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Tibiofemoral synchronization technique matches the rotational alignment of the tibial component to the femoral component during the total knee arthroplasty (TKA). The rotational axis of the proximal tibia can be changed by this technique, which affects tibial torsion postoperatively. The purpose of this study was to investigate whether the tibiofemoral synchronization technique affect the tibial torsion, and the lower limb rotation after primary TKA. It was hypothesised that the tibial torsion would change after primary TKA. Ninety-three posterior stabilised TKAs from 89 patients were included from January 2017 to December 2018. Mechanical hip–knee–ankle axis (mHKA), in plain radiographs, femoral anteversion, tibial torsion, femoral neck-malleolar angle (FNMA), and rotational alignment of the femoral and the tibial components in pre- and postoperative CT scans were measured by two blinded observers. The primary outcome was a postoperative change in femoral anteversion, tibial torsion and FNMA. Clinical outcomes were evaluated using the American Knee Society Knee Score (AKSKS)/Function Score (AKSFS), and Oxford Knee Score (OKS) preoperatively and at 1 year after TKA. Patients’ perception of changes in the foot progression angle after TKA was investigated. Statistical significance was set at p

We aimed to evaluate whether there is a consensus among bi- (2D) and three-dimensional (3D) evaluations of mandible condyle position and its rotation center. Also, if this data can be replicated in orthognathic surgery planning. The survey was carried out on the major databases (PubMed, SCOPUS, Embase, Cochrane). Human or human bio models evaluations in 2D or 3D of mandibular condylar position concerning its fossa and rotational axis for orthognathic surgery planning were eligible. The heterogeneity of the studies and uncertainties in methodological biases did not allow us to identify the superiority of 2D or 3D methodology in determination of the condylar rotational axis. There is a lot of divergences in the definition of occlusal relationships among dental specialties. Although there was no consensus regarding condylar position in relation to the fossa, the most reported axis of rotation was positioned posterior-inferior. Weak scientific evidence and divergences in dental vocabulary shows the need for clinical studies with more accurate and transparent methodological design to standardize concepts. Despite we cannot affirm, we can suggest that the centric relation (CR) is not the condylar position when clinically manipulated in the posterior superior direction. This condylar position is the retruded contact position (RCt) while CR is the functional position of the condyle. In this way, the orthognathic surgery has two occlusal relationships during planning and execution. The ideal axis of rotation for orthognathic surgery planning must be fixed, permit individualization for each condyle and be reproducible. The 2D planning is obsolete as cannot provide all the necessary tools for an accurate planning.

In the field of modern manufacturing, probes have been playing a more and more crucial role. However, contact probes are unfit for measuring objects with soft surfaces or very tiny cavities and require radius compensation of stylus. In comparison, noncontact probes such as optical probes do not have to consider these problems and are well-performed in measurement. However, existing optical probes (triangulation) may fail to detect objects with rich spatial structures (due to the occlusion effect) and highly reflective curved surfaces (due to existence of highlight spots). Considering the problems, an optical probe based on discrete rotational symmetric triangulation is proposed in this paper. The emitting laser beam of the probe is the rotational axis and the five receiving optical paths (lenses and mirrors) are rotationally symmetrically distributed around the laser axis and are coimaged on a CMOS camera. Results of simulations and experiments show that the new-established prototype is designed with good robustness under various conditions such as different surface characteristics and different inclination degrees. The probe enables conducting real-time on-machine measurement without directional dependency with a resolution of 39 μm and repeatability accuracy of 0.72 μm.

In this paper, we present a method that uses a combination of experimental and modeled data to assess properties of x‐ray beam measured using a small‐animal spectral scanner. The spatial properties of the beam profile are characterized by beam profile shape, the angular offset along the rotational axis, and the photon count difference between experimental and modeled data at the central beam axis. Temporal stability of the beam profile is assessed by measuring intra‐ and interscan count variations. The beam profile assessment method was evaluated on several spectral CT scanners equipped with Medipix3RX‐based detectors. On a well‐calibrated spectral CT scanner, we measured an integral count error of 0.5%, intrascan count variation of 0.1%, and an interscan count variation of less than 1%. The angular offset of the beam center ranged from 0.8° to 1.6° for the studied spectral CT scanners. We also demonstrate the capability of this method to identify poor performance of the system through analyzing the deviation of the experimental beam profile from the model. This technique can, therefore, aid in monitoring the system performance to obtain a robust spectral CT; providing the reliable quantitative images. Furthermore, the accurate offset parameters of a spectral scanner provided by this method allow us to incorporate a more realistic form of the photon distribution in the polychromatic‐based image reconstruction models. Both improvements of the reliability of the system and accuracy of the volume reconstruction result in a better discrimination and quantification of the imaged materials.

