Orientation Angle Research Articles

Hydrothermal performance of a heat sink using Plate-fins: Experimental and numerical investigations

The development of electronic devices is accompanied by the generation of significant heat. A novel plate-fins design with various orientation angles of 30°, 35°, 37.5°, 40° and 45° was studied. The plate-fins design aims to boost the performance by increasing the surface area and redirecting airflow towards the heat sink plate. The experimental results obtained by this work were employed to validate the numerical results for pin-fins heat sink. A three-dimensional computational domain was investigated using ANSYS Fluent 19.1. The air flow was turbulent and modelled using k-ω turbulent flow. The plate-fins with an orientation angle of 37.5ᴼ exhibit the optimum hydrothermal performance among other configurations. Equally, several optimisation parameters including the number of rows, the diameter and thickness of the pins and the width of the plate-fins were investigated. It was observed that the heat sink with two rows of plate-fins outperformed other designs. This configuration resulted in a significant reduction of 2 % in hot spot temperature and a notable reduction of 60.8 % in pressure drop.

Knee valgus deformity: indications and outcomes for a high tibial medial closing-wedge osteotomy

IntroductionTraditionally, knee valgus deformities have been corrected through distal femur osteotomies. The advances in preoperative planning allow surgeons to understand the leading site of deformity better and, therefore, propose corrections at the appropriate anatomical location. ObjectivesThe purpose of this evaluation is to present a case of a knee valgus deformity where most of the deformity resulted from the joint and the proximal tibia. A medial closing wedge tibial osteotomy corrected the proximal tibia deformity, while a fresh osteochondral allograft aimed to improve the surface of the lateral compartment of the knee, optimizing the joint lateral convergence angle. In addition, indications, outcomes and a scoping review of the literature for closing wedge high tibial osteotomy for knee valgus deformity is reviewed. MethodsA clinical case report example of a patient with knee valgus deformity requiring closing wedge high tibial osteotomy is presented. Detailed discussion of preoperative templating, planning and surgical completion is reviewed. A systematic review of previous studies and outcomes after closing wedge high tibial osteotomy was undertaken and summarized. ResultsThe case presented demonstrates an example of a valgus knee deformity with alignment correction vis a proximal tibial ostetomy. A review of and summary of previous case reports and outcomes studies for similar pathology demonstrates a high degree of success for this surgical approach. ConclusionsClosing wedge high tibial osteotomy is a viable treatment option for knee valgus deformity with an abnormal mechanical medial proximal tibial angle (mMPTA). A thorough evaluation of joint orientation angles is necessary to appropriately address limb deformity at the specific locations(s) of significant anatomic abnormality.

Dynamic Effect of Ply Angle and Fiber Orientation on Composite Plates

Composite materials have revolutionized industries such as aerospace and automotive with their impressive strength-to-weight ratios and customizable properties. Ply angle and fiber orientation are critical factors that significantly impact the dynamic behavior of composite structures, influencing stiffness, strength, and vibrational characteristics. This research delves into the dynamic characteristics of composite plates, explicitly examining how ply angle and fiber orientation affect vibrational behavior. Through finite element analysis (FEA), composite plates with varying ply angles and fiber orientations were modeled to understand their influence on natural frequencies, mode shapes, and dynamic responses under various loading conditions. The study reveals that cross-ply [0/0/0/0] exhibits the highest stiffness and superior stress handling, while the cross-ply balanced laminate [90/0/0/90] demonstrates better vibrational characteristics. The findings highlight the intricate relationships between design parameters and structural vibrational behavior, offering opportunities for optimizing composite structures. Additionally, harmonic analysis showed that a cut-out increases the natural frequency. The results underscore the importance of optimizing composite plate configurations to enhance vibrational characteristics and align natural frequencies with operational requirements, thereby mitigating resonance-related issues.

