Rotation Research Articles

Imperfect O(2) symmetry in counter-rotating split-cylinder flow

The effect of a small imperfection in the counter-rotating split-cylinder flow is studied numerically. The defect is characterized by a small parameter ϵ, corresponding to the difference in the magnitude of rotations in each half of the cylinder. With the two half cylinders not rotating exactly in counter rotation, the O(2) symmetry of the exact counter-rotating case (invariance to azimuthal rotations as well as to an involution consisting of reflections about the mid-plane composed of reflections about any meridional plane) is weakly broken. This small defect results in relevant variations in the flow. For slow rotations (characterized by a small Reynolds number), the system remains axisymmetric with the imperfection only breaking the reflection symmetry about the cylinder half-height. At larger Reynolds numbers, in the absence of the imperfection, axisymmetry is broken resulting in steady states with azimuthal wavenumber m. When axisymmetry is broken in the presence of the imperfection, a background rotation is introduced. Depending on the case and the level of imperfection, either rotating waves or slow-fast dynamics with mean background rotations are found instead. The interaction between azimuthal wavenumbers m = 2 and 3 plays a crucial role in the flow. The flow is analyzed in detail, varying ϵ from a very small value of 0.01%, typical of a natural imperfection in an experimental setup, to higher values corresponding to forced symmetry breaking. The ramifications of the imperfection on various solution states found in the exact counter-rotating case for a fixed aspect ratio are investigated.

Impacts of Rice Field Winter Planting on Soil Organic Carbon and Carbon Management Index

To tackle with the problem of prevailing farmland abandonment in winter, 5 treatments includes Chinese milk vetch-double cropping rice (CRR), rape-double cropping rice (RRR), garlic-double cropping rice (GRR), winter crop multiple cropping rotation (ROT), winter fallow control (WRR) were set up. By measuring soil total organic carbon, active organic carbon and its components and calculating the soil carbon pool management index in 0~15 cm and 15~30 cm soil layers in the early and late rice ripening stage. The effects of different winter planting patterns on the changes of soil organic carbon and carbon pool management index were discussed. In order to provide theoretical basis for the optimization and adjustment of winter planting pattern of double cropping rice field in the middle reaches of Yangtze River. The results showed that soil total organic carbon, active organic carbon and its components in different winter cropping patterns were increased, and ROT and CRR treatments were more beneficial to the accumulation of soil total organic carbon, active organic carbon and its components as well as the improvement of soil carbon pool management index, which should be preferred in the adjustment of cropping patterns.

Characteristics of elite cricket fast bowlers who do and do not sustain a lumbar bone stress injury: Multifactorial analysis over 4 years

Introduction: Lumbar bone stress injuries (LBSI) are the highest time-loss injury among cricket fast bowlers. Previous studies have identified risk factors such as shoulder counter rotation and lateral flexion during bowling delivery, lumbar extension endurance on screening, and high bowling loads. However, findings tend to be unidimensional, inconsistent, and limited to a short time-frame. The purpose of this study was to address these limitations by retrospectively reviewing 4-seasons of data across multiple domains. Methods: Data of elite male fast bowlers was retrieved from Cricket Australia’s Athlete Management System for the seasons 2016-17 to 2019-20. Bowlers who sustained a LBSI during a season, denoted “injured” (n=32, 22.8 ± 4.3 years) were compared to bowlers who did not sustain a LBSI in the previous 5 years, denoted “non-injured” (n=18, 25.8 ± 4.2 years). Bowling biomechanics, musculoskeletal screening, fitness tests, and bowling loads were compared between injured and non-injured bowlers using univariate and multivariate analyses. Results: Injured bowlers were younger than non-injured (p=0.026). Injured and non-injured bowlers had similar biomechanics, with the exception of a possible larger amount of lumbar extension at front foot contact (FFC) (d = 0.6) and a straighter front knee at FFC (d = 0.5) in the injured group. There was no difference in musculoskeletal screening and fitness tests between groups. Injured and non-injured bowlers had similar bowling loads over the 4 weeks preceding injury (or equivalent time-point for non-injured group). Non-injured bowlers bowled more balls over 12 weeks (1499, p=0.007) and more balls (5137, p=0.001) and more days over 1 year (113, p=0.012). Discussion: This study adds to the existing literature, supporting younger age as a risk factor for LBSI. Bowling biomechanics and bowling loads evidently contribute to LBSI risk, however there is not a clear delineation for increased risk. These findings emphasise the complexity of LBSI in elite male fast bowlers. An individualised and adaptive approach to managing the preparation of fast bowlers is recommended. Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

