Tilt Adjustment Research Articles

Static measurement of absolute gravity in truck based on atomic gravimeter

Currently, most of the experimental apparatuses of atomic gravimeters are complex in structure, large in size, and poor in environmental adaptability, so that they cannot be used to implement the absolute gravity measurement. Thus, the application areas of atomic gravimeter are greatly limited. In this paper, we integrate a system of absolute gravity measurement on a truck based on a compact homemade atomic gravimeter. This atomic gravimeter has a small size, light weight, low power consumption, and its accuracy is estimated as 10 μGal in the case of laboratory environment. This system consists of atomic gravimeter for gravity measurement, passive isolation platform for vibration suppression, posture platform for tilt adjustment, differential GPS for altitude measurement, UPS for power supply, air-conditioned truck for temperature control and transportation. At first, we estimate the performance of environmental adaptability for this measurement system on the truck, and it is found that this system can still work even at a high field temperature of 40 ℃ and a big tilt angle of 8° for the road. Besides, the experimental procedures of absolute gravity measurement and the methods of processing measured data are introduced. The Coriolis effect is analyzed and the dependence of measured gravity on the orientation of the truck has been measured. Finally, the repeated line measurements are performed on a flat field road. The accuracy of self-coincidence for absolute gravity measurement is evaluated to be 30 μGal and the difference in measured gravity among different locations is about 3080 μGal. Besides, we obtain the vertical gravity gradient of the earth by measuring the absolute gravity values at different altitude sites on a slope road, and the value is estimated to be －231(36) μGal/m. The presented results can provide the basic reference for the field absolute gravity survey.

Probe misalignment calibration in fiber point-diffraction interferometer.

The measuring probe integrated with multiple fiber point-diffraction sources can be applied to measure both the three-dimensional coordinates and highly accurate point-diffraction wavefront. The probe determines the achievable measurement accuracy of fiber point-diffraction interferometer (PDI), in which the fiber exit end plane is required to be parallel with the detector plane. The probe misalignment due to fabrication error could introduce significant measurement error. A high-precision method is proposed to calibrate the probe misalignment in fiber PDI, including the central positioning based on phase difference and tilt adjustment based on Zernike polynomials fitting. Both numerical simulation and experiments have been carried out to demonstrate the feasibility and accuracy of the proposed probe misalignment calibration method. The proposed method provides a feasible way to address the processing uncertainty on measuring probe in fiber PDI, and enables high-precision geometry alignment and misalignment calibration in the interferometric testing systems with case of no imaging lens.

Projection Histogram-Assisted Estimation of Common Phase Error in Coherent Optical OFDM Systems

In this paper, we present a novel blind common phase error estimation method in coherent orthogonal frequency division multiplexing systems using projection histogram-assisted processing. In the proposed algorithm, the constellation of the signal distorted by common phase noise is regarded as a tilted image, which can be rotated back to the right position by tilt adjustment. Considering the characteristics of the constellation, the tilt adjustment can be realized under the assistance of projection histogram. By simply counting and maximizing the number of the projection points fell into certain intervals, the tile angle can be obtained, which means that the common phase error is known. Compared with the conventional blind phase searching method, the proposed method shows similar performance and reduced complexity. Moreover, we optimized the algorithm by dividing the estimation process into two stages, in which case the complexity can be further reduced without introducing bit error ratio penalty.

Development of an Autonomous Electric Robot Implement for Intra-Row Weeding in Vineyards

Intra-row weeding is a time consuming and challenging task. Therefore, a rotary weeder implement for an autonomous electrical robot was developed. It can be used to remove the weeds of the intra-row area of orchards and vineyards. The hydraulic motor of the conventional tool was replaced by an electric motor and some mechanical parts were refabricated to reduce the overall weight. The side shift, the height and the tilt adjustment were performed by linear electric motors. For detecting the trunk positions, two different methods were evaluated: A conventional electromechanical sensor (feeler) and a sonar sensor. The robot performed autonomous row following based on two dimensional laser scanner data. The robot prototype was evaluated at a forward speed of 0.16 ms−1 and a working depth of 40 mm. The overall performance of the two different trunk detection methods was tested and evaluated for quality and power consumption. The results indicated that an automated intra-row weeding robot could be an alternative solution to actual machinery. The overall performance of the sonar was better than the adjusted feeler in the performed tests. The combination of autonomous navigation and weeding could increase the weeding quality and decrease power consumption in future.