PURPOSE The aim of this cross-sectional study was to assess maximum restraining lip force (MLF), maximum voluntary bite force (MBF), and patient-related parameters to evaluate their influence on masticatory function in four groups of participants with different dental states. METHODS Participants were recruited and assigned to one of four different groups depending on dental status: complete removable dental prostheses (CRDP group); edentulous with two-implant overdentures (IOD group); Kennedy Class I partial removable dental prostheses (PRDP group); or fully dentate (control group). A dental examination was performed and history taken. MLF was measured as the maximum withstood pulling force with three sizes of oral screens, MBF was evaluated using a digital force gauge, and masticatory performance was assessed using a two-color mixing ability test. Linear regression was used to determine the predictive effects of covariates on masticatory performance. Global and pairwise comparisons were also carried out. RESULTS A total of 68 participants with an average age of 69.3 ± 7.7 years were recruited. MLF depended on the screen size (P = .0004; Kruskal-Wallis) and increased with CRDP use, especially in challenging tasks, such as restraining the smallest screen. The highest MBF was found in dentate participants (P < .0001; Mann-Whitney). Analysis of variance (ANOVA) showed a global significant difference in masticatory performance between groups, with PRDP patients chewing better than CRDP patients. Dental state, time lapse since last tooth loss, and MBF predicted masticatory function. CONCLUSION Tooth loss significantly affects MBF and masticatory performance. Free-end saddles with a rotational axis in two-implant IODs and Kennedy Class I PRDPs may limit MBF and consequently masticatory performance. CRDP design should facilitate perioral muscular function.

The main purpose of the present study is to prove the usability of a mechanism with a common rotational axis during twisting manipulation using a multi-fingered robotic hand where two fingers and two other fingers can independently rotate in inner and outer circles with a dual turning mechanism. Although various types of conventional multi-fingered hands have potential capability to achieve twisting manipulations such as opening a bottle cap from within a hand, it is well-known that such tasks are difficult to execute quickly due to limited working space of the fingers and complexity of control. The proposed hand with a common rotational axis is effective in rotational manipulation around a particular axis, where each joint role assignment is completely decoupled into internal force control for grasping an object and velocity control around the axis for rotating the object. We prove the usability of this mechanism with a common rotational axis through the use of a control scheme, and show experimental results involving manipulation tasks where twisting manipulation is dominant.

It has been demonstrated that the torsional patterns of the metatarsal heads are associated with the presence or absence of the medial longitudinal arch in hominoid feet. The relatively untwisted second metatarsal is unique in humans, but that of the African apes is much more inverted, suggesting that the torsion of the second metatarsal might represent the overall shape and flatness of the foot. Some clinical studies have recently argued that the onset of foot pathologies such as hallux valgus might be related to the torsional pattern of the metatarsals. However, to date, no studies have systematically investigated the morphological variations of the torsional patterns of human metatarsals. In this study, therefore, the aim was to clarify the age- and sex-associated variations in the torsional patterns of human metatarsals using three-dimensional computed tomography. The torsion angles of the five metatarsals were calculated by defining the dorsopalmar vector of the metatarsal base and the vector corresponding to the rotational axis of the metatarsal head. The present result demonstrated that the second metatarsals of females were significantly more inverted with increasing age. Flat foot is known to be most common in elderly women. Whether there is a cause-effect relationship between second metatarsal torsion and flattening of the medial longitudinal arch has yet to be answered, but this study suggested that torsion of the second metatarsal might possibly be used as an indicator for the early diagnosis of flat foot and associated foot pathologies. Clin. Anat. 30:1058-1063, 2017. © 2017 Wiley Periodicals, Inc.

Inner-and-outer steel flange has gained many attentions in China. This type flange has both inner and outer rings, as well as bolts. To gain insight into the intrinsic characteristics of the flange, an experimental study is conducted, taking into account that the tension and bending loads are imposed simultaneously. The varying of relative displacement between two adjacent flange planes with external loading is surveyed. It is indicated that the deformation is almost linearly increased with the external loads, if there is no yielded bolt. Strain gauges are employed to capture the strain distribution in the ribs as well as the tube. The internal tension force of bolt is also measured in the test. It is revealed that the failure mode of the flange is the breaking of the outer bolts. Moreover, the existence of the tension load would reduce the bending bearing capacity of the flange, and prying force could be ignored. It is concluded that the plane-section assumption holds approximately. Accordingly, formulas are given to compute the bearing capacity of the flange. It is found that the computing method is quite conservative if the position of rotation axis takes a value of 0.8 times of the diameter of the steel tube.

Parallel mechanisms (PMs) having three translational (T) and one rotational (R) movement capability draw continuous attention from academia and industry. The existing 3T1R PMs can only generate Schoenflies motion and bifurcation of Schoenflies motion. This paper proposes a new 3T1R motion that features one rotation about a varying axis plus three pure translations. Drawing mainly on finite screw theory, a hierarchical approach for type synthesis of limb structures of the PMs having 3T1R motion with variable rotational axis is presented by developing the basic limb bonds first and then their equivalent substitutions using the properties of screw triangle product. The assembly conditions for the PMs of this kind are discussed. Consequently, numerous novel PMs consisting of four identical limbs are synthesized using this technique.

Simultaneous 5-axis control machining is used to machine components in complex, deep grooved shapes. In order to maintain actual feed rates in this kind of machining, it is vitally important to secure continuity in the movement of the rotational axis. When the tool reverses its direction of travel, however, its axis of rotation is liable to make sudden movements. In this study, therefore, we first derive candidate tool postures that can meet the conditions for relative postures to machined surfaces while avoiding tool interferences. We then develop a method for automatically planning continuous changes in the command values of the rotating axial angles in the machine coordinate space.

