Thermodynamic Effects on Cavitation in Water and Cryogenic Fluids

2010 ◽  
Author(s):  
Maria Grazia De Giorgi ◽  
Maria Giovanna Rodio ◽  
Antonio Ficarella
Keyword(s):  
High Speed ◽  
Time Series Data ◽  
Cold Water ◽  
Hot Water ◽  
Series Data ◽  
Cryogenic Fluid ◽  
Low Frequencies ◽  
Pixel Intensity ◽  
Cavitation Phenomenon ◽  
Optical Visualization

The present study focuses on the formation of cavitation in cold and hot water and in cryogenic fluid, characterized by strong variations in fluid properties caused by a change in temperature. Cavitation phenomenon is investigated in water and nitrogen flows in a convergent-divergent nozzle through pressure measurements and the optical visualization method. High-speed photographic recordings have been made, the cavitation phenomena evolution and the related frequency content are investigated by means of pixel intensity time series data. The results obtained concur with those obtained with the spectral analysis of the pressure signals. In the case of cryogenic fluid frequency peaks are shifted towards lower frequencies, with respect to cold water and the magnitude of the signal rises, in particular at low frequencies, for nitrogen and hot water. This can be due to thermal effects that contribute also to the low frequencies in the case of cryogenic fluid. To verify the validity of this assumption, a simple model based on the resolution of Rayleigh equation is used.

scholarly journals Development of a wind turbine gearbox virtual load sensor using multibody simulation and artificial neural networks

2021 ◽  
Author(s):  
Baher Azzam ◽  
Ralf Schelenz ◽  
Björn Roscher ◽  
Abdul Baseer ◽  
Georg Jacobs
Keyword(s):  
Time Series ◽  
Wind Turbine ◽  
High Speed ◽  
Time Series Data ◽  
Development Trend ◽  
Series Data ◽  
Ann Model ◽  
Wind Turbine Gearbox ◽  
Virtual Sensor ◽  
Artificial Neural

AbstractA current development trend in wind energy is characterized by the installation of wind turbines (WT) with increasing rated power output. Higher towers and larger rotor diameters increase rated power leading to an intensification of the load situation on the drive train and the main gearbox. However, current main gearbox condition monitoring systems (CMS) do not record the 6‑degree of freedom (6-DOF) input loads to the transmission as it is too expensive. Therefore, this investigation aims to present an approach to develop and validate a low-cost virtual sensor for measuring the input loads of a WT main gearbox. A prototype of the virtual sensor system was developed in a virtual environment using a multi-body simulation (MBS) model of a WT drivetrain and artificial neural network (ANN) models. Simulated wind fields according to IEC 61400‑1 covering a variety of wind speeds were generated and applied to a MBS model of a Vestas V52 wind turbine. The turbine contains a high-speed drivetrain with 4‑points bearing suspension, a common drivetrain configuration. The simulation was used to generate time-series data of the target and input parameters for the virtual sensor algorithm, an ANN model. After the ANN was trained using the time-series data collected from the MBS, the developed virtual sensor algorithm was tested by comparing the estimated 6‑DOF transmission input loads from the ANN to the simulated 6‑DOF transmission input loads from the MBS. The results show high potential for virtual sensing 6‑DOF wind turbine transmission input loads using the presented method.

scholarly journals The Effect of Thermo-Mechanical Processing on Physical Properties of Processed Amaranth and Oat Bran Composites

2017 ◽  
Vol 6 (2) ◽  
pp. 82
Author(s):  
Sean X. Liu ◽  
Diejun Chen ◽  
George E. Inglett ◽  
Jingyuan Xu
Keyword(s):  
Physical Properties ◽  
High Speed ◽  
Functional Foods ◽  
Cold Water ◽  
Essential Amino Acids ◽  
Hot Water ◽  
Blood Cholesterol ◽  
Gluten Free ◽  
Oat Bran ◽  
Amaranth Flour

