Tilt Angle Measurements Research Articles

Design of Tilt Angle Measurement System

For the purpose of inclination measurement and monitoring, a tilt angle measurement system using a heat convection accelerometer is presented in this study. A conditioning circuit that center around the single chip processor is designed and built. Experiments were carried out to characterize the measuring system with the range of-90° to +90°. The output results show nonlinear relationship. The calibration result indicates that the sensitivity of the accelerometer is about 650mV/g. The maximum error is 5.5% while the repeatability error is 3%. Experiments proved that the developed measurement system is capable of measuring tilt angle.

Reliability and validity of goniometric and photographic measurements of clavicular tilt angle

The aims of the present study were to assess the reliability of clavicular tilt angle measurement using goniometric and photographic measurements and to test the validity of the measurement by comparing the results with radiographic findings (gold standard).Clavicular tilt angles were measured in 18 healthy subjects (36 clavicles) using goniometric, photographic, and radiographic measurement. Repeated measurements using goniometric and photographic measurements were made in two test sessions conducted on different days by two examiners to assess inter-rater and intra-rater reliability of the two methods. Radiographic measurement was taken once, and the correlation between the radiographic findings and those of the indirect methods was calculated to test the validity of the goniometric and photographic measurement of clavicular tilt angle.No significant difference in clavicular tilt angle measurement was found between test sessions. The reliability of goniometric measurement (inter-rater intraclass correlation coefficients (ICC) = 0.85 (95% CI = 0.72–0.92) − 0.87 (95% CI = 0.77–0.87); intra-rater ICC = 0.80 (95% CI = 0.64–0.89)) and photographic measurement (inter-rater ICC = 0.89 (95% CI = 0.80–0.94) − 0.95 (95% CI = 0.91–0.98); intra-rater ICC = 0.84 (95% CI = 0.71–0.92) − 0.84 (95% CI = 0.69–0.91)) were excellent. The goniometric and photographic measurements of clavicular tilt angle were highly correlated with the radiographic findings (r = 0.83, 0.78, respectively). Goniometric and photographic measurements of clavicular tilt angle obtained by raters in this study may be considered reliable, and data obtained using the goniometric and photographic measurements are representative of radiographic findings of clavicular tilt angle.

Research on Sag Online Monitoring System for Power Transmission Wire Based on Tilt Measurement

Sag online monitoring system for power transmission wire based on tilt angle measurement was proposed, the mathematical model of catenary for power wire was established. Sag calculation models of power wire in the situation without swinging and swinging were derived. By measuring the power wire axial angle and swing angle with dual-axis tilt sensor, the sag could be accurately calculated with the wire swinging. By testing the sag detection system, the result showed that the sag detection system could meet the engineering requirements of sag measurement.

Conformational Stability and Substrate Translocation - A Computational Study of the Leucine Transporter

The human monoamine transporters are involved in a variety of disorders and thus important medicinal targets.1 There are no available high-resolution structures of the transporters. The leucine transporter (LeuT) is a bacterial homolog of the human monoamine transporters with a sequence similarity of 20-24 %.2 LeuT has been crystallized with a number of different ligands and in several different conformations. Most recently, an inward facing conformation was solved.3 The crystallization process required the use of four point mutations as well as the association of an antibody. We have applied computational methods to investigate whether the conformation of this manipulated protein is relevant for the wild-type transporter in a membrane environment. We have performed several molecular dynamics simulations of both the mutated and wild-type transporter, and analyzed the stability through measurements of helix tilt angles. The simulations reveal that the mutant and wild-type systems types behave similarly and both maintain a relatively stable inward facing conformation. The crystal structure of LeuT in an inward facing conformation does not contain any ligands or ions. To investigate the release of substrate and ions from the transporter, we have also performed simulations of wild-type LeuT in the inward facing conformation with sodium and either leucine or alanine bound. From this, we can conclude that one of the two sodium binding sites is fully disrupted in this conformation leading to the release of this ion in almost all of the simulations. Furthermore, in one of the simulations we observe release of alanine along with the second sodium ion, and are thus able to describe the translocation process in atomic detail.1. Br J Pharmacol (2012) 167, 256-278.2. Mol Pharmacol (2006) 70, 1630-1642.3. Nature (2012) 481, 469-474

Measurement of multi-directional azimuth and tilt angles using an improved DVD pickup head with a CMOS sensor: A simulation design study

We present a new detection method for an improved DVD pickup head system capable of measuring the multidirectional azimuth and small tilt angles. A complementary metal-oxide semiconductor (CMOS) sensor is used to capture images and analyze the slight shift of the central position of the beam shape when the test plane rotates to create a tilt angle and angular signal. The proposed detection method can determine the azimuth angle of the test plane from 0° to 360° at intervals of 5°. The tilt angle measurement is varied from 0° to 4.2° at intervals of 0.3°. The simulation results show that the improved DVD pickup head system can recognize multi-directional azimuth angles of the test plane under a small tilt.

