Half Height Research Articles

Multiple switching pattern for a modified reduce switch multilevel inverter: A comparison analysis

A primary concern of multilevel inverter is its capability to produce desired alternating voltage close to sinusoidal at the output, using multiple sources of DC voltage input. Mostly a multilevel inverter is used to generate the AC voltage from DC voltage. The aim of this paper is to investigate the output of 9 level multilevel inverter by modifying the conventional 5 levels H-bridge cascade multilevel inverter. The proposed design intending to reduce the number of switches from 16 switches to 10 switches. Implementation of different switching pattern methods; equal phase (EP), half equal phase (HEP), half height (HH) and feed forward (FF) and the related expression are presented in this paper. In the result section shows a different percentage of total harmonic distortion achieved. Out of all 4 methods, HH method suppressed distortion wave the most and resulted in the lowest THD in the proposed inverter. This paper shows that by reducing the number of switches in multilevel inverter structure maintains the same quality output as the conventional H-bridge topology. Furthermore, the manipulation of the switches firing angle contribute in decreasing the system THD.

Method to Determine the Thickness of the Carburized Layer of Pyrolysis Furnace Tubes Using Ultrasound Technique

Carburization that takes place in HP steel tubes in pyrolysis furnaces coils is an undesirable event, as it negatively affects mechanical and resistance to corrosion properties. This has been an important factor for the study and development of non-destructive methodologies aiming at maintaining structural integrity. In this work, non-destructive testing using ultrasound was employed for specimen with varying carburization degrees, in order to characterize them. The results allowed for the development of a correlation between the thickness of the carburized layer and of the half height bandwidth of the backwall echo frequency spectra.

The application of Box-Behnken-Design in the optimization of HPLC separation of fluoroquinolones

Box-Behnken Design is a useful tool for the optimization of the chromatographic analysis. The goal of this study was to select the most significant factors that influenced the following parameters of the chromatographic separation: retention time, relative retention time, symmetry of the peaks, tailing factor, a number of theoretical plates, Foley – Dorsey parameter, resolution factor, peak width at half height. The results underwent the ANOVA test to find the statistically significant variables and interactions between them. The level of significance was for p < 0.05. The polynomial equations described quantitatively the statistically significant parameters and the interactions between them. The statistical analysis indicated both the best conditions for the separation of the compounds and the variables that were most influential for peaks’ parameters. The four-factor analysis performed for LEVO and MOXI indicated that ACN, TEA and pH are the most significant factors that influence the separation. The analysis for the pair CIPRO and LEVO required six factors. The statistical analysis proved that the most significant factors are ACN, MeOH and TEA. In the separation of these two compounds on the HPLC column, the interaction ACN × MeOH was also significant.

Debridement and Interbody Graft Using Titanium Mesh Cage, Posterior Monosegmental Instrumentation, and Fusion in the Surgical Treatment of Monosegmental Lumbar or Lumbosacral Pyogenic Vertebral Osteomyelitis via a Posterior-Only Approach

The main objective of the present study was to analyze the efficacy and feasibility of surgical management for patients with monosegmental lumbar or lumbosacral pyogenic vertebral osteomyelitis (PVO) by using one stage posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion. From February 2014 to May 2016, 27 patients with lumbar or lumbosacral PVO were treated by posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion. The degree of damage to the patients' vertebral bodies was one third to one half height. There were 16 male and 11 female, with a mean age of 43.5 years (range, 32-56 years) at the time of surgery. The mean follow-up time was 35.7 months (range, 26-53 months). The clinical efficacy was evaluated on average operation time, blood loss, visual analog scale, erythrocyte sedimentation rate, C-reactive protein level, and neurologic function recovery. PVO was completely cured and the grafted bone was fused in all 27 patients. There was no recurrent vertebral osteomyelitis infection. Erythrocyte sedimentation rate and C-reactive protein level achieved normal limits within 3 months in all patients. The American Spinal Injury Association neurologic classification was improved in all cases. Pain relief was obtained in all patients. Our results showed that one stage posterior debridement, interbody graft using titanium mesh cage, posterior monosegmental instrumentation, and fusion was an effective treatment for patients with one third to one half height of vertebral body damaged in monosegmental lumbar or lumbosacral PVO. The surgical method is characterized as minimum surgical trauma, good pain relief, good neurologic recovery, and good reconstruction of spinal stability.

