Axis Distance Research Articles

Simulation Study on Pipeline Deformation Defect Detection Based on Eddy Current Effect

Oil and gas pipeline deformation detector is of great significance for pipeline deformation detection. In view of the poor throughput of small diameter oil and gas pipelines, this paper presents an internal deformation detection technology based on eddy current effect. Based on the eddy current theory, a mathematical model for eddy current testing of pipeline deformation defects is established. The relationship between probe lift-off value and magnetic field intensity is studied by numerical calculation method. The results show that under the same lift-off value, the composite magnetic field intensity is negatively correlated with the axis distance of the excitation coil, and at the same position, the composite magnetic field intensity is positively correlated with the lift-off value. The research in this paper has certain guiding significance for the internal detection technology of pipeline deformation defect.

What is the difference in morphologic features of the lumbar vertebrae between Caucasian and Taiwanese subjects? A CT-based study: implications of pedicle screw placement via Roy-Camille or Weinstein method

BackgroundSafe placement of pedicle screws without jeopardizing neurovascular structures medially and anteriorly is important during spine surgery. Inferior breach of pedicle is also dangerous due to low margin of error. Lumbar morphology and identical pedicle orientation at L1 to L5 shown on CT scan of young Taiwanese patients (90 patients) were analyzed and compared with findings reported for Caucasian subjects.MethodsPreviously reported techniques were employed to quantitatively elucidate the parameters regarding lumbar morphology and identical pedicle orientation at each vertebra. The parameters for pedicle angle (PA), pedicle diameter (PD), pedicle axis distance (PAD), midline axis distance (MAD), transverse pedicle axis distance (TPAD) and transverse intertangential angle (TITA) were measured.ResultsTaiwanese subjects had different PA, PD, PAD, MAD at L1 to L5 and TITA at L3 to L5 compared with Caucasian subjects. L5 had the most convergent pedicle axis, the widest PD and the shortest antero-posterior axis morphology.ConclusionsThis study provides detailed information for identifying pedicle orientation during pedicle screw placement and elucidate racial differences in lumbar morphology and pedicle orientation between Taiwanese and Caucasian populations.

Promoting the Cyclic Performance and Boosting Li+transport of LiV3O8 Via Ca Doping

As one of the most promising cathodes for rechargeable Lithium ion battery, LiV3O8 commonly suffers from inevitably complicated phase transitions and sluggish kinetics. Here, we develop a Ca doping technique totackle this long-standing issue of instability and improve the rate performance of LiV3O8. The dopants are found to reside in the Li site ofLiV3O8, where works as a pillar to increase the a axis distance facilitating Li diffusion, stabilizing the structure and suppressing the phase transition during cycling. This doped LiV3O8 displays an exceptionally high capacity of 280 mAh g-1, cyclability with 87% capacity retention over 100 cycles and significantly enhanced rate capability.

Clinical efficacy of laminectomy with instrumented fixation in treatment of adjacent segmental disease following ACCF surgery: a retrospective observational study of 48 patients

This study was designed to investigate the clinical efficacy of laminectomy with instrumented fixation in treatment of adjacent segmental diseases following anterior cervical corpectomy and fusion (ACCF) surgery. Between January 2008 and December 2015, 48 patients who underwent laminectomy with instrumented fixation to treat adjacent segmental diseases following ACCF surgery, were enrolled into this study. The patients were followed up at least 2 years. Pain assessment was determined by visual analogue scale (VAS) score and Neck Disability Index (NDI) score; neurological impairment was evaluated by Japanese Orthopaedic Association (JOA) score; and radiographic parameters were also compared. All comparisons were determined by paired t test with appropriate Bonferronni correction. VAS score preoperatively and at last follow-up was 5.28 ± 2.35 vs 1.90 ± 1.06 (P < 0.001). JOA score preoperatively and at last follow-up was 8.2 ± 3.6 vs 14.5 ± 1.1 (P < 0.001). NDI score preoperatively and at last follow-up was 30.5 ± 12.2 vs 10.6 ± 5.8 (P < 0.001). Moreover, the losses of cervical lordosis and C2-C7 range of motion after laminectomy were significant (both P < 0.005), but not sagittal vertical axis distance. Postoperative complications were few or mild. In conclusion, clinical effectiveness and safety can be guaranteed when the patients undergo laminectomy with instrumented fixation to treat adjacent segmental diseases following ACCF surgery.