Surgeon-dependent factors such as optimal implant alignment of the tibial component are thought to play a significant role in the outcome following primary total knee arthroplasty (TKA). In addition, tibial component malrotation is associated with pain, stiffness, and altered patellofemoral kinematics in TKA. However, measuring tibial component rotation after TKA is difficult. Therefore, the purpose of this study was to find a reliable method for positioning the tibial component in TKA. To investigate the morphology of the tibial plateau, 977 patients' knees (829 females and 148 males) were evaluated using MRI. The relationships between the femoral transepicondylar axis (TEA), Akagi line, posterior tibial margin (PTM), medial third of the tibial tubercle (MTT), and anatomical tibial axis (ATS) were investigated in this study. In addition, gender difference in tibial rotational alignment were evaluated. Relative to the TEA, the MTT and ATS were externally rotated by 0.5° ± 4.4° and 0.5° ± 5.4°, respectively, while Akagi line and PTM were internally rotated by 3.7° ± 4.5° and 9.9° ± 6.1°, respectively. Gender differences were found in MTT, Akagi line and ATS (P

Kilovoltage rotational radiotherapy of breast cancer has been proposed as an alternative procedure to the conventional breast radiotherapy with 6 MeV photon beams. The use of orthovoltage X-ray tubes rotating around the breast, instead of conventional medical linear accelerators, would allow for significant reduction of acquisition and management costs. However, the employment of an X-ray tube limits the maximum available photon flux: a synchrotron radiation source could provide a high dose rate, but its clinical use is prevented by the size of such a source. In this work, we propose the use of the BriXS twin Compton pulsed X-ray source as a compact alternative to the synchrotron radiation source, for kilovoltage radiotherapy of breast cancer. This proposed source presents a footprint of 40 m × 20 m, and the X-ray spectrum presents a mean energy of 88 keV with a suitable photon flux. The dose distribution in a simulated radiotherapy session was computed via a Monte Carlo software based on the Geant4 simulation toolkit. The study focused on the skin dose ratio, i.e. the percent ratio between the dose to the skin and that to the tumor volume in the modelled breast. A low skin dose allows for a suitable sparing of skin tissue during radiotherapy. For a cylindrical model breast with a diameter of 140 mm embedding a spherical simulated lesion with a diameter of 10 mm placed at the rotational axis of the cylinder, the calculated skin-to-tumor dose ratio was as low as 7%.

Successful implementation of a catheter-based imaging system relies on the integration of high-performance miniaturized distal end optics. Typically, compensation of chromatic dispersion, as well as astigmatism introduced by the device’s sheath, can be addressed only by combining multiple optical elements, adversely impacting size and manufacturability. Here, we present a 300 × 300 × 800 μm(3) monolithic optic that provides high optical performances over an extended wavelength range (near UV-visible-IR) with minimal chromatic aberrations. The design of the optic, fully optimized using standard optical simulation tools, provides the ability to freely determine aperture and working distance. Manufacturing is cost effective and suited for prototyping and production alike. The experimental characterization of the optic demonstrates a good match with simulation results and performances well suited to both optical coherence tomography and fluorescence imaging, thus paving the way for high-performance multimodal endoscopy systems.

Tibial tubercle-trochlear groove (TT-TG) distance is associated with a greater risk of recurrent patellar dislocation in young, active patients. However, the effect of TT-TG distance after total knee arthroplasty (TKA) has not been investigated. The purpose is to analyze the effect of TT-TG distance and component rotation on patellar tilt and patellar shift after TKA.After TKA, axial computed tomography scans and axial radiograph were taken in 115 consecutive knees. TT-TG distance was measured between the most anterior point of the tibial tuberosity and the deepest point of the femoral component relative to a line connecting the anterior condyles. Femoral and tibial component rotation was measured relative to the femoral and tibial rotational axis, respectively. Pearson correlation coefficients were calculated.TT-TG distance had a significant correlation with patellar tilt in extension (R = 0.220, P = .018), patellar tilt in flexion (R = 0.438, P.001), and patellar shift (R = 0.330, P.001). Tibial component rotation had a significant correlation with patellar tilt in flexion (R = -0.251, P = .007) and patellar shift (R = -0.360, P.001). Femoral component rotation had no significant correlations. Tibial component rotation had a significant correlation with TT-TG distance (R = -0.573, P.001), whereas femoral component rotation had no correlation (P = .192).TT-TG distance had a significant correlation with patellar tilt and patellar shift. Surgeons need to understand the factors affecting TT-TG distance and to pay attention to avoiding excessive TT-TG distance after TKA.

Given the design of the Helical TomoTherapy device, the patient's central axis is routinely aligned with the machine's rotational axis to prevent the patient's body from colliding with the machine walls. However, for treatment of tumors located away from the patient's central axis, this position may not be optimal as the adequate radiation dose may not reach the affected site. Our study aimed to investigate the influence of tumor location on dose quality and delivery efficiency of tomotherapy plans. A phantom and 15 patients were selected for this study. Two plans, A and B, were implemented for each case. In plan A, the patient's central axis was aligned with the machine's rotational axis, whereas in plan B, the center of the planning target volume (PTV) was aligned with the machine's rotational axis. Both plans were optimized with the same planning parameters, and the dose quality of the plans was evaluated using dosimetrics. The delivery efficiency was determined from delivery time and monitor units (MUs). A paired t-test or nonparametric Wilcoxon signed-rank test was performed for statistical comparison. In the phantom study, the median delivery times were 358 and 336 seconds for plans A and B, respectively, and this difference was significant ( p = 0.005). In the patient study, the median delivery times were 348 and 317 seconds for plans A and B, respectively, and this difference was also significant ( p = 0.001). The dose qualities of both plans for each patient were nearly identical. No significant differences were found in the conformal index, heterogeneity index, and mean dose delivered to normal tissue between the plans. Both phantom and patient studies showed that for normal-sized patients, the delivery time reduced as the distance between the PTV and the patient's central axis increased when the PTV center was aligned with the machine axis. In conclusion, aligning the PTV center with the machine's rotational axis by shifting the patient during tomotherapy reduces the delivery time without compromising the dose quality of intensity-modulated radiation therapy.

