Static Orientation Research Articles

Effect of stretching orientation on the crystalline structure and energy storage properties of poly(vinylidene fluoride) films

Poly(vinylidene fluoride) (PVDF) with a high content of β phase shows great potential for applications in the pulse energy storage field because of its high dielectric constant and breakdown strength. The stretching process can significantly induce the crystal phase transformation and change the structure of the aggregated state. To deeply investigate the influence mechanism of the fabrication process, solution casting (SC), melt stretching (MS), static biaxial orientation (SBO), and continuous biaxial orientation (CBO) were used to fabricate PVDF films. The essential difference between the four technological routes lies in the different forms of tensile orientation imposed. Stretching perpendicular to the machine direction promotes the transition of the original α phase crystals to the β phase. Stretching orientation can regulate the crystalline phase structure of the film and its applicability. The relative fraction of β phase crystals in the PVDF-CBO film reaches 84.1 %, resulting in a much higher dielectric constant (12.22 @1 kHz) than that of the PVDF-SC film (7.16). The continuous biaxially oriented PVDF exhibited excellent insulation properties with a breakdown strength of 759.21 kV/mm. Meanwhile, the CBO film obtained an energy storage density of 16.76 J/cm3 with a charge-discharge efficiency of 80.13 % at 675 kV/mm. This work is of great scientific significance for the in-depth study of the influence of different film-forming processes on the internal structure of films, ranging from laboratory fabrication to industrialized production.

Estimating ski orientation using IMUs in alpine skiing

Ski-snow interaction is the essential component of alpine skiing. To understand how a skier manipulates his ski to turn, we need to develop methods to measure the orientation of the ski throughout a complete run. Recent studies tried to use IMUs to estimate edge angle (EA) during skiing. We introduce and validate a method on how to calibrate and employ IMUs to precisely and accurately measure roll angles (RA) as a matter of changing orientation of the ski around its longitudinal axis in 3D space during skiing. Static orientation measurements on an inclined plane perfectly correlate (r2 = 1) with 3D motion capturing: RMSE = 0.18° and 0.24° respectively. Bland Altman showed a mean bias of 0.23° (95% CI: -0.16°, 0.63°) and 0.21° (95% CI: -0.3°, 0.73°). Accuracy and drift tests against constant standardised rotational velocities showed no drift behaviour over time, but RA estimation accuracy is reduced with increasing angular velocities (SD @ ±300°/s: 0.57°, max. difference from average at ±300°/s: 2.7°). During skiing on a ski ergometer the comparison of maximum RA against Vicon showed a mean bias of 0.13° (95% CI: -0.86° to 1.1°). Even though ski ergometer skiing has a similar frequency and angular velocity profile like outdoor skiing, there are more rotational degrees of freedom in outdoor skiing. The foundation is provided in this paper. To understand how a skier manipulates the ski on snow and to understand RA and EA progression during a turn in detail, further research should validate the method in the field and additionally look into RA progression within individual turns.

Fluid and Bubble Flow Detach Adherent Cancer Cells to Form Spheroids on a Random Positioning Machine.

In preparing space and microgravity experiments, the utilization of ground-based facilities is common for initial experiments and feasibility studies. One approach to simulating microgravity conditions on Earth is to employ a random positioning machine (RPM) as a rotary bioreactor. Combined with a suitable low-mass model system, such as cell cultures, these devices simulating microgravity have been shown to produce results similar to those obtained in a space experiment under real microgravity conditions. One of these effects observed under real and simulated microgravity is the formation of spheroids from 2D adherent cancer cell cultures. Since real microgravity cannot be generated in a laboratory on Earth, we aimed to determine which forces lead to the detachment of individual FTC-133 thyroid cancer cells and the formation of tumor spheroids during culture with exposure to random positioning modes. To this end, we subdivided the RPM motion into different static and dynamic orientations of cell culture flasks. We focused on the molecular activation of the mechanosignaling pathways previously associated with spheroid formation in microgravity. Our results suggest that RPM-induced spheroid formation is a two-step process. First, the cells need to be detached, induced by the cell culture flask's rotation and the subsequent fluid flow, as well as the presence of air bubbles. Once the cells are detached and in suspension, random positioning prevents sedimentation, allowing 3D aggregates to form. In a comparative shear stress experiment using defined fluid flow paradigms, transcriptional responses were triggered comparable to exposure of FTC-133 cells to the RPM. In summary, the RPM serves as a simulator of microgravity by randomizing the impact of Earth's gravity vector especially for suspension (i.e., detached) cells. Simultaneously, it simulates physiological shear forces on the adherent cell layer. The RPM thus offers a unique combination of environmental conditions for in vitro cancer research.

