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Quantification of crazing in optical components made of glassy polymers is important as crazing degrades a component’s optical performance and mechanical strength. The present work describes a single-beam-based full-field optical crazimeter for imaging and quantification of crazes in transparent samples of plastic using the principles of Fourier optics. A collimated laser beam passes through the sample and acquires information about crazes present in it. A specially designed and fabricated spatial bandpass filter is used in the 4f optical information processing setup to image crazes present in the sample and reject the noise signal. Digital image processing is used to extract quantitative information about craze density from the recorded images. The proposed crazimeter may enable full-field inspection of consumer products made of various transparent plastics for the presence of crazes.

Residual stresses are created in engineering components during fabrication and processing. Such stresses can strongly influence structural behavior. They are generally found by experimental means. A widely used way of finding residual stresses is removal of a small volume of material containing stresses and measurement of the strains that develop in surrounding material as a result of stresses being released. The strains can then be used to compute residual stresses. Drilling a small shallow hole is the most common way of implementing this approach, with strains measured by nearby strain gages adhered to the surface. This paper provides an overview of how full-field optical methods can be used instead of strain gages with hole drilling, overcoming limitations associated with gages and expanding capabilities of the hole drilling approach. The methods considered are holographic and electronic speckle pattern interferometry, Moire interferometry and digital image correlation. Advantages of using optical methods to find residual stresses are shown. A variety of applications is presented, ranging from determination of stresses in underground piping to stresses in microscale specimens. In addition, optical approaches employing different ways of material removal for stress release are reviewed, as well as several non-destructive optical methods for determining residual stresses.

To compare the observer agreement of calcification detection and assessment on synthetic mammography reconstructed to full-field digital mammograms. This retrospective study included 68 patients who undertaken screening mammogram. For each patient, FFDM and DBT were performed at Songklanakarind Hospital. Two-experienced radiologists retrospectively reviewed SM and FFDM, in separate sessions, to detect micro-calcifications and provide a BIRADS assessment. The kappa of SM and FFDM in radiologist1 in type of calcification was 0.49 (0.29-0.68), type of benign was 0.49 (0.29-0.49), type of suspicious was 0.17 (-0.06-0.42). The kappa of SM and FFDM in radiologist2 in type of calcification was 0.74 (0.61-0.87), type of benign was 0.39 (0.2-0.57), type of suspicious was 0.26 (0.11-0.4). The kappa of radiologist1 and radiologist2 of FFDM in type of calcification was 0.49 (0.29-0.68), type of benign was 0.39 (0.2-0.58), type of suspicious was 0.42 (0.24-0.59). The kappa of radiologist1 and radiologist2 of SM in type of calcification was 0.82 (0.72-0.93), type of benign was 0.49 (0.32-0.66), type of suspicious was 0.14 (0.02-0.31). In conclusion, the SM performances are similar as FFDM for detection type of calcification in diagnostic mammography screening whether the radiologist should concern about the image contrast and image reconstruction of SM.

The main goal of constitutive model calibration in the field of sheet metal forming is to describe the stress and strain relationship for numerical simulation of the production process as accurate as possible. This may be achieved through enlarged reverse-engineering strategies which are based on available classical or even modified experimental investigations. Therefore, coupon tests have to be discretised and the corresponding test setup is simulated by using the desired spatial and temporal discretisation by finite elements. In this respect the most common characterisation procedure for the identification of constitutive properties of sheet metal is the tensile test acc. to DIN EN ISO 6892-1. In this test, the measurement data such as the tension force and the specimen elongation serve as the basis for classical parameter identification. It particularly aims at identifying the yield behaviour, i.e. the yield locus and the hardening curve of the targeted sheet metal material. The goal of the present research is to investigate how the massive amount of data obtained from state-of-the-art full-field measurement via Digital Image Correlation (DIC) can be used to not only simplify the approach in constitutive parameter identification but also to automate and speed up the process in general. Furthermore, the authors believe that a more accurate description of the yield locus should be possible since the transient development of the deformation gradient is known for every measured local material point. For this purpose a concept to compare transient but scalar data from the DIC measurement with the respective data from virtual tests was developed. These so-called hyper-curves represent response curves in an optimization procedure which are evaluated at multiple locations and are extracted from simulation and experimental data. In a first step, the validation of the method which is based on synthetic (i.e. simulated) data generated with the finite element solver LS-DYNA was accomplished. The generated virtual data consists of hyper-curves with the global force as ordinate value and the local true strain in transversal and longitudinal direction as abscissae value. The results of the validation show that the target hyper-curves can be mapped almost identically and thus the parameter identification using the full-field information from simulated data has proven its applicability. Furthermore, the method was applied to data gained from an experimental tensile test of high strength steel CR210IF. To digitise the transient deformation field on the surface of the specimen a gom/aramis optical measurement system (DIC) has been used. Based on the findings of the present work, it can be stated that the proposed full-field calibration (FFC) method delivers an excellent and efficient approach for the identification of the yield curve parameters. However, the identification of yield curve parameters only shows a small range of the many possibilities that the method could provide in the future. Further constitutive parameters such as those describing the anisotropy of the yield locus, i.e. values for the exponents, Lankford parameters and such, can be identified.

