scholarly journals Vibration Actuator System with Small-Scale Size Capable of Visual Inspection of Large Complex Iron Structures

2021 ◽  
Vol 11 (16) ◽  
pp. 7467
Author(s):  
Hiroyuki Yaguchi ◽  
Yusuke Itoh
Keyword(s):  
Magnetic Force ◽  
Vertical Plane ◽  
Experimental Result ◽  
Maximum Efficiency ◽  
Small Scale ◽  
Social Infrastructure ◽  
Rubber Material ◽  
Scale Size ◽  
Actuator System ◽  
Reciprocating Movement

Deterioration of social infrastructure equipment has become a major problem in countries around the world. In the present study, a novel vibration actuator system capable of movement on an iron structure having complicated surfaces, such as steps, is proposed. A vibration actuator capable of reciprocating movement with a small-scale size was prototyped and tested. In consideration of mobility, the size of the vibration actuator is designed to be smaller than 50 mm and the total mass is lighter than 20 g. The experimental result demonstrates that the maximum efficiency of the vibration actuator was 28.1%, and the maximum pulling power was 1.8 N. Furthermore, a vibration actuator system in which two vibration actuators and a wheel having a magnetic force connected by a flexible silicone rubber material was prototyped. This actuator system can move over a step of 48 mm in the horizontal plane and 25 mm in the vertical plane without control. Finally, a machine test was conducted on the frame surface moving, which is difficult even for robots. This actuator system can move at an average speed of 12.1 mm/s within the frame.

scholarly journals Ethnic face categorization by Russians and Tuvinians in discrimination tasks

2019 ◽  
Vol 12 (4) ◽  
pp. 120-141
Author(s):  
V.N. Kharitonov ◽  
I.A. Basyul ◽  
K.I. Ananyeva ◽  
N.O. Tovuu
Keyword(s):  
Task Performance ◽  
Ethnic Groups ◽  
Communication Skills ◽  
Dual Task ◽  
Maximum Efficiency ◽  
Small Scale ◽  
Isolated Populations ◽  
Face Categorization ◽  
Transition Series ◽  
Large Groups

The opposite tendencies towards blurring the boundaries of compact living of ethnic groups and of relocation of large groups of strangers into the territories of compact residence of local groups generate a number of specific phenomena connected with the inter-group perception. We conducted a comparative study of perception and communication of transition series of “ethnic faces” among two small-scale isolated populations and representatives of the corresponding ethnic groups in multi-ethnic cities. The participants were to solve two discrimination task, one individually, the AB=X task, the other one, the dual “same-different” task, in dyads. For all samples of subjects, of In the AB=X task, the maximum discrimination efficiency was recorded for the same no. 2—3 pair of transition images series This may indicate that all subjects relied on the morphological features stimulus faces than on anything else. Also a tendency is observed toward similarity in the dynamics of efficiency of task performance in different groups of subjects, with the exception of the sample of Russians from the metropolis. At the same time, in the dyadic experiment, subjects from megacities demonstrate different trends in terms of the maximum efficiency of task performance. The sample of Russian subjects from Moscow demonstrates a significantly smaller decrease in efficiency when approaching the edges of the transitional series of stimulus images in the AB=X task, but not in the dual task. This is probably due to different nature of the tasks, i.e. one may easily suppose a more developed ability to perceptually discriminate between ethnic faces resulting from their greater variety in the environment, as in Moscow megacity, whereas it does not seem reasonable to suppose difference in communication skills required to perform the dual task across the samples.

