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Sample records for rib shape model

  1. CFD Analysis on the Thermal Hydraulic Performance of an SAH Duct with Multi V-Shape Roughened Ribs

    Directory of Open Access Journals (Sweden)

    Anil Kumar

    2016-05-01

    Full Text Available This study presents the heat transfer and fluid flow characteristics in a rib-roughened SAH (solar air heater channel. The artificial roughness of the rectangular channel was in the form of a thin circular wire in discrete multi V-pattern rib geometries. The effect of this geometry on heat transfer, fluid flow, and performance augmentation was investigated using the CFD (computational fluid dynamics. The roughness parameters were a relative discrete distance of 0.69, a relative rib height of 0.043, a relative rib pitch of 10, a relative rib width of 6.0, and a flow-attack-angle of 60°. The discrete width ratios and Reynolds numbers ranged from 0.5 to 2.0 and from 2000 to 20,000, respectively. The CFD results using the renormalization k-epsilon model were in good agreement with the empirical relationship. This model was used to investigate the heat transfer and fluid flow characteristics in the multi V-pattern rib roughened SAH channel. The thermo-hydraulic performance was found to be the best for the discrete width ratio of 1.0. A discrete multi V-pattern rib combined with dimple staggered ribs also had better overall thermal performance compared to other rib shapes.

  2. Analysis and test of a 16-foot radial rib reflector developmental model

    Science.gov (United States)

    Birchenough, Shawn A.

    1989-01-01

    Analytical and experimental modal tests were performed to determine the vibrational characteristics of a 16-foot diameter radial rib reflector model. Single rib analyses and experimental tests provided preliminary information relating to the reflector. A finite element model predicted mode shapes and frequencies of the reflector. The analyses correlated well with the experimental tests, verifying the modeling method used. The results indicate that five related, characteristic mode shapes form a group. The frequencies of the modes are determined by the relative phase of the radial ribs.

  3. Model based rib-cage unfolding for trauma CT

    Science.gov (United States)

    von Berg, Jens; Klinder, Tobias; Lorenz, Cristian

    2018-03-01

    A CT rib-cage unfolding method is proposed that does not require to determine rib centerlines but determines the visceral cavity surface by model base segmentation. Image intensities are sampled across this surface that is flattened using a model based 3D thin-plate-spline registration. An average rib centerline model projected onto this surface serves as a reference system for registration. The flattening registration is designed so that ribs similar to the centerline model are mapped onto parallel lines preserving their relative length. Ribs deviating from this model appear deviating from straight parallel ribs in the unfolded view, accordingly. As the mapping is continuous also the details in intercostal space and those adjacent to the ribs are rendered well. The most beneficial application area is Trauma CT where a fast detection of rib fractures is a crucial task. Specifically in trauma, automatic rib centerline detection may not be guaranteed due to fractures and dislocations. The application by visual assessment on the large public LIDC data base of lung CT proved general feasibility of this early work.

  4. Shape accuracy optimization for cable-rib tension deployable antenna structure with tensioned cables

    Science.gov (United States)

    Liu, Ruiwei; Guo, Hongwei; Liu, Rongqiang; Wang, Hongxiang; Tang, Dewei; Song, Xiaoke

    2017-11-01

    Shape accuracy is of substantial importance in deployable structures as the demand for large-scale deployable structures in various fields, especially in aerospace engineering, increases. The main purpose of this paper is to present a shape accuracy optimization method to find the optimal pretensions for the desired shape of cable-rib tension deployable antenna structure with tensioned cables. First, an analysis model of the deployable structure is established by using finite element method. In this model, geometrical nonlinearity is considered for the cable element and beam element. Flexible deformations of the deployable structure under the action of cable network and tensioned cables are subsequently analyzed separately. Moreover, the influence of pretension of tensioned cables on natural frequencies is studied. Based on the results, a genetic algorithm is used to find a set of reasonable pretension and thus minimize structural deformation under the first natural frequency constraint. Finally, numerical simulations are presented to analyze the deployable structure under two kinds of constraints. Results show that the shape accuracy and natural frequencies of deployable structure can be effectively improved by pretension optimization.

  5. Application of the rainfall infiltration breakthrough (RIB) model for ...

    African Journals Online (AJOL)

    2012-05-23

    May 23, 2012 ... In this paper, the physical meaning of parameters in the CRD and previous ... ity; the utility of the RIB model for application in different climatic areas under ...... TMG Aquifer feasibility study and pilot project ecological and.

  6. Numerical investigations of rib fracture failure models in different dynamic loading conditions.

    Science.gov (United States)

    Wang, Fang; Yang, Jikuang; Miller, Karol; Li, Guibing; Joldes, Grand R; Doyle, Barry; Wittek, Adam

    2016-01-01

    Rib fracture is one of the most common thoracic injuries in vehicle traffic accidents that can result in fatalities associated with seriously injured internal organs. A failure model is critical when modelling rib fracture to predict such injuries. Different rib failure models have been proposed in prediction of thorax injuries. However, the biofidelity of the fracture failure models when varying the loading conditions and the effects of a rib fracture failure model on prediction of thoracic injuries have been studied only to a limited extent. Therefore, this study aimed to investigate the effects of three rib failure models on prediction of thoracic injuries using a previously validated finite element model of the human thorax. The performance and biofidelity of each rib failure model were first evaluated by modelling rib responses to different loading conditions in two experimental configurations: (1) the three-point bending on the specimen taken from rib and (2) the anterior-posterior dynamic loading to an entire bony part of the rib. Furthermore, the simulation of the rib failure behaviour in the frontal impact to an entire thorax was conducted at varying velocities and the effects of the failure models were analysed with respect to the severity of rib cage damages. Simulation results demonstrated that the responses of the thorax model are similar to the general trends of the rib fracture responses reported in the experimental literature. However, they also indicated that the accuracy of the rib fracture prediction using a given failure model varies for different loading conditions.

  7. Application of the rainfall infiltration breakthrough (RIB) model for ...

    African Journals Online (AJOL)

    Application of the rainfall infiltration breakthrough (RIB) model for groundwater recharge estimation in west coastal South Africa. ... the data from Oudebosch with different rainfall and groundwater abstraction inputs are simulated to explore individual effects on water levels as well as recharge rate estimated on a daily basis.

  8. Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures.

    Science.gov (United States)

    Casha, Aaron R; Camilleri, Liberato; Manché, Alexander; Gatt, Ruben; Attard, Daphne; Gauci, Marilyn; Camilleri-Podesta, Marie-Therese; Mcdonald, Stuart; Grima, Joseph N

    2015-11-01

    The human rib cage resembles a masonry dome in shape. Masonry domes have a particular construction that mimics stress distribution. Rib cortical thickness and bone density were analyzed to determine whether the morphology of the rib cage is sufficiently similar to a shell dome for internal rib structure to be predicted mathematically. A finite element analysis (FEA) simulation was used to measure stresses on the internal and external surfaces of a chest-shaped dome. Inner and outer rib cortical thickness and bone density were measured in the mid-axillary lines of seven cadaveric rib cages using computerized tomography scanning. Paired t tests and Pearson correlation were used to relate cortical thickness and bone density to stress. FEA modeling showed that the stress was 82% higher on the internal than the external surface, with a gradual decrease in internal and external wall stresses from the base to the apex. The inner cortex was more radio-dense, P rib level. The internal anatomical features of ribs, including the inner and outer cortical thicknesses and bone densities, are similar to the stress distribution in dome-shaped structures modeled using FEA computer simulations of a thick-walled dome pressure vessel. Fixation of rib fractures should include the stronger internal cortex. © 2015 Wiley Periodicals, Inc.

  9. Stabilization of multiple rib fractures in a canine model.

    Science.gov (United States)

    Huang, Ke-Nan; Xu, Zhi-Fei; Sun, Ju-Xian; Ding, Xin-Yu; Wu, Bin; Li, Wei; Qin, Xiong; Tang, Hua

    2014-12-01

    Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF. Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures. No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization. Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Biomechanical investigation of different surgical strategies for the treatment of rib fractures using a three-dimensional human respiratory model.

    Science.gov (United States)

    Shih, Kao-Shang; Truong, Thanh An; Hsu, Ching-Chi; Hou, Sheng-Mou

    2017-11-02

    Rib fracture is a common injury and can result in pain during respiration. Conservative treatment of rib fracture is applied via mechanical ventilation. However, ventilator-associated complications frequently occur. Surgical fixation is another approach to treat rib fractures. Unfortunately, this surgical treatment is still not completely defined. Past studies have evaluated the biomechanics of the rib cage during respiration using a finite element method, but only intact conditions were modelled. Thus, the purpose of this study was to develop a realistic numerical model of the human rib cage and to analyse the biomechanical performance of intact, injured and treated rib cages. Three-dimensional finite element models of the human rib cage were developed. Respiratory movement of the human rib cage was simulated to evaluate the strengths and limitations of different scenarios. The results show that a realistic human respiratory movement can be simulated and the predicted results were closely related to previous study (correlation coefficient>0.92). Fixation of two fractured ribs significantly decreased the fixation index (191%) compared to the injured model. This fixation may provide adequate fixation stability as well as reveal lower bone stress and implant stress compared with the fixation of three or more fractured ribs.

  11. Thermo-hydraulic performance of solar air heater having multiple v-shaped rib roughness on absorber plates

    Directory of Open Access Journals (Sweden)

    Dhananjay Kumar

    2018-03-01

    Full Text Available This paper presents the performance analysis of the effect of geometrical parameters having multiple v-shaped rib roughness on the airflow side of the absorber plates. Mathematical approach and solution procedure for the analysis of such a solar air heater has been developed theoretically and MATLAB code generated for the solution of the mathematical equations. The effect of parameters such as flow Reynolds number and Relative roughness height on the thermohydraulic performance have been examined and compared with the conventional flat plate solar air heater. A substantial improvement in thermal efficiency of roughened solar air heater as compared to smooth one due to appreciable enhancement in heat transfer coefficient. The enhancement in heat transfer coefficient is also accompanied by a considerable enhancement in pumping power requirement due to the increase in friction factor.

  12. Investigation of heat transfer and flow using ribs within gas turbine blade cooling passage: Experimental and hybrid LES/RANS modeling

    Science.gov (United States)

    Kumar, Sourabh

    Gas turbines are extensively used for aircraft propulsion, land based power generation and various industrial applications. Developments in innovative gas turbine cooling technology enhance the efficiency and power output, with an increase in turbine rotor inlet temperatures. These advancements of turbine cooling have allowed engine design to exceed normal material temperature limits. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream are based on the increase of heat transfer areas and on promotion of turbulence of the cooling flow. In this study, it is obtained by casting repeated continuous V and broken V shaped ribs on one side of the two pass square channel into the core of blade. Despite extensive research on ribs, only few papers have validated the numerical data with experimental results in two pass channel. In the present study, detailed experimental investigation is carried out for two pass square channels with 180° turn. Detailed heat transfer distribution occurring in the ribbed passage is reported for steady state experiment. Four different combinations of 60° and Broken 60° V ribs in channel are considered. Thermocouples are used to obtain the temperature on the channel surface and local heat transfer coefficients are obtained for various Reynolds numbers, within the turbulent flow regime. Area averaged data are calculated in order to compare the overall performance of the tested ribbed surface and to evaluate the degree of heat transfer enhancement induced by the ribs with. Flow within the channels is characterized by heat transfer enhancing ribs, bends, rotation and buoyancy effects. Computational Fluid Dynamics (CFD) simulations were carried out for the same geometries using different turbulence models such as k-o Shear stress transport (SST) and Reynolds stress model (RSM). These CFD simulations were based on advanced computing in order to improve the accuracy of three dimensional metal

  13. Application of the rainfall infiltration breakthrough (RIB) model for groundwater recharge estimation in west coastal South Africa

    CSIR Research Space (South Africa)

    Sun, X

    2013-04-01

    Full Text Available level fluctuations (WLF) on a monthly basis was proposed in the rainfall infiltration breakthrough (RIB) model for the purpose of groundwater recharge estimation. In this paper, the physical meaning of parameters in the CRD and previous RIB models...

  14. A comparison between rib fracture patterns in peri- and post-mortem compressive injury in a piglet model.

    Science.gov (United States)

    Bradley, Amanda L; Swain, Michael V; Neil Waddell, J; Das, Raj; Athens, Josie; Kieser, Jules A

    2014-05-01

    Forensic biomechanics is increasingly being used to explain how observed injuries occur. We studied infant rib fractures from a biomechanical and morphological perspective using a porcine model. We used 24, 6th ribs of one day old domestic pigs Sus scrofa, divided into three groups, desiccated (representing post-mortem trauma), fresh ribs with intact periosteum (representing peri-mortem trauma) and those stored at -20°C. Two experiments were designed to study their biomechanical behaviour fracture morphology: ribs were axially compressed and subjected to four-point bending in an Instron 3339 fitted with custom jigs. Morphoscopic analysis of resultant fractures consisted of standard optical methods, micro-CT (μCT) and Scanning Electron Microscopy (SEM). During axial compression fresh ribs did not fracture because of energy absorption capabilities of their soft and fluidic components. In flexure tests, dry ribs showed typical elastic-brittle behaviour with long linear load-extension curves, followed by short non-linear elastic (hyperelastic) behaviour and brittle fracture. Fresh ribs showed initial linear-elastic behaviour, followed by strain softening and visco-plastic responses. During the course of loading, dry bone showed minimal observable damage prior to the onset of unstable fracture. Frozen then thawed bone showed similar patterns to fresh bone. Morphologically, fresh ribs showed extensive periosteal damage to the tensile surface with areas of collagen fibre pull-out along the tensile surface. While all dry ribs fractured precipitously, with associated fibre pull-out, the latter feature was absent in thawed ribs. Our study highlights the fact that under controlled loading, fresh piglet ribs (representing perimortem trauma) did not fracture through bone, but was associated with periosteal tearing. These results suggest firstly, that complete lateral rib fracture in infants may in fact not result from pure compression as has been previously assumed; and

  15. Biomechanical investigation of impact induced rib fractures of a porcine infant surrogate model.

    Science.gov (United States)

    Blackburne, William B; Waddell, J Neil; Swain, Michael V; Alves de Sousa, Ricardo J; Kieser, Jules A

    2016-09-01

    This study investigated the structural, biomechanical and fractographic features of rib fractures in a piglet model, to test the hypothesis that fist impact, apart from thoracic squeezing, may result in lateral costal fractures as observed in abused infants. A mechanical fist with an accelerometer was constructed and fixed to a custom jig. Twenty stillborn piglets in the supine position were impacted on the thoracic cage. The resultant force versus time curves from the accelerometer data showed a number of steps indicative of rib fracture. The correlation between impact force and number of fractures was statistically significant (Pearson׳s r=0.528). Of the fractures visualized, 15 completely pierced the parietal pleura of the thoracic wall, and 5 had butterfly fracture patterning. Scanning electron microscopy showed complete bone fractures, at the zone of impact, were normal to the axis of the ribs. Incomplete vertical fractures, with bifurcation, occurred on the periphery of the contact zone. This work suggests the mechanism of rib failure during a fist impact is typical of the transverse fracture pattern in the anterolateral region associated with cases of non-accidental rib injury. The impact events investigated have a velocity of ~2-3m/s, approximately 2×10(4) times faster than previous quasi-static axial and bending tests. While squeezing the infantile may induce buckle fractures in the anterior as well as posterior region of the highly flexible bones, a fist punch impact event may result in anterolateral transverse fractures. Hence, these findings suggest that the presence of anterolateral rib fractures may result from impact rather than manual compression. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Failed rib region prediction in a human body model during crash events with precrash braking.