One of the principle concepts to understand any hydrocarbon field is the heterogeneity scale; This becomes particularly challenging in supergiant oil fields with medium to low lateral connectivity and carbonate reservoir rocks. The main objectives of this study is to quantify the value of the heterogeneity for any well in question, and propagate it to the full reservoir. This is a quite useful specifically prior to conducting detailed water flooding or full field development studies and work, in order to be prepared for a proper design and exploitation requirements that fit with the level of heterogeneity of this formation. The main tool used for these purposes is the application of the famous Lorenz coefficient method for calculating the degree of heterogeneity for any well. The starting point for this kind of complicated studies needs to start from the basics, in order to understand the big picture and be able to plan properly for the scope to be delivered, hence, utilizing analytical tools like the ones mentioned above becomes quite necessary, if not crucial, to the success of full field modelling and choosing an optimum water flood pattern and design. This paper covers the methodology for quantifying and calculating the level of heterogeneity in a given reservoir (Majnoon Field/Hartha Reservoir) using three out of four original wells of this reservoir, and how this value impacts and directly feeds into planning for water flooding projects and selection of an optimum flood pattern. This methodology has been tested successfully in the stated super giant oil field, in which the reservoir in question is a carbonate rock formation. It is important to note that the chosen reservoir is giant areally with moderate thickness. An example of this is covered in the paper. It was concluded that utilizing a heterogeneity calculation method before conducting a detailed reservoir simulation study can save a lot of time and effort by providing guidance to the path which needs to be followed, and sheds light on the critical elements to be looked after. This has also helped to uncover many insights on the reservoir itself, hence allowing the engineer to plan for the necessary voidage replacement and water injection rates to sustain the reservoir pressure and pattern development. The suggested method, in combination with geological and petro physical information available, can be applied to majority of the reservoirs. This combination is paramount to ensure optimum time and planning is followed for each reservoir development study that involves water flooding.

One of the principle inputs to project economics and all business decisions is a realistic production forecast and a practical and achievable development plan (i.e. waterflood). Particularly this becomes challenging in supergiant oil fields with medium to low lateral connectivity. The main objectives of the Production Forecast and feasibility study for water injection are: 1- Provide an overview of the total expected production profile, expected wells potential/spare capacity, water breakthrough timing and water cut development over time 2- Highlight the requirements to maintain performance, suggest the optimum development pattern 3- Increasing confidence in business decisions to develop the reservoir in question The main tool used for these purposes is a sophisticated reservoir simulation software, namely CMG©, since it can predict reservoir behavior, honor physical constraints and capture the heterogeneity within the reservoir to accurately predict performance. However, the starting point for this kind of complicated studies needs to start from the basics, in order to understand the big picture and be able to plan properly for the scope to be delivered, hence, utilizing analytical tools like MBAL becomes quite necessary, if not crucial, to the success of full field modelling and choosing an optimum water flood pattern and design. This paper covers the methodology for building the reservoir component utilizing a Material Balance model, of which the results will be used as an input to reservoir simulation to evaluate and accurately predict reservoir performance, which directly feeds into planning for water flooding projects and selection of an optimum flood pattern. A Tank model was built at first to assess and understand the driving forces (energies) of the reservoir in question, utilizing pressure and production data from legacy wells, the prepared model is also supported by geological and petro physical studies to give representative results. Acquired Static Bottom Hole Pressures (SBHPs) in wells were used as anchor points for the tank pressure and to test the validity of the history match. Multiple analytical methods to QC the results and STOIIP volume were conducted, e.g. the Havlena-Odeh method. This methodology has been tested successfully in the stated super giant oil field, in which the reservoir in question is a carbonate rock formation. An example of this is covered in the paper. It was concluded that utilizing a history matched and coherent MBAL model before conducting a detailed reservoir simulation study can save a lot of time and effort by providing guidance to the path which needs to be followed, and sheds light on the critical elements to be looked after. This has also helped to uncover the driving mechanisms and energies in the reservoir, hence allowing the engineer to plan for the necessary voidage replacement and water injection rates to sustain the reservoir pressure and pattern development. Another technical advantage of the described method is the higher sustainability of the model. The suggested method, in combination with geological and petro physical information available, can be applied to majority of the reservoirs. This combination is paramount to ensure optimum time and planning that is followed for each reservoir development study that involves water flooding.