Background: The origin of femoral maltorsion is often unknown. However, defining the origin of the rotation of the femoral maltorsion can be useful for establishing the most suitable point to do an external derotational osteotomy. Previous studies have not considered the femoral diaphysis in their investigations of the origin of the deformity. The study of the whole morphology of the femur with 3D volumetric tools, including the femoral diaphysis can contribute to a better understanding of the behavior of femoral maltorsion. Methods: An atypical case of unilateral femoral anteversion was selected. Both femurs were used to obtain 3D bio-models. The mirror image of the asymptomatic side was obtained and overlapped with the symptomatic femur. The Hausdorff&ndash, Besicovitch method was used to evaluate the morphologic discrepancies (in mm) between the two femurs in three zones: (1) the femoral neck, (2) the proximal diaphysis, and (3) the distal diaphysis. The differences between the two femurs were analyzed and its correlation was statistically defined using a lineal regression model. Results: The deformity in the distal diaphysis increased from the supracondylar area until the apex of the antecurvatum angle (R2 = 0.91) and then decreased until the base of the femoral neck (R2 = (&minus, 0.83)), to finally increase significantly in the femoral neck area (R2 = 0.87). All of the correlations were statistically significant (p-value ˂ 0.001). Conclusion: The femoral maltorsion originates in the supracondylar area and its rotational axis is the longitudinal axis of the femoral diaphysis. Even though the deformity affects the femoral diaphysis, its clinical relevance is much higher in the femoral neck since the rotational axis passes through its base. Thus, the osteotomy can be conducted along all of the femoral diaphysis as long as it is done perpendicular to it.

The Runout of a shaft is defined as the deviation of the measured surface from an ideal circle rotating around its rotational axis. The total runout can be split into two main components: the mechanical and the electrical runout. The electrical runout depends on the metallurgical state of the shaft which can only be altered to a certain degree after the forging and heat treatment processes are finished. Especially large shafts for electric motors are prone for high electrical runout, because material imperfections are moved to the center of the shaft by the forging process. As there is an unfavorable ratio between bearing diameter and the largest diameter of the shaft, these imperfections will be in the area of the new shaft surface after machining. Statistics have proven that material inhomogeneity generating an electrical runout occurs in almost all kinds of steel. This paper will provide some information about how to eliminate uncertain material properties causing the electrical runout. One measure will be presented in detail including test results.

A simple cyclic elastoplastic constitutive model for sand is proposed based on the UH model for overconsolidated clay. The proposed model has the following features. First, in order to describe the stress-induced anisotropy in sand, a rotational hardening rule is introduced for the evolution of the yield surface axis with development of plastic deviatoric strain in the principal stress space. Second, the relationship between the rotational axis and stress-induced anisotropy is modeled by introducing the slope of rotational axis into the yield function. The flatness of the yield surface can be determined by the slope of rotational axis. Finally, a revised unified hardening parameter is proposed to incorporate the stress-induced anisotropy. The model capability in describing the cyclic response of sand is verified by comparing the simulations with available test results.

The relationship between the surgical epicondylar axis (SEA) and the rotational axis of the distal femur remains unclear. We investigated the relationship between the SEA and the distal femur and whether the SEA can be used as the rotational axis of the knee. Angular and linear measurements of 70 femora at 0°, 30°, 60°, 90°, and 120° of flexion were recorded. Results showed that the SEA was a logical and appropriate parameter as a principal axis for knee flexion at least between 0° and 60° of flexion. The study has important implications for the design and positioning of femoral components in total knee arthroplasty.

This paper presents a new error measurement method, a Dual Optical Path Measurement Method (DOPMM), to identify error parameters of the rotational axis of a machine tool along its error sensitive directions. The method development was carried out on a motorized rotary stage equipped with a Doppler laser instrument. An error measurement experiment and a machining experiment were conducted on a five-axis machining center with a titling rotary table. It was found that the DOPMM can identify all of the six volumetric error parameters with the simple algebraic operations. Compared with the existing ball bar tests, which need a mathematical error modeling of machine tools to separate the error parameters, the identified process of DOPMM is more simple and easier to understand. And the operation of machine tools during the measurement is much easier than that of the existing ball bar tests. The experimental results showed that the part precision can have a significant improvement of 68% when the identified error parameters are used for error compensation. Hence, the measurement method established in this study is sensible and efficient, and could be used for the error compensation on a wide range of machine tools to improve their machining precision.