    Science.gov (United States)

    Guleyupoglu, B; Koya, B; Barnard, R; Gayzik, F S

    2018-02-28

    The objective of this study is 2-fold. We used a validated human body finite element model to study the predicted chest injury (focusing on rib fracture as a function of element strain) based on varying levels of simulated precrash braking. Furthermore, we compare deterministic and probabilistic methods of rib injury prediction in the computational model. The Global Human Body Models Consortium (GHBMC) M50-O model was gravity settled in the driver position of a generic interior equipped with an advanced 3-point belt and airbag. Twelve cases were investigated with permutations for failure, precrash braking system, and crash severity. The severities used were median (17 kph), severe (34 kph), and New Car Assessment Program (NCAP; 56.4 kph). Cases with failure enabled removed rib cortical bone elements once 1.8% effective plastic strain was exceeded. Alternatively, a probabilistic framework found in the literature was used to predict rib failure. Both the probabilistic and deterministic methods take into consideration location (anterior, lateral, and posterior). The deterministic method is based on a rubric that defines failed rib regions dependent on a threshold for contiguous failed elements. The probabilistic method depends on age-based strain and failure functions. Kinematics between both methods were similar (peak max deviation: ΔX head = 17 mm; ΔZ head = 4 mm; ΔX thorax = 5 mm; ΔZ thorax = 1 mm). Seat belt forces at the time of probabilistic failed region initiation were lower than those at deterministic failed region initiation. The probabilistic method for rib fracture predicted more failed regions in the rib (an analog for fracture) than the deterministic method in all but 1 case where they were equal. The failed region patterns between models are similar; however, there are differences that arise due to stress reduced from element elimination that cause probabilistic failed regions to continue to rise after no deterministic failed region would be

  17. Accessory caudal axial and pelvic ribs

    International Nuclear Information System (INIS)

    Bohutova, J.; Kolar, J.; Vitovec, J.; Vyhnanek, L.

    1980-01-01

    Accessory caudal ribs are reported as an extremely curious anomaly in five patients. Once the fracture of this rib was a source of pains after injury. The different shapes of the ribs are documented in this clinical survey which is the most extensive in the present literature. Anomalous ribs arise due to inappropriate segmentation during the embryonal development of the axial skeleton. (orig.) [de

  18. Rib Fractures

    Science.gov (United States)

    ... Video) Achilles Tendon Tear Additional Content Medical News Rib Fractures By Thomas G. Weiser, MD, MPH, Associate Professor, ... Tamponade Hemothorax Injury to the Aorta Pulmonary Contusion Rib Fractures Tension Pneumothorax Traumatic Pneumothorax (See also Introduction to ...

  19. Issues in Biological Shape Modelling

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen

    This talk reflects parts of the current research at informatics and Mathematical Modelling at the Technical University of Denmark within biological shape modelling. We illustrate a series of generalizations, modifications, and applications of the elements of constructing models of shape or appear......This talk reflects parts of the current research at informatics and Mathematical Modelling at the Technical University of Denmark within biological shape modelling. We illustrate a series of generalizations, modifications, and applications of the elements of constructing models of shape...

  20. Computed tomography measurement of rib cage morphometry in emphysema.

    Directory of Open Access Journals (Sweden)

    Nicola Sverzellati

    Full Text Available BACKGROUND: Factors determining the shape of the human rib cage are not completely understood. We aimed to quantify the contribution of anthropometric and COPD-related changes to rib cage variability in adult cigarette smokers. METHODS: Rib cage diameters and areas (calculated from the inner surface of the rib cage in 816 smokers with or without COPD, were evaluated at three anatomical levels using computed tomography (CT. CTs were analyzed with software, which allows quantification of total emphysema (emphysema%. The relationship between rib cage measurements and anthropometric factors, lung function indices, and %emphysema were tested using linear regression models. RESULTS: A model that included gender, age, BMI, emphysema%, forced expiratory volume in one second (FEV1%, and forced vital capacity (FVC% fit best with the rib cage measurements (R(2 = 64% for the rib cage area variation at the lower anatomical level. Gender had the biggest impact on rib cage diameter and area (105.3 cm(2; 95% CI: 111.7 to 98.8 for male lower area. Emphysema% was responsible for an increase in size of upper and middle CT areas (up to 5.4 cm(2; 95% CI: 3.0 to 7.8 for an emphysema increase of 5%. Lower rib cage areas decreased as FVC% decreased (5.1 cm(2; 95% CI: 2.5 to 7.6 for 10 percentage points of FVC variation. CONCLUSIONS: This study demonstrates that simple CT measurements can predict rib cage morphometric variability and also highlight relationships between rib cage morphometry and emphysema.

  1. Oriented active shape models.

    Science.gov (United States)

    Liu, Jiamin; Udupa, Jayaram K

    2009-04-01

    Active shape models (ASM) are widely employed for recognizing anatomic structures and for delineating them in medical images. In this paper, a novel strategy called oriented active shape models (OASM) is presented in an attempt to overcome the following five limitations of ASM: 1) lower delineation accuracy, 2) the requirement of a large number of landmarks, 3) sensitivity to search range, 4) sensitivity to initialization, and 5) inability to fully exploit the specific information present in the given image to be segmented. OASM effectively combines the rich statistical shape information embodied in ASM with the boundary orientedness property and the globally optimal delineation capability of the live wire methodology of boundary segmentation. The latter characteristics allow live wire to effectively separate an object boundary from other nonobject boundaries with similar properties especially when they come very close in the image domain. The approach leads to a two-level dynamic programming method, wherein the first level corresponds to boundary recognition and the second level corresponds to boundary delineation, and to an effective automatic initialization method. The method outputs a globally optimal boundary that agrees with the shape model if the recognition step is successful in bringing the model close to the boundary in the image. Extensive evaluation experiments have been conducted by utilizing 40 image (magnetic resonance and computed tomography) data sets in each of five different application areas for segmenting breast, liver, bones of the foot, and cervical vertebrae of the spine. Comparisons are made between OASM and ASM based on precision, accuracy, and efficiency of segmentation. Accuracy is assessed using both region-based false positive and false negative measures and boundary-based distance measures. The results indicate the following: 1) The accuracy of segmentation via OASM is considerably better than that of ASM; 2) The number of landmarks

  2. Ribbing disease

    International Nuclear Information System (INIS)

    Mukkada, Philson J; Franklin, Teenu; Rajeswaran, Rangasami; Joseph, Santhosh

    2010-01-01

    Ribbing disease is a rare sclerosing dysplasia that involves long tubular bones, especially the tibia and femur. It occurs after puberty and is reported to be more common in women. In this article we describe how Ribbing disease can be differentiated from diseases like Engelmann-Camurati disease, van Buchem disease, Erdheim-Chester disease, osteoid osteoma, chronic osteomyelitis, stress fracture, etc

  3. Influence of wall ribs on the thermal stratification and self-pressurization in a cryogenic liquid tank

    International Nuclear Information System (INIS)

    Fu, Juan; Sunden, Bengt; Chen, Xiaoqian

    2014-01-01

    Self-pressurization in a cylindrical ribbed tank which is partially filled with liquid hydrogen is investigated numerically under different rib spacing-to-height ratios. The Volume of Fluid (VOF) method is employed as well as a phase change model. Appropriate models are incorporated into the Ansys Fluent by the user-defined functions to carry out the computations. The ribbed surface is modeled as a finned surface and a conjugate transient heat transfer problem is formulated for predicting fluid flow currents and heat transfer. The effect of rib material and shapes is also studied. Numerical results indicate that the pressure rise can be reduced by ribs mounted on the tank wall. This phenomenon is more pronounced as the rib spacing-to-height ratio is reduced. A vortex is observed in the downstream region of each rib when the spacing-to-height has a relatively high value. Evaporation occurs as time elapses due to heat accumulation at the rib surfaces. Pressure starts to rise later with high thermal conductivity ribs and becomes higher with low thermal conductivity ribs when the ribs are of identical configuration in geometry. The final pressure rise seems to be monotonically versus increasing time. The semicircular ribs perform better than rectangular ones in control of the pressure rise and thermal stratification for identical cross sectional area and if the locations are kept the same

  4. Parameter survey of a rib stiffened wooden floor using sinus modes model

    DEFF Research Database (Denmark)

    Sjökvist, Lars-Göran; Brunskog, Jonas; Jacobsen, Finn

    2008-01-01

    of the sound insulation for lightweight buildings have the possibility to speed up the development of new techniques and in the end give tenants better quality of life. This study uses Fourier sinus series to calculate the vibrations on a rib stiffened plate. The beams are modelled as line forces and moments......In buildings built with new techniques there exists a need for better understanding of their acoustical performance. The development of large wooden houses slows down by the uncertainty and costly testing that have to be performed many times before gaining good results. A greater understanding...

  5. Experimental investigation of the effect of variously-shaped ribs on local heat transfer on the outer wall of the turning portion of a U-channel inside solar air heater

    Science.gov (United States)

    Salameh, Tareq; Alami, Abdul Hai; Sunden, Bengt

    2016-03-01

    In the present work, an experimental investigation of convective heat transfer and pressure drop was carried out for the turning portion of a U-channel where the outer wall was equipped with ribs. The shape of the ribs was varied. The investigation aims to give guidelines for improving the thermo-hydraulic performance of a solar air heater at the turning portion of a U-channel. Both the U-channel and the ribs were made in acrylic material to allow optical access for measuring the surface temperature by using a high-resolution technique based on narrow band thermochromic liquid crystals (TLC R35C5 W) and a CCD camera placed to face the turning portion of the U-channel. The uncertainties were estimated to 5 and 7 % for the Nusselt number and friction factor, respectively. The pressure drop was approximately the same for all the considered shapes of the ribs while the dimpled rib case gave the highest heat transfer coefficient while the grooved rib presented the highest performance index.

  6. A study of the rib fall mechanism in soft coal and its control at a fully-mechanized top-coal caving face

    Energy Technology Data Exchange (ETDEWEB)

    Fang Xin-qiu; He Jie; Li Hai-chao [China University of Mining & Technology, Xuzhou (China). School of Mines

    2009-05-15

    The factors involved in rib-fall at a fully-mechanized top-coal caving face in the Wuyang mine were analyzed. The mechanical stress characteristics and the mechanism of rib-fall were modeled. Control principles and methods were proposed and a control project, and parameters for it, was identified. An underground industrial scale test was subsequently completed. The results show that arc shaped 'sliding surfaces' exist in the rib. The critical height of stable areas is 1.8 meters. The key to rib stability is the control of this arc shaped surface. Wooden bolts are used in the serious rib-fall zone to stabilize the rib. After implementation of the new project rib fall depth and scope were reduced significantly and tip-to-face caving was effectively controlled. 10 refs., 5 figs.

  7. Pulsed ultrasounds accelerate healing of rib fractures in an experimental animal model: an effective new thoracic therapy?

    Science.gov (United States)

    Santana-Rodríguez, Norberto; Clavo, Bernardino; Fernández-Pérez, Leandro; Rivero, José C; Travieso, María M; Fiuza, María D; Villar, Jesús; García-Castellano, José M; Hernández-Pérez, Octavio; Déniz, Antonio

    2011-05-01

    Rib fractures are a frequent traumatic injury associated with a relatively high morbidity. Currently, the treatment of rib fractures is symptomatic. Since it has been reported that pulsed ultrasounds accelerates repair of limb fractures, we hypothesized that the application of pulsed ultrasounds will modify the course of healing in an animal model of rib fracture. We studied 136 male Sprague-Dawley rats. Animals were randomly assigned to different groups of doses (none, 50, 100, and 250 mW/cm(2) of intensity for 3 minutes per day) and durations (2, 10, 20, and 28 days) of treatment with pulsed ultrasounds. In every subgroup, we analyzed radiologic and histologic changes in the bone callus. In addition, we examined changes in gene expression of relevant genes involved in wound repair in both control and treated animals. Histologic and radiologic consolidation was significantly increased by pulsed ultrasound treatment when applied for more than 10 days. The application of 50 mW/cm(2) was the most effective dose. Only the 100 and 250 mW/cm(2) doses were able to significantly increase messenger RNA expression of insulin-like growth factor 1, suppressor of cytokine signaling-2 and -3, and vascular endothelial growth factor and decrease monocyte chemoattractant protein-1 and collagen type II-alpha 1. Our findings indicate that pulsed ultrasound accelerates the consolidation of rib fractures. This study is the first to show that pulsed ultrasound promotes the healing of rib fractures. From a translational point of view, this easy, cheap technique could serve as an effective new therapeutic modality in patients with rib fractures. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  8. Compressive rib fracture: peri-mortem and post-mortem trauma patterns in a pig model.