Large-format pulse-dilation framing tube with 5 lp/mm spatial resolution

A pulse-dilation framing tube consisting of a pulse-dilation device, a magnetic lens imaging system, and a microchannel plate (MCP) imager is reported. Three are three photo-cathodes coated with 80 nm Au on a 90 mm diameter C8H8 film. And a sensitive area with diameter of about 60 mm is achieved. The magnetic lens imaging system images the photoelectrons from photo-cathode (PC) onto MCP with the image ratio of 2:1. The spatial resolution of the pulse-dilation framing tube is measured, which is about 5 lp/mm. Furthermore, the spatial resolution will be worse with the increasing off axis distance.

Use of the WALA ridge to evaluate mandibular molar inclination measured to American Board of Orthodontics standards

ObjectiveEvaluation of mandibular molar inclination provides valuable information to the orthodontist when evaluating posterior functional occlusal relationships, diagnosing and treating transverse skeletal and dental relationships, and assessing the quality of orthodontic treatment finishing. Traditional evaluation methods rely on radiographs or diagnostic dental models. Identification of a clinical anatomic landmark that can be evaluated chairside and reliably produces desired treatment results would prove valuable to the clinician. Materials and MethodsPlaster dental casts of 60 posttreatment patients were evaluated for mandibular molar inclination by American Board of Orthodontics (ABO) Cast-Radiograph evaluation standards and compared with the mandibular anatomic landmark the WALA ridge. ResultsMandibular first molars conforming to ABO standards with a vertical difference in buccal and lingual cusp heights ≤1.0 mm had an average horizontal WALA-facial axis (FA) distance of 2.56 mm, which was significantly smaller than the 3.11 mm found when molars were ABO nonconforming with vertical cusp height differences of >1.0 mm to ≤2.0 mm (P < 0.001). Mandibular first molars with WALA-FA distances of ≤2.5 mm were not significantly more likely to be ABO conforming than those with WALA-FA distances of >2.5 mm. ConclusionsMandibular molars with vertical differences in buccal and lingual cusp heights meeting the ABO standards for inclination have significantly smaller horizontal tooth to mandibular bone distances (WALA-FA).

A Dual-Interferometer-Based Angular Measurement System With Absolute Angle Recovery Method

A dual-interferometer-based angular measurement system is proposed and studied, obtaining analytical expressions for the measured distance of each interferometric axis. The nonzero convexity of the characteristic curve during a rotation is proven to be an intrinsic characteristic of the setup. An absolute angle recovery method is proposed relying on the use of this characteristic curve as an absolute reference to overcome the limitation of the relative operation of conventional interferometric systems. The recovery method is evaluated by Monte Carlo simulations, studying the effect of the noise and the number of points on the performance of the recovery. Finally, the technique is successfully applied to a high-precision rotational stage, where an independent dual-interferometer system is used to experimentally evaluate the performance of the method. The results show an accuracy of $\pm 1.29~\mu $ rad ( $3\sigma $ ) in the recovery of the angle, which is in agreement with the Monte Carlo simulations.

The influence of AZO films on morphology and surface plasmon resonance properties of Ag particles

Ag particles based Al-doped zinc oxide (AZO) films on glass substrates were prepared by magnetron sputtering method and then thermal annealing treatment. The crystallization quality and surface morphology of AZO films and thermal annealing treatment have an important effect on the thermal diffusion growth of Ag particles, which can greatly determine the morphology, size distribution and surface plasmon resonance (SPR) properties of Ag. Compared with spherical Ag particles, the elongated Ag elliptical particles formed on AZO films with better crystalline quality and smaller surface roughness after annealing exhibit red shift of SPR peaks. An effective finite difference time domain (FDTD) model is built to investigate the SPR mechanism of elongated elliptical Ag particles. It is found that elongated elliptical Ag particles are more likely to exhibit SPR properties in long wavelengths intensely depending on transverse surface plasmon (TSP) and longitudinal surface plasmon (LSP) modes. The large average particle size and decrease of inter-particle spacing of elongated elliptical Ag particles corresponding to LSP mode lead to the redshift of SPR. Moreover, the elongated elliptical Ag particles with large long axis distance could be more conductive, and RS value of those Ag based AZO film reaches to 9.6 Ω/sq after annealing at 350 °C.