Modelling and simulation for installation feasibility of standalone photovoltaic system for Quetta, Pakistan

The impact and significance of renewable energy in developing countries is increasing rapidly in latest years. There is much need of energy dependence to be based on off grid photovoltaic systems in developing countries like Pakistan which are suffering from severe power shortfalls annually and load shedding concern. In this paper, a concept assessment and estimation of standalone photovoltaic system is done for the site of Quetta, Pakistan in comparison to the location of the Copiapo-Chamonate. Copiapo-Chamonate site is situated in Atacama Desert which is often labelled as the best solar irradiation receiving location in the world with maximum solar insolation reaching to 9.28 kWh/m2/day. The systems for both locations is modelled and simulated in PVSYST for a constant load of 11.9 kWh/day with seasonal tilt adjustment. According to the simulation, results of the parameters including performance ratio, solar fraction, energy supplied to the load etc. show that Quetta meet its individual household demand quite efficiently.

Adaptation of tilt adjustment and tracking force automation system on a laser-controlled land leveling machine

This study is about the mechanization and automation works carried out to improve the operational efficiency of the laser-controlled land leveling machines and to design a more precise, ergonomic, economical and reliable system. At first, the existing laser-controlled leveling shovel has been redesigned through a mechanical design thus being adapted to automation. The mechanical structure was driven by the hydraulic system and the hydraulic system was controlled by the PLC. This new design consists of blade tilt adjustment automation system, track automation system, and maximum load protection system. With its new design, the machine can level out harder lands by less number of repetitions and less fuel consumption with a gradient precision of 0.05°. After the design the time saving of 80% and the fuel saving of 85% has been achieved for the surfaces with the same area and approximately 10 L of fuel savings per acre has been performed. The new shovel system has been enabled to carry 1.3 times more soil for the same slope and also, just this modified machine can be used instead of using 3 separate land leveling machines for 3 different operations. Moreover, the requirement for land leveling in both directions has been avoided in leveling out narrow areas, especially on highway buildings.

Tilt adjustment to measuring instrument for piping inspection robot

Tilt adjustment to measuring instrument for piping inspection robot

Comparative analysis of seepage field characteristics in bucket foundation with and without compartments

By taking the importance of seepage parameters into account during the suction process, a comparison analysis of seepage field between bucket foundations with (C-BF) and without multiple subdivisions inside (N-BF) is performed in this paper, with the consideration of tilt adjustment as well as the complexity in underwater soil. Scaled model experiments were conducted at first to acquire the excess pore water pressure μe, and then the law of three-dimensional heat conduction was used to simulate the seepage field and the parameters of the two models. The results of simulations were compared with those of the model experiment, and it is shown that the computational results agree well with those of experiments; N-BF is more sensitive to the tilting of the bucket body than C-BF; the layered soil can protect the seepage filled with limited hydraulic gradient and seepage flux; basically the seepage field variations with the same internal structure under different working conditions have their own regularities.

OPTiM: Optical projection tomography integrated microscope using open-source hardware and software.

We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope’s existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations’ viability.