    Science.gov (United States)

    Kieser, Jules A; Weller, Sarah; Swain, Michael V; Neil Waddell, J; Das, Raj

    2013-07-01

    Despite numerous studies on high impact fractures of ribs, little is known about compressive rib injuries. We studied rib fractures from a biomechanical and morphological perspective using 15, 5th ribs of domestic pigs Sus scrofa, divided into two groups, desiccated (representing post-mortem trauma) and fresh ribs with intact periosteum (representing peri-mortem trauma). Ribs were axially compressed and subjected to four-point bending in an Instron 3339 fitted with custom jigs. Morphoscopic analysis of resultant fractures consisted of standard optical methods, micro-CT (μCT) and scanning electron microscopy (SEM). During axial compression, fresh ribs had slightly higher strength because of energy absorption capabilities of their soft and fluidic components. In flexure tests, dry ribs showed typical elastic-brittle behaviour with long linear load-extension curves, followed by relatively short non-linear elastic (hyperelastic) behaviour and brittle fracture. Fresh ribs showed initial linear-elastic behaviour, followed by strain softening, visco-plastic responses. During the course of loading, dry bone showed minimal observable damage prior to the onset of unstable fracture. In contrast, fresh bone showed buckling-like damage features on the compressive surface and cracking parallel to the axis of the bone. Morphologically, all dry ribs fractured precipitously, whereas all but one of the fresh ribs showed incomplete fracture. The mode of fracture, however, was remarkably similar for both groups, with butterfly fractures predominating (7/15, 46.6% dry and wet). Our study highlights the fact that under controlled loading, despite seemingly similar butterfly fracture morphology, fresh ribs (representing perimortem trauma) show a non-catastrophic response. While extensive strain softening observed for the fresh bone does show some additional micro-cracking damage, it appears that the periosteum may play a key role in imparting the observed pseudo-ductility to the ribs

  9. Women in Shape Modeling Workshop

    CERN Document Server

    Tari, Sibel

    2015-01-01

    Presenting the latest research from the growing field of mathematical shape analysis, this volume is comprised of the collaborations of participants of the Women in Shape Modeling (WiSh) workshop, held at UCLA's Institute for Pure and Applied Mathematics in July 2013. Topics include: Simultaneous spectral and spatial analysis of shape Dimensionality reduction and visualization of data in tree-spaces, such as classes of anatomical trees like airways and blood vessels Geometric shape segmentation, exploring shape segmentation from a Gestalt perspective, using information from the Blum medial axis of edge fragments in an image Representing and editing self-similar details on 3D shapes, studying shape deformation and editing techniques Several chapters in the book directly address the problem of continuous measures of context-dependent nearness and right shape models. Medical and biological applications have been a major source of motivation in shape research, and key topics are examined here in detail. All...

  10. Experimental and numerical analysis of interlocking rib formation at sheet metal blanking

    Science.gov (United States)

    Bolka, Špela; Bratuš, Vitoslav; Starman, Bojan; Mole, Nikolaj

    2018-05-01

    Cores for electrical motors are typically produced by blanking of laminations and then stacking them together, with, for instance, interlocking ribs or welding. Strict geometrical tolerances, both on the lamination and on the stack, combined with complex part geometry and harder steel strip material, call for use of predictive methods to optimize the process before actual blanking to reduce the costs and speed up the process. One of the major influences on the final stack geometry is the quality of the interlocking ribs. A rib is formed in one step and joined with the rib of the preceding lamination in the next. The quality of the joint determines the firmness of the stack and also influences its. The geometrical and positional accuracy is thus crucial in rib formation process. In this study, a complex experimental and numerical analysis of interlocking rib formation has been performed. The aim of the analysis is to numerically predict the shape of the rib in order to perform a numerical simulation of the stack formation in the next step of the process. A detailed experimental research has been performed in order to characterize influential parameters on the rib formation and the geometry of the ribs itself, using classical and 3D laser microscopy. The formation of the interlocking rib is then simulated using Abaqus Explicit. The Hilll 48 constitutive material model is based on extensive and novel material characterization process, combining data from in-plane and out-of-plane material tests to perform a 3D analysis of both, rib formation and rib joining. The study shows good correlation between the experimental and numerical results.

  11. Predicting Rib Fracture Risk With Whole-Body Finite Element Models: Development and Preliminary Evaluation of a Probabilistic Analytical Framework

    Science.gov (United States)

    Forman, Jason L.; Kent, Richard W.; Mroz, Krystoffer; Pipkorn, Bengt; Bostrom, Ola; Segui-Gomez, Maria

    2012-01-01

    This study sought to develop a strain-based probabilistic method to predict rib fracture risk with whole-body finite element (FE) models, and to describe a method to combine the results with collision exposure information to predict injury risk and potential intervention effectiveness in the field. An age-adjusted ultimate strain distribution was used to estimate local rib fracture probabilities within an FE model. These local probabilities were combined to predict injury risk and severity within the whole ribcage. The ultimate strain distribution was developed from a literature dataset of 133 tests. Frontal collision simulations were performed with the THUMS (Total HUman Model for Safety) model with four levels of delta-V and two restraints: a standard 3-point belt and a progressive 3.5–7 kN force-limited, pretensioned (FL+PT) belt. The results of three simulations (29 km/h standard, 48 km/h standard, and 48 km/h FL+PT) were compared to matched cadaver sled tests. The numbers of fractures predicted for the comparison cases were consistent with those observed experimentally. Combining these results with field exposure informantion (ΔV, NASS-CDS 1992–2002) suggests a 8.9% probability of incurring AIS3+ rib fractures for a 60 year-old restrained by a standard belt in a tow-away frontal collision with this restraint, vehicle, and occupant configuration, compared to 4.6% for the FL+PT belt. This is the first study to describe a probabilistic framework to predict rib fracture risk based on strains observed in human-body FE models. Using this analytical framework, future efforts may incorporate additional subject or collision factors for multi-variable probabilistic injury prediction. PMID:23169122

  12. Modelling of a DBR laser based on Raman effect in a silicon-on-insulator rib waveguide

    International Nuclear Information System (INIS)

    De Leonardis, Francesco; Dimastrodonato, Valeria; Passaro, Vittorio M N

    2008-01-01

    In this paper, third-order nonlinearities in silicon-on-insulator rib waveguides are investigated to obtain complete modelling, describing the behaviour of a stimulated Raman scattering based laser. The simulations of a distributed Bragg reflector laser operation in a time domain allow for the first time to study in detail the dependence of threshold and output powers on different device parameters. Both continuous wave and pulsed laser operations are theoretically demonstrated, as well as their dependence on device parameters

  13. How different are the Kebara 2 ribs to modern humans?

    Science.gov (United States)

    Chapman, Tara; Beyer, Benoît; Sholukha, Victor; Semal, Patrick; Feipel, Veronique; Louryan, Stéphane; Van Sint Jan, Serge

    2017-12-30

    This study analyses rib geometric parameters of individual ribs of 14 modern human subjects (7 males and 7 females) in comparison to the reconstructed ribs of the Kebara 2 skeleton which was taken from the reconstruction of a Neandertal thorax by Sawyer & Maley (2005). Three-dimensional (3D) models were segmented from CT scans and each rib vertex cloud was placed into a local coordinate system defined from the rib principal axes. Rib clouds were then analysed using best fitting ellipses of the external contours of the cross-section areas. The centroid of each ellipse was then used to measure the centroidal pathway between each slice (rib midline). Curvature of the ribs was measured from the mid-line of the ribs as the sum of angles between successive centroids in adjacent cross sections. Distinct common patterns were noted in all rib geometric parameters for modern humans. The Kebara 2 reconstructed ribs also followed the same patterns. This study demonstrated that there are differences between the sexes in rib geometrical parameters, with females showing smaller rib width, chord length and arc length, but greater curvature (rib torsion, rib axial curvature, rib anterior-posterior bending) than males. The Kebara 2 reconstructed ribs were within the modern human range for the majority of geometrical parameters.

  14. Statistical models of shape optimisation and evaluation

    CERN Document Server

    Davies, Rhodri; Taylor, Chris

    2014-01-01

    Deformable shape models have wide application in computer vision and biomedical image analysis. This book addresses a key issue in shape modelling: establishment of a meaningful correspondence between a set of shapes. Full implementation details are provided.

  15. Modelling of the acoustic field of a multi-element HIFU array scattered by human ribs

    Science.gov (United States)

    Gélat, Pierre; ter Haar, Gail; Saffari, Nader

    2011-09-01

    The efficacy of high-intensity focused ultrasound (HIFU) for the treatment of a range of different cancers, including those of the liver, prostate and breast, has been demonstrated. As a non-invasive focused therapy, HIFU offers considerable advantages over techniques such as chemotherapy and surgical resection in terms of reduced risk of harmful side effects. Despite this, there are a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the rib cage to induce tissue necrosis in the required volume whilst minimizing the formation of side lobes. Multi-element random-phased arrays are currently showing great promise in overcoming the limitations of single-element transducers. Nevertheless, successful treatment of a patient with liver tumours requires a thorough understanding of the way in which the ultrasonic pressure field from a HIFU array is scattered by the rib cage. In order to address this, a boundary element approach based on a generalized minimal residual (GMRES) implementation of the Burton-Miller formulation was used in conjunction with phase conjugation techniques to focus the field of a 256-element random HIFU array behind human ribs at locations requiring intercostal and transcostal treatment. Simulations were carried out on a 3D mesh of quadratic pressure patches generated using CT scan anatomical data for adult ribs 9-12 on the right side. The methodology was validated on spherical and cylindrical scatterers. Field calculations were also carried out for idealized ribs, consisting of arrays of strip-like scatterers, demonstrating effects of splitting at the focus. This method has the advantage of fully accounting for the effect of scattering and diffraction in 3D under continuous wave excitation.

  16. Modelling of the acoustic field of a multi-element HIFU array scattered by human ribs

    Energy Technology Data Exchange (ETDEWEB)

    Gelat, Pierre [National Physical Laboratory, Hampton Road, Teddington TW11 0LW (United Kingdom); Ter Haar, Gail [Therapeutic Ultrasound Group, Physics Department, Institute of Cancer Research, Sutton SM2 5NG (United Kingdom); Saffari, Nader, E-mail: Pierre.Gelat@npl.co.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom)

    2011-09-07

    The efficacy of high-intensity focused ultrasound (HIFU) for the treatment of a range of different cancers, including those of the liver, prostate and breast, has been demonstrated. As a non-invasive focused therapy, HIFU offers considerable advantages over techniques such as chemotherapy and surgical resection in terms of reduced risk of harmful side effects. Despite this, there are a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the rib cage to induce tissue necrosis in the required volume whilst minimizing the formation of side lobes. Multi-element random-phased arrays are currently showing great promise in overcoming the limitations of single-element transducers. Nevertheless, successful treatment of a patient with liver tumours requires a thorough understanding of the way in which the ultrasonic pressure field from a HIFU array is scattered by the rib cage. In order to address this, a boundary element approach based on a generalized minimal residual (GMRES) implementation of the Burton-Miller formulation was used in conjunction with phase conjugation techniques to focus the field of a 256-element random HIFU array behind human ribs at locations requiring intercostal and transcostal treatment. Simulations were carried out on a 3D mesh of quadratic pressure patches generated using CT scan anatomical data for adult ribs 9-12 on the right side. The methodology was validated on spherical and cylindrical scatterers. Field calculations were also carried out for idealized ribs, consisting of arrays of strip-like scatterers, demonstrating effects of splitting at the focus. This method has the advantage of fully accounting for the effect of scattering and diffraction in 3D under continuous wave excitation.

  17. Heat transfer and friction correlations for artificially roughened solar air heater duct with discrete W-shaped ribs

    International Nuclear Information System (INIS)

    Kumar, Arvind; Bhagoria, J.L.; Sarviya, R.M.

    2009-01-01

    An experimental investigation has been carried out to study the heat transfer and friction characteristics in solar air heater by using discrete W-shaped roughness on one broad wall of solar air heater with an aspect ratio of 8:1, the roughened wall being heated while the remaining three walls are insulated. The experiment encompassed Reynolds number (Re) range from 3000 to 15,000, relative roughness height (e/D h ) in the range of 0.0168-0.0338, relative roughness pitch (p/e) 10 and the angle of attack (α) in the range of 30-75 deg. The effect of parameters on the heat transfer and friction are compared with the result of smooth duct under similar flow conditions. Correlations for heat transfer and friction have been developed as a function of roughness and flow parameters.

  18. Tissue engineering rib with the incorporation of biodegradable polymer cage and BMSCs/decalcified bone: an experimental study in a canine model.

    Science.gov (United States)

    Tang, Hua; Wu, Bin; Qin, Xiong; Zhang, Lu; Kretlow, Jim; Xu, Zhifei

    2013-05-20

    The reconstruction of large bone defects, including rib defects, remains a challenge for surgeons. In this study, we used biodegradable polydioxanone (PDO) cages to tissue engineer ribs for the reconstruction of 4cm-long costal defects. PDO sutures were used to weave 6cm long and 1cm diameter cages. Demineralized bone matrix (DBM) which is a xenograft was molded into cuboids and seeded with second passage bone marrow mesenchymal stem cells (BMSCs) that had been osteogenically induced. Two DBM cuboids seeded with BMSCs were put into the PDO cage and used to reconstruct the costal defects. Radiographic examination including 3D reconstruction, histologic examination and mechanical test was performed after 24 postoperative weeks. All the experimental subjects survived. In all groups, the PDO cage had completely degraded after 24 weeks and been replaced by fibrous tissue. Better shape and radian were achieved in PDO cages filled with DBM and BMSCs than in the other two groups (cages alone, or cages filled with acellular DBM cuboids). When the repaired ribs were subjected to an outer force, the ribs in the PDO cage/DBMs/BMSCs group kept their original shape while ribs in the other two groups deformed. In the PDO cage/DBMs/BMSCs groups, we also observed bony union at all the construct interfaces while there was no bony union observed in the other two groups. This result was also confirmed by radiographic and histologic examination. This study demonstrates that biodegradable PDO cage in combination with two short BMSCs/DBM cuboids can repair large rib defects. The satisfactory repair rate suggests that this might be a feasible approach for large bone repair.

  19. Fluid dynamics of Ribbed Annuli

    International Nuclear Information System (INIS)

    McCreery, G. E.; Pink, R. J.; Condie, K. G.; McEligot, D. M.

