Azimuthal Orientation Research Articles

Dynamics and statistics of reorientations of large-scale circulation in turbulent rotating Rayleigh-Bénard convection

We present a direct numerical simulation to investigate the dynamics and statistics of reorientations of large-scale circulation (LSC) in turbulent rotating Rayleigh-Bénard convection for air (Pr = 0.7) contained in a cylindrical cell with unit aspect ratio. A wide range of rotation rates (0 ≤ Ro−1 ≤ 30) is considered for two different Rayleigh numbers Ra = 2 × 106 and 2 × 107. Using the Fourier mode analysis of time series data obtained from the different probes placed in the azimuthal direction of the container at the midplane, the orientation and associated dynamics of LSC are characterized. The amplitude of the first Fourier mode quantifies the strength of LSC, and its phase Φ1 gives the information on the azimuthal orientation of LSC. Based on the energy contained in the Fourier modes, different flow regimes are identified as the rotation rate is varied for a given Rayleigh number. The LSC structure is observed in the low rotation regime (Ro−1 ≲ 1), while the presence of other flow structures, namely, quadrupolar and sextupolar, is obtained at high rotation rates. In the LSC regime, a strong correlation between the orientation of LSC structure and the heat transfer and boundary layer dynamics is observed. At low rotation rates, the dissipation rates follow the log-normal behavior, while at higher rotation rates, a clear departure from log-normality is noted. Different types of reorientations, namely, rotation-led, cessation-led, partial, and complete reversal, are identified. The distribution of change in orientation of LSC follows a power law behavior as P(|ΔΦ1|) ∝|ΔΦ1|−m, with the exponent m ≈ 3.7. In addition, the statistics of time interval between successive reorientations follow a Poisson distribution. These observations are in good agreement with earlier experimental results.

Scattering Patterns of Orthogonally Polarized Light Components for Statistically Rotationally Invariant Mosaic Birefringent Layers

Using the method of two-point generalized Mueller matrices and the phase screen approximation, we have studied the relationship between the shape of the angular spectra of linearly polarized components of light scattered by randomly inhomogeneous layers of a birefringent material and the correlation structural characteristics of the layers. For statistically rotationally invariant layers, the structural conditions for three types of scattering patterns of linearly polarized components have been revealed: (i) patterns invariant with respect to the azimuthal rotation by 180°, (ii) patterns invariant with respect to the azimuthal rotation by 90°, and (iii) patterns possessing a circular symmetry. For mosaic birefringent layers consisting of homogeneous fragments with different azimuthal orientations of their optic axes, a relationship between the correlation structural properties of the layer and the shape of the scattering pattern of polarized components has been determined. In particular, conditions for the observation of crosslike four-lobed scattering patterns in crossed and parallel polarizers have been determined and the structural characteristic that is responsible for the orientation of such a scattering pattern with respect to the direction of polarization of the incident light has been found. The inferences that were derived have been supported by experimental data and results of numerical simulations.

Magnetization-induced chirality in second harmonic generation response of U-shaped permalloy nanostructures

Magnetization-induced circular dichroism (CD) in optical second harmonic generation (SHG) is observed in planar symmetrical arrays of U-shaped permalloy nanostructures. We demonstrate that extrinsic chirality of an array leads to the CD effect that strongly depends on the azimuthal orientation of the sample. In the absence of magnetization, the value of the SHG CD effect averaged over $2\ensuremath{\pi}$ azimuthal angle is zero, while up to 6% averaged SHG CD appears as the dc magnetic field is applied along the symmetry axis of the structure. Importantly the averaged SHG CD effect changes its sign under the reversal of the magnetic field, which corresponds to the appearance of magnetization driven true chirality in an array of symmetric magnetic nanostructures.

Influence of nanostructure formation on the crystal structure and morphology of epitaxially grown Gd2O3 on Si(001).

