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2021 ◽  
Vol 2091 (1) ◽  
pp. 012014
Author(s):  
K V Pozhar ◽  
M O Mikhailov ◽  
E A Polyakova ◽  
E L Litinskaia

Abstract The paper considers the method of diffuse reflectance spectroscopy for noninvasive glucose level measuring in biological tissues. It is proposed a portable implementation of the system, based on a laser diode with a wavelength of 1600 nm and a power of 30 mW, operating in a pulsed mode, as well as a set of NIR-photodiodes located around the laser. The measuring system has been tested on model solutions with diffuse reflectance from polystyrene and pigskin. In the course of measurements on fixed system, an error of ~17 mg/dl is observed, which can be reduced by improving miniature laser sources.


2021 ◽  
Vol 9 (3) ◽  
pp. 33-38
Author(s):  
Raed Alahmdi ◽  
◽  
Abdulrahman Alansari ◽  
Mohanad Abualkhair ◽  
Abdulrahman Almoghamisi ◽  
...  

The main problem in studying the feasibility of solar systems is the enormous gap between theory and experimental radiation intensity, so to get accurate results there is a need for studying energy production in the site of the system empirically. In this study, the energy production of both fixed PV panel system and the system with single-axis tracking were empirically evaluated in Medina, Saudi Arabia. The two systems had the same 270 Wp PV panel. The fixed system was tilted by 23.5 degrees, and the single-axis tracker was tilted by 26 degrees. Both systems had an azimuth angle of zero degrees. A closedloop three-points controller was used to control the tracker with 120 degrees rotation range. The two systems operated simultaneously in July, and the data were collected for 14 days. The empirical results showed that the tracker increased the generated energy by 48.5% during the testing period. As a comparing method, a modified ASHRAE model was used to estimate the increase in the panel's energy output with and without the single-axis tracker, and RMSE and MBE were calculated. It's been found that the experimental energy generation is 10%, 5% less than the estimation of the modified model for the fixed system and the tracking system, respectively. Finally, based on the analysis, it's been estimated that the singleaxis tracker will increase the generated energy by 22.5% yearly in Medina.


2021 ◽  
pp. 1-61
Author(s):  
Ben Smyth

We propose a definition of ballot secrecy as an indistinguishability game in the computational model of cryptography. Our definition improves upon earlier definitions to ensure ballot secrecy is preserved in the presence of an adversary that controls ballot collection. We also propose a definition of ballot independence as an adaptation of an indistinguishability game for asymmetric encryption. We prove relations between our definitions. In particular, we prove ballot independence is sufficient for ballot secrecy in voting systems with zero-knowledge tallying proofs. Moreover, we prove that building systems from non-malleable asymmetric encryption schemes suffices for ballot secrecy, thereby eliminating the expense of ballot-secrecy proofs for a class of encryption-based voting systems. We demonstrate applicability of our results by analysing the Helios voting system and its mixnet variant. Our analysis reveals that Helios does not satisfy ballot secrecy in the presence of an adversary that controls ballot collection. The vulnerability cannot be detected by earlier definitions of ballot secrecy, because they do not consider such adversaries. We adopt non-malleable ballots as a fix and prove that the fixed system satisfies ballot secrecy.


2021 ◽  
Vol 73 (4) ◽  
pp. 893-901
Author(s):  
A.R.G. Macedo ◽  
S. Sühnel ◽  
C.A.M. Cordeiro ◽  
E.S.C.L. Nunes ◽  
N.C. Sousa ◽  
...  

ABSTRACT Survival and growth of the native oyster Crassostrea gasar along the juvenile and adult phases were evaluated in three different stocking densities [low (D), medium (2D) and high (3D)] and in two grow-out systems (fixed and floating system). The fixed system consisted of a rack made with PVC, fixed from the bottom with wood sticks. The floating system consisted of floating bags suspended by a rack made with PVC and maintained submerged from the seawater surface by eight floats. Survival and shell height of oysters cultured after 30, 60 and 90 days were registered in each phase and in each grow-out system. Results showed that the grow-out system did not affect survival and growth of C. gasar in the juvenile and adult phases. The tested densities affected the survival of oysters cultured over time in both phases but did not affect oyster growth. At times analyzed, it was observed positive growth in juvenile oysters grow after 90 days of culture. However, in the adult phase, no growth was observed after 90 days of culture. Oyster yield was higher in the density 3D, in both juvenile and adult phases. These findings contributed to the development of the oyster C. gasar culture.


2021 ◽  
Vol 67 (1) ◽  
pp. 17-22
Author(s):  
Bogdan Mihai Gălbinaşu ◽  
◽  
Veronica Bucur ◽  
Ion Pătraşcu ◽  
◽  
...  

The main objective of inserting dental implants in various clinical situations is to avoid mobile prosthetic restorations or to obtain a better stability. In this way, patients are offered increased comfort and better integration of prosthetic restorations into the stomatognathic complex. The purpose of this case presentation is to highlight a case of complex oral rehabilitation in which the Sky Fast and Fixed system (Bredent GmbH, Senden, Germany) was chosen, in the case of maxillary restoration, thus avoiding a mobile prosthetic restoration. The result demonstrates a superior aesthetic rehabilitation than the initial situation, obtaining a significant improvement from the first treatment session.


2021 ◽  
pp. 496-504
Author(s):  
Haihong Wang ◽  
Jingshi Tang ◽  
Jinjun Zheng ◽  
Qiuli Chen ◽  
Chengbin Kang ◽  
...  

Author(s):  
Chan Men Loon ◽  
Muhamad Zalani Daud

This paper presents development of a prototype sensorless dual axis solar tracker for maximum extraction of solar energy. To prove the concept and evaluate the proposed algorithm, a low cost widely availabe materials were used which was programmed based on Arduino microcontroller. The porposed algorithm works based on two search methods namely the global search that approximates the best point location in a region, and local search that further determines the actual sun’s position. Experimental results showed that the proposed algorithm gives better performance compared to the existing sun position algorithm (SPA) - based method as well as the fixed panel system. In terms of total output power, the proposed algorithm gives 17.96% more efficient than the fixed system and 6.38% better than the SPA-based system. Furthermore, the percentage error of the experimental measured angle to the actual sun azimuth angle was relatively minimal (less than 3%) during clear day operation. The system was proven to be effective in tracking the sun for improved energy production of solar PV panels and the proposed algorithm also can be used for designing the tracker with larger size of solar PV systems.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Dražen Glavan ◽  
Anja Marunović ◽  
Tomislav Prokopec ◽  
Zahra Zahraee

Abstract We consider the Abelian Higgs model in the broken phase as a spectator in cosmological spaces of general D space-time dimensions, and allow for the condensate to be time-dependent. We fix the unitary gauge using Dirac’s formalism for constrained systems, and then quantize the gauge-fixed system. Vector and scalar perturbations develop time­dependent masses. We work out their propagators assuming the cosmological background is that of power-law inflation, characterized by a constant principal slow-roll parameter, and that the scalar condensate is in the attractor regime, scaling as the Hubble rate. Our propagators correctly reduce to known results in the Minkowski and de Sitter space limits. We use the vector propagator to compute the equal-time correlators of electric and magnetic fields and find that at super-Rubble separations the former is enhanced, while the latter is suppressed compared to the vacuum fluctuations of the massless vector field. These correlators satisfy the hierarchy governed by Faraday’s law.


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