    2003-01-01

    Typical advanced gas-cooled reactor designs use periodic spacer ribs to center rods in circular cooling channels, e.g., as for control rods (General Atomics and others) and fuel rods (HTTR). In contrast to classical studies of axisymmetric annuli, the flow becomes three-dimensional but is typically periodic in the circumferential direction and - in some cases - in the streamwise direction. Fundamental measurements have been obtained for two idealizations of these complex geometries: an annulus with three ribs circumferentially and one with four. Laser Doppler Velocimetry (LDV) was employed with INEEL's unique Matched-Index-of-Refraction (MIR) flow facility to determine the velocity and turbulence fields. The initial experiment was aimed at obtaining benchmark data to test the capabilities of CFD (Computational Fluid Dynamics) codes to handle ribbed annular geometries without the complications of turbulent transport. The Reynolds number was about 1120. These conditions correspond to some stages during a pressurized cooldown (LOFA) event. Power spectral densities were obtained to determine the eddy shedding frequency downstream of the ribs. For the second experiment LDV measurements were obtained in another ribbed-annular model at a higher flow rate. For this nominally turbulent flow, evidence of laminarization appears in the flow converging to pass between ribs. The measurements indicated flow details which could be useful for assessment of CFD codes

  20. Rib fracture - aftercare

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000539.htm Rib fracture - aftercare To use the sharing features on this page, please enable JavaScript. A rib fracture is a crack or break in one or ...

  1. Atraumatic First Rib Fracture

    OpenAIRE

    Koray Aydogdu

    2014-01-01

    Rib fractures are usually seen after a trauma, while atraumatic spontaneous rib fractures are quite rare. A first rib fracture identified in our 17 years old female patient who had not a history of trauma except lifting a heavy weight was examined in details in terms of the potential complications and followed-up for a long time. We presented our experience on this case with atraumatic first rib fracture that has different views for the etiology in light of the literature.

  2. Surgical rib fixation

    OpenAIRE

    Marasco, Silvana

    2017-01-01

    Traumatic rib fracture injuries are being seen with increasing frequency in the hospital setting. They are often associated with other severe injuries and frequently require admission. The most severe form of rib fracture injury, flail chest, has a mortality of up to 33%. Rib fracture injuries have also been associated with chronic pain, malunion, deformity, disability and poor quality of life. Despite this, the standard of management for rib fracture injuries was, and in most ...

  3. A statistical model for mapping morphological shape

    Directory of Open Access Journals (Sweden)

    Li Jiahan

    2010-07-01

    Full Text Available Abstract Background Living things come in all shapes and sizes, from bacteria, plants, and animals to humans. Knowledge about the genetic mechanisms for biological shape has far-reaching implications for a range spectrum of scientific disciplines including anthropology, agriculture, developmental biology, evolution and biomedicine. Results We derived a statistical model for mapping specific genes or quantitative trait loci (QTLs that control morphological shape. The model was formulated within the mixture framework, in which different types of shape are thought to result from genotypic discrepancies at a QTL. The EM algorithm was implemented to estimate QTL genotype-specific shapes based on a shape correspondence analysis. Computer simulation was used to investigate the statistical property of the model. Conclusion By identifying specific QTLs for morphological shape, the model developed will help to ask, disseminate and address many major integrative biological and genetic questions and challenges in the genetic control of biological shape and function.

  4. Shaping asteroid models using genetic evolution (SAGE)

    Science.gov (United States)

    Bartczak, P.; Dudziński, G.

    2018-02-01

    In this work, we present SAGE (shaping asteroid models using genetic evolution), an asteroid modelling algorithm based solely on photometric lightcurve data. It produces non-convex shapes, orientations of the rotation axes and rotational periods of asteroids. The main concept behind a genetic evolution algorithm is to produce random populations of shapes and spin-axis orientations by mutating a seed shape and iterating the process until it converges to a stable global minimum. We tested SAGE on five artificial shapes. We also modelled asteroids 433 Eros and 9 Metis, since ground truth observations for them exist, allowing us to validate the models. We compared the derived shape of Eros with the NEAR Shoemaker model and that of Metis with adaptive optics and stellar occultation observations since other models from various inversion methods were available for Metis.

  5. Thermomechanical macroscopic model of shape memory alloys

    International Nuclear Information System (INIS)

    Volkov, A.E.; Sakharov, V.Yu.

    2003-01-01

    The phenomenological macroscopic model of the mechanical behaviour of the titanium nickelide-type shape memory alloys is proposed. The model contains as a parameter the average phase shear deformation accompanying the martensite formation. It makes i possible to describe correctly a number of functional properties of the shape memory alloys, in particular, the pseudoelasticity ferroplasticity, plasticity transformation and shape memory effects in the stressed and unstressed samples [ru

  6. Atraumatic First Rib Fracture

    Directory of Open Access Journals (Sweden)

    Koray Aydogdu

    2014-12-01

    Full Text Available Rib fractures are usually seen after a trauma, while atraumatic spontaneous rib fractures are quite rare. A first rib fracture identified in our 17 years old female patient who had not a history of trauma except lifting a heavy weight was examined in details in terms of the potential complications and followed-up for a long time. We presented our experience on this case with atraumatic first rib fracture that has different views for the etiology in light of the literature.

  7. Optimizing rib width to height and rib spacing to deck plate thickness ratios in orthotropic decks

    Directory of Open Access Journals (Sweden)

    Abdullah Fettahoglu

    2016-12-01

    Full Text Available Orthotropic decks are composed of deck plate, ribs, and cross-beams and are frequently used in industry to span long distances, due to their light structures and load carrying capacities. Trapezoidal ribs are broadly preferred as longitudinal stiffeners in design of orthotropic decks. They supply the required stiffness to the orthotropic deck in traffic direction. Trapezoidal ribs are chosen in industrial applications because of their high torsional and buckling rigidity, less material and welding needs. Rib width, height, spacing, thickness of deck plate are important parameters for designing of orthotropic decks. In the scope of this study, rib width to height and rib spacing to deck plate thickness ratios are assessed by means of the stresses developed under different ratios of these parameters. For this purpose a FE-model of orthotropic bridge is generated, which encompasses the entire bridge geometry and conforms to recommendations given in Eurocode 3 Part 2. Afterwards necessary FE-analyses are performed to reveal the stresses developed under different rib width to height and rib spacing to deck plate thickness ratios. Based on the results obtained in this study, recommendations regarding these ratios are provided for orthotropic steel decks occupying trapezoidal ribs.

  8. Minimum Description Length Shape and Appearance Models

    DEFF Research Database (Denmark)

    Thodberg, Hans Henrik

    2003-01-01

    The Minimum Description Length (MDL) approach to shape modelling is reviewed. It solves the point correspondence problem of selecting points on shapes defined as curves so that the points correspond across a data set. An efficient numerical implementation is presented and made available as open s...

  9. Statistical shape and appearance models of bones.

    Science.gov (United States)

    Sarkalkan, Nazli; Weinans, Harrie; Zadpoor, Amir A

    2014-03-01

    When applied to bones, statistical shape models (SSM) and statistical appearance models (SAM) respectively describe the mean shape and mean density distribution of bones within a certain population as well as the main modes of variations of shape and density distribution from their mean values. The availability of this quantitative information regarding the detailed anatomy of bones provides new opportunities for diagnosis, evaluation, and treatment of skeletal diseases. The potential of SSM and SAM has been recently recognized within the bone research community. For example, these models have been applied for studying the effects of bone shape on the etiology of osteoarthritis, improving the accuracy of clinical osteoporotic fracture prediction techniques, design of orthopedic implants, and surgery planning. This paper reviews the main concepts, methods, and applications of SSM and SAM as applied to bone. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Shape descriptors for mode-shape recognition and model updating

    International Nuclear Information System (INIS)

    Wang, W; Mottershead, J E; Mares, C

    2009-01-01

    The most widely used method for comparing mode shapes from finite elements and experimental measurements is the Modal Assurance Criterion (MAC), which returns a single numerical value and carries no explicit information on shape features. New techniques, based on image processing (IP) and pattern recognition (PR) are described in this paper. The Zernike moment descriptor (ZMD), Fourier descriptor (FD), and wavelet descriptor (WD), presented in this article, are the most popular shape descriptors having properties that include efficiency of expression, robustness to noise, invariance to geometric transformation and rotation, separation of local and global shape features and computational efficiency. The comparison of mode shapes is readily achieved by assembling the shape features of each mode shape into multi-dimensional shape feature vectors (SFVs) and determining the distances separating them.

  11. Development of a socket-type rib coaptation device made of poly-L-lactide fibers: feasibility study in a canine model

    Science.gov (United States)

    Komatsu, Teruya; Sakaguchi, Yasuto; Muranishi, Yusuke; Yutaka, Yojiro; Date, Hiroshi; Nakamura, Tatsuo

    2018-01-01

    Background Costal coaptation pins made of poly-L-lactide (PLA) are clinically available for fixing surgically divided ribs. However, the clinical results of such rib fixation have not been completely satisfactory. We aimed to develop a new rib coaptation socket system and explore its clinical applicability. Methods We surgically divided three consecutive ribs of each beagle dog, and rib coaptation sockets were implanted to stabilize each rib. Fifteen 3-dimensional (3D)-printed and 30 PLA fiber knitted sockets were implanted in five and ten dogs, respectively, to stabilize the artificially divided ribs. Mechanical analysis of the sockets and radiographical examination of costal fixation were performed to evaluate the effectiveness of the newly developed socket system for rib stabilization. Results All 15 ribs with 3D-printed sockets had displaced 1 month after the operation. Three ribs in one dog with implanted PLA fiber knitted sockets were displaced radiographically after 1 month, and the grade of displacement remained unchanged after 6 months. The remaining 27 ribs fixed with PLA fiber knitted sockets did not show any displacement. Conclusions The PLA fiber knitted rib coaptation socket system was sufficiently durable for the stabilization of divided ribs with biocompatibility. This promising finding can be applied for clinical stabilization of divided ribs. PMID:29850125

  12. Effect of ribbed and smooth coolant cross-flow channel on film cooling

    International Nuclear Information System (INIS)

    Peng, Wei; Sun, Xiaokai; Jiang, Peixue; Wang, Jie

    2017-01-01

    Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

  13. Effect of ribbed and smooth coolant cross-flow channel on film cooling

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wei; Sun, Xiaokai [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China); Jiang, Peixue, E-mail: jiangpx@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Educations, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Wang, Jie [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2017-05-15

    Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

  14. Rib cage pain

    Science.gov (United States)

    ... any of the following: Bruised, cracked, or fractured rib Inflammation of cartilage near the ... the best cures for a ribcage fracture . Follow your health care provider's instructions for treating ...

  15. Spontaneous rib fractures.

    Science.gov (United States)

    Katrancioglu, Ozgur; Akkas, Yucel; Arslan, Sulhattin; Sahin, Ekber

    2015-07-01

    Other than trauma, rib fracture can occur spontaneously due to a severe cough or sneeze. In this study, patients with spontaneous rib fractures were analyzed according to age, sex, underlying pathology, treatment, and complications. Twelve patients who presented between February 2009 and February 2011 with spontaneous rib fracture were reviewed retrospectively. The patients' data were evaluated according to anamnesis, physical examination, and chest radiographs. The ages of the patients ranged from 34 to 77 years (mean 55.91 ± 12.20 years), and 7 (58.4%) were male. All patients had severe cough and chest pain. The fractures were most frequently between 4th and 9th ribs; multiple rib fractures were detected in 5 (41.7%) patients. Eight (66.7%) patients had chronic obstructive pulmonary disease, 2 (16.7%) had bronchial asthma, and 2 (16.7%) had osteoporosis. Bone densitometry revealed a high risk of bone fracture in all patients. Patients with chronic obstructive pulmonary disease or bronchial asthma had been treated with high-dose steroids for over a year. Spontaneous rib fracture due to severe cough may occur in patients with osteoporosis, chronic obstructive pulmonary disease, or bronchial asthma, receiving long-term steroid therapy. If these patients have severe chest pain, chest radiography should be performed to check for bone lesions. © The Author(s) 2015.

  16. RIBBED DOUBLE PIPE HEAT EXCHANGER: ANALYTICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    HUSSAIN H. AL-KAYIEM

    2011-02-01

    Full Text Available This paper presents the findings obtained by modeling a Double Pipe Heat Exchanger (DPHE equipped with repeated ribs from the inside for artificial roughing. An analytical procedure was developed to analyze the thermal and hydraulic performance of the DPHE with and without ribbing. The procedure was verified by comparing with experimental reported results and they are in good agreement. Several parameters were investigated in this study including the effect of ribs pitch to height ratios, P/e= 5, 10, 15, and 20, and ribs to hydraulic diameter ratios, e/Dh= 0.0595, 0.0765, and 0.107. These parameters were studied at various operating Reynolds number ranging from 2500 to 150000. Different installation configurations were investigated, too. An enhan-cement of 4 times in the heat transfer in terms of Stanton number was achieved at the expense of 38 times increase of pressure drop across the flow in terms of friction facto values.

  17. Conditional shape models for cardiac motion estimation

    DEFF Research Database (Denmark)

    Metz, Coert; Baka, Nora; Kirisli, Hortense

    2010-01-01

    We propose a conditional statistical shape model to predict patient specific cardiac motion from the 3D end-diastolic CTA scan. The model is built from 4D CTA sequences by combining atlas based segmentation and 4D registration. Cardiac motion estimation is, for example, relevant in the dynamic...

  18. Validation of a finite element human model for prediction of rib fractures

    NARCIS (Netherlands)

    Mordaka, J.K.; Meijer, R.; Rooij, L. van; Zmijewska, A.

    2007-01-01

    In the past, several crash test dummies were developed in order to measure forces acting on the human body during different loading conditions. However, they are limited in their biofidelity and their application type (frontal, lateral etc.). Recently, several numerical human models were developed.

  19. Cough-induced rib fractures.

    Science.gov (United States)

    Hanak, Viktor; Hartman, Thomas E; Ryu, Jay H

    2005-07-01

    To define the demographic, clinical, and radiological features of patients with cough-induced rib fractures and to assess potential risk factors. For this retrospective, single-center study, we identified all cases of cough-induced rib fractures diagnosed at the Mayo Clinic in Rochester, Minn, over a 9-year period between January 1, 1996, and January 31, 2005. Bone densitometry data from patients' medical records were analyzed, and T scores were used to classify patients into bone density categories. The mean +/- SD age of the 54 study patients at presentation was 55+/-17 years, and 42 patients (78%) were female. Patients presented with chest wall pain after onset of cough. Rib fracture was associated with chronic cough (> or =3 weeks' duration) in 85% of patients. Rib fractures were documented by chest radiography, rib radiography, computed tomography, or bone scan. Chest radiography had been performed in 52 patients and revealed rib fracture in 30 (58%). There were 112 fractured ribs in 54 patients. One half of patients had more than one fractured rib. Right-sided rib fractures alone were present in 17 patients (26 fractured ribs), left-sided in 23 patients (35 fractured ribs), and bilateral in 14 patients (51 fractured ribs). The most commonly fractured rib on both sides was rib 6. The fractures were most common at the lateral aspect of the rib cage. Bone densitometry was done in 26 patients and revealed osteopenia or osteoporosis in 17 (65%). Cough-induced rib fractures occur primarily in women with chronic cough. Middle ribs along the lateral aspect of the rib cage are affected most commonly. Although reduced bone density is likely a risk factor, cough-induced rib fractures can occur in the presence of normal bone density.