Photoelasticity is an effective method for evaluating the stress and its spatial variations within a stressed body. In the present study, a method to determine the stress distribution by means of phase shifting and a modified shear-difference is proposed. First, the orientation of the first principal stress and the retardation between the principal stresses are determined in the full-field through phase shifting. Then, through bicubic interpolation and derivation of a modified shear-difference method, the internal stress is calculated from the point with a free boundary along its normal direction. A method to reduce integration error in the shear difference scheme is proposed and compared to the existing methods; the integration error is reduced when using theoretical photoelastic parameters to calculate the stress component with the same points. Results show that when the value of Δx/Δy approaches one, the error is minimum, and although the interpolation error is inevitable, it has limited influence on the accuracy of the result. Finally, examples are presented for determining the stresses in a circular plate and ring subjected to diametric loading. Results show that the proposed approach provides a complete solution for determining the full-field stresses in photoelastic models.

Changes in morphology of the skin are an important factor that can affect non-invasive measurements performed through this organ, in particular for glucose monitoring in e.g. patients with diabetes mellitus. A characterization technique for non-contact in vivo profiling of the superficial skin layers can be beneficial for evaluation of the performance of such measurement systems. We applied a full-field optical coherence tomography (OCT) system followed by the fully automatic processing for this task. With the developed procedure, non-invasive quantification of the skin morphology can be performed within a few minutes. The dorsal skin of the upper arm of 22 patients with Type 1 Diabetes Mellitus was investigated with an OCT system and with a commercially available dermatological laser scanning confocal microscope (CM) as a reference method. The estimates of epidermal thickness from OCT were compared with the results of expert-assisted analysis of confocal images. The highest correlation with the CM measurements has been obtained for the distance from the entrance peak to the first minimum of the OCT reflection profile (R2 = 0.657, p < 0.0001). In this specific patient group, we have observed a statistically significant correlation of the subjects' body mass index with the distance from the entrance peak to the dermal reflection peak in the OCT profile (p = 0.010). Furthermore, the same OCT parameter is negatively correlated with age with marginal statistical significance (p = 0.062). At the same time, no relation of diabetes-related parameters (duration of disease and concentration of glycated haemoglobin) to the skin morphology observed with the OCT and CM was found.

We have developed a computer-aided detection (CAD) system to detect clustered microcalcification automatically on full-field digital mammograms (FFDMs) and a CAD system for screen-film mammograms (SFMs). The two systems used the same computer vision algorithms but their false positive (FP) classifiers were trained separately with sample images of each modality. In this study, we compared the performance of the CAD systems for detection of clustered microcalcifications on pairs of FFDM and SFM obtained from the same patient. For case-based performance evaluation, the FFDM CAD system achieved detection sensitivities of 70%, 80%, and 90% at an average FP cluster rate of 0.07, 0.16, and 0.63 per image, compared with an average FP cluster rate of 0.15, 0.38, and 2.02 per image for the SFM CAD system. The difference was statistically significant with the alternative free-response receiver operating characteristic (AFROC) analysis. When evaluated on data sets negative for microcalcification clusters, the average FP cluster rates of the FFDM CAD system were 0.04, 0.11, and 0.33 per image at detection sensitivity level of 70%, 80%, and 90%, compared with an average FP cluster rate of 0.08, 0.14, and 0.50 per image for the SFM CAD system. When evaluated for malignant cases only, the difference of the performance of the two CAD systems was not statistically significant with AFROC analysis.