The influence of growth conditions on the layer orientation, domain structure and crystal structure of gadolinium oxide (Gd2O3) on silicon (001) has been investigated. Gd2O3 was grown at low (250°C) and high (850°C) temperatures with different oxygen partial pressure as well as a temperature ramp up during growth. At low temperature, the cubic bixbyite type of crystal structure with space group Ia{\bar 3} was grown at low oxygen partial pressure. The layers consist of two domains oriented orthogonal to each other. The epitaxial relationships for the two domains were found to be Gd2O3(110)[001]||Si(001)[110] and Gd2O3(110)[001]||Si(001)[{\bar 1}10], respectively. Applying additional oxygen during growth results in a change in crystal and domain structures of the grown layer into the monoclinic Sm2O3-type of structure with space group C2/m with (20\bar 1) orientation and mainly two orthogonal domains with the epitaxial relationship Gd2O3(20\bar 1)[010]||Si(100)〈110〉 and a smooth surface morphology. Some smaller areas have two intermediate azimuthal orientations between these variants, which results in a six-domain structure. The change in crystal structure can be understood based on the Gibbs-Thomson effect caused by the initial nucleation of nanometre-sized islands and its variation in diameter with a change in growth conditions. The crystal structure remains stable even against a temperature ramp up during growth. The layers grown at high temperature exhibit a nanowire-like surface morphology, where the nanowires have a cubic crystal structure and are aligned orthogonal to each other along the 〈110〉 in-plane directions. An increase in oxygen supply results in a reduced length and increased number of nanowires due to lower adatom mobility. The results clearly indicate that both kinetic and thermodynamic factors have a strong impact on the crystal structure, epitaxial relationship and morphology of the grown layers.

SIMULATED FINE STRUCTURES OF SPIRAL RAINBANDS IN TYPHOON CHANCHU (2006)

In this study, fine structures of spiral rainbands in super Typhoon Chanchu (2006) are examined using an Advanced Research Weather Research and Forecast (WRF-ARW) model simulation with the finest grid size of 2 km. Results show that the simulation reproduces well Typhoon Chanchu’s track, intensity and basic structures. According to their locations and features, spiral rainbands are classified into principal, secondary, inner and distant rainbands, and their dynamic and thermodynamic features are investigated. The principal rainbands remain quasi-stationary with respect to Chanchu’s center and exhibit a wavenumber-1 feature with their outer edges separated by dry air. The secondary rainbands that occur on the radially inward side of the principal rainbands move around Chanchu's center. The inner rainbands are closest to the center. They propagate both radially outward and azimuthally with time. The distant rainbands are located outside the inner-core region, and have stronger and continuous updrafts compared to the other rainbands. Distant rainbands are inward-sloping with height along the radial direction and have a cold pool in the low layers, whereas the principal and secondary rainbands lean radially outward with height. The inner rainbands do not show tilting with height along the radial direction. However, there are few vertical tilting cells along the azimuthal orientation among the four types of rainbands. The simulated radar reflectivity cores in all rainbands are collocated with the maxima of updrafts and equivalent potential temperatures in the low layer, indicating the important roles of energy supply in the boundary layer in determining the development of the rainband convection.

Scattering Modeling of Urban Oriented Buildings in PolSAR images by Using Adaptive Statistical Distribution

The cross-polarized scattering (HV) of polarimetric synthetic aperture radar (PolSAR) data is caused not only by forest but also by urban buildings with azimuth orientation angles. Since the general double scattering in model-based decomposition does not support their dominant scattering mechanism, it’s still a challenge for modeling the scattering mechanism of oriented buildings. In this paper, the HV induced by oriented buildings is modeled by a rotated dihedral corner reflector. The cross scattering matrix of oriented building is obtained by averaging a cosine squared distribution with its peak at the dominant polarimetric orientation angle (DPOA) of an area and an adaptive width. The relation between DPOA and distribution width is acquired. Then an optimization strategy which eliminates the negative power and balances time and efficiency is proposed to estimate the scattering contributions. The proposed algorithm is tested on AIRSAR data of San Francisco and UAVSAR of San Diego and the results confirm the effectiveness.

Картины рассеяния ортогонально поляризованных компонент света для статистически вращательно-инвариантных мозаичных двулучепреломляющих слоев

AbstractUsing the method of two-point generalized Mueller matrices and the phase screen approximation, we have studied the relationship between the shape of the angular spectra of linearly polarized components of light scattered by randomly inhomogeneous layers of a birefringent material and the correlation structural characteristics of the layers. For statistically rotationally invariant layers, the structural conditions for three types of scattering patterns of linearly polarized components have been revealed: (i) patterns invariant with respect to the azimuthal rotation by 180°, (ii) patterns invariant with respect to the azimuthal rotation by 90°, and (iii) patterns possessing a circular symmetry. For mosaic birefringent layers consisting of homogeneous fragments with different azimuthal orientations of their optic axes, a relationship between the correlation structural properties of the layer and the shape of the scattering pattern of polarized components has been determined. In particular, conditions for the observation of crosslike four-lobed scattering patterns in crossed and parallel polarizers have been determined and the structural characteristic that is responsible for the orientation of such a scattering pattern with respect to the direction of polarization of the incident light has been found. The inferences that were derived have been supported by experimental data and results of numerical simulations.

