bluuebunny/crossref_metadata_2025 huggingface dataset:
Residual stress redistribution during elastic shake down in welded plates
Authors: Chukkan Jazeel R. , Wu Guiyi , Fitzpatrick Michael E. , Eren Elvin , Zhang Xiang , Kelleher Joe
Published: May 2018

Residual stresses are a consequence of welding in various structures such as ships and offshore structures. Residual stresses can be relaxed or redistributed according to the load levels during operation. The elastic shakedown phenomenon can be considered as one of the reasons for this change. This paper studies the relaxation/redistribution of weld residual stress during different levels of shakedown in a butt-welded plate chosen according to ship design and welding procedures. Welding was performed on DH36, a ship structural steel. Neutron diffraction was used to measure residual stresses in these plates in the as-welded state and after different levels of shakedown. A mixed hardening model in line with the Chaboche model is determined for both weld and base material. A numerical model is developed to estimate the shakedown limit on butt-welded plate. Further, the redistribution of residual stress in a numerical weld model according to the different levels of shakedown limit is studied. Based on the shakedown limit of the butt-welded plate, a shakedown region is determined, where the structure will undergo elastic shakedown in the presence of an existing residual stress field if the maximum stress on the load section after a few initial cycles is in the shakedown region.
Hydrogen Embrittlement Mechanism in Fatigue Behaviour of Austenitic and Martensitic Stainless Steels
Authors: Brück Sven , Schippl Volker , Christ Hans-Jürgen , Fritzen Claus-Peter
Published: May 2018

In the present study, the influence of hydrogen on the fatigue behaviour of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations was the changes in the mechanisms of short crack propagation. The aim of the ongoing investigation is to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions.
Fatigue investigation of complex weldments by the means of the local strain energy density approach
Authors: Viespoli Luigi Mario , Alvaro Antonio , Nyhus Bård , Berto Filippo
Published: May 2018

The paper investigates the use of an energetic approach based on the strain energy density failure criteria to predict the fatigue life of welded joints in aluminum alloy. The cited criterion has already been proved valid to assess the failure of components in presence of sharp and blunt notches, and several results are present in the literature for different materials. The geometry tested in the present work is a double V-grooved full penetration butt weld, subsequently heat treated, and loaded orthogonally to the welding direction with load ratio R=0. This configuration makes the weld toe a notch of great opening angle. The aim of the paper is to verify the soundness of the energetic criteria for this class of welded joints, comparing the tests results with the numerical predictions. In the computational part, the energy in a given volume can be computed directly from the nodal displacements, thus not needing the stress values. Differently from the stress intensity factor approach, this property allows to a fast computation of the strain energy density by the means of a coarse mesh. The results of different configurations of geometry and meshing are compared to find the simplest modeling scheme capable of providing an accurate estimate of the fatigue life of the joint.
Modeling of hydrogen effects on short crack propagation in a metastable austenitic stainless steel (X2CrNi19-11)
Authors: Schippl Volker , Brück Sven , Christ Hans-Jürgen , Fritzen Claus-Peter , Schwarz Martina , Weihe Stefan
Published: May 2018

The experimentally observed short fatigue crack growth rate of an uncharged specimen tested in air is compared with results obtained from specimens tested in 10 MPa hydrogen atmosphere and specimens previously charged with hydrogen. To further discuss the hydrogen related short propagation mechanisms, a simulation approach for predicting short fatigue crack growth is presented. The boundary element method is used for calculating stresses and displacements in an anisotropic elastic solid. The hydrogen concentration is assumed to be homogeneously distributed in the microstructure. Based on this modelling approach, it could be concluded that hydrogen leads to an increasing short fatigue crack growth rate due to increasing irreversible deformation processes at the crack tip and also promotes grain boundary cracking in specimens tested in 10 MPa hydrogen atmosphere.
Identification of fatigue damage evolution in 316L stainless steel using acoustic emission and digital image correlation
Authors: Tanvir Farhan , Sattar Tariq , Mba David , Edwards Graham , Eren Elvin , Lage Yoann
Published: May 2018

One of the main objectives of Acoustic Emission (AE) monitoring is to identify approaching critical stage of damage in the structure before it fails. State-of-the-art AE analysis is done on the features in both the time and frequency domains. Many features such as centroid frequency, duration, rise-time, count and energy are dependent on acquisition settings; threshold and timing parameters. Incorrect acquisition settings may result in inaccurate classification of the AE source. This work proposes a new feature in the time domain signal based on 2nd order Renyi’s entropy, which proves to be efficient in identifying different stages of damage. Renyi’s entropy is a measure of uncertainty or randomness of the signals and is directly derived from the distribution of signal amplitude. Therefore, it is independent of threshold and timing parameters. The validity of the proposed parameter is investigated by performing AE monitoring during fatigue endurance test of 316L stainless steel. Digital Image Correlation (DIC) and global strain monitoring was carried out to relate material damage with AE activity. The result shows Renyi’s entropy to be an effective measure to identify critical stages of damage in the material.
Effect of Temperature on Strawbale Wall Rendered with Laterite and Clay Nanoparticle
Authors: Adedeji Adeola A. , Ibiyeye Aminu , Adedeji Abiola M
Published: May 2018

