Wedge Parameters Research Articles

Unsteady magnetohydrodynamic tri-hybrid nanofluid flow past a moving wedge with viscous dissipation and Joule heating

This study aims to boost thermal convection through careful selection and adjustment of nanomaterial volumes, focusing on the unsteady magnetohydrodynamic flow past a moving wedge with viscous dissipation and Ohmic heating in a ternary nanofluid of alumina (Al2O3), copper oxide (CuO), and copper (Cu) in water. Employing mathematical modeling and numerical analysis via MATLAB's BVP4C, it explores how discharge concentration influences flow characteristics and identifies critical conditions for single or dual solutions. Key parameters such as motion and wedge parameters, Eckert number, magnetic strength, and nanoparticle volume ratios were scrutinized for their impact on fluid dynamics and heat transfer. Results show enhanced convective thermal transfer with increased nanoparticle hybridity and volume fraction, alongside suction/injection parameter (S), unsteadiness parameter (A), Eckert number (Ec), and magnetic parameter (M), albeit decreasing with wedge angle adjustments. Stability analysis revealed the stability of the initial solution vs the instability of the secondary. Introducing a novel time variable, τ=cAt(1−ct), this research demonstrates that at λ=−4.7(a leftward wedge) with a 0.04 nanoparticle volume fraction, ternary and hybrid nanofluids significantly outperform mono nanofluid, achieving thermal efficiency gains of 25.6% and 7.5%, respectively. This foundation underscores the potential of optimized nanofluid mixtures for advanced heat transfer applications.

ГРАФО-АНАЛИТИЧЕСКИЙ МЕТОД ОПРЕДЕЛЕНИЯ НАПРЯЖЕНИЙ В ПОЧВЕННОМ СЛОЕ ПОД ДЕЙСТВИЕМ ДВУГРАННОГО КЛИНА

The study of the stress distribution process in the soil layer is an important stage in the design of tillage machines, particularly tillage working elements. The experimental identification of patterns between the stress distribution zone in the soil layer and the parameters of tillage working elements is a time-consuming process. Therefore, it is recommended to conduct preliminary mathematical modeling of this process to minimize the overall number of experiments. The research purpose: development of a grapho-analytical method that can determine the pattern between the stress distribution zone in front of the dihedral wedge and its parameters. The concepts of classical and agricultural mechanics were used in the research. The methodology is based on scientific methods of cognition such as mathematical modeling, abstraction, analysis, and synthesis. Using the equation proposed by J. Boussinesq, a grapho-analytical method was developed to determine the stresses arising in the soil layer under the influence of the dihedral wedge. This method takes into account the influence of the dihedral wedge parameters and the physical and mechanical characteristics of the soil. The proposed method can be used in the design of tillage working elements. Specifically, to justify the chisel outreach of the blade working element at the stage of theoretical research. It was found that there is a direct proportion between the length of the dihedral wedge and the total area of deformed soil. Thus, as the length of the wedge increased by 83 percent (from 0.05 to 0.30 meters), the area of deformed soil increased by 80 percent (from 0.02 to 0.10 square meters).

FMC/TFM Technique Design Using the FMC Beamset in BeamTool

Eclipse Scientific’s BeamTool software has supported Full Matrix Capture/Total Focusing Method (FMC/TFM) technique design through the FMC Beamset since version 9.0 (released in 2017). With the release of BeamTool 10.1, however, the FMC Beamset now includes more sophisticated tooling to help users design FMC/TFM based inspection techniques – these include: Sensitivity, Focal Area and Resolution maps which together allow users to quickly assess how similar reflectors will be imaged (amplitude, shape, size) throughout the chosen region of interest. For each of these focal metrics, the absolute minimum and maximum values are provided along with other helpful derived quantities (amplitude fidelity, maximum sensitivity difference) which allows the influence of probe and wedge parameters to be compared directly. This document details what these new focal metrics are as well as how to use them to optimize FMC/TFM based techniques for various common applications. It is assumed that the reader is familiar with the principles of FMC/TFM and the BeamTool software.