Study of optical shuttering action in supramolecular hydrogen bonded nematogens

Supramolecular hydrogen bonded mesogens are formed between p-n-undecyloxy benzoic acid (11BAO) and p-n-alkyl benzoic acids (nBA, where n = 2–8). The isolated mesogens are characterized by distinct techniques in order to appreciate the optical, thermal, electrical, and dielectric properties. The optical tilt angle measurement is studied for all the members of this homologous series and is found to concur with the mean field theory predicted value. An interesting factor to notice is the observation of optical shuttering action in nematic phase of the entire series which privilege these materials to be used as light modulators. Dielectric measurements were carried out and the dispersion curves were discussed in terms of relaxation frequency and activation energies.

A Physical Approach To Specifically Improve the Mobility of Alkane Liquid Drops

Seamless control of resistance to liquid drop movement for polar (water) and nonpolar alkane (n-hexadecane, n-dodecane, and n-decane) probe liquids on substrate surfaces was successfully demonstrated using molten linear poly(dimethylsiloxane) (PDMS) brush films with a range of different molecular weights (MWs). The ease of movement of liquid drops critically depended on polymer chain mobility as it relates to both polymer MW and solvent swelling on these chemically- and topographically identical surfaces. Our brush films therefore displayed lower resistances to liquid drop movement with decreasing polymer MW and surface tension of probe liquid as measured by contact angle (CA) hysteresis and tilt angle measurements. Subsequently, while mobility of water drops was inferior and became worse at higher MWs, n-decane drops were found to experience little resistance to movement on these polymer brush films. Calculating CA hysteresis as Δθ(cos) = cos θ(R) - cos θ(A) (θ(A) and θ(R) are the advancing and receding CAs, respectively) rather than the standard Δθ = θ(A) - θ(R) was found to be advantageous for estimation of the actual dynamic dewetting behavior of various probe liquids on an inclined substrate.

P‐137: Measurement of the LC Pretilt Angle and Polar Anchoring in Cells with Homogeneous and Inhomogeneous LC Director Configuration and Weak Anchoring on Organosilicon Aligning Films

AbstractNew optical and electro‐optical methods of LC director average tilt angle measurement are described in LC cells with homogeneous and inhomogeneous LC director distribution. The LC pretilt on both LC substrates can have the same or opposite direction. Both LC pretilt angle and polar anchoring energy values have been measured for both polar and weak polar liquid crystal materials on aligning films of organosilicon compounds (OC) of different molecular structure. The method developed can be used also in optical compensator design.

Tilt-angle measurement of a sample stage using a capacitive liquid-based inclinometer

Alignment of projection images in tomographic reconstruction is a critical process that governs the quality of the reconstructed three-dimensional (3D) image. The most popular alignment method is the marker-based alignment, which typically uses colloidal gold particles added to the specimen (called fiducial markers) to calculate the coordinates of each projection image in the tilt series. This method, however, is not effective when each image contains only a small number of fiducial markers. Therefore, of all the parameters required for alignment, we focussed on the tilt angle and attempted to gage it directly in order to examine whether the acquired angle is accurate enough to perform tomographic reconstruction. We showed that the tilt angle measured using a commercially available capacitive liquid-based inclinometer is more precise than the reading from the monitor of the electron microscope and that it can lead to 3D reconstructions of quality similar to those obtained by the marker-based alignment method.

Study of change in dispersion and orientation of clay platelets in a polymer nanocomposite during tensile test by variostage small-angle X-ray scattering

To understand the change in dispersion and orientation of clay platelets in three-dimensional space during tensile test, neat polymer and its nanocomposite samples were studied by small- and wide-angle X-ray scattering (SWAXS). The samples after tensile tests were examined by tilting and rotating them with respect to the incident X-ray beam and also by scanning them at different positions. The tilt angle measurements provide better understanding on the dispersion and orientation of the clay platelets in nanocomposite. On the other hand, rotation and scanning measurements reveal details information on the orientation of polymer crystal planes due to the tensile stretching and percent crystallinity. Finally, the focussed ion beam electron tomography was employed to support the dispersion and orientation models of clay platelets proposed on the basis of SWAXS analyses.

