Original Thickness Research Articles

Radial and axial stiffness of superconducting bearings based on YBCO single-domain bulks processed with artificial holes

Superconducting magnetic bearings are becoming more widespread, due to the unique properties they provide. Their efficiency is unparallel, there are no issues such as contact, friction, and wear. They require low or minimal maintenance, no lubrication and they work under extreme conditions (cryogenic temperatures, high vacuum). In this contribution, the influence of geometric properties of superconducting bulks on the performance of superconducting bearings was studied. The main focus was paid to load capacity, radial and axial stiffnesses. Two samples with a significantly higher aspect ratio compared to conventional bulks were prepared. One of these samples was synthesized with artificially created holes. The samples were prepared using top-seeded melt-growth process with an additional source of a liquid phase in the form of an underlaying pad. The original thickness of 16 mm of the samples with a diameter of 28 mm was repeatedly ground down. Levitation force and trapped field were measured after each grinding step. Using this approach, the dependence of properties of the bulks on their thickness, scaling of these properties with thickness and the influence that artificial holes can make on the properties of finished single domain bulks were studied. The maximum levitation force was greatly improved for bulks with thicknesses of 2–6 mm. Such data is of the utmost importance in the field of superconducting YBCO single domain bulk ceramics, as it allows for better understanding and further improvement of both the manufacturing process and real-world applications of these materials.

Pavement Thickness Design Charts Derived from Rut Depth Models Developed for Foamed and Emulsified Sulfur Asphalt Soil Mixes

This paper presents the utilization of models already derived from results of dynamic triaxial tests performed on marginal soils (marl and sabkha) stabilized with foamed and emulsified sulfur asphalt. These stabilized materials are considered to be used as base layers in a pavement structure. Permanent strain relations obtained from dynamic triaxial testing were used in VESYS model to predict rutting performance and magnitude. Predicted rutting performance and magnitude were close to the actual rut depth measured during wheel tracking tests to validate the models. These models developed for rutting prediction were used in VESYS 5 W software to forecast the life or the axle passes needed to attain a rut depth delineating the end of life for a variety of pavement thicknesses, and the subgrade soils to create original pavement thickness design charts. Most of the subgrade soils in Saudi Arabia as well as the coastal areas of the Arabian Gulf are usually marl, sabkha or dune sand soils.

Atomic layer deposition-induced integration of N-doped carbon particles on carbon foam for flexible supercapacitor

Flexible devices have attracted abundant attention in energy storage systems. In this paper, we presented a novel approach for fabricating flexible supercapacitor based on metal organic frameworks-derived material. In this approach, a uniform zeolitic imidazolate frameworks-8 layer with a high mass loading was deposited on a flexible carbon foam (CF) skeleton efficiently by the induction of a uniform ZnO nanomembrane prepared via an atomic layer deposition technique. A flexible N-doped carbon particle-carbon foam (N-CP-CF) composite with a hierarchically porous structure and a large specific surface area (i.e., 538 m2 g−1) was obtained in a subsequent pyrolysis process. The resultant materials have the excellent electrochemical performance (i.e., a high specific capacitance of 300 F g−1 and a high energy density of 20.8 W h kg−1). The N-CP-CF composite can provide a stable capacitance (i.e., 250 F g−1) and an energy density (i.e., 17.36 W h kg−1) under large deformation (25% of original thickness). This work could propose a promising strategy in fabrication of flexible electrode with a large potential towards energy storage applications in the future.

Design of Ultrathin Current Collectors via Cyclically Plastic Yield for Fabrication of High Capacity Lithium Ion Batteries

In this manuscript a strategy is developed for the design of ultrathin current collectors in the fabrication of high capacity lithium ion batteries. A lithiation-delithiation induced elastoplasticity analysis is performed to determine the thickness limit of a current collector for a given cycle life. The calculation results show that both the plastic yield and cyclical plastic deformation of current collectors are beneficial to not only the battery capacity due to a less inactive packing but also the cyclic performance because of lower stresses in the active layers. There are three possible elastoplastic behaviors for current collectors of different thicknesses, i.e. pure elastic, plastic shakedown and cyclic plasticity. Cyclic plasticity is preferred because it occurs in the thinnest current collector where the stress in the active layer is found to be the lowest. Furthermore, a fatigue analysis is carried out to determine the relation between current collector thickness and cycle life. Finally, by using this design method to evaluate three commercial 18650 lithium ion batteries reported in literature, it is found that all the examined battery structures can be optimized using thinner current collectors; in some cases, the thickness of these collectors could be even reduced to half their original thickness.