Background In clinical practice, clubfeet feel stiffer compared to healthy feet. Furthermore, the clinical impression is that stiffer clubfeet have a higher tendency to relapse. Until now, no objective measure has been available to determine the stiffness of clubfeet. The goal of the current project was to objectively quantify ankle and subtalar joint stiffness in clubfeet patients and to compare this stiffness between clubfeet patients and healthy controls using a newly developed measurement device. Methods The newly developed Torque-Displacement-Handpiece in combination with an adjusted Abduction Dorsiflexion Mechanism clubfoot-brace, made it possible to move a foot over two rotational axis, while continuously capturing the applied torque and the achieved angulation. Based on this information, stiffness of the ankle and subtalar joint were assessed for 11 clubfoot patients with 17 clubfeet and 11 healthy subjects with 22 healthy feet. Findings With the Torque-Displacement-Handpiece measuring device it was possible to measure torque, angulation and stiffness in a reliable and precise manner. Clubfoot patients showed less angulation and a higher stiffness for measurements over the ADM subtalar axis compared to controls. After adjusting for shoe size, the stiffness for measurements over the ADM tibiotalar axis was also significantly higher in clubfeet than controls. Interpretation Overall, these results indicate that clubfoot patients have a higher ankle and subtalar joint stiffness in the affected joint compared to healthy controls. In the future, the Torque-Displacement-Handpiece could be used to monitor stiffness of clubfeet during treatment, and as such, play a potential role in the early detection of relapsing clubfeet.

Purpose Ear position contributes significantly to facial appearance. However, while objective measurements remain the foundation for esthetic evaluations, little is known about how an ear should ideally be positioned regarding its rotational axis. This study aimed to further evaluate whether there exists a universally applicable ideal ear axis, and how sociodemographic factors impact such preferences. Materials and methods An interactive online survey was designed, enabling participants to change the axis of a female model's ear in terms of its forward and backward rotation. The questionnaire was sent out internationally to plastic surgeons and the general public. Demographic data were collected and analysis of variance was used to investigate respective preferences. Results A total of 1016 responses from 35 different countries (response rate: 18.5%) were gathered. Overall, 60% of survey takers chose the minus 10 or 5° angles to be most attractive. Significant differences were found regarding sex, ethnicity, country of residence, profession and respective ear axis preferences. Conclusion Across multiple countries and ethnicities, an ear position in slight reclination of minus 5–10° is considered most pleasing in Caucasian females. However, sociodemographic factors significantly impact individual ear axis preferences and should be taken into consideration when performing reconstructive ear surgery.

“Origami” is an art of paper-folding. Recently, origami has been applied to the design of foldable robot structure. There are various folding techniques including the one we studied — Miura-ori. We designed a Miura-ori of non-zero thickness that 1) was made from rigid materials (rigid origami), and 2) contained self-similar units (modular origami). Our design has a maximum thickness of 6 mm, but can be folded up to 180° (complete fold)—equivalent to a zero-thickness origami. In this paper, we presented a novel design of rigid, foldable, modular origami, as well as derived constraints of joint design that enable a complete fold. Moreover, neodymium magnets were placed in the cores of each rotational axis in certain patterns. This not only allows for the structure to have characteristics of self-folding or self-unfolding, but also gives us the ability to control this robot structure using a current-induced magnetic field. When the magnetic field is on, the robot can switch from an unfolding position to a folding position. Such feature presents a potential for this structure to be used as a dynamic “spring” with an adjustable stiffness. This adjustability could be achieved by varying the input current applied to generate the magnetic field. Another application of this mechanism includes reducing shocks, and vibrations that are perpendicular to the structure.

The solar field of a central receiver system (CRS) is an array of dual-axis tracking heliostats on the ground beside or around a central tower, with each heliostat tracking the sun to continuously reflect the solar beam onto the fixed tower-top receiver. Azimuth–elevation tracking (also called altitude–azimuth tracking) is the most common and popular tracking methods used for heliostats. A general azimuth–elevation tracking angle formula was developed previously for a heliostat with a mirror-pivot offset and other typical geometric errors. The angular error parameters in this tracking angle formula are the tilt angle, ψ t , and the tilt azimuth angle, ψ a , for the azimuth axis from the vertical direction, the dual-axis non-orthogonal angle, τ 1 (bias angle of the elevation axis from the orthogonal to the azimuth axis), and the non-parallel degree, μ , between the mirror surface plane and the elevation axis (canting angle of the mirror surface plane relative to the elevation axis). This tracking angle formula is re-rewritten here as a series of easily solved expressions. A more numerically stable expression for the mirror-center normal is then presented that is more useful than the original mirror–normal expression in the tracking angle formula. This paper discusses some important angular parametric properties of this tracking angle formula. This paper also gives an approach to evaluate the tracking accuracy around each helistat rotational axis from experimental tracking data using this general tracking angle formula. This approach can also be used to determine the heliostat zero angle positioning errors of the two rotational axes. These supplementary notes make the general azimuth–elevation tracking angle formula more useful and effective in solar field tracking designs.

In order to understand the characteristics of fire whirls in the inclined shaft with corner gap, large eddy simulations (LES) of thermal flow field in a 9-meter-high inclined shaft were employed. In the inclined shaft, the conrner gap is 0.3m and 0.7m in width, and the inclination angle is 5°, 30°, 45°, 50° and 55° from the vertical orientation axes respectively. It is found that a whirling flow field could be formed under proper inclination angles and corner gap width. Rotational axis of fire whirls in the inclined shaft would have same inclination angles with the shaft. Similar to the case of fire whirls in a vertical shaft, the width of corner gap of inclined shaft also influences the whirling motion of the flame. In this paper, for the same fire and inclination angle, the 0.3-meter-wide corner gap is easier to form stable fire whirls than the 0.7-meter-wide corner gap. By comparison with buoyancy, the slightly greater Coriolis force was found above a height 3m for inclined fire whirls when the width of croner gap is 0.3m, however, the Coriolis force acts only on the lower part of the shaft when the width of croner gap is 0.7m.