Binary mixtures of liquid crystalline compounds with a reentrant smectic-A*phase

Binary mixtures of chiral liquid crystalline homologs have been studied. One compound designated 9ZBL exhibited reentrancy of a paraelectric smectic-A* phase, SmA*(RE), below the ferroelectric SmC* phase in the SmA*-SmC*-SmA*RE phase sequence. Stabilization of the SmA(RE) phase is established from studying binary mixtures of 9ZBL with its neighboring homologs 8ZBL and 10ZBL. Compound 8ZBL exhibits only SmA* phase in a wide temperature range and for 10ZBL the SmA*-SmC* phase sequence is observed on cooling. X-ray studies, dielectric spectroscopy, polarization, and tilt angle measurements have been carried out to characterize studied materials. For binary mixtures 9ZBL-10ZBL the reentrant SmA_(RE*) phase is observed for all studied concentrations. For binary mixtures 9ZBL-8ZBL a very small amount of 8ZBL (up to 0.5 mole %) causes disappearance of the SmC* phase. Nevertheless, a small anomaly in the temperature dependencies of the layer spacing, d(T), accompanied by a significant decrease in diffracted x-ray intensity occurs within the SmA* phase for mixtures containing up to 20 mole % of 8ZBL. This anomaly is evidence of the existence of a boundary between the SmA* and SmA(RE*) phases, thus proving their different nature.

Design and characterization of hydrogen bonded ferroelectric liquid crystals: A study of light modulation in nematic and smectic orderings

A novel series of hydrogen bonded ferroelectric liquid crystals (HBFLC) have been isolated. Phase transition temperatures obtained by differential scanning calorimetry (DSC) and textural observations elicited by polarizing optical microscope (POM) studies are discussed. Phase diagram is constructed from the above data. Salient feature of the present work is observation of a light modulation due to field induced transitions (FiT) in nematic and smectic C* phases. Tilt angle measurements in various FiT of smectic C* phase are discussed. One of the mesogens in nematic phase behaves like an optical modulator; helical pitch measurements support the above observation.

Design and Simulation of Electromagnetic Two-Dimensional MOEMS Scanning Mirror

This paper presents design methodology, dynamics simulation and fabrication process of a magnetically actuated two-dimensional MOEMS scanning mirror with piezoresistor sensors. In the device, the mirror has two gimbal structures with two integrated driving coils and piezoresistors for the control and measurement of the both tilt angles, respectively. The dynamic model is established and the FEM simulation results show that the resonant frequencies for both directions are 254Hz and 523Hz, respectively. The two-dimensional MOEMS scanning mirror has advantages of tilt angles control and measurement feedback for the both directions.

Intensity-modulated optical fiber sensors based on chirped-fiber Bragg gratings

Intensity-modulated fiber Bragg grating (FBG) sensors, compared with normal wavelength-encoding FBG sensors, can reduce the cost of sensor system significantly by using cost-efficient optical power detection devices, instead of expensive wavelength measurement instruments. Chirped-FBG (CFBG) based intensity-modulated sensors show potential applications in various sensing areas due to their many advantages, including inherent independence of temperature, high measurement speed, and low cost, in addition to the merits of all fiber-optic sensors. This paper theoretically studies the sensing principle of CFBG-based intensity-modulated sensors and briefly reviews their recent progress in measurement of displacement, acceleration, and tilt angle.

Imaging measurement and analysis of normal tilt angle of atrium septum

The atrium septum is tilted in heart. There is an angle between atrium septum and the cross section of body, which is called tilt angles of atrium septum (TAAS) in this study, however this angle has not been specifically mentioned in literatures. In this article TAAS was measured and analysed on axial images of contrast enhanced magnetic resonance (CEMR) of normal heart in order to understand quantitatively and accurately the anatomical structure of heart and to supply anatomical basic for some relevant operation. In this article 180 cases of axial images of CEMR of healthy hearts without any organic or functional heart disease were adopted, TAAS were measured and analysed statistically. On axial images of CEMR of healthy hearts the normal range of TAAS is from 12.43° to 55.60°, the average ± SD is 34.36 ± 6.92°, they are independent of sex and age as well as the position of heart, the distribution is relatively concentrated, the individual difference is rather small.

Application of wavelet filtering techniques to Lau interferometric fringe analysis for measurement of small tilt angles

This communication presents the results of investigation undertaken towards testing the viability of wavelet filtering techniques in analyzing the Lau interferometric fringes. Towards this, the applicability of Haar, Daubechies and Symlet wavelet based filtering schemes have been tested. Of these schemes, the Symlet based filtering scheme gives the best results in terms of improved signal to noise ratio. This scheme is then used to analyze Lau interferograms recorded in the experimental arrangement for tilt angle measurement. The processed interferograms yield improved accuracy and precision of measurement.