Amaranth-oat composites were developed using gluten free amaranth flour containing essential amino acids and minerals with oat products containing β-glucan, known for lowering blood cholesterol. Amaranth flour and oat bran concentrate (OBC) composites (1:4) were processed using different technologies, including dry mixing, baking, steaming, cold wet blending, and high speed homogenizing (Polytron PT6000) with cold water or hot water. The results showed that water holding capacities, pasting, and rheological properties were dramatically increased by wet blending, Polytron with cold water, and Polytron with hot water followed by drum drying. The processing procedures created dissimilar physical properties that will enhance the application of ancient grains and oat for functional foods that are suitable for people who are gluten-intolerant. In addition, the dietary fiber contents of composites were increased by the incorporation of OBC. The composites can be inexpensively prepared and processed. The new healthful products will be affordable for people who suffer from celiac disease or gluten-intolerant. These innovative gluten-free functional food products will help millions of gluten sensitive consumers enjoy heart-healthy functional foods.

scholarly journals Time series data measurement on electricity consumption for selected domestic appliances in typical terrace house of Malaysia

2019 ◽  
Vol 8 (3) ◽  
pp. 1144-1153
Author(s):  
Naja Aqilah ◽  
Sheikh Ahmad Zaki Shaikh Salim ◽  
Aya Hagishima ◽  
Nelidya Md Yusoff ◽  
Fitri Yakub
Keyword(s):  
Time Series Data ◽  
Electricity Consumption ◽  
Hot Water ◽  
Series Data ◽  
Small Contribution ◽  
Washing Machine ◽  
Air Conditioners ◽  
Power Characteristics ◽  
Data Measurement ◽  
Domestic Appliances

This paper describes the pattern of electricity consumption from total and selected domestic appliances at a typical terrace house in Malaysia. The measured appliances can be classified into four groups on the basis of pattern of use which are ‘standby’ (TV), ‘active’ (massage chair, charger of hand phone, laptop and power bank, washing machine, air-conditioners, iron, standing fan, shower heaters, rice cooker, toaster, microwave), ‘cold’ (refrigerator) and ‘cold and hot’ (water dispenser). The major contribution of monthly electricity consumption comes from ‘cold’ appliances that consume 118.8 kWh/month followed by ‘active’ appliances that consume 87.8 kWh/month and ‘cold and hot’ appliance with 52.5 kWh/month. ‘Standby’ appliances shown a small contribution to the total electricity with 0.9 kWh/month. The amount of energy consumed depends on time-of-use, power characteristics of particular appliances as well as occupancy period.

scholarly journals An Empirical Analysis of Energy Consumption, FDI and High Quality Development Based on Time Series Data of Zhejiang Province

2020 ◽  
Vol 17 (9) ◽  
pp. 3321
Author(s):  
Shaolong Zeng ◽  
Yiqun Liu ◽  
Junjie Ding ◽  
Danlu Xu
Keyword(s):  
Time Series ◽  
Economic Development ◽  
Energy Consumption ◽  
Open Economy ◽  
High Speed ◽  
Time Series Data ◽  
Rapid Development ◽  
Series Data ◽  
High Quality ◽  
The Relationship

This paper aims to identify the relationship among energy consumption, FDI, and economic development in China from 1993 to 2017, taking Zhejiang as an example. FDI is the main factor of the rapid development of Zhejiang’s open economy, which promotes the development of the economy, but also leads to the growth in energy consumption. Based on the time series data of energy consumption, FDI inflow, and GDP in Zhejiang from 1993 to 2017, we choose the vector auto-regression (VAR) model and try to identify the relationship among energy consumption, FDI, and economic development. The results indicate that there is a long-run equilibrium relationship among them. The FDI inflow promotes energy consumption, and the energy consumption promotes FDI inflow in turn. FDI promotes economic growth indirectly through energy consumption. Therefore, improving the quality of FDI and energy efficiency has become an inevitable choice to achieve the transition of Zhejiang’s economy from high speed growth to high quality growth.

Optimizing models for remotely estimating primary production in Antarctic coastal waters

2000 ◽  
Vol 12 (1) ◽  
pp. 20-32 ◽  
Author(s):  
H.M. Dierssen ◽  
M. Vernet ◽  
R.C. Smith
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Coastal Waters ◽  
Time Series Data ◽  
Cold Water ◽  
Water System ◽  
Environmental Parameters ◽  
Day Length ◽  
Series Data ◽  
Phytoplankton Productivity