Variability of the helical axis during active cervical movements in people with chronic neck pain

BackgroundRecent work described parameters of the helical axis in asymptomatic people with potential for investigating kinematic changes in the cervical region. This approach could provide novel information on movement variability in people with neck pain, however this has never been investigated. This study aimed to investigate movement variability during active neck movements performed at different speeds in people with and without chronic neck pain. MethodsThis observational case-control study examined 18 participants with chronic neck pain of either idiopathic or traumatic origin and 18 gender-matched asymptomatic participants. Cervical kinematics were captured with 3D motion capture as people with and without chronic neck pain performed flexion-extension, bilateral lateral flexion and bilateral rotation at different speeds (natural, slow, and fast). The mean distance and mean angle parameters of the helical axis were extracted to describe 3D motion and quantify movement variability. FindingsA smaller mean distance was observed in those with neck pain compared to the asymptomatic participants during flexion-extension (P = 0.019) and rotation movements (P = 0.007). The neck pain group displayed smaller values for the mean angle during rotation movements with different speeds (P = 0.01). These findings indicate less variable movement for those with neck pain relative to the asymptomatic participants. No difference in the mean angle was observed between groups for flexion-extension and lateral flexion. InterpretationThe findings reiterate the importance of data derived from kinematic measures, and its potential for providing clinicians with further insight into the quality of active neck movements in people with chronic neck pain.

Radiographic Analysis of Minimally Invasive Transforaminal Lumbar Interbody Fusion versus Conventional Open Surgery on Sagittal Lumbar-Pelvic Alignment for Degenerative Spondylolisthesis

To compare the impact of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with open posterior lumbar interbody fusion (PLIF) on sagittal lumbar-pelvic radiographic parameters for degenerative spondylolisthesis (DS). Of 48 patients with L4 single segmental DS, 25 underwent MIS-TLIF with Quadrant system and 23 underwent conventional open PLIF. Comparisons of data from the preoperative and final follow-up standing lateral lumbar x-rays, with the bilateral femoral heads, of the 2 groups were conducted using the following parameters: slip percentage (SP), lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope, lumbosacral angle, slip angle (SA), and the L1 axis and S1 distance (LASD). The slip reduction rate (ΔSP) in the OPEN group was significantly higher than in the MIS group (67 ± 34% vs. 37 ± 51%, P= 0.018). The change of SA (ΔSA) in the OPEN group was significantly higher than in the MIS group (3 ± 7° vs. -3 ± 5°, P= 0.003). The change of LASD (ΔLASD) in the OPEN group was significantly lower than in the MIS group (-4 ± 15 mm vs. 4 ± 9 mm, P= 0.033). There were positive correlations between the preoperative SP and LASD, and ΔSA and the change of LL (ΔLL), and a negative correlation between ΔLL and the change of PT (ΔPT). For low-grade DS, open PLIF has a higher rate of slip reduction compared to MIS-TLIF, and significantly reduces LASD, therefore, it is more conducive to improving lumbar sagittal balance.