A novel electro-active bushing based on dielectric elastomer and circular double-V auxetic structure

A novel electro-active bushing (EAB) design is proposed based on the unique physical properties of dielectric elastomers. A dielectric elastomer is applied as the tendon layer to a circular two-dimensional double-V auxetic structure. When load and voltage excitation vary, mechanical performance and dimensions of dielectric elastomers change, which empowers EAB to realize an electrostrictive phenomenon and real-time variable stiffness under different voltages. An EAB structure can endure mechanical loads along all directions in a cross-sectional plane, which is more practical than our previous design which can only bear loads along one direction. A theoretical electromechanical model of an EAB unit cell was proposed based on the physics theory of dielectric elastomers. The influences of unit cell parameters on electromechanical responses were researched. Moreover, an EAB prototype was fabricated via the 3D printing method. The experiments using EAB prototype applied 3M VHB 4910 and 3M VHB 9473 acrylic membranes prestretched by 200% and 300%, respectively, were conducted. The results indicated that the electrostrictive displacement increases as the load increases, and the stiffness decreases with the rise in voltage. Greater stiffness is obtained by higher original thickness and prestretch rates, but the electrostrictive displacement and stiffness variation under high excitation was dramatically affected.

Alternative methods for calculating compaction in sedimentary basins

Abstract Subsidence analysis is an important technique in the study of sedimentary basins but the effects of compaction must be “backstripped”. The compaction of sediments is also of importance for petroleum and water reservoir research with very important economic derivations. Most methods for calculating compaction are based on empirically derived porosity-depth relationships from a variety of known sediment types. The challenge of this paper is to apply alternative methods for calculating compaction in sedimentary basins based on: physical calculation with elastic by Steinbrenner, oedometric and change of the specific weight of the sediment methods; and use of Loadcap software. The Triassic to Lower Miocene 3025 m thick succession of Sierra Espuna (SE Spain) is used as case study for the calculations. In this succession former mineralogical studies and apatite fission-track suggested an original thickness between 4 and 6 km. The validity of each one of the proposed methods is discussed, as well as, compared for the whole succession compaction but also separately for hard vs soft sediments and for thick vs thin beds. The compaction values obtained with the alternative methods are similar to those resulting with the lower-limit curves of the porosity-depth change method. The new methods have provided values slightly higher than 4 km for the whole original thickness using the geotechnical software and the change of the sediments specific weigh methods; meanwhile values below 4 km for other methods. So, in our opinion, the geotechnical software and the change of the specific weight of the sediment methods are compatible with mineralogical constraints and also, the input data are usually better known and easier to determinate. Otherwise, the elastic method seems only accurate for soft sediments; meanwhile the oedometric method is highly influenced by the thickness of the considered beds.

Mechanics of double-sheet die-less shear spinning: a novel potential method for wall thickness control in spinning process

Die-less spinning has high flexibility in aeronautics, aerospace vehicles and other manufacturing fields; however, the wall thickness of the workpiece is hard to control in die-less shear spinning. A flexible control method of wall thickness distributions on the truncated cone shape is attempted using double-sheet shear spinning. The fundamental approach entails the adjustment of original thickness during forming. In double-sheet die-less shear spinning, two aluminum disk blanks arranged concentrically are formed for truncated cone. The cover thicknesses of the spun workpieces are smaller than the value that conforms to the sine law using the same blank thickness. The wall thicknesses of base spun workpieces are bigger than the sine law value under the same circumstances. The theoretical mechanics analysis of the double-sheet shear spinning process is carried out through mechanics and finite element analysis.

Evolution of a structural basin: Numerical modelling applied to the Dehdasht Basin, Central Zagros, Iran