This paper presents how in the Reverse Engineering process can be integrated specific software tools, developed by the authors, which allow for digitized rectangular parts with internal surfaces of revolution, to obtain solid models and CNC program. The first tool named Rotational Axis Primitives and Recognition has implemented a set of algorithms and it is used for recognizing, from a cloud of points associated with a rotational part, the axis and geometrical parameters. The second tool named Hole_Application is created for forward engineering and it can be used to design and manufacture the industrial products with rectangular shape using intelligent technological objects for holes.

Anthropomorphic arm manipulators usually consist of as a series of revolute joints and links. In this paper, serial-chain manipulators are described by a novel kinematic representation using a series of type R or T joints, which are classified according to relation between a rotational axis and two adjacent links. It provides an easy intuition to describe general types among existing manipulators and also to get intuitive ideas before designing of joint and link modules of modular manipulators. From these intuitive idea about joint configurations using two types of joints, a new concept of joint module with two input and one output connections is presented. This joint module enables to couple directly between two joint modules. In addition, practical solutions of mechanical and electrical connections between joint or link modules is introduced. The connection can be established between two modules via eight types of relative positions of 45 degree intervals. Using joint and link modules, 3-DoF(Degrees-of-Freedom) modular manipulators of three kinds of joint configurations are shown representatively. After assembly, the standard D-H(Denavit-Hartenberg) parameters of three examples are obtained utilizing information of joint and link modules.

Exposure to microgravity causes a head-ward fluid shift that current spaceflight countermeasures fail to fully ameliorate. Artificial gravity (AG) through short-arm human centrifugation (SAHC) has been proposed as a possible countermeasure. Whilst the responses to increasing g-levels have been well characterized, the effects of a shift in rotational axis position (RAP), independent of g-level (at the feet), are not known. We hypothesized that a shift in RAP to in-body rotation (IBR) at heart-level, with a comparable g-level at the feet, would have a beneficial effect on g-tolerance through a supported cerebral perfusion from head-ward arterial pressure increases and a changed gravitational gradient. To test our hypothesis we performed a study with twenty (10 male; 10 female) healthy participants (mean ± SE; age: 26.2 ± 0.9 yrs and BMI: 22.9 ± 0.4 kg.m−2) who underwent passive short-arm centrifugation, in which profiles were randomized, for periods of 10 min five times per day on two separate days, two months apart. Each centrifuge profile consisted of one of three centers of rotation (either above the head — P1; apex of the head — P2 or IBR at heart-level — P3) at one of three different g-levels (either 1.0 gz — G1; 1.7 gz — G2 or 2.4 gz at the feet — G3). Cerebral perfusion (cerebral near-infrared spectroscopy for tissue saturation index, cTSI), central volume loss (strain gauge plethysmography for calf circumference, CC) and cardiovascular response for heart rate (HR) were all continuously measured. G-tolerance to each position was obtained by recording the number of participant centrifuge runs with pre-syncopal symptoms (PSS). Preliminary data suggest that centrifugation about the heart (P3) was more tolerable with a larger proportion of participants not experiencing PSS despite being exposed to the same g-level at the feet in other positions (P1 and P2). Currently within the literature, magnitude of centrifugation as an index of g-stress is quantified by g-level experienced at the feet only. However, within this present study we show that g-level alone is an insufficient method to classify degrees of artificial gravity (AG). The differences in tolerance to both long- and short-arm human centrifugation (L- and SAHC) are thought to arise due to differences in their respective gravitational gradient. Results of this study clearly demonstrate that placement of the rotational axis during centrifugation deserves more attention than previously thought.

Recently, the idea of sustainable development has become more and more important. In the previous report, we focus on downsizing industrial goods and discuss the environmental load of industrial goods. As a result, by downsizing machine tools we verified that the environmental load of mother machines in making copies of themselves could be reduced. On the other hand, we verified that the environmental load of use of the machine itself increased relatively. Thus, in desktop machine tools, we verified that reducing the environmental load of use of the machine itself would increasingly become an issue in the future. In this paper, we discuss methods of using desktop machine tools from the aspect of power consumption. As a result, we verified that in cutting along the linear-axis and rotational-axis, we have to consider back clearance after cutting.

Calibration of an X-ray imaging system involves estimation of the 3D geometrical configuration of the system components. Here, we propose a calibration method for stereo X-ray imaging systems, which capture two X-ray images at two orthogonal positions. The calibration parameters include the relation between image coordinates and world coordinates, the relative 3D positions of the X-ray source and detector, and the rotational axis of the stereo X-ray system. The average error of the proposed calibration method was determined to be approximately 0.03% in evaluation tests.

The robot joints are usually rotational axis by two link joints, bionic features is not strong. The shortcomings of intelligent MR damper control multi-axis bionic knee can only provide resistance and certain sizes of regain momentum, cannot provide larger power, therefore this paper gives by the multi-axis four-bar structure, ball screw transmission hybrid drive multiaxial bionic active knee institutions. And analysis the human leg institutions and commonly used two-bar structure, solve the ball screw transmission installation location parameters. And established based on hybrid drive of the bionic active the knee's virtual prototype.

The purpose of this study is to propose a lying location on a gatch bed for bedridden elderly people or patients, in order to decrease pressures around the abdominal region during backrest lifting. A proposed lying location is defined as the location where an ischial tuberosity of the patient is positioned right above the rotational axis of the backrest. A patient dummy has been developed to directly measure the abdominal pressures. Experiments were carried out to verify the effects of the proposed lying location during the backrest lifting and lowering. The pressures and slipping displacements were measured using the developed patient dummy in the conventional and proposed lying location. As a result the pressures and slipping displacements were decreased in the proposed lying location.

