scholarly journals Experimental Investigation of the Small-scale Fixed Multi-chamber OWC Device

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Mohammad Shalby ◽  
Ahmed Elhanafi ◽  
Paul Walker ◽  
David G. Dorrell ◽  
Ahmad Salah ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Scale Model ◽  
Small Scale ◽  
Test Results ◽  
Wave Condition ◽  
Power Extraction ◽  
Physical Experiments ◽  
Water Columns ◽  
Measurement Wave ◽  
Oscillating Water Columns

AbstractSea wave energy generators or converters (WECs) have the potential to become a viable technology for clean, renewable energy production. Among the WEC technologies, the oscillating water columns (OWCs) are the most common WEC devices studied. These have been studied and developed over many years. Multi-chamber oscillating water columns (MC-OWC) have the potential to have a higher energy conversion when extracting energy in mixed sea states than single-chamber devices. In the work reported in this paper, physical experiments are carried under regular wave conditions to test the wave power extraction of a fixed MC-OWC small-scale model. The Power Take-Off (PTO) of the device is simulated using orifice plates. The flow characteristics through these orifices are pre-calibrated such that the extracted power can be obtained only using the pressure measurement. Wave condition effects on the damping of the PTO of the device power extraction are addressed. The test results illustrate that the PTO system damping is critical and affects device performance.

scholarly journals Experimental bearing capacity of eccentrically loaded foundation near a slope

2019 ◽  
Vol 41 (1) ◽  
pp. 33-41
Author(s):  
Tarek Mansouri ◽  
Khelifa Abbeche
Keyword(s):  
Bearing Capacity ◽  
Scale Model ◽  
Small Scale ◽  
Test Results ◽  
Square Footing ◽  
Proportional Relation ◽  
Core Boundary ◽  
Relationship Of ◽  
Small Scale Model ◽  
Increasing Load

AbstractBased on the response of small-scale model square footing, the present paper shows the results of an experimental bearing capacity of eccentrically loaded square footing, near a slope sand bed. To reach this aim, a steel model square footing of (150 mm × 150 mm) and a varied sand relative density of 30%, 50% and 70% are used. The bearing capacity-settlement relationship of footing located at the edge of a slope and the effect of various parameters such as eccentricity (e) and dimensions report (b/B) were studied. Test results indicate that ultimate bearing capacity decreases with increasing load eccentricity to the core boundary of footing and that as far as the footing is distant from the crest, the bearing capacity increases. Furthermore, the results also prove that there is a clear proportional relation between relative densities –bearing capacity. The model test provides qualitative information on parameters influencing the bearing capacity of square footing. These tests can be used to check the bearing capacity estimated by the conventional methods.

Small Scale Model Tests of Ice Gouge in Soft Sandy Silt

2008 ◽  
Author(s):  
Ingar Stava ◽  
Per R. Nystro̸m ◽  
Normann Vikse ◽  
Ove T. Gudmestad ◽  
Pavel Liferov ◽  
...  
Keyword(s):  
Scale Model ◽  
Small Scale ◽  
Test Results ◽  
Sandy Silt ◽  
Master Thesis ◽  
Pipe Segment ◽  
The University ◽  
Soil Mound ◽  
Thesis Work ◽  
Small Scale Model

Small scale gouge tests were designed and executed at the University of Stavanger in Norway as a part of master thesis work. A box (2.5 × 2.5 m) was filled with soft sandy silt and several gouge tests were performed. The subgouge soil deformations, the soil mound dimensions and the ratio between initial and residual gouge depth were measured under varying gouge parameters. Vaneshear and T-bar tests were used to estimate soil properties. A pipe segment was buried under the gouge and strains in the pipe were monitored in some of the tests. Test results are presented in this paper, including FE simulations of some of the performed experiments.

A Simplified Approach to Estimate the Probability of Otter Board Hooking at Pipelines

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Xiaopeng Wu ◽  
Vegard Longva ◽  
Svein Sævik ◽  
Torgeir Moan
Keyword(s):  
Study Data ◽  
Scale Model ◽  
Small Scale ◽  
Test Results ◽  
Bottom Trawling ◽  
Simplified Approach ◽  
Monte Carlo Simulation Technique ◽  
Simulation Tools ◽  
Parametric Studies

Hooking events, defined as trawling gear becoming firmly “stuck” under a pipeline, rarely occur during bottom-trawling operations. However, hooking events can have detrimental consequences. There is no existing method for quantifying the hooking probability of bottom-trawling operations. In this study, an approach is proposed to quantify the trawl board hooking probability using simulation tools and statistical data. Numerical simulation use the SIMLA code to establish simplified hooking criteria. The criteria link the pipeline data to the fishing activities data, enabling the quantification of hooking probability. First, the numerical simulations of both pull-over and hooking events were compared with small-scale model test results. Reasonable agreement was reached. Based on the simulation results, simplified criteria for trawl board hooking were proposed. Finally, data from the EUROPIPE II pipeline section in the Norwegian sector were used as a case study. Data regarding free span as well as fishing activities in that region were used to obtain the statistical input. The Monte Carlo simulation technique was then used to estimate the hooking probability. Parametric studies were first performed to investigate the effects of important parameters. Then, based on the findings from the parametric studies, the hooking probability with the most reasonable parameters was estimated.