Small Scale Supercritical CO2 Radial Inflow Turbine Meanline Design Considerations

2018 ◽  
Author(s):  
Tina Unglaube ◽  
Hsiao-Wei D. Chiang
Keyword(s):  
High Velocity ◽  
Gas Turbines ◽  
Velocity Ratio ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Working Fluid ◽  
Small Scale ◽  
Optimum Velocity ◽  
Set Up ◽  
Very High

In recent years closed loop supercritical carbon dioxide Brayton cycles have drawn the attention of many researchers as they are characterized by a higher theoretic efficiency and smaller turbomachinery size compared to the conventional steam Rankine cycle for power generation. Currently, first prototypes of this emerging technology are under development and thus small scale sCO2 turbomachinery needs to be developed. However, the design of sCO2 turbines faces several new challenges, such as the very high rotational speed and the high power density. Thus, the eligibility of well-established radial inflow gas turbine design principles has to be reviewed regarding their suitability for sCO2 turbines. Therefore, this work reviews different suggestion for optimum velocity ratios for gas turbines and aims to re-establish it for sCO2 turbines. A mean line design procedure is developed to obtain the geometric dimensions for small scale sCO2 radial inflow turbines. By varying the specific speed and the velocity ratio, different turbine configurations are set up. They are compared numerically by means of CFD analysis to conclude on optimum design parameters with regard to maximum total-to-static efficiency. Six sets of simulations with different specific speeds between 0.15 and 0.52 are set up. Higher specific speeds could not be analyzed, as they require very high rotational speeds (more than 140k RPM) for small scale sCO2 turbines (up to 150kWe). For each set of simulations, the velocity ratio that effectuates maximum efficiency is identified and compared to the optimum parameters recommended for radial inflow turbines using subcritical air as the working fluid. It is found that the values for optimum velocity ratios suggested by Rohlik (1968) are rather far away from the optimum values indicated by the conducted simulations. However, the optimum values suggested by Aungier (2005), although also established for subcritical gas turbines, show an approximate agreement with the simulation results for sCO2 turbines. Though, this agreement should be studied for a wider range of specific speeds and a finer resolution of velocity ratios. Furthermore, for high specific speeds in combination with high velocity ratios, the pressure drop of the designed turbines is too high, so that the outlet pressure is beyond the critical point. For low specific speeds in combination with low velocity ratios, the power output of the designed turbines becomes very small. Geometrically, turbines with low specific speeds and high velocity ratios are characterized by very small blade heights, turbines with high specific speeds and small velocity ratios by very small diameters.

Preliminary Design of Small-Scale Supercritical CO2 Radial Inflow Turbines

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Tina Unglaube ◽  
Hsiao-Wei D. Chiang
Keyword(s):  
Optimum Design ◽  
Supercritical Co2 ◽  
Velocity Ratio ◽  
Design Procedure ◽  
Expansion Ratio ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Small Scale ◽  
Preliminary Design ◽  
Line Design

Abstract In recent years, supercritical CO2 (sCO2) Brayton cycles have drawn the attention of researchers due to their high cycle efficiencies, compact turbomachinery, and environmental friendliness. For small-scale cycles, radial inflow turbines (RIT) are the prevailing choice and one of the key components. A mean line design procedure for sCO2 RIT is developed and design space exploration conducted for a 100 kW-class turbine for a low-temperature waste-heat utilization sCO2 Brayton cycle. By varying the two design parameters, specific speed and velocity ratio, different turbine configurations are setup and compared numerically by means of computational fluid dynamics (CFD) simulations. Results are analyzed to conclude on optimum design parameters with regard to turbine efficiency and expansion ratio. Specific speeds between 0.2 and 0.5 are recommended for sCO2 RIT with small though flow (3 kg/s). The higher the velocity ratio, the bigger the turbine expansion ratio. Pairs of optimum design parameters that effectuate maximum efficiency are identified, with smaller velocity ratios prevailing for smaller specific speeds. The turbine simulation results for sCO2 are compared to well-established recommendations for the design of RIT from literature, such as the Balje diagram. It is concluded that for the design of sCO2 RITs, the same principles can be used as for those for air turbines. By achieving total-to-static stage and rotor efficiencies of 84% and 86%, respectively, the developed mean line design procedure has proven to be an effective and easily applicable tool for the preliminary design of small-scale sCO2 RIT.