Effect of rotation in the γ -ray emission from 60 meV polarized neutron-induced fission of the U235 isotope

In the paper we present the results obtained for the effect of rotation (ROT) in the angular distribution of prompt $\ensuremath{\gamma}$ rays from the fission of $^{235}\mathrm{U}$ induced by monochromatic polarized ``warm'' neutrons (${E}_{n}$ = 60 meV). The polarization vector direction is determined at the target position in order to correctly determine the sign of the measured effect. The asymmetry parameter was found to be equal to ${R}_{\ensuremath{\gamma}}=\ensuremath{-}(17.3\ifmmode\pm\else\textpm\fi{}2.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. Moreover, the rotation angle of the fission axis was determined to be equal to $0.{069}^{\ensuremath{\circ}}\ifmmode\pm\else\textpm\fi{}0.{008}^{\ensuremath{\circ}}$ taking into account the fit results of the angular distribution of the prompt fission $\ensuremath{\gamma}$ rays. The obtained value and sign of the ROT effect are consistent with the results of the ROT effect obtained for cold neutrons. We describe the experiment, methodology of sign determination, and implications of the results.

Normative Reference Values for Trunk Range of Motion and Isometric Muscle Strength in Asymptomatic Young Indian Adults.

To determine normative reference values for trunk range of motion (ROM) and isometric strength (TIS) in asymptomatic young, Indian adults. Age, gender, body mass index, lifestyle, and dynamometer-based device measurements of trunk ROM and TIS in extension (EXT), flexion (FLX), and rotation (ROT) were recorded and analysed in 80 asymptomatic subjects between 20 and 40years of age. Correlation analysis was performed to determine factors influencing EXT and FLX ROM and TIS. The normative reference values for mean trunk EXT, FLX, right ROT, and left ROT ROM were 23° (95th percentile 31.9°), 40.2°(95th percentile 51.5°), 36.8°(95th percentile 57.7°), and 35.4° (95th percentile 55.7°), respectively; and for mean EXT, FLX, right ROT, and left ROT TIS were 118.1 Nm (95th percentile 278.8 Nm), 63.8 Nm (95th percentile 159.4 Nm), 39.9 Nm (95th percentile 113.6 Nm), and 42.8 Nm (95th percentile 108.9 Nm), respectively. The mean EXT (p = 0.0002), right (p = 0.02), and left ROT ROM (p = 0.01), and the mean EXT, FLX, and ROT TIS (p < 0.0001) were significantly greater in males compared to females. The FLX, EXT, and ROT TIS showed significant strong correlation with EXT and FLX TIS. Mean TIS values in Indian subjects were lower when compared to subjects from other countries. This study established normative reference values for trunk ROM and TIS in asymptomatic young Indian adults. These reference values can be helpful to diagnose trunk ROM and TIS deficits, identify subjects at risk for LBP and disability, and individualise rehabilitation treatment in them.

Influence of counter rotation on fluid flow and heat transfer around tandem circular cylinders at low Reynolds number

Influence of counter rotation on fluid flow and heat transfer around tandem circular cylinders at low Reynolds number

Soil Water Retention and Soil Compaction Assessment in a Regional-Scale Strategy to Improve Climate Change Adaptation of Agriculture in Navarre, Spain