In this study, the influence of the plastering materials on the thermal performance of three (3) straw bale building models were evaluated. The plastering materials considered are laterite mortal, laterite mortal with nanoparticle clay screeding and cement-sand mortal. The results were based on the experimentally measured thermal conductance, thermal resistance and thermal transmittance of the building model according to ASTM C1045-90 standard specification. The analysis of the measured data revealed that the laterite plaster significantly improve the thermal resistivity of the building model compared to cementsand mortal. However, clay nano particle screeding on the laterite plaster does not significantly affect the thermal performance of the straw bale building model.
The effects of shot peening on subsurface layer properties and fatigue performance of case-hardened 18CrNiMo7-6 steel
Authors: Ho Hsin Shen , Xie Junfeng , Sun Lingli , Niu Penghui , Zhang Erliang
Published: May 2018

The present study is conducted with a dual-aim; firstly, examine the effect of several single shot peening conditions on the subsurface layer properties and fatigue performance of the case-hardened 18CrNiMo7-6 steel. By carrying out the subsurface integrity analysis and fatigue testing, the underlying relationships among the peening process, subsurface layer property and fatigue performance are investigated, the way peening conditions affect the fatigue life and its associated scatter for the casehardened 18CrNiMo7-6 steel is quantitatively assessed.
Increasing fatigue performance in AHSS thick sheet by surface treatments
Authors: Parareda Sergi , Lara Antoni , Sieurin Henrik , D´Armas Héber , Casellas Daniel
Published: May 2018

Advanced High Strength Steels (AHSS) have been widely applied in the automotive industry as an affordable solution for car lightweighting, mainly in parts subjected to crash requirements. Heavy duty vehicle (HDV) can also benefit from the expertise learned in cars, but parts must be designed considering fatigue resistance, especially on trimmed areas, and stiffness. Mechanical surface treatments, as blasting or shot peening, help increasing fatigue life of AHSS in trimmed areas and will allow weight reduction in HDV through gauge downsizing. The expected decrease in stiffness through thickness reduction can be improved by design changes. However, scarce information about the effect of mechanical surface treatments on AHSS are available. Thus, the aim of this work is to evaluate the increment in fatigue life of two different steel grades (350 MPa, and 500MPa of yield strength) in thick sheet by means of mechanical surface treatment – sandblasting. High Cycle Fatigue [HCF] tests were conducted at alternating load [R=-1]. Residual stresses were measured by an X-ray tensometry prior fatigue tests. Also the surface roughness [Rz] and form is measured using an optical non-contact 3D microscope. On the other hand, the fracture surfaces of the test specimens were observed via scanning electron microscope (SEM) in order to determine the crack initiation points. The evaluation of fatigue life in terms of SN curves is also discussed, analysing how the sandblasting process modifies the surface roughness and introduce compressive residual stresses on the external layer of the material. Both phenomena enhance the fatigue strength of the evaluated steel grades.
An ad-hoc fretting wear tribotester design for thin steel wires
Authors: Llavori Iñigo , Zabala Alaitz , Urchegui Mikel Aingeru , Tato Wilson , Aginagalde Andrea , Garate Iñaki , Gómez Xabier
Published: May 2018

Steel wire ropes experience fretting wear damage when the rope runs over a sheave promoting an oscillatory motion between the wires. Consequently, wear scars appear between the contacting wires leading to an increase of the stress field and the following rupture of the wires due to fatigue. That is why the understanding and prediction of the fretting wear phenomena of thin wires is fundamental in order to improve the performance of steel wire ropes. The present research deals with the design of an ad-hoc fretting wear test machine for thin wires. The test apparatus is designed for testing thin wires with a maximum diameter of 1.0 mm, at slip amplitudes ranging from 5 to 300 μm, crossing angle between 0-90°, and contacting force ranging from 0,5 to 5 N. The working principle of displacement amplitude and contacting force as well as the crossing angle between the wires are described. Preliminary studies for understanding the fretting wear characteristics are presented, analysing 0.45 mm diameter cold-drawn eutectoid carbon steel (0.8% C) wires (tensile strength higher than 3000 MPa).
A simple expression to estimate the fatigue endurance of welded joints
Authors: Chapetti Mirco Daniel , Steimbreger Ceferino
Published: May 2018

A simple expression is proposed to estimate the fatigue endurance of welded joints that can be used to understand and analyze in a simple way the influence of the main geometrical, mechanical and material effects (weld geometry, local geometry, material properties, residual stresses and size of defects). The proposed expression was derived from the results of the analysis of the fatigue strength of welds studied by means of a fracture mechanics approach that takes into account the fatigue behavior of short cracks by using the resistance curve method. For that purpose numerical simulation of transversely stressed butt, T and cruciform joints were performed.
A new method for evaluating the influences of surface topography on fatigue propriety of the random machined surfaces
Authors: Ma Lin , Xu GuangTao , Wang Gang , Zhao MingHao
Published: May 2018

