Single-ended mid-infrared laser-absorption sensor for time-resolved measurements of water concentration and temperature within the annulus of a rotating detonation engine

A novel single-ended mid-infrared laser-absorption sensor for time-resolved measurements of water mole fraction and temperature was developed and deployed within the annulus of a hydrogen/air-fed rotating detonation engine (RDE). The sensor transmitted two laser beams targeting mid-infrared water transitions through a single optical port on the outer wall of the cylindrical RDE annulus and measured the backscattered radiation from the RDE inner surface using a photodetector for a round-trip path of 1.52?cm. Optimizing the sensor's optical arrangement using numerical ray tracing to minimize interference from optical emission, beam steering, and scattered laser light from window surfaces was essential to sensor performance. Scanned-wavelength-modulation spectroscopy with second-harmonic detection and first-harmonic normalization was implemented to allow for frequency-domain multiplexing of the two lasers and to suppress non-absorbing interference sources such as beam-steering and emission. Tunable diode lasers near 2551 and 2482?nm were modulated at 100 and 122?kHz, respectively, and sinusoidally scanned across the peaks of their respective water transitions at 10?kHz to provide a measurement rate of 20?kHz and detection limit of 0.5% water by mole. Experimentally derived spectroscopic parameters enabled water and temperature sensing with respective uncertainties of 7.3% and 5.3% relative to the measured values. Time-resolved and time-averaged sensor measurements of gas temperature and water vapor mole fraction allow quantitative evaluation of the combustion progress at the measurement location and thus provide a design tool for RDE optimization. Broadly, this single-ended laser sensor should find applications in other combustion systems where optical access is limited.     

Études sur la détection,la caractérisation et le dosage des aldéhydes: Méthodes d'oximation

Five methods for the estimation of aldehydes by oximation have been compared. In all the methods, a single or double branching in position α in the case of aliphatic aldehydes, and in positions 2 and 6 in the case of aromatic aldehydes, tends to lessen the accuracy (steric hindrance). Of the methods examined those of Bryant and Smith¹ and Smith and Mitchell³ are the most common.Three new oximes are described. For one of these, two modifications have been isolated, both of which are converted to acetate by the action of acetic anhydride and sodium carbonate. The question is discussed whether this is a case of the syn and anti forms of the oximo or of two polymorphic modifications.     

Decomposed enumeration of extreme points in the linear programming problem

In this paper we consider the problem of enumeration of extreme points in the linear programming problem when the matrix is of block-angular type. It is shown how decomposition methods can be used. Finally application of decomposed enumeration to the problem of computing equilibrium prices in a capital market network is given as an example.     

Experimental determination of the structure function of the pion

It was shown in the preceeding letter that dimuon production by 22 GeV pions proceeds in part through qq? annihilations in agreement with the Drell-Yan model. Using these data we extract the quark distribution function of the pion. Comparison of our structure function with that obtained from data at higher energy reveals differences compatible with the QCD calculations of the Q²-dependence (scale breaking) of the pion structure function.     

p elastic scattering in the T-meson region

We have made improved measurements of 43.8 ± 0.8, 41.3 ± 0.4 and 39.3 ± 0.8 mb for the p elastic cross sections at 1.11, 1.33 and 1.52 GeV/c laboratory momenta respectively. Sharp forward peaks in the differential cross sections with broad secondary maxima agree with previous observations [3–6]. The forward differential cross sections are (11 ± 3)% above the optical point in agreement with real amplitudes extended from lower momenta using dispersion relations [7]. The elastic cross sections do not show any structure in the s-channel. Backward differential cross sections show the onset of a “third diffraction peak” but no evidence for other structure in agreement with earlier experiments [6, 13].     

Measurement of structure-dependent K+ --> &mgr;(+)nu(&mgr;)gamma decay

We report the first measurement of a structure-dependent component in the decay K+-->&mgr;(+)nu(&mgr;)gamma. Using the kinematic region where the muon kinetic energy is greater than 137 MeV and the photon energy is greater than 90 MeV, we find that the absolute value of the sum of the vector and axial-vector form factors is |F(V)+F(A)| = 0.165+/-0.007+/-0.011. This corresponds to a branching ratio of B(SD+) = (1.33+/-0.12+/-0.18)x10(-5). We also set the limit -0. 04相似文献   

Über die Verseifung der Oxamidsäureester

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