Mechanical Performance Analysis of Hydrostatic Thrust Bearing under Microbevel Parameters

Background: Heavy-duty hydrostatic bearings of the original parallel friction pair are prone to hydrostatic loss problems during operation. Aims: To solve the failure problem, the original hydrostatic oil pad was designed as a micro-inclined plane, and the dynamic pressure caused by the micro-wedge of the oil pad at a higher speed was used to compensate for the static pressure loss of the bearing. objective: For a new type q1-205 microbevel double rectangular cavity hydrostatic bearing. Objective: This study aims to design a new type of q1-205 micro bevel double rectangular cavity hydrostatic bearing. Method: The mathematical model of oil film theoretical analysis of hydrostatic bearing with the micro-inclined surface was established, including the flow equation of a double rectangular cavity with a micro-inclined surface and static and dynamic bearing capacity equation. result: The oil film lubrication performance of the bearing with the wedge parameters of 0mm, 0.02mm, 0.04mm, 0.06mm, 0.08mm and 0.10mm was simulated by the finite volume method, the comprehensive influence law of the wedge-shaped parameters on the vorticity and flow rate of the oil cavity pressure fluid was revealed. Finally, the oil cavity pressure changes of oil films with different wedge parameters under certain load and speed were tested by design experiments, and the theoretical analysis and simulation were verified. Result: In this paper, the mechanical properties of oil film with tilt height between 0 and 0.1mm were simulated with variable viscosity, and the distribution law of pressure field under different working conditions was obtained. Through the experimental study, the pressure data of parallel flat pads and tilting pads under different working conditions are measured and compared with the simulation data. Conclusion: The pressure loss value of the oil pad designed in this paper is relatively small under extreme working conditions. The overall loss rate is about 10% ~ 20%, and the dynamic pressure compensation rate is about 16%. The dynamic pressure generated by the slight inclination Angle can well compensate for the static pressure loss.

Effect of microbevel parameters on lubrication performance of heavy-duty hydrostatic thrust bearing

PurposeTo solve the problem of oil film thinning when hydrostatic thrust bearings are overloaded or rotating at high speed, the dynamic pressure formed by tiny oil wedges is used to compensate, and the optimum height of oil wedges is determined by the compensation rate to improve the bearing capacity of hydrostatic thrust bearings.Design/methodology/approachThis research method is aimed at the new type of double rectangular cavity static bearing with microbevel surface of q1-205. The wedge parameters of oil film were defined. The oil film lubrication performance of the bearing with the wedge parameters of 0, 0.02, 0.04, 0.06, 0.08 and 0.10 mm was simulated by the finite volume method, the comprehensive influence law of the wedge-shaped parameters on the vorticity and flow rate of the oil cavity pressure fluid was revealed. Finally, the oil cavity pressure changes of oil films with different wedge parameters under certain load and speed were tested by design experiments, and the theoretical analysis and simulation were verified.FindingsThis study found that the oil film wedge shape can well compensate the static pressure loss caused by the high-speed or heavy-duty operation of the bearing, but the dynamic pressure effect of the wedge shape does not always increase with the increase of the wedge height. The oil film exhibits superior lubrication performance in the range of 0.06–0.08 mm.Originality/valueThe original hydrostatic oil pad was designed as a microinclined plane, and the dynamic pressure caused by the microwedge of the oil pad was used to compensate the static pressure loss of the bearing. The lubrication performance of the oil film under the condition of varying viscosity was obtained by using the simulation method.

Quantification of localised vascular wedge-shaped defects in glaucoma.

Vascular dysfunction plays a considerable role in glaucoma pathogenesis. Previous glaucoma case studies described localised wedge-shaped vascular defects, similar to retinal nerve fibre layer (RNFL) wedge defects. This study investigates the prevalence and quantification of this vessel loss, in relation to primary open angle glaucoma (POAG) parameters. This study included 608 eyes (351 participants): 192 PROGRESSA study participants (342 eyes) with suspect, preperimetric or early manifest POAG, observed for vascular wedge defect presence (cohort one); an additional 114 individuals (cohort two-208 eyes) with POAG at various stages of progression for wedge characterisation; and 38 controls (56 eyes). Vascular wedge defects were observed using optical coherence tomography angiography (OCTA). Wedge parameters and vessel densities were quantified using ImageJ software. RNFL and ganglion cell layer inner plexiform layer (GCLIPL) from OCT scans, and mean deviation (Humphrey visual field 24-2) were also assessed. Vascular wedge defects were found in 45/342 eyes (13.2%) in cohort one, in 41/208 eyes (19.7%) in cohort two and were not found in controls. Wedge defects were mostly inferotemporal (80%), and present at all disease stages. They were associated with visual field loss in the opposite hemisphere, thinner RNFL (p < 0.001), thinner GCLIPL (p=0.003), and focal RNFL loss corresponding with the vascular defect region. Vascular wedge defects are present at all POAG stages even before functional change and are strongly concordant with focal RNFL loss. Further research is needed to explore these defects in particular their temporal relationship with clinical measures of POAG.

