Mounting Structure Research Articles

Alignment technology of heavy ion medical machine

Heavy ion medical machine (HIMM) is built by the Institute of Modern Physics, Chinese Academy of Sciences, with a high-energy beam transport line with a height of 18 m, and its complex space mounting structure increases the difficulty of installation and alignment. The aim of this paper is to provide methods to install all accelerator components efficiently and to ensure that the alignment accuracies of all installed components are within the designed values. We accomplished the fiducialization and pre-alignment of complex modules by combining the laser tracker and the alignment telescope. By analyzing various elements that affect the accuracy of alignment, a method of alignment for high-energy beam transport line was proposed based on high-precision three-dimensional control network. All components have been installed and aligned in a short time, alignment position accuracy of magnets is less than 0.1 mm, and the treatment components alignment accuracy is no more than 0.4 mm. On the basis of error analysis, all alignment results are better than the required precisions, and all of these guaranteed the successful operation of HIMM.

New approach for maximizing generation and optimal utilization of available space for solar PV system

To accomplish an enormous demand of power with solar energy, a cost effective and optimum system has to be developed which works in synchronisation with the existing grid. The Government in developing countries like India is providing momentous opportunities and marvellous schemes to promote renewable energy sources like solar for generating power. This paper aims to analyse the generation of power from solar photovoltaic (PV) systems economically and efficiently as it is always a challenge for the design engineer to develop an economical and efficient solar PV system. Apart from technical issues, structural aspects also affect the power generation from PV modules. This paper proposes an innovative design of non-movable tracking system that enhances the power generation of PV modules by just providing two grooves in the mounting structure in place of the tracking system. A formula for the optimum space calculation for PV installation is also proposed in this paper. A comparative analysis of total annual energy generated by the hardware setup and the results obtained using software of the rooftop solar PV system has also been analysed for practical consideration. To verify the results, first, the system has been simulated using the PVSYST software considering all practical and existing realistic losses like PV loss due to irradiance and temperature, array soil loss, module quality loss, array mismatch loss, ohmic wiring loss, and inverter loss which formulate a bonafide case of consideration and then hardware implementation of the proposed system. The hardware and software results have been compared to analyse the proposed topologies adopted to address the aforesaid problems.

Solar tracker development based on a POF bundle and Fresnel lens applied to environment illumination and microalgae cultivation

Although within the group of countries with the highest solar irradiation index in the world, Brazil still underuses its natural power. Brazil’s hydropower energy today makes up 68,5% of the total energy produced, in contrast however, photovoltaic energy production is still only 0.01%. As an effort to open up new frontiers for solar energy uses, the main objective of this project was to use solar energy in form of light to reduce the power consumption required for continuously lighting any kind of environment as well as to propose a new technology for illuminating a conventional window-type photobioreactor (PBR) in the cultivation of microalgae for biofuel production in order to reduce their associated costs. The system is composed by a solar tracker, an electromechanical control, a Fresnel lens and a plastic optical fiber (POF) bundle, in which tip the lens concentrates the solar radiation. Therefore, at the other end of the bundle, the POFs can be distributed homogeneously in any local where one wants to illuminate. The solar tracker is able to track the Sun from sunrise to sunset using an algorithm whose function is to calculate the Sun position according to the local time and latitude using an equatorial mount structure. In addition, some sensors are employed for monitoring relevant parameters, for instance, the light intensity inside the POF bundle, the right ascension and declination angles of the tracker and the solar radiation. These parameters can be downloaded in real time through a specially designed mobile application. As application of the solar tracker, two projects were developed and described in this paper: two kinds of solar luminaires for illumination of internal ambiences and a closed photobioreactor by POF illumination, with nontransparent material, free of outside contamination with low cost and the study of the produced biomass through the lipid content. Both applications were compared in performance with their conventional counterparts and, as a conclusion, it is shown that in both cases they can substitute their conventional counterparts with advantages.

