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A kind of meridional concept which has a shape of contraction-expansion (Con-Exp) was applied to the ram-rotor in the paper, and detailed numerical simulation to understand the impact of meridional shape and geometric characteristic angle on the aerodynamic behavior of ram-rotors has been undertaken. Compared to baseline, there was a positive effect in intensifying shock train and suppressing low momentum fluid in Con-Exp scheme, and the pressure ratio and efficiency of Con-Exp scheme increased by 2.075% and 3.160%, respectively. When the contracting angle was increasing, supersonic flow at and after throat region accelerated remarkably, and the static pressure rise was decreased gradually. The terminating shock train was transformed to terminating shock, and the efficiency of ram-rotor was unfavorable to improve due to low throttle extent. As expanding angle rose, the terminating shock moved forward and turned to shock train gradually. The pressure rise capacity and throttling ability of ram-rotor were raised. More low momentum fluid was accumulated near the middle and upper flow-path, yielding greater flow loss at large expanding angle.

Numerical investigation of ram-rotors with different strake profiles and maximum thickness positions has been performed. Four types of strake profiles are modeled firstly and the results show that total pressure ratio and adiabatic efficiency of the ss-sym, ss-ps, and ss-ss schemes are improved in different degrees compared with the sym-sym scheme, in which the comprehensive performance of the ss-ss scheme is relatively optimal, and its total pressure ratio and adiabatic efficiency are increased by 26.275% and 2.554%, respectively. The results of different strake maximum thickness positions indicate that the total pressure ratio and adiabatic efficiency are gradually increasing with the backward movement of starting point of maximum thickness, and the pressure rising capacity can come to a peak value. As the ending point of maximum thickness moves backward, there both exist peak values of the total pressure ratio and adiabatic efficiency. Compared with the ss-ss scheme, the scheme that combines optimal starting and ending point positions of maximum thickness takes advantage of these two schemes to achieve a higher aerodynamic performance, with total pressure ratio and adiabatic efficiency increasing 0.182% and 1.928%, respectively. Moreover, in comparison to the original sym-sym scheme, the total pressure ratio and the adiabatic efficiency of the combination scheme are improved much by 26.50% and 4.53%.

In order to research the influence of adjustable vane on the aerodynamic performance of the ram-rotor test system, FLUENT software has been adopted to simulate the flow passage of the ram-rotor test system numerically. The vane opening is controlled by changing the stagger angle of the vane blades. Results show that flow uniformity of vane outlet is influenced by the vane openings, which has an impact on the aerodynamic loss to some extent. Total pressure ratio, adiabatic efficiency and mass flow rate can be regulated by different openings of the vane. Compared with -8° vane opening, top efficiency of the ram-rotor increases by about 13.8% at +6° opening. And total pressure ratio drops by 5.87%. The rising opening increases the relative Mach number at inlet of the ram-rotor and weakens the intensity of the tip clearance leakage, which comes to a decreasing aerodynamic loss.

In order to diminish the flow loss in the ram-rotor and improve its aerodynamic performance, the effect of forward and backward swept leading edge on flow field and shock pattern in the ram-rotor was investigated using 3-dimensional steady CFD. Ram-rotors with sweeping angles of −60°, −30°, −15°, 0°, 15°, 30°, 60° were modeled, and ram-rotor performance, shock pattern and leakage flow in different swept schemes were the main focuses of attention. The effect of sweeping angle was also discussed in this paper. It has been found that forward sweep makes performance curves move to high mass flow rate zone in the performance map. Meanwhile, strake tip loading decreases, and maximum adiabatic efficiency increases by 0.31% compared to baseline ram-rotor. Contrary to the forward swept scheme, performance curves of backward sweep schemes shift to small mass flow rate zone, and the tip leakage near front part of strake is enhanced. Backward sweep plays a positive role in improving pressure ratio with a maximum increment of 0.46% at peak efficiency point, but causes a high flow loss. As sweeping angle changes, there is an optimum angle value to get a high performance.

As the Internet has become a popular avenue for users to seek health-related information, the prevalence of online rumors represents a growing concern. If users trust and share bogus health information on the Internet, repurcussions could be serious. Therefore, this paper examines how users' intention to trust and share rumors vary as a function of three factors: length, sentiment of rumors, and presence of pictures. The individual difference of risk propensity is also taken into account. Data were collected from 110 participants using a 2 (length of rumors: short or long) × 2 (rumor sentiments: positive or negative) × 2 (presence of pictures: present or absent) within-participants web-based experiment. Results indicate that long rumors as well as those without pictures were likely to be trusted and shared regardless of individuals' risk propensity. However, the relationship between rumor sentiment and intention was not always consistent between risk-averse and risk-seeking individuals. Implications of the results for both theory and practice are highlighted.

Device detection and diagnosis technology is one of the key technologies to guarantee safe, reliable and economical production, to achieve scientific management and to maximize efficiency of the equipment. Off-line diagnosis, which is also called point inspection, has been applied in most modern large-scale enterprises. According to the running state of the point inspection management system of Coal Washing and Processing in Shendong Mine Group Co…LTD, this paper mainly gives a brief introduction to information point inspection management system in modern coal preparation plant in terms of the architecture, implementation, characteristics and workflow of it, and offer the experience for other enterprises of our country to draw on.