Functionalised microwave sensors for real-time monitoring of copper and zinc concentration in mining-impacted water

Microwave spectroscopy has been identified as a novel and inexpensive method for the monitoring of water pollutants. Integrating microwave sensors with developed coatings is a novel strategy to make the sensing system more specific for a target contaminant. This study describes the determination of copper and zinc concentration in water in both laboratory-prepared and acquired mine water samples from two abandoned mining areas in Wales, UK. Uncoated sensors immersed in samples spiked with 1.25 mg/L concentrations of copper and zinc, using the standard addition method, were able to quantify the concentration at 0.44 GHz with a strong linear correlation (R2 = 0.99) for the reflection coefficient magnitude (|S11|). Functionalised microwave sensors with l-cysteine, chitosan and bismuth zinc cobalt oxide-based coatings have shown improvement in the sensing performance. Specifically, the linear correlation at 0.91–1.00 GHz between |S11| and a polluted water sample spiked with Cu showed a higher (R2 = 0.98), sensitivity (1.65 ΔdB/mg/L) and quality factor (135) compared with uncoated sensors (R2 = 0.88, sensitivity of 0.82 ΔdB/mg/L and Q-factor 30.7). A Lorentzian peak fitting function was applied for performing advanced multiple peak analysis and identifying the changes in the resonant frequency peaks which are related to the change in metal ion content. This novel sensor platform offers the possibility of in situ monitoring of toxic metal concentrations in mining-impacted water, and multiple peak features, such as area, full width half maximum, centre and height of the peaks, have the possibility to offer higher specificity for similar toxic metals, as between copper and zinc ions.

Influence of the free end flow on the bistability phenomenon after two side by side finite height cylinders with aspect ratios of 3 and 4 and high blockage

This work presents an experimental study of the bistability phenomenon downstream of pairs of finite cylinders with aspect ratios h/d of 3 and 4. In finite cylinders, bistability is still poorly explored and understood. The wake flow around a single finite cylinder with Red = 2.00 × 104 was studied. After that, the flow around two finite cylinders with diameters of 25 and 32 mm and aspect ratios of 3 and 4 was studied (3.86 × 103 ≤ Red ≤ 4.81 × 104). Hot wire anemometry in an aerodynamic channel and flow visualization by ink injection in water in a hydraulic channel were employed. Analysis of hot wire data employed statistics, spectral, and wavelet tools. Video analysis was made with editing software and statistical tools. The flow visualization technique strengthens the interpretation of the results obtained through the hot wire anemometer technique. In this work three concomitant flows are considered: the upward flow, from the cylinder base; the downward flow, from the top; and the so-called main flow, by the vortex shedding at half height of the cylinders. The results show the existence of two different levels of mean velocity in time series, corresponding to two flow modes confirming the presence of the phenomenon of bistability for two finite cylinders placed side by side. Downward flow from the top of the cylinders with an aspect ratio of h/d = 4 studied also presents bistable characteristics.

