scholarly journals Optimization of Supercapacitor Assisted Surge Absorber (SCASA) Technique: A New Approach to Improve Surge Endurance Using Air-Gapped Ferrite Cores

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4337
Author(s):  
Sadeeshvara Udayanga Silva Thotabaddadurage ◽  
Nihal Kularatna ◽  
D. Alistair Steyn-Ross
Keyword(s):  
Magnetic Material ◽  
Experimental Work ◽  
The Novel ◽  
Transient Operation ◽  
Destructive Testing ◽  
Transient Conditions ◽  
New Approach ◽  
Test Standards ◽  
Present Design ◽  
Transformer Core

SCASA is a patented technique commercialized as a surge protector device (SPD) that adheres to UL-1449 test standards. Apart from the novel use of supercapacitors, SCASA design incorporates a coupled-inductor wound to a specially selected magnetic material of powdered-iron. In this study, we investigate the limitations of the present design under transient operation and elucidate ways to eliminate them with the use of air-gapped ferrite cores. In modelling the operation under 50 Hz AC and transient conditions, a permeance-based approach is used; in addition, non-ideal characteristics of the transformer core are emphasized and discussed with empirical validations. The experimental work was facilitated using a lightning surge simulator coupled with the 230 V AC utility mains; combinational surge-waveforms (6 kV/3 kA) defined by IEEE C62.41 standards were continuously injected into SPD prototypes during destructive testing. Such procedures substantiate the overall surge-endurance capabilities of the different core types under testing. With regard to optimizations, we validated a 95% depletion of a negative-surge effect that would otherwise pass to the load-end, and another 13–16% reduction of the clamping voltage verified the effectiveness of the methods undertaken. In conclusion, SCASA prototypes that utilized air-gapped cores revealed a greater surge endurance with improved load-end characteristics.

scholarly journals New Approach in the Application of Conjugated Polymers: The Light-Activated Source of Versatile Singlet Oxygen Molecule

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1098
Author(s):  
Agata Blacha-Grzechnik
Keyword(s):  
Conjugated Polymers ◽  
Singlet Oxygen ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Short Review ◽  
The Novel ◽  
New Approach ◽  
Intermolecular Energy ◽  
Intermolecular Energy Transfer ◽  
High Absorption

For many years, the research on conjugated polymers (CPs) has been mainly focused on their application in organic electronics. Recent works, however, show that due to the unique optical and photophysical properties of CPs, such as high absorption in UV–Vis or even near-infrared (NIR) region and efficient intra-/intermolecular energy transfer, which can be relatively easily optimized, CPs can be considered as an effective light-activated source of versatile and highly reactive singlet oxygen for medical or catalytic use. The aim of this short review is to present the novel possibilities that lie dormant in those exceptional polymers with the extended system of π-conjugated bonds.

Mobility-as-a-Service: Simulation of Multi-Modal Operations in Low-Density Cities

2021 ◽  
pp. 036119812110398
Author(s):  
Mohamed El-Agroudy ◽  
Hatem Abou-Senna ◽  
Essam Radwan
Keyword(s):  
Performance Measures ◽  
Magic Bullet ◽  
Low Density ◽  
The Novel ◽  
Review Of The Literature ◽  
Modal Interactions ◽  
New Approach ◽  
Novel Interactions ◽  
Alternative Scenarios ◽  
Urban Characteristics

In the case of the low-density city, empirical evidence continuously demonstrates that transit investment is not a magic bullet. Desirable outcomes are not guaranteed and are often dependent on development density and other urban characteristics. Mobility-as-a-service (MaaS) presents a new approach: a digital platform providing access to multi-modal travel alternatives and totally comprehensive integrated trip-making, planning, and payment services. Review of the literature highlights shortcomings in traditional transportation planning by examining aspects of multi-modal planning such as adoption, parterships, operations, integration, capacity implications, and impact analyses. To enhance the practice of multi-modal planning, the following experiment evaluates various performance measures and inter-modal interactions on International Drive in Orlando, Florida, U.S., via D- and I-optimal experimental designs in a simulated MaaS network. Alternative scenarios are developed comparing varied modal shares across five travel modes: personal vehicles, transit, ridesourcing (or ride-hailing), micro-mobility, and walking. The modal effects are analyzed to highlight the strengths and weakness of each mode under a variety of congestion conditions. While transit enjoys the lowest impact per person, ridesourcing demonstrates adverse effects across all measures. Based on the novel interactions of transit and ridesourcing with directional demand, strategies are outlined for optimizing ridesourcing-transit integration to reduce route travel time, queuing, and overall network delay. The performance impacts of curbside facilities are also discussed for improved multi-modal integration at the street level. These findings are applied to propose a framework for effective planning and implementation of mobility services in low-density cities, focused on operations, city-level connectivity, and curbside management.