Based on measuring inhibitor effective component N content, chloride removal efficiency and steel polarization resistance, influences of technical parameters of concrete and electric charge amount on the inhibitor electromigration anticorrosion efficiency were described. The results indicated that inhibitor electromigration anticorrosion technology could remove chloride ion, and inhibitor group could move to steel surface so rapidly that corrosive steel could return into passive state, to meet the anticorrosion aim for steel.

In this paper, 2.5D SiO2f/SiO2 composites were fabricated via sol-gel process employing 2.5D braided silica fiber fabrics as reinforcements and high pure silicasol as slurry. The process parameters are optimized and the optimal parameters are as follows: the silicasol of 30.8 wt. % as slurry, microwave drying, and sintering at 900 °C. Utilizing the optimal process parameters, the density and the flexural strength of the composites can reach 1.65 g•cm-3 and 80.68 MPa respectively. Dielectric properties of the 2.5D SiO2f/SiO2 composites were also measured, and the real part of the permittivity is 3.40 at 5 GHz. The excellent mechanical and dielectric properties of the 2.5D SiO2f/SiO2 composites can well meet the requirements of radome materials.

The transmission spectra of one-dimensional (1D) photonic crystals (PCs) with parallel and twisted nematic liquid crystals (LCs) as defect layers are discussed by 4 × 4 matrix method, respectively. The results show that the photonic band gap (PBG) mainly depends on the periodic arrays of dielectric composites. The orientation of director and the symmetry of the director configuration have important influence on the location and amplitude of defect modes. The location and amplitude of defect modes can be controlled conveniently by changing the orientation of director. The symmetry of the director configuration can help us understand the defect modes spectra.

A tunable photonic crystal filter with a twisted nematic liquid crystal layer is proposed. The defect modes spectra with varying incident angles are discussed in detail by 4×4 matrix method. The results show that the defect modes are mainly decided by the applied voltage when the incident angle is smaller than 8°. As the incident angle further increases, the band gap and the defect modes shift toward the shorter wavelength side, and the changes of the two modes are different. In the lower voltage range, the defect modes can be tuned not only by the applied voltage but also by the incident angle. In the higher voltage range, the defect modes can be further tuned by varying incident angle and the different modes can be separated from each other by a big incident angle.

The ram-rotor presented by Ramgen Power Systems, Inc. is a new kind of compression system based on shock wave compression technology commonly used in supersonic intakes. Compared to conventional axial and centrifugal compressors, it has a simple and compact configuration, and also has advantages of the higher single stage pressure ratio, small volume and light weight. However, its efficiency should be further improved. Based on its inherent advantages, the ram-rotor can be widely used in small aero-engine, medium and small shipping power system, micro gas turbine employed by distributed energy system and power plant in the future. In this paper, the flow field and performance of a ram-rotor with different tip clearance sizes are simulated numerically by adopting the three dimensional Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulent model at the design condition. The purpose of numerical simulation is to investigate the flow details and performance parameters of the ram-rotor under different tip clearance sizes, including the structure of the shock wave, the size and location of flow separation zone, radial distribution of flow parameters at the outlet of the ram-rotor, the characteristics of tip clearance leakage flow, and so on. It has been found that the performance of the ram-rotor is very sensitive to the tip clearance size. The overall performance parameters of the ram-rotor decrease greatly with the increase of the tip clearance size. So, the selection of suitable tip clearance size is one of the key issues in obtaining a high performance of the ram-rotor in the design process. For the ram-rotor with tip clearance, the reflection structure of the shock wave will be destroyed. The flow loss of tip region will be increased with the increase of the tip clearance size. For the ram-rotor with and without tip clearance, the flow parameters distribution trend along the radial direction at the outlet is different.Copyright © 2014 by ASME

A tunable photonic crystal (PC) filter is proposed with the twisted nematic (TN) liquid crystal (LC) as a defect layer. The polarization sensitive performance and the eigenmodes are analyzed. The results show that there are two kinds of transmission modes, namely o and e, when the voltage is low. The different modes can be selected by rotating the filter axially. The e mode shifts toward the shorter wavelength side as the applied voltage increases. Then the peaks of two modes merge into each other and the polarization sensitive performance disappears. The photonic band gap is insensitive to the voltage. The tunable range of the filter is 53 nm.