Performance of off-grid residential solar photovoltaic power systems using five solar tracking modes in Kunming, China

This paper compares the performance of a 2.02 kWp off-grid residential solar photovoltaic (PV) power system using PVSYST simulation software for a household in Kunming, Yunnan province, China. The monthly available solar energy; missing energy; array, final, and reference yields, performance ratio; and array capture and system losses were analyzed for five solar tracking modes: fixed tilted plane, seasonal tilt adjustment, horizontal axis tracking, vertical axis tracking, and dual axis tracking. Although there were some similar aspects across the five systems, minimum available solar energy (2461 kWh/y) and maximum missing energy (134.68 kWh/y) were obtained using the fixed tilted plane system (tilt angle = 25°, azimuth angle = 0°), whereas maximum available solar energy (3081 kWh/y) and minimum missing energy (48.53 kWh/y) in October were obtained using the dual axis tracking system. Average monthly performance ratio was maximal for the fixed tilted plane system (0.689), and minimal for the dual axis tracking system (0.596).

Guideline-recommended 15° left lateral table tilt during cesarean section in regional anesthesia—practical aspects: An observational study

ObjectiveLeft lateral table tilt of 15° to 30° is recommended for cesarean section, although little is known about the practical problems of its implementation. This study examines these issues from the perspective of anesthesiologists, obstetricians, theater nurses, and patients. Initially, the tilt was set by visual estimation in 100 women and checked by inclinometer afterwards. Study DesignObservational survey. PatientsOne hundred women undergoing primary cesarean section. InterventionThe anesthesiologist's initial estimated tilt setting was documented, then patient comfort and obstetrician's needs were assessed at 15°, and the tilt was adjusted accordingly. Problems were identified, and possible solutions were introduced. The effects of our solutions were reevaluated after 12months. ResultsDespite appropriate training, too little tilt was achieved in most cases. Even with objective inclinometry, complaints by patients, obstetricians, and theater nurses made physicians reluctant to press for 15° tilt. Better compliance was achieved by the introduction of a 2-step tilt procedure, side bar mounting, and inclinometry. After 12months, 96% of anesthesiologists were using the inclinometer to set at least 10°. Most observed an improvement in patient care. ConclusionImplementation of 10° to 15° tilt requires objective inclinometry. It allows tilt adjustment to be made by interdisciplinary staff in greater confidence that patient comfort and surgical conditions will not be impaired. Strategies to reduce discomfort are presented in this article.

The two dimensional fold test in paleomagnetism using ipython notebook

One aspect of paleomagnetic analysis prone to controversy is the result of the fold test used to evaluate the age of a magnetisation component relative to the age of a structural event. Initially, the fold test was conducted by comparing the Fisherian precision parameter (k) to results from different limbs of a fold structure before and after tilt adjustment. To accommodate synfolding magnetisation, the tilt correction can be performed in stepwise fashion to both limbs simultaneously, here called one dimensional (1D) fold test. The two dimensional (2D) fold test described in this paper is carried out by applying stepwise tilt adjustment to each limb of the fold separately. The rationale for this is that tilts observed on contrasting limbs of deformed structure may not be synchronous or even belong to the same episode of deformation. A program for the procedure is presented here which generates two dimensional values of the k-parameter visually presented in contoured form. The use of ipython notebook enables this 2D fold test to be performed interactively and yield a more precise evaluation than the primitive 1D fold test.

Intelligent Scanning Electrochemical Microscopy Tip and Substrate Control Utilizing Fuzzy Logic

In this paper, we present a technique to intelligently control the motion of Scanning Electrochemical Microscopy (SECM) tip electrodes and automatically align SECM tip electrodes to the substrate with no user interaction. This intelligent method utilizes a custom fuzzy logic algorithm to control the motion of the tip electrode and automate tip/substrate alignment. The fuzzy logic control algorithm rapidly obtains SECM approach curves via a variable speed approach and automatically stops the tip electrode at a preprogrammed tip/substrate distance without “crashing” the tip electrode into the substrate. The fuzzy logic algorithm automatically adjusts the speed of the electrode based on the tip size, the enhancement of the tip current, and the distance that the tip electrode is from a user defined setpoint. We validated that both positive feedback and negative feedback approach curves obtained using the fuzzy logic algorithm matched well with simulated approach curves for both large microelectrodes (sometimes used for Surface-Interrogation SECM, a=175μm) and for conventional SECM ultramicroelectrodes (a=4.2μm). The ability to automatically stop the tip electrode is crucial for the automated sample tilt adjustment protocol. This ability allows us to automate the interactive process of (1) approaching the tip to the substrate, (2) scanning the tip across the substrate to measure the tip/substrate tilt, (3) correcting for the tip/substrate tilt. We demonstrated that this tip/substrate alignment protocol allows us to obtain highly resolved constant-height SECM images over large areas with ease.