  20. Digital Modeling and Shaping of Design Practices

    DEFF Research Database (Denmark)

    Reijonen, Satu

    This paper focuses on the role of digital modeling in shaping coordinative practices between architects and energy engineers in construction design. The paper presents a case study of the use of an energy performance calculation programme, a numeric digital modeling tool, that not only enables...... coordination between the two communities but also shapes coordinative practices around the emerging building. The paper draws on two interlinked strands of literature that have engaged in the role of material artefacts in the social: the entanglement of technology in organizing and management (Orlikowski 2000......, 2010), and the socio-material constructivist studies of technology (Akrich 1992, Akrich et al. 2000, Latour 1991). The programme influences the coordinative practices in following ways: it shapes the modus of interaction between energy engineers and architects and enforces particular jurisdictional...

  1. Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels

    Science.gov (United States)

    Sivakumar, Karthikeyan; Kulasekharan, N.; Natarajan, E.

    2018-05-01

    Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.

  2. Bifid rib: A rare anomaly

    Directory of Open Access Journals (Sweden)

    Mythili Krishnan Rathinasabapathi

    2015-01-01

    Full Text Available A case of the bifid rib was found during routine bone study. The distal part of the osseous rib bifurcated into two divisions with an angle of 60°. Both divisions had their own costal cartilage. Bifid rib is a congenital abnormality of the rib cage and usually asymptomatic, often discovered incidentally on chest X-ray. Effects of this neuroskeletal anomaly can include respiratory difficulties and neurological limitations.

  3. Constitutive Models for Shape Memory Alloy Polycrystals

    Science.gov (United States)

    Comstock, R. J., Jr.; Somerday, M.; Wert, J. A.

    1996-01-01

    Shape memory alloys (SMA) exhibiting the superelastic or one-way effects can produce large recoverable strains upon application of a stress. In single crystals this stress and resulting strain are very orientation dependent. We show experimental stress/strain curves for a Ni-Al single crystal for various loading orientations. Also shown are model predictions; the open and closed circles indicate recoverable strains obtained at various stages in the transformation process. Because of the strong orientation dependence of shape memory properties, crystallographic texture can be expected to play an important role in the mechanical behavior of polycrystalline SMA. It is desirable to formulate a constitutive model to better understand and exploit the unique properties of SMA.

  4. Single crystalline silicon solar cells with rib structure

    Directory of Open Access Journals (Sweden)

    Shuhei Yoshiba

    2017-02-01

    Full Text Available To improve the conversion efficiency of Si solar cells, we have developed a thin Si wafer-based solar cell that uses a rib structure. The open-circuit voltage of a solar cell is known to increase with deceasing wafer thickness if the cell is adequately passivated. However, it is not easy to handle very thin wafers because they are brittle and are subject to warpage. We fabricated a lattice-shaped rib structure on the rear side of a thin Si wafer to improve the wafer’s strength. A silicon nitride film was deposited on the Si wafer surface and patterned to form a mask to fabricate the lattice-shaped rib, and the wafer was then etched using KOH to reduce the thickness of the active area, except for the rib region. Using this structure in a Si heterojunction cell, we demonstrated that a high open-circuit voltage (VOC could be obtained by thinning the wafer without sacrificing its strength. A wafer with thickness of 30 μm was prepared easily using this structure. We then fabricated Si heterojunction solar cells using these rib wafers, and measured their implied VOC as a function of wafer thickness. The measured values were compared with device simulation results, and we found that the measured VOC agrees well with the simulated results. To optimize the rib and cell design, we also performed device simulations using various wafer thicknesses and rib dimensions.

  5. Various appearances of rib companion shadow mimicking a pathologic condition

    International Nuclear Information System (INIS)

    Choi, Yo Won; Yoo, Shi Joon; Im, Jung Gil

    1992-01-01

    We have observed that the companion shadow of the upper rib may be misinterpreted as a small pneumothorax or pleural plaque associated with asbestosis. To observe the radiographic characteristics of the normal companion shadow, we analyzed, on the posteroanterior(PA) chest radiographs, the companion shadow of 50 normal cases. Factors such as occurrence on each rib, the sharpness of the margin, the relative position to the rib, the shape and the thickness were observed. Also, we analyzed the displaced pleura of 4 pneumothorax cases to differentiate their findings from the findings of normal companion shadows. On 50 normal chest radiographs, 192 companion shadows were observed on the first to fourth ribs. In 173 of those shadows, the visceral margin of the companion shadow on the second rib simulated pneumothorax more closely than those on any other ribs due to its apical location and thinness. In six of 50 normal cases, the companion shadow in the first or second rib showed an inwardly convex lower margin, mimicking pleural plaque. The companion shadow was suggested on the plain chest radiograph by the following characteristics imultiplicity (47/50), thicker than normal pleura (3/4), persistent on serial films with the same shape and specific location(4/4)

  6. Modeling of dispersion engineered chalcogenide rib waveguide for ultraflat mid-infrared supercontinuum generation in all-normal dispersion regime

    Science.gov (United States)

    Ahmad, H.; Karim, M. R.; Rahman, B. M. A.

    2018-03-01

    A rigorous numerical investigation has been carried out through dispersion engineering of chalcogenide rib waveguide for near-infrared to mid-infrared ultraflat broadband supercontinuum generation in all-normal group-velocity dispersion regime. We propose a novel design of a 1-cm-long air-clad rib waveguide which is made from {Ge}_{11.5} {As}_{24} {Se}_{64.5} chalcogenide glass as the core with either silica or {Ge}_{11.5} {As}_{24} {S}_{64.5} chalcogenide glass as a lower cladding separately. A broadband ultraflat supercontinuum spanning from 1300 to 1900 nm could be generated when pumped at 1.55 μ {m} with a low input peak power of 100 W. Shifting the pump to 2 μ {m}, the supercontinuum spectra extended in the mid-infrared region up to 3400 nm with a moderate-input peak power of 500 W. To achieve further extension in mid-infrared, we excite our optimized rib waveguide in both the anomalous and all-normal dispersion pumping regions at 3.1 μ {m} with a largest input peak power of 3 kW. In the case of anomalous dispersion region pumping, numerical analysis shows that supercontinuum spectrum can be extended in the mid-infrared up to 10 μ {m}, although this contains high spectral amplitude fluctuations over the entire bandwidth which limits the supercontinuum sources in the field of high precision measurement applications. On the other hand, by optimizing a rib waveguide geometry for pumping in all-normal dispersion region, we are able to generate a smooth and flat-top coherent supercontinuum spectrum with a moderate bandwidth spanning the wavelength range 2-5.5 μ {m} with less than 5 dB spectral fluctuation over the entire output bandwidth. Our proposed design is highly suitable for making on-chip SC light sources for a variety of applications such as biomedical imaging, and environmental and industrial sensing in the mid-infrared region.

  7. Cough-induced rib fractures.

    Science.gov (United States)

    Sano, Atsushi; Tashiro, Ken; Fukuda, Tsutomu

    2015-10-01

    Occasionally, patients who complain of chest pain after the onset of coughing are diagnosed with rib fractures. We investigated the characteristics of cough-induced rib fractures. Between April 2008 and December 2013, 17 patients were referred to our hospital with chest pain after the onset of coughing. Rib radiography was performed, focusing on the location of the chest pain. When the patient had other signs and symptoms such as fever or persistent cough, computed tomography of the chest was carried out. We analyzed the data retrospectively. Rib fractures were found in 14 of the 17 patients. The age of the patients ranged from 14 to 86 years (median 39.5 years). Ten patients were female and 4 were male. Three patients had chronic lung disease. There was a single rib fracture in 9 patients, and 5 had two or more fractures. The middle and lower ribs were the most commonly involved; the 10th rib was fractured most frequently. Cough-induced rib fractures occur in every age group regardless of the presence or absence of underlying disease. Since rib fractures often occur in the lower and middle ribs, rib radiography is useful for diagnosis. © The Author(s) 2015.

  8. Determinants of rib motion in flail chest.

    Science.gov (United States)

    Cappello, M; Legrand, A; De Troyer, A

    1999-03-01

    We have previously developed a canine model of isolated flail chest to assess the effects of this condition on the mechanics of breathing, and these studies have led to the conclusion that the respiratory displacement of the fractured ribs is primarily determined by the fall in pleural pressure (Delta Ppl) and the action of the parasternal intercostal muscles. The present studies were designed to test the validity of this conclusion. A flail was induced in six supine anesthetized animals by fracturing both dorsally and ventrally the second to fifth ribs on the right side of the chest, after which the phrenic nerve roots were bilaterally sectioned in the neck. Sectioning the phrenic nerves caused a 34% decrease in Delta Ppl, associated with a 39% increase in parasternal intercostal inspiratory EMG activity (p Delta Ppl during the subsequent inspiration, all animals again showed a clear-cut inward rib displacement. These observations therefore confirm that in dogs with flail chest, the inspiratory displacement of the fractured ribs is set by the balance between the force related to pleural pressure and that generated by the parasternal intercostals. These observations also point to the critical importance of the pattern of inspiratory muscle activation in determining the magnitude of rib cage paradox in such patients.

  9. New technique for fixing rib fracture with bioabsorbable plate.

    Science.gov (United States)

    Oyamatsu, Hironori; Ohata, Norihisa; Narita, Kunio

    2016-09-01

    Fixation of a bone fracture with a bioabsorbable plate made of poly-L-lactide and hydroxyapatite has received attention. We adopted this technique for a rib fracture by bending the plate into a U-shape and fixing it with suture through the holes in the mesh of the plate and holes that are drilled in the edge of the fractured rib. The suture is also wound around the plate. © The Author(s) 2016.

  10. Heat Transfer and Friction Studies in a Tilted and Rib-Roughened Trailing-Edge Cooling Cavity with and without the Trailing-Edge Cooling Holes

    Directory of Open Access Journals (Sweden)

    M. E. Taslim

    2014-01-01

    Full Text Available Local and average heat transfer coefficients and friction factors were measured in a test section simulating the trailing-edge cooling cavity of a turbine airfoil. The test rig with a trapezoidal cross-sectional area was rib-roughened on two opposite sides of the trapezoid (airfoil pressure and suction sides with tapered ribs to conform to the cooling cavity shape and had a 22-degree tilt in the flow direction upstream of the ribs that affected the heat transfer coefficients on the two rib-roughened surfaces. The radial cooling flow traveled from the airfoil root to the tip while exiting through 22 cooling holes along the airfoil trailing-edge. Two rib geometries, with and without the presence of the trailing-edge cooling holes, were examined. The numerical model contained the entire trailing-edge channel, ribs, and trailing-edge cooling holes to simulate exactly the tested geometry. A pressure-correction based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. Realizable k-ε turbulence model in conjunction with enhanced wall treatment approach for the near wall regions was used for turbulence closure. The applied thermal boundary conditions to the CFD models matched the test boundary conditions. Comparisons are made between the experimental and numerical results.

  11. Modeling shape selection of buckled dielectric elastomers

    Science.gov (United States)

    Langham, Jacob; Bense, Hadrien; Barkley, Dwight

    2018-02-01

    A dielectric elastomer whose edges are held fixed will buckle, given a sufficiently applied voltage, resulting in a nontrivial out-of-plane deformation. We study this situation numerically using a nonlinear elastic model which decouples two of the principal electrostatic stresses acting on an elastomer: normal pressure due to the mutual attraction of oppositely charged electrodes and tangential shear ("fringing") due to repulsion of like charges at the electrode edges. These enter via physically simplified boundary conditions that are applied in a fixed reference domain using a nondimensional approach. The method is valid for small to moderate strains and is straightforward to implement in a generic nonlinear elasticity code. We validate the model by directly comparing the simulated equilibrium shapes with the experiment. For circular electrodes which buckle axisymetrically, the shape of the deflection profile is captured. Annular electrodes of different widths produce azimuthal ripples with wavelengths that match our simulations. In this case, it is essential to compute multiple equilibria because the first model solution obtained by the nonlinear solver (Newton's method) is often not the energetically favored state. We address this using a numerical technique known as "deflation." Finally, we observe the large number of different solutions that may be obtained for the case of a long rectangular strip.

  12. Nineth Rib Syndrome after 10(th) Rib Resection.

    Science.gov (United States)

    Yu, Hyun Jeong; Jeong, Yu Sub; Lee, Dong Hoon; Yim, Kyoung Hoon

    2016-07-01

    The 12(th) rib syndrome is a disease that causes pain between the upper abdomen and the lower chest. It is assumed that the impinging on the nerves between the ribs causes pain in the lower chest, upper abdomen, and flank. A 74-year-old female patient visited a pain clinic complaining of pain in her back, and left chest wall at a 7 on the 0-10 Numeric Rating scale (NRS). She had a lateral fixation at T12-L2, 6 years earlier. After the operation, she had multiple osteoporotic compression fractures. When the spine was bent, the patient complained about a sharp pain in the left mid-axillary line and radiating pain toward the abdomen. On physical examination, the 10(th) rib was not felt, and an image of the rib-cage confirmed that the left 10(th) rib was severed. When applying pressure from the legs to the 9(th) rib of the patient, pain was reproduced. Therefore, the patient was diagnosed with 9(th) rib syndrome, and ultrasound-guided 9(th) and 10(th) intercostal nerve blocks were performed around the tips of the severed 10(th) rib. In addition, local anesthetics with triamcinolone were administered into the muscles beneath the 9(th) rib at the point of the greatest tenderness. The patient's pain was reduced to NRS 2 point. In this case, it is suspected that the patient had a partial resection of the left 10(th) rib in the past, and subsequent compression fractures at T8 and T9 led to the deformation of the rib cage, causing the tip of the remaining 10(th) rib to impinge on the 9(th) intercostal nerves, causing pain.