Analysis of boundary layer nanofluid flow over a stretching permeable wedge-shaped surface with magnetic effect

The problem of steady two-dimensional boundary layer flow of momentum, heat and mass transfer over a stretching permeable wedge-shaped surface in a nanofluid in presence of magnetic field has been studied. In this respect, the governing partial differential equations have been converted into ordinary differential equations by using the local similarity transformation. The transformed governing equations have been then solved numerically using the bvp4c in MATLAB software. The effects of the pertinent parameters, namely wedge angle parameter (β), Brownian motion (Nb), thermophoresis (Nt), magnetic parameter (M), moving wedge parameter (λ), permeability parameter (K*), Prandtl number (Pr), and Lewis number (Le) on fluid velocity, thermal and concentration within the boundary layer have been analyzed. The numerical results obtained of the skin friction coefficients, local Nusselt number and local Sherwood number, as well as the velocity, temperature and concentration profiles have been presented graphically and also in tabular form. The results indicate that the momentum boundary layer thickness increases with increasing values of wedge angle and moving wedge but reduces for magnetic and permeability effects. The heat transfer rate increases for wedge angle, moving wedge, Brownian motion but decreases for thermoporesis and magnetic effects. The mass transfer rate decreases for Brownian motion and thermoporesis effects but increases for wedge angle and moving wedge parameters. Finally, the numerical results have been compared with previously published research and found to be in good agreement.

Determination of bench, dump and road sliding wedge technological parameters

Mine surveying in mining operations is of particular importance, since all technological processes of the full life cycle of a mining enterprise and, ultimately, its competitiveness depend on the surveying quality, efficiency and reliability. Organizations independently determine the structure of mine surveying services, taking into account the methods applied and the scale of mining. To ensure safe open-pit mining of minerals, it is necessary to permanently assess and monitor the pit bench and wall rock mass condition. Misjudgement of rock physical and mechanical properties, non-observance of the minerals mining and transportation process cycle, changes in climatic conditions and other problems lead to loss of stability of rocks in all parts of an open pit, including in the areas of ore production and mining and transport equipment operation. The existing practice shows that the effectiveness of an open pit wall and bench stability calculation can be achieved using a technique that should take into account the slope deformation and failure mechanism, as well as the nature of the stress-strain state of the open pit rock mass. The studies presented in the paper are based on comparative analysis of the sliding wedge parameters for benches, dumps and roads at open pits using analytical and graphical software packages, and taking into account the static load produced by dump trucks. The study findings allow to establish that: determination of the bench slope stability and the sliding wedge width, performed by the analytical method, gives higher accuracy results than those obtained by the graphical method; the bench slope stability and the sliding wedge width depend not only on the rock physical and mechanical condition, but also on the bench height, the dump truck (plus its freight load) weight per 1 linear meter of the placement area, the distance from the slope edge and other factors; the rock mass is stable and not subject to landslide phenomena for as long as the sum of the holding forces is greater than or equal to the sum of the shearing forces; when using large-sized transport equipment of nonstandard weight in open-pit mining, it is necessary to calculate the safe width of the sliding wedges, taking into account the loads on them (per 1 linear meter), the values of which can be 1.5–2.0 times higher than those calculated for the circular-cylindrical sliding surface.

Heavy load characteristics of micro-beveled heavy-duty hydrostatic bearing lubricant oil film

This paper is based on the new Q1-205 micro-beveled double rectangular cavity heavy hydrostatic thrust bearing. According to the hydrostatic and dynamic pressure lubrication theory, the mathematical model of the dynamic and static bearing capacity of micro-beveled oil film is established under the conditions of considering the bearing oil supply system and the actual structural of the oil pad. Based on the finite volume method, the lubricating performance of the oil film is numerically simulated under heavy load of 10t, 15t, 20t, 25t and 30t, and the comprehensive influence law of oil cavity pressure, fluid velocity, vorticity and flow rate is revealed under the influence of extreme working conditions such as heavy load. Finally, the oil film pressure field affected by heavy load is tested under certain wedge parameters and rotational speed and verifies the theoretical analysis and simulation. It is found that the experimental and theoretical result of bearing is consistent with each other under heavy load. The dynamic pressure compensation effect of the bearing is better under the wedge oil pad condition. However, under heavy load, the extrusion and heating of lubricating oil are serious, which make the viscosity of lubricating oil drops sharply. In addition, the dynamic pressure effect of wedge oil pad is less affected by load. The compensation effect decreases slightly with the increase of load. The dynamic pressure compensation range of the bearing is 30%–10% under heavy load.