Topological properties of bound states in the continuum in geometries with broken anisotropy symmetry

Waveguiding structures made of anisotropic media support bound states in the continuum (BICs) that arise when the radiation channel of otherwise semi-leaky modes is suppressed. Hitherto, only structures with optical axes aligned in symmetric orientations inside the waveguide plane, where BICs appear as lines in the momentum-frequency dispersion diagram, have been considered. Here we address settings where such symmetry is broken and unveil a number of fundamental new features. Weak and strong symmetry-breaking regimes are identified, corresponding to azimuthal and polar optical axes orientation asymmetries, respectively. The azimuthal symmetry-breaking is found to still preserve the existence loci of BICs in the momentum-frequency dispersion diagram as lines. However, all possible BICs become interferometric, while the polarization separable states that occur in symmetric settings cease to exist. The polar symmetry-breaking has stronger effects and transforms the BICs' existence loci from lines to points, which correspond to full-vector states that exist at discrete values of the optical axis orientation for a given wavelength. Such transformation results in fundamental changes in the topological properties of the radiated field around the BICs.

Paracetamol micro-structure analysis by optical mapping

Domain structure of paracetamol - popular antipyretic analgesic - was investigated by infrared (IR) spectroscopy using synchrotron radiation. Absorbance and retardance maps reveal molecular orientation inside the micro-domains of the paracetamol form II which has a better water solubility and compressibility compared to the commercially used forms I. The developed method of analysis representing orientation of optical slow(fast)-axis is compared with azimuthal orientation of the absorbance at several specific IR bands using vector maps. High brightness of synchrotron radiation and hyper-spectral mapping of structural domains in paracetamol clearly reveals the domain boundaries and can potentially be used to observe in situ intra-phase transformations of paracetamol forms-I, II, III and melting, which are important for making medical tablets and powders by an industrial process.

Desempenho de um sistema solar fotovoltaico com diferentes inclinações e orientações azimutais em cidades da Paraíba

<p>The Sun is the main source of energy for the Earth. The conversion of solar to electric energy can be done through photovoltaic systems, whose performance depends on variables such as slope angle and azimuth orientation. The objective of this project was to evaluate the annual production of electric energy according to the function of the angles of inclination and azimuth orientation for a residential photovoltaic system connected to the grid in six municipalities of Paraíba. The analysis was performed via a System Advisor Model simulation for a system with a capacity of 1500 Wp. The reference system considered in this study was oriented to the geographic north and the slope was equal to the local latitude. The variation of the angle of inclination of the module was considered at intervals between 0 ° and 90 ° and the azimuthal angle ranged from 0 ° to 360 °. The annual production of energy in each system positioning was normalized by the yield of the reference system to obtain the losses for each orientation. Results indicated that concerning the energy produced by the system in the horizontal condition and regardless of the azimuthal angle, the losses did not exceed 1% in relation to the reference system. It was also observed that there is a wide range of slopes and orientations so that a photovoltaic arrangement can be applied with the minimum loss of electricity generation in relation to the reference system.</p>

Analysis of aeromagnetic anomalies and structural lineaments for mineral and hydrocarbon exploration in Ikom and its environs southeastern Nigeria

The purpose of this study is to analyze the aeromagnetic data of Ikom and its environs in Cross-River State, Nigeria in order to delineate the structural lineaments according to their spatial and directional attributes as well as define the depth to magnetic causative bodies. This was achieved with the aid of an acquired, digitized and processed aeromagnetic intensity contour map covering Ikom and its adjacent areas. The aeromagnetic data was subjected to diverse data enhancement and transformation routines. Regional-residual analysis was implemented on the total magnetic intensity map (contour interval = 20 nT) to generate a residual magnetic intensity contour map. Results show that the area is characterized by a very complex pattern of magnetic intensities of both long and short wave-lengths. Sequel to the regional-residual anomaly separation, azimuth orientation of the lineament structures delimited on the maps portray NS and NE-SW as the principal trends with E-W and NW-SE as the minor trends. Two depth sources were obtained by employing the commonly known Peter's half-slope method. Depth range for the deeper causative sources is 0.83 km–3.5 km with a magnetic intensity range of −30 nT to −220 nT while the superficial sources had a range of 0.2 km–0.75 km and a magnetic intensity that vary from −10 nT to 20 nT. The deeper magnetic sources are attributed to the underlying pre-Cambrian basement complex rocks and intra basement structures such as fractures and faults whereas the superficial sources are due to basement intrusives as well as ore-bearing veins present in the overlying Cretaceous rocks. The shallow basement depth and prevalence of intrusives and linear structures are indications of an area of good mineral prospects but unfavorable for hydrocarbon formation.