The design methods of typical supersonic aircraft intakes and shock wave compression technology have been applied to ram-rotor, a new attractive compression system. A ram-rotor is a typical structure including the compression ramp, the throat and the subsonic diffuser; a scrampressor is similar to ram-rotor, the only different is that scrampressor has no subsonic diffuser. Base on the preparatory work, it has been found that these two structures have different advantages respectively. So, in this paper, the three dimensional Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulent model are used to simulate numerically the flow field of the ram-rotor and the scrampressor at the design and at the off-design conditions. The back pressure and rotational speed are mainly considered which may affect the flow field and the total performance. It has been found that back pressure can not have influence on the flow field before the throat outlet obviously. With increasing of the back pressure, the position of the flow separation zone and shock train move forwards to the inlet. The rotational speed changes the shock wave structure of the ram-rotor and scrampressor evidently. With the rotational speed increasing, each shock wave moves to the outlet and the shock wave number decreases. The ram-rotor and scrampressor structure is similar, except the ram-rotor flow structure has a large flow separation zone after the throat outlet. The compression capability of the ram-rotor is higher than that of the scrampressor. The total performance of the scrampressor is better than the ram-rotor.Copyright © 2012 by ASME

With the design methods of typical supersonic aircraft intakes and the advantages of shock wave compression, ram-rotors have become a new attractive compression system. Lots of research work has been carried out on rampressors, but the influence of the geometric parameters on the shock wave structure and compression performance of the ram-rotor has not been studied systematically. Therefore, a thorough study on ram-rotor with different geometric parameters is required. In this paper, a steady three-dimensional Navier-Stokes equation adopted in the “Fluent” software package is carried out on a large parallel computer. Six factors which may influence the ram-rotor performance are investigated numerically. These geometric parameters are strake section shape, throat length-height ratio, strake stagger angle, compression ramp angle, subsonic divergent angle and throat contraction ratio. The study is composed of two parts. The aim of the first part is to understand the influence of the geometric parameters listed above on the shock wave structure and compression performance of the ram-rotor by comparison and analysis of the relative Mach number and static pressure in the flow-path. The aim of the second part is to obtain the optimal geometric structure of the ram-rotor by comparison and analysis of the structure of the flow fields, the compression performance and the ram-rotor properties. First of all, the numerical method is validated by comparing the numerical results of the flow field of a supersonic intake with experimental results in this paper. Secondly, the flow field structures in the ram-rotor, especially the number and position of shock waves and the separation zone, are studied. Thirdly, the influence of the geometric parameters on the rotor performance is studied. Some parameter distributions, such as the flow angle, adiabatic efficiency, total pressure ratio, total pressure recovery coefficient, are compared and analyzed. The rules of the ram-rotor performance variation with different geometric parameters are also presented. Finally, some advice for improving the overall performance of the ram-rotor is given according to the flow field analysis.

In this paper, based on the experimental data, a detailed numerical simulation has been carried out for the compressor cascade composed of CDA blades with fences on the endwall. There are several different configurations of the endwall fences, such as length, height, and pitch-wise location for the endwall fence. The optimum lengths, height, pitch-wise or span-wise location of the fences on the cascade end walls are obtained. The process of endwall fence’s controlling secondary flow in the compressor cascade mainly lies in two ways: hindering crosswise flow from pressure surface to suction surface near the endwall of the cascade; forming and developing of fence vortex, in which the fence blockage effect is more important. Endwall fences has a significant effect on the vortices distribution, in which the formation and development of fence vortex is important. Its formation has a close relationship with the strength of the crossflow at the region between the pressure surface and fence, which is mainly due to the relative airflow movement when the pressure side branch of the horseshoe vortex rolls up and lift along the fence. For the fence vortex and passage vortex have the different rotation direction, it plays an important role in decreasing the secondary flow loss, furthermore, reducing the strength of the passage vortex. In general, stronger crosswise flow induces stronger fence vortex. As height and length of the fence increased, the blockage effect is more obvious, but the additional fence losses increased at the same time. Numerical results show that the fences, with one third of height of the inlet boundary layer thickness and the length of 75 percent axial chord, are most effective when they are located 30 percent of pitch far from the pressure surface of the blade. For all the computational cases, they reduce the cascade loss furthest respectively.Copyright © 2008 by ASME

The complexity of Peace Support Operations (PSO) requires that a wide variety of aspects and possible effects be considered. Unlike traditional analysis of combat operations, the analysis of PSO aims at avoiding conflict situations, where losses or injuries are to be minimized for all participants involved. Election scenarios in a homogeneous (Sunni) and a heterogeneous (Sunni, Shiite/Kurd) populated representative Iraqi town are developed to evaluate and gain insights on the proposed military tactics, techniques and procedures for the PSO, which may affect the outcome of the election. An agent-based modeling platform designed specifically for PSO is used to model the evolving behavior of civilian individuals and their influences on the emerging behavior of groups. An efficient experimental design, with excellent space filling and orthogonality properties, is employed to gather data from the simulation over a broad variety of scenarios. The voter participation rates, escalation among civilians, and civilian-military interactions are the primary measures of effectiveness. The results indicate that several military measures contribute to a successful election. These include the execution of security control regions, the deployment of election booths intended to calm the crowd and encourage voter participation, and attempts to quell unrest by seeking the cooperation of civilian leaders. Factors such as soldiersâ rules of engagement, civilian fear and anger personalities and their variability also play important roles in the escalation or deescalation of civilian behavior. http://archive.org/details/theeffectsofmili109451853 Approved for public release; distribution is unlimited.