Kinematics of the outer halo of M 87 as mapped by planetary nebulae

Aims. We present a kinematic study of a sample of 298 planetary nebulas (PNs) in the outer halo of the central Virgo galaxy M 87 (NGC 4486). The line-of-sight velocities of these PNs are used to identify subcomponents, to measure the angular momentum content of the main M 87 halo, and to constrain the orbital distribution of the stars at these large radii. Methods. We use Gaussian mixture modelling to statistically separate distinct velocity components and identify the M 87 smooth halo component, its unrelaxed substructures, and the intra-cluster (IC) PNs. We compute probability weighted velocity and velocity dispersion maps for the smooth halo, and its specific angular momentum profile (λR) and velocity dispersion profile. Results. The classification of the PNs into smooth halo and ICPNs is supported by their different PN luminosity functions. Based on a Kolmogorov–Smirnov (K–S) test, we conclude that the ICPN line-of-sight velocity distribution (LOSVD) is consistent with the LOSVD of the galaxies in Virgo subcluster A. The surface density profile of the ICPNS at 100 kpc radii has a shallow logarithmic slope, −αICL ≃ −0.8, dominating the light at the largest radii. Previous B − V colour and resolved star metallicity data indicate masses for the ICPN progenitor galaxies of a few ×108 M⊙. The angular momentum-related λR profile for the smooth halo remains below 0.1, in the slow rotator regime, out to 135 kpc average ellipse radius (170 kpc major axis distance). Combining the PN velocity dispersion measurements for the M 87 halo with literature data in the central 15 kpc, we obtain a complete velocity dispersion profile out to Ravg = 135 kpc. The σhalo profile decreases from the central 400 km s−1 to about 270 km s−1 at 2–10 kpc, then rises again to ≃300 ± 50 km s−1 at 50–70 kpc, to finally decrease sharply to σhalo ∼ 100 km s−1 at Ravg = 135 kpc. The steeply decreasing outer σhalo profile and the surface density profile of the smooth halo can be reconciled with the circular velocity curve inferred from assuming hydrostatic equilibrium for the hot X-ray gas. Because this rises to νc,X ∼ km s−1 at 200 kpc, the orbit distribution of the smooth M 87 halo is required to change strongly from approximately isotropic within Ravg ∼ 60 kpc to very radially anisotropic at the largest distances probed. Conclusions. The extended LOSVD of the PNs in the M 87 halo allows the identification of several subcomponents: the ICPNs, the “crown” accretion event, and the smooth M 87 halo. In galaxies like M 87, the presence of these subcomponents needs to be taken into account to avoid systematic biases in estimating the total enclosed mass. The dynamical structure inferred from the velocity dispersion profile indicates that the smooth halo of M 87 steepens beyond Ravg = 60 kpc and becomes strongly radially anisotropic, and that the velocity dispersion profile is consistent with the X-ray circular velocity curve at these radii without non-thermal pressure effects.

Hydrodynamic Performance Analysis of the Vertical Axis Twin-Rotor Tidal Current Turbine

The goal of this manuscript is to investigate the influence of relative distance between the twin rotors on the hydrodynamic performance of the vertical axis twin-rotor tidal current turbine. Computational fluid dynamics (CFD) simulations based on commercial software ANSYS-CFX have been performed to enhance the understanding of interactions between the twin-rotors. The interactions between the twin rotors are known to have increased the power output efficiency as a whole, and it is, therefore, of great significance to undertake deeper research. The simulation results are found to be consistent with similar research results in the literature in some aspects. The simulation results of stand-alone turbine and twin rotors are compared from three different aspects, including blade forces, power output efficiency and wake flow field. The results showed that the cyclic variations tendency of blade force coefficients of twin rotors is close to that of the stand-alone turbine. The average power output efficiency of the twin-rotors system is higher than that of the stand-alone turbine. The interactions between the turbines increase the power output of the twin turbine system as whole in a wide relative distance range. However, smaller relative distance between the twin rotors does not mean a bigger power output efficiency of such a system. The power out efficiency of such a system would decrease when the relative distance between the twin rotors exceeds the critical point. The power output of the twin rotors reaches the peak value when the ratio between the two main axis distance and diameter of the turbine is around 9/4. This research can provide a reference for the design and development of larger tidal power stations.

Buoyancy-induced convection of water-based nanofluids from an enclosed heated cylinder