Poster Session: A unifying framework for perceptual decision-making.

Perceptual decision making (PDM) has been studied using two approaches. Threshold measurement is predominant used in psychophysics, while reaction times (RT) with associated models have been used to estimate components of PDM (i.e., drift rate). To test if these two approaches reflect overlapping mechanisms, we conducted 3 experiments: a motion, a static orientation, and a dynamic orientation task. DT is the shortest stimulus presentation time sufficient to make accurate perceptual decisions. RTs and choices were fitted by a drift diffusion model (DDM). We expected a close relationship between DTs and drift rates, allowing us to accurately predict DTs from RT. In the motion task, we found a close relation between the empirical DTs and the DTs predicted by the DDM. Surprisingly, in the static task, there was little correlation between the two; DTs, improved monotonically with higher contrast, but drift rates saturated at 6%. We hypothesize that this mismatch is due to the information being available immediately in the static task, without needing to accumulate new evidence. Thus, we developed a novel dynamic orientation task that mimics the dynamic nature of the motion task and found a similar relation between DTs and drift rates. In summary, we show a close link between DTs and drift rate for the two dynamic tasks. This result supports the conceptualization of drift rate as a proxy for perceptual sensitivity but only for task where new information becomes available over time.

Poster Session: Evidence for preserved conscious orientation discrimination in perimetrically-blind fields early after V1-damage.

Cortically-blind (CB) patients with stroke damage to the primary visual cortex (V1) lose conscious vision but many exhibit blindsight - the ability to unconsciously detect or discriminate moving or flickering targets inside their blind-fields. However, the prevalence of conscious visual abilities in CB is less clear. Having developed a new method to assess vision inside perimetrically-defined blind fields, we found that >50% of subacute CB patients (<6 months post-stroke) can consciously discriminate global motion inside their blind field. Here, we asked if they can also discriminate orientation of static targets, which do not typically elicit blindsight. In 10 subacute patients, we mapped their intact and blind hemifields using static, non-flickering, 1cpd Gabors across a wide range of luminance contrasts. Blind-field locations were labeled "preserved" if performance was >72.5% correct. Considering overall performance, only 1 participant had preserved static orientation perception in the blind-field. However, this increased to 4 participants when only considering performance at high contrasts (>50%), all of whom reported awareness of stimuli. Thus, early after V1 damage, conscious percepts for oriented, high-contrast, static targets can remain inside CB fields, similar in incidence to global motion discriminations. We are now testing additional patients to assess if these abilities persist into the chronic period and to detail their underlying neural substrates.

3D Prestress Bioprinting of Directed Tissues.

Many mammalian tissues adopt a specific cellular arrangement under stress stimulus that enables their unique function. However, conventional 3D encapsulation often fails to recapitulate the complexities of these arrangements, thus motivating the need for advanced cellular arrangement approaches. Here, an original 3D prestress bioprinting approach of directed tissues under the synergistic effect of static sustained tensile stress and molecular chain orientation, with an aid of slow crosslinking in bioink, is developed. The semi-crosslinking state of the designed bioink exhibits excellent elasticity for applying stress on the cells during the sewing-like process. After bioprinting, the bioink gradually forms complete crosslinking and keeps the applied stress force to induce cell-orientated growth. More importantly, multiple cell types can be arranged directionally by this approach, while the internal stress of the hydrogel filament is also adjustable. In addition, compared with conventional bioprinted skin, the 3D prestress bioprinted skin results in a better wound healing effect due to promoting the angiogenesis of granulation tissue. This study provides a prospective strategy to engineer skeletal muscles, as well as tendons, ligaments, vascular networks, or combinations thereof in the future.

