Theoretical and experimental study of motion and sinking time of Saxon Bowls

2022 ◽  
Author(s):  
Jaikumar Sankar ◽  
Liu Yang
Keyword(s):  
Motion Tracking ◽  
Volumetric Flow Rate ◽  
Free Form ◽  
Motion Path ◽  
Time Interval ◽  
Flow Profile ◽  
Bernoulli’S Equation ◽  
Hole Radius ◽  
Coefficient Of Discharge ◽  
High Degree

Abstract This work focuses on investigating the time of sinking of a Saxon bowl proposed by ‘International Young Physicists’ Tournament in 2020. A quasi-static model is built to simulate the motion path of the bowl and predict the sinking time subsequently. The model assumes an open axisymmetric bowl with a hole in its base. The hole is modelled as a pipe for which the flow profile is governed by a modified Bernoulli’s equation which has a Coefficient of Discharge (C_d) added to account for energy losses. The motion of the entire bowl is assumed to be in quasi-static equilibrium for an infinitesimal time interval to calculate the volumetric flow rate through the hole. The model is used to predict the sinking times of various bowls against independent variables - hole radius, bowl dimensions, mass of bowl, mass distribution of bowl, and Coefficient of Discharge - and predict the motion path of bowls of different, axisymmetric geometries. Characterisation of C_d was done by draining a bowl filled with water and measuring the time taken to do so. Experimental verification was completed through measuring sinking times of 3D printed hemispherical bowls of the different variables in water. Motion tracking of bowls with different geometries was done using computational pixel tracking software to verify the model’s predictive power. Data from experiments for sinking time against the variables corroborate with the model to a great degree. The motion path tracked, matched the modelled motion path to a high degree for bowls of different shapes, namely a hemisphere, cylinder, frustum, and a free-form axisymmetric shape. The work is poised for an undergraduate level of readership.

Approximate Degree Reduction of NURBS Curves and Surfaces: An Integrated Approach

1994 ◽  
Author(s):  
Srinivasa P. Varanasi ◽  
Athamaram H. Soni
Keyword(s):  
Shape Control ◽  
Data Exchange ◽  
Data Transfer ◽  
Integrated Approach ◽  
Free Form ◽  
Aircraft Industry ◽  
Trimmed Surfaces ◽  
Curves And Surfaces ◽  
High Degree ◽  
Boundary Curves

Abstract Data exchange between different CAD systems usually requires conversion between different representations of free-form curves and surfaces. Also, trimmed surfaces give rise to high degree boundary curves. Accurate conversion of these forms becomes necessary for reliable data transfer. Also important is the issue of shape control, specially in the aircraft industry. The objective of this paper is to investigate conversion methods and effect of shape control on the design and choice of such methods.

scholarly journals Morphology, Stability, and Application of Lycopene Microcapsules Produced by Complex Coacervation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Glaucia A. Rocha-Selmi ◽  
Carmen S. Favaro-Trindade ◽  
Carlos R. F. Grosso
Keyword(s):  
Encapsulation Efficiency ◽  
Gum Arabic ◽  
Average Diameter ◽  
Stability Test ◽  
Free Form ◽  
Complex Coacervation ◽  
The Stability ◽  
Processing And Storage ◽  
High Degree ◽  
And Storage

The interest in lycopene has increased in recent years due to studies that associate it with the reduction in risk of developing cardiovascular diseases and cancer. However, due to its high degree of unsaturation, this carotenoid is inclined to isomerize and oxidize during processing and storage, making it difficult to use in the food industry. Microencapsulation can improve this situation, increasing its stability and making incorporation into food formulations possible. Thus, the aim of this study was to microencapsulate lycopene by complex coacervation using gelatin and gum Arabic as the encapsulating agents. The microcapsules were evaluated based on the encapsulation efficiency and their morphology and then submitted to a stability test and applied in cake making. Most of the systems studied presented spherical microcapsules with defined walls. The encapsulation efficiency values were above 90%, and the average diameter of the capsules ranged from 61 to 144 μm. The stability test showed that microencapsulation offered greater protection to the lycopene as compared to its free form. The application of nonfreeze dried coacervated microcapsules in cake making was satisfactory, but the color transference was low when freezedried coacervated microcapsules were used.