PurposeLaminar natural convection of nanofluids in a square cooled cavity enclosing a heated horizontal cylinder is studied numerically. This paper aims to investigate in what measure the nanoparticle size and average volume fraction, the cavity width, the cylinder diameter and position, the average temperature of the nanofluid and the temperature difference imposed between the cylinder and the cavity walls, affects the basic heat and fluid flow features, as well as the thermal performance of the nanofluid relative to that of the base liquid.Design/methodology/approachThe four-equation system of the mass, momentum and energy transfer governing equations has been solved using a computational code incorporating three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity and the coefficient of thermophoretic diffusion, all based on a high number of experimental data available in the literature. The SIMPLE-C algorithm has been used to handle the pressure-velocity coupling. Simulations have been performed using Al2O3 + H2O, for different values of the average volume fraction of the suspended solid phase in the range 0-0.04, the diameter of the nanoparticles in the range 25-75 nm, the temperature difference imposed between the cylinder and the cavity walls in the range 5-20 K, the average nanofluid temperature in the range 300-330 K, the ratio between the cylinder diameter and the cavity width in the range 0.1-0.5 m, the ratio between the distance of the cylinder axis from the bottom wall and the cavity width in the range 0.2-0.8 and the ratio between the distance of the cylinder axis from the left sidewall and the cavity width in the range 0.2-0.5.FindingsThe main results obtained may be summarized as follows: the overall solid phase migration from hot to cold results in a cooperating solutal buoyancy force which tends to compensate the friction increase consequent to the viscosity growth due to the dispersion of the nanoparticles into the base fluid; the effect of the increased thermal conductivity consequent to the nanoparticle dispersion into the base fluid plays the major role in determining the heat transfer enhancement of the nanofluid, at least in the upper range of the investigated average temperatures; at high temperatures, the nanofluid heat transfer performance relative to that of the pure base liquid increases with increasing the average volume fraction of the suspended solid phase, whereas at low temperatures, it has a peak at an optimal particle loading; the relative heat transfer performance of the nanofluid increases notably with increasing the average temperature, and just moderately as the imposed temperature difference, the width of the cavity and the distance of the cylinder from the bottom of the cavity, are increased; the relative heat transfer performance of the nanofluid increases as the nanoparticle size, the cylinder diameter and the distance of the cylinder from the sidewall, are decreased; as a consequence of the local competition between the thermal and the solutal buoyancy forces, a periodic flow arises when the cylinder is located in the vicinity of one of the cooled walls of the enclosure.Originality/valueFramed in this general background, a comprehensive numerical study on buoyancy-driven convection of alumina-water nanofluids inside a cooled square cavity containing a heated circular cylinder is executed by the way of a two-phase model based on the double-diffusive approach accounting for the effects of the Brownian diffusion and thermophoresis.

The optimization of coal on-line analysis system based on signal-to-noise ratio evaluation

In the present study, the coal on-line analysis system is optimized, and the signal-to-noise ratio (SNR) is quantified and set as the evaluation criterion for device optimization. 3 cm lead with 3 cm polyethylene is set as moderator, and 13 cm lead is for a better shielding. Besides, the neutron generator is set at the center of device, and 72 cm is set as the better distance of axis between neutron generator and detector. Finally, by comparing with the previous experimental results, the Mean Absolute Percentage Error of element with the value less than 1% is improved after device optimization by SNR evaluation.

On the design of an electromagnetic aeroelastic energy harvester from nonlinear flutter

A new energy harvester by coupling the electromagnetic induction and the pitch vibration of a rigid wing is built up in this paper. It is aimed: (1) to harvest energy from the pitch limit cycle oscillation (LCO) of the wing due to the preloaded free-play nonlinearity; (2) to introduce a theoretical analysis scheme based on the equivalent linearized method into the design of this harvester. With the equivalent linearized method, the domains of the single stable LCO and double stable LCOs are respectively obtained. Combining the analytical and numerical solutions, the single stable LCO along with the stable limit cycle amplitude greater than its corresponding unstable one is recognized as the better mode for harvesting, since the larger limit cycle domain is induced and the more energy are yielded. Based on such chosen mode, analyses of varying parameters are conducted with respect to the plunge stiffness, pitch stiffness, distance of elastic axis from center of gravity, distance of geometric center from elastic axis, load resistance and magnetic flux density. Meanwhile, three indicators are applied to reveal their effects on the harvesting performances: (1) the size of limit cycle domain, (2) the onset velocity of LCO, and (3) the energy output.