Deformation of flexible fibers in turbulent channel flow

In this paper, we examine from a statistical point of view the deformation of flexible fibers in turbulent channel flow. Fibers are longer than the Kolmogorov length scale of the carrier flow and have finite inertia. Our aim is to examine the effect of local shear and turbulence anisotropy on fiber twisting and bending, when shape effects add to the inertial bias. To these aims, we use an Eulerian–Lagrangian approach based on direct numerical simulation of turbulence in dilute flow conditions. Fibers are modelled as chains of sub-Kolmogorov rods (referred to as elements hereinafter) interconnected by holonomic constraints that enable relative rotation of neighbouring elements. Statistics are computed from simulations at shear Reynolds number $${\text{Re}}_{\tau }=150$$, based on the channel half height, for fibers with different aspect ratio, $$\lambda _r$$ (defined as the ratio between the length $$l_r$$ of each element r composing the fiber and its cross-sectional radius, a), and different inertia, parameterized by the Stokes number of the element, $$St_r$$. We show that bending of flexible fibers is in general stronger in the bulk of the flow, where they are subject to turbulent velocity fluctuations only. Near the wall, fibers are more easily stretched by the mean shear, especially for large-enough inertia ($$St_r > 5$$ in our simulations). In spite of this different dynamics, which is connected to the anisotropy of the flow, we find that the fiber end-to-end distance reaches a steady state regardless of fiber location with respect to the wall.

Investigation of magnetocaloric effect: Stoner approximation vs DMFT

A comparative study of the magnetocaloric effect (MCE) in metals within the single-band Hubbard model on the face-centered cubic (fcc) lattice using both mean-field (Stoner) approximation (MFA) and dynamical mean-field theory (DMFT) is done. The MCE is investigated in the case of second order magnetic phase transition from ferromagnet to paramagnet. To ensure presence of itinerant ferromagnetism in the Hubbard model the special case of spectrum parameters generating giant van Hove singularity at the bottom of the band is considered, while the Fermi level Ef is in the vinicity of the band bottom. To compare MCE within MFA and DMFT temperature dependence of magnetization, total energy and finally entropy for a set of Coulomb interactions U at zero and finite values of magnetic field h for both methods were performed. Also one of the MCE potentials, isothermal entropy change, as a function of temperature ∆S(T) for both MFA and DMFT is calculated. In the MFA, the expected maximum value of ∆S(T) at the Curie temperature TC (∆Smax) quite significantly decreases while U grows. Similar but much weaker decreasing of ∆Smax is found for DMFT results. The account of local quantum fluctuations results in larger values of ∆Smax within DMFT than within MFA. A peak width of ∆S(T) at half height is approximately the same for both methods. Another effect of DMFT local quantum fluctuations is the destruction of anomalous Curie temperature TC dependence on U present in MFA, which is invoked by an effect of giant van Hove singularity. However the relative cooling power (RCP) is very close in DMFT and MFA for the same model parameters and goes down upon U increase.

Raman spectroscopic analysis of paddy rice infected by three pests and diseases common in Northeast Asia

Pests and diseases seriously affect the yield and economic benefits of growing rice, and the key to inhibiting rice’s pathogenesis is to find early identification of rice infection. The characteristic Raman spectrum of healthy leaves, and leaves infected with rice blast, paddy rice bakanae and infected by Chilo suppressalis (Walker) were tested by TriVista555CRS laser Raman spectrometer (900cm−1–1700cm−1). At the same integration time, compared with healthy plants, the Raman peak of infected plants not only changed significantly, but also the signal intensity decreased. The results show that there are clear Raman peaks at the three characteristic wavenumbers of 1002.87cm−1, 1156.5cm−1 and 1522.36cm−1. Especially in the leaves of rice blast, it was found that the degree of fungal infection affects the peak width at half height of the characteristic peak. The research shows that Raman spectroscopy provides an effective method for the early detection of rice pests and diseases which may have economic benefits.

Separation technique based on electrophoresis, chromatography and magnetism phenomena: the migration time and peak broadening

Magnetic nanoparticles incorporated into the surface layer of a capillary column can produce an electromagnetic field upon applying the electric field, which would affect the separation of charged analytes. The main peak parameters, migration time and width at half height were evaluated, which are important to development of a novel separation technique based on the electrophoresis, chromatography, and magnetism.