  13. Using a Shape Model in the Design of Hearing Aids

    DEFF Research Database (Denmark)

    Paulsen, Rasmus Reinhold; Nielsen, Claus; Laugesen, Søren

    2004-01-01

    shapes by a skilled operator. These faceplate planes are aligned to the average shape from the shape model and an average faceplate plane is calculated. Given a surface representation of a new ear canal, the shape model is fitted using a combination of the iterative closest point algorithm and the active...... shape model approach. The average faceplate from the training set can now be placed on the new ear canal using the position of the fitted shape model. A leave-one-out study shows that the algorithm is able to produce results comparable to a human operator....

  14. Airfoil Shape Optimization based on Surrogate Model

    Science.gov (United States)

    Mukesh, R.; Lingadurai, K.; Selvakumar, U.

    2018-02-01

    Engineering design problems always require enormous amount of real-time experiments and computational simulations in order to assess and ensure the design objectives of the problems subject to various constraints. In most of the cases, the computational resources and time required per simulation are large. In certain cases like sensitivity analysis, design optimisation etc where thousands and millions of simulations have to be carried out, it leads to have a life time of difficulty for designers. Nowadays approximation models, otherwise called as surrogate models (SM), are more widely employed in order to reduce the requirement of computational resources and time in analysing various engineering systems. Various approaches such as Kriging, neural networks, polynomials, Gaussian processes etc are used to construct the approximation models. The primary intention of this work is to employ the k-fold cross validation approach to study and evaluate the influence of various theoretical variogram models on the accuracy of the surrogate model construction. Ordinary Kriging and design of experiments (DOE) approaches are used to construct the SMs by approximating panel and viscous solution algorithms which are primarily used to solve the flow around airfoils and aircraft wings. The method of coupling the SMs with a suitable optimisation scheme to carryout an aerodynamic design optimisation process for airfoil shapes is also discussed.

  15. Analyses and Comparison of Solar Air Heater with Various Rib Roughness using Computational Fluid Dynamics (CFD)

    Science.gov (United States)

    Kumar, K. Ravi; Cheepu, Muralimohan; Srinivas, B.; Venkateswarlu, D.; Pramod Kumar, G.; Shiva, Apireddi

    2018-03-01

    In solar air heater, artificial roughness on absorber plate become prominent technique to improving heat transfer rate of air flowing passage as a result of laminar sublayer. The selection of rib geometries plays important role on friction characteristics and heat transfer rate. Many researchers studying the roughness shapes over the years to investigate the effect of geometries on the performance of friction factor and heat transfer of the solar air heater. The present study made an attempt to develop the different rib shapes utilised for creating artificial rib roughness and its comparison to investigate higher performance of the geometries. The use of computational fluid dynamics software resulted in correlation of friction factor and heat transfer rate. The simulations studies were performed on 2D computational fluid dynamics model and analysed to identify the most effective parameters of relative roughness of the height, width and pitch on major considerations of friction factor and heat transfer. The Reynolds number is varied in a range from 3000 to 20000, in the current study and modelling has conducted on heat transfer and turbulence phenomena by using Reynolds number. The modelling results showed the formation of strong vortex in the main stream flow due to the right angle triangle roughness over the square, rectangle, improved rectangle and equilateral triangle geometries enhanced the heat transfer extension in the solar air heater. The simulation of the turbulence kinetic energy of the geometry suggests the local turbulence kinetic energy has been influenced strongly by the alignments of the right angle triangle.

  16. Modeling the Creep of Rib-Reinforced Composite Media Made from Nonlinear Hereditary Phase Materials 2. Verification of the Model

    Science.gov (United States)

    Yankovskii, A. P.

    2015-05-01

    An indirect verification of a structural model describing the creep of a composite medium reinforced by honeycombs and made of nonlinear hereditary phase materials obeying the Rabotnov theory of creep is presented. It is shown that the structural model proposed is trustworthy and can be used in practical calculations. For different kinds of loading, creep curves for a honeycomb core made of a D16T aluminum alloy are calculated.

  17. Micromechanical modelling of shape memory alloy composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.F.; Wang, X.M.; Yue, Z.F. [School of Mechanic, Civil Engineering and Architecture, Northwestern Polytechnical University, Xian, 710072 (China)

    2004-03-01

    An isothermal finite element method (FEM) model has been applied to study the behavior of two kinds of shape memory alloy (SMA) composites. For SMA-fiber reinforced normal metal composites, the FEM analysis shows that the mechanical behavior of the composites depends on the SMA volume fraction. For normal metal-fiber reinforced SMA matrix composites, the SMA phase transformation is affected by the increasing Young's modulus of the metal fiber. The phase transformation was also treated using a simple numerical analysis, which assumes that there are uniform stresses and strains distributions in the fiber and the matrix respectively. It is found that there is an obvious difference between the FEM analysis and the simple numerical assessment. Only FEM can provide reasonable predictions of phase transformations in SMA/normal metal composites. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  18. Microplane modelling of shape memory alloys

    International Nuclear Information System (INIS)

    Kadkhodaei, M; Salimi, M; Rajapakse, R K N D; Mahzoon, M

    2007-01-01

    A three-dimensional (3D) constitutive model based on a statically constrained microplane theory with volumetric-deviatoric split is proposed for polycrystalline shape memory alloys (SMAs) under multiaxial loading paths. Microplane governing equations are 1D stress-strain relations for normal and shear stresses on each microplane, in which suitable relationships between the microscopic and macroscopic quantities are considered so that switching between elastic and inelastic local responses automatically occurs according to the macroscopic response of SMA without additional constraint. Shear stress on each microplane is expressed by the resultant shear component within the plane to overcome directional bias and to prevent the appearance of shear strain in a pure axial loading or axial strain in a pure shear loading while microplane formulations based on two shear directions may predict such impractical results. The behaviour of SMA under simple and complicated loadings has been studied. In nonproportional loading paths, the model shows interaction between stress components, as well as deviation from normality. Predicted results from the model are in good agreement with those of the existing theoretical and experimental investigations

  19. 3D shape decomposition and comparison for gallbladder modeling

    Science.gov (United States)

    Huang, Weimin; Zhou, Jiayin; Liu, Jiang; Zhang, Jing; Yang, Tao; Su, Yi; Law, Gim Han; Chui, Chee Kong; Chang, Stephen

    2011-03-01

    This paper presents an approach to gallbladder shape comparison by using 3D shape modeling and decomposition. The gallbladder models can be used for shape anomaly analysis and model comparison and selection in image guided robotic surgical training, especially for laparoscopic cholecystectomy simulation. The 3D shape of a gallbladder is first represented as a surface model, reconstructed from the contours segmented in CT data by a scheme of propagation based voxel learning and classification. To better extract the shape feature, the surface mesh is further down-sampled by a decimation filter and smoothed by a Taubin algorithm, followed by applying an advancing front algorithm to further enhance the regularity of the mesh. Multi-scale curvatures are then computed on the regularized mesh for the robust saliency landmark localization on the surface. The shape decomposition is proposed based on the saliency landmarks and the concavity, measured by the distance from the surface point to the convex hull. With a given tolerance the 3D shape can be decomposed and represented as 3D ellipsoids, which reveal the shape topology and anomaly of a gallbladder. The features based on the decomposed shape model are proposed for gallbladder shape comparison, which can be used for new model selection. We have collected 19 sets of abdominal CT scan data with gallbladders, some shown in normal shape and some in abnormal shapes. The experiments have shown that the decomposed shapes reveal important topology features.

  20. Simple Parametric Model for Airfoil Shape Description

    Science.gov (United States)

    Ziemkiewicz, David

    2017-12-01

    We show a simple, analytic equation describing a class of two-dimensional shapes well suited for representation of aircraft airfoil profiles. Our goal was to create a description characterized by a small number of parameters with easily understandable meaning, providing a tool to alter the shape with optimization procedures as well as manual tweaks by the designer. The generated shapes are well suited for numerical analysis with 2D flow solving software such as XFOIL.

  1. Chondroblastoma of rib : case report

    International Nuclear Information System (INIS)

    Kim, Dong Hun; Kim, Kyung Rae; Ryu, Sang Wan

    2004-01-01

    Chondroblastoma is an uncommon, benign, cartilaginous neoplasm originating in an epiphysis or apophysis of a long tubular bone. The rib is an unusual site for chondroblastoma. The authors describe a case of chondroblastoma of the rib and present a brief review of the literature

  2. Chondroblastoma of rib : case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Hun; Kim, Kyung Rae; Ryu, Sang Wan [Kwangju Hospital, Kwangju (Korea, Republic of)

    2004-07-01

    Chondroblastoma is an uncommon, benign, cartilaginous neoplasm originating in an epiphysis or apophysis of a long tubular bone. The rib is an unusual site for chondroblastoma. The authors describe a case of chondroblastoma of the rib and present a brief review of the literature.

  3. Shape prior modeling using sparse representation and online dictionary learning.

    Science.gov (United States)

    Zhang, Shaoting; Zhan, Yiqiang; Zhou, Yan; Uzunbas, Mustafa; Metaxas, Dimitris N

    2012-01-01

    The recently proposed sparse shape composition (SSC) opens a new avenue for shape prior modeling. Instead of assuming any parametric model of shape statistics, SSC incorporates shape priors on-the-fly by approximating a shape instance (usually derived from appearance cues) by a sparse combination of shapes in a training repository. Theoretically, one can increase the modeling capability of SSC by including as many training shapes in the repository. However, this strategy confronts two limitations in practice. First, since SSC involves an iterative sparse optimization at run-time, the more shape instances contained in the repository, the less run-time efficiency SSC has. Therefore, a compact and informative shape dictionary is preferred to a large shape repository. Second, in medical imaging applications, training shapes seldom come in one batch. It is very time consuming and sometimes infeasible to reconstruct the shape dictionary every time new training shapes appear. In this paper, we propose an online learning method to address these two limitations. Our method starts from constructing an initial shape dictionary using the K-SVD algorithm. When new training shapes come, instead of re-constructing the dictionary from the ground up, we update the existing one using a block-coordinates descent approach. Using the dynamically updated dictionary, sparse shape composition can be gracefully scaled up to model shape priors from a large number of training shapes without sacrificing run-time efficiency. Our method is validated on lung localization in X-Ray and cardiac segmentation in MRI time series. Compared to the original SSC, it shows comparable performance while being significantly more efficient.

  4. Fourier Series, the DFT and Shape Modelling

    DEFF Research Database (Denmark)

    Skoglund, Karl

    2004-01-01

    This report provides an introduction to Fourier series, the discrete Fourier transform, complex geometry and Fourier descriptors for shape analysis. The content is aimed at undergraduate and graduate students who wish to learn about Fourier analysis in general, as well as its application to shape...

  5. A probabilistic model for component-based shape synthesis

    KAUST Repository

    Kalogerakis, Evangelos

    2012-07-01

    We present an approach to synthesizing shapes from complex domains, by identifying new plausible combinations of components from existing shapes. Our primary contribution is a new generative model of component-based shape structure. The model represents probabilistic relationships between properties of shape components, and relates them to learned underlying causes of structural variability within the domain. These causes are treated as latent variables, leading to a compact representation that can be effectively learned without supervision from a set of compatibly segmented shapes. We evaluate the model on a number of shape datasets with complex structural variability and demonstrate its application to amplification of shape databases and to interactive shape synthesis. © 2012 ACM 0730-0301/2012/08-ART55.

  6. The role of acoustic nonlinearity in tissue heating behind a rib cage using a high-intensity focused ultrasound phased array

    Science.gov (United States)

    Yuldashev, Petr V.; Shmeleva, Svetlana M.; Ilyin, Sergey A.; Sapozhnikov, Oleg A.; Gavrilov, Leonid R.; Khokhlova, Vera A.

    2013-04-01

    The goal of this study was to investigate theoretically the effects of nonlinear propagation in a high-intensity focused ultrasound (HIFU) field produced by a therapeutic phased array and the resultant heating of tissue behind a rib cage. Three configurations of focusing were simulated: in water, in water with ribs in the beam path and in water with ribs backed by a layer of soft tissue. The Westervelt equation was used to model the nonlinear HIFU field, and a 1 MHz phased array consisting of 254 circular elements was used as a boundary condition to the model. The temperature rise in tissue was modelled using the bioheat equation, and thermally necrosed volumes were calculated using the thermal dose formulation. The shapes of lesions predicted by the modelling were compared with those previously obtained in in vitro experiments at low-power sonications. Intensity levels at the face of the array elements that corresponded to the formation of high-amplitude shock fronts in the focal region were determined as 10 W cm-2 in the free field in water and 40 W cm-2 in the presence of ribs. It was shown that exposures with shocks provided a substantial increase in tissue heating, and its better spatial localization in the main focal region only. The relative effects of overheating ribs and splitting of the focus due to the periodic structure of the ribs were therefore reduced. These results suggest that utilizing nonlinear propagation and shock formation effects can be beneficial for inducing confined HIFU lesions when irradiating through obstructions such as ribs. Design of compact therapeutic arrays to provide maximum power outputs with lower intensity levels at the elements is necessary to achieve shock wave regimes for clinically relevant sonication depths in tissue.

  7. Modeling the shape hierarchy for visually guided grasping

    CSIR Research Space (South Africa)

    Rezai, O

    2014-10-01

    Full Text Available The monkey anterior intraparietal area (AIP) encodes visual information about three-dimensional object shape that is used to shape the hand for grasping. We modeled shape tuning in visual AIP neurons and its relationship with curvature and gradient...

  8. Modeling self-occlusions in dynamic shape and appearance tracking

    KAUST Repository

    Yang, Yanchao; Sundaramoorthi, Ganesh

    2013-01-01

    We present a method to track the precise shape of a dynamic object in video. Joint dynamic shape and appearance models, in which a template of the object is propagated to match the object shape and radiance in the next frame, are advantageous over

  9. Adding Curvature to Minimum Description Length Shape Models

    DEFF Research Database (Denmark)

    Thodberg, Hans Henrik; Ólafsdóttir, Hildur

    2003-01-01

    The Minimum Description Length (MDL) approach to shape modelling seeks a compact description of a set of shapes in terms of the coordinates of marks on the shapes. It has been shown that the mark positions resulting from this optimisation to a large extent solve the so-called point correspondence...

  10. Shape optimization in biomimetics by homogenization modelling

    International Nuclear Information System (INIS)

    Hoppe, Ronald H.W.; Petrova, Svetozara I.