Total knee arthroplasty has an excellent track record for improving quality of life, allowing greater independence and reducing pain in both primary and secondary osteoarthritis knee. Its efficacy depends mainly upon proper alignment of femoral and tibial component. The alignment should be proper in all the three planes frontal, sagittal and axial. The rotational axis refers to the axial plane. Errors in positioning the femoral component in the axial plane are the cause of patellofemoral complications, ligamentous instability and disturbed joint kinematics. There are many CT scan studies measuring distal femur rotational axis, while our study was done using MRI measuring distal femur rotational axis between right and left knee of an individual.

Seven cricket bats, four standard and three significantly different designs, were tested for a set of mechanical properties: equivalent bending stiffness, moment of inertia, and freely-suspended vibration. These properties are known to be related to the performance of the cricket bats in terms of pick up weight, vibrations imparted to the batsman, and energy imparted to the cricket ball. The aim of this work was to determine whether these novel designs improve the bat’s performance parameters. Intuitively correctly, results showed that by redistributing the mass of the bat further away from the rotational axis the moment of inertia increases. This results in an increase of the ball’s rebound speed after collision. Carbon fibres inserted in the handle of the bat were found to improve its vibrational performance and provide the advantage of having a stiffer blade combined with a relatively less-stiff handle, which is an optimum for imparting maximum energy to the ball.

The purpose of reverse engineering is to convert a large points cloud into a CAD model. Parameters extraction for rotational surface from measure data is an important problem in reverse engineering. Rotational axis is a crucial parameter of rotational surface. In this paper, random sampling consensus algorithm combined with Least-Squares method is used to extract the rotational axis of rotational surface. Experimental results show effectiveness, robustness and accuracy of this proposed approach.

Micro machining by wire electrical discharge machining (WEDM) has become prosperous owing to its ability to machine conductive, exotic and high strength and temperature resistive (HSTR) materials with the scope of generating intricate shapes and profiles. In order to achieve the very high accuracy micro machining, one of the key factors is the preparation before actual machining. According to the authors' experiences and studies in micro machining by WEDM, for the first time, this paper introduces the preparation process for WEDM in micro machining. From the gauge setup, wire alignment adjustment, working coordinate setup to calibration method for rotational axis, the preparation process has been studied and introduced in detail, which forms the solid basis for high accuracy micro machining by WEDM. Experimental results show the accurate geometrical features can be fabricated based on the proposed preparation process.

Considering gyroscopic effect and flexibility of the shaft, the eight freedoms dynamic model is established. The dynamic characteristic and control quantity in different bearing rigidity and rotation axis are studied and discussed by optimal control theory. Furthermore, the controlling and the responding are discussed. The simulation results show that the bearing rigidity has great effect on the control quantity so that the elasticity of bearing must be considered. The asymmetry rigidity of rotational axis has little influence on stability. The conclusion may bring up theoretical references for precision control for rotor magnetic bearing system.

Data on the pulse structure and variations of the linear polarization angle at frequencies near 1 GHz have been used to estimate the angles β between the rotational axis and magnetic moment of the neutron stars assocaited with 80 pulsars. The calculations applied several methods. The minimum values of β were estimated from the observed pulse width W10 at the 10% level for the entire sample. Maximum estimates of β were obtained for six sources with small polarization position angle derivatives. Equations for the angle β were derived for various forms of the observed profile, and solutions obtained for 34 pulsars. The β values calculated using different methods are compared. For three pulsars with known interpulses, the obtained values of β demonstrate that two (PSR B1055-52 and PSR 1822-09) are aligned rotators, whereas the other (PSR B1702-19) is an orthogonal rotator. A search for interpulses and interpulse emission in PSRB1641-45, PSR1642-03, and PSR 1944+17 is necessary, and a search for an interpulse at 180° from the main pulse is required in PSR B2321-61.

The physicist Damian Kreichgauer entered the German Missionary Order Societas Verbi Divini (SVD) in 1892. From 1895 onwards, he taught natural sciences to future missionaries at the Order's seminary St Gabriel (Austria). In 1902, he published a book called Die Äquatorfrage in der Geologie (The Question of the Equator in Geology) with the Order's publishing outlet, in which he advocated the idea of a mobilistic Earth, where the Earth's crust as a whole moved with respect to the fluid core and the Earth's rotational axis. The main evidence for this idea he found in the changing of climate zones during geological epochs. Due to a small database, which was basically restricted to European plate localities, Kreichgauer did not notice discrepancies between polar wander on different continents. Nevertheless, the book was later cited and discussed as one of his precursors by Alfred Wegener in his book on the origin of continents and oceans. Kreichgauer also introduced his ideas to parallel the events of the biblical Genesis with geological epochs. He later expanded this ‘concordance theory’ in a separate book Das Sechstagewerk (The Work of the Six Days). He eventually abandoned scientific work, possibly due to censorship wielded by the Superior of his Order, unlike his contemporary, the Jesuit Erich Wasmann, a respected entomologist, who defended evolutionary ideas despite adverse Church politics and censorship.