Polyhedron tracking and gravity tractor asteroid deflection

In the wake of the Chelyabinsk airburst, the defense against hazardous asteroids is becoming a topic of high interest. This work improves the gravity tractor asteroid deflection approach by tracking realistic small body shapes with tilted ion engines. An algorithm for polyhedron tracking was evaluated in a fictitious impact scenario. The simulations suggest a capability increase up to 38.2% with such improved tilting strategies. The long- and short-term effects within polyhedron tracking are illustrated. In particular, the orbital reorientation effect is influential when realistic asteroid shapes and rotations are accounted for. Also analyzed is the subject of altitude profiles, a way to tailor the gravity tractor performance, and to achieve a steering ability within the B-plane. A novel analytical solution for the classic gravity tractor is derived. It removes the simulation need for classic tractor designs to obtain comparable two body model Δv figures. This paper corroborates that the asteroid shape can be exploited for maximum performance. Even a single engine tilt adjustment at the beginning of deflection operations yields more deflection than a fixed preset tilt.

Assessment of solar and wind energy potentials for three free economic and industrial zones of Iran

This paper aims to evaluate the potential of renewable energy sources of solar and wind in three free economic and industrial zones of Chabahar, Kish and Salafchegan in Iran. Feasibility of harnessing solar energy was investigated by using key solar parameters like monthly mean global, beam and diffuse solar radiation as well as clearness index. It was found that all locations had great potentials for utilizing different solar energy systems. Additionally, the monthly, seasonal, semi-yearly and yearly optimum tilt angles of south-facing solar surfaces were determined. For all zones, adjusting the tilt angle twice a year or in other words, the semi-yearly tilt adjustment for two periods of warm (April–September) and cold (October–March) were highly recommended, since it offers almost the same level of annual solar energy gain (SEG) as those of monthly and seasonal adjustments. Weibull Distribution Function (WDF) was performed for analyzing the wind potentials at different heights. It was found that Chabahar was not suitable for wind energy development, but Kish and Salafchegan with yearly wind powers of 111.28W/m2 and 114.34W/m2, respectively ranked in class 2 which are considered marginal for wind power development. Three different wind turbine models were proposed for Kish and Salafchegan.

Establishing a diffuse solar radiation model for determining the optimum tilt angle of solar surfaces in Tabass, Iran

In this study the optimum tilt angle for south-facing solar surfaces in Tabass, Iran, for the fixed monthly, seasonal, semi-yearly and yearly adjustments were calculated. Due to lack of measured diffuse solar radiation data, to predict the horizontal diffuse radiation nine diffuse models from three different categories were established. Based on some statistical indicators the three degree model, in which both clearness index and relative sunshine duration are variables, was recognized the best. The monthly optimum tilt varies from 0° in June and July up to 64° in December and the yearly optimum tilt is around 32°, which is very close to latitude of Tabass (33.36°). For different adjustments, particularly for a vertically mounted surface, the received monthly mean daily solar radiation components and the annual solar energy gains were calculated and compared. Total yearly extra solar gain for the monthly, seasonal, semi-yearly and yearly optimally adjusted surfaces compared to that of horizontal surface are 23.15%, 21.55%, 21.23% and 13.76%, respectively. The semi-yearly tilt adjustment of 10° for warm period (April–September) and 55° for cold period (October–March) is highly recommended, since it provides almost the same level of annual solar energy gain as those of monthly and seasonal adjustments.

