Design of a 2D Electrostatic-Thermal Actuated MEMS Mirror

2008 ◽  
Author(s):  
Francesco Braghin ◽  
Elisabetta Leo ◽  
Ferruccio Resta
Keyword(s):  
Dominant Role ◽  
Vertical Axis ◽  
Optical Switches ◽  
Vibration Modes ◽  
Planar Surface ◽  
Reduced Dimensions ◽  
Supporting Frame ◽  
The Cost ◽  
Incoming Light ◽  
2D Array

MOEMS (Micro-Opto-Electro-Mechanical System) are MEMS in which the optical part plays a dominant role. MOEMS are usually used to deflect and/or focus light from/on a given spot thus acting as optical switches. Now, imagine to have a 2D array of optical switches (e.g. a CCD) and to rotate the MOEMS so that the incoming light is focused subsequently on each of these switches. What you have designed is a 2D scanner. If you reverse the process (i.e. one light source and the MOEMS projecting on a screen) you have designed a projector. The main advantage of a MOEMS projector and/or scanner are the reduced dimensions/weight with respect to traditional projectors and scanners and the fact that the necessity of optical lenses is greatly reduced thus reducing the cost of the system. In the present paper, a 2D MOEMS projector/scanner is designed. The peculiarity of the system is that the MOEMS mirror is able to rotate around two perpendicular axes having only one excitation point instead of two thus allowing to design a system that can be produced from a planar surface. This is achieved by applying the excitation to the micro-mirror indirectly through a supporting frame that is free to rotate around an eccentric vertical axis. The micro-mirror, instead, is free to rotate around an eccentric horizontal axis with respect to such supporting frame (figure 3). To be able to excite the motion of the micro-mirror along two perpendicular axes, the actuation force has to be applied in a point that is not nodal for any of the two rigid vibration modes of the system, has to be biharmonic and, to increase displacements, has to have frequencies that correspond to the two rigid eigenfrequencies of the micro-mirror.

Numerical Investigation of the Effect of Balancing-Hole on the Axial Force of a Partial Emission Pump

2014 ◽  
Author(s):  
Zhang Lisheng ◽  
Jiang Jin ◽  
Xiao Zhihuai ◽  
Li Yanhui
Keyword(s):  
Axial Force ◽  
Stokes Equations ◽  
Dominant Role ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Design Parameters ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd ◽  
The Cost

In this paper numerical simulations were conducted to analyze the effects of design parameters and distribution of balancing-hole on the axial-force of a partial emission pump. The studied pump is a single stage pump with a Barske style impeller. Based on the original impeller, we designed 7 pumps with different balancing-hole diameters and the partial emission pump equipped with different impellers were simulated employing the commercial computational fluid dynamics (CFD) software Fluent 12.1 to solve the Navier-Stokes equations for three-dimensional steady flow. A sensitivity analysis of the numerical model was performed with the purpose of balancing the contradiction of numerical accuracy and the cost of calculation. The results showed that, with increasing of the capacity, the axial force varies little. The diameter of the inner balancing-hole plays a dominant role of reducing axial-force of partial emission pump, the axial-force decreases with increasing of inner balancing-hole diameter on the whole range of operation, the axial-force of impeller without inner balancing-hole is approximately 3 times larger than that of impeller with inner balancing-hole. While the diameter of outer balancing-hole has a reverse effects compared with that of inner balancing-hole. With increasing of outer balancing-hole, the axial force increases accordingly.

scholarly journals Variable Size Twin-Rotor Wind Turbine

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2543 ◽  
Author(s):  
Piotr Doerffer ◽  
Krzysztof Doerffer ◽  
Tomasz Ochrymiuk ◽  
Janusz Telega
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Efficient Operation ◽  
Turbine Efficiency ◽  
Small Wind Turbines ◽  
Strong Winds ◽  
New Feature ◽  
The Cost ◽  
Twin Rotor

The paper presents a new concept of a vertical axis wind turbine. The idea is focused on small wind turbines, and therefore, the dominating quality is safety. Another important necessary feature is efficient operation at small winds. This implies an application of the drag driven solution such as the Savonius rotor. The presented concept is aimed at reducing the rotor size and the cost of implementation. A new wind turbine solution, its efficiency, and functionality are described. The results of numerical simulations being a proof of the concept are reported. The simulations were followed by wind tunnel tests. Finally several prototypes were built and investigated for a longer period of time. The new wind turbine concept has undergone various testing and implementation efforts, making this idea matured, well proven and documented. A new feature, namely, the wind turbine size reduction at strong winds, or in other words, an increase in the wind turbine size at low winds is the reason why it is difficult to compare this turbine with other turbines on the market. The power output depends not only on the turbine efficiency but also on its varying size.