The Stress concentration factor (SCF) induced by the machined surface is more complex than that resulting from macro-geometry discontinuities and has great effect on fatigue life of structure. However, another important parameter, stress gradient (SG), was always ignored. The notch roots or valleys of the wave surface constitute fatigue hot points, where cracks occur, so it is essential to study the SCF and SG at valleys rather than just the root-mean-square SCF variable. In this work, a new method for evaluating the influences of surface topography on fatigue propriety of the random machined surfaces was given. An analytical method using Fourier transformation to simulate machined surface topography is presented. Analytical formulae for SCF and SG for random machined surfaces are derived subjected to a general loading and validate these formulae via finite element method (FEM). Joint probability-distribution function for SCF and SG at the valleys of the random machined-surface topography of the machined sample was obtained after different cycles fatigue test. This method gave us how the surface topography effect the fatigue properties of machined components. Fatigue test of machined sample for a single crystal nickel based alloy were established for validated this method. The obtained results should be useful in studying and evaluating fatigue properties of machined components.
Interface damage model for fatigue-driven fracture
Authors: Geng Feiyu , Suiker Akke S. J.
Published: May 2018

A fatigue interface damage model is presented that is based on combining a fatigue evolution law with a static interface damage model. The fatigue model elegantly enables the simulation of crack initiation and propagation in a computationally efficient and accurate way, accounting for mixed-mode loading conditions and fatigue loading of variable amplitude. The main features of the fatigue model are explained and demonstrated by means of an illustrative numerical example.
The study of the relationship between life limiting factor and stress level for FGH96
Authors: Yang Didi. , Shi Yi. , Miao Guolei. , Yang Xiaoguang. , Shi Duoqi.
Published: May 2018

FGH96 is a Chinese made powder metallurgy nickel based superalloy. This reserach aims to investigate the effect of stress on the microstructure of the worst fatigue life at 600°C. The specimens were first polished by abrasive paper and then electropolished to elimate the effect of surface residual stress. The fatigue tests were conducted at 600°C, and the loading ratio was 0.05 at the frequency of 5Hz. Tests were conducted at 900, 1000, 1100, 1200MPa respectively. The fatigue life under the same condition were compared and the fractography of specimens were examined under SEM to further identify the life-limiting factors of the material. The initiation mode transferred from facet initiated to inclusion initiated from lower stress level to higher stress level. Meanwhile, the initiation position transferred from internal to surface with the increase of stress level. This means at higher stress level, fatigue life is mainly limited by inclusion at surface while at lower stress level the limit is controlled by internal facet.
Experiment and CFD simulation of exhaust tube in highvoltage circuit breaker
Authors: Ye Xiangyang , Pisu Francesco , Grob Stephan , Dhotre Mahesh , Mantilla Javier
Published: May 2018

In a high-voltage circuit breaker, the exhaust tube connects the arc zone with the exhaust volume. During the arc interruption process, the exhaust tube transports the hot gas from the arc interruption zone to the exhaust volume through its distributed holes. The design of a high performance exhaust tube in the circuit breaker development aims for well controlled hot gas evacuation mass flow and pressure waves. In this paper, the exhaust tube behaviour is investigated using Computational Fluid Dynamics (CFD). To verify the CFD simulation, a basic experimental study with pressure measurements at different positions of the exhaust tube is performed. Further, the design parameters influencing the exhaust tube behaviour and circuit breaker performance are investigated and discussed.
A green building information modelling approach: building energy performance analysis and design optimization
Authors: Chen Shang-yuan
Published: May 2018

This study concerning green BIM focuses on the integrated application of Building Information Modelling (BIM) and building performance analysis (BPA) software as tools for the design and analysis of building projects, and employs a sequential decision-making cycle and continuously improving design to achieve an optimal proposal consistent with environmental effectiveness. Taking a new Taichung hotel construction project energy consumption design optimization as an example, this study relied on the steps of (1) Determination of the scope of discussion of the proposal within the building life cycle, (2) Setting of energy conservation targets, (3) Accessing to external climate data, (4) Entering internal settings, (5) Implementation of energy conservation calculation module, (6) Visualization analysis and hot spot tracking (7) Proposal Revision, and (8) Optimal proposal, to verify the green BIM concept. With regard to the setting of energy conservation targets, this study recommends that building energy use intensity (EUI) be used as an energy load measurement unit of integrated performance indicators, and employs performance optimization percentage as a rating criterion. In accordance with this method, green BIM combined with assessment of green building indicators is as a means of facilitating integrated design and analysis decision-making.
The influence of application processes on performance reliability
Authors: Zhang Yue , Huang Ning , Wu Weiqiang , Zhang Shuo
Published: May 2018

Application process has significant influence on network performance reliability, however, previous studies mainly focus on the impact of network characteristics (such as routing and traffic) on network performance reliability and ignore the influence of application process. In this paper, a multi-tiers model is proposed to capture the process of application. Furthermore, an application paths matrix is proposed to describe all the transmission paths of the application process in the network. Based on the application paths matrix, the boundary of the critical point of the traffic generation rate is derived theoretically, below the lower limit of the boundary the network stays in free-flow state and is reliable, while above the upper limit of the boundary the congestion occurs and the network performance reliability decreases. Furthermore, the effect of the boundary is verified in numerical simulations. The simulation results also show that congestions occurred in middle-tier host nodes could bring more influence on the network performance reliability.
The novel cloud application technology with virtual platform
Authors: Chen Ying-Chuan , Tsai Yi-Lang
Published: May 2018