Inspection of butt welds for complex surface parts using ultrasonic phased array

Detection of weld defects for complex surface parts has always been a difficult point in ultrasonic testing because the geometry complexity makes it difficult to arrange transducers and determine the propagation paths of acoustic beams. In this paper, the linear friction weld of the engine blade is taken as an example of the butt weld in complex surface parts, and the application of the ultrasonic array testing method is carried out. Firstly, the propagation properties of acoustic waves in the inspection area are analysed based on both the Snell's law and the acoustic pressure reciprocating transmittance (APRT). According to the inspection requirements, this study establishes a full-coverage inspection solution using multi-array transducers. Secondly, the whole inspection area is divided and the wedge parameters in each subarea are iteratively designed. Thirdly, based on the finite element method (FEM), a response simulation model of the ultrasonic array is established to testify the feasibility and validity of the inspection scheme. Lastly, experiments are conducted on the blade specimen welded by linear friction welding (LFW). The inspection results of different weld positions clearly identify the prefabricated crack defects, showing that the proposed method can fulfill the rapid and accurate inspection for the butt weld of complex surface parts.

A probabilistic method for evaluating wedge stability based on blind data theory

This study proposes a probabilistic approach based on blind data theory and a k-means clustering algorithm to analyze the wedge stability problem considering multiple failure modes. The method evaluates the stability of the wedge by constructing a blind data model that can comprehensively consider the various uncertainties of the wedge parameters. The construction of the blind data evaluation model of wedge stability is described, and the blind evaluation model used to determine the wedge stability with wedge failure dominated by a prone-sliding face and double-face failure is given. The model is applied to analyze the stability of a classical double-face wedge. The results are compared with the probability of failure evaluated by a Monte-Carlo simulation, as well as the results obtained from deterministic analysis, including the mean safety factor and SWEDGE numerical analysis methods. The probability distribution for the safety factor of the wedge determined by this method is fairly consistent with those from the Monte-Carlo simulation method, verifying the reliability and efficiency of the new method. Finally, the method is applied to the stability evaluation of the wedge in Huludao city, Liaoning Province, China. The probability of safety factors less than 1 is 89.8%, and the probability that the safety factor is less than 1.2 is 100%, which is consistent with the actual situation. This result demonstrates that the blind data model for evaluating wedge stability exhibits good generalization performance.

EFFECT OF DIMPLE GEOMETRIC PARAMETERS OBTAINED ON METAL SURFACE BY ELECTRICAL DISCHARGE ON ITS CUTTING ABILITY

The paper contains an analysis of dimple geometric parameters obtained on wire surface during its in its electrical discharge machining. A photography and description of one of the dimples has been given in the paper. The paper has analyzed a cross-sectional shape of the obtained dimple with due account of the solidified metal flows formed along its edges. The flows in a first approximation can be considered as elements of a cutting wedge. According to cutting theory provisions the paper considers solidified metal flow shapes in a longitudinal section and indicates angles which have been formed by the flows, working planes and edges which can be involved in the cutting process. It has been shown that cutting elements on the dimple surface are arranged symmetrically that makes it possible to carry out cutting process while moving a tool in both directions of reciprocating motion. Parameters of cutting surface influencing on cutting process execution have been specified in the paper. It has been demonstrated that due to changes in energy of electric discharge through voltage or capacity of a power supply storage capacitor it is possible purposefully to influence on the shape and size of metal flows and, respectively, on values of cutting wedge parameters that characterize a tool cutting ability. A conclusion has been made about possibility to obtain the most advantageous values of these parameters while optimizing modes of wire electrical discharge machining.