Experimental Investigation of the Influence of Flow Obstacles on Post-Dryout Heat Transfer in an Annulus

2009 ◽  
Author(s):  
I. G. Anghel ◽  
H. Anglart ◽  
S. Hedberg ◽  
S. Rydstro¨m
Keyword(s):  
Heat Transfer ◽  
Current Approach ◽  
Experimental Setup ◽  
Royal Institute ◽  
Considerable Influence ◽  
Transfer Enhancement ◽  
Transient Conditions ◽  
Accuracy Of Measurements ◽  
Present Design ◽  
Institute Of Technology

This paper describes the experimental setup, instrumentation and procedures which have been developed in the thermal-hydraulic laboratory at the Royal Institute of Technology (KTH), Stockholm, Sweden, to perform new post-dryout heat transfer investigations in an annulus with flow obstacles. Previous investigations performed in the same laboratory indicated that flow obstacles had a considerable influence on the post-CHF heat transfer. The measured heat transfer enhancement was significantly under-predicted by existing models. However, the net effect of obstacles could not be deduced from the measurements, since reference - obstacle-free measurements - had not been performed. In addition, the number of thermocouples that could be installed inside the heated rod was limited to 8. These deficiencies have been removed in the current approach. Firstly, the present design of the test section allows for measurements both with and without flow obstacles. In this way the net effect of the obstacles will be captured. Secondly, a newly developed technique allowed the installation of 40 thermocouples inside of the heated rod. An additional 40 thermocouples have been installed on the external wall of the heated tube. Therefore, a significant improvement of the accuracy of measurements can be expected. The present arrangement of instrumentation is suitable to perform measurements of heat transfer under both steady-state and transient conditions.

scholarly journals Ultrasonic Non-Destructive  Testing of Fibre Reinforced  Composites

2021 ◽  
Author(s):  
◽  
Matthew Thomson
Keyword(s):  
Experimental Work ◽  
Rayleigh Waves ◽  
Ultrasonic Waves ◽  
Reinforced Composites ◽  
Surface Cracks ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Reinforced Composite ◽  
Non Destructive ◽  
Fibre Reinforced Composites

<p>This thesis focuses on the application of high frequency ultrasound as a tool for performing non-destructive testing for pultruded fibre reinforced composite (FRC) rods. These composite rods are popular in the manufacturing, construction and electrical industries due to their chemical, electrical and strength properties. Such FRCs are manufactured on automated production lines that operate day and night. Non-destructive testing techniques are desired to quickly and accurately detectmanufacturing flaws such as coating thickness irregularities and surface cracks. Layers and cracks can present as large changes in acoustic impedance and will strongly reflect ultrasonic waves. Combined with their low cost, east of use and absense of potentially harmful radiation, ultrasound has proven popular worldwide for Non-Destructive Testing. Finite Element Analysis (FEA) was employed to investigate the propagation of ultrasonic waves through layers of material to simulate a thickness measurement and the ability of ultrasound to measure thicknesses was proven. Experimental work was conducted on two fibre reinforced composite samples with varying thickness coatings of plastic and paint. The thickness was measured accurately using immersion transducers at 50MHz and a resolution of 20μm was attained through the use of matched filtering techniques. Surface acoustic waves, particularly Rayleigh waves were investigated using FEA techniques so that the generation, scattering and detection of such waves was understood. This lead to the development of methods for detecting surface cracks in glass using Rayleigh waves and these methods were successfully used in experimental work. Wave propagation in fibre reinforced composites was modelled and experimentally investigated with the results confirming theoretical expectations. Finally a Rayleigh wave was launched onto a fibre reinforced composite sample however the amount of energy leakage into the water was so great, due to the acoustic impedance of water, the detection of the wave was prevented. The conclusion reached was that an immersion setup was not appropriate for launching a travelling Rayleigh wave.</p>

Novel Methods for High-Cycle Fatigue Life Determination

2019 ◽  
Vol 810 ◽  
pp. 40-45
Author(s):  
Pavel Konopík ◽  
Radek Procházka ◽  
Martin Rund ◽  
Jan Džugan
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Testing Methods ◽  
Destructive Testing ◽  
New Approach ◽  
Constant Loading ◽  
Thermographic Analysis ◽  
Novel Methods

In the present paper, two novel methods for determining the fatigue limit are presented. Despite the fact that these methods are different in principle, both represent a new approach to testing where the main benefit is reduced consumption of material. The first method is based on small round specimens and can be considered as one of semi-destructive testing methods. The second method is based on infrared thermographic analysis and requires only one specimen. Results obtained with these techniques were compared with those obtained from standard high-cycle force-controlled fatigue tests under constant loading until failure.