Virtualization technology of cloud application service is the major research issue in recent years. Our virtual platform can obtain a lot of advantages base on virtualization technology with suitable virtual machine solution that all system resources can deployed quickly and managed competently, and it has some features including the high capacity for reliability, elasticity and customization. In our virtual platform, there are many different application services are provided for cloud service style. For system computing resources, we need to share all of system and software resources using the virtualization technology is presented in related sections, and we proposed virtual and remote application technology to implement innovative, convenient and powerful cloud application service base on virtual platform. For users of our platform, they can easy to use any software and tools on demand with pay per use mode anytime, and they do not have specialized knowledge and ability of install and maintenance.
Affectivity of biological cement's application to sandy soil for geotechnical engineering
Authors: Yi Hung Wen , Yuliani Emma , Handayani Maytri , Sseng Hsu Chia , Ching Chen Ssu
Published: May 2018

In this research, the authors analyze the addition of bacterial producer of biological cement on sandy soil to increase its stability. Pseudomonas sp was injected into the soil to produce urease enzyme, which converts urea that reacted with water become ammonium and carbonate, causing calcite precipitation. Soil stability can be improved by the production of pore-filling materials and particle-binding materials through the calcite precipitation process. The aim of these applications is to improve the mechanical properties of soil that it will be more suitable for construction or environmental purposes. After bacterial inoculation, the experiment with variation of bacterial content concluded the best way to increase soil stability is inject 15% bacteria relative to total weight of soil. Highest permeability reduction is 73,73% and highest shear strength increation for cohesion is 6,84 with friction angle 44,46°. California Bearing Ratio test with 10 of hits generated that the treatment soil can proved a significant penetration stress changed. From Environmental Scanning Electron Microscopy test results of the inoculation sand test images and surface scan, the formed exopolysaccharide attached to the wall of the sand soil particles which expected will fill, patch, and close the pores between the sandy soil particles.
Thermal hazard assessment of TMCH mixed with inorganic acids
Authors: Yeh Chi-Tang , Chen Wei-Chun , Shu Chi-Min
Published: May 2018

1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH) is a typical peroxide with two peroxy groups that may runaway and/or explode due to mixing with inorganic acids, such as HCl, HNO3, H2SO4, or H3PO4. In this study, reactivities of TMCH mixed with the above inorganic acids were assessed by differential scanning calorimetry (DSC). Furthermore, data obtained by DSC, such as exothermic onset temperature (T0), maximum temperature (Tmax), and heat of decomposition (ΔHd) could be employed to acquire thermal safety parameters. Moreover, thermal activity monitor III (TAM III) was employed to investigate the thermal hazards while storing or transporting TMCH and TMCH mixed with four types of commonly used inorganic acids, here as HCl, HNO3, H2SO4, or H3PO4 under isothermal conditions. Mixing TMCH with those inorganic acids resulted in higherΔHd except H3PO4, and mixing TMCH with HCl clearly decreased T0. Therefore, the phenomena of mixing those incompatible materials with TMCH can be concluded as the worst cases in terms of contamination hazards during storage and transportation of TMCH.
Opportunity recognition for small businesses in medical tourism in Taiwan
Authors: Hung Ying-Hsun , Chou Jerome Chih-Lung , Ma Jung , Lin Ching-pei
Published: May 2018

Medical tourism has become an investment focus for many Asian countries. For example, India, Singapore, Thailand, South Korea, and Malaysia have governmental projects to foster this emerging industry, and successfully attract millions of medical tourists each year. Medical tourism consists of diverse industries that can provide abundant opportunities of new businesses. Currently Taiwan is trying to catch up in this trend by making national development policies, setting up institutions, modifying laws and regulations, and encouraging investment of private sector. The purpose of this study is to analyze the status quo of international medical tourism in Taiwan, and identify several opportunities for small businesses to catch and to participate in forming a solid medical tourism industry for Taiwan.
Study on adult career planning on adult education program and assessment of adaptive design model
Authors: Kao I-Chan
Published: May 2018

This study explores adults‘ on-the-job current career planning and the selection trends of future development as the criteria for a training program design for adult education and the basis of the design model of adaptive assessment. This study regards the contents of the TTQS training process, the items, indicators, and standards of the Workforce Development Agency, and the occupational categories of the “Occupational Competency Standards”, as disclosed by the “Integrated Competency and Application Platform”, as the framework for the reference model; and probes into the impact of globalization, adult career planning, adult occupational training program design, and adaptive assessment, and adopts a questionnaire survey to understand the design model of the adaptive adult education program, in order to effectively implement adaptive assessment. The purposes are to assist adults to accomplish adaptive career planning, achieve their goals of vocational cultivation, and solve the problems of adult unemployment, in order to lead to successful adult employment and transfer to globalization workplaces to create positive career development.
Empirical Study on elderly learners’ needs and obstacles in network learning by “3C products”
Authors: Kao I-Chan
Published: May 2018

