Back Bending Research Articles

Study Shapes and Alignments of Rotational States in Some Rare-Earth Nuclei

The ground state rotational band members for the studied nuclei have been identified and their energies calculated to about 0.3%. These energies provide good test of various models for rotational bands, and impressive agreement is observed with a theoretical calculations by the variable moment of inertia (VMI) model and cubic polynomial (CP) formula. In addition to giving an excellent fit to the excitation energy of the ground-band levels in all nuclei. Also reproduces a critical spin Ic beyond which the square rotational frequency ω2 decreases although the moment of inertia ℑ keeps on increasing, thus resulting in back bending in I -ω2 plot for some of the studied nuclei. This feature is predicted to appear not only in the deformed nuclei but also at quite low spins in nearly spherical nuclei as well. Also the formula contains the low and high spin behavior in agreement with the available experimental data.

3A1-S04 複合弾性材S-FRPを用いた軽労化スーツ(ウェアラブルロボティクス)

This paper describes an innovative passive element for assistive device and its application. S-FRP is an elastic composite consisting of FRP and rubber. S-FRP provides restoring force in 3 dimension. A prototype of S-FRP and its basic characteristics are shown. Moreover, a prototype of KEIROKA-assistive suit using S-FRP for supporting back bend motion is developed. The authors show experimental results that the prototype suit can reduce 20% of muscular activations in back bending and stretching motions.

The soldier and the scientist

To an average soldier the very name of a scientist conjures up strange visions of grey haired old gentleman who spend their lives in back cellars bending over flasks and tubes looking for things which are not there, their brain brimming with ideas, their enthusiasm always worked up to a high pitch. To a scientist the modern soldier is no less intriguing when he realizes the complexity of the modern army, which uses intricate weapons. The soldier makes a demand on the scientist who not only satisfies this demand by producing a machine which is simple to operate but even suggests to the soldier the possible developments that may help to achieve nation

Structure and odd--even staggering of Mo, Ru, and Pd even--even nuclei in the framework of IBM-1

In this study, we employed the interacting boson model (IBM-1) to determine the most appropriate Hamiltonian for the study of ^{94-108}Mo, ^{94-110}Ru, and ^{96-114}Pd isotopes in the region A cong 100. The soft rotor formula (SRF) calculation was also done to study these isotopes. Using the best fit values of parameters to construct the Hamiltonian of the IBM-1 we calculated energy levels and B(E2) values for number of transitions in Mo, Ru, and Pd nuclei. The results obtained from the IBM-1 and SRF were compared with experimental data and IBM-2 calculation. On comparing the results it was observed that they were in good agreement with each other. The gamma-band energy staggering in low-spin, back bending effect, low energy spectra of even-even Mo, Ru, and Pd nuclei is also discussed.

Analytical solutions to zeroth-order dispersion relations of a cylindrical metallic nanowire near the backbending point

Zeroth-order complex dispersion relations of a cylindrical metallic nanowire have been solved out analytically with approximate methods. The analytical solutions are valid for the sections of the dispersion relations whose frequencies are close to the Surface Plasmon frequency. The back bending of the Surface Plasmon-Polaritons(SPPs) can be well described by the analytical solutions, confirming that the back bending is originated from the metal Ohmic loss. The utility of the back bending point in the dispersion relation for the measurement of the metallic Ohimc loss has also been suggested.

Melting of Argon Cluster: Dependence of Caloric Curves on MD Simulation Parameters

We report on molecular dynamics simulations performed using microcanonical ensemble to predict the melting of argon particles in nanometer size range 10 nm and to investigate the effect of the time step integration. We use the Lennard- Jones potential functions to describe the interatomic interactions, and the results are evaluated by using caloric curves of the melting phenomenon. Thermodynamic properties, including the total energy, Lindemann parameter, kinetic and potential distribution’s functions, are used to characterize the melting process. The data shows bimodal behavior only in a certain interval of integration time step Δt, while the internal energy increases monotonically with the temperature. For the other time step values, the back bending disappears. We claim that negative specific heat is related to a possible decrease of entropy in an isolated system; this can be interpreted as a result of the internal interactions, especially attractive process and specific relaxation time.