A Novel Perspective in the Design of Cable-Driven Systems

2008 ◽  
Author(s):  
Giulio Rosati ◽  
Damiano Zanotto
Keyword(s):  
Systems Design ◽  
The Novel ◽  
End Effector ◽  
New Approach ◽  
Driven Systems ◽  
Working Space ◽  
Novel Approach ◽  
Workspace Analysis ◽  
Workspace Optimization ◽  
Novel Design

This paper deals with a novel approach to the design of cable-driven systems. This kind of robots possesses several desirable features that distinguish them from common manipulators, such as: low-inertia, cost-effectiveness, safety, easy reconfiguration and transportability. One key-issue that arises from the unilateral actuation is the design for workspace optimization. Most previous researches on cable-driven systems design focused their attention on workspace analysis for existing devices. Conversely, we introduce a new approach for improving workspace by design, introducing movable pulley-blocks rather than increasing the number of cables. By properly moving the pulley-blocks, the end-effector can be always maintained in the best part of the working space, thus enhancing robot capabilities without the need for additional cables. Furthermore, the eventuality of cable interference is strongly reduced. In this paper, the novel design concept is applied to different planar point-mass cable-driven robots, with one or more translating pulley-blocks. The maximum feasible isotropic force, along with the power dissipation and the effective mass at the end-effector are employed to compare the performances of different configurations.

A Predictive Ignition Delay Correlation Under Steady-State and Transient Operation of a Direct Injection Diesel Engine

2003 ◽  
Vol 125 (2) ◽  
pp. 450-457 ◽  
Author(s):  
D. N. Assanis ◽  
Z. S. Filipi ◽  
S. B. Fiveland ◽  
M. Syrimis
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Ignition Delay ◽  
Direct Injection ◽  
Thermodynamic Simulation ◽  
Injection Pressure ◽  
Transient Operation ◽  
Load Spectrum ◽  
Two Phase ◽  
Transient Conditions

Available correlations for the ignition delay in pulsating, turbulent, two-phase, reacting mixtures found in a diesel engine often have limited predictive ability, especially under transient conditions. This study focuses on the development of an ignition delay correlation, based on engine data, which is suitable for predictions under both steady-state and transient conditions. Ignition delay measurements were taken on a heavy-duty diesel engine across the engine speed/load spectrum, under steady-state and transient operation. The dynamic start of injection was calculated by using a skip-fire technique to determine the dynamic needle lift pressure from a measured injection pressure profile. The dynamic start of combustion was determined from the second derivative of measured cylinder pressure. The inferred ignition delay measurements were correlated using a modified Arrhenius expression to account for variations in fuel/air composition during transients. The correlation has been compared against a number of available correlations under steady-state conditions. In addition, comparisons between measurements and predictions under transient conditions are made using the extended thermodynamic simulation framework of Assanis and Heywood. It is concluded that the proposed correlation provides better predictive capability under both steady-state and transient operation.

A NEW APPROACH OF THE 2-AXES PAM ROBOT ARM IDENTIFICATION USING NEURAL MIMO NARX MODEL

2013 ◽  
Vol 22 (01) ◽  
pp. 1250039
Author(s):  
HO PHAM HUY ANH ◽  
KYOUNG KWAN AHN
Keyword(s):  
Learning Algorithm ◽  
Back Propagation ◽  
Training Data ◽  
The Novel ◽  
Robot Arm ◽  
New Approach ◽  
Identification Process ◽  
Highly Nonlinear ◽  
Model Scheme ◽  
Narx Model

In this paper, a novel MIMO Neural NARX model is used for simultaneously modeling and identifying both joints of the 2-axes PAM robot arm's inverse and forward dynamic model. The highly nonlinear cross effect of both links of the 2-axes PAM robot arm are thoroughly modeled through an Inverse and Forward Neural MIMO NARX Model-based identification process using experimental input-output training data. Consequently the proposed Inverse and Forward Neural MIMO NARX model scheme of the nonlinear 2-axes PAM robot arm has been investigated. The results show that the novel Inverse and Forward Neural MIMO NARX Model trained by Back Propagation learning algorithm yields outstanding performance and perfect accuracy.

Damage Detection for Simply Supported Beams Using Mid-Span Displacement Indicator

2010 ◽  
Vol 29-32 ◽  
pp. 1532-1536
Author(s):  
S.J. Zhang ◽  
Z.J. Ma
Keyword(s):  
Damage Detection ◽  
Direct Relationship ◽  
Cost Effective ◽  
Small Region ◽  
The Novel ◽  
New Approach ◽  
Simply Supported ◽  
Detection Approach ◽  
Damaged Beams ◽  
Local Stiffness

This paper investigates the detection of damage for simply supported beams to ensure their safety. Based on the analysis of possible kinds of damage may occur, this paper presents a new approach which relies on the fact that any change in local stiffness caused by damage can be reflected by the change of mid-span displacement between the intact and damaged beams. Direct relationship between the change in local stiffness and the measured mid-span displacement values is developed. This approach can identify the geometric locations of damage and then inspection means are used as a complement to find the real damage phenomena within the obtained small region. A numerical example is given to illustrate the feasibility and the effectiveness of the approach. The novel content offered by authors provides a simple, convenient, cost-effective, and nondestructive damage detection approach for simply supported beams.

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