The aim of this study was to evaluate the effectiveness of the different agricultural management adaptive strategies considered in the framework of a regional climate change adaptation roadmap in Navarre (Spain), from the point of view of soil physical indicators associated to soil compaction and water retention. These indicators were chosen as representative of the potential of these strategies to improve the soil physical condition. That for, the effectiveness of conservation agriculture (CA), crop rotations (ROT), additions of organic matter (ExO), irrigation (IRR) and innovative grassland management (GSS) was assessed by monitoring soil bulk density (BD) and soil available water holding capacity (AWHC) in a network of 159 agricultural fields across homogeneous agro-climatic zones in the region. A sampling protocol designed to compare groups of plots with or without adaptive practices, and with equal soil characteristics within each zone, allowed to determine the effect size of each strategy (measured as response ratios, RR, calculated as the relative value of BD and AWHC in fields with adaptive management vs. without). Both parameters responded to soil and crop management, although the observed effect was highly variable. Only the ExO strategy showed an overall positive effect on BD. ROT, IRR and GSS displayed no effect and, in the case of CA, the effect was negative. In terms of AWHC, although the results within the zones were heterogeneous, the overall effect associated to the strategies ROT, ExO, IRR and GSS was neutral, and only CA resulted in an overall negative effect. The observed variability in terms of the effectiveness of the five strategies tested in this region highlights the need to understand the complexity of interrelationships between management and dynamic soil properties at the regional scale.

Design of a horizontal-dual bladed bioreactor for low shear stress to improve hydrodynamic responses in cell cultures: A pilot study in Chlamydomonas reinhardtii

The aim of this study is to investigate the potential of a novel design considering low shear horizontal bioreactor (LSB-R) with counter rotation U-shape impellers. Bioreactors (LSB-R and STR) were compared under the same mixing time (23 ± 2 s) using Computational Fluid Dynamics analysis focusing on the shear stresses. The highest shear stress was around the impeller tips with an average shear stress found to reach up to 0.8 Pa for LSB-R a very small value compared to the 100-fold increase inside the STR. Cell wall deficient and motility impaired mutants of Chlamydomonas were used in the experiments to see the effects of shear stress on growth and morphology. Biomass productivities were almost doubled, and specific growth rates were increased by LSB-R. On the other hand, the motility impaired cells aligned as colonies to protect from shear forces in STR and a rapid death occurred in cells with flagella due to continuous deflagellation and cell damage. The results indicate that; LSB-R design has great advantage on lowering shear stress, eliminating excessive hydrodynamic forces, providing mild operation conditions.

DOES VISUAL-SPATIAL COGNITION AFFECT CHILDREN’S ASTRONOMICAL EXPERIENCES?

Understanding of astronomical phenomena requires spatial reasoning skills. The current study examines the influence of spatial ability on conceptual understanding of secondary school students in elementary astronomy. The sample consisted of 38 ninth-grade students from a high school in Hyderabad. To evaluate participants’ spatial ability, spatial reasoning test, Purdue Spatial Visualization Test: Visualization of Rotations and mental rotation tests were used. Mental Rotation, Spatial Perception, and Spatial Visualization are the types of spatial ability tested in this study. To understand learners conceptual understanding in astronomy, 30 probes on astronomical topics were administered. The research study was quantitative in nature. Correlational analysis showed that all three spatial sub-skills namely Spatial Orientation, Mental rotation and Spatial Visualization is associated with astronomy conceptual understanding. The correlation coefficient of overall spatial ability and conceptual understanding was 0.693 (p Article visualizations:

Seismic response of utility tunnels subjected to different earthquake excitations

The influence of ground motions on the seismic response of utility tunnels was investigated. A series of small-scale shaking table model tests were carried out under uniform excitation in the transverse direction. Different peak accelerations of EL-Centro and Taft earthquake waves were applied. The acceleration responses, earth pressure, seismic strain, bending moment and structure deformations were measured and discussed. The results showed that the types of earthquake waves had significant influences on the soil-structure acceleration responses. However, the amplitude of the soil acceleration along the depth showed consistent variation regardless of the types of earthquake waves and tunnels. The horizontal soil pressure near the top and bottom slabs showed obviously larger values than those at other depths. In general, the strain response in the outer surface was more significant than that on the inner surface, and the peak strain in the end section of the model was larger than that in the middle section. Moreover, the bending moment at the corner points was much larger than that at middle point, and the bending moment was greatly affected by both input accelerations and seismic wave types. The opposite direction of shear deformation on the top and bottom slabs presented a rotation trend of the model structure.