Dynamic Changes in Lumbar Spine Kinematics During Gait May Explain Improvement in Back Pain and Disability in Patients With Hip-Spine Syndrome.

Prospective cohort. Determine if total hip arthroplasty (THA) changes lumbar spine kinematics during gait in a manner that explains the improvements in back pain seen in patients with hip-spine syndrome. For patients with hip-spine syndrome, improvements in both hip and back pain have been demonstrated after THA; however, the exact mechanism of improvement in back pain remains unknown, as no corresponding changes in lumbar spine static radiographic parameters have been identified. Thirteen patients with severe, unilateral hip osteoarthritis scheduled to undergo THA with concomitant back pain and disability were tested at baseline and 6 months after THA. Harris Hip Score (HHS) and Oswestry Disability Index questionnaires were completed; the static orientation of the spine and pelvis were measured on standing radiographs, and lumbar spine kinematics were measured during treadmill walking using a validated measurement system that matched subject-specific bone models created from CT scans to dynamic biplane radiographs. After THA, both the Oswestry Disability Index (36.3-11.3, P <0.001) and Harris Hip Score (55.7-77.9, P <0.001) improved; however, there were no changes in static intervertebral or pelvis orientation. During gait after THA, the overall lumbar spine (L1 to L5) was less lordotic from heel strike to contralateral toe off ( P <0.001), the L4 and L5 vertebra were less anteriorly tilted by 3.9° ( P =0.038) from midstance to contralateral heel strike and by 3.9° ( P =0.001) during stance, respectively. The decreased anterior tilt of the 2 lowest lumbar vertebrae and the corresponding loss of lumbar lordosis may reduce facet loading during the stance phase of gait after THA. This change in lumbar spine kinematics during gait is a potential mechanism to explain the observed improvements in back pain and disability after THA. 4.

Leveraging cognitive resources to investigate the impact of molecular orientation on students’ activation of symmetry resources

This study investigates students’ cognitive resources for identifying symmetry elements using survey data collected from 39 inorganic chemistry students from twelve undergraduate inorganic classes at universities across the United States. We propose a framework that leverages students’ knowledge of symmetry elements as a manifold of cognitive resources that can be productive or unproductive in certain contexts. This cognitive resources framework was paired with an asset-based perspective to advance work in this area beyond a deficit-framed study of “correctness”. Herein, we present findings from a qualitative analysis of the rotation and reflection symmetry elements activated for students by four select molecules. Each molecule was presented in two different static orientations to determine the impact of orientation on students’ cognitive resource activation. Our findings suggest that the orientation of static molecular images impacts the types of resources activated for students. Additionally, this study serves as an example for how to advance assessment of this topic beyond a binary approach (i.e. correct or incorrect).

Experimental investigation of flow past three-cylinder rotating system

Wake interactions from a three-cylinder system arranged in an intermediate-spacing setting in static and rotating conditions are investigated. The complex flows generated are relevant to fundamental fluid flow phenomena and engineering applications and merit investigation. In this study, experiments using hot-wire and two-dimensional (2D) Particle Image Velocimetry (PIV) are conducted in order to characterize the fluid flow at various Reynolds numbers and rotational speeds. The three-cylinder system setup is in equidistant triangular arrangement, each cylinder having diameter of 3.1 mm with a 9.7 mm circumscribed-circle diameter among them. To elucidate the cylinder system flow phenomena occurring during static and rotating conditions, the PIV measurement campaign was conducted in two stages. Firstly, a very close view of the flow was used to capture wake interaction between three cylinders in detail at a representative case of low Reynolds number, Re = 57, at three static orientations. Secondly, the experiment was conducted using a larger field of view to capture far field flow characteristics at increased Reynolds numbers, Re = 310 and 1250, for three static orientations and various rotating conditions. For static cases, the results show some flow phenomena that has been reported in several computational studies before, but new experimental evidence of early mixing and breakdown of the wake through a variety of flow patterns are revealed. With the addition of the new parameter of continuous rotation, the three-cylinder system further evolves into new scenarios, including cases with resembling single-cylinder wake patterns. Time-resolved characteristics of the flow are obtained from point-wise hot-wire anemometry and are presented as a function of cylinder system rotational speed, Re number, and non-dimensional frequency or Strouhal (St) number.