Efficient Spectroscopy of Exoplanets at Small Angular Separations with Vortex Fiber Nulling

Abstract Instrumentation designed to characterize potentially habitable planets may combine adaptive optics and high-resolution spectroscopy techniques to achieve the highest possible sensitivity to spectral signs of life. Detecting the weak signal from a planet containing biomarkers will require exquisite control of the optical wavefront to maximize the planet signal and significantly reduce unwanted starlight. We present an optical technique, known as vortex fiber nulling (VFN), that allows polychromatic light from faint planets at extremely small separations from their host stars (≲λ/D) to be efficiently routed to a diffraction-limited spectrograph via a single-mode optical fiber, while light from the star is prevented from entering the spectrograph. VFN takes advantage of the spatial selectivity of a single-mode fiber to isolate the light from close-in companions in a small field of view around the star. We provide theoretical performance predictions of a conceptual design and show that VFN may be utilized to characterize planets detected by radial velocity (RV) instruments in the infrared without knowledge of the azimuthal orientation of their orbits. Using a spectral template-matching technique, we calculate an integration time of ∼400, ∼100, and ∼30 hr for Ross 128 b with Keck, the Thirty Meter Telescope, and the Large Ultraviolet/Optical/Infrared Surveyor, respectively.

Effect of Tilted Magnetic Anisotropy on the Deterministic Current-Induced Magnetization Reversal in Quasi-Perpendicularly Magnetized Ta/Pt/CoFeB/Pt Multilayers

Deterministic current-induced magnetization reversal is observed in quasi-perpendicularly magnetized Ta/Pt/CoFeB/Pt multilayer thin films without the assistance of an in-plane field. In a quasi-perpendicularly magnetized system, the anisotropy is tilted slightly away from the normal to the film plane. This tilt in the anisotropy is obtained by growing the films in an oblique-angle sputter deposition technique, which results in a gradient in the thickness of the layers. To estimate the tilt, out-of-plane hysteresis loop measurements are performed in the presence of an in-plane bias field. The effect of the tilt is reflected in the shift in the hysteresis loop. A measurement of this shift at different relative azimuthal orientations of the in-plane projection of the tilt direction with respect to the in-plane bias field direction gives a tilt of 0.74° (±0.06°) in Ta(3 nm)Pt(3 nm)CoFeB(0.5 nm)Pt(1 nm) with all the layers having a thickness gradient. In addition, field-induced domain wall velocity measurements in the creep regime on Ta(3 nm)Pt(3 nm)CoFeB(0.5 nm)Pt(1 nm) thin film with a thickness gradient only in CoFeB layer give an elliptical profile for the domain wall. In the current-induced magnetization reversal studies, threshold current density of $1.06 \times 10^{11}$ Am−2 is required to deterministically switch the device fabricated from Ta(3 nm)Pt(3 nm)CoFeB(0.5 nm)Pt(1 nm) thin film with all the layers having a thickness gradient. On application of in-plane bias, there is a shift in the threshold current densities given by $2.6 \times 10^{8}$ Am−2 of in-plane bias field.

Estimation of fracture weaknesses and integrated attenuation factors from azimuthal variations in seismic amplitudes

Seismic wave propagation in fractured reservoirs exhibits anisotropy and attenuation, which are in turn related to fracture properties (e.g., fracture density) and fluid parameters (e.g., moduli and viscosity). Based on the linear slip theory, stiffness parameters can be determined for fractured and dissipative rocks, from which integrated attenuation factors involving host-rock intrinsic attenuation and fracture-induced attenuation emerge. Using a simplified mathematical form for these stiffness parameters, a linearized mathematical relationship directly relating the reflection coefficient to fracture weaknesses and integrated attenuation factors is available. A two-step inversion approach, involving (1) an iterative damped least-squares algorithm to predict P- and S-wave moduli using seismic angle gathers along the fracture orientation azimuth and (2) an iterative inversion method to estimate fracture weaknesses and integrated attenuation factors from azimuthal amplitude differences, is examined. The objective function for the second step is constructed based on a Bayesian framework. Synthetic testing confirms that fracture weaknesses and integrated attenuation factors are stably determined from seismic amplitudes exhibiting a moderate signal-to-noise ratio. The approach is applied to a field data set from a fractured carbonate reservoir. We observe that geologically reasonable results of fracture weaknesses and integrated attenuation factors are obtained. We conclude that this estimation procedure provides a reliable tool in fracture prediction and inverted attenuation factors appear as additional proofs to identify fluid type in fractured reservoirs.