Reinforced high-strength engineered cementitious composite (ECC) columns under eccentric compression: Experiment and theoretical model

Engineered cementitious composites (ECC) with a tensile rupture strain larger than 3%, has won itself wide attention at the material level. To further investigate its performance at the structural component level, a series of reinforced ECC (R/ECC) columns with the cross-section dimensions of 120 mm × 120 mm were tested under large eccentric compressive loading at the eccentricity of 80 mm. One reinforced concrete (RC) column was also fabricated for reference. The compressive strengths of both ECC and concrete were controlled at 60 MPa. The displacement at half height point, the strains of longitudinal bars and the crack patterns of columns were monitored. The experimental results showed that the peak load of the plain ECC column approached 50% of the value of the RC column with a reinforcement ratio of 4.3% (RC-4.3%). The peak load of R/ECC column was found to gain an increase of 35.2% compared to the RC column with the same reinforcement ratio. The multiple-crack patterns were fully developed along the height of the column. An analytical model was proposed for the load-bearing capacity of R/ECC columns under large eccentric compression, and was validated by the experimental results. Finally, parametric analyses showed that the peak load of plain ECC-90 column (i.e., compressive strength = 90 MPa) was similar to the value of RC-4.3%, while the peak load of plain ECC-120 column (i.e., compressive strength = 120 MPa) exceeded that of RC column, implying that high-strength ECC could be applied to completely replace the steel bars in columns.

Staircase Modulation with Different Staircase Wave Generation Techniques for Multilevel Inverters

Multilevel inverters are widely used in industrial areas because it is suitable for medium and high power application. In the switching control of most of the multilevel inverters, sinusoidal PWM is most commonly used. But the difficulty faced in sinusoidal PWM is, the need of pure sinusoidal signal in the control. So, in order to avoid this limitation, another modulation known as the staircase modulation can be used in the control of MLI. This paper discusses about various staircase reference wave generation methods such as half height (HH) method, Half Equal Phase (HEP) method and Feed Forward (FF) method. The performance analysis of different staircase waves in control of MLI is carried out with an eleven level cascaded H Bridge Multilevel inverter using phase shift carrier modulation. The objective of analysis to find a method of staircase reference wave generation with lesser THD. The performance of 11 level CHB with different staircase reference signal is analyzed in terms of THD using Matlab/Simulink software.

Simulation of peak position and response profiles in comprehensive two-dimensional gas chromatography

Approaches to simulate peak time and intensity profiles of compounds in comprehensive two dimensional gas chromatography (GC × GC) were developed, and which are demonstrated for separation of a mixture of saturated and unsaturated fatty acid methyl esters (FAME) using a range of column sets. The simulation of first and second dimension time (1tR and 2tR) of FAME relies on use of a Gibbs energy additivity approach to correlate with the structures of FAME. First and second dimension peak standard deviations (1σ and 2σ) of the compounds were further calculated from the 1tR and 2tR data according to the plate height concept which provided good agreement between the predicted and experimental peak widths at half height in one dimension GC (1DGC) with an overall R2 of 0.9628. The effect of 1σ distortion caused by the modulation process was also taken into account in the peak width simulation where the simulated 1σ data were rounded up to multiples of the scale of modulation period (PM). Two dimension Gaussian equations were then used to generate GC × GC results (2D contour plots) from simulated 1tR, 2tR, 1σ and 2σ data for FAME separation on different column sets employing ionic liquid and conventional columns. Good overall correlations between experimental and simulated 1tR and 2tR were obtained with R2 of 0.9951 and 0.9802, respectively, and the simulated 2D contour plots were an acceptable match with the experimental results.