Numerical investigation for shear behavior of pretensioned spun precast concrete pile

Pretensioned spun precast concrete (SPC) pile has emerged as a popular solution for deep foundation systems due to its ease of construction, enhanced bearing capacity, and overall cost-effectiveness. However, the hollowness of SPC piles, which reduces their sectional area, may become critical near the pile cap zone, especially in liquefaction scenarios during earthquake events. This study numerically investigates the shear behavior of hollow pre-tensioned SPC piles using the Finite Element (FE) technique. Primarily, the numerical results are validated with the test results of actual SPC piles where they were manufactured by high-strength concrete and high-tensioned steel strands for both with and without spirals. The numerical results show a good agreement with the experimental data in terms of strength, stiffness, and failure pattern for both types of spiral arrangements. The numerically obtained shear capacity is also found to be within close range of the code recommendations. A series of parametric studies have been conducted to understand the influence of essential pile parameters such as spiral’s spacing, effective prestress, number of strands, thickness-to-diameter ratio, concrete strength, and test orientation angle on the shear resistance of SPC pile. The study claimed that the addition of shear reinforcements to SPC piles boosts their shear capability, whereas the addition of strands and angle of test orientation have little effect on the piles' shear resistance. The optimum applied pre-stressing was found in a range of 4–8 MPa. The optimum values of t/d ratios in terms of material savings to shear resistance of the SPC pile fall in a range of 0.20 – 0.30. Morris Sensitivity Analysis (MSA) reveals that effective prestress and pile concrete strength are the most influential parameters of the shear capacity of SPC piles. This study provides important details for the SPC pile's shear design, illustrating its applicability in deep foundations in seismic areas.

Study on crease recovery property of warp-knitted jacquard spacer shoe upper material

Shoe upper materials are often subjected to repeated creasing in use, which affects their shape retention and aesthetic. The crease recovery property of fabrics is an important property that affects its serviceability. Six variants of warp-knitted jacquard spacer fabrics with different jacquard layer structures were selected and the crease recovery angles on six orientation angles were tested for 30 cycles. The relationship between different orientation angles and crease recovery angles was studied and the comprehensive index for evaluating the crease recovery property of fabric was extracted by the grey relation analysis. The effect of the jacquard layer structure and the number of cycles on crease recovery property was analyzed with MATLAB. The results indicated that the crease recovery angles on different orientation angles were significantly different, and the comprehensive index could evaluate the crease recovery property more reasonably. The influence of the 3-needle underlap and the chain underlap on the crease recovery property was the most significant, and the influence of the 3-needle underlap was greater than that of the chain underlap. Base on solid structure, reducing the proportion of mesh structure or adding semi-transparent structure could improve the crease recovery property. The change rule of crease recovery angles with the number of cycles could be elucidated by the exponential function.

Facile fabrication of THz metasurfaces by a spatially shaped femtosecond laser printing system

Terahertz (THz) metasurfaces provide unprecedented abilities to realize versatile THz wavefronts manipulations. Nevertheless, these high degree of freedom, non-periodic, densely arranged subwavelength unit cells pose numerous extreme parameter requirements for the fabrication of metasurfaces, presenting significant challenges to their practical application. Herein, a spatial shaping femtosecond laser printing system, based on spatial light modulation (SLM), is proposed for the creation of THz metasurfaces. Through programming the SLM with a sequence of computer-generated holograms (CGH) corresponding to C-shaped Bessel beams with varying opening angles and orientation angles, the C-shaped slit resonant rings with different geometric parameters—fundamental units of the metasurface—were precisely printed onto a gold film. To validate this technique, a THz metalens based on a phased gradient design and a THz holographic plate employing simultaneous phase and amplitude modulation were meticulously fabricated, displaying outstanding performance. Owing to the simple processing flow, high reproducibility, and wide applicability of materials, this technique stands out as a versatile and efficient approach for fabricating THz metasurfaces, with the potential to promote the commercialization of terahertz metasurfaces.

Fracture behavior of a Ni-20 wt.%Cr binary alloy processed by Laser Powder Bed Fusion: Influence of the specimen building orientation and rotation angle between layers

This work provides a comparative study on the influence of the manufacturing process on the tensile and fracture properties of a Ni-20 wt.%Cr binary alloy produced by Laser Powder Bed Fusion (L-PBF). Two main processing parameters were investigated: the orientation of the samples with respect to the building direction (horizontal and vertical) and the rotation angle between layers (67° and 90°). Tensile and three-point bending tests were conducted to study the mechanical behavior. Monotonic tensile results suggest that the choice of the printing parameters affected the yield and ultimate tensile strength values, but was not influential to elongation. An increase in yield and ultimate tensile strengths of up to 15 % was noted for horizontal specimens compared to the vertical ones, and an increase of 10 % for an angle of 67° rather than 90°. Fracture toughness values remained in a range of 200 to 450 kJ/m2 regardless of the set of parameters considered. For a rotation angle of 67°, the fracture toughness was similar for both building orientations, but vertical specimens exhibited better resistance to crack propagation after initiation, with a tearing modulus increased by 50 % compared to horizontal ones. In contrast, building orientation was detrimental to specimens built with a rotation angle of 90°, as both fracture toughness and tearing modulus decreased drastically (up to 70 %) for a horizontal orientation rather than a vertical one. Microstructural observations highlighted mixed fracture modes for all L-PBF configurations, though crack propagation seemed mainly intergranular for horizontal specimens, and transgranular for vertical specimens. Fracture mechanisms were mostly governed by the grain orientation, size and morphology, while the crystallographic texture and the nano-oxides located in the dendrite arm spacing had a second-order influence. The pores and meltpool boundaries did not appear to play a significant role in crack propagation.