Heat Transfer Analysis of MHD Water Functionalized Carbon Nanotube Flow over a Static/Moving Wedge

The MHD flow and heat transfer from water functionalized CNTs over a static/moving wedge are studied numerically. Thermal conductivity and viscosity of both single and multiple wall carbon nanotubes (CNTs) within a base fluid (water) of similar volume are investigated to determine the impact of these properties on thermofluid performance. The governing partial differential equations are converted into nonlinear, ordinary, and coupled differential equations and are solved using an implicit finite difference method with quasi‐linearization techniques. The effects of volume fraction of CNTs and magnetic and wedge parameters are investigated and presented graphically. The numerical results are compared with the published data and are found to be in good agreement. It is shown that the magnetic field reduces boundary layer thickness and increases skin friction and Nusselt numbers. Due to higher density and thermal conductivity, SWCNTs offer higher skin friction and Nusselt numbers.

Determination of wear pattern of cutting elements of tillage machines

The problems of theoretical researches of wear surface of the working tools’ cutting elements of tilling machines are shown in the article. The main aim of the research is to develop a process of hardening, providing increase their longevity and quality of soil treatment. The interaction process of working tools of tilling machines with soil abrasive environment during their movement is characterized by the interaction of abrasive soil on wedge with a flat working surface. This article describes how to influence the impact of soil on a wedge from material deformation nature, the wedge parameters, physical and mechanical properties and soil conditions. The theoretical dependence of these parameters allows to provide the wear of the cutting elements of tilling machines, which will contribute to reduction of the dynamics of their wear. To ensure the longevity of cultivator tooth is necessary reducing the size of their wear is necessary to reduce the ability of abrasive wear out and will provide options of cultivator tooth, which will reduce the dynamics of wear. The research results will select and apply an effective technology of hardening of cutting elements of tilling machines during wear and recovery.

Improving the electrostatic field concentration in a negative‐permittivity wedge with a grounded “bowtie” configuration

Two wedges, one made of negative‐permittivity material (primary) and another of an ordinary dielectric (auxiliary/secondary), are posed nose‐to‐nose to form a “bowtie” configuration. This shape is very common and convenient for a number of real‐world devices and constructions such as electron microscopes, optical superlenses, and nanotips. In all these structures, the efficient operation and functionality get strongly assisted by the increased electromagnetic power concentration in the vicinity of the edge. Such a field enhancement is attempted with proper choice of the characteristics of the dielectric wedge to increase the field intensity over the cross section of the metamaterial one. A slowly varying field assumption is adopted to formulate approximate solutions to similar structures (sharp and rounded corners). A quality factor has been defined based on the power carried by the supported modal waves, if they are excited by a suitable electric source, in the presence and in the absence of the auxiliary wedge. This quantity expresses the intensity enhancement that could be achieved and is represented in graphs with respect to the dielectric wedge parameters. The characteristics of the secondary component that lead to a maximization of the electric power into the primary one are identified and explained. In particular, periodic variations of the angular extent of the secondary wedge are observed, and the number of maxima is increased with the dielectric permittivity of the constituent material.

Study of Strain Wedge Parameters for Laterally Loaded Piles

Asetofsmall-scalephysicalmodelingofasinglepileunderlateralloadswasperformedinaloosesandenvironment.Digitalimages were captured during the lateral loading of the pile from the side and from the top of the model simultaneously. The particle image velocimetry (PIV)methodwasapplied,andthedeformationsofthesoilaroundthepileandthesoilstrainswereobtainedfromthesetests.Thesoildisplace- ment patternnearthesurfacearoundthepiles wasstudied,andtheeffectofthepilelengthonthesoildeformation patternwasinvestigated. The effectofpilestiffnessandwidthonsoildeformationpatternswasalsostudied.Forthestudyofsoildeformationpatternsaroundrigidpiles,three tests with rigid piles were undertaken, and strain distribution in the soil was obtained. Based on PIV analysis, a three-dimensional strain wedge with the shape of a circular cone was formulated. The equation of the strain wedge was derived, and with the stress-strain limit equilibrium analysis, the lateral load response of the pile was obtained. Lateral load capacities of several piles from different studies were estimated based on various pile and soil properties, and these results are compared with the measured capacities. Comparisons show good agreement with the load measurements. DOI: 10.1061/(ASCE)GM.1943-5622.0000186. © 2013 American Society of Civil Engineers. CE Database subject headings: Piles; Lateral loads; Soil deformation; Strain; Parameters. Author keywords: Flexible piles; Lateral loading; Particle image velocimetry (PIV); Soil deformation pattern; Strain wedge.