Primary productivity and associated biogeochemical fluxes within the Southern Ocean are globally significant, sensitive to change and poorly known compared to temperate marine ecosystems. We present seasonal time series data of chlorophyll a, primary productivity and in-water irradiance measured in the coastal waters of the Western Antarctica Peninsula and build upon existing models to provide a more optimum parameterization for the estimation of primary productivity in Antarctic coastal waters. These and other data provide strong evidence that bio-optical characteristics and phytoplankton productivity in Antarctic waters are different from temperate waters. For these waters we show that over 60% of the variability in primary production can be explained by the surface chlorophyll a concentration alone, a characteristic, which lends itself to remote sensing models. If chlorophyll a concentrations are accurately determined, then the largest source of error (13–18%) results from estimates of the photoadaptive variable (PBopt). Further, the overall magnitude of PBopt is low (median 1.09 mg C mg chl−1 h−1) for these data compared to other regions and generally fits that expected for a cold water system. However, the variability of PBopt over the course of a season (0.4 to 3 mg C mg chl−1 h−1) is not consistently correlated with other possible environmental parameters, such as chlorophyll, sea surface temperature, incident irradiance, day length, salinity, or taxonomic composition. Nonetheless, by tuning a standard depth-integrated primary productivity model to fit representative PBopt values and the relatively uniform chlorophyll-normalized production profile found in these waters, we can improve the model to account for approximately 72–73% variability in primary production both for our data as well as for independent historic Antarctic data.

scholarly journals Experimental Investigation of Aerodynamic Characteristics of Bat Carcasses after Collision with a Wind Turbine

2019 ◽  
Author(s):  
Shivendra Prakash ◽  
Corey D. Markfort
Keyword(s):  
Drag Coefficient ◽  
High Speed ◽  
Wind Farm ◽  
Time Series Data ◽  
Aerodynamic Drag ◽  
Turbine Blades ◽  
Wind Farms ◽  
Measured Data ◽  
Series Data ◽  
Ballistic Model

Abstract. Large number of bat fatalities have been reported in wind energy facilities in different parts of the world. The wind farm regulators are required to monitor the bat fatalities by conducting carcass survey in the wind farms. Previous studies have implemented ballistic model to characterize the carcass fall zone after strike with turbine blades. Ballistic model contains the aerodynamic drag force term which is dependent upon carcass drag coefficient. The bat carcass drag coefficient is highly uncertain and of which no measurement is available. This manuscript introduces a new methodology for bat carcass drag coefficient estimation. Field investigation at Macksburg wind farm resulted in the discovery of three bat species: Eastern Red bat (Lasiurus borealis), Hoary bat (Lasiurus cinereus) and Evening bat (Nycticeius humeralis). Carcass drop experiments were performed from a dropping platform at finite height and carcass position time series data was recorded using a high-speed camera. Falling carcasses were subjected to aerodynamic drag and gravitational force. Carcasses were observed to undergo rotation; often rotating around multiple axes simultaneously and lateral translation. The carcass complex fall dynamics along with drop from limited height prohibits it from attaining the terminal velocity. Under this limitation, drag coefficient can be estimated by fitting ballistic model to the measured data. A new multivariable optimization algorithm was performed to find the best-fit of the ballistic model to the measured data resulting in an optimized drag coefficient estimate. Sensitivity analysis demonstrated significant variation in drag coefficient with small a change in initial position highlighting the chaotic nature of carcass fall dynamics. Based on the limited sampling, the bat carcass drag coefficient range was found to be between 0.70–1.23.

TSCache

2021 ◽  
Vol 14 (13) ◽  
pp. 3253-3266
Author(s):  
Jian Liu ◽  
Kefei Wang ◽  
Feng Chen
Keyword(s):  
Time Series ◽  
High Speed ◽  
Time Series Data ◽  
Low Cost ◽  
Series Data ◽  
Efficient System ◽  
Indexing Structure ◽  
System Solution ◽  
Challenges And Opportunities ◽  
Cache System

Time-series databases are becoming an indispensable component in today's data centers. In order to manage the rapidly growing time-series data, we need an effective and efficient system solution to handle the huge traffic of time-series data queries. A promising solution is to deploy a high-speed, large-capacity cache system to relieve the burden on the backend time-series databases and accelerate query processing. However, time-series data is drastically different from other traditional data workloads, bringing both challenges and opportunities. In this paper, we present a flash-based cache system design for time-series data, called TSCache . By exploiting the unique properties of time-series data, we have developed a set of optimization schemes, such as a slab-based data management, a two-layered data indexing structure, an adaptive time-aware caching policy, and a low-cost compaction process. We have implemented a prototype based on Twitter's Fatcache. Our experimental results show that TSCache can significantly improve client query performance, effectively increasing the bandwidth by a factor of up to 6.7 and reducing the latency by up to 84.2%.