Analysis of Titan’s hemispheric brightness asymmetry from mapped Cassini images reveals an axis of symmetry that is tilted with respect to the rotational axis of the solid body. Twenty images taken from 2004 through 2007 show a mean axial offset of 3.8 ± 0.9° relative to the solid body’s pole, directed 79 ± 24° to the west of the sub-solar longitude. These values are consistent with recent measurements of an implied atmospheric spin axis determined from isothermal mapping by [Achterberg, R.K., Conrath, B.J., Gierasch, P.J., Flasar, F.M., Nixon, C.A., 2008. Icarus 197, 549–555].

Truing and dressing are essential processes of grinding wheel preparation. They make the wheel geometry true with respect to its rotational axis and its cutting surface sharp. These factors significantly influence the quality of the final profile and surface produced from the grinding process. Prediction of the optimum wheel surface for grinding, defined as one which produces an accurate profile and cuts most efficiently can greatly minimize the time to optimize grinding wheel performance. This paper describes virtual dressing and truing operations, takes under account vibration of the dressing apparatus and shows how to generate wheel surface replica under different conditions.

The rotational system of an automatic washing machine has two major technical difficulties. One is the collision of the tub against the frame at the beginning of its early spinning stage. A factor that causes such instability of the rotational object can be attributed to the deflection of the liquid inside the liquid balancer due to the unbalance mass. This study proposes the installation of a middle plate to avoid the deflection of the liquid and a CFD method is used to verify its effectiveness. The other is the whirling vibration occurred during the high speed rotation of the basket and it shakes the center of its rotational axis. This is because the balancer cannot generate enough restoration forces during its high speed rotation. It is necessary to employ the multi-race in the balancer in order to increase restoration forces. The analysis for the configuration has been performed using a dynamic model.

Two patients showing two rotational axes of their positional nystagmus had canalolithiasis in bilateral posterior semicircular canals (PSCCs), leading to the diagnosis of true bilateral benign paroxysmal positional nystagmus (P-BPPN). Another 18 patients had a single rotation axis of their positional nystagmus with short time constant (TC) on one side and long TC on the other. Since canalolithiasis in the uppermost PSCC may be transient cupulolithiasis, evoking positional nystagmus with long TC, the diagnosis of the latter patients should be pseudo-bilateral P-BPPN.To differentiate the true bilateral posterior canal type of P-BPPN from pseudo-bilateral P-BPPN.The rotational axis and TC of positional nystagmus were three-dimensionally analyzed in 20 patients showing geotropic torsional nystagmus on the left and right Dix-Hallpike (D-H) maneuvers.Two patients showed two rotational axes of their positional nystagmus, which were perpendicular to the plane of the PSCCs. There were no differences in TCs of their positional nystagmus between bilateral D-Hs. Another 18 patients showed a single rotational axis of their positional nystagmus, which was perpendicular to the plane of either the left or right PSCC. TCs of their positional nystagmus were short on one side and long on the other.

The cone frustum machining test prescribed in NAS979 is only one method that is used in world wide to evaluate the machining accuracy of five-axis machine tools. The issue is that the test parameters are not defined in the machining by using five-axis machine tools with tilting table. The motion of each axis depends on the location of a workpiece, and the workpiece location is an important factor for the evaluation. In this paper, the influence of the workpiece location for five-axis machine tools with tilting table is analyzed, and it is shown that the accuracy of machined cone frustum varies due to the workpiece location and the influence of the geometric errors in the five-axis machine tool. The proper location to evaluate the geometric errors is also proposed.

The unbalanced mass of a high precision rotor deteriorates mechanical performance of the rotor. The geometrical center of a rotor generally corresponds to the rotational axis of the rotor. However, this alignment carried out with a stationary rotor does not guarantee the dynamic rotor balance. There have been a number of schemes for the correction of the unbalance published for decades especially in the hard drive industry where the issues are directly affecting manufacturing costs and product performances. Realizing the significance of the problem, the present work tries to refine one of the methods that works by applying external impact during a rotor spins. A systematic way to apply the external impact to a rotating rotor has been introduced to minimize unbalance correction process time.

This study focuses on the measurement and evaluation of tactile sensations of various fabrics. First, tactile data on six pieces of underwear and seven pieces of polo shirts are collected through a questionnaire and the dominant factors of feelings of wearability are determined through factor analysis. Next, a tactile sensor with a polyvinylidene fluoride (PVDF) film as the sensory receptor and a sensor apparatus are assembled. The base of the sensor is an aluminum cylinder, around which a rubber sponge layer, a PVDF film, a protective layer of acetate film, and lace are stacked in sequence. The sensor is set on the rotational axis of a motor and a measurement object is placed on the sensor. Then, the sensor is turned to collect tactile information on the object. Features of the collected data are extracted by calculating the average amplitude of low frequency signals, the variance of sensor output, and the power intensity in a medium frequency range. Comparison with the results shows that the PVDF sensor well describes the human tactile perception.

This paper presents the Ultra Precise Gear Measuring Instrument/UPGMI, which can measure individual deviations of the gear with sub-micron meter resolution. Highly stabilized measurements of the ultra precise and very fine/minute gears are indispensable in order to miniaturize machine and its components. To meet with these purposes, a new basic concept of the main spindle of rotational axis, carrying test gear, with vertical travel/motion was employed in UPGMI. The result of theoretical study for the error factors caused from the basic axis formation shows the UPGMI construction has less error factors compared with the current typical measuring instruments. Then calculation for error allowance distribution to each mechanism for axis movement was made. We could achieved the accuracy of measurement in submicron order even at preliminary assembled UPGMI.