The motion silencing effect in static and dynamic orientation change detection

The motion silencing effect in static and dynamic orientation change detection

Tensile performance and viscoelastic properties of rubber nanocomposites filled with silica nanoparticles: A molecular dynamics simulation study

Understanding the relationship between the macro-properties and microstructure of rubber and rubber nanocomposites (RNCs) is crucial for the design and optimization of relevant rubber composite products. Herein, we explore the mechanical and viscoelastic properties of rubber and RNCs filled with silica nanoparticles by using atomistic molecular dynamics simulation. It is found that increasing cross-linking density can greatly enhance the tensile performance of pure rubber, and reduce the permanent deformation and hysteresis loss. The addition of silica nanoparticles causes significant changes in the static distribution, movement, and bond orientation, and the Tg of RNCs increases by more than 6% when the volume fraction of NPs reaches 10%. At fixed volume fraction of NPs, decreasing the NP size can further enhance the mechanical properties of RNCs, and the maximum tensile stress can increase by 50%. In addition, cross-linking in the RNCs can improve the viscoelastic properties, and more highly crosslinked RNCs present larger storage modulus and loss modulus, and smaller loss angle. This work gives an in-depth understanding of the effect of microstructure on the mechanical properties of RNCs.

A quaternion-based sensor fusion approach using orthogonal observations from 9D inertial and magnetic information

The micro-electro-mechanical technology facilitates the development of low-cost orientation estimation solutions using inertial and magnetic sensors. However, the magnetic disturbances challenge the robust pitch and roll measurements on some occasions, such as the quadrotor, ship, and railway. This work analyzes the coupling mechanism of the magnetic information on the roll and pitch estimates. Subsequently, it proposes a quaternion-based decoupled sensor fusion approach under the frame of an extended Kalman filter by taking the orthogonal gravitational vector and horizontal magnetic vector as absolute observation references. Three experimental tests validated its performances in robust roll and pitch measurements under magnetic disturbances, static and dynamic robotic motion estimation, and human upper body pose tracking. Results show that the proposed sensor fusion approach could keep the roll and pitch immune to the magnetic disturbances, and provide reliable static and dynamic orientation estimation accuracy. Moreover, it is promising to provide feedback for rehabilitation training.

Long-duration head down bed rest as an analog of microgravity: Effects on the static perception of upright

BACKGROUND:Humans demonstrate many physiological changes in microgravity for which long-duration head down bed rest (HDBR) is a reliable analog. However, information on how HDBR affects sensory processing is lacking.OBJECTIVE:We previously showed [25] that microgravity alters the weighting applied to visual cues in determining the perceptual upright (PU), an effect that lasts long after return. Does long-duration HDBR have comparable effects?METHODS:We assessed static spatial orientation using the luminous line test (subjective visual vertical, SVV) and the oriented character recognition test (PU) before, during and after 21 days of 6° HDBR in 10 participants. Methods were essentially identical as previously used in orbit [25].RESULTS:Overall, HDBR had no effect on the reliance on visual relative to body cues in determining the PU. However, when considering the three critical time points (pre-bed rest, end of bed rest, and 14 days post-bed rest) there was a significant decrease in reliance on visual relative to body cues, as found in microgravity. The ratio had an average time constant of 7.28 days and returned to pre-bed-rest levels within 14 days. The SVV was unaffected.CONCLUSIONS:We conclude that bed rest can be a useful analog for the study of the perception of static self-orientation during long-term exposure to microgravity. More detailed work on the precise time course of our effects is needed in both bed rest and microgravity conditions.