scholarly journals Wake of a Ducted Vertical Axis Tidal Turbine in Turbulent Flows, LBM Actuator-Line Approach

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4273 ◽  
Author(s):  
Mikaël Grondeau ◽  
Sylvain Guillou ◽  
Philippe Mercier ◽  
Emmanuel Poizot
Keyword(s):  
Turbulent Flows ◽  
Vertical Axis ◽  
Tidal Currents ◽  
Eddy Simulation ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
Vertical Axis Tidal Turbine ◽  
Ambient Turbulence ◽  
The Cost ◽  
Boltzmann Method

Vertical axis tidal turbines are devices that extract the kinetic energy from tidal currents. Tidal currents can be highly turbulent. Since ambient turbulence affects the turbine hydrodynamic, it is critical to understand its influence in order to optimize tidal farms. Actuator Line Model (ALM) combined with Large Eddy Simulation (LES) is a promising way to comprehend this phenomenon. In this article, an ALM was implemented into a Lattice Boltzmann Method (LBM) LES solver. This implementation gives good results for predicting the wake of a vertical axis tidal turbine placed into a turbulent boundary layer. The validated numerical configuration was then used to compute the wake of a real size ducted vertical axis tidal turbine. Several upstream turbulence rates were simulated. It was found that the shape of the wake is strongly influenced by the ambient turbulence. The cost-to-precision ratio of ALM-LBM-LES compared to fully resolved LBM-LES makes it a promising way of modeling tidal farms.

An analysis of the impact of draft tube modifications on the performance of a Kaplan turbine by means of computational fluid dynamics

2017 ◽  
Vol 232 (11) ◽  
pp. 1937-1952
Author(s):  
Juergen Schiffer ◽  
Helmut Benigni ◽  
Helmut Jaberg
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Draft Tube ◽  
Vertical Axis ◽  
Hydropower Plant ◽  
Construction Costs ◽  
Turbine Efficiency ◽  
Kaplan Turbine ◽  
The Cost ◽  
The Impact

Due to the low electricity prices in central Europe, cost optimisations related to all parts of a new hydropower plant have become increasingly important. In case of a run-of-river hydropower plant using a vertical axis Kaplan turbine, one of the cost drivers are the excavation works. Thus, a decisive factor for the reduction of construction costs is the minimisation of the construction depth of the elbow-type draft tube. In course of the design phase of a new hydropower plant in Austria, an analysis of the impact of draft tube modifications on the performance of the Kaplan turbine was carried out by applying computational fluid dynamics. The net head of the turbine with a diameter of D = 3.15 m accounts for Hnet = 9.00 m and the maximum discharge per unit is Qmax = 57.5 m3/s. After it was proven that there is a good agreement of the numerically calculated and experimentally measured turbine efficiency for the original turbine configuration, various draft tube designs were tested in order to find out their impact on the turbine efficiency and to analyse the sources of draft tube losses in detail. Finally, it was possible to find a new draft tube design representing a compromise of reduced construction costs and acceptable turbine efficiency.

scholarly journals OPTIMIZATION OF SOME WEAVING MACHINE PARTS DESIGN. THEORETICAL APPROACH

2021 ◽  
Vol 2021 ◽  
pp. 215-221
Author(s):  
A. Mostafa ◽  
W. Hashima ◽  
S. El-Gholmy ◽  
A. Al-Oufy ◽  
M. Hassan
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Operating Time ◽  
Research Work ◽  
Element Model ◽  
Vibration Modes ◽  
Work Study ◽  
Mechanical Factors ◽  
Machine Parts ◽  
The Cost

The factors of increasing productivity, reducing the cost and the quality improvement are the most important research concerns in weaving machinery. Increasing the effectiveness and productivity of production were achieved by increasing the operating time and efficiency of weaving looms. Thus, the manufacturers of weaving equipment attempt to minimize factors that limit production speed and production conditions. Heald frame is one of the known parts of the weaving machine that causes vibrations and noise which are important factors that influence high-speed development of looms. In this research work, study of mechanical factors (stresses and vibration) has been investigated for heald shaft. Finite element model of the heald frame was constructed to simulate different type of material. Then some important natural frequencies and vibration modes are calculated and the results. Results show a major improvement with the usage of these different material. As well as the failure of heald shaft is mainly due to friction and vibration and not due to the stresses or weight.