Advanced diagnostics of position sensors for the actuation systems of high-speed tilting trains

Trains tilting permits a train to travel at a high speed while maintaining an acceptable passenger ride quality with respect to the lateral acceleration, and the consequent lateral force, received by the passengers when the train travels on a curved track at a speed in excess of the balance speed built into the curve geometry. The tilting of a train carbody is performed by a control and actuation system which operates as a closed servoloop accepting the commands from the train control system, generating the torque necessary to tilt the carbody with respect to the bogie and measuring the tilt angle to close the control loop. Measurement of the tilt angle of each train vehicle is performed by two sensors located in the front and rear part of the vehicle. Since a correct tilt angle measurement is vital for the system operation and for ensuring a safe ride, in case of discrepancy between the signals of the two tilt angle sensors of any vehicle, the tilting operation is disabled and the train speed is reduced. An innovative tilt angle sensors health management system is herein presented that makes intelligent use of all available information to allow detection of malfunctioning of an individual tilt angle sensor, thereby enabling a continued operation of the tilting system and a high speed travel after a sensor failure occurs.

Vascularised fibular graft for the treatment of congenital pseudarthrosis of the tibia: long-term complications in the donor leg

Treatment of congenital pseudarthrosis of the tibia is still controversial, and vascularised fibula graft is a reliable method for consolidation, although complications can occur in the donor leg after fibula grafting. This study evaluates 16 patients with congenital pseudarthrosis of the tibia (CPT) treated with contralateral fibular graft, with regard to complications in the donor leg, and assesses the influence of distal tibiofibular joint arthrodesis in these complications. All patients with CPT were consecutively submitted to surgical treatment with contralateral fibular graft. The mean follow-up was 94 months, varying from 44 to 162 months. The long-term effects in the donor leg were determined, and 12 cases with distal tibiofibular arthrodesis (group 1) were compared with a group without arthrodesis (group 2). Half of the patients had proximal migration of the lateral malleolus. Eight patients had ankle valgus. Group 1 had an average valgus tilt angle of 5.8°, while group 2 had an average angle of 1.5°. There was no significant difference between the patients with or without distal tibiofibular joint arthrodesis. The patients with a distal fibula remnant smaller than 5 cm had greater valgus tilt angle measurements. Distal tibiofibular arthrodesis was not effective in preventing all the complications in the donor leg; however, it can lessen the severity of the complications. Our results show that a distal fibular remnant greater than 5 cm should be retained to prevent ankle valgus.

Sunspot group tilt angles and the strength of the solar cycle

It is known that the tilt angles of active regions increase with their latitude (Joy's law). It has never been checked before, however, whether the average tilt angles change from one cycle to another. Flux transport models show the importance of tilt angles for the reversal and build up of magnetic flux at the poles which is, in turn, correlated with the strength of the next cycle. Here we analyse time series of tilt angle measurements and look for a possible relationship of the tilt angles with other solar cycle parameters, in order to glean information on the solar dynamo and to estimate their potential for predictions of solar activity. We employ tilt angle data from Mount Wilson and Kodaikanal observatories covering solar cycles 15 to 21. We analyse the latitudinal distribution of the tilt angles (Joy's law), their variation from cycle to cycle and their relationship to other solar cycle parameters, such as the strength, amplitude and length. The two main results are: 1. An anti-correlation between the mean normalized tilt angle of a given cycle and the strength (or amplitude) of that cycle, with a correlation coefficient of r=-0.95 and r=-0.93 for Mount Wilson and Kodaikanal data, respectively. 2. The product of the cycle averaged tilt angle and the strength of the same cycle displays a significant correlation with the strength of the next cycle (r=0.65 and r=0.70 for Mount Wilson and Kodaikanal data, respectively). An even better correlation is obtained between the source term of the poloidal flux in Babcock-Leighton-type dynamos (which contains the tilt angle) and the amplitude of the next cycle. The results of this study indicate that in combination with the cycle strength, the active region tilt angles play an important role in building up the polar fields at cycle minimum.

Temperature-Insensitive 2-D Pendulum Clinometer Using Two Fiber Bragg Gratings

A novel two-dimensional (2-D) clinometer has been demonstrated by attaching two fiber Bragg gratings (FBGs) on a deliberately designed pendulum composed of a tapered cylindrical beam and a mass. Due to the nonuniform tilt-induced strain field applied along the length of the FBGs, the bandwidths of their reflection spectra vary linearly with the applied inclination. By monitoring the reflected optical powers of the two FBGs, temperature-independent measurement of 2-D tilt angle is realized. In the experiment, a high sensitivity of 1.96 μW/degree over the inclination range from - 4° to 4° is achieved, and the accuracy for tilt angle measurement is ±0.125°.