    2003-08-01

    Optimal shape design of microstructured materials has recently attracted a great deal of attention in material science. The shape and the topology of the microstructure have a significant impact on the macroscopic properties. The present work is devoted to the shape optimization of new biomorphic microcellular ceramics produced from natural wood by biotemplating. We are interested in finding the best material-and-shape combination in order to achieve the optimal prespecified performance of the composite material. The computation of the effective material properties is carried out using the homogenization method. Adaptive mesh-refinement technique based on the computation of recovered stresses is applied in the microstructure to find the homogenized elasticity coefficients. Numerical results show the reliability of the implemented a posteriori error estimator. (author)

  11. Dynamic shape transitions in the sdg boson model

    International Nuclear Information System (INIS)

    Kuyucak, S.

    1992-01-01

    The dynamic evolution of shapes in the sdg interacting boson model is investigated using the angular momentum projected mean field theory. Deformed nuclei are found to be quite stable against shape changes but transitional nuclei could exhibit dynamic shape transitions in the region L = 10-20. Conditions of existence and experimental signatures for dynamic shape transitions are discussed together with a likely candidate, 192 Os. 13 refs., 3 figs

  12. Dynamic shape transitions in the sdg boson model

    Science.gov (United States)

    Kuyucak, S.

    The dynamic evolution of shapes in the sdg interacting boson model is investigated using the angular momentum projected mean field theory. Deformed nuclei are found to be quite stable against shape changes but transitional nuclei could exhibit dynamic shape transitions in the region L = 10-20. Conditions of existence and experimental signatures for dynamic shape transitions are discussed together with a likely candidate, 192Os.

  13. Dynamic shape transitions in the sdg boson model

    Energy Technology Data Exchange (ETDEWEB)

    Kuyucak, S. (Melbourne Univ., Parkville (Australia). School of Physics)

    1992-01-01

    The dynamic evolution of shapes in the sdg interacting bosun model is investigated using the angular momentum projected mean field theory. Deformed nuclei are found to be quite stable against shape changes but transitional nuclei could exhibit dynamic shape transitions in the region L = 10-20. Conditions of existence and experimental signatures for dynamic shape transitions are discussed together with a likely candidate, {sup 192}Os. (author).

  14. Some Issues of Biological Shape Modelling with Applications

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Hilger, Klaus Baggesen; Skoglund, Karl

    2003-01-01

    This paper illustrates current research at Informatics and Mathematical Modelling at the Technical University of Denmark within biological shape modelling. We illustrate a series of generalizations to, modifications to, and applications of the elements of constructing models of shape or appearance...

  15. Modeling the relationship between scanned rump and 12th-rib fat in young temperate and tropical bovines: model development and evaluation.

    Science.gov (United States)

    Walmsley, B J; Wolcott, M L; McPhee, M J

    2010-05-01

    A decision support tool for predicting subcutaneous fat depths called BeefSpecs, based on the Davis growth model (DGM), has been developed by the Cooperative Research Centre for Beef Genetic Technologies. Currently, the DGM predicts 12th-rib fat thickness (RFT, mm). To allow predictions of fat thickness at the P8 rump (P8FT, mm) site, the standard carcass fat measurement in the Australian beef industry, a relationship was developed between ultrasound RFT and P8FT in steers and heifers from temperate (Angus, Hereford, Shorthorn, and Murray Grey) and tropical (Brahman, Belmont Red, and Santa Gertrudis) breed types. Model development involved fitting various combinations of sex, breed type (BrT), BW, age, and RFT to produce 6 models. The models were challenged with data from 3 independent data sets: 1) Angus steers from 2.4 generations of divergent selection for and against residual feed intake; 2) 2 tropically adapted genotypes [Brahman and tropically adapted composites (combinations of Belmont Red, Charbray, Santa Gertrudis, Senepol, and Brahman breeds)]; and 3) a study using sires from Charolais, Limousin, Belgian Blue, and Black and Red Wagyu breeds and 3 genetic lines of Angus to create divergence in progeny in terms of genetic potential for intramuscular fat percent and retail beef yield. When challenged with data from Angus cattle, the mean biases (MB, mm) for models A to F were -1.23, -0.56, -0.56, -0.02, 0.14, and 0.04, and the root mean square errors of predictions (mm) were 1.53, 0.97, 0.97, 0.92, 0.93, and 0.91, respectively. When challenged with data from Brahman cattle, MB were 0.04, -0.22, -0.14, 0.05, -0.11, and 0.02 and root mean square errors of predictions were 1.30, 1.29, 1.27, 1.23, 1.37, and 1.29, respectively. Generally, model accuracy indicated by MB tended to be less for model E, which contained age rather than BW as a covariate. Models B and C were generally robust when challenged with data from Angus, Brahman, and Tropical Composite cattle

  16. Objective models of compressed breast shapes undergoing mammography

    Science.gov (United States)

    Feng, Steve Si Jia; Patel, Bhavika; Sechopoulos, Ioannis

    2013-01-01

    Purpose: To develop models of compressed breasts undergoing mammography based on objective analysis, that are capable of accurately representing breast shapes in acquired clinical images and generating new, clinically realistic shapes. Methods: An automated edge detection algorithm was used to catalogue the breast shapes of clinically acquired cranio-caudal (CC) and medio-lateral oblique (MLO) view mammograms from a large database of digital mammography images. Principal component analysis (PCA) was performed on these shapes to reduce the information contained within the shapes to a small number of linearly independent variables. The breast shape models, one of each view, were developed from the identified principal components, and their ability to reproduce the shape of breasts from an independent set of mammograms not used in the PCA, was assessed both visually and quantitatively by calculating the average distance error (ADE). Results: The PCA breast shape models of the CC and MLO mammographic views based on six principal components, in which 99.2% and 98.0%, respectively, of the total variance of the dataset is contained, were found to be able to reproduce breast shapes with strong fidelity (CC view mean ADE = 0.90 mm, MLO view mean ADE = 1.43 mm) and to generate new clinically realistic shapes. The PCA models based on fewer principal components were also successful, but to a lesser degree, as the two-component model exhibited a mean ADE = 2.99 mm for the CC view, and a mean ADE = 4.63 mm for the MLO view. The four-component models exhibited a mean ADE = 1.47 mm for the CC view and a mean ADE = 2.14 mm for the MLO view. Paired t-tests of the ADE values of each image between models showed that these differences were statistically significant (max p-value = 0.0247). Visual examination of modeled breast shapes confirmed these results. Histograms of the PCA parameters associated with the six principal components were fitted with Gaussian distributions. The six

  17. Objective models of compressed breast shapes undergoing mammography

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Steve Si Jia [Department of Biomedical Engineering, Georgia Institute of Technology and Emory University and Department of Radiology and Imaging Sciences, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States); Patel, Bhavika [Department of Radiology and Imaging Sciences, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States); Sechopoulos, Ioannis [Departments of Radiology and Imaging Sciences, Hematology and Medical Oncology and Winship Cancer Institute, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States)

    2013-03-15

    Purpose: To develop models of compressed breasts undergoing mammography based on objective analysis, that are capable of accurately representing breast shapes in acquired clinical images and generating new, clinically realistic shapes. Methods: An automated edge detection algorithm was used to catalogue the breast shapes of clinically acquired cranio-caudal (CC) and medio-lateral oblique (MLO) view mammograms from a large database of digital mammography images. Principal component analysis (PCA) was performed on these shapes to reduce the information contained within the shapes to a small number of linearly independent variables. The breast shape models, one of each view, were developed from the identified principal components, and their ability to reproduce the shape of breasts from an independent set of mammograms not used in the PCA, was assessed both visually and quantitatively by calculating the average distance error (ADE). Results: The PCA breast shape models of the CC and MLO mammographic views based on six principal components, in which 99.2% and 98.0%, respectively, of the total variance of the dataset is contained, were found to be able to reproduce breast shapes with strong fidelity (CC view mean ADE = 0.90 mm, MLO view mean ADE = 1.43 mm) and to generate new clinically realistic shapes. The PCA models based on fewer principal components were also successful, but to a lesser degree, as the two-component model exhibited a mean ADE = 2.99 mm for the CC view, and a mean ADE = 4.63 mm for the MLO view. The four-component models exhibited a mean ADE = 1.47 mm for the CC view and a mean ADE = 2.14 mm for the MLO view. Paired t-tests of the ADE values of each image between models showed that these differences were statistically significant (max p-value = 0.0247). Visual examination of modeled breast shapes confirmed these results. Histograms of the PCA parameters associated with the six principal components were fitted with Gaussian distributions. The six

  18. Objective models of compressed breast shapes undergoing mammography

    International Nuclear Information System (INIS)

    Feng, Steve Si Jia; Patel, Bhavika; Sechopoulos, Ioannis

    2013-01-01

    Purpose: To develop models of compressed breasts undergoing mammography based on objective analysis, that are capable of accurately representing breast shapes in acquired clinical images and generating new, clinically realistic shapes. Methods: An automated edge detection algorithm was used to catalogue the breast shapes of clinically acquired cranio-caudal (CC) and medio-lateral oblique (MLO) view mammograms from a large database of digital mammography images. Principal component analysis (PCA) was performed on these shapes to reduce the information contained within the shapes to a small number of linearly independent variables. The breast shape models, one of each view, were developed from the identified principal components, and their ability to reproduce the shape of breasts from an independent set of mammograms not used in the PCA, was assessed both visually and quantitatively by calculating the average distance error (ADE). Results: The PCA breast shape models of the CC and MLO mammographic views based on six principal components, in which 99.2% and 98.0%, respectively, of the total variance of the dataset is contained, were found to be able to reproduce breast shapes with strong fidelity (CC view mean ADE = 0.90 mm, MLO view mean ADE = 1.43 mm) and to generate new clinically realistic shapes. The PCA models based on fewer principal components were also successful, but to a lesser degree, as the two-component model exhibited a mean ADE = 2.99 mm for the CC view, and a mean ADE = 4.63 mm for the MLO view. The four-component models exhibited a mean ADE = 1.47 mm for the CC view and a mean ADE = 2.14 mm for the MLO view. Paired t-tests of the ADE values of each image between models showed that these differences were statistically significant (max p-value = 0.0247). Visual examination of modeled breast shapes confirmed these results. Histograms of the PCA parameters associated with the six principal components were fitted with Gaussian distributions. The six

  19. Confidence of model based shape reconstruction from sparse data

    DEFF Research Database (Denmark)

    Baka, N.; de Bruijne, Marleen; Reiber, J. H. C.

    2010-01-01

    Statistical shape models (SSM) are commonly applied for plausible interpolation of missing data in medical imaging. However, when fitting a shape model to sparse information, many solutions may fit the available data. In this paper we derive a constrained SSM to fit noisy sparse input landmarks...

  20. Modeling self-occlusions in dynamic shape and appearance tracking

    KAUST Repository

    Yang, Yanchao

    2013-12-01

    We present a method to track the precise shape of a dynamic object in video. Joint dynamic shape and appearance models, in which a template of the object is propagated to match the object shape and radiance in the next frame, are advantageous over methods employing global image statistics in cases of complex object radiance and cluttered background. In cases of complex 3D object motion and relative viewpoint change, self-occlusions and disocclusions of the object are prominent, and current methods employing joint shape and appearance models are unable to accurately adapt to new shape and appearance information, leading to inaccurate shape detection. In this work, we model self-occlusions and dis-occlusions in a joint shape and appearance tracking framework. Experiments on video exhibiting occlusion/dis-occlusion, complex radiance and background show that occlusion/dis-occlusion modeling leads to superior shape accuracy compared to recent methods employing joint shape/appearance models or employing global statistics. © 2013 IEEE.

  1. Modeling Self-Occlusions/Disocclusions in Dynamic Shape and Appearance Tracking for Obtaining Precise Shape

    KAUST Repository

    Yang, Yanchao

    2013-05-01

    We present a method to determine the precise shape of a dynamic object from video. This problem is fundamental to computer vision, and has a number of applications, for example, 3D video/cinema post-production, activity recognition and augmented reality. Current tracking algorithms that determine precise shape can be roughly divided into two categories: 1) Global statistics partitioning methods, where the shape of the object is determined by discriminating global image statistics, and 2) Joint shape and appearance matching methods, where a template of the object from the previous frame is matched to the next image. The former is limited in cases of complex object appearance and cluttered background, where global statistics cannot distinguish between the object and background. The latter is able to cope with complex appearance and a cluttered background, but is limited in cases of camera viewpoint change and object articulation, which induce self-occlusions and self-disocclusions of the object of interest. The purpose of this thesis is to model self-occlusion/disocclusion phenomena in a joint shape and appearance tracking framework. We derive a non-linear dynamic model of the object shape and appearance taking into account occlusion phenomena, which is then used to infer self-occlusions/disocclusions, shape and appearance of the object in a variational optimization framework. To ensure robustness to other unmodeled phenomena that are present in real-video sequences, the Kalman filter is used for appearance updating. Experiments show that our method, which incorporates the modeling of self-occlusion/disocclusion, increases the accuracy of shape estimation in situations of viewpoint change and articulation, and out-performs current state-of-the-art methods for shape tracking.

  2. Shell model calculations at superdeformed shapes

    International Nuclear Information System (INIS)

    Nazarewicz, W.; Dobaczewski, J.; Van Isacker, P.

    1991-01-01

    Spectroscopy of superdeformed nuclear states opens up an exciting possibility to probe new properties of the nuclear mean field. In particular, the unusually deformed atomic nucleus can serve as a microscopic laboratory of quantum-mechanical symmetries of a three dimensional harmonic oscillator. The classifications and coupling schemes characteristic of weakly deformed systems are expected to be modified in the superdeformed world. The ''superdeformed'' symmetries lead to new quantum numbers and new effective interactions that can be employed in microscopic calculations. New classification schemes can be directly related to certain geometrical properties of the nuclear shape. 63 refs., 7 figs

  3. General quadrupole shapes in the Interacting Boson Model

    International Nuclear Information System (INIS)

    Leviatan, A.

    1990-01-01

    Characteristic attributes of nuclear quadrupole shapes are investigated within the algebraic framework of the Interacting Boson Model. For each shape the Hamiltonian is resolved into intrinsic and collective parts, normal modes are identified and intrinsic states are constructed and used to estimate transition matrix elements. Special emphasis is paid to new features (e.g. rigid triaxiality and coexisting deformed shapes) that emerge in the presence of the three-body interactions. 27 refs

  4. Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed structural panels in bending

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2017-01-01

    This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model...