SU-FF-T-630: Characterizing the Enhance Dynamic Wedge Parameters in the Eclipse Treatment Planning System and Assessing Its Accuracy in Beam Modeling

Purpose: The purpose of this study is to assess the accuracy of Eclipse treatment planning system in modeling Clinac EDW beams and to evaluate the effect of the three EDW parameters on its outcome. Method and Materials: The wedge factors(WFs) were measured in symmetric fields from 4×4 cm2 to 20×20cm2 and asymmetric fields to the maximum of 30×(20,10). Point of measurement was in solid phantom at 10cm depth and 100cm SSD setup using a PR06 ion chamber. Measured and calculated data for the standard set of wedge angles with 6, 10 and 23 MV photon beams by comparing the WFs. Effects of the three parameters were monitored by the MU changes. Results: The calculated WFs have more discrepancies on large wedge angles and field sizes and tend to be lower than the measured value. All parameters had minimal to no effect on 4×4cm2 fields. For field size ⩾10×10cm2, the deviations were less than 2% after the adjustment. Increasing the secondary source size will increase the MU and is more sensitive on the medium field sizes. It will take a minimum of 2mm change before any effect can be observed. Increasing the relative intensity will decrease the MU and the effect is more sensitive on 60° wedges. Increasing the mean energy increases the MU and the effect is greater for larger field size and wedge angle. Conclusions: There are limitations in utilizing the EDW parameters for modeling all field sizes and wedge angles to within 2% deviation from measured value. User has to compromise between the smallest field size and largest wedge angle. Best is to start with relative intensity to minimize deviation among wedge angles and field sizes before adjusting the second source size parameter to fine‐tune the MU between wedge angles.

Dynamic wedges – dosimetry and quality control

Summary Background Modern medical accelerators are usually equipped with a dynamic wedge option. It is a form of dose-rate modulation which makes use of the dynamic movement pairs of collimator jaws. Dynamic wedges may replace physical wedges but their use requires more complex dosimetry and quality control procedures. Film dosimetry has been proposed as a quality control tool in dynamic dose distribution. We present examples of extensive systematic calculation errors which were detected during complex dosimetry quality control procedures in two treatment planning systems. Aim The aim, in presenting QA procedures and examples of systematic errors which were detected and corrected, is to focus attention on the QA of dynamic accessories used in TPS before they are used in the clinical practice. This is an important issue which may have been frequently overlooked as the configuration of dynamic wedges in many treatment planning systems requires no dose measurement data. Measurements of verifications are often, overlooked. Materials/Methods Dynamic wedge dose distributions were generated by Clinac 2300 C/D accelerators (Varian) for beam energies of 6 and 15 MV. Measurements were performed with LA48 linear array of ionization chambers (PTW), and with dosimetric films X-Omat V and EDR-2 (Kodak). The dosimetric characteristics of the film were examined for a wide range of dose values and beam parameters. The results of the measurements were compared with dose distribution calculations produced by the treatment planning systems Helax and CadPlan/Eclipse. Results The initial results showed considerable differences between measurements and calculations. Larger differences were observed for larger wedge angles and lower energies. On the basis of these results, TPS manufacturers were able to tune their calculation algorithms which effectively reduced the observed differences from a level of −5.5% and −8% (for 15 and 6 MV respectively) for 60° wedges to a level of ±2% for the Helax system. Conclusions A comprehensive quality control procedure for a broad range of dynamic wedge parameters, on a Clinac 2300C/D, made it possible to achieve an improved agreement between measured and calculated results in radiotherapy. Such measurement procedures should be included in the recommendations for periodic quality control tests of accelerators.

Improvements of Edges Diffraction Computing in GRECO

Graphical Electromagnetic Computing (GRECO) is one of the valuable methods for computing the radar cross section (RCS) of complex radar target in high frequency region. But there are some shortages of wedge detecting method in the original GRECO literature. A new method for collecting the edge pixels and wedge parameters is presented in this paper. An expression of edge diffraction field in the original GRECO literature is in error, the error-corrected formulas are derived by using method of equivalent edge currents (MEC) and physical theory of diffraction (PTD). Finally, the total RCS expression is given by physical optics (PO) and PTD method. The computing results are in close agreement with the measured data.

Fourier analysis applied to the characterization of optical wedges with small angles

A technique for the measurement of optical wedge parameters is shown. It is based on the analysis of the Fourier transform of an interferogram-intensity register. In this domain the angle and the edge orientations of the optical wedge can be determined through a much simpler procedure than the usual interferogram fringe analysis.