Automated reflection photoelasticity : digital data acquisition and use.

Automation of reflection photoelasticity has simplified the stress and strain analysis of real engineering components and reduced analysis time. However, images obtained from automated reflection photo elasticity contain noise and accuracy of the analysis will be affected by the degraded intensity images. In the present study, major sources of noise in automated reflection photoelasticity have been found to be the photoelastic coating and the electronic instrumentation. An automated reflection polariscope PSIOS developed by Patterson and Wang (1998) for the simultaneous observation and capture of four phase-stepped photo elastic images was used as an example. The majority of the noise is in the high spatial frequency domain. The zero-phase, low pass Butterworth filter was found to be the most effective and flexible smoothing method for reducing the effect of noise in the intensity images. Results from experiments performed for assessing the ability of the PSIOS indicated that it is capable of yielding accurate results for the stress analysis of real components in both static and dynamic conditions and that it is fast and easy to use. Full-field experimental methods are often used to validate the stress distribution generated from numerical analysis. A common practice is to plot data along a line across the maps and to include both experimental and numerical results on the same axes. This approach is used widely and usually a reasonable, quantitative conclusion can be made. However, it cannot obtain more information about the relationship between the stress maps. Another method is to compare hot spots on experimental maps to the numerical maps. If the hot spots on the two maps match well, the numerical method is considered valid. However, when designs are being optimised for weight or crack paths are being investigated, comparison of the positions of the hot spots alone will not be enough and the correlation elsewhere in the data field should be taken into account. It has been shown that fit between the stress map from an experimental method and the stress map from the numerical analysis can be represented by a statistical parameter, the scaled standard deviation. An evaluation of the method was performed using stress maps from transmission photoelasticity, thermoelasticity and the finite element method as examples. The results from experiments using a curved tiebar, a circular ring and a real engineering component in this case, a race car hub carrier indicated that the scaled standard deviation represents the fitness between the two stress maps. If the scaled standard deviation is smaller than 0.1, then the experimental map and the numerical map can be considered to be in good agreement

Anti-Inflammatory Effects of Cumin Essential Oil by Blocking JNK, ERK, and NF- κ

Cumin seeds (Cuminum cyminum L.) have been commonly used in food flavoring and perfumery. In this study, cumin essential oil (CuEO) extracted from seeds was employed to investigate the anti-inflammatory effects in lipopolysaccharide- (LPS-) stimulated RAW 264.7 cells and the underlying mechanisms. A total of 26 volatile constituents were identified in CuEO by GC-MS, and the most abundant constituent was cuminaldehyde (48.773%). Mitochondrial-respiration-dependent 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction assay demonstrated that CuEO did not exhibit any cytotoxic effect at the employed concentrations (0.0005–0.01%). Real-time PCR tests showed that CuEO significantly inhibited the mRNA expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), interleukin- (IL-) 1, and IL-6. Moreover, western blotting analysis revealed that CuEO blocked LPS-induced transcriptional activation of nuclear factor-kappa B (NF-κB) and inhibited the phosphorylation of extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). These results suggested that CuEO exerted anti-inflammatory effects in LPS-stimulated RAW 264.7 cells via inhibition of NF-κB and mitogen-activated protein kinases ERK and JNK signaling; the chemical could be used as a source of anti-inflammatory agents as well as dietary complement for health promotion

Spatial Interference: From Coherent To Incoherent

It is well known that direct observation of interference and diffraction pattern in the intensity distribution requires a spatially coherent source. Optical waves emitted from portions beyond the coherence area possess statistically independent phases, and will degrade the interference pattern. In this paper we show an optical interference experiment, which seems contrary to our common knowledge, that the formation of the interference pattern is related to a spatially incoherent light source. Our experimental scheme is very similar to Gabor's original proposal of holography[1], just with an incoherent source replacing the coherent one. In the statistical ensemble of the incoherent source, each sample field produces a sample interference pattern between object wave and reference wave. These patterns completely differ from each other due to the fluctuation of the source field distribution. Surprisingly, the sum of a great number of sample patterns exhibits explicitly an interference pattern, which contains all the information of the object and is equivalent to a hologram in the coherent light case. In this sense our approach would be valuable in holography and other interference techniques for the case where coherent source is unavailable, such as x-ray and electron sources.Comment: 8 pages, 5 figure

Next-to-leading order QCD predictions for the hadronic WHWH+jet production

We calculate the next-to-leading order(NLO) QCD corrections to the $WH^0$ production in association with a jet at hadron colliders. We study the impacts of the complete NLO QCD radiative corrections to the integrated cross sections, the scale dependence of the cross sections, and the differential cross sections ($\frac{d \sigma}{d\cos\theta}$, $\frac{d \sigma}{dp_T}$) of the final $W$-, Higgs-boson and jet. We find that the corrections significantly modify the physical observables, and reduce the scale uncertainty of the LO cross section. Our results show that by applying the inclusive scheme with $p_{T,j}^{cut}=20 GeV$ and taking $m_H=120 GeV$, $\mu=\mu_0\equiv\frac{1}{2}(m_W+m_H)$, the K-factor is 1.15 for the process $p\bar p \to W^{\pm}H^0j+X$ at the Tevatron, while the K-factors for the processes $pp \to W^-H^0j+X$ and $pp \to W^+H^0j+X$ at the LHC are 1.12 and 1.08 respectively. We conclude that to understand the hadronic associated $WH^0$ production, it is necessary to study the NLO QCD corrections to $WH^0j$ production process which is part of the inclusive $WH^0$ production.Comment: 26 pages, 27 figures, accepted by Phys. Rev.

Simulation Research on Driving Behaviour of Autonomous Vehicles on Expressway Ramp Under the Background of Vehicle-Road Coordination

Constructing a risk model with the subject of autonomous vehicles to screen out the vehicles of potential conflicts and analyze their choices under different strategies. Based on the co-simulation of Python and SUMO, establishing a model of on-ramp merge driving behaviour of autonomous vehicles based on non-cooperative static game. Under this model, the experiment results that the average speed in the merging area is increased by 12.7%, the standard deviation of the average speed is reduced by 35.46%, and the number of the vehicles successfully merged before the end of the merging area is 4.86 times that of traditional method, indicate that the model can effectively help the vehicles be merged and improve the traffic efficiency to a certain extent

Simulation and application of loose tooling forging for heavy grinding roller shaft forgings

The grinding roller shaft is a key part of the grinding roller. It has a step-shaped shaft with different round cross-sections and 1850 mm × 1110 mm rectangular cross-section. If the general method of free forging is used, the upsetting diameter of ingot will reach 2900 mm, and 8400 t hydraulic press current will not be produced so that the loose tooling forging process is to be used. The loose tooling forging process of rectangular flange has been researched by using DEFORM-3D simulation software and establishing a reasonable forging process. The production results reveal that the heavy forgings used as grinding roller shafts can be successfully produced with the present 8400 t capacity hydraulic presses. The eligible forgings have proved the rationality of the technical process