Spectroscopic, dielectric properties and phase transition of Bis (diethylammonium) hexachlorido stannate(IV)

The [C4H10NH2]2SnCl6 compound is characterized by using the X-ray powder analysis, thermogravimetric analysis, differential scanning calorimetry analysis, 13C and 119Sn (CP/MAS NMR) analysis, vibrational spectroscopy and complex impedance spectroscopic data. The results show that this compound exhibits a phase transition at 326 K which was characterized by differential scanning calorimetry (DSC), X-rays powder diffraction, Raman spectroscopy and dielectric measurements. The most important changes are observed for four lines at 3207 cm−1, 3056 cm−1, 3000 cm−1 and 1538 cm−1 (at room temperature) issued from asymmetric and symmetric stretching vibrations of νs(NH2), νs(NH2), νas(NH2) and νδ(NH2) band, respectively. The assignment of the observed IR and Raman lines was performed by comparison with the homologous compounds. Dielectric data were analyzed using complex permittivity ε* and complex electrical modulus M* for the sample at various temperatures. The Z′ and Z” versus frequency plots are well fitted to an equivalent circuit model. The analysis of Nyquist plots are well fitted to an equivalent circuit consisting of series of combination of grains and grain boundary elements. The AC conductivity was studied using the following equation: σAC(ω)=σs1+τ2ω2+σ∞τ2ω21+τ2ω2+Aωs. The conductivity follows the Arrhenius relation. Hopping frequency was determined and activation energy of hopping is almost equal to the activation energy of conduction. The temperature dependence of the power law exponent s and a.c conductivity σac is reasonably interpreted by the quantum mechanical tunneling (QMT) and the barrier hopping (CBH) model. The modulus plot can be characterized by full width at half height or in terms of a non-experiential decay function ϕ(t) = exp(−t/τ)β.

On the Hydration of Heavy Rare Earth Ions: Ho3+, Er3+, Tm3+, Yb3+ and Lu3+-A Raman Study.

Raman spectra of aqueous Ho3+, Er3+, Tm3+, Yb3+, and Lu3+-perchlorate solutions were measured over a large wavenumber range from 50–4180 cm−1. In the low wavenumber range (terahertz region), strongly polarized Raman bands were detected at 387 cm−1, 389 cm−1, 391 cm−1, 394 cm−1, and 396 cm−1, respectively, which are fairly broad (full widths at half height at ~52 cm−1). These isotropic Raman bands were assigned to the breathing modes, ν1 Ln–O of the heavy rare earth (HRE) octaaqua ions, [Ln(H2O)8]3+. The strong polarization of these bands (depolarization degree ~0) reveals their totally symmetric character. The vibrational isotope effect was measured in Yb(ClO4)3 solutions in H2O and D2O and the shift of the ν1 mode in changing from H2O to D2O further supports the character of the band. The Ln–O bond distances of these HRE ions (Ho3+, Er3+, Tm3+, Yb3+, and Lu3+) follow the order of Ho–O > Er–O > Tm–O > Yb–O > Lu–O which correlates inversely with the band positions of the breathing modes of their corresponding octaaqua ions [Ln(OH2)8]3+. Furthermore, the force constants, kLn–O, were calculated for these symmetric stretching modes. Ytterbium perchlorate solutions were measured over a broad concentration range, from 0.240 mol·L−1 to 2.423 mol·L−1, and it was shown that with increasing solute concentration outer-sphere ion pairs and contact ion pairs were formed. At the dilute solution state (~0.3 mol·L−1), the fully hydrated ions [Yb(H2O)8]3+ exist, while at higher concentrations (CT > 2 mol·L−1), ion pairs are formed. The concentration behavior of Yb(ClO4)3 (aq) shows similar behavior to the one observed for La(ClO4)3(aq), Ce(ClO4)3(aq) and Lu(ClO4)3(aq) solutions. In ytterbium chloride solutions in water and heavy water, representative for the behavior of the other HRE ions, 1:1 chloro-complex formation was detected over the concentration range from 0.422–3.224 mol·L−1. The 1:1 chloro-complex in YbCl3(aq) is very weak, diminishing rapidly with dilution and vanishing at a concentration < 0.4 mol·L−1.