Approaching the capacity limit of lithium cobalt oxide in lithium ion batteries via lanthanum and aluminium doping

Lithium cobalt oxides (LiCoO2) possess a high theoretical specific capacity of 274 mAh g–1. However, cycling LiCoO2-based batteries to voltages greater than 4.35 V versus Li/Li+ causes significant structural instability and severe capacity fade. Consequently, commercial LiCoO2 exhibits a maximum capacity of only ~165 mAh g–1. Here, we develop a doping technique to tackle this long-standing issue of instability and thus increase the capacity of LiCoO2. La and Al are concurrently doped into Co-containing precursors, followed by high-temperature calcination with lithium carbonate. The dopants are found to reside in the crystal lattice of LiCoO2, where La works as a pillar to increase the c axis distance and Al as a positively charged centre, facilitating Li+ diffusion, stabilizing the structure and suppressing the phase transition during cycling, even at a high cut-off voltage of 4.5 V. This doped LiCoO2 displays an exceptionally high capacity of 190 mAh g–1, cyclability with 96% capacity retention over 50 cycles and significantly enhanced rate capability. Lithium cobalt oxides are used as a cathode material in batteries for mobile devices, but their high theoretical capacity has not yet been realized. Here, the authors present a doping method to enhance diffusion of Li ions as well as to stabilize structures during cycling, leading to impressive electrochemical performance.

Validation of prone intraoperative measurements of global spinal alignment.

OBJECTIVE Verifying the adequacy of surgical correction of adult spinal sagittal deformity (SSD) leads to improved postoperative alignment and clinical outcomes. Traditionally, surgeons relied on intraoperative measurements of lumbar lordosis (LL) correction. However, T-1 pelvic angle (TPA) and its component angles more reliably predict postoperative alignment. While TPA is readily measured on standing radiographs, intraoperative radiographs offer poor resolution of the bicoxofemoral axis. A method to recreate this radiographic landmark by extrapolating preoperative measurements has been described. The authors aimed to assess the reliability of measurements of global spinal alignment obtained via geometrical reconstitution of the bicoxofemoral axis on prone intraoperative radiographs. METHODS A retrospective review was performed. Twenty sets of preoperative standing full-length and intraoperative prone 36-inch lateral radiographs were analyzed. Pelvic incidence (PI) and sacral to bicoxofemoral axis distance (SBFD) were recorded on preoperative films. A perpendicular line was drawn on the intraoperative radiograph from the midpoint of the sacral endplate. This was used as one limb of the PI, and the second limb was digitally drawn at an angle that reproduced the preoperatively obtained PI, extending for a distance that matched the preoperative SBFD. This final point marked the obscured bicoxofemoral axis. These landmarks were used to measure the L-1, T-9, T-4, and T-1 pelvic angles (LPA, T9PA, T4PA, and TPA, respectively) and LL. Two spine fellows and 2 attending spine surgeons made independent measurements and repeated the process in 1 month. Mixed-model 2-way intraclass correlation coefficient (ICC) and Cronbach's α values were calculated to assess interobserver, intraobserver, and scale reliability. RESULTS Interobserver reliability was excellent for preoperative PI and intraoperative LPA, T9PA, and T4PA (ICC = 0.88, 0.84, 0.84, and 0.93, respectively), good for intraoperative TPA (ICC = 0.68), and fair for preoperative SBFD (ICC = 0.60) and intraoperative LL (ICC = 0.50). Cronbach's α was ≥ 0.80 for all measurements. Measuring PI on preoperative standing images had excellent intraobserver reliability for all raters (ICC = 0.89, range 0.80-0.93). All raters but one showed excellent reliability for measuring the SBFD. Reliability for measuring prone LL was good for all raters (ICC = 0.71, range 0.64-0.76). The LPA demonstrated good to excellent reliability for each rater (ICC = 0.76, range 0.65-0.81). The thoracic pelvic angles tended to be more reliable at more distal vertebrae (T9PA ICC = 0.71, range 0.49-0.81; T4PA ICC = 0.62, range 0.43-0.83; TPA ICC = 0.56, range 0.31-0.86). CONCLUSIONS Intraoperative assessment of global spinal alignment with TPA and component angles is more reliable than intraoperative measurements of LL. Reconstruction of preoperatively measured PI and SBFD on intraoperative radiographs effectively overcomes poor visualization of the bicoxofemoral axis. This method is easily adopted and produces accurate and reliable prone intraoperative measures of global spinal alignment.