Colorado Plateau Coring Project, Phase I (CPCP-I): a continuously cored, globally exportable chronology of Triassic continental environmental change from western North America

Abstract. Phase 1 of the Colorado Plateau Coring Project (CPCP-I) recovered a total of over 850 m of stratigraphically overlapping core from three coreholes at two sites in the Early to Middle and Late Triassic age largely fluvial Moenkopi and Chinle formations in Petrified Forest National Park (PFNP), northeastern Arizona, USA. Coring took place during November and December of 2013 and the project is now in its post-drilling science phase. The CPCP cores have abundant detrital zircon-producing layers (with survey LA-ICP-MS dates selectively resampled for CA-ID-TIMS U-Pb ages ranging in age from at least 210 to 241 Ma), which together with their magnetic polarity stratigraphy demonstrate that a globally exportable timescale can be produced from these continental sequences and in the process show that a prominent gap in the calibrated Phanerozoic record can be filled. The portion of core CPCP-PFNP13-1A for which the polarity stratigraphy has been completed thus far spans ∼215 to 209 Ma of the Late Triassic age, and strongly validates the longer Newark-Hartford Astrochronostratigraphic-calibrated magnetic Polarity Time-Scale (APTS) based on cores recovered in the 1990s during the Newark Basin Coring Project (NBCP). Core recovery was ∼100 % in all holes (Table 1). The coreholes were inclined ∼60–75∘ approximately to the south to ensure azimuthal orientation in the nearly flat-lying bedding, critical to the interpretation of paleomagentic polarity stratigraphy. The two longest of the cores (CPCP-PFNP13-1A and 2B) were CT-scanned in their entirety at the University of Texas High Resolution X-ray CT Facility in Austin, TX, and subsequently along with 2A, all cores were split and processed at the CSDCO/LacCore Facility, in Minneapolis, MN, where they were scanned for physical property logs and imaging. While remaining the property of the Federal Government, the archive half of each core is curated at the NSF-sponsored LacCore Core Repository and the working half is stored at the Rutgers University Core Repository in Piscataway, NJ, where the initial sampling party was held in 2015 with several additional sampling events following. Additional planned study will recover the rest of the polarity stratigraphy of the cores as additional zircon ages, sedimentary structure and paleosol facies analysis, stable isotope geochemistry, and calibrated XRF core scanning are accomplished. Together with strategic outcrop studies in Petrified Forest National Park and environs, these cores will allow the vast amount of surface paleontological and paleoenvironmental information recorded in the continental Triassic of western North America to be confidently placed in a secure context along with important events such as the giant Manicouagan impact at ∼215.5 Ma (Ramezani et al., 2005) and long wavelength astronomical cycles pacing global environmental change and trends in atmospheric gas composition during the dawn of the dinosaurs.

Fracturing of Migmatite Monitored by Acoustic Emission and Ultrasonic Sounding

Here, we present an experimental study of the fracturing of anisotropic migmatite with plane-parallel structure (foliation). Four specimens, with different dips of foliation, including subhorizontal (13°), subvertical (86°), and oblique (47°, 67°), were uniaxially loaded up to failure. Acoustic emission monitoring and ultrasonic sounding were applied for fracturing characterization. In case of subhorizontal and subvertical foliation, the tensile source type played an important role before reaching nucleation stress when shearing became dominant. The dominance of non-tension microcracking was characteristic for oblique foliation. The uniaxial loading of migmatite resulted in triaxial stress state regardless of the foliation dip. The minimum stress axis was in the subhorizontal direction of the foliation dip. The triaxial stress state caused the preferential orientation of induced shear and tension microcracks that had the same azimuthal orientation as the foliation. Preferential microcracking resulted in preferential orientation of the failure plane. Based on the anisotropic behavior of migmatite’s characteristic mechanical properties, as well as its mechanism of failure that is typical for anisotropic rocks, the obtained conclusions may be generalized for other types of metamorphic anisotropic rocks with a plane-parallel structure.