Development of a shoulder-mounted robot for MRI-guided needle placement: phantom study.

This paper presents new quantitative data on a signal-to-noise ratio (SNR) study, distortion study, and targeting accuracy phantom study for our patient-mounted robot (called Arthrobot). Arthrobot was developed as an MRI-guided needle placement device for diagnostic and interventional procedures such as arthrography. We present the robot design and inverse kinematics. Quantitative assessment results for SNR and distortion study are also reported. A respiratory motion study was conducted to evaluate the shoulder mounting method. A phantom study was conducted to investigate end-to-end targeting accuracy. Combined error considering targeting accuracy, respiratory motion, and structure deformation is also reported. The SNR study showed that the SNR changes only 2% when the unpowered robot was placed on top of a standard water phantom. The distortion study showed that the maximum distortion from the ground truth was 2.57%. The average error associated with respiratory motion was 1.32mm with standard deviation of 1.38mm. Results of gel phantom targeting studies indicate average needle placement error of 1.64mm, with a standard deviation of 0.90mm. Noise and distortion of the MR images were not significant, and image quality in the presence of the robot was satisfactory for MRI-guided targeting. Combined average total error, adding mounting stability errors and structure deformation errors to targeting error, is estimated to be 3.4mm with a standard deviation of 1.65mm. In clinical practice, needle placement accuracy under 5mm is considered sufficient for successful joint injection during shoulder arthrography. Therefore, for the intended clinical procedure, these results indicate that Arthrobot has sufficient positioning accuracy.

Design Criterion of Damper Component of Passive-Type Mount Module without Using Base Mass-Block

Passive-type mount modules have been used frequently to isolate excitation from the target mechanical system, and electric power plants use the mount devices to control the harmonic excitation source from a combustion engine. The mount structure is composed of a spring component, a stacked thin-panel, and a heavy base-mass block, and installation as well as maintenance of the structures are difficult. To tackle this problem associated with mount modules, I investigate in this work the feasibility of a simplified mount module with no base mass-block; the harmonic frequency of interest was selected from 30 (Hz) to 120 (Hz) owing to the constant rotating speed of the combustion engine at 1800 (rev/min). The design criterion of the damper components was formulated from the response index at the electric power plant, and the influence of the damper component at the proposed mount was calculated theoretically from the linearized system models. The theoretical result was compared with the measured response index at the electric power plant, and the comparison result revealed the superior capability of the proposed mount module in controlling the reaction motion at the electric power plant.

Impact of blade mounting structures on cross-flow turbine performance

Cross-flow or vertical-axis turbines are flow energy conversion devices in which lift forces cause blades to rotate around an axis perpendicular to the flow. In marine currents, rivers, and some wind energy applications, cross-flow turbines are a promising alternative to more conventional axial-flow turbines. The performance implications of the choice of structure used to mount turbine blades to the central shaft are examined experimentally in a recirculating water flume. Turbine performance is found to be strongly dependent on the choice of the mounting structure. Power loss due to rotational drag on these structures is estimated experimentally by rotating the mounting structure without blades. Through a perturbation-theory approach, interactions between turbine blades and mounting structures are examined. Analytical models for the power loss due to mounting structure drag are introduced and shown to be consistent with experiments. To provide guidance for cross-flow turbine design, the models are re-formulated in terms of non-dimensional turbine geometric and operational parameters. Mounting blades solely at their mid-span is shown to decrease performance through multiple fluid effects. Using foil cross-section struts located at the turbine blade tips is found to result in the highest turbine performance.