To design a hybrid refractive-diffractive objective with super wide angle and fast fnumber, the interrelationship of the objective parameters was analyzed and an initial conventional spherical system was achieved to fulfill the fundamental performance, then its distortion was corrected by the aspheric surface depositing far from the optical pupil and one of doublets was replaced by hybrid refractive-diffractive lens to reduce the size of the system. Using ZEMAX software, the final visible band objective with 100° FOV and f-number 2.5 was obtained by only 6 elements with a smaller size about 35 mm×60 mm. Simulation shows that the MTF at 25 lp/mm is greater than 0.45 in the central field and 0.3 in the full field; the maximal distortion is less than 4%, much smaller than 35% of conventional system.

We study N=1,2,4 higher spin superalgebras in four dimensions and higher spin gauge theories based on them. We extend the existing minimal N=2,4 theories and find a minimal N=1 theory. Utilizing the basic structure of the minimal N=8 theory, we express the full field equations for the N=1,2,4 theories in a universal form without introducing Kleinian operators. We also use a non-minimal N=4 higher spin algebra tensored with U(3) to describe a higher spin extension of N=4 supergravity coupled to the massless vector multiplets arising in the KK spectrum of 11D supergravity on the N=3 supersymmetric AdS_4 x N^{010} background. The higher spin theory also contains a triplet of vector multiplets which may play a role in the super-Higgs effect in which N=4 is broken down to N=3., Latex, 36 pages, remarks, footnotes and references added

It is common to introduce optical tweezers using either geometric optics for large particles or the Rayleigh approximation for very small particles. These approaches are successful at conveying the key ideas behind optical tweezers in their respective regimes. However, they are insufficient for modelling particles of intermediate size and large particles with small features. For this, a full field approach provides greater insight into the mechanisms involved in trapping. The advances in computational capability over the last decade has led to better modelling and understanding of optical tweezers. Problems that were previously difficult to model computationally can now be solved using a variety of methods on modern systems. These advances in computational power allow for full field solutions to be visualised, leading to increased understanding of the fields and behaviour in various scenarios. In this paper we describe the operation of optical tweezers using full field simulations calculated using the finite difference time domain method. We use these simulations to visually illustrate various situations relevant to optical tweezers, from the basic operation of optical tweezers, to engineered particles and evanescent fields., Comment: 17 pages. 11 figures

We evaluated several amplitude reconstruction algorithms for a phase-stepped full-field optical coherence tomography (OCT), including three-, four-, and five-step algorithms, as well as a derived amplitude-based version of the Carre method, a four-step algorithm that requires equal but arbitrary step sizes that need not be known. Using a planar mirror as the sample and different phase stepping protocols, the sensitivities of the four reconstruction algorithms were measured at 85, 87, 95, and 90 dB.

The problem of calculating eddy currents and transformer signals in electromagnetic flowmeters is considered and a procedure for solving this is given. In this way Wyatt's theory (1966) relating base-line error to contact impedance effects at the electrodes is confirmed on the basis of the full field equations. A simple relation is shown to exist between the axial component Ez of the eddy current E field in the liquid and the potential U induced by a flat profile flow. Using this relation it is proved that there is no way of reducing base-line error by magnetic field shaping. The same relation between Ez and U provides the basis of a new technique for sensitivity measurement or self calibration of electromagnetic flowmeters.

Digital fringe projection profilometry is one of the most widely utilized non-contact three-dimensional (3D) profile measurement techniques. The phase error caused by nonlinear gamma of digital projectors and cameras eventually reduces the 3D measurement accuracy. This kind of phase error still cannot be detected directly at present. A novel method is present in this paper not only to measure the phase error straightforwardly but also to extract the full-field error distributions. With the aid of the detected phase error distributions, the full-field look-up tables (LUTs) can be obtained to correct the phase measurement result. A set of experiments to validate our methods has been performed. Experimental results well prove that the full-field phase error distributions have been detected successfully, and after utilizing our phase correction method the phase accuracy is obviously improved.

