Iterative technique for generating numerical on-axis holograms of an object on tilted planes using Rayleigh-Sommerfeld approximation

We present a new iterative technique based on successive field propagation using the Reyleigh-Sommerfeld (RS) approximation, to generate by computer the amplitude on-axis hologram of an object on a tilted plane. The technique was validated doing optical and computational reconstruction of the hologram.

Optimization of Solar Panel Tilt and Azimuth Angle for Maximum Solar Irradiation and Minimum Loss for Rural Electrification

The earth receives solar power at a rate of 120 petawatts, meaning that the energy obtained from the sun in a single day could satisfy the world’s energy needs for almost twenty years. Africa is often considered and referred as the "Sun continent" or the continent where the Sun's influence is the greatest, yet over 600 million people in sub-Saharan Africa live without electricity. This inexhaustible, untapped, abundant, and environmentally friendly solar energy potential encouraged solar power generation technologies to flourish faster than any other renewable energy technology most especially in Africa. The amount of electricity generated by a fixed-tilt solar PV system depends on the orientation of the PV panel (tilt and azimuth angle) relative to the sun. The panel of a solar PV system collect solar radiation more efficiently when the sun's rays are perpendicular to the panel: when the sun hits it directly at a 90o degree angle; but the sun is a moving target. Not only does it move across the sky throughout the day, but it is higher in the sky in the dry season (winter) from October to March and lower in the sky in the wet season (summer) from April to September. Since the climate is usually characterized into two seasons, the system optimization presented in this paper was carried out based on: yearly irradiation yield (fixed tilted plane) to guarantee optimum solar irradiation throughout the year, with 0.0% loss with respect to optimum. The system eliminates the challenges associated with changing the solar panel orientation every season, or using the expensive and inefficient sun tracker in tracking sun energy; while guaranteeing higher energy production, better system performance, lower system losses, and low operational cost. The system optimization was carried out with the “PVsyst simulation software” made for PV system designers and researchers to predict the performance of different solar system configurations, evaluate the results, and identify the best approach for maximum energy production. This paper investigated the optimal tilt and azimuth angle for solar panel orientation techniques for a typical rural community in Nigeria (Ndikelionwu) to advance rural electrification. After series of simulation and optimization processes; the best yearly irradiation yield was recorded when the solar panel is at 40o tilt and 0o Azimuth angle; with 0.0% loss with respect to optimum. Keywords: Optimization, PVsyst, Solar Irradiation, Tilt and Azimuth Angle, Global on Collector Plane, Fixed Tilted Plane, Rural Electrification, Solar Panel Orientation And Yearly Irradiation Yield.

Flaw Detection on a Tilted Particleboard by Use of the Spec-Radiation Method

Herein, we present a novel approach to the spec-radiation method (a method of acoustical holography) for determining the sound distribution on a tilted particleboard by calculating a single plane and rotation in the frequency domain. The tilted particleboard allows testing without standing waves between the transmitter and the particleboard. This eliminates the need to evaluate several parallel planes and to search for values belonging to the tilted particleboard. The numerical requirements can be optimally exploited through a combination with a flaw detectability enhancement method. The results are supported by experiments on a wooden particleboard with flaw imitations. Finally, we showed, through a comparison with the usual procedure of identifying a flaw (calculating many parallel planes and then selecting the data belonging to the tilted plane), that the calculation of the tilted plane is up to 98.5% faster and improves the detectability of flaws in a tilted particleboard.

Large Angle Forward Diffraction by Chiral Liquid Crystal Gratings with Inclined Helical Axis

A layer of chiral liquid crystal (CLC) with a photonic bandgap in the visible range has excellent reflective properties. Recently, two director configurations have been proposed in the literature for CLC between two substrates with periodic photo-alignment: one with the director parallel to the substrates and one with the director in the bulk parallel to the tilted plane. The transmission experiments under large angles of incidence (AOI) presented in this work prove that, in the bulk, the director does not remain parallel with the substrates. Because of the inclined helical axis, the full reflection band can be observed at a smaller AOI than in planar CLC. For sufficiently large AOI, the reflection of diffracted light is prohibited by total internal reflection and efficient diffraction occurs in the forward direction.

Influence of device to device interconnection elements on the system behavior and stability

<p>This work has presented the<strong> </strong>interaction between tangential/sagittal cylindrical thin lens in the titled plane parallel crystal. Stability criterion parameters are measured under the control of curvature radius of a spherical mirror, the thickness of the tilted plane crystal, the refractive index of tilted plane crystal, the thickness for a plate of matter and phase angle of the sagittal cylindrical thin lens. Beam radius waist is plotted against the focal length of the tangential cylindrical thin lens. Focal length for both thin lens in resonator crystal is optimized to upgrade the resonator system operation efficiency.</p>

Robot assisted versus laparoscopic suturing learning curve in a simulated setting

Background Compared to conventional laparoscopy, robot assisted surgery is expected to have most potential in difficult areas and demanding technical skills like minimally invasive suturing. This study was performed to identify the differences in the learning curves of laparoscopic versus robot assisted suturing. Method Novice participants performed three suturing tasks on the EoSim laparoscopic augmented reality simulator or the RobotiX robot assisted virtual reality simulator. Each participant performed an intracorporeal suturing task, a tilted plane needle transfer task and an anastomosis needle transfer task. To complete the learning curve, all tasks were repeated up to twenty repetitions or until a time plateau was reached. Clinically relevant and comparable parameters regarding time, movements and safety were recorded. Intracorporeal suturing time and cumulative sum analysis was used to compare the learning curves and phases. Results Seventeen participants completed the learning curve laparoscopically and 30 robot assisted. Median first knot suturing time was 611 s (s) for laparoscopic versus 251 s for robot assisted (p < 0.001), and this was 324 s versus 165 (sixth knot, p < 0.001) and 257 s and 149 s (eleventh knot, p < 0.001) respectively on base of the found learning phases. The percentage of ‘adequate surgical knots’ was higher in the laparoscopic than in the robot assisted group. First knot: 71% versus 60%, sixth knot: 100% versus 83%, and eleventh knot: 100% versus 73%. When assessing the ‘instrument out of view’ parameter, the robot assisted group scored a median of 0% after repetition four. In the laparoscopic group, the instrument out of view increased from 3.1 to 3.9% (left) and from 3.0 to 4.1% (right) between the first and eleventh knot (p > 0.05). Conclusion The learning curve of minimally invasive suturing shows a shorter task time curve using robotic assistance compared to the laparoscopic curve. However, laparoscopic outcomes show good end results with rapid outcome improvement.

Optical Image Encryption System Using Several Tilted Planes

A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical system, in order to obtain the encrypted image. In this work, we propose to use tilted planes for the Fourier and the output planes of the optical DRPE encryption system with the purpose of adding two new security keys, which are the angles of the tilted planes. The optical diffraction on a tilted plane is computed using the angular spectrum of plane waves and the coordinate rotation in the Fourier domain. The tilted distributions at the intermediate and output planes of the optical DRPE encryption system are the second RPM and the encrypted image, respectively. The angles of the tilted planes allow improvement to the security of the encrypted image. We perform several numerical simulations with the purpose of demonstrating the validity and feasibility of the proposed image encryption system.