This study treated elderly learners at Open University of Kaohsiung who participated in online distance learning as samples. By a literature review and questionnaire survey, it probed into elderly learners’ perceived reactions and feedback for network learning using consumer electronics products and analyzed the general situation and relationship between elderly learners’ needs and obstacles in network learning with consumer electronics products. By empirical research, this study investigated a total of 472 elderly learners aged at least 55 years old in elderly programs at Open University of Kaohsiung, for-credit continuing education courses, and on-the-job courses of universities in different counties and cities around Taiwan. This study found that elderly learners with a lower educational level encounter more significant learning obstacles in network learning using consumer electronics products. In addition, this study found that when elderly learners’ needs to apply consumer electronics products are higher, their network learning obstacles will be lower. Based on the findings, this study suggested that it shall help elderly learners with lower educational level reinforce learning knowledge and competence to apply consumer electronics products to avoid obstacles for network learning.
Optimum distance for voice navigation in walking support system for visually impaired
Authors: Ohfuji Akinari , Taniura Yoshihiro , Hanawa Dai , Oguchi Kimio
Published: May 2018

Voice navigation with information and communication technologies allows the visually impaired (VI) to grasp the current situation promptly. While instruction prior to the action e.g. turning a corner, seems to be effective, the optimum lead distance remains unclear. This paper verifies experimentally the optimum lead distance to support VI while walking. In the experiment, each subject (normal vision) walked while wearing an eye mask to simulate VI, holding a white cane, and received voice guidance. After each trial, the subject scored the lead distance in terms of acceptability. 28 young healthy males/females participated. Results showed the highest score was for 3 m while the lowest was for 5 m. Distance range with score over 3 (average) was 2 to 4 m. No clear significant difference was observed in terms of subject height. As walking speed was around 0.55 m/s, 1 m was deemed insufficient. 5 m or more seemed to be too long as subjects failed to predict accurately how far they had moved. This experiment verified that VI voice navigation turn instructions are effective if given more than 1m and less than 4 m before the turning point.
Withdrawn article: Parametric study on soil-pile interaction failure using numerically research
Authors: Maula Baydaa Hussain , Al-Adhadh Ahmed Raad
Published: May 2018

This article has been withdrawn by the authors. Request approved by the editors and the publisher on June 6, 2018.
Steering test of mid-size bus with flexible-body dynamics model
Authors: Chen Jia-Shiun , Hwang Hsiu-Ying
Published: May 2018

The object of this paper is to analyze the vehicle structural vibration responses during the step steering simulation test. With computer simulations, confirming the influence from the difference between configurations of components on mid-size electrical bus and tradition one could be possible. The difference of the vibration responses between flexible multi-body model and rigid one would be discussed. Since the wheel base of mid-size bus is longer than passenger car, the deformation of vehicle body more obviously influences the output of vibration response. The operating condition in practical driving can be expressed by flexible model, and the performance prediction of vehicle can be closer to the real vehicle behavior. The difference between the flexible body simulation and rigid body simulation is 1.17%, and the flexible body model is more practical.
Necessity for diversity of commercial facilities for daily shopping in residential planninga
Authors: Chen Pingli , Yen Yungchi
Published: May 2018

Since the 1990s, the government administrations have thought that supermarkets could replace traditional retail markets as the commercial facilities for daily shopping in Taiwan. However, traditional retail markets remained prosperous. This paper aims to investigate the followings: 1) whether traditional retail markets still play an important role in residents’ daily shopping and 2) whether supermarkets and traditional retail markets are actually complementary rather than competitive as commercial facilities for daily shopping. The examination is based on the data regarding married women’s daily shopping behaviours in a planned residential area in Taipei from a questionnaire carried out in 2007. Several things are concluded below. First, consumers do not definitely choose the new types of facilities for daily shopping. Second, supermarkets in residential areas may be complementary to traditional retail markets in residents’ daily shopping. Third, traditional retail market plays a role beyond acting as the exchange space for goods. Fourth, even though cars are popular in Taiwan, married women still prefer to conduct their daily shopping inside or nearby their neighbourhood unit by walking. This paper suggests it is necessary to maintain diversity rather than to anticipate or limit the type of commercial facilities available for daily shopping in residential planning.
Modeling and simulation of brain herniation caused by subdural hematoma using finite-element method
Authors: Huang Ke-Chun , Xiao Furen , Chiang I-Jen , Chen Yi-Long , Tsai Yi-Hsin , Wong Jau-Min , Liao Chun-Chih
Published: May 2018