We realized a long-scanning-range and high-resolution interferometry in a time-domain full-field microscopic scheme by adopting a simple configuration. A reference mirror was synchronously scanned with an objective lens, which was installed in a common path, to prevent lateral resolution degradation due to defocus at the mirror. High axial resolution was obtained using a broadband supercontinuum (SC) generated by a 1.55 µm pump. The SC was generated by propagating a femtosecond pulse at 1.55 µm through a highly nonlinear dispersion shifted fiber with a small dispersion slope. We designed and constructed an interferometer carefully to utilize the entire bandwidth. The broad bandwidth of the interferometer achieved an axial resolution of 2.50 µm in air. The synchronous scanning maintained a lateral resolution longer than 1 mm. The system successfully yielded a cross-sectional image of two layers of scotch tape along the 400-µm-depth and 90-nm-step surface profiles.

We present a polarization-sensitive full-field optical coherence microscopy modality which is capable of simultaneously delivering depth resolved information on the reflectivity, optical retardation and optical axis orientation. In this way local birefringence, inherent stress–strain fields and optical anisotropies can be visualized with high resolution, as exemplified for various technical material applications.

The aberration field of an optical system with a tilted pupil is explored through expanding the vector expressions of the third-order wavefront aberrations. First, the vector forms of the wavefront aberrations are modified to obtain the aberration expressions with the pupil tilted; full field displays of coma and astigmatism in this situation are given. Then, the third-order aberration formulas with the pupil decentered and tilted simultaneously are derived and discussed. Finally, an example is taken to certify the validity of aberration distribution properties.

Full field transmission spectroscopic imaging is a powerful method for screening complex and large systems to map the distribution of valence state and electronic configuration of elements. Here, we describe an optimized hardware set-up and data evaluation tool chain for spectroscopic X-ray imaging. We tested this system successful on a ferruginous quartz (SiO2) sample.

A full-field optical technique capable of measuring angular deflections of light rays reflected off specularly reflective planar surfaces is developed. The method is aided by 2D digital image correlation to measure angular deflection of light rays. The principle of the method is described and the governing equations that relate light ray deflections to surface slopes are presented. The method is demonstrated by measuring the orthogonal surface slopes of a circumferentially clamped silicon wafer subjected to a central load and are shown to be in good agreement with the analytical solutions. The curvature fields are also computed by taking advantage of differentiation schemes integral to digital image correlation algorithms. The method is utilized to successfully quantify relatively small surface slopes of the order of 10−5 rad caused by a curing layer of spin-coated epoxy on a thin (100 µm) silicon wafer.

ITER as a superconducting fusion machine needs efficient wall conditioning techniques for application in the presence of the permanent high toroidal magnetic field for (i) reducing the in-vessel impurity content, (ii) controlling the surface hydrogen isotopic ratio and (iii) mitigating the in-vessel long-term tritium inventory build-up. Encouraging results recently obtained with ion-cyclotron wall conditioning (ICWC) in the present-day tokamaks and stellarators have raised ICWC to the status of one of the most promising techniques available to ITER for routine inter-pulse and overnight conditioning with the ITER main ICRF heating system in the presence of the permanent high toroidal magnetic field. This paper is dedicated to a milestone experiment in ICWC research: the first simulation of ICWC operation in an equivalent ITER full-field scenario and the assessment of the wall conditioning effect on the carbon wall in the largest present-day tokamak JET. In addition, we address in this paper the following topics: (i) an analysis of the radio frequency (RF) physics of ICWC discharges, (ii) the optimization of the operation of ICRF antennas for plasma startup and (iii) an outlook for the performance of ICWC in ITER using the ICRF heating system. Important operational aspects of the conventional ICRF heating system in JET (the so-called A2 antenna system) for use in the ICWC mode are highlighted: (i) the ability of the antenna to ignite the cleaning discharge safely and reliably in different gases, (ii) the capacity of the antennas to couple a large fraction of the RF generator power (>50%) to low-density (≈1016–1018 m−3) plasmas and (iii) the ICRF absorption schemes aimed at improved RF plasma homogeneity and enhanced conditioning effect. Successful optimization of the JET-ICWC discharge parameters (BT = 3.3 T, f = 25 MHz) resulted in a reliable operation of the JET A2 antennas and a high conditioning efficiency in a scenario imitating closely ITER full-field operation (BT = 5.3 T, f = 40 MHz) with the fundamental ion-cyclotron resonance for deuterium located on-axis. Numerical modelling with the 3D electromagnetic code Micro Wave Studio, a 1D RF full wave code and a 0D plasma code allows extrapolating the results obtained on JET and other present-day tokamaks to ITER and provides good prospects for the use of the ITER ICRF antennas for ICWC purposes.