XPS Analysis of the Oxide Films Formed on Non-Charged and Hydrogen-Charged 316L SS in Deaerated High Temperature Water

Austenitic stainless steel components have been used in pressurized water reactors (PWRs) coolants. These austenitic stainless steels may absorb hydrogen from either the dissociation of dissolved hydrogen in PWR primary water or the corrosion processes at the steel surfaces during the immersion in PWR primary water. It is necessary to investigate the effect of hydrogen in alloys on the oxidation and resultant environmental degradation processes in high temperature water environments. In the present study, the oxide films formed in deaerated PWR primary water at 300℃on a cold worked 316L (316LCW) stainless steel with or without prior hydrogen-charging were characterized. Hydrogen-charging of 316LCW was performed by cathodic charging in sulfuric acid solution containing thiourea at room temperature. Prior to the immersion tests, the Immersion tests were performed in a 2-L Ti-autoclave with solution deaerated by purging N2 gas before heating to test temperature. The oxide films formed on 316LCW and hydrogen-charged 316L CW (316LCW-H) specimens after exposure to deaerated PWR primary water at 300 oC for168 h were observed. The XPS depth profiles of the oxide films formed on 316LCW and 316LCW-H specimens after exposed to simulated PWR primary water are compared. The thickness of the oxide film was estimated from the half height of oxygen concentration and the sputtering rate (0.1 nm/s), for determining the thickness of the oxide film that was about 180 nm on 316LCW and about 250 nm on 316LCW-H. The oxide films formed on both 316LCW and 316LCW-H were enriched in Fe and Ni in the outer layer, and enriched in Cr in the inner part of the oxide film. The Cr content in the inner oxide layer formed on 316LCW-H specimen was lower than that on 316LCW specimen. Figure 1

Flow Characteristics of a Rich-Quench-Lean Combustor-Combined Low-Emission and High-Temperature Rise Combustion

To determine the flow field structure and flow characteristics of a rich-quench-lean (RQL) combustor-combined low-emission and high-temperature rise combustion, a two-dimensional PIV technology was used to evaluate the effect of aerodynamic and structural parameters on the flow field and flow characteristics of the combustor. The variation in the total pressure loss of the combustor has little effect on the flow field structure of the combustor. However, the variation in the parameters of primary holes significantly affects the structure of the central recirculation zone, the distribution of local recirculation zones in the rich-burn zone and quenching zone, and the average residence time in the quenching zone. On the plane that passes through the center of the primary hole, the variations in the array mode and diameter of primary holes would form entrainment vortexes with different characteristics, thus affecting the position and flow state of local recirculation in the rich-burn zone and the local structure of the central recirculation zone. As the rotational direction of local recirculation coincides with that of the main air flow in the primary zone, the local center recirculation is intensified. In contrast, it is weakened. As the primary holes are located at half height (H/2) of the combustor, the residence time of air flow at the quenching zone can be shortened by 65% through using the staggered structure of primary holes and increasing the momentum of the partial single-hole jet. The quick-mixing process in the quenching zone is not beneficial to increase the number of primary holes and decrease the momentum of the single-hole jet.

Orientation, distribution, and deformation of inertial flexible fibers in turbulent channel flow