Characterization of Natural Convection over an Elliptical Tubes Array AR 2.5 and PR 1.25 inside a Thermally Asymmetric Cavity of Various Clearance Ratio

Natural convection is the phenomenon of heat transfer due to the buoyancy force of fluid. One application of natural convection inside a vertical cavity is refrigerator condenser of circular cross-section tube. An experimental investigation is presented on natural convection of air over an array of elliptical tubes of AR 2.5 arranged vertically inside a thermally asymmetric cavity. One side of the cavity is insulated and the opposite side is exposed to ambient air. The distance between tubes, pitch ratio PR is constant at 1.25 where “a” is a half of tube major axis. The Clearance Ratio \textit{CR} which is the ratio between the distance of tubes array major axis to the insulated wall x and the width of the cavity y, is varied 0.4 and 0.6. The heat flux of the tube is maintained at 22.79 kW/m$^2$. It is found that the higher value of heat transfer coefficient is achieved on CR= 0.4.

Habitat use and movement patterns of small (age‐0) juvenile Pacific bluefin tuna (Thunnus orientalis) relative to the Kuroshio

AbstractThe habitat use of Pacific bluefin tuna (Thunnus orientalis; PBF) in nursery waters off the southern coast of Japan was investigated using archival tags over a 3 year study period (2012–2015), and the data were used to examine the free‐ranging habitat preferences of PBF and the relationship between their horizontal movements and the path of the Kuroshio off the Pacific coast of Japan. The path of the Kuroshio fluctuated seasonally, leading to changes in water temperature that strongly influenced the habitat use of small PBF (2–3 months after hatching). Most PBF were present in coastal waters inshore of the path of the current, and their habitat use changed in response to the distance of the current from the coast. The Kuroshio typically flowed along the coast from summer to autumn, and PBF remained in the coastal waters off Kochi Prefecture during this period. In contrast, PBF quickly moved eastward in winter when the current moved away from the coast. Throughout the winter and spring, the area of habitat use extended widely from the eastern end of the southern coast of Japan (the Boso Peninsula) to the offshore Kuroshio‐Oyashio transition region. These findings suggest that the seasonal habitat use and movement behavior of juvenile PBF are influenced by the distance of the Kuroshio axis from the coast, and the ultimate drivers are likely variations in oceanographic conditions and prey availability along the southern coast of Japan.

Cervical sagittal balance parameters after single-level anterior cervical discectomy and fusion: Correlations with clinical and functional outcomes.

Background:Normal sagittal cervical alignment has been associated with improved outcome after anterior cervical discectomy and fusion (ACDF).Objective:The aim of this study is to identify alterations of cervical sagittal balance parameters after single-level ACDF and assess correlations with postoperative functionality.Methods:A retrospective chart review was performed between January 2010 and January 2014 to identify adult patients with no previous cervical spine surgery who underwent ACDF at any one level between C2 and C7 for the single-level degenerative disease. Tumor, infection, and trauma cases were excluded from the study. For the included cases, the following data were recorded preoperatively and 6 months–1 year after surgery: sagittal balance-marker measurements of the C1–C2 angle, C2–C7 angle, C7 slope, segmental angle at the operated level, and sagittal vertical axis (SVA) distance between C2 and C7, as well as the neck disability index and visual analog scale of pain.Results:The present study included 47 patients (average age: 51.2 years; range: 28–86 years). A moderate negative correlation between a smaller C2–C7 angle and the presence of right arm pain before treatment was found (P = 0.0281). Postoperatively, functionality scores significantly improved in all patients. C1–C2 angle increased with statistical significance (P = 0.0255). C2–C7 angle, segmental angle, C7 slope, and SVA C2–C7 distance did not change with statistical significance after surgery. C7 slope significantly correlated with overall cervical sagittal balance (P < 0.05).Conclusions:Single-level ACDF significantly increases upper cervical lordosis (C1–C2) without significantly changing lower cervical lordosis (C2–C7). The C7 slope is a significant marker of overall cervical sagittal alignment (P < 0.05).