We demonstrate tomographic and volumetric reconstruction of composite material using a full-field swept-source optical coherence tomographic (FF-SS-OCT) system. The FF-SS-OCT system is based on a co-axial and common-path optical interferometric system based on Mirau objective lens. By means of sweeping the frequency of the broad-band light source, multiple spectral interferograms are recorded and stacked in the X–Y–λ axes and processed in a computer. Optically sectioned images of the composite material at different depths are reconstructed. From the spectral interference fringe signal, the phase maps at various depths are also reconstructed. Due to its common path configuration, the present FF-SS-OCT system is highly stable and less sensitive to external vibration and does not require lateral B-scan leading to a large area measurement of the sample.

This paper presents a methodology aimed at the identification of the mechanical behaviour of hyperelastic low density polymeric foams using digital image correlation and the Virtual Fields Method. First, a simple bending/shear test enables the identification of the elastic parameters at low strain levels. Then, a uniaxial compression test is performed to identify the parameters of an Ogden-type law (hyperelastic). The strain fields exhibit strong localization caused by the elastic collapse of the cells clearly indicating that an approach based on global force/displacement curves will fail to provide intrinsic material parameters (structural effect). This is still very much a preliminary study but it clearly shows the potential of the approach for this type of materials.

A method for determining stress components from a single image is proposed in two-dimensional interferometric photoelasticity. A two-dimensional birefringent specimen placed in a Mach–Zehnder interferometer is observed using a CCD camera equipped with a pixelated micro-retarder array. The light emerging from the Mach–Zehnder interferometer contains the information of the difference and the sum of principal stresses, and the principal direction. The distribution of the Stokes parameters of the light vector is determined from a single image since the CCD camera with a micro-retarder array can instantaneously record multiple pieces of information. Then, the distribution of the stress components can be evaluated from the Stokes parameters. It is expected that this method can be applied to time-varying phenomena since multiple exposures are not necessary for the completion of stress components analysis.

A full field X-ray microdiffraction technique is developed providing simultaneously both micrometer-resolved information of crystalline perfection as well as statistical information about the macroscopically illuminated sample. The method allows a detailed characterization of patterned substrates grown by epitaxial lateral overgrowth. Local wing tilts and their fluctuation over the sample area as well as the local and average number of grains in the wings are determined, and the reduction of threading dislocation densities in the grains of the ELO wings can be quantitatively estimated.

A full-field optical coherence tomography (OCT) system that can control longitudinal resolution is presented. The system is based on the synthesis of the optical coherence function from the wavelength scanning of laser light within a frame time of an imaging device. On the basis of the results of our experiments, it is confirmed that our system can select any longitudinal resolution between 6–120 µm and that this performance is available for practical use such as for the tomographic imaging of various sizes of targets in a scattering medium.

We describe a simple modification to the Senarmont compensator which makes it possible to use it for measurements over a wide range of wavelengths.

For pt.III see ibid., vol.10, p.959 (1977). The effects of magnetic field inhomogeneities and the motion of the spins on Zeeman resonance lines are examined for a simple system of non-interacting spins contained in a sphere. The values of the field strength parameter Delta and the relaxation time tau , which in the combination eta = Delta tau characterize the lineshapes, are calculated exactly. In the absence of motion (1<< eta ) the lineshapes are easy to evaluate and depend on the full field inhomogeneity. In the opposite limit of motional narrowing ( eta <

Six lenses have been designed with the aid of an automatic correcting program. The lenses were designed to the following specifications: focal length 24 inches, f-number 6.0, full field format 9×9 inches square. Two lenses were triplets, two were four element lenses, one was a triplet with four aspheric surfaces and one used five elements. The four element lenses appear to have the best performance.