Stable and robust discriminative sensing of illicit drug molecules utilizing a specific geometry of nanotubes

The possibility of detecting and discriminating drug molecules is of utmost importance for several areas, including such important fields as security, public health and industry. The adequate detection of this type of substances then affects key sectors of society and is the subject of several studies and works that attempt to improve such detection and discrimination. Among the new devices used to detect drug molecules, the development, both experimental and theoretical, of nanosensors plays an increasingly important role and is expected to significantly increase the pace of progress in this field. In this work we have calculated the electronic and transport properties of a series of nanoscale devices based on carbon nanotubes and metallic heteronanotubes with hBN strips. These devices are specifically designed to sense drug molecules of a certain size and discriminate between three of them, namely cocaine, heroin, and morphine. We have found that the devices can effectively feel the presence of the drug molecules and distinguish between them through changes in the transmission, the conductance and the current. We have also found that such quantities depend on the angle of orientation, which shows that these systems have also the potential to determine the angle at which the molecule passes through it, i.e. to angularly discriminate between them. Furthermore, we have computed the Seebeck coefficient and found that such quantity can also be utilized to distinguish between the compounds. We have in addition found that the compounds behave as acceptors (they acquire charge) when the walls of the device are nanotubes and as donors (they lose charge) when the nanotube walls are heteronanotubes. Finally, we calculated the binding energies and found that the systems are exothermic. Such energies are not, however, big enough to promote the stick of the molecules to the walls of the devices, which shows the suitability of them for sensing the compounds.

Improvement of Latent Heat Thermal Energy Storage Rate for Domestic Solar Water Heater Systems Using Anisotropic Layers of Metal Foam

Latent Heat Transfer Thermal Energy Storage (LHTES) units are crucial in managing the variability of solar energy in solar thermal storage systems. This study explores the effectiveness of strategically placing layers of anisotropic and uniform metal foam (MF) within an LHTES to optimize the melting times of phase-change materials (PCMs) in three different setups. Using the enthalpy–porosity approach and finite element method simulations for fluid dynamics in MF, this research evaluates the impact of the metal foam’s anisotropy parameter (Kn) and orientation angle (ω) on thermal performance. The results indicate that the configuration placing the anisotropic MF layer to channel heat towards the lower right corner shortens the phase transition time by 2.72% compared to other setups. Conversely, the middle setup experiences extended melting periods, particularly when ω is at 90°—an increase in Kn from 0.1 to 0.2 cuts the melting time by 4.14%, although it remains the least efficient option. The findings highlight the critical influence of MF anisotropy and the pivotal role of ω = 45°. Angles greater than this significantly increase the liquefaction time, especially at higher Kn values, due to altered thermal conductivity directions. Furthermore, the tactical placement of the anisotropic MF layer significantly boosts thermal efficiency, as evidenced by a 13.12% reduction in the PCM liquefaction time, most notably in configurations with a lower angle orientation.

The effect of pore morphology on thermal insulation properties of thermal barrier coatings

The inhomogeneous-geometry microstructures caused by pores make thermal barrier coatings (TBCs) to have excellent thermal insulation properties, thus ensuring that the superalloy matrix is stable in its service at higher temperatures. Consequently, significant attention has been paid to understand the relationship between pore morphology and thermal conductivity. However, unclear the influence mechanisms of pore morphology-thermal insulation properties leads to a poor guide to the structural tailoring for better thermal insulation for TBC. In this study, a finite element method was used to simulate the thermal transport behavior of porous structures, and the influence mechanism of pore morphology on the thermal transport behavior of coatings was clarified. It indicated that thermal conductivity has a significant dependence on the pore aspect ratio, orientation angle, and porosity. The thermal insulation properties would be enhanced when large aspect ratio prolate spheroids are inserted with a pillar at the center. Further, the results shed light on the heat transport process across highly porous structures and provide a guide to design the coating with high thermal insulation properties.