The effect of inter-particle hydrodynamic and magnetic interactions in a magnetorheological fluid

A magnetorheological fluid, which consists of magnetic particles suspended in a viscous fluid, flows freely with well-dispersed particles in the absence of a magnetic field, but particle aggregation results in flow cessation when a field is applied. The mechanism of dynamical arrest is examined by analysing interactions between magnetic particles in a magnetic field subject to a shear flow. An isolated spherical magnetic particle undergoes a transition between a rotating state at low magnetic field and a static orientation at high magnetic field. The effect of interactions for spherical dipolar and polarisable particles with static orientation is examined for an unbounded dilute viscous suspension. There are magnetic interactions due to the magnetic field disturbance at one particle caused by the dipole moment of another, hydrodynamic interactions due to the antisymmetric force moment of a non-rotating particle in a shear flow, and a modification of the magnetic field due to the particle magnetic moment density. When there is a concentration variation, the torque balance condition results in a disturbance to the orientation of the particle magnetic moment. The net force and the drift velocity due to these disturbances is calculated, and the collective motion generated is equivalent to an anisotropic diffusion process. When the magnetic field is in the flow plane, the diffusion coefficients in the two directions perpendicular to the field direction are negative, implying that concentration fluctuations are unstable in these directions. This instability could initiate field-induced dynamical arrest in a magnetorheological fluid.

Minimally invasive temporalis tendon transposition and upper lid lipofilling for immediate and secondary facial reanimation in patients treated for malignant tumors of the parotid gland

Treatment for facial nerve-invading parotid malignancies usually results in complete facial palsy. The authors present a novel technique to treat facial palsy following radical parotid surgery and retrospectively evaluate results in terms of soft tissue symmetry at rest and during smiling and eyelid closure using the eFACE system.9 patients with facial palsy following parotid malignancies resection or undergoing parotidectomy with planned facial nerve resection for tumor invasion were treated with the association of mini-invasive temporalis flap rotation and upper lid lipofilling to restore symmetry of the middle facial third at rest and during smiling and eyelid closure. The technique was employed during the same surgical session as the tumor removal or for secondary facial reanimation.Systematic eFACE evaluation demonstrated significant improvement in static nasolabial fold depth orientation and oral commissure position, palpebral fissure narrowing during eye closure, and oral commissure movement and nasolabial fold depth and orientation with smile (p respectively .008, .011, 0.008, 0.035, 0.011, 0.008, and 0.011, Wilcoxon's test). Furthermore, all patients described subjective improvement of corneal discomfort.The presented technique appears promising in treating facial palsy in oncological patients, representing a potential alternative to other more complex reconstructive techniques.

Comparison of non-coplanar optimization of static beams and arc trajectories for intensity-modulated treatments of meningioma cases

Two methods for non-coplanar beam direction optimization, one for static beams and another for arc trajectories, were proposed for intracranial tumours. The results of the beam angle optimizations were compared with the beam directions used in the clinical plans. Ten meningioma cases already treated were selected for this retrospective planning study. Algorithms for non-coplanar beam angle optimization (BAO) and arc trajectory optimization (ATO) were used to generate the corresponding plans. A plan quality score, calculated by a graphical method for plan assessment and comparison, was used to guide the beam angle optimization process. For each patient, the clinical plans (CLIN), created with the static beam orientations used for treatment, and coplanar VMAT approximated plans (VMAT) were also generated. To make fair plan comparisons, all plan optimizations were performed in an automated multicriteria calculation engine and the dosimetric plan quality was assessed. BAO and ATO plans presented, on average, moderate global plan score improvements over VMAT and CLIN plans. Nevertheless, while BAO and CLIN plans assured a more efficient OARs sparing, the ATO and VMAT plans presented a higher coverage and conformity of the PTV. Globally, all plans presented high-quality dose distributions. No statistically significant quality differences were found, on average, between BAO, ATO and CLIN plans. However, automated plan solution optimizations (BAO or ATO) may improve plan generation efficiency and standardization. In some individual patients, plan quality improvements were achieved with ATO plans, demonstrating the possible benefits of this automated optimized delivery technique.