Development and modeling of an electrothermally MEMS microactuator with an integrated microgripper

Electrothermal microactuators have a promising future in microelectromechanical systems applications due to their capabilities of generating considerable mechanical deflection and forces at relatively low voltages. Moreover, their compatibility with existing CMOS technology as well as the small device area makes them very attractive for various applications. The current study introduces electrical and thermal analysis, modeling, fabrication and characterization of a thermal microactuator with an integrated microgripper. The analysis and modeling results were validated against experimental findings, and very good agreement was obtained. Furthermore, the device attains good tunability and no back bending was observed.

On the Equilibrium between Alkyne and Olefin Platinum(II) Complexes of Zeise’s Salt Type: Syntheses and Characterization of [K(18C6)][PtCl3(RC≡CR′)

Zeise’s type alkyne complexes [K(18C6)][PtCl3(RC≡CR′)] (R/R′ = Me/Me, 3; Et/Et, 4; Me/t-Bu, 5; t-Bu/t-Bu, 6; Me/Ph, 7; Me/CO2Me, 8; RC≡CR′ = COC, 9; COC = cyclooctyne; 18C6 = 18-crown-6) were obtained from the cis-but-2-ene complex [K(18C6][PtCl3(cis-but-2-ene)] (2) and the requisite alkyne via a ligand substitution reaction. 1H NMR spectroscopically determined equilibrium constants showed that the formation of all these alkyne complexes is endergonic, except that of the cyclooctyne complex 9, which is strongly exergonic. The identities of the complexes were proved by microanalysis and NMR spectroscopy (1H, 13C). X-ray diffraction analyses of complexes 5–7 exhibited slightly elongated C≡C triple bonds (1.23(1)–1.24(1) Å) and a back bending of the substituents on the alkyne between 16(1)° and 21(1)°. In contrast, a longer C≡C bond (1.27(1) Å) was found for the cyclooctyne complex 9, whereas the C–C≡C angles in this complex (26.8(7)°/26.0(7)°) are the same as in the noncoordinated cyclooctyne (26(2)°). Quantum chemical calculations on the DFT level of theory of the complex anions [PtCl3(RC≡CR′)]− (3a′–9a′) showed analogous structural features for the coordinated alkynes. Furthermore, energy decomposition analysis exhibited that the extraordinarily high stability of the cyclooctyne complex 9a′ can be understood in terms of a very low preparation energy of the cyclooctyne (due to the “prebended” structure of the noncoordinated COC) and a relatively high (instantaneous) interaction energy. NBO analyses made clear that the π back-donation in complexes bearing alkynes with electron-withdrawing substituents (Ph, CO2Me) and in the COC complex is significantly greater than that in complexes bearing alkynes with alkyl substituents (Me, Et, t-Bu).

High-spin structure and multiphononγvibrations in very neutron-richRu114

High-spin levels of the neutron-rich $^{114}\mathrm{Ru}$ have been investigated by measuring the prompt $\ensuremath{\gamma}$ rays in the spontaneous fission of $^{252}\mathrm{Cf}$. The ground-state band and one-phonon $\ensuremath{\gamma}$-vibrational band have been extended up to 14${}^{+}$ and 9${}^{+}$, respectively. Two levels are proposed as the members of a two-phonon $\ensuremath{\gamma}$-vibrational band. A back bending (band crossing) has been observed in the ground-state band at $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}$ 0.40 MeV. Using the triaxial deformation parameters, the cranked shell model calculations indicate that this back bending in $^{114}\mathrm{Ru}$ should originate from the alignment of a pair of ${h}_{11/2}$ neutrons. Triaxial projected shell model calculations for the $\ensuremath{\gamma}$-vibrational band structures of $^{114}\mathrm{Ru}$ are in good agreement with the experimental data. However, when using the oblate deformation parameters, both of the above-calculated results are not in agreement with the experimental data.