Two-frequency excitation of single-mode Faraday waves

2015 ◽  
Vol 764 ◽  
pp. 538-571 ◽  
Author(s):  
W. Batson ◽  
F. Zoueshtiagh ◽  
R. Narayanan
Keyword(s):  
Degrees Of Freedom ◽  
Time Series Data ◽  
Single Frequency ◽  
Series Data ◽  
Nonlinear Phenomena ◽  
Nonlinear Behaviour ◽  
Faraday Waves ◽  
Low Frequencies ◽  
Axisymmetric Mode ◽  
Frequency Excitation

AbstractThe purpose of this work is to investigate, for the first time, excitation of Faraday waves in small containers using two commensurate frequencies. This spatial restriction, which is encountered at low frequencies, leads to a wave composed primarily of one spatial eigenmode of the container. When two frequencies are used, the mode resonates primarily with one frequency, while the role of the second is to alter the instability threshold and the resulting nonlinear dynamics. As the parameter space expands greatly as a result of the introduction of three new degrees of freedom, viz. the frequency, amplitude and phase of the new component, the linear theory is first used as a guide to highlight basic two-frequency phenomena. These predictions and nonlinear phenomena are then studied experimentally with the system of Batson, Zoueshtiagh & Narayanan (J. Fluid Mech., vol. 729, 2013, pp. 496–523), who studied single-frequency excitation of different modes in a cylindrical cell. The two-frequency experiments of this work focus on excitation of the fundamental axisymmetric mode, and are quantitatively compared to the model via a posteriori Fourier decomposition of the parametric input. In doing so, experimental dependence of the instability on the new degrees of freedom is demonstrated, in accordance with the model predictions. This is done for a variety of frequency ratios, and overall agreement between the observed and predicted onset conditions is identical to that already reported for the single-frequency experiment. For each frequency ratio, the nonlinear behaviour is experimentally characterized by bifurcation and time series data, which is shown to differ significantly from comparable single-frequency excitations. Finally, we present and discuss a wave in which both temporal frequencies are used to simultaneously excite different spatial modes.

scholarly journals FIKWater: A Water Consumption Dataset from Three Restaurant Kitchens in Portugal

Data ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 26
Author(s):  
Lucas Pereira ◽  
Vitor Aguiar ◽  
Fábio Vasconcelos
Keyword(s):  
Water Demand ◽  
Time Series Data ◽  
Cold Water ◽  
Low Cost ◽  
Sampling Frequency ◽  
Research Community ◽  
Series Data ◽  
Flow Meters ◽  
The Internet Of Things ◽  
Size Data

With the advent of the Internet of Things (IoT) and low-cost sensing technologies, the availability of data has reached levels never imagined before by the research community. However, independently of their size, data are only as valuable as the ability to have access to them. This paper presents the FIKWater dataset, which contains time series data for hot and cold water demand collected from three restaurant kitchens in Portugal for consecutive periods between two and four weeks. The measurements were taken using ultrasonic flow meters, at a sampling frequency of 0.2 Hz. Additionally, some details of the monitored spaces are also provided.

scholarly journals Biomechanical factor affecting Baseball Pitching Velocity

2019 ◽  
Author(s):  
Yasushi Ota ◽  
Ryoga Kuriyama
Keyword(s):  
High Speed ◽  
Time Series Data ◽  
Three Dimensional ◽  
The Body ◽  
Lower Limbs ◽  
Whole Body ◽  
Series Data ◽  
Physical Factors ◽  
Body Parts ◽  
Joint Force

In baseball, pitchers have a central role and high-speed pitching is desirable. So far, several studies of the physical factors related to pitching form with the aim of improving the speed of pitched balls have been conducted. In this study, we used a motion capture to acquire three-dimensional (3D) time series data related to the speed of pitched balls and performed a kinetics analysis by using these acquired data. The acquired data were divided into five pitching phases: wind up, early cocking, late cocking, acceleration, and follow through. Our analysis identified the body parts that contribute to increasing the speed of pitched balls, i.e., the speed of rotation of individual joints and the timing/phase when power can be applied. Especially, by examining joint angular velocity and joint force, we showed that the speed of pitched balls is determined by the action of the upper limbs as well as the coordinated action of the whole body, particularly the lower limbs and the trunk.

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