Phosphorylation status of peptide monolayers modulates hydrogen bonding and orientations of nematic liquid crystals

ABSTRACTWe report on the azimuthal orientations of nematic liquid crystals (LCs) on monolayers of dipeptides and tripeptides containing cysteine (C) and either tyrosine (Y), serine (S) or threonine (T). Measurements performed with 5CB and TL205 (with and without doping with trimethylamine), and dipeptide monolayers in which we removed the –OH groups of CY, CS or CT, led us to conclude that hydrogen bonding strongly influences LC orientations on CY but not CS or CT monolayers. Chemical force microscopy and cyclic voltammetry support the hypothesis that intra-monolayer hydrogen bonding within monolayers of CS and CT occurs preferentially to hydrogen bonding with 5CB. In contrast, the orientations of the LCs on tripeptide monolayers of CAY, CAS or CAT, where A is alanine, were all influenced by hydrogen bonding, consistent with a decrease in surface density of tripeptides (as compared to dipeptides; supported by x-ray photoelectron spectroscopy) and increase in hydrogen bonding with the LC overlayer. Phosphorylation of monolayers that oriented 5CB through hydrogen bonding led to easily measured changes in LC orientation. Overall, our results advance the rational design of LC materials with internal order that is coupled to biologically relevant chemical modifications of oligopeptides and proteins.

Effect of cross wire tab orientation on twin jet mixing characteristics

The effect of the relative azimuthal orientation of the cross wires, placed at the exit of two identical converging-diverging nozzles, on the flow field of the twin jet is studied experimentally. The nozzle is designed for Mach number of 1.8, with the inter-nozzle spacing of 1.5 and 2.25 times the nozzle exit diameter. Pitot pressure surveys are conducted along the centerline and the cross-stream direction of the twin jet. Cross wire is shown to be successful in reducing the core length and enhancing the mixing characteristics at all the NPRs studied. The combinations of the horizontal and vertical orientation of the cross wire are found to significantly influence the development of the jet flow field for twin jets. Wires, both mounted vertically, are found to be superior in enhancing the mixing characteristics and reducing the core length. The shadowgraph images reveal that the wire bifurcates the jet and displaces the fluid away from the centerline. Strong shocks are formed near the cross wire, but the pressure losses and enhanced mixing of the jet fluid result in smaller supersonic core length with less number of shock-cells.

A METHOD FOR DETERMINING OF OPTIMAL TILT ANGLE AND ORIENTATION OF PV MODULES BASED ON MEASURED SOLAR RADIANCE DATA

For calculating and designing of photovoltaic (PV) plant, it is necessary to choose the optimal tilt angle and azimuth orientation of solar panels which will largely determine the electricity output produced by future PV plant during an operational calendar period. However, in order to determine these angles experimentally by monitoring the PV plant electricity yield at different panel’s positions, it will take many years. Therefore, it is advisable to develop a theoretical model, which a priori calculates the optimal tilt and azimuth angles of panels amounted in fixed positions. This paper assumes the maximum of the total radiation arrival per unit area on the receiving surface over the calendar period of PV plant operation as an optimization criterion for these angles. The calculation scheme has been applied for the whole year, for four year seasons and for a whole year period except winter. In the developed optimization method, the initial data are the geographical coordinates of the PV plant, the hourly sums of direct and diffuse radiation on the horizontal plane, as well as the reflectivity of the earth's surface. These data obtained by averaging the long-term measurements of the main solar radiation components are experimental ones. The developed computational scheme is based on nonlinear equations for the optimal tilt angles of panels first obtained for anisotropic solar radiation models. This scheme allows us to calculate the optimal panel angles for any operational PV plant period and for any region for which experimental radiation data are available. As the examples, we have calculated the graphs of the average daily radiation arrival dependencies on the panel’s position angles and have determined the optimal fixed tilt and azimuth angles for six cities of Russia located in different climatic zones. The method allows us to evaluate the gain in the electricity yield of PV plant when choosing the optimum tilt angles and azimuth of the panels, and to a djust the tilt angles to the optimum values for each season if this is envisaged by the PV string design.

Optimization of PV powered SPD switchable glazing to minimise probability of loss of power supply

Abstract Suspended particle device (SPD) glazing is an electrically actuated switchable glazing. It requires alternate current (AC) power supply to switch from opaque to transparent state. To power this glazing using PV device requires inverter. Optimization of AC powered switchable SPD glazing using photovoltaic (PV) device has been evaluated using loss of power supply probability (LPSP). Electrically switchable direct current (DC) powered electrochromic glazing was also considered in this investigation as it doesn't need any inverter to couple with PV. It is concluded that behaviour of these glazings is the dominant factor in performance optimization outweighting than azimuthal orientation and inclination of PV.