Lengthening But Not Shortening History of Paraspinal Muscle Spindles in the Low Back Alters Their Dynamic Sensitivity

Proprioception is considered important for maintaining spinal stability and for controlling posture and movement in the low back. Previous studies demonstrate the presence of thixotropic properties in lumbar muscle spindles, wherein a vertebra's positional history alters spindle responsiveness to position and movement. This study investigated whether a vertebra's movement history affects the velocity sensitivity of paraspinal muscle spindles in the low back. Afferent activity from multifidus and longissimus muscle spindles was recorded in the L(6) dorsal root in 30 anesthetized cats. To alter movement history, a feedback-controlled motor attached to the L(6) spinous process held (conditioned for 4 s) the L(6) vertebra at an intermediate position or at positions that either lengthened or shortened the muscles. With the vertebra returned to the intermediate position, resting spindle discharge was measured over the next 0.5 s (static test) and then during a dynamic test consisting of ramp vertebral movement at four velocities (0.2, 0.5, 1.0, 2.0 mm/s). Spindle activity during the tests was measured relative to hold-intermediate. For both tests, hold-long decreased and hold-short increased muscle spindle responsiveness. For the static test position responsiveness was not different among the velocity protocols for either hold-long or hold-short (P = 0.42 and 0.24, respectively). During the dynamic test, hold-long conditioning significantly decreased [F((3,119)) = 7.99, P < 0.001] spindle responsiveness to increasing velocity. Mean velocity sensitivity was 4.44, 3.39, and 1.41 (impulses/s)/(mm/s) for the hold-short, hold-intermediate, and hold-long protocols, respectively. The nearly 2.5-fold decrease in velocity sensitivity following hold-long was significantly less than that for either hold-intermediate (P = 0.005) or hold-short conditioning (P < 0.001). Hold-short conditioning had little effect on velocity responses during the dynamic test [F((3,119)) = 0.23, P = 0.87]. In conclusion, only movement histories that stretch but not shorten muscle spindles alter their velocity sensitivity. In the low back, forward flexion and lateral bending postures would likely be the most provocative.

Impact of asanas and pranayama on blood oxygen saturation level

Consistent practice of yoga postures and pranayama increases the lung's airflow, air capacity, stamina and efficiency. Back bending postures open the chest, improving both lung and heart functions. Upper back...

119 구급대원 구급활동의 근골격계 증상 및 위험실태

Fire service personnel and ambulance paramedics suffer musculoskeletal disorders as they lift and carry patients while performing Emergency Medical Services (EMS). The objective of the current study was performed to examine the association between working environment and musculoskeletal disorders of 119 paramedics and to analysis the EMS activities for them through basic survey (including task characteristics, risk factors, symptoms and illnesses). Observational job analysis of EMS activities indicated the squatting posture during first-aid performed on floor and the abrupt use of force during carrying heavy load including stretcher with patients on as hazard factors, and excessive low back twisting and bending during stairway transfer was observed. In addition, work-physiological assessment revealed various but rather high lumbar muscle usage rate among the study subjects, being 14.6~32.8% compared with Maximum Voluntary Contraction (MVC) during patients transfer work. Resting heart rate showed 65/min, on the other hand, heart rate on mobilization indicated maximum 124~156/min. Therefore, the results of analysis to the EMS activities, rescuer activities and medical tasks were accompanied with high possibility of accident and musculoskeletal disorders. Also, EMS activities indicated high muscle fatigue and energy consumption, and accumulated muscle fatigue with during continued work.