RANCANG BANGUN PERANGKAT EKSPERIMENTASI PROSES PIROLISIS BIOMASA GELOMBANG MIKRO

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Noor Fachrizal
Keyword(s):  
Large Scale ◽  
Continuous Model ◽  
Biomass Energy ◽  
Scale Model ◽  
Small Scale ◽  
Laboratory Apparatus ◽  
Liquid Form ◽  
Large Scale Model ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Biomass such as agriculture waste and urban waste are enormous potency as energy resources instead of enviromental problem. organic waste can be converted into energy in the form of liquid fuel, solid, and syngas by using of pyrolysis technique. Pyrolysis process can yield higher liquid form when the process can be drifted into fast and flash response. It can be solved by using microwave heating method. This research is started from developing an experimentation laboratory apparatus of microwave-assisted pyrolysis of biomass energy conversion system, and conducting preliminary experiments for gaining the proof that this method can be established for driving the process properly and safely. Modifying commercial oven into laboratory apparatus has been done, it works safely, and initial experiments have been carried out, process yields bio-oil and charcoal shortly, several parameters are achieved. Some further experiments are still needed for more detail parameters. Theresults may be used to design small-scale continuous model of productionsystem, which then can be developed into large-scale model that applicable for comercial use.

scholarly journals Task space adaptation via the learning of gait controllers of magnetic soft millirobots

2021 ◽  
pp. 027836492110218
Author(s):  
Sinan O. Demir ◽  
Utku Culha ◽  
Alp C. Karacakol ◽  
Abdon Pena-Francesch ◽  
Sebastian Trimpe ◽  
...  
Keyword(s):  
Human Body ◽  
Degrees Of Freedom ◽  
Bayesian Optimization ◽  
Small Scale ◽  
Soft Robots ◽  
Modeling And Control ◽  
Walking Gait ◽  
Physical Experiments ◽  
Efficient Learning ◽  
Task Environments

Untethered small-scale soft robots have promising applications in minimally invasive surgery, targeted drug delivery, and bioengineering applications as they can directly and non-invasively access confined and hard-to-reach spaces in the human body. For such potential biomedical applications, the adaptivity of the robot control is essential to ensure the continuity of the operations, as task environment conditions show dynamic variations that can alter the robot’s motion and task performance. The applicability of the conventional modeling and control methods is further limited for soft robots at the small-scale owing to their kinematics with virtually infinite degrees of freedom, inherent stochastic variability during fabrication, and changing dynamics during real-world interactions. To address the controller adaptation challenge to dynamically changing task environments, we propose using a probabilistic learning approach for a millimeter-scale magnetic walking soft robot using Bayesian optimization (BO) and Gaussian processes (GPs). Our approach provides a data-efficient learning scheme by finding the gait controller parameters while optimizing the stride length of the walking soft millirobot using a small number of physical experiments. To demonstrate the controller adaptation, we test the walking gait of the robot in task environments with different surface adhesion and roughness, and medium viscosity, which aims to represent the possible conditions for future robotic tasks inside the human body. We further utilize the transfer of the learned GP parameters among different task spaces and robots and compare their efficacy on the improvement of data-efficient controller learning.

scholarly journals Experimental Study on the Behavior of Existing Reinforced Concrete Multi-Column Piers under Earthquake Loading

2021 ◽  
Vol 11 (6) ◽  
pp. 2652
Author(s):  
Jung Han Kim ◽  
Ick-Hyun Kim ◽  
Jin Ho Lee
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Bridge Piers ◽  
Scale Model ◽  
Inertia Force ◽  
Small Scale ◽  
Lap Splice ◽  
Existing Structures ◽  
Seismic Design Code ◽  
Seismic Force

When a seismic force acts on bridges, the pier can be damaged by the horizontal inertia force of the superstructure. To prevent this failure, criteria for seismic reinforcement details have been developed in many design codes. However, in moderate seismicity regions, many existing bridges were constructed without considering seismic detail because the detailed seismic design code was only applied recently. These existing structures should be retrofitted by evaluating their seismic performance. Even if the seismic design criteria are not applied, it cannot be concluded that the structure does not have adequate seismic performance. In particular, the performance of a lap-spliced reinforcement bar at a construction joint applied by past practices cannot be easily evaluated analytically. Therefore, experimental tests on the bridge piers considering a non-seismic detail of existing structures need to be performed to evaluate the seismic performance. For this reason, six small scale specimens according to existing bridge piers were constructed and seismic performances were evaluated experimentally. The three types of reinforcement detail were adjusted, including a lap-splice for construction joints. Quasi-static loading tests were performed for three types of scale model with two-column piers in both the longitudinal and transverse directions. From the test results, the effect on the failure mechanism of the lap-splice and transverse reinforcement ratio were investigated. The difference in failure characteristics according to the loading direction was investigated by the location of plastic hinges. Finally, the seismic capacity related to the displacement ductility factor and the absorbed energy by hysteresis behavior for each test were obtained and discussed.

scholarly journals Performance Analysis on the Use of Oscillating Water Column in Barge-Based Floating Offshore Wind Turbines

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 475
Author(s):  
Payam Aboutalebi ◽  
Fares M’zoughi ◽  
Izaskun Garrido ◽  
Aitor J. Garrido
Keyword(s):  
Wind Turbines ◽  
Positive Impact ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Water Columns ◽  
Numerical Tools ◽  
Oscillating Water Columns ◽  
The Given ◽  
The Waves

Undesired motions in Floating Offshore Wind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform motions. The newly proposed barge structure aims to reduce the tower displacements and platform’s oscillations, particularly in rotational movements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to oppose the oscillatory motion of the waves. Response Amplitude Operator (RAO) is used to predict the motions of the system exposed to different wave frequencies. From the RAOs analysis, the system’s performance has been evaluated for representative regular wave periods. Simulations using numerical tools show the positive impact of the added OWCs on the system’s stability. The results prove that the proposed platform presents better performance by decreasing the oscillations for the given range of wave frequencies, compared to the traditional barge platform.

Sign in / Sign up

Export Citation Format

Share Document