Brain shift and herniation are important signs of increased intracranial pressure (ICP) caused by hematomas or other types of intracranial mass. We propose a novel finite-element model that can be deformed in response to increased ICP. The half sphere model of the brain is partially divided into two compartments by the intact mid-sagittal plane, allowing subfalcine herniation. A 40 mm circle in the center of its equatorial plane allows transtentorial herniation. We perform a single load step, structural static analysis, simulating a left-sided subdural hematoma (SDH) compressing the cerebral hemispheres from the outer surface of the left hemisphere. Subfalcine and transtentorial brain herniations are reproduced and visualized. The Poisson’s ratio represents the tightness of the brain and the pressure load represents the ICP. There is a linear relationship between maximal deformation and the pressure load. The maximal deformation at the basal circumference and that at the basal midline closely resembles the maximal thickness of the SDH and the midline shift. We have developed a simple finite-element model that can simulate brain shift and herniation caused by pressure loads exerted on its surface by a mass. The experimental results correlate well with clinical observation on patients with acute and chronic SDH.
First-Bite syndrome and Eagle syndrome
Authors: Gauthier Benat , Ségolène Georg , Bruno Courtois
Published: May 2018

Introduction: Eagle Syndrome (ES) is caused by the ossification/calcification of the stylohyoid ligament and is associated with many different symptoms such as otalgia, restricted mouth opening, or an intrapharyngeal foreign body sensation. First-bite syndrome (FBS) is characterized by pain in the parotid and retromandibular region, when taking the first bite in a meal and occurs more or less invariably. Observation: A 50-year-old female patient presented complaining of right retromandibular pain, that irradiated to the right side of the mandible and right shoulder, only when eating for the first time a day and at the first bite. Medical history and clinical examination did not reveal any signs of cervical surgery or cervical trauma. Palpation was painful at a specific point in right retromandibular point region, the rest of the intraoral and extraoral examinations were normal. The right and left condylar x-rays (open mouth and closed mouth) revealed an elongation of both the right and left stylohyoid ligaments. Discussion: Usually, FBS occurs after cervical surgery, for example after resection of the stylohyoid ligament for ES. Our case report shows, on the contrary, FBS that was associated with ES. The pathophysiological explanation of FBS depends on an irritative or traumatic factor in the sympathetic nerve fibers of the parotid gland. Conclusion: This association allows us to present both syndromes and to carry out an up to date pathophysiological examination and therapeutic proposals concerning FBS.
Recognition accuracy of tumor extent using a prototype 3D endoscope for superficial gastric tumor: an ex vivo crossover study
Authors: Nomura Kosuke , Kaise Mitsuru , Kikuchi Daisuke , Iizuka Toshiro , Fukuma Yumiko , Kuribayashi Yasutaka , Tanaka Masami , Toba Takahito , Furuhata Tsukasa , Yamashita Satoshi , Matsui Akira , Mitani Toshifumi , Hoteya Shu
Published: May 2018

Background and study aims Many studies have shown the utility of rigid three-dimensional (3 D) endoscopes in surgery, but few have reported the utility of flexible 3 D endoscopes. This ex vivo study was intended to investigate whether a newly developed 3 D endoscope (GIF-Y0083; Olympus) improves diagnostic accuracy for superficial gastric tumor.

Methods Twelve observers comprising experts, trainees, and novices (4 each) evaluated 2 D and 3 D images of 20 specimens resected by gastric ESD. Evaluation items were diagnostic accuracy of tumor extent and degree of confidence in assessing (a) tumor extent, (b) morphology, and (c) comprehensive recognition. The 2 D and 3 D endoscopy data were compared in a crossover analysis.

Results Overall, diagnostic accuracy was significantly higher with 3 D images (88.1 %) than with 2 D images (84.2 %) (P < 0.01). Comparison by skill level showed that 3 D images significantly improved diagnostic accuracy among novices but not among experts or trainees. Comparison by morphology showed that diagnostic accuracy did not differ significantly for type IIa/IIb lesions but improved significantly for type IIc lesions among trainees and novices. Overall, 3 D images significantly increased the degree of confidence in the assessment of all three items (a – c). Comparison by skill level showed similar results, and comparison by morphology showed that regardless of skill level, the degree of confidence in assessing all items (a – c) increased significantly only when examining type IIc lesions.

Conclusion Compared with 2 D images, 3 D images significantly improved both diagnostic accuracy of tumor extent and degree of confidence for diagnosing superficial gastric tumor. The utility of the 3 D endoscope was apparent among trainees and novices and for the diagnosis of type IIc lesions.
Diagnostic yield and predictive factors of findings in small-bowel capsule endoscopy in the setting of iron-deficiency anemia
Authors: Olano Carolina , Pazos Ximena , Avendaño Karla , Calleri Alfonso , Ketzoian Carlos
Published: May 2018

Introduction Despite the widespread use of small-bowel capsule endoscopy (CE), there is still limited data on its utility and effectiveness for the diagnosis and management of patients with iron-deficiency anemia (IDA).

Aim To assess the diagnostic yield of CE and the factors predicting positive findings in patients with IDA.

Methods Patients with unexplained IDA and negative upper and lower endoscopy were included. A positive diagnostic yield was considered when CE diagnosed one or more lesions that could explain the IDA. Sex, age, NSAID consumption, blood transfusion requirement, and ferritin and hemoglobin levels were recorded.