The Effect of Heat Induction on Shear Strength of Soft Soil in Radial Zone

2020 ◽  
Vol 998 ◽  
pp. 329-334
Author(s):  
Maraden Panjaitan ◽  
Lawalenna Samang ◽  
Achmad Bakri Muhiddin ◽  
Tri Harianto
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Soft Soil ◽  
Soft Clay ◽  
Experimental Result ◽  
Small Scale ◽  
Infrastructure Development ◽  
Heat Induction ◽  
Vane Shear Test ◽  
Radial Zone

The main problem in infrastructure development at the soft clay was its bearing capacity therefore it needs to be improved. In this research, the improvement method was carried out by modeling in small scale of preloading and heat induction combination. Location of soft clay sampling was in Takalar, Indonesia. The purpose of this study was to investigate the change of the shear strength of soft soil corresponding with heat induction at the radial zone. The shear strength was obtained by vane shear test and compressive strength from unconfined compressive test (UCT). The heat applied ranging from 100o C, 200o C, 300o C, and 400o C with static preloading load 0.20 kg/cm2. The strengths of the soil in radial zones have been tested at R0, R1, and R2. At lowest temperature 100° at R0 the compressive strength was 0.203 kg/cm2, at highest temperature 400° at R0 the compressive strength 0.467 kg/cm2, there was a significant increasing of compressive strength value with the change of temperature. At the highest temperature 4000 the shear strength from vane shear tests resulting at R0 0.240 kg/cm2, R1 of 0.128 kg/cm2, R2 of 0.077 kg/cm2. At the lowest temperature of 100o C shows R0 at 0.116 kg/cm2, R1 at 0.070 kg/cm2, R3 of 0.046 kg/cm2. The results show a tendency of declining strength value as the soil farther away from center of heat induction. The experimental result from this model produces strength that can be used as a parameter of the foundation model on soft soil.

Resources Provision of Rural Territories Social Sphere: A Case Study

2019 ◽  
Vol 9 (7) ◽  
pp. 1512
Author(s):  
Olga RUBAEVA ◽  
Ekaterina POGARTSEVA ◽  
Ekaterina KOT ◽  
Tatyana NIKITINA
Keyword(s):  
Sustainable Development ◽  
Program Implementation ◽  
Rural Population ◽  
Numerical Data ◽  
Agricultural Products ◽  
Small Scale ◽  
Social Infrastructure ◽  
Social Sphere ◽  
Chelyabinsk Region ◽  
High Level

The article presents analysis of resources provision of social sphere of the rural territories of Chelyabinsk region; there are analyzed the main components of creature comforts of a rural population.  There is given an assessment of a program implementation of sustainable development of the rural territories of Chelyabinsk region and the country in general. There are the numerical data characterizing the delivery of Program in regions of the Russian Federation and amounts of financing for realization the actions contributing to sustainable development of the rural territories. The main directions of the Program are connected with providing the rural territories with a necessary social infrastructure sufficient for maintenance of worthy level of living of a rural population and also to promoting growth of appeal of shape of the rural territories to inflow of the human and investment equities. There is shown an international experience of achievement of high level and quality of life in the rural territories. There are determined the main priorities of development of the rural territories of the European countries: innovation in the structuring of farming; providing a continuous line of production of producing agricultural products; rational use of natural resources; improvement of social and economic conditions of life sustenance in the rural territories. There is revealed the direct dependence between ensuring growth of sustainable development level of the rural territories on degree of a scope and efficiency of use of own resources and the available potentials in the territories. Here are allocated types of the rural territories on the level of sustainable development: the territories of the advancing development; the developing territories; survival territories. There are established the reasons of decrease in life level in the rural territories and great lagging from the level of sustainable development of urban localities. The main reasons are: the concentration of production and conversion of agricultural products in certain settlements promoting desolation and irrational use of potentials of other territories; insufficient financing of the social sphere; a lack of support from the state of small-scale farmer and personal subsidiary farms. There are made recommendations about enhancement of organizational, economic and ecological opportunities of use of the available resource providing the rural territories; production organizations of agricultural products; development of a social infrastructure.