Study on lateral behavior of digging well foundation with consideration of soil-foundation interaction

Digging well foundation has been widely used in railway bridges due to its good economy and reliability. In other instances, bridges with digging well foundation still have damage risks during earthquakes. However, there is still a lack of knowledge of lateral behavior of digging well foundation considering the soil-foundation interaction. In this study, scaled models of bridge pier-digging well foundation system are constructed for quasi-static test to investigate their lateral behaviors. The failure mechanism and responses of the soil-foundation-pier interaction system are analyzed. The testing results indicate that the digging foundations tend to rotate as a rigid body under cyclic lateral load. Moreover, the depth-width ratio of digging well foundation has a significant influence on the failure mode of the interaction system, especially on the distribution of foundation displacement and the failure of pier. The energy dissipation capacity of the interaction system is discussed by using index of the equivalent viscous damping ratio. The damping varies with the depth-width ratio changing. The equivalent stiffness of soil-digging well foundation-pier interaction system decreases with the increase of loading displacement in a nonlinear manner. The absolute values of the interaction system stiffness are significantly influenced by the depth-width ratio of the foundation.

Time and Reversal in Birtwistle's Punch and Judy

We examine the occurrence of peripeteia in Harrison Birtwistle's 1967 opera Punch and Judy, as manifest in a reversal of cyclic time. Specifically, we extend a metaphorical association between the passage of cyclic time in the opera and discrete rotation in the complex plane generated by the imaginary unit i. Such a rotation moves alternately between the real and the imaginary axes, as scenes in the opera pass correspondingly through sacred and profane orientations. The instance of peripeteia results in a counter rotation, a dramaturgical inversion. To bring this reversal into the metaphor, we extend it from its situation in the complex plane to one in the space of Hamilton's quaternions, wherein such negation is obtained through the product of upper-level imaginary units. The scene that contains the reversal and that which consists of the opera's comic resolution epitomize the drama and occupy the highest level of dramatic structure.

The Differences of Audit Quality on the Regulation of Audit Tenure and Auditor Rotation in Indonesia

This study examines the differences in audit quality on the regulation of audit tenure and auditor rotation in Indonesia. In Indonesia, there have been several audit-related scandals that occurred after the implementation of regulations on the audit tenure limitation and auditor rotation. The last regulation that applies to date is the Peraturan Pemerintah Republik Indonesia No. 20/2015 about Public Accountant Practices Chapter V regarding the Limitation of Audit Services in Article 11 that the provision of audit services on a historical financial statement on an entity by a Public Accountant is limited to a maximum of five consecutive financial years. These analyses use discretionary accruals as audit-quality proxies. In this study, the output of audit quality is measured, namely the earnings quality. This research was conducted on all non-financial companies listed on the Indonesia Stock Exchange start from 2012 to 2017, using the purposive sampling method obtained 554 research samples. Hypothesis analyses in this study use different test analysis. Specifically, there is a significant difference in the audit quality in the first year of the tenure and the last year of the tenure. We also find significant differences in audit quality before and after auditor rotation.

The Bureaucratic Political Relation Model in Perception of Officers Public: a Study on Bima City Government

The relationship between politics and bureaucracy is significant to observe because this concerns the interests of policymakers and stakeholders related to the politics of local government policies. In this regard, this study aims to describe the Political Relations Model Bureaucracy in the Perception of Public Officials (A Study at the Bima City Government). The approach in this research is descriptive qualitative. The results showed that the Relationship Model Bureaucratic Politics in the Perception of Public Officials (A Study at the Bima City Government) have interrelated and mutually supportive relationships both in formulating, implement and evaluate policies both political and administration towards the implementation of the public bureaucracy in the Bima City Government. Perception public officials concerning political intervention in carrying out activities bureaucracy are reflected in the process of development, administration, and technique as well as transfer and high employee rotation, institutional restructuring of the Bima City government bureaucracy as well The formulation of the Kota Bima Regional Financial Budgeting always occurs for political intervention interests of both public officials and career officials in running the wheel the government in the city of Bima.

Isogeometric Collocation Method to solve the strong form equation of UI-RM Plate Theory

This work presents the formulation of the isogeometric collocation method to solve the strong form equation of a unified and integrated approach of Reissner Mindlin plate theory (UI-RM). In this plate theory model, the total displacement is expressed in terms of bending and shear displacements. Rotations, curvatures, and shear strains are represented as the first, the second, and the third derivatives of the bending displacement, respectively. The proposed formulation is free from shear locking in the Kirchhoff limit and is equally applicable to thin and thick plates. The displacement field is approximated using the B-splines functions, and the strong form equation of the fourth-order is solved using the collocation approach. The convergence properties and accuracy are demonstrated with square plate problems of thin and thick plates with different boundary conditions. Two approaches are used for convergence tests, e.g., increasing the polynomial degree (NELT = 1✕1 with p = 4, 5, 6, 7) and increasing the number of element (NELT = 1✕1, 2✕2, 3✕3, 4✕4 with p = 4) with the number of control variable (NCV) is used as a comparable equivalent variable. Compared with DKMQ element of a 64✕64 mesh as the reference for all L/h, the problem analysis with isogeometric collocation on UI-RM plate theory exhibits satisfying results.