Results In total, 120 CE were included (mean age 58.5 years; F/M 82:38). Mean hemoglobin levels were 9 g/dL and mean ferritin levels were 15.7 ng/mL. Positive findings were present in 50 % of patients. The most frequent was angiodysplasia (45 %). Despite several baseline variables being significantly associated with positive findings, using a logistic regression model, it was verified that male sex (OR 3.93; 95 %CI 1.57 – 9.86), age (OR 1.03; 95 %CI 1.00 – 1.06), and hemoglobin levels (OR 0.73; 95 %CI 0.57 – 0.94) were the variables having an independent effect on the probability of obtaining positive findings. Age older than 50 years (OR 14.05; 95 %CI 1.69 – 116.23) and male sex (OR 3.63; 95 %CI 1.29 – 10.17) were the variables which increased the risk of diagnosing angiodysplasia.

Conclusions CE is a useful technique in patients with IDA. To improve its yield, it is necessary to select patients carefully. Male sex, older age, and low hemoglobin levels were associated with a risk of positive finding in this group of patients. The risk of diagnosing angiodysplasia increased with male sex and older age.
Outcomes of repeat balloon assisted enteroscopy in small-bowel bleeding
Authors: Al-Bawardy Badr , Piovezani Ramos Guilherme , Lennon Ryan , Gorospe Emmanuel , Wong Kee Song Louis , Bruining David , Alexander Jeffrey , Coelho-Prabhu Nayantara , Fidler Jeff , Rajan Elizabeth
Published: May 2018

Background/aims The rate of recurrent small-bowel bleeding (SBB) remains high despite the advent of balloon assisted enteroscopy (BAE). The study aims were to determine: (1) the diagnostic and therapeutic yields, and adverse event rate of repeat BAE in SBB, and (2) the predictors of a positive repeat BAE.

Methods A retrospective review of a BAE database was conducted. Patients who had > 1 BAE for SBB were included. Primary outcomes were diagnostic yield, therapeutic yield, and adverse events of repeat BAE. Secondary outcomes were predictors of a positive repeat BAE.

Results A total of 175 patients (55 % men; mean age 64.1 ± 16.3 years) were included. The diagnostic and therapeutic yields of repeat BAE were 55 % and 42 %, respectively. Repeat BAE adverse events occurred in 5 % with self-limited abdominal pain being most common. Patients with a positive repeat BAE were significantly older than the negative group (68.6 ± 13.9 vs. 60.9 ± 17.1; P = 0.001) and were more likely to have cardiac comorbidities (OR 2.4, 95 %CI: 1.3 – 4.6; P = 0.01), chronic kidney disease (OR 2.3, 95 %CI: 1.1 – 4.9; P = 0.04), chronic obstructive pulmonary disease (OR 3.3, 95 %CI: 1.3 – 8.1; P = 0.01), positive initial BAE (OR 3.6, 95 %CI: 1.9 – 6.8; P < 0.001), and antegrade procedure (OR 3.3, 95 %CI: 1.7 – 6.1; P < 0.001). On multivariate analysis, a positive initial BAE and antegrade route were the only significant predictive factors.

Conclusions Performing a repeat BAE for SBB appears safe and provided modest yields. A positive initial BAE and antegrade route were predictive of a positive repeat BAE.
Access to the Ischium: A Simple Extension of the Posterior Approach in Revision Hip Arthroplasty
Authors: Rueckl Kilian , Boettner Friedrich
Published: May 2018

Reconstruction of acetabular defects in revision total hip arthroplasty (THA) requires excellent exposure. Most extensile approaches to the acetabulum were described in the trauma literature and are not beneficial for revision THA. This article describes a modification of the standard posterior surgical approach to improve visualization of the ischium as required for acetabular defect reconstruction, insertion of standard and custom triflange cages as well as posterior column plating. The current surgical technique utilizes an intermuscular plane between the gemellus inferior muscle and the obturator externus muscle. This intermuscular plane leads the surgeon directly to the ischium and facilitates easy extension toward the insertion of the hamstring muscles without compromising the insertion of the external rotator muscles along the ischium. This article describes a novel surgical approach to the posterior column and ischium under special consideration of the sciatic nerve, superior gluteal vessels, and medial femoral circumflex artery. This simple extension of the standard posterior approach optimizes exposure of the posterior column during revision THA using a posterior approach.
Neonatal Alexander Disease: Novel GFAP Mutation and Comparison to Previously Published Cases
Authors: Knuutinen Oula , Kousi Maria , Suo-Palosaari Maria , Moilanen Jukka , Tuominen Hannu , Vainionpää Leena , Joensuu Tarja , Anttonen Anna-Kaisa , Uusimaa Johanna , Lehesjoki Anna-Elina , Vieira Päivi
Published: May 2018