Broadband vortex beam generation by a reflective meta-surface based on a metal double-slit resonant ring

Recently, the meta-surface (MS) has emerged as a promising alternative method for generating vortex waves. At the same time, MS also faces the problem of a narrow bandwidth; in order to obtain a broad bandwidth, the MS unit cell structure becomes more and more complex, which will bring many inconveniences to the preparation process of MS devices. Therefore, we want to design a simple MS unit cell with a multi-frequency selection. In this paper, based on the principle of geometric phase, we design a simple reflective MS unit cell based on a metal double-slit resonant ring. We elaborate on the resonance mechanism of the MS unit cell. Under the normal incidence of circularly polarized (CP) waves, the reflection coefficient of the same polarization was greater than 85%. By rotating the orientation angle of the resonator on the MS unit cell, the continuous 2π phase coverage was satisfied in the frequency range of 0.52–1.1 THz, and the relative bandwidth becomes 71.6%. Based on this, we construct a vortex generator by using a 15×15 MS unit array. The right-handed circularly polarized (RCP) waves and left-handed circularly polarized (LCP) wave are separately incident on MS with topological charges of l=+1,+2,+3 under multiple resonant frequencies. The generated RCP vortex wave has topological charges of l=−1,−2,−3 and the generated LCP vortex wave has topological charges of l=+1,+2,+3. The numerical simulation results demonstrate that our designed MS, capable of achieving multiple resonance outcomes, can effectively operate in a multi-broadband mode and produce a wide-band vortex beam. In addition, we also calculate the pattern purity. Through theoretical analysis and numerical simulation, we prove that our designed MS can generate a broadband vortex wave.

Large Orientation Angle Buried Substrate Enables Efficient Flexible Perovskite Solar Cells and Modules.

Flexible perovskite solar cells (f-PSCs) have emerged as potential candidates for specific mechanical applications owing to their high foldability, efficiency, and portability. However, the power conversion efficiency (PCE) of f-PSC remains limited by the inferior contact between perovskite and flexible buried substrate. Here, an asymmetric π-extended self-assembled monolayer (SAM) (4-(9H-dibenzo[a,c]carbazol-9-yl)butyl)phosphonic acid (A-4PADCB) is reported as a buried substrate for efficient inverted f-PSCs. Employing this design strategy, A-4PADCB exhibits a significant orientation angle away from the surface normal, homogenizing the distribution of contact potentials. This enhancement improves the SAM/perovskite interface quality, controlling the growth of favorable perovskite films with low defect density and slight tensile stress. Integration of A-4PADCB into small-area f-PSCs and large-area flexible perovskite solar modules with an aperture area of 20.84cm2 achieves impressive PCEs of up to 25.05% and 20.64% (certified 19.51%), respectively. Moreover, these optimized A-4PADCB-based f-PSCs possess enhanced light, thermal, and mechanical stability. This research paves a promising avenue toward the design of SAM-buried substrates with a large orientation angle, regulating perovskite growth, and promoting the commercialization of large-area flexible perovskite photovoltaics.

Process parameter optimisation and characterisation of fused deposition modelling-polylactic acid (FDM-PLA) parts

Fused deposition modelling stands as a prominent method within the realm of three-dimensional printing for crafting sturdy parts. This process builds solid components through the successive deposition of molten polymer layers extruded from a nozzle. This paper investigates the effect of process parameters such as infill angle and orientation angle on surface roughness and tensile strength. The full factorial design of experiment has been considered for experimentation. Studies show that the orientation angle should be kept as low as possible for a better surface finish, whereas the infill angle has a less significant effect on surface roughness (within the experimental domain). It has also been noted that to get a better tensile strength one has to print the sample with a low infill angle and with a low orientation angle.

Simulation for Composite Cylindrical Pressure Hull using Progressive Response Surface Method

Response surface method (RSM) as a fitting method had been applied to composite cylindrical buckling problem. There are little researches focusing on the accuracy of the RSM. For most cylinder buckling problems, only angles of the fiber orientation had been considered as the important variables. This paper proposes a progressive response surface method (RSM) to approximate the buckling critical pressure for composite cylindrical pressure hull taking ply angles and ply thicknesses into account. This method is adopted to replace the finite element method (FEM) to rise the calculation efficiency, and the fitting model result in this method can be proved to be effective and accurate compared with 6 different RSM models. The results can demonstrate its accuracy and feasibility under ply angles and thicknesses for composite cylindrical buckling problem.