Model tests on tilt adjustment techniques for a mooring dolphin platform with three suction caisson foundations in clay

A series of installation model tests have been performed in order to investigate the influence of the inclination angle on caisson installation penetration behavior during the suction-assisted penetration process and to explore the feasibility of the caisson tilt adjusting technique by applying suction/positive pressure and intermittent pumping among the caissons. The specially designed experimental model was a mooring dolphin platform with three suction caisson foundations. The test results indicate that the tilt angle could be adjusted to 0.5° by applying different suction pressures inside the caissons in soft clay during the suction-assisted penetration process, even with an initial tilt angle of up to 6.28°. Moreover, in stiff clay, it was still possible to adjust the tilt from 6.6° to 1.29°. Aside from applying the suction in the caissons, positive pressures were also applied to the caissons during the tilt adjustment at larger tilt angles. The reciprocating tilt adjustment process resulted in a larger soil heave, especially at larger tilt angles. This side effect would make the final insertion depth of the suction caisson less than the designed depth.

Distinct mechanisms control contrast adaptation over different timescales

Changes to the visual environment can happen at many timescales, from very transient to semi-permanent. To adapt optimally, the visual system also adjusts at different timescales, with longer-lasting environmental changes producing longer-lasting effects, but how the visual system adapts in this way remains unknown. Here, we show that contrast adaptation-the most-studied form of visual adaptation-has multiple controllers, each operating over a different time scale. In a series of experiments, subjects completed either a contrast matching, contrast detection, or tilt adjustment task, while adapting to contrast at one orientation. Following a relatively longer period (5 min) of adaptation to high contrast, subjects were "deadapted" for a shorter period (e.g., 40 s) to a lower contrast. Deadaptation eliminated perceptual aftereffects of adaptation, but continued testing in a neutral environment revealed their striking recovery. These results suggest the following account: Adaptation was controlled by at least two mechanisms, with initial adaptation affecting a longer-term one and deadaptation affecting a shorter-term one in the opposite direction. Immediately following deadaptation, the effects of the two mechanisms cancelled each other, but the short-term effects rapidly decayed, revealing ongoing longer-term adaptation. A single controlling mechanism cannot account for the observed recovery of effects, since once deadaptation cancels the initial longer-term adaptation, no trace of it remains. Combined with previous results at very long adaptation durations, the present results suggest that contrast adaptation is possibly controlled by a continuum of mechanisms acting over a large range of timescales.

Cost effective design of compound parabolic collector for steam generation

In this paper we present a working model of Compound Parabolic Collector (CPC) system for the application of process steam generation. It is easy for fabrication, operation and has a lower cost compared to other available concentrating solar collector systems with further possibility of lowering the cost. An experimental demonstration unit having an aperture area of nearly 30m2 was set up and tested for steam generation. The performance analysis of the system shows potential of improving thermal efficiency up to 71%. By virtue of its geometry, the proposed CPC system requires much lesser mirror area compared to conventional CPC design and require single tilt adjustment per day for a daily 6h operation.

Beam-based alignment of injection bump magnets using remote-controlled tilt adjustment system at SPring-8

The top-up operation mode is becoming the standard operation mode in most facilities of third-generation light sources. In the top-up operation mode, it is important to keep the stored beam stable during beam injection in order for synchrotron radiation users to continue their experiments without disturbance. The injection bump magnets, however, have some alignment error in their rotation around the beam axis (tilt error), and this causes oscillation of the stored beam in the vertical direction. To suppress this oscillation, we developed a beam-based method of aligning the bump magnets using a remote-controlled tilt adjustment system. Applying the method, we could reduce the amplitude of the vertical oscillation to 0.4μm, which is approximately 1/40 of the r.m.s. beam size in the vertical direction.