Design and Build a Sun Tracking System Using a Fuzzy Logic Controller to Optimize the Output Power of the Solar Cell Module

The solar cell module is an electric device that can convert sunlight energy to electric energy directly. Some matters cause solar cell module produceselectric energy unoptimally. One of the problem is position of solar cell module is not vertically coming through the sunlight. This problem is caused by daily earth rotation and yearly earth surrounding the sun. Major Topics of this research are producing a fuzzy logic controlling system so that orientation of solar cell module always follows position of sun periodically. And then comparing power of solar cell module which using controlling system to power of solar cell module which in static orientation. Result of this research, controlling system using fuzzy logic controller is produced, for controlling orientation of solar cell module follows sun position, with error about 4.270, so that power of this solar cell module is higher 10.8% than power of static solar cell module. Average power of static solar cell module is about 2,957 watts, and the energy is about 23,656 watt hour. Else power of dynamic solar cell module is about 3,276 watts, and the energy is about 26,208 watt hour.

Empirical and simulated evaluations of easy-axis dynamics of magnetic nanoparticles based on their magnetization response in alternating magnetic field

Physical rotation of the easy axes of magnetic nanoparticles significantly affects their magnetization properties in fluid, which are important for biomedical applications. The rotation and alignment of the easy axis toward a specific direction in an alternating magnetic field are affected by fluid conditions such as viscosity, the condition of the applied magnetic field, and the magnetic properties of the nanoparticles, including anisotropy. In this study, we experimentally evaluated the physical rotation and alignment of the easy axes of nanoparticles in a viscous medium by preparing samples in which the orientation of the easy axis was fixed in an alternating field at each frequency across a wide frequency range. The numerical simulation with respect to the transitional and steady-state easy-axis dynamics determined by Néel and Brownian relaxation sufficiently supported the empirically observed phenomena. The factors dominating the easy-axis dynamics with rotation and static orientation in an alternating magnetic field, such as the Brownian relaxation time, magnetic torque, and applied field frequency, were clarified. The alignment degree, including its direction and rotation amplitude, was found to depend on the viscosity of the medium associated with the Brownian regime and the magnetic torque derived from the Néel regime. Nonlinear magnetization appeared as the harmonic components of the magnetization in a viscous medium were strongly influenced by the static alignment of the easy axis.

Modulation of the solution-cathode glow-discharge and solution-anode glow discharge using a rotating magnetic field

The effects of an external magnetic field on the solution-cathode glow-discharge (SCGD) and solution-anode glow-discharge (SAGD) are investigated. The SCGD is atmospheric-pressure glow discharge sustained between a metal pin and a liquid cathode electrode in the ambient atmosphere, and it is often used for trace elemental analysis by atomic emission spectroscopy. Here, the SCGD is modified to allow an external permanent magnetic field to be applied, either in a static orientation or as a rotating field, as a means of stabilizing the SCGD plasma and modulating atomic emission from the discharge. The effect of the external magnetic field on the physical structure, electrical characteristics, and spectroscopic response of the SCGD and SAGD are investigated. A rotating external magnetic field was found to change both SAGD and SCGD structure and spatial emission pattern. Analytical figures of merit are examined, and a lock-in amplifier is used to discriminate analytical atomic emission from background emission, improving limits of detection.

Dynamically induced friction reduction in micro-structured interfaces

We investigate the dynamic behavior of a regular array of in-plane elastic supports interposed between a sliding rigid body and a rigid substrate. Each support is modelled as a mass connected to a fixed pivot by means of radial and tangential elastic elements. Frictional interactions are considered at the interface between the supports and the sliding body. Depending on the specific elastic properties of the supports, different dynamic regimes can be achieved, which, in turn, affect the system frictional behavior. Specifically, due to transverse microscopic vibration of the supports, a lower friction force opposing the macroscopic motion of the rigid body can be achieved compared to the case where no supports are present and rubbing occurs with the substrate. Furthermore, we found that the supports static orientation plays a key role in determining the frictional interactions, thus offering the chance to specifically design the array aiming at controlling the resulting interfacial friction force.