The Role of Internal Control in the Equity Issue Market: Evidence From Seasoned Equity Offerings

2015 ◽  
Vol 32 (3) ◽  
pp. 303-328 ◽  
Author(s):  
Xinghua Gao ◽  
Yonghong Jia
Keyword(s):  
Internal Control ◽  
Risk Premium ◽  
Dominant Role ◽  
Seasoned Equity Offerings ◽  
Equity Capital ◽  
Equity Offerings ◽  
Equity Issue ◽  
Sarbanes Oxley ◽  
The Cost

This article examines the role of internal control requirements under the Sarbanes–Oxley (SOX) Act of 2002 in firms’ cost of raising equity capital. We find that, prior to the disclosure of internal control weaknesses (ICWs), ICWs are not directly associated with underwriters’ gross spread and seasoned equity offering (SEO) underpricing. After the disclosure, however, underwriters charge a risk premium on ICW issuers, especially on those disclosing ICWs in multiple consecutive years. We also find that SEO underpricing is exacerbated by multiple-year-disclosed ICWs but not by first-timers. More notably, we find that managers play a dominant role in deciding issue size pre-disclosure, but this dominance weakens post-disclosure. Taken together, our evidence suggests that internal controls help moderate the cost of raising equity capital and that ICW disclosures have significant implications for underwriters in the equity issue market.

scholarly journals Economic justification for the use of a vertical axis wind power plant in wind conditions of Russia

2021 ◽  
Vol 24 (6) ◽  
pp. 1285-1296
Author(s):  
B. P. Khozyainov ◽  
T. N. Svistunova
Keyword(s):  
Wind Speed ◽  
Power Plant ◽  
Wind Power ◽  
Power Plants ◽  
Vertical Axis ◽  
Wind Power Plant ◽  
Wind Speeds ◽  
Economic Justification ◽  
The Cost ◽  
Natural Wind

The purpose of the study is to provide an economic justification of the application efficiency of vertical axis wind-driven power plants using the principle of differential blade drag under low natural wind speeds from 1 to 15 m/s. The estimated cost is determined by the resource-index method. Calculations are made in two stages: at the first stage a statement is compiled where the consumption of resources for the design volume of work is determined according to the state unit estimate standards collections; at the second stage a local resource estimate is made, and the resource consumption in natural units is converted to cost estimates (in the prices of 2000 year). Local estimates are made using the GRAND-SMETA software package. All costs of construction materials for the wind turbine and supporting structure were assumed at the commercial cost, which was translated to the budget cost of October 2019 using deflators. The transition indices from the prices of 2000 to the prices of 2019 are applied to the cost of materials and machinery operation (without remuneration of engine-drivers) as well as to the amount of labour remuneration for installers and engine-drivers. The cost of the installation set calculated by the strength at 20 m/s natural speed is 1643.591 thousand rubles. This allowed to determine the cost of 1 kWh, which depends on the service life and the average annual wind speed. At a wind speed of 4 m/s the cost is 7.12 rub/kWh; at a wind speed of 8 m/s it is 2.19 rub/kWh. At wind speeds from 5 m/s to 11 m/s with equal exposure time intervals, the average cost of 1 kWh will be within 3.14 rub/kWh. Conducted studies have confirmed the effective use of the proposed vertical axis wind power plant under conditions of low natural wind speeds in Russia. The installation is proved to be competitive in comparison with the traditional methods of energy generation.

scholarly journals ANALYSIS OF THE COMPETITIVENESS INCREASE OF ENERGY-EFFICIENT DESIGNS OF WIND TURBINES OF VARIOUS TYPES

2017 ◽  
pp. 42-50 ◽  
Author(s):  
Roman Albertovich Ilyin ◽  
Nickolai Dmitrievich Shishkin
Keyword(s):  
Wind Turbines ◽  
Power Supply ◽  
Wind Farms ◽  
Vertical Axis ◽  
Payback Period ◽  
Capital Investments ◽  
Horizontal Axis Wind Turbines ◽  
The Cost ◽  
Supply Systems ◽  
Specific Capital