Broadband high-efficiency meta-holography from all-dielectric quasi-continuous metasurfaces

The compactness and particular optical design make metasurface a competitive candidate for holographic display and storage. Recently, the selection and optimization for the used metasurface structures and types have become research spots. Now the most researched and demonstrated meta-holograms are often based on discrete structures, which can achieve high efficiency but comparatively narrow working bandwidths or a wide wavelength range but low power efficiency. Therefore, contemporary meta-holograms struggle for realizing simultaneous broadband and high efficiency. In this paper, all-dielectric quasi-continuous metasurfaces composed of nanostrips are introduced to expand the operating bandwidth for high efficiency meta-holography. Benefiting from the associated Pancharatnam–Berry phase, the nanostrips with spatially orientation angles continuous changes can realize arbitrary phase modulation. For the first time, the average power efficiency of a meta-hologram is experimentally measured to be 56.63% over a broad wavelength band ranging from 500 to 1000 nm. In addition, based on this kind of all-dielectric quasi-continuous nanostrips, we also design and experimentally achieve multicolor three-dimensional (3D) holographic images. Actually, such all-dielectric quasi-continuous methodology proposed here can be used to design other functional meta-devices, including optical metalens, nanoprinting, and information encryption.

Seafloor Rayleigh ellipticity, measured from unoriented data, and its significance for passive seismic imaging in the ocean

SUMMARY Observations of the seafloor Rayleigh ellipticity contribute to seismic imaging in the ocean. To extract such observables from the arbitrarily oriented ocean–bottom seismometer (OBS) data, we develop an orthogonal-regression-based approach to measure the waveform amplitude ratios of the unoriented horizontal and vertical components. The amplitude ratios are then used to calculate the Rayleigh ellipticity (and the sensor orientation angle). The robustness of our method is verified by applications to both the unoriented OBS data and the well oriented on-land seismic data. As we propose to calculate the Rayleigh ellipticity directly from the unoriented three-component data, the measurement process avoids the complexity arising from the surface wave non-great-circle effects and uncertainties of the OBS sensor orientation angles. Overall the Rayleigh ellipticity measurements from our method are systematically higher than those by conventional analysis and show less uncertainties. Our analyses suggest that the Rayleigh ellipticity curve (14–60 s), which could be retrieved from the raw broad-band OBS data, is effective to constrain the oceanic lithosphere structure, and the accurate measurement of Rayleigh ellipticity curve is important. The potential of seafloor Rayleigh ellipticity for seismic imaging in the ocean is evidenced by a case study of the Japan Basin, the Sea of Japan. Considering the insufficient station coverage in the ocean, the single-station measurement of seafloor Rayleigh ellipticity is of significance for OBS community.

Robust Fast Fracture Plane Orientation Angle Search Algorithm for Puck 3D Inter-Fibre Failure Criterion

In the present work, a novel fast fracture plane orientation angle (FPOA) search algorithm for the 3D Puck failure criterion is proposed. In the 3D Puck failure criterion, a linear search algorithm is employed to calculate the maximum inter-fibre failure (IFF) value by iterating and comparing the IFF value for each FPOA. This process itself requires a substantial amount of computational resources. The proposed fast FPOA search algorithm is implemented to substitute the linear search algorithm in order to reduce the computational time. A total of 1×105 randomised stress cases are used to analyse the accuracy of the algorithm. The result was then compared with the Puck Stepwise Seach Method (SSM) and other fast FPOA search algorithms. The results show that the proposed fast FPOA search algorithm has better accuracy compared to the other fast FPOA search algorithms and is almost 5 times faster compared to the SSM algorithm by Puck. In addition, a subroutine contains the Puck failure criterion and the proposed fast FPOA search algorithm is embedded into a Finite Element Analysis (FEA) software to simulate the open-hole test (OHT) experiment on the composite material.

