

Computer-generated holograms (CGHs) allow to transfer the high 2D-positioning accuracy of modern lithography equipment into high precision 3D-shape measurements, e.g. in CGH asphere metrology. In this contribution, we give a detailed look into the characterization of steep topologies with CGHs on the example of a 90 deg axicon surface, requiring rather high line densities in the hologram. Several aspects gain importance with increasing CGH line densities when measuring dimensional quantities such as the cone angle of the surface: misalignment of the setup, fabrication effects of the CGH rigorous effects of the high density grating, and effects due to wavelength variations of the interferometer. This paper presents the experimental approach for the cone angle measurement and a systematic analysis of its measurement uncertainty, focusing on the specifics of this null test CGH measurement.

Development and validation of a theoretical model for diesel spray penetration

A research on the diesel spray injected into stagnant ambient air in a chamber is reported in this paper. The main objective of the investigation is to carry out an in-depth analysis on the influence of injection parameters on the spray internal dynamics and spray macroscopic characteristics. As a result of a theoretical approach based on momentum flux conservation along the sprays' axis, a model which predicts the spray axis velocity and spray tip penetration is obtained. Measurements of momentum flux and spray cone angle are needed in order to predict axis velocity and spray penetration. The chamber density is assumed to be constant and equal to the density of the pressurized air inside the chamber. A Gaussian radial profile is assumed for the axial velocity. Experimental results from a conventional common rail injection system with five axisymmetric nozzles tested in a wide range of injection pressure values and density conditions have been used in order to obtain additional information of the model and also for validation purposes. These experimental results include a large number of momentum flux (impact force), spray tip penetration and spray cone angle measurements.

Rotational barriers in dialkylaminochlorophosphines: methyl-substituted piperidinochlorophenylphosphines

Barriers to rotation about the P–N bond in a series of substituted piperidinochlorophenylphosphines were measured. The barriers for piperidine, 2-methylpiperidine and cis-2,6-dimethylpiperidine are the same within experimental error. The thermal condensation of the corresponding bis(piperidino)phosphine oxides with Mo(CO) 6 show that only the cis-2,6-dimethyl compound produces significant quantities of the [R 2NPO] 4[Mo(CO) 4] 2 complex. These observations are explained in terms of the steric requirements of the various amines and aminophosphines via cone angle measurements. Condensation of the mixed phosphine oxide, ( iPr 2N)(Et 2N)PHO, with Mo(CO) 6 produces [Et 2NPO] 4[Mo(CO) 4] 2.

Inferring the scale height of the lunar nightside double layer

Earlier analyses of Lunar Prospector (LP) data found that the shadowed lunar surface charges negative. The potential difference between the surface and LP has unexplained dependences on solar zenith angle and tip angle. The dependence on tip angle may arise because electrons with pitch angles close to the loss cone angle on field lines with higher tip angles encounter a smaller average potential before reflecting (the technique used to infer potentials relies upon loss cone angle measurements). The correlation may therefore be due to a systematic measurement error. However, since this “measurement error” depends upon the ratio of gyroradius to double layer scale height, it allows us to estimate the scale height. By comparing data with the results of particle tracing simulations, we estimate an average nightside scale height of a few km. This is somewhat larger than the electron Debye length, but much smaller than recent theoretical estimates.

Rapid Access to Diverse Arrays of Chiral 3,4-Diazaphospholanes We thank the Department of Energy, Office of Basic Energy Sciences for financial support of this work. All crystal-structure determinations were performed by Dr. Doug Powell or Dr. Ilyea Guzei. The cone-angle measurements were made with the gracious assistance of Dr. David White of the UNC-Wilmington.

Effektive Liganden für Übergangsmetalle: Ausgehend von einfachen primären Phosphanen, Hydrazinen und Aldehyden gelingt die Zweistufensynthese einer Vielzahl chiraler fünfgliedriger Phosphacyclen wie 1–3.

Experimental Measurements of Hot Electrons Generated by Ultraintense (>1019W/cm2) Laser-Plasma Interactions on Solid-Density Targets

We present the first in-target measurements of the electrons produced by an ultraintense $(Ig{10}^{19}\mathrm{W}/{\mathrm{cm}}^{2})$ laser pulse incident on a massive solid target. Total conversion efficiency, mean electron energy, and electron cone-angle measurements are presented. A relationship between the target material and the mean electron energy is also discussed.

Tangent systems for cone angle measurement

Tangent systems for cone angle measurement

Critical behavior in spin-reorientation phase transitions: (ErxR1-x)2Fe14B (R=Nd, Dy) magnets.

The critical behavior of spin-reorientation phase transitions in the hard magnetic intermetallics (${\mathrm{Er}}_{\mathrm{x}}$${\mathrm{R}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${)}_{2}$${\mathrm{Fe}}_{14}$B (R=Dy and Nd) has been studied with ac low-field susceptibility, ${\ensuremath{\chi}}_{H}$, and cone-angle measurements. A simple model for scaling the low-field susceptibility has been developed and applied to the present series of compounds. The critical exponents for ${\ensuremath{\chi}}_{H}$ have been determined for some well-behaved compounds.

Influence of design concept and liquid properties on fuel injector performance

An experimental investigation of the influence of design concept and liquid properties on fuel injector performance of airblast atomizers is carried out. Three injectors with distinctly different fuel filming concepts were employed in this program. In the experiments, the nozzle operating conditions (namely, air/liquid ratio and air pressure drop) and liquid properties were varied. Drop sizes were measured with a laser diffraction instrument and a photographic technique was employed for cone angle measurement. The results indicate that the method of spreading the liquid into a film has a significant effect on atomization quality. Also, surface tension has the most dominant effect on mean drop size. The drop size distribution data followed closely the modified Rosin-Rammler type under almost all conditions. Equations to correlate mean drop sizes to distribution parameters were derived to facilitate the prediction of the range of droplets in the spray.

A precise comparison of the neutron threshold energy and the Q value for the Li 7(p, n)Be 7 reaction

The Q value of the Li 7(p, n)Be 7 reaction has been determined by measuring the angle of the cone of neutrons emitted in the forward direction at a proton energy 20 keV above the threshold energy. The proton energy was measured relative to the energy at which (neutron yield) 2 3 extrapolates to zero. The cone-angle was determined by fitting the measured neutron yield at the edge of the cone with a calculated yield. With an energy spread of 240 eV in the proton beam and a detector resolution of 0.7°, the cone-angle was measured to an accuracy of 0.2°. If 1880.6±0.3 keV is taken for the experimentally determined neutron threshold, the cone-angle measurement gives Q = −1644.38±0.17 keV relative to this energy point taken with no error. These measurements also constitute a precise check on the validity of the kinematic equation for nuclear reaction dynamics.