The structural analysis of wind turbines (WT) shows that along with horizontal-axis wind turbines (HAWT) there are now widely used vertical-axis wind turbines (VAWT). Significant advantages of the combined type VAWT on the basis of wind turbines of Darrieus and Savonius make them most promising for further improvement and wide application. Power of the wind turbine depends on the angle of the vector of the wind flow to the axis of rotation of the wind motor. The presence of control systems makes the wind turbines HAWT "slow" because of long reaction. As a result, the utilization of wind energy of the powerful HAWT can be reduced to 0.15-0.25 and become lower than that of VAWT, amounting to 0.20-0.40. Calculations show that the payback period of wind turbines increases from 2 to 50 years, with the increase of specific capital investments in wind turbines from 25 000 RUB/kW to 150 000 RUB/kW (from 417 up to 2500 $/kW), reducing the cost of the displaced electricity from 2.0 RUB/kW·h to 5.0 RUB/kW·h. Specific capital investments in wind turbines with a payback period of 7.0 years should not exceed 53 000 RUB/kW (884 $/kW). It seems quite reasonable to use HAWT and VAWT of the big capacity to create wind farms connected to a centralized grid. HAWT and VAWT with capacity up to 30 kW can be used for autonomous power supply of objects remoted from the centralized power supply systems.

scholarly journals Cost Efficiency Determinants: Evidence from the Canadian Banking Industry

2019 ◽  
Vol 15 (1) ◽  
pp. 86
Author(s):  
Abayomi Oredegbe
Keyword(s):  
Technical Efficiency ◽  
Cost Efficiency ◽  
Banking Industry ◽  
Dominant Role ◽  
Scale Efficiency ◽  
Efficiency Decomposition ◽  
Cost Inefficiency ◽  
Industry Policy ◽  
The Cost ◽  
The Impact

This study examines the cost efficiency of the banking industry in Canada. Utilizing 12 years of data (i.e., 2006 to 2017), and a two-stage data envelopment analysis (DEA), it provides insight on the determinants of the industry’s cost efficiency. It finds that the industry is cost inefficient, and that it could reduce costs by 11.52 percent. The cost inefficiency is due to technical and allocative inefficiencies, with technical inefficiency playing a dominant role. The technical efficiency decomposition shows that pure technical efficiency improved, but the scale efficiency deteriorated. The analysis of the determinants of cost efficiency reveals that deposit conversion into loans, high capitalization, and managerial tolerance for increase in administrative expense drive cost efficiency. On the other hand, market power and diversification diminish cost efficiency. In addition, the impact of profitability and credit risk are inconsequential to cost efficiency. This study contributes to literature by providing insights unique to Canada. Managers in the industry, policy makers, and regulators can point to these findings as empirical evidence supporting measures aimed at increasing the industry’s competitiveness and resilience.

scholarly journals ANALYSIS OF THE EFFICIENCY OF ACOUSTIC SCREENS OF DIFFERENT DESIGNS

2021 ◽  
Vol 11 (3) ◽  
pp. 62-66
Author(s):  
Oleg G. ORLOV
Keyword(s):  
Single Layer ◽  
Vertical Axis ◽  
Metal Consumption ◽  
Noise Sources ◽  
Effective Protection ◽  
Sound Energy ◽  
Effi Ciency ◽  
Complete Absorption ◽  
Absorbing Material ◽  
The Cost

Various sources of noise in cities and ways to combat them are considered. The effi ciency of two types of acoustic screens is analyzed: single-layer and two-and three-layer. The positive and negative characteristics of various designs of existing acoustic screens are listed. A fundamentally new design of the acoustic screen is described: the panels have a ridge profi le, they are located along the vertical axis of the frame with a step at which the panels above the located ridge cover the top of the lower ridge, the outer surfaces of the panels and their end parts are made of a material that has sound-refl ecting properties, and the inner surfaces of the panels are made of sound-absorbing material. Such an acoustic screen is devoid of the disadvantages inherent in acoustic screens of other structures and is more effi cient. The considered invention allows due to the use of the ridge shape of acoustic panels: prevent the refl ection of sound energy in the direction of noise sources (a small part will be directed upwards); provide almost complete absorption of sound energy as it passes through the channels formed by the ridge panels; provide the same effective protection against noise sources located on both sides of the screen; prevent the formation of snow and ice crust on sound-absorbing surfaces, which ensures the constant eff ectiveness of the screen in diff erent seasons of the year; reduce metal consumption, which will reduce the weight of the structure without reducing its effi ciency and reduce the cost of acoustic screens.

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