A New Method for Performance Measurement of PPV Fans for Fire Fighting Under Realistic Conditions

2020 ◽  
Author(s):  
Michael Steppert ◽  
Philipp Epple ◽  
Michael Steber ◽  
Stefan Gast
Keyword(s):  
Design Process ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Navier Stokes ◽  
Analytical Relation ◽  
Positive Pressure ◽  
Flow Rates ◽  
Free Jet ◽  
Actual Flow Rate ◽  
Coefficient Of Discharge

Abstract PPV Fans (Positive Pressure Ventilation Fans) are used in firefighting to remove smoke from a burning building, so that fire fighters can have a clear view inside the house and injured people do not have to breathe toxic smoke. This can be done by placing a PPV fan in a distance of about two meters in front of a door of the burning building. On another, carefully chosen position in the building, e. g. a window, a door or at the roof an opening has to be created, where the smoke can leave the building. The same volumetric flow rate of gas that is blown into the building by the PPV fan has to leave the building at a chosen opening. Because the gas entering the building is air and the gas leaving the building is a mixture of smoke and air, the smoke concentration in the building can be reduced. To test the performance of such PPV fans, a test building with a door in the first floor and a window in the 3rd floor has been built. To measure the volumetric flow rate of the smoke and air mixture through the window in the 3rd floor that is leaving the building, a flow meter nozzle was designed. The design process was done using the commercial Navier Stokes solver Star CCM+, where three nozzle designs, such as a nozzle with constant velocity increase, a quarter circle nozzle and a non-curved nozzle were investigated for different volumetric flow rates. Also, a rounding at the window, where the nozzle is placed, was investigated to prevent flow detachment and shock losses at the inlet of the nozzle. The volumetric flow rate through the nozzle can be calculated, by measuring the pressure at the nozzle wall (before the contraction) and applying Bernoulli’s law, the continuity equation and assuming atmospheric pressure at the free jet flow at the end of the nozzle. The so calculated volumetric flow rate was compared with the actual flow rate, given by the numerical CFD simulations. With these values, the nozzle specific coefficient of discharge for several volumetric flow rates has been calculated and a function fitting was done to get obtain analytical relation between pressure and volumetric flow rate. The detailed design process of the three nozzles, the numerical results of the CFD studies and the determination of the nozzle specific coefficients of discharge are shown and discussed in detail in this work.

The first-passage density of the Brownian motion process to a curved boundary

1992 ◽  
Vol 29 (02) ◽  
pp. 291-304 ◽  
Author(s):  
J. Durbin ◽  
D. Williams
Keyword(s):  
Brownian Motion ◽  
Brownian Bridge ◽  
Sample Path ◽  
Practical Method ◽  
Time Interval ◽  
Brownian Motion Process ◽  
First Passage ◽  
Curved Boundary ◽  
Multiple Integrals ◽  
High Degree

An expression for the first-passage density of Brownian motion to a curved boundary is expanded as a series of multiple integrals. Bounds are given for the error due to truncation of the series when the boundary is wholly concave or wholly convex. Extensions to the Brownian bridge and to continuous Gauss–Markov processes are given. The series provides a practical method for calculating the probability that a sample path crosses the boundary in a specified time-interval to a high degree of accuracy. A numerical example is given.

scholarly journals Research on Key Process Technology for Profile Electrolytic Finishing of Large Marine Propeller Impeller

2018 ◽  
Vol 25 (s2) ◽  
pp. 158-163
Author(s):  
Bi-Rong Ding ◽  
Yuan-long Chen ◽  
Ji Zhou ◽  
Pei-xuan Chen
Keyword(s):  
Manufacturing Industry ◽  
Simulation Software ◽  
Free Form ◽  
Surface Finishing ◽  
Motion Path ◽  
Machining Accuracy ◽  
Process Technology ◽  
Blade Machining ◽  
Cathode Structure ◽  
Free Form Surface