An environmental Life Cycle Assessment of rooftop solar in Bangkok, Thailand

Abstract This study quantifies the environmental burdens created by a planned rooftop photovoltaic (PV) solar installation on a university campus in Bangkok, Thailand, and models the potential of rooftop solar to meet the country’s renewable energy goals. Impacts are evaluated using Life Cycle Assessment and recommendations made for upstream purchasing decisions according to different scenarios. Results indicate that main contribution to impacts occurs in manufacturing by stage and from PV modules by component. Impacts generated by the mounting structure and inverters are also significant, and together these components constitute over 90% of environmental burdens. A climate change impact of 0.079 kg CO2-eq/kWh is produced over the lifetime of the system. Energy Payback Time is calculated as 2.5 years, and the Economic Payback Period is 7.4 years. The system is estimated to avoid 1.00E+06 kg CO2-eq over its lifetime. Installation of similar rooftop PV systems on 50% of university and government buildings in Bangkok could result in a net reduction of 4.80E+09 kg CO2-eq. Domestic production of components and recycling of materials is identified as a best-case scenario, with alleviations across all impact categories. Economic analysis suggests on-site electricity consumption paired with a net-metering policy scheme is the best way to incentivize PV solar energy installations.

Dynamic modeling of vortex induced vibration wind turbines

Abstract This paper studies the dynamic modeling of four configurations of vortex-induced vibrations of a bladeless wind turbine (BWT). The BWTs consist of a bluff body mounted on a flexible structure in the flow field. The shape of the bluff body and its mounting structure are different among the proposed BWTs. The Euler-Bernoulli beam theory and the Galerkin procedure are used to derive a nonlinear distributed-parameter model for the BWTs under a fluctuating lift force due to periodically shedding vortices. The derived dynamic model is validated through comparison with a 3D CFD-FEM numerical simulation. The effects of the wind speed on the induced lift force, turbine deflection, and generated power of four BWTs are investigated. It is verified that the amplitude of the vibrations of the BWT increases significantly when the vortex shedding is synchronized with the structural oscillations. The results show that, while conic BWTs have a higher performance at post-synchronization region (i.e. high wind speeds), the right circular cylinder BWTs exhibits a better performance at pre-synchronization region (i.e. low wind speeds).

Prediction of Wind Velocity to Raise Vortex‐Induced Vibration through a Road‐Rail Bridge with Truss‐Shaped Girder

Vortex‐induced vibration (VIV) of bridges, related to fluid‐structure interaction and maintenance of bridge monitoring system, causes fatigue and serviceability problems due to aerodynamic instability at low wind velocity. Extensive studies on VIV have been performed by directly measuring the vortex shedding frequency and the wind velocity for indicating the largest girder displacement. However, previous studies have not investigated a prediction of wind velocity to raise VIV with a various natural frequency of the structure because most cases have been focused on the estimation of the wind velocity and peeling‐off frequency by the mounting structure at the fixed position. In this paper, the method for predicting wind velocity to raise VIV is suggested with various natural frequencies on a road‐rail bridge with truss‐shaped girder. For this purpose, 12 cases of dynamic wind tunnel test with different natural frequencies are performed by the resonance phenomenon. As a result, it is reasonable to predict wind velocity to raise VIV with maximum RMS displacement due to dynamic wind tunnel tests. Furthermore, it is found that the natural frequency can be used instead of the vortex shedding frequency in order to predict the wind velocity on the dynamic wind tunnel test. Finally, curve fitting is performed to predict the wind velocity of the actual bridge. The result is shown that predicting the wind velocity at which VIV occurs can be appropriately estimated at arbitrary natural frequencies of the dynamic wind tunnel test due to the feature of Strouhal number determined by the shape of the cross section.

비상 발전기용 마운트 모듈의 단순구조 설계

The heavy-weighted emergency electric generator is normally supported with several mount module in order to isolate the excitation of an combustion engine from the basement floor of a installed building or other environment. Current mount module is consisted of several machinery elements, spring, rubber and basement mass block, and the responsible supporting mounts pays much labors as well as installation time due to the sizable mass block. If it can be possible to simplify the mount structure under no basement mass block, the proposed supporting mount module can also reduce maintenance process considerably due to its simple structure. The feasibility of proposed mount module was theoretically evaluated with the response index, which is the ratio of response for two kinds of mount module, with and without basement mass block. In addition, the theoretical results were experimentally verified with the response of building floor under 100 % load of the electric generator.