Focal and pseudo/rotational activations in human atrial fibrillation defined with automated periodicity mapping.

Defining atrial fibrillation (AF) wave propagation is challenging unless local signal features are discrete or periodic. Periodic focal or rotational activity may identify AF drivers. Our objective was to characterize AF propagation at sites with periodic activation to evaluate the prevalence and relationship between focal and rotational activation. We included 80 patients (61 ± 10 years, persistent AF 49%) from the FaST randomized trial that compared the efficacy of adjunctive focal site ablation versus pulmonary vein isolation. Patients underwent left atrial (LA) activation mapping with a 20-pole circular catheter during spontaneous or induced AF. Five-second bipolar and unipolar electrograms in AF were analyzed. Periodic sites were identified by spectral analysis of the bipolar electrogram. Activation maps of periodic sites were constructed using an automated, validated tracking algorithm, and classified into three patterns: focal sites (FS), rotation (RO), or pseudo-rotation (pRO). The most common propagation pattern at periodic sites was FS for 5-s in all patients (4.9 ± 1.9 per patient). RO and pRO were observed in two and seven patients, respectively, but were all transient (3-5 cycles). Activation from a FS evolved into transient RO/pRO in five patients. No patient had autonomous RO/pRO activations. Patients with RO/pRO had greater LA surface area with periodicity (78 ± 7 vs. 63 ± 16%, p = .0002) and shorter LA periodicity CL (166 ± 10 vs. 190±28 ms, p = .0001) than the rest. Using automated, regional AF periodicity mapping, FS is more prevalent and temporally stable than RO/pRO. Most RO/pRO evolve from neighboring FS. These findings and their implications for AF maintenance require verification with global, panoramic mapping.

Maxwell Equations Derived from Coulomb’ Law vs. Maxwell-type Gravity Derived from Newton’s Law

A Universal Mathematical Field Theory (UMFT) is established and states that the combination of the operations of both gradient and divergence of vector fields, such as electric field and velocity field, create the curl of an axial vector field, such as magnetic field. Utilizing UMFT, Extended-Maxwell equations and the equation of Lorentz force are derived from the combination of Coulomb’s law and velocity of source mathematically, and new effects are predicted. For a source moving with non-spatially-varying velocity Extended-Maxwell equations reduce to Maxwell equations. This derivation mathematically explains how a moving electric charge creates magnetic field, and shows that there is no magnetic monopole charge. The duality between the Newton’s law and the Coulomb’s law leads us to derive Maxwell-type gravitational equations and Lorentz-type gravitational force by combining UMFT, the Newton’s law and velocity of gravitational source, denoted as Gravito-electromagnetic, which is dual of Electromagnetics. The benefits of the duality are that the effects and phenomena of Electromagnetics may be directly converted to that of gravity. The Gravito-Electromagnetics are employed to study the accelerating expansion of the universe, rotation curve, virial theorem, and gravitation radiation.

Initial Student Perspective on Plastic Surgery Virtual Away Rotations.