Abstract An electrolysis process method for free-form blade surface finishing is proposed for a free-form surface impeller, and a stepwise method is used to process the inter-blade channel of the overall impeller. The forming cathode is then used to finish the blade to meet the blade processing requirements. In the design, the forming cathode structure was improved by using motion simulation software, and the flow field simulation software was used to simulate and analyze the cathode flow channel. The cathode shape and the electrolyte flow rate between the electrodes meet the processing requirements. In the process of processing experiments, the motion path of the cathode was analyzed and optimized. The effect of the feed direction on the uneven distribution of the blade machining gap was reduced through optimization, and high-frequency pulse power processing was used to reduce the machining gap and improve the machining accuracy of the blade. The experimental results show that the process scheme is feasible and the precision of the processed impeller free-form surface is significantly improved. The material is a monolithic turbine disk of high-temperature alloys, and its large twisted blade processing has always been a problem in the manufacturing industry.

An Inter-Domain Agent Based Secure Authorization and Communication for Mobile Clients in Wireless AdHoc Networks

2010 ◽  
Vol 2 (3) ◽  
pp. 34-46
Author(s):  
Neeraj Kumar ◽  
R. B. Patel
Keyword(s):  
Mobile Agents ◽  
Dynamic Network ◽  
Time Interval ◽  
Network Nodes ◽  
Agent Based ◽  
Mobile Adhoc Network ◽  
Adhoc Network ◽  
Mobile Clients ◽  
Wireless Adhoc Networks ◽  
High Degree

Wireless mobile adhoc network (MANET) is a dynamic network. Nodes in a MANET have high degree of mobility from one domain to another in a particular time interval. In such a dynamic network, security is a major concern. In this paper, the authors propose an inter domain agent based secure authorization and communication for mobile clients/nodes (MCs) in MANET. Mobile agents (MAs) are software programs that support the mobility of clients in different domain and provide necessary resources to the clients for safe execution. It also shares the key with MCs in different domains. An algorithm for secure authorization and communication between MCs having mobility in different domains is proposed. The scheme is evaluated on ns-2 w.r.t. metrics such as overall cost in terms of overhead generated, admission and traceability cost, and itinerary chosen by MAs w.r.t. mobility of MCs.

Reproducibility of 24-h growth hormone profiles in children

1992 ◽  
Vol 126 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Kerstin Albertsson-Wikland ◽  
Sten Rosberg
Keyword(s):  
Time Interval ◽  
Individual Child ◽  
High Reproducibility ◽  
Normal Height ◽  
Prepubertal Children ◽  
Gh Secretion ◽  
Biological Phenomena ◽  
High Degree ◽  
Mean Time ◽  
Peak Widths

The rate of GH secretion and the pattern of GH peaks were compared in a group of nine prepubertal children during their prepubertal period in repeated 24-h GH profiles. At investigation, the children were 6–1 3 years old (at first profile 6–11 years old) and of normal height (±2 sd). Two profiles were obtained per child, (with a mean time interval of 1.5 years, range 0.7 to 3.5 years. The calculated GH secretions of the first and second profiles were compared. As a group, no significant differences in secreted amount of GH, when expressed as data from the second profile as a percentage of data from the first profile (93±8%), number of peaks (98±7%) or mean peak amplitudes (92±11%), were obtained. Between the repeated curves of an individual child, maximal difference in secretion, number of peaks and mean peak amplitudes ranged around±30%, with a mean intraindividual cv of 12%. The reproducibility in the peak distribution for all profiles was also analysed. The relative frequencies is a percentage of the GH peak amplitudes and peak widths were virtually identical in the repeated profiles. Reproducibility of the temporal pattern of profiles was analysed using time-series analysis (Fourier analysis) and showed no difference in rhythmicity between the different occasions. In conclusion, a high reproducibility of both GH secretion and GH pattern was found for the whole group of prepubertal children. The high degree of reproducibility of the 24-h GH profiles of the whole group of children indicated that the information from these curves, in terms of both pattern and total secretion, can be used for clinical as well as for physiological purposes. The intraindividual reproducibility was less pronounced, however, leading to a sound scepticism when relating biological phenomena to a single profile of an individual child.