In this paper, we investigate the dynamics of flexible fibers in turbulent channel flow. Fibers are longer than the Kolmogorov length scale of the carrier flow, and their velocity relative to the surrounding fluid is non-negligible. Our aim is to examine the effect of local shear and turbulence anisotropy on the translational and rotational behavior of the fibers, considering different elongation (parameterized by the aspect ratio, $$\lambda $$ ) and inertia (parameterized by the Stokes number, St). To these aims, we use a Eulerian–Lagrangian approach based on direct numerical simulation of turbulence in the dilute regime. Fibers are modeled as chains of sub-Kolmogorov rods (referred to as elements hereinafter) connected through ball-and-socket joints that enable bending and twisting under the action of the local fluid velocity gradients. Velocity, orientation, and concentration statistics, extracted from simulations at shear Reynolds number $$Re_{\tau }=150$$ (based on the channel half height), are presented to give insights into the complex fiber–turbulence interactions that arise when non-sphericity and deformability add to inertial bias. These statistical observables are examined at varying aspect ratios (namely $$\lambda _{r}=l_{r}/a=2$$ and 5, with $$l_{r}$$ the semi-length of each rod-like element r composing the fiber and a its cross-sectional radius) and varying fiber inertia (considering values of the element Stokes number, $$St_{r}=1$$ , 5, 30). To highlight the effect of flexibility, statistics are compared with those obtained for fibers of equal mass that translate and rotate as rigid bodies relative to the surrounding fluid. Flexible fibers exhibit a stronger tendency to accumulate in the very-near-wall region, where they appear to be trapped by the same inertia-driven mechanisms that govern the preferential concentration of spherical particles and rigid fibers in bounded flows. In such region, the bending of flexible fibers increases as inertia decreases, and fiber deformation appears to be controlled by mean shear and turbulent Reynolds stresses. Preferential segregation into low-speed streaks and preferential orientation in the mean flow direction is also observed.

Rotating Ag-Fe3O4-Au Nanograin by Optical Torque with a Monochromatic Light Beam

Optical torques of asymmetrical Ag–Fe3O4–Au nanograins were investigated by the method of discrete dipole approximation (DDA). The results show that surface plasmon resonance (SPR) causes the optical torques which can keep the nanograins rotating clockwise or counterclockwise. When the power density of optical radiation is I = 109 W/m2, the angular velocities of the hybrid sphere and cube heterotrimers can reach to about 104 rad/s in the ranges of 360–374 nm and 403–426 nm, which is ten times larger than that of Brownian rotation. The peak widths at half height of angular velocity curves for two kinds of grains are in the ranges of 31–47 nm and 54–70 nm, respectively. When light radiation force offers a regular driving force, such grains can serve as potential nanoscale optical wrench or microscopic mixers. In addition, the influences of Brownian rotation and photophoresis were discussed.

Computed tomography scan morphometric study of adolescent vertebral laminae: From three-dimensional reconstruction to laminar hook

INTRODUCTION: The authors report a descriptive analysis of spine computed tomography (CT) scan to describe the anatomy of the laminae of T2 and T3 vertebrae. The aim of the study was to establish reference data in the adolescent population. These data could be useful to improve the effectiveness of laminar hooks. Hook-claw anchorage has been considered as one of the best choices in terms of safety and durability in the spine surgery. MATERIALS AND METHODS: We systematically reviewed CT scans of 14–16-year-old healthy individuals who underwent CT scans in other indications than scoliosis during a 2-year period. Patients with spine, chest, or bone disease were excluded. The Risser sign was ≥ 2. CT scan data were converted into a three-dimensional reconstruction. RESULTS: Seven hundred and fifty measures were collected from 30 CT scans matching with the inclusion/exclusion criteria. The mean age was 15-years old. Gender was mixed. Mean T2 lamina's upper half height was 8.9 mm (8.2–9.6) corresponding to a thickness of 7.1 mm (6.6–7.7). Mean T3 lamina's lower half height was 9.0 mm (6.9–10.4) corresponding to a thickness of 7.3 mm (6.8 a 7.9). DISCUSSION: No previous study reported these data in adolescents. Laminae in adolescents appeared to be slightly oversized in this study relative to the previous reports in adults. It seems that the intracanal part length of the hook and depth of the gorge should be adapted in order to improve fitting of the implant with laminae. CONCLUSION: This study brings new data in the knowledge of anatomical characteristics of the vertebras that should help to improve safety and stability of implants as laminar hook and hook claw.