Optimal design of a Φ760 mm lightweight SiC mirror and the flexural mount for a space telescope.

A flexural support technique for lightweighted Primary Mirror Assembly (PMA) of a space telescope is presented in this article. The proposed three-point flexural mount based on a cartwheel flexure can maintain the surface figure of the PMA in a horizontal optical testing layout. The on-orbit surface error of the PMA causes significant degradation in image quality. On-ground optical testing cannot determine the zero-gravity figure of the PMA due to surface distortion by gravity. We unveiled the crucial fact that through a delicate mounting structure design, the surface figure can remain constant precisely without inducing distinguishable astigmatism when PMA rotates with respect to the optical axis, and the figure can be considered as the zero-gravity surface figure on the orbit. A design case is described to show the lightweight design of a SiC mirror and the optimal flexural mounting. Topology optimization and integrated opto-mechanical analysis using the finite element method are utilized in the design process. The Primary Mirror and mounting structures were fabricated and assembled. After the PMA mirror surface was polished to λ/50 RMS, optical testing in different clocking configurations was performed, respectively, through rotating the PMA by multiple angles. Test results show that the surface figure remained invariant, indicating that gravity release on the orbit will not cause an additional surface error. Vibration tests including sweep sine and random vibration were also performed to validate the mechanical design. The requirements for the mounting technique in space were qualified.

Shading Effects of the Mounting Structure of Bifacial PV Modules and Impact to the Bypass Diode Lifetime

Shading Effects of the Mounting Structure of Bifacial PV Modules and Impact to the Bypass Diode Lifetime

Building integrated Photovoltaic Retrofitting in office buildings

The research main goal is to optimize the utilization of innovative renewable energy solutions focusing on the use of BIPV as an alternative to reduce dependency on fossil fuels and consequently reduce buildings carbon emissions.A feasibility analysis of a building scale photovoltaic system retrofitting is conducted for an office building. A series of PV system options will be assessed in terms of the costs and projected energy production of several PV systems through renewable energy simulations modeling software, PVSOL premium. Different types of PV module and different types of mounting structure will be selected for the feasibility analysis based on an analysis of the current PV industry standards. Each system's output capacity (kW) will be calculated, annual energy output (KWh) and initial project cost for these different systems will then be modeled in PVSOL premium.

Design Overview of DM Radio Pathfinder Experiment

We introduce DM Radio, a dual search for axion and hidden photon dark matter using a tunable superconducting lumped-element resonator. We discuss the prototype DM Radio Pathfinder experiment, which will probe hidden photons in the 500 peV (100 kHz)–50 neV (10 MHz) mass range. We detail the design of the various components: the LC resonant detector, the resonant frequency tuning procedure, the differential SQUID readout circuit, the shielding, and the cryogenic mounting structure. We present the current status of the pathfinder experiment and illustrate its potential science reach in the context of the larger experimental program.

Subjective absolute discomfort threshold due to idle vibration in passenger vehicles according to sitting posture

Idle vibration, occurring when a vehicle comes to a stop while the engine is on, is known to be a main cause of discomfort for passengers, and the customer effect has been recently growing. The frequency of idle vibration is determined by the engine type. To lower the vibration, various technologies have been applied to optimize the engine mount and vehicle body structure. In addition to the technological developments, research on human response with a consideration of idle vibration is needed to effectively reduce the level of discomfort experienced by passengers. Seats aimed at enhancing static comfort influence the sitting posture of passengers; sitting posture is a factor affecting human body characteristics that response to idle vibration. This study examined the absolute discomfort threshold of idle vibration according to the sitting postures of 13 taxi drivers. The four sitting postures of subjects on a rigid-body seat without a backrest were variables in the determination of absolute discomfort threshold of idle vibration. The absolute discomfort threshold curves obtained in this experiment were less sensitive to frequency changes than the frequency weighting function of ISO 2631-1.