Unsteady Structure Measurement of Cloud Cavitation on a Foil Section Using Conditional Sampling Technique

1989 ◽  
Vol 111 (2) ◽  
pp. 204-210 ◽  
Author(s):  
A. Kubota ◽  
H. Kato ◽  
H. Yamaguchi ◽  
M. Maeda
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Laser Doppler Anemometry ◽  
Low Frequency ◽  
Sampling Technique ◽  
Experimental Result ◽  
Small Scale ◽  
Conditional Sampling ◽  
Cloud Cavitation ◽  
Structure Of Flow

The structure of flow around unsteady cloud cavitation on a stationary two-dimensional hydrofoil was investigated experimentally using a conditional sampling technique. The unsteady flow velocity around the cloud cavitation was measured by a Laser Doppler Anemometry (LDA) and matched with the unsteady cavitation appearance photographed by a high-speed camera. This matching procedure was performed using data from pressure fluctuation measurements on the foil surface. The velocities were divided into two components using a digital filter, i.e., large-scale (low-frequency) and small-scale (high frequency) ones. The large-scale component corresponds with the large-scale unsteady cloud cavitation motion. In this manner, the unsteady structure of the cloud cavitation was successfully measured. The experimental result showed that the cloud cavitation observed at the present experiment had a vorticity extremum at its center and a cluster containing many small cavitation bubbles. The convection velocity of the cavitation cloud was much lower than the uniform velocity. The small-scale velocity fluctuation was not distributed uniformly in the cavitation cloud, but was concentrated near its boundary.

scholarly journals Experimental Investigation of PCM Spheres in Thermal Energy Storage System

2013 ◽  
Vol 367 ◽  
pp. 228-233 ◽  
Author(s):  
N.A.M. Amin ◽  
Azizul Mohamad ◽  
M.S. Abdul Majid ◽  
Mohd Afendi ◽  
Frank Bruno ◽  
...  
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Packed Bed ◽  
Energy Storage System ◽  
Heat Transfer Fluid ◽  
Experimental Result ◽  
Small Scale ◽  
Storage Unit

This paper presents the experimental result of a small scale packed bed of random spheres with encapsulated PCM being charged and discharged. A vapor compression refrigerator and heated room with fan heater were used to supply constant heat transfer fluid at a minimum temperature of -28°C for charging and 16°C for discharging. Even though the temperature differences were not fixed in the experiments, the performance of the thermal energy storage is depicted in the form of effectiveness values. Different results were obtained for charging and discharging the thermal storage unit. The differences are expected to come from natural convection and super cooling. The super cooling during the charging process was as high as 6°C.

Estimating error in wind speed measurements for experimental fires

2001 ◽  
Vol 31 (3) ◽  
pp. 401-409 ◽  
Author(s):  
A L Sullivan ◽  
I K Knight
Keyword(s):  
Wind Speed ◽  
Small Scale ◽  
Confidence Limits ◽  
Single Measure ◽  
Rate Of Spread ◽  
Scale Size ◽  
Fire Front ◽  
Scalar Measure ◽  
Eucalypt Forests ◽  
Measured Wind Speed

Most experimental fires, by nature, are small scale ([Formula: see text]100 m), and rate of spread measurements are taken over periods of several minutes. The aim of empirical fire modellers is to ascribe a single measure of rate of forward spread over a period to a single scalar measure of wind. The actual wind affecting the fire is unmeasurable; its value must be estimated from remote anemometry. Observation and consideration of the spatial and temporal statistics of the wind has allowed confidence limits to be placed upon the accuracy with which the measured wind reflects the wind acting on the fire front. Experimental data to verify these estimates was gathered during Project Vesta, a study into high-intensity fires in dry eucalypt forests. An equation that quantifies the accuracy of the estimate of wind affecting the fire front is given. The accuracy increases with time scale, size of the fire front, and density of anemometry. When applied to a measured wind speed taken some distance from the fire, it gives a useful estimate of the likely variation of the corresponding wind at the fire front.

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