Numerical investigation of the heat transfer and flow pattern on tandem triangle-grooved cylinders

Modifying surface characteristics and geometric structure to regulate heat transfer and flow fields is a classical issue. The study of wake dynamics and heat transfer efficiency in tandem grooved cylinders hold fundamental importance. This research proposes a configuration of tandem cylinders with triangle-grooved surfaces and numerical simulates the vorticity, fluid forces, Strouhal numbers, and convective heat transfer in tandem grooved cylinders. The parameters investigated include orientation angles θ = 0°, 30°, 45°, 60°, 90° and Reynolds numbers Re = 75, 100, 125, 150, 175, 200. This study focuses on how the triangle-grooved angle (θ) and Re affect wake dynamics and thermal performance. Numerical results are validated against available data in the literature for tandem smooth and tandem grooved cylinders. The results indicate that, compared to tandem smooth cylinders, the positive vorticity intensity of tandem grooved cylinders is 35.7 % higher, while the negative vorticity intensity is 23.5 % lower. Further observations show that at θ = 45°, the pressure variation on the upstream cylinder is most significant, approximately twice that at θ = 0° and θ = 90°. Notably, the variation values of the downstream cylinder (β = 0°) at θ = 0° and θ = 45° are triple and double that of the upstream cylinder in TF mode, respectively. Additionally, at θ = 0°, the root mean square lift coefficient of the downstream cylinder reaches the maximum value (Re = 75–100), approximately 1.34. When Re = 125, CL(rms),1 decreases by 15.7 % to 1.13. Particularly, when Re = 100–150, the time-averaged drag coefficient of the downstream cylinder shows a peak value of approximately 1.02. Interestingly, at Re = 200, a tadpole-shaped thermal distribution forms in the wake region of the upstream cylinder. Furthermore, the time-averaged Nusselt number ratio (θ = 0°) exhibits a trend opposite to other cases over a broader range (125 ≤ Re ≤ 200) and peaks at Re = 200, approximately 1.24.

Nonlinear thermal flutter of variable angle tow composite laminates in supersonic airflow

Compared with traditional composite materials, variable stiffness composite materials with curvilinear fiber paths have higher design flexibility and the potential to improve structural efficiency. In view of this, the nonlinear flutter characteristics of Variable Angle Tow (VAT) composite laminates with thermal effect in supersonic airflow are investigated in this paper. The proposed panel flutter model is developed based on the von Kármán large deformation plate theory. The thermal stress is approximated according to the quasi-steady thermal stress theory, whilst the aerodynamic pressure is calculated based on the first-order piston theory. The aerothermoelastic equations of motion are first established using Hamilton’s variational principle, and the Rayleigh-Ritz method is then applied to solve the governing equations in the space domain. The time-domain nonlinear equations are solved through the fourth-order Runge-Kutta method. The accuracy and convergence of the proposed method are verified through the comparisons with the results available in the literature. The effects of several parameters such as fiber orientation angle, thermal load, and aerodynamic pressure on the nonlinear flutter responses of VAT laminates are comprehensively discussed. Several dynamic behaviors of VAT laminates, including stable flat, buckled, Limit Cycle Oscillation (LCO), multi-periodic motion, quasi-periodic motion, and chaotic motion, are revealed by using the time history, phase portrait, Poincaré map, and bifurcation diagram. The results presented herein may be beneficial for the design of VAT laminates in supersonic airflow.

Evolution of elliptical SAXS patterns in aligned systems.

Small-angle X-ray and neutron scattering (SAXS and SANS) patterns from certain semicrystalline polymers and liquid crystals contain discrete reflections from ordered assemblies and central diffuse scattering (CDS) from uncorrelated structures. Systems with imperfectly ordered lamellar structures aligned by stretching or by a magnetic field produce four distinct SAXS patterns: two-point 'banana', four-point pattern, four-point 'eyebrow' and four-point 'butterfly'. The peak intensities of the reflections lie not on a layer line, or the arc of a circle, but on an elliptical trajectory. Modeling shows that randomly placed lamellar stacks modified by chain slip and stack rotation or interlamellar shear can create these forms. On deformation, the isotropic CDS becomes an equatorial streak with an oval, diamond or two-bladed propeller shape, which can be analyzed by separation into isotropic and oriented components. The streak has elliptical intensity contours, a natural consequence of the imperfect alignment of the elongated scattering objects. Both equatorial streaks and two- and four-point reflections can be fitted in elliptical coordinates with relatively few parameters. Equatorial streaks can be analyzed to obtain the size and orientation of voids, fibrils or surfaces. Analyses of the lamellar reflection yield lamellar spacing, stack orientation (interlamellar shear) angle α and chain slip angle ϕ, as well as the size distribution of the lamellar stacks. Currently available computational tools allow these microstructural parameters to be rapidly refined.