The Dehdasht Basin, a small structural basin located in the southeast of the Dezful Embayment in the Zagros fold-and-thrust belt, has a complex tectonic structure characterized by both compressional and halokinetic features. 2D numerical models are used to test how geometrical and rheological parameters affected the Miocene-Pliocene evolution of this deep basin. The analysed parameters include rates of syntectonic sedimentation and erosion, thickness and viscosity of the lower detachment (Hormuz salt) and of the upper detachment (Gachsaran evaporites) developing diapiric salt walls, salt extrusions and minibasins-growth synclines that characterize the internal structure of the Dehdasht Basin. Assuming reasonable dimensions and rheologies (0.5 km Hormuz basal detachment with moderate viscosity of 1019 Pa·s, and Gachsaran upper detachment with a minimum original thickness of 1.5 km and viscosity between 5 · 1018 and 1019 Pa·s), our models reveals that an almost intermediate ratio between the rates of surface processes and deformation well approximate the geological and geophysical observations. A local decrease in the thickness of the Hormuz salt below the Dehdasht Basin with respect to surrounding regions was of great importance for its structural evolution. We suggest that the large volume of Gachsaran evaporites presently filling the basin was partly due to their gravitational flow from the emerging surrounding anticlines into the basin. The numerical experiments also demonstrate that in a compressional setting, shortening is the main factor for the rapid initial growth of the diapirs, although, with increasing syntectonic sedimentation the effect of shortening diminishes.

Stress-induced remodelling of the mitral valve: a model for leaflet thickening and superimposed tissue formation in mitral valve disease.

In mitral valve prolapse (MVP), leaflet thickening has recently been suggested to be due, in addition to a myxomatous degeneration, to the presence of a superimposed tissue (SIT), defined as an additional fibrous layer on top of the original leaflet. The mechanisms of SIT formation are currently unknown. We hypothesized that SIT formation would result from excessive leaflet stress and we used a unique ex vivo model to assess the correlation between leaflet remodelling and the type and location of mechanical stress and to elucidate the mechanisms underlying SIT formation. Human diseased mitral valves (MVs; n = 21) were histologically analysed for SIT formation and original leaflet thickening. The SIT comprised of various compositions of extracellular matrix and could reach more than 50% of total leaflet thickness. Original leaflet and SIT thickness did not show significant correlation (r = -0.27, P = 0.23), suggesting different regulatory mechanisms. To study the role of the mechanical environment on MV remodelling, mouse MV were cultured in their natural position in the heart and subjected to various haemodynamic conditions representing specific phases of the cardiac cycle and the MVP configuration. SIT formation was induced in the ex vivo model, mostly present on the atrial side, and clearly dependent on the duration, type, and extent of mechanical stress. Specific stainings and lineage tracing experiments showed that SIT comprises of macrophages and myofibroblasts and is associated with the activation of the transforming growth factor-beta and bone morphogenetic protein signalling pathways. Migration of valvular interstitial cells and macrophages through breakages of the endothelial cell lining contributed to SIT formation. Mechanical stresses induce specific cellular and molecular changes in the MV that result in SIT formation. These observations provide the first insights in the mechanism of SIT formation and represent an initial step to identify potential novel and early treatment for MVP.

Microstructure and mechanical properties of cryorolled Al–6Zn–3Mg–2Cu–0.5Sc alloy

Abstract Al–6Zn–3Mg–2Cu–0.5Sc alloy with 85% rolling reduction from the original thickness at room and cryogenic temperatures leads to high tensile strength and higher dislocation density for the cryorolled (CR) (−80 °C) sample. Microstructural investigation and their properties on mechanical behaviour of Al–6Zn–3Mg–2Cu–0.5Sc alloy were noted in detail during rolling as-cast, room temperature rolling (RTR) and cryorolling (−80 °C) conditions. The CR (−80 °C) sample revealed greater work hardening value than the as-cast alloy, due to the effect of CR and the presence of Al3CuMg precipitates. The Hierarchical Grain Size Distribution (HGSD) reported in cryorolled samples via Electron Back Scattered Diffraction (EBSD) studies, and it leads to a high strength of 537 MPa and 17% ductility in CR (−80 °C) samples. Transmission electron microscope (TEM) studies revealed that the high dense dislocations and nano sized intermetallic compounds are equally distributed alongside the matrix in the CR (−80 °C) among the rolled samples. Al–6Zn–3Mg–2Cu–0.5Sc alloy showed improved mechanical properties during various rolling conditions.

Effects of Ti foil thickness on microstructures and mechanical properties of in situ synthesized micro-laminated TiC/Ti composites

In situ micro-laminated TiC/Ti composites were fabricated by hot-pressing alternatively stacked graphite and Ti foils. With increase in the original thickness of Ti foils, the thickness (i.e., volume fraction) of Ti layers in the composites increased, whereas the thickness of TiC layers remained relatively constant. The flexural strength and fracture toughness of composites also increased with increase in the original thickness of Ti, and the maximum fracture toughness was 35.27 MPa*m1/2. Nevertheless, the compressive strength of composites decreased with increase in the original thickness of Ti along both the perpendicular-to-lamellar direction and the parallel-to-lamellar direction. However, different failure modes and much higher compressive strength along the parallel-to-lamellar direction than along the perpendicular-to-lamellar direction highlight the anisotropy of the composites in compressive properties. By tailoring the original thickness of Ti foils, the mechanical properties of the laminated TiC/Ti composites can be controlled without changing the phase structure, chemical composition, and the thickness of the brittle TiC layers.