The COVID-19 pandemic’s social distancing efforts have created unprecedented challenges in medical education. A unique challenge falls on medical students and residency programs as they prepare for the 2020 to 2021 residency application cycle. In May of 2020, the American Council of Academic Plastic Surgeons released a statement strongly recommending the cancellation of traditional in-person away rotations for students who have a home plastic surgery residency program and hosting all residency interviews virtually for the 2020 to 2021 cycle.1 This news may be particularly distressing for plastic surgery applicants, where completing away rotations has been shown to be critical for applicants and program directors alike.2,3 Many applicants may feel that they have lost the opportunity to express interest in a program, identify how well they would fit at an outside institution, and obtain letters of recommendations. Indeed, interacting with residents and faculty has been shown to be the primary motivating factor for completing away rotations.2,3 Similarly, residency programs may feel less able to share the unique characteristics of their program and evaluate interest from potential applicants. Furthermore, widespread cancellation of in-person clinical rotations because of COVID-19 has resulted in much uncertainty for medical students regardless of specialty interest.4 Despite the particular challenges posed during this time, it has sparked creative solutions and is a potential opportunity to improve the equity of the plastic surgery match process.5 Many programs now organize virtual meetings to introduce their program to interested students. These events are well received as cost-effective and logistically feasible options for students to interact with programs. However, the experience and value provided by a subinternship should not be discounted. The University of California, San Diego, Division of Plastic Surgery recently initiated one of the first virtual away rotation opportunities. Through this 2-week virtual rotation, students can participate in a more immersive experience, ranging from case discussions, mentorship meetings, and informal social events with residents. As some of the first students to participate in a virtual away rotation, we have gained a much stronger understanding of the residency program. Compared to the virtual webinars or open-house conferences that host numerous students, virtual subinternships allow for more in-depth learning experiences and intimate relationship-building opportunities. Although these may not entirely replace the experience of in-person visiting subinternships, the University of California, San Diego, virtual rotation allowed us to further our knowledge of plastic surgery and get to know the University of California, San Diego, plastic surgery residency program’s culture. In addition, virtual rotations can help mitigate the uncertainty associated with COVID-19 rotation cancellations by providing clinically based curricular activities with specific learning objectives. We encourage other programs to consider developing virtual away rotations so that more students have the opportunity to demonstrate interest in and better understand specific residency programs. In conclusion, virtual away rotations are an innovative method of engaging students and residency programs during the COVID-19 pandemic. As more residency programs develop virtual opportunities for medical students, we hope that this will make the plastic surgery application process more equitable for prospective applicants. DISCLOSURE The authors have no financial interest to declare in relation to the content of in this article.

Measurement and Treatment of Abnormalities of Medial and Lateral Rotation of Upper Limb in Shoulder

Measurement and Treatment of Abnormalities of Medial and Lateral Rotation of Upper Limb in Shoulder

Geometrical design of variable ratio tooth profile based on Boolean subtraction operation and a novel modification method

Variable transmission ratio racks show great potential in rice transplanters as a key component of variable transmission ratio steering to balance steering portability and sensitivity. The objective of this study was to develop a novel geometrical design method to achieve quick, high-quality modeling of the free curvilinear tooth profile of a variable transmission ratio rack. First, a discrete envelope motion 3D model was established between the pinion-sector and the variable transmission ratio rack blank based on the mapping relationship between the rotation angle of the pinion-sector and the displacement of the rack, according to the variable transmission ratio function. Based on the loop Boolean subtraction operation, which removed the pinion-sector from the rack blank during all moments of the discrete motion process, the final complex changing tooth shape of the variable transmission ratio rack was enveloped. Then, since Boolean cutting residues made the variable ratio tooth surface fluctuant and eventually affected the precision of the model, this study proposed a modification method for establishing a smooth and continuous tooth profile. First, a novel fitting algorithm used approximate variable ratio tooth profile points extracted from the Boolean cutting marks and generated a series of variable ratio tooth profiles by utilizing B-spline with different orders. Next, based on a transmission stability simulation, the variable ratio tooth profile with optimal dynamic performance was selected as the final design. Finally, tests contrasting the transmission stability of the machining samples of the initial variable ratio tooth profile and the final variable ratio tooth profile were conducted. The results indicated that the final variable ratio tooth profile is more effective than the initial variable ratio tooth profile. Therefore, the proposed variable ratio tooth profile modeling and modification method for eliminating Boolean cutting residues and improving surface accuracy is proved to be feasible. Keywords: rice transplanter, steering, variable ratio tooth profile, variable ratio curve, Boolean subtraction operation, transmission stability DOI: 10.25165/j.ijabe.20201305.4884 Citation: Niu Z R, Li J L, Xin S, Zou L L, Li Y H, Hou J L, et al. Geometrical design of variable ratio tooth profile based on Boolean subtraction operation and a novel modification method. Int J Agric & Biol Eng, 2020; 13(5): 125–133.