scholarly journals Effect of Types of Weir on Discharge

2014 ◽  
Vol 5 (2) ◽  
pp. 35-40
Author(s):  
L L Caroline ◽  
Nasser R Afshar
Keyword(s):  
Flow Rate ◽  
Hydraulic Structure ◽  
Maximum Flow ◽  
Flow Mechanism ◽  
Measuring Head ◽  
Sluice Gate ◽  
Bernoulli’S Equation ◽  
Different Types ◽  
Design Requirements ◽  
Coefficient Of Discharge

 The measurement of discharge is one of the main concerns in hydraulic engineering. The study of types of weir on discharge is important as the knowledge of the accurate measurement of discharges helps in understanding of the flow mechanism as well as designing the hydraulic structures for future. Structures such as rectangular weir, vee notch weir and crump weir are placed in a channel to measure the flow rate. By using Bernoulli’s equation, weir equation are derived and used to determine the flow rate. The main objective is to determine the optimum discharge for different types of weirs. This discharge is important in designing the hydraulic structure. Overestimated discharge may cause failure to the structure and if the discharge is underestimated, it may not fulfill the design requirements. The studies are experimented from maximum flow to minimum flow by measuring head over the weir for different working sections; flat and slope of 1:2400 and different height of partially opened sluice gate of 4cm and 6cm for crump drowned condition. The result shows that the coefficient of discharge, Cd decreases when the head of water above the crest increases; except for crump weir in which Cd is independent of the head. Meanwhile, the velocities when slope is 1:2400 are higher as compared to flat.

Non-Rigid Image Registration based on Parameterized Surfaces: Application to 3D Cardiac Motion Image Analysis

2021 ◽  
pp. 2250028
Author(s):  
Said Khalid Shah
Keyword(s):  
Image Registration ◽  
Motion Tracking ◽  
Salient Feature ◽  
Ct Images ◽  
Heart Beat ◽  
Cardiac Motion ◽  
Free Form ◽  
3D Ct ◽  
Registration Accuracy ◽  
Whole Heart

This paper describes the Fast Radial Basis Function (RBF) method for cardiac motion tracking in 3D CT using non-rigid medical image registration based on parameterized (regular) surfaces. The technique is a point-based registration evaluation algorithm which does register 3D MR or CT images in real time. We first extract the surface of the whole heart 3D CT and its contrast enhanced part (left ventricle (LV) blood cavity) of each dataset with a semiautomatic contouring and a fully-automatic triangulation method followed by a global surface parameterization and optimization algorithm. In second step, a set of registration experiments are run to calculate the deformation field at various phases of cardiac motion or cycle from CT images, which results into significant deformation during each phase of a cycle. The surface points of the whole heart and LV are used to register the source systole image to various diastole target images taken at different phases during a heart beat. Our registration accuracy improves with the increase in number of salient feature points (i.e. optimized parameterized surfaces) and it has no effect on the speed of the algorithm (i.e. still less than a second). The results show that the target registration error is less than 3[Formula: see text]mm (2.53) and the performance of the Fast RBF algorithm is less than a second using a whole heart CT dataset of a single patient taken over the course of the entire cardiac cycle. At the end, the results for recovery (or analysis) of bigger deformation in heart CT images using the Fast RBF algorithm is compared to the state-of-the-art Free Form Deformation (FFD) registration technique. It is proved that the Fast RBF method is performing better in speed and slightly less accurate than the FFD (when measured in terms of NMI) due to iterative nature of the latter.

Study on Mechanical Mechanics with a Method for Minimum-Time Path Planning of Robots in Cartesian Space

2013 ◽  
Vol 703 ◽  
pp. 181-185 ◽  
Author(s):  
Xiang Rong Xu ◽  
Dong Qing Shi ◽  
Man Lu ◽  
Hao Xu ◽  
Tao Zhou
Keyword(s):  
Path Planning ◽  
Minimum Time ◽  
Motion Path ◽  
Robot Motion ◽  
Time Interval ◽  
Cartesian Coordinates ◽  
Motion Trajectories ◽  
Time Path ◽  
Cartesian Space

This paper presents an approach for robot motion path planning in Cartesian space. The motion trajectories are specified by a group of parameter equations in Cartesian coordinates. The time interval [0, is divided into m segments, and the coefficients of polynomial at each segment can be obtained in recursive form. The problem of minimum-time path planning and the determination of m are also studied.

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