Controlled size reduction and its underlying mechanism to form solid-state nanopores via electron beam induced carbon deposition

Solid-state nanopores have drawn considerable attention for their potential applications in DNA sequencing and nanoparticle analysis. However, fabrication of nanopores, especially those of diameter below 30 nm, requires sophisticated techniques. Here, a versatile method to controllably reduce the diameter of prefabricated large-size pores down to sub-30 nm without greatly increasing the effective pore depth from the original membrane thickness is shown. This method exploits carbon deposition achieved via hydrocarbon evaporation, induced by an incident beam of electrons, and subsequent dissociation of hydrocarbon to solid carbon deposits. The carbon deposition employs a conventional scanning electron microscope equipped with direct visual feedback, along with a stable hydrocarbon source nearby the sample. This work systematically studies how electron beam accelerating voltage, imaging magnification, initial pore size and membrane composition affect the process of pore size reduction. Secondary electrons generated in the membrane material are confirmed to be the main cause of the dissociation of hydrocarbon. Thicker carbon deposited on one side than on the other of the membrane results in an asymmetric nanopore shape and a rectifying ionic transport. A physico-phenomenological model combined with Monte Carlo simulations is proposed to account for the observed carbon deposition behaviors.

Does navigated patellar resurfacing in total knee arthroplasty result in proper bone cut, motion and clinical outcomes?

BackgroundIn total knee arthroplasty with patellar resurfacing, patellar bone preparation, component positioning and motion assessments are still not navigated. Only femoral/tibial component positioning is supported by computer-assistance. The aim of this study was to verify, in-vivo, whether knee surgical navigation extended to patellar resurfacing, by original instrumentation and procedures for patellar-based tracking, could achieve accurate patella preparation in terms of original thickness restoration, bone cut orientation, and normal knee motion. MethodsAn additional navigation system for patellar data acquisition was used together with a standard navigation system for total knee arthroplasty in 20 patients. This supported the surgeon for patellar resurfacing via measurement of removed bone thickness, three-dimensional patellar cut orientations, and patello-femoral motion. Radiological and clinical examinations at 6 and 24-month follow-up were also performed. FindingsThe medio-lateral patellar-bone cut orientation was respectively 0.5° (standard deviation: 3.0°) and 1.4° (1.7°) lateral tilt, as measured via navigation and post-operatively on the Merchant x-ray view. The cranio-caudal orientation was 3.8° (7.2°) of flexion. The thickness variation between patellar pre- and post-implantation was 0.2 (1.3) mm. Immediately after implantation, patello-femoral as well as tibio-femoral kinematics was within the normality. Good radiological and clinical examinations at 6 and 24-month follow-up were also observed. InterpretationFor the first time, the effect of patellar navigation for its resurfacing was assessed in-vivo during surgery, with very good results for thickness restoration, proper cut orientation, and normal knee motion. These results support the introduction of patella-related navigation-based surgical procedures for computer-assisted total knee arthroplasty.

Modified Densification Process for Increasing Strength Properties of Pine and Gmelina Wood from Community Forests

Densification is a process for improving the strength properties of wood from the felling of young trees, which is a common harvest practice in community forests. A series of experiments was conducted to refine the process with particular regard to the determination of suitable pretreatment and treatment conditions. Samples of pine and gmelina measuring 23 cm (L) × 20 cm (W) × 2 cm (T) underwent pretreatment through immersion in a 1:1 CH3COOH-H2O2 solution at concentrations of 15%, 20%, and 30%. Samples pretreated with the 20% solution showed the greatest improvement in strength; further experiments were conducted to determine the optimum treatment conditions in terms of temperature and duration following immersion. Test samples with the same dimensions as those in the pretreatment experiment were soaked in a 1:1 20% CH3COOH-H2O2 solution and warmed in a water bath. The test samples were then individually hot pressed to the target thickness, which was 30% less than the original thickness and held at 150°C or 170°C for 15 or 30 minutes. The treated samples were cut for an analysis of their density, recovery of set, and bending strength. Pine and gmelina exhibited the best characteristics after treatment at 150°C for 30 and 15 minutes, respectively. The results suggest that the modified densification process had increased the bending strength of the wood, but the temperature and duration of treatment must be carefully considered for different wood species.