Thermal Degradation of Electroplated Nickel Thermal Microactuators

In this paper, the thermal degradation of laterally operating thermal actuators made from electroplated nickel has been studied. The actuators investigated delivered a maximum displacement of ca. 20 mum at an average temperature of ~ 450degC , which is much lower than that of typical silicon-based microactuators. However, the magnitude of the displacement strongly depended on the frequency and voltage amplitude of the pulse signal applied. Back bending was observed at maximum temperatures as low as 240degC. Both forward and backward displacements increase as the applied power was increased up to a value of 60 mW; further increases led to reductions in the magnitudes of both displacements. Scanning electron microscopy clearly showed that the nickel beams began to deform and change their shape at this critical power level. Compressive stress is responsible for nickel pileup, while tensile stresses, generated upon removing the current, are responsible for necking at the hottest section of the hot arm of the device. Energy dispersive X-ray diffraction analysis also revealed the severe oxidation of Ni structure induced by Joule heating. The combination of plastic deformation and oxidation was responsible for the observed thermal degradation. Results indicate that nickel thermal microactuators should be operated below 200degC to avoid thermal degradation.

Dynamic migration of rotating neutron stars due to a phase transition instability

Using numerical simulations based on solving the general relativistic hydrodynamic equations, we study the dynamics of a phase transition in the dense core of isolated rotating neutron stars, triggered by the back bending instability reached via angular momentum loss. In particular, we investigate the dynamics of a migration from an unstable configuration into a stable one, which leads to a mini-collapse of the neutron star and excites sizeable pulsations in its bulk until it acquires a new stable equilibrium state. We consider equations of state with softening at high densities, a simple analytic one with a mixed hadron-quark phase in an intermediate pressure interval and pure quark matter at very high densities, and a microphysical one that has a first-order phase transition, originating from kaon condensation. Although the marginally stable initial models are rigidly rotating, we observe that during the collapse (albeit little) differential rotation is created. We analyze the emission of gravitational radiation, which in some models is amplified by mode resonance effects, and assess its prospective detectability by interferometric detectors. We expect that the most favorable conditions for dynamic migration exist in very young magnetars. We find that the damping of the post-migration pulsations strongly depends on the character of the equation of state softening. The damping of pulsations in the models with the microphysical equation of state is caused by dissipation associated with matter flowing through the density jump at the edge of the dense core. If at work, this mechanism dominates over all other types of dissipation, like bulk viscosity in the exotic-phase core, gravitational radiation damping, or numerical viscosity.

Unusual case of camptocormia triggered by lumbar-disc herniation

A 21-year-old male patient with low back pain and marked forward bending was presented. The exaggerated lumbar flexion was preventing him to stand in erect posture but disappeared while lying. The symptoms had begun after he had lifted a heavy object. Straight-leg-raising test could not be performed properly because of the exaggerated pain. The light-touch sense was decreased on L5 and S1 dermatomes. There was no loss of muscle strength. The deep-tendon reflexes were normal. Plain graph showed mild narrowing in the L4-5 and L5-S1 intervertebral spaces. Lumbar magnetic resonance imaging revealed disc protrusions in L4-5 and L5-S1 levels. During his stay in the department, the patient was given tizanidine and tramadol, and physical therapy was performed. A paravertebral intramuscular injection with lidocaine was applied. Moreover, the patient was referred to psychiatrist for evaluation regarding his medical history of conversive seizures and possible efforts for secondary gain. No response was obtained from all the treatments. The final diagnosis was camptocormia triggered by lumbar-disc herniation. He was applied supportive psychotherapy, psychoeducation regarding secondary gain, strong suggestions to improve posture, positive reinforcement, and behavioral therapy. His postural abnormality resolved and disappeared completely with mild pain.