鉄道車両の車体振動低減のための新たなヨーダンパ取付け構造の開発

It is pointed out that the yaw dampers, which are often installed in between carbody and bogie frame of a high-speed railway vehicle, have such unfavorable points that the damping force is generated not only in the yawing direction but also in other direction. As a result the damping force is generated also to the longitudinal or pitching vibration of a bogie, and the excitation force acts in the longitudinal direction of the carbody resulting in the increase of the carbody vibration of the longitudinal or vertical direction. In this research, to enable the reduction of the excitation of the carbody vibration while maintaining the original function of yaw dampers to prevent bogie hunting motion, a new mounting structure of yaw dampers on railway vehicles has been developed. The new mounting structure enables to reduce the excitation force transmitted from a bogie frame to a carbody through yaw dampers. In this paper, the effect of yaw dampers on the carbody vertical vibration is firstly shown based on the results of an excitation test of a full-scale vehicle, then the outline of the new mounting structure for yaw dampers and the design and manufacture of the prototype device are presented. The vehicle dynamics model based on multi body dynamics was constructed and the suppression effect of the yaw damper force generated to movement in the direction other than the yawing direction of a bogie was verified by the numerical simulation. Moreover, the prototype device was installed on a full-scale test vehicle and a bogie hunting motion test was carried out to verify the running stability.

Preload distribution on machine tool mounting structure by leveling work during installation

Preload distribution on machine tool mounting structure by leveling work during installation

Influence of yaw dampers on vertical vibration of railway vehicle carbody and verification of effect by the new mounting structure of yaw damper

Influence of yaw dampers on vertical vibration of railway vehicle carbody and verification of effect by the new mounting structure of yaw damper

Design, analysis, and testing of kinematic mount for astronomical observation instrument used in space camera.

A statically determinate kinematic mount structure is designed for an astronomical observation instrument. The basic principle of the proposed kinematic mount is introduced in detail, including the design principle, its structure, and its degrees of freedom. The compliance equations for the single-axis right circle flexure hinge are deduced, and mathematical models of the compliances of the bipod in the X-axis and Z-axis directions are established. Based on the index requirements, the range of one design parameter (the hinge groove depth, R) for the kinematic mount is determined. Parametric design is performed, with the entire structure being the design object and the first three eigenfrequencies as the design objective; the final design parameter for the kinematic mount is 1.9 mm. The first three eigenfrequencies of the final structure are 36.49 Hz, 38.65 Hz, and 72.41 Hz, which meet the frequency requirements. The Z-direction deformation and the bipod compliances in the X-axis and Z-axis directions are analyzed through simulations and experiments. The results show that (1) the Z-direction deformation of the bipod meets the displacement requirement; (2) the deviations between the finite element results and the compliance equation Cx results, and between the finite element results and the compliance equation Cz results are 8.8% and 3.92%, respectively; (3) the deviation between the experimental results and the compliance equation Cz results is 10.3%. It is concluded that the bipod compliance equations in the X-axis and Z-axis directions are valid, and that the kinematic mount thus meets the design requirements.

샌드위치 패널을 이용한 함정탑재장비용 방진 베이스 개발

The underwater radiated noise can be reduced by decreasing the structure borne noise of the on-board equipment. Therefore, the structure borne noise of the onborad installed equipment is strongly restricted by ROK navy with MIL-Std 740-2. Usually, the vibration transmissibility from the equipment to the hull of the ship is dependent on its mount characteristics. Even though the double mount structure is proper to apply for ship board application rather than single mount, it is not widely applied due to the weight and volume resriction of the ship. Therefore, in this research, the base using sandwitch panel which can act as double mount structure is suggested and its noise reduction capacity is verified with analytic calculation as well as experiment.