Performance improvement of a vanadium redox flow battery with asymmetric electrode designs

A two-dimensional transient model with considering vanadium ions crossover and incorporating the impact of electrode compression was presented for a vanadium redox flow battery (VRFB). Emphasis is located on examining the effects of the proposed asymmetric electrode structure designs on capacity degradation, vanadium ions crossover, the charge-discharge voltages and efficiency of the VRFB during long-time cycling. It was indicated that for asymmetric electrode compression with same original thickness, the capacity decay can be effectively alleviated with increasing the positive compression ratio, due to the fact that the electrolyte crossover is balanced by adjusting the convection flux during a charge-discharge cycle. The charge-discharge performance and energy efficiency of the VRFB can also be simultaneously boosted resulting from the reduced contact resistance and increased electrolyte flow velocity in the compressed positive electrode. Also, it was found that with appropriate design of asymmetric original thickness of uncompressed electrode, the capacity decay can be avoided and battery charge-discharge performance can be improved. This study will provide fundamental information for optimizing the asymmetric electrode structures such that the overall battery performance during long-time cycling can be enhanced.

Study on Icing Prediction of Power Transmission Lines Based on Ensemble Empirical Mode Decomposition and Feature Selection Optimized Extreme Learning Machine

The ice coating on the transmission line is extremely destructive to the safe operation of the power grid. Under natural conditions, the thickness of ice coating on the transmission line shows a nonlinear growth trend and many influencing factors increase the difficulty of forecasting. Therefore, a hybrid model was proposed in this paper, which mixed Ensemble Empirical Mode Decomposition (EEMD), Random Forest (RF) and Chaotic Grey Wolf Optimization-Extreme Learning Machine (CGWO-ELM) algorithms to predict short-term ice thickness. Firstly, the Ensemble Profit Mode Decomposition model was introduced to decompose the original ice thickness data into components representing different wave characteristics and to eliminate irregular components. In order to verify the accuracy of the model, two transmission lines in ‘hunan’ province were selected for case study. Then the reserved components were modeled one by one, building the random forest feature selection algorithm and Partial Autocorrelation Function (PACF) to extract the feature input of the model. At last, a component prediction model of ice thickness based on feature selection and CGWO-ELM was established for prediction. Simulation results show that the model proposed in this paper not only has good prediction performance, but also can greatly improve the accuracy of ice thickness prediction by selecting input terminal according to RF characteristics.

Deformable plate tectonic models of the southern North Atlantic

Significant, poly-phase deformation occurred prior to, simultaneous with, and after the opening of the North Atlantic Ocean. Understanding this deformation history is essential for understanding the regional development and the mechanisms controlling rifting and subsequent failure or breakup. Here, we primarily use published constraints to construct deformable plate tectonic models for the southern North Atlantic from 200 Ma to present using GPlates. The aim of this work is to test both the capability of the GPlates deformable modelling approach and the reliability of published plate reconstructions. Overall, modelled crustal thickness values at 0 Ma produced from the deformable models show general, regional-scale, similarities with values derived from the inversion of gravity data for crustal thickness. However, the deformable models typically underestimate thinning in marginal basins and overestimate crustal thickness in continental fragments compared to values from gravity inversion. This is possibly due to: 1) thinning occurring earlier than the 200 Ma start time modelled, 2) variations in the original crustal thickness, 3) depth-dependent stretching, 4) rigid blocks undergoing some degree of thinning, and 5) variations in the mesh density of the models. The results demonstrate that inclusion of micro-continental fragments, and locally defined limits of continental crust, generally produce results more akin to observations. One exception is the Grand Banks where global GPlates models produce more realistic deformation, likely due to the inclusion of the exhumed domains continent-ward of the transition zone boundary. Results also indicate that Flemish Cap rotation is required to provide a reasonable fit between North America and Iberia, with the palaeo-position of the Flemish Cap likely to be the proto-Orphan sub-basins. Moreover, the East and West Orphan sub-basins formed separately due to the respective rotations of the Flemish Cap and the Orphan Knoll, which was likely associated with other continental fragments that subsequently contributed to the thicker crust forming the boundary between the East and West Orphan basins. The results also suggest a link between tectonic and magmatic processes. For example, the inclusion of an Orphan Knoll micro-continental block results in greater extension (higher beta factors) in the northern West Orphan Basin near the termination of the Charlie-Gibbs Fracture Zone, and the site of the Charlie-Gibbs Volcanic Province (CGVP). Thus, we infer that the CGVP was likely influenced by plate tectonic processes through the concentration of strain resulting from interaction in proximity to the transform system. Finally, marginal basins that were considered to be conjugate and thus related, may only appear conjugate through later rotation of micro-continental blocks, and thus their genesis is not directly related.