Alexander disease (AxD) is a genetic leukodystrophy caused by GFAP mutations leading to astrocyte dysfunction. Neonatal AxD is a rare phenotype with onset in the first month of life. The proband, belonging to a large pedigree with dominantly inherited benign familial neonatal epilepsy (BFNE), had a phenotype distinct from the rest of the family, with hypotonia and macrocephaly in addition to drug-resistant neonatal seizures. The patient deteriorated and passed away at 6 weeks of age. The pathological and neuroimaging data were consistent with the diagnosis of AxD. Genetic analysis of the proband identified a novel de novo GFAP missense mutation and a KCNQ2 splice site mutation segregating with the BFNE phenotype in the family. The GFAP mutation was located in the coil 2B region of GFAP protein, similar to most neonatal-onset AxD cases with an early death. The clinical and neuroradiological features of the previously published neonatal AxD patients are presented. This study further supports the classification of neonatal-onset AxD as a distinct phenotype based on the age of onset.
A Rare Case of Spontaneous Mitral Leaflet Perforation Leading to Severe Mitral Regurgitation
Authors: Ari Ashok , Lalitha Nemani
Published: May 2018

Spontaneous mitral leaflet perforations are rare. We are reporting a 60 year old hypertensive female patient admitted with pulmonary edema with clinically short systolic murmur at apex without ischemic changes on ECG. There is no h/o chest pain, fever, blunt trauma of chest. TTE no RWMA, good bi- ventricular function, a posteriorly directed eccentric moderate – severe mitral regurgitation, normal LA, LV, no vegetation or prolapsed. TEE after stabilization showed whole in body of AML at its midpoint leading to severe regurgitant jet in to LA with Vena contracta of 0.8 mm. All the papillary muscles were intact and there is no prolapse of leaflets and no vegetation. Cardiac catheterization revealed increased LVEDP and PCWP with mild PAH with normal coronary arteries.
Outcomes of Coronary Angioplasty in Diabetic Patients – A Retrospective Study
Authors: Kishore Galla , Susmitha Chandragiri , Rao P
Published: May 2018

Aims: We want to study the effect of diabetes Mellitus (DM) on the outcomes in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) comparing those with non diabetics, with reference to gender.

Methods: We retrospectively evaluated the consecutive patients undergoing PCI either with acute coronary syndrome (ACS) or chronic stable angina (CSA) in our institute between March 2014 to March 2015. We followed them up to one year for the major cardiovascular events (MACES) and other complications. We compared the rate of events between diabetic and non diabetic patients along with gender subgroups and tested for the significance.

Results: In 645 patients undergone PCI in our institute, 326(50.5%) were diabetics, of them 104(31.9%) were females. Patients with diabetes with CAD were older with more incidence of hypertension and kidney derangement than non diabetics. History of CAD and previous procedure are definitely more in diabetics as is multi vessel disease (p=0.02) and LV dysfunction (p=0.003). Total number of patients presenting with complications within one year of PCI is 18(0.02%). Of them 14 are males and 4 are females, 14 were diabetics and 4 were non diabetics. There was no statistical significance in the outcomes between female & males (p=0.7), diabetics females & diabetic males (p=0.48) and non diabetics females & nondiabetic males(p=0.7). Male patients with diabetes had significantly more complications than non diabetic males (p=0.05) but there is no significant difference between diabetic and non diabetic females (p=0.59).

Conclusion: Patients with DM undergoing PCI had more complications than non diabetics with significant difference between male diabetics and non diabetic males. This difference is not significant between diabetic and non diabetic females.
WCC 2016-112: A case of varied presentation of thrombus
Authors: Kiran Ravi
Published: May 2018

Antiphospholipid syndrome is a well defined entity that is characterized by spontaneous abortion, thrombocytopenia, and recurrent arterial and venous thromboses. A right atrial thrombus mimicking myxoma with pulmonary thromboembolism in a patient with secondary antiphospholipid syndrome is rare.

Herein, we describe the case of a 35 year old woman who was admitted to the hospital with shortness of breath, swelling of both lower limbs. Transthoracic and transesophageal echocardiography showed a right atrial mass suggestive of myxoma, and the patient subsequently underwent surgery. A histologic examination of the mass showed myxoma. In our patient, the preoperative investigations could not differentiate the thrombus from a myxoma, and she was operated in outside hospital. Later she presented with deep vein thrombosis and pulmonary thromboembolism to our hospital and was diagnosed as having secondary antiphospolipid syndrome and the review sides of the right atrial mass showed thrombus. Intracardiac thrombus has been rarely reported as a compication of antiphospholipid syndrome.

Case report: In December 2015, a 35 year old woman was admitted to the hospital with swelling of both lower limbs since 15 days, shortness of breath since 15 days. She had a past history of acute left upper limb ischemia in 15/4/2013 for which catheter directed thrombolysis of brachial artery was done with steptokinase, coronary angiogram showed normal coronaries. History of cervical TB lymphadenitis for which she used ATT for 9 months in 2013. History of excision of right atrial myxoma was done on 3/11/15 at outside hospital. Histologic examination showed myxoma. Patient has pallor and bilateral pedal odema on general examination. At admission vitals were stable and systemic examination was normal except for raised jugular venous pressure. ECG showed T inversions in leads V 3-6, II, III, aVF. 2D ECHO showed dilated RA/RV severe TR, moderate PAH, RVSP 50 mm of Hg, TAPSE 1.3, good LV function, mild RV dysfunction, mobile thrombus at the junction of middle hepatic vein & IVC. CTPA showed saddle thrombus in PA extending into RPA, multiple collaterals in anterior & posterior chest wall with non visualisation of part of left subclavian vein.