Equation of state of neutron star cores and spin down of isolated pulsars

We study possible impact of a softening of the equation of state by a phase transition, or appearance of hyperons, on the spin evolution of isolated pulsars. Numerical simulations are performed using exact 2-D simulations in general relativity. The equation of state of dense matter at supranuclear densities is poorly known. Therefore, the accent is put on the general correlations between evolution and equation of state, and mathematical strictness. General conjectures referring to the structure of the one-parameter families of stationary configurations are formulated. The interplay of the back bending phenomenon and stability with respect to axisymmetric perturbations is described. Changes of pulsar parameters in a corequake following instability are discussed, for a broad choice of phase transitions predicted by different theories of dense matter. The energy release in a corequake, at a given initial pressure, is shown to be independent of the angular momentum of collapsing configuration. This result holds for various types of phases transition, with and without metastability. We critically review observations of pulsars that could be relevant for the detection of the signatures of the phase transition in neutron star cores.

Phase transitions in rotating neutron stars cores: back bending, stability, corequakes, and pulsar timing

The back-bending phenomenon for compact stars is studied by means of analytical equations of state, for both constant-pressure phase transitions and the transitions through the mixed-phase region. We restrict ourselves to the case of normal rotating configurations, with baryon mass below the maximum allowable baryon mass for non-rotating stars. We use high-precision 2-D multi-domain spectral code LORENE to search the parameter space for possible instability regions, and possible changes in the stability character of rotating stars with phase transitions in their cores. Conditions on the density jump in constant-pressure phase transitions, leading to the existence of the unstable segments in the evolutionary sequences of spinning down isolated normal neutron stars, are derived. Conjectures concerning the existence of two disjoint families of non-rotating and rotating stationary configurations of neutron stars are formulated. Particular case of EOSs leading to marginal instability of static and rotating configurations is also studied: marginal instability point in non-rotating configurations continues to exist in all evolutionary spin-down tracks. The fate of rotating stars entering the region of instability is discussed. The change in radius, energy release, and spin-up associated with the corequake in rotating neutron star, triggered by the instability, are calculated. The energy release is found to be very weakly dependent on the angular momentum of collapsing star.

Development of thermal actuators with multi-locking positions

To reduce power consumption and operation temperature for micro-thermal actuators, metal-based micro-mechanical locks with multi-locking positions were analyzed and fabricated. The micro-locks consist of two or three U-shaped thermal actuators. The devices were made by a single mask process using electroplated Ni as the active material. Tests showed that the metal based thermal actuators deliver a maximum displacement of ∼20µm at a much lower temperature than that of Si-based actuators. However Ni-actuators showed a severe back bending, which increases with increasing applied power. The temperature to initiate the back bending is as low as ∼240°C. Back bending increases the distance between the two actuators, and leads to locking function failure. For practical application, Ni-based thermal actuators must be operated below 200°C.

Strange matter in rotating compact stars

We have constructed equations of state involving various exotic forms of matter with large strangeness fraction such as hyperon matter, Bose–Einstein condensates of antikaons and strange quark matter. First-order phase transitions from hadronic to antikaon condensed and quark matter are considered here. The hadronic phase is described by the relativistic field theoretical model. Later those equations of state are exploited to investigate models of uniformly rotating compact stars. The effect of rotation on the third family branch for the equation of state involving only antikaon condensates is investigated. We also discuss the back bending phenomenon due to a first-order phase transition from K− condensed to quark matter.

Rotating compact stars with exotic matter

We have constructed models of uniformly rotating compact stars including hyperons, Bose-Einstein condensates of antikaons and quarks. First order phase transitions from hadronic to antikaon condensed matter and then to quark matter are considered here. For the equation of state undergoing phase transitions to antikaon condensates, the third family of compact stars are found to exist in the fixed angular velocity sequences. However, the third family solution disappears when the compact stars rotate very fast. For this equation of state, the fixed baryon number supramassive sequence shows a second stable part after the unstable region but no back bending phenomenon. On the other hand, we observe that the rotation gives rise to a second maximum beyond the neutron star maximum for the equation of state involving phase transitions to both antikaon condensed and quark matter. In this case, the back bending phenomenon has been observed in the supramassive sequence as a consequence of the first order phase transition from $K^-$ condensed to quark matter. And the back bending segment contains stable configurations of neutron stars.