Cultural differences and neural correlates of cognitive insight in schizophrenia

Cognitive insight refers to a person's ability to examine their psychotic experiences and the inferences they draw from these experiences. Several studies suggest that cultural factors influence cognitive insight and the processes involved therein; a few studies have suggested differences between Western and Asian societies. However, there are no studies on cognitive insight and its neural correlates in non-Western populations. Hence, we examined factor structure of Beck's cognitive insight scale (BCIS) in a large sample of patients with schizophrenia (SCZ) and healthy volunteers (HV) from India and assessed the relationship between cortical thickness and cognitive insight. We recruited 240 participants (SCZ-140; HV-100). Of these, 58 participants (SCZ-33; HV-25) underwent magnetic resonance imaging. We found a three-factor structure for BCIS which is different from the original two factor structure; self-reflection (SR) of original two-factor structure was sub-divided into– SR1, introspection and SR2, openness to feedback. There was a significant difference between HV and SCZ in the new factors, SR1 and SR2 but not in the original SR factor. Difference was also seen on MRI analysis; while there was a significant positive correlation between original SR factor and thickness of right posterior cingulate cortex, SR2 was positively correlated with thickness of left ventrolateral prefrontal cortex. The difference in factor structure in Indian participants and their distinct neural correlates point to cultural differences in cognitive insight. While in western societies the constructs of introspection and openness to feedback might integrate, they might be separate entities in Asian population.

Assessment on tunnel lining to ensure stability in soft ground

Soft ground tunnelling describes as additional measures that are needed to be taken as it has been associated with settlement due to changes of stress and strength of the soil induced by tunnelling. Segmental tunnel lining is a structure used to support the ground and to have allowable movement due to soil stress redistribution. The research will be focusing on the type of modelling, structure parameter of the tunnel, pressure upon the tunnel lining and relationship with the induced ground settlement. Tunnel modelling was done in three dimensional (3D) modelling using ABAQUS software; of tunnel as parameter. This paper will discuss the effect of jack forces to the global behavior of the tunnel in order to support the surrounding load, thus be able to handle the tunnel-soil reaction without any visible or critical deformation, so that the tunnel can be used in the stable condition. A stand-alone ring method together with all-in-once method was used to simulate the Singapore MRT Circle Line 3 (CCL3). In the findings, when the tunnel lining thickness is reduced, the settlement of the ground surface is increased. Jack forces is also one of the reason of the tunnel to distort and the effect is more visible on the rings with reduced thickness compared to original thickness of the tunnel lining.

Impact of examining additional deeper sections on the pathological diagnosis of endoscopically resected early gastric cancer.

The pathological diagnosis of endoscopically resected early gastric cancer (EGC) is performed by evaluating a few representative sections from the specimen. We aimed to determine whether evaluating twice as many sections as usual by essentially cutting the original sections in half could improve the pathological diagnosis of EGC. We retrospectively investigated 85 EGC in 82 patients who had undergone endoscopic resection at our hospital from August 2008 to October 2012. EGC without indications of curative resection were excluded. We re-examined the original paraffin blocks after shaving away approximately half their original thickness, and evaluated whether the pathological diagnoses were affected. This technique essentially doubled the number of sections examined. Ten pathological diagnoses of 68 EGC (14.7%) were changed from curative resection to non-curative resection when we evaluated twice as many sections as in the standard method. The median tumor size was 25mm in the changed diagnosis group versus 14.5mm in the no change group (P=0.03). The univariate analysis also showed that tumor size was a significant predictor of changed diagnosis (P=0.015). Both the changed diagnosis group and no change group had no recurrence during follow up. Histological evaluation of twice as many sections as usual changed the initial pathological diagnosis of EGC, although the clinical implication of an additional deeper section was controversial because there was no recurrence. Our analysis also emphasized the importance of detailed histological evaluation to confirm a radical cure in endoscopic resection, especially in the case of larger EGC.