  5. Rapid de novo shape encoding: a challenge to connectionist modeling

    OpenAIRE

    Greene, Ernest

    2018-01-01

    Neural network (connectionist) models are designed to encode image features and provide the building blocks for object and shape recognition. These models generally call for: a) initial diffuse connections from one neuron population to another, and b) training to bring about a functional change in those connections so that one or more high-tier neurons will selectively respond to a specific shape stimulus. Advanced models provide for translation, size, and rotation invariance. The present dis...

  6. Statistical shape model with random walks for inner ear segmentation

    DEFF Research Database (Denmark)

    Pujadas, Esmeralda Ruiz; Kjer, Hans Martin; Piella, Gemma

    2016-01-01

    is required. We propose a new framework for segmentation of micro-CT cochlear images using random walks combined with a statistical shape model (SSM). The SSM allows us to constrain the less contrasted areas and ensures valid inner ear shape outputs. Additionally, a topology preservation method is proposed...

  7. Nineth Rib Syndrome after 10th Rib Resection

    OpenAIRE

    Yu, Hyun Jeong; Jeong, Yu Sub; Lee, Dong Hoon; Yim, Kyoung Hoon

    2016-01-01

    The 12th rib syndrome is a disease that causes pain between the upper abdomen and the lower chest. It is assumed that the impinging on the nerves between the ribs causes pain in the lower chest, upper abdomen, and flank. A 74-year-old female patient visited a pain clinic complaining of pain in her back, and left chest wall at a 7 on the 0-10 Numeric Rating scale (NRS). She had a lateral fixation at T12-L2, 6 years earlier. After the operation, she had multiple osteoporotic compression fractur...

  8. Development and validation of a human biomechanical model for rib fracture and thorax injuries in blunt impact.

    Science.gov (United States)

    Cai, Zhihua; Lan, Fengchong; Chen, Jiqing

    2015-07-01

    From 1990 to approximately 50,000-120,000 people die annually of road traffic accidents in China. Traffic accidents are the main cause of death of Chinese adults aged 15-45 years. This study aimed to determine the biomechanical response and injury tolerance of the human body in traffic accidents. The subject was a 35-year-old male with a height of 170 cm, weight of 70 kg and Chinese characteristics at the 50th percentile. Geometry was generated by computed tomography and magnetic resonance imaging. A human-body biomechanical model was then developed. The model featured in great detail the main anatomical characteristics of skeletal tissues, soft tissues and internal organs, including the head, neck, shoulder, thoracic cage, abdomen, spine, pelvis, pleurae and lungs, heart, aorta, arms, legs, and other muscle tissues and skeletons. The material properties of all tissues in the human body model were obtained from the literature. Material properties were developed in the LS-DYNA code to simulate the mechanical behaviour of the biological tissues in the human body. The model was validated against cadaver responses to frontal and side impact. The predicted model response reasonably agreed with the experimental data, and the model can further be used to evaluate thoracic injury in real-world crashes. We believe that the transportation industry can use numerical models in the future to simultaneously reduce physical testing and improve automotive safety.

  9. Modeling the variability of shapes of a human placenta.

    Science.gov (United States)

    Yampolsky, M; Salafia, C M; Shlakhter, O; Haas, D; Eucker, B; Thorp, J

    2008-09-01

    Placentas are generally round/oval in shape, but "irregular" shapes are common. In the Collaborative Perinatal Project data, irregular shapes were associated with lower birth weight for placental weight, suggesting variably shaped placentas have altered function. (I) Using a 3D one-parameter model of placental vascular growth based on Diffusion Limited Aggregation (an accepted model for generating highly branched fractals), models were run with a branching density growth parameter either fixed or perturbed at either 5-7% or 50% of model growth. (II) In a data set with detailed measures of 1207 placental perimeters, radial standard deviations of placental shapes were calculated from the umbilical cord insertion, and from the centroid of the shape (a biologically arbitrary point). These two were compared to the difference between the observed scaling exponent and the Kleiber scaling exponent (0.75), considered optimal for vascular fractal transport systems. Spearman's rank correlation considered pcentroid) was associated with differences from the Kleiber exponent (p=0.006). A dynamical DLA model recapitulates multilobate and "star" placental shapes via changing fractal branching density. We suggest that (1) irregular placental outlines reflect deformation of the underlying placental fractal vascular network, (2) such irregularities in placental outline indicate sub-optimal branching structure of the vascular tree, and (3) this accounts for the lower birth weight observed in non-round/oval placentas in the Collaborative Perinatal Project.

  10. Epidural Analgesia after Rib Fractures.

    Science.gov (United States)

    Zaw, Andrea A; Murry, Jason; Hoang, David; Chen, Kevin; Louy, Charles; Bloom, Matthew B; Melo, Nicolas; Alban, Rodrigo F; Margulies, Daniel R; Ley, Eric J

    2015-10-01

    Pain associated with rib fractures impairs respiratory function and increases pulmonary morbidity. The purpose of this study was to determine how epidural catheters alter mortality and complications in trauma patients. We performed a retrospective study involving adult blunt trauma patients with moderate-to-severe injuries from January 1, 2004 to December 31, 2013. During the 10-year period, 526 patients met the inclusion criteria; 43/526 (8%) patients had a catheter placed. Mean age of patients with epidural catheter (CATH) was higher compared with patients without epidural catheter (NOCATH) (54 vs 48 years, P = 0.021), Injury Severity Score was similar (26 CATH vs 27 NOCATH, P = 0.84), and CATH had higher mean rib fractures (7.4 vs 4.1, P ribs fractured. The epidural cohort had longer hospital LOS and decreased mortality. In contrast to other studies, DVT rates were increased in patients who received epidural catheters.

  11. Search for the maximum efficiency of a ribbed-surfaces device, providing a tight seal

    International Nuclear Information System (INIS)

    Boutin, Jeanne.

    1977-04-01

    The purpose of this experiment was to determine the geometrical characteristics of ribbed surfaces used to equip devices in translation or slow rotation motion and having to form an acceptable seal between slightly viscous fluids. It systematically studies the pressure loss coefficient lambda in function of the different parameters setting the form of ribs and their relative position on the opposite sides. It shows that the passages with two ribbed surfaces lead to highly better results than those with only one, the maximum value of lambda, equal to 0.5, being obtained with the ratios: pitch/clearance = 5, depth of groove/clearance = 1,2, and with their teeth face to face on the two opposite ribbed surfaces. With certain shapes, alternate position of ribs can lead to the maximum of lambda yet lower than 0.5 [fr

  12. Tensegrity Models and Shape Control of Vehicle Formations

    OpenAIRE

    Nabet, Benjamin; Leonard, Naomi Ehrich

    2009-01-01

    Using dynamic models of tensegrity structures, we derive provable, distributed control laws for stabilizing and changing the shape of a formation of vehicles in the plane. Tensegrity models define the desired, controlled, multi-vehicle system dynamics, where each node in the tensegrity structure maps to a vehicle and each interconnecting strut or cable in the structure maps to a virtual interconnection between vehicles. Our method provides a smooth map from any desired planar formation shape ...

  13. Modelling the wedge shape for the virtual wedge

    International Nuclear Information System (INIS)

    Chang Liyun; Ho Shengyow; Chen, Helen H W

    2003-01-01

    We present a method to model the virtual wedge shape in a 3D treatment planning system as a physical wedge. The virtual wedge shape was determined using the measured dose profile of the virtual wedge at a chosen reference depth. The differences between the calculated and the measured dose profiles for the virtual wedge were within 0.5% at the reference depth, and within 2.5% at other depths. This method provides a fast and accurate way to implement the virtual wedge into our planning system for any wedge angles. This method is also applicable to model the physical wedge shapes with comparable good results

  14. X-ray diagnosis of rib chondrosarcoma

    International Nuclear Information System (INIS)

    Smakova, M.S.

    1982-01-01

    A study was made on X-ray images of 24 patients, suffering from rib chondrosarcoma with relapses. X-ray symptoms of rib chondrosarcoma, depending on process localization were improved. Chondrosarcoma of rib cartilage is characterized by soft-tissue component with calcareous inclusions or without them. Chondrosarcoma of rib bone is characterized by destruction and soft-tissue component. Chondrosarcoma relapses were localized in soft tissues

  15. Isolated rib fractures in geriatric patients

    OpenAIRE

    Elmistekawy, Elsayed M.; Hammad, Abd Almohsen M.

    2007-01-01

    Introduction: The goal of this study was to investigate the short-term outcomes in patients older than 60 years with isolated rib fractures and admitted to emergency hospital. Materials and Methods: This study included patients who were 60 years old or more and sustained blunt chest injury and had isolated rib fractures. The following data were obtained from the medical records: age, gender, number of fracture ribs, side of fracture ribs, mechanism and nature of injury, preexisting medical...

  16. Bolted Ribs Analysis for the ITER Vacuum Vessel using Finite Element Submodelling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zarzalejos, José María, E-mail: jose.zarzalejos@ext.f4e.europa.eu [External at F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Fernández, Elena; Caixas, Joan; Bayón, Angel [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Polo, Joaquín [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Guirao, Julio [Numerical Analysis Technologies, S L., Marqués de San Esteban 52, Entlo, 33209 Gijon (Spain); García Cid, Javier [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Rodríguez, Eduardo [Mechanical Engineering Department EPSIG, University of Oviedo, Gijon (Spain)

    2014-10-15

    Highlights: • The ITER Vacuum Vessel Bolted Ribs assemblies are modelled using Finite Elements. • Finite Element submodelling techniques are used. • Stress results are obtained for all the assemblies and a post-processing is performed. • All the elements of the assemblies are compliant with the regulatory provisions. • Submodelling is a time-efficient solution to verify the structural integrity of this type of structures. - Abstract: The ITER Vacuum Vessel (VV) primary function is to enclose the plasmas produced by the ITER Tokamak. Since it acts as the first radiological barrier of the plasma, it is classified as a class 2 welded box structure, according to RCC-MR 2007. The VV is made of an inner and an outer D-shape, 60 mm-thick double shell connected through thick massive bars (housings) and toroidal and poloidal structural stiffening ribs. In order to provide neutronic shielding to the ex-vessel components, the space between shells is filled with borated steel plates, called In-Wall Shielding (IWS) blocks, and water. In general, these blocks are connected to the IWS ribs which are connected to adjacent housings. The development of a Finite Element model of the ITER VV including all its components in detail is unaffordable from the computational point of view due to the large number of degrees of freedom it would require. This limitation can be overcome by using submodelling techniques to simulate the behaviour of the bolted ribs assemblies. Submodelling is a Finite Element technique which allows getting more accurate results in a given region of a coarse model by generating an independent, finer model of the region under study. In this paper, the methodology and several simulations of the VV bolted ribs assemblies using submodelling techniques are presented. A stress assessment has been performed for the elements involved in the assembly considering possible types of failure and including stress classification and categorization techniques to analyse

  17. Shape determinative slice localization for patient-specific masseter modeling using shape-based interpolation

    Energy Technology Data Exchange (ETDEWEB)

    Ng, H.P. [NUS Graduate School for Integrative Sciences and Engineering (Singapore); Biomedical Imaging Lab., Agency for Science Technology and Research (Singapore); Foong, K.W.C. [NUS Graduate School for Integrative Sciences and Engineering (Singapore); Dept. of Preventive Dentistry, National Univ. of Singapore (Singapore); Ong, S.H. [Dept. of Electrical and Computer Engineering, National Univ. of Singapore (Singapore); Div. of Bioengineering, National Univ. of Singapore (Singapore); Liu, J.; Nowinski, W.L. [Biomedical Imaging Lab., Agency for Science Technology and Research (Singapore); Goh, P.S. [Dept. of Diagnostic Radiology, National Univ. of Singapore (Singapore)

    2007-06-15

    The masseter plays a critical role in the mastication system. A hybrid method to shape-based interpolation is used to build the masseter model from magnetic resonance (MR) data sets. The main contribution here is the localizing of determinative slices in the data sets where clinicians are required to perform manual segmentations in order for an accurate model to be built. Shape-based criteria were used to locate the candidates for determinative slices and fuzzy-c-means (FCM) clustering technique was used to establish the determinative slices. Five masseter models were built in our work and the average overlap indices ({kappa}) achieved is 85.2%. This indicates that there is good agreement between the models and the manual contour tracings. In addition, the time taken, as compared to manually segmenting all the slices, is significantly lesser. (orig.)

  18. Shape determinative slice localization for patient-specific masseter modeling using shape-based interpolation

    International Nuclear Information System (INIS)

    Ng, H.P.; Foong, K.W.C.; Ong, S.H.; Liu, J.; Nowinski, W.L.; Goh, P.S.

    2007-01-01

    The masseter plays a critical role in the mastication system. A hybrid method to shape-based interpolation is used to build the masseter model from magnetic resonance (MR) data sets. The main contribution here is the localizing of determinative slices in the data sets where clinicians are required to perform manual segmentations in order for an accurate model to be built. Shape-based criteria were used to locate the candidates for determinative slices and fuzzy-c-means (FCM) clustering technique was used to establish the determinative slices. Five masseter models were built in our work and the average overlap indices (κ) achieved is 85.2%. This indicates that there is good agreement between the models and the manual contour tracings. In addition, the time taken, as compared to manually segmenting all the slices, is significantly lesser. (orig.)

  19. Evaluation of Solar Air Heater Performance with Artificial Rib Roughness over the Absorber Plate using Finite Element Modelling Analysis

    Science.gov (United States)

    Kumar, K. Ravi; Nikhil Varma, P.; Jagadeesh, N.; Sandeep, J. V.; Cheepu, Muralimohan; Venkateswarlu, D.; Srinivas, B.

    2018-03-01

    Among the different renewable energy resources, solar energy is widely used due to its quantitative intensity factor. Solar air heater is cheap, simple in design and has got wide range of applications. A modest solar air heater has a lower in heat transfer and thermal performance as it has heat transfer coefficient lower in between coated absorber plate and the carrier fluid. This low thermal performance can be reduced to a greater extent by introducing the artificially created roughness over the absorber plate of the solar heater. In the present study, the combination of various geometries and roughness’s on the absorber plate are reported. Methods have been developed and implemented in order to improve the rate of the heat transfer. A comparison is drawn among different geometries to select the most effective absorber plate roughness. For flow analysis k-ω SST model was used and the constant heat flux was taken as 1100 W/m2. The Reynolds number is varied in a range from 3000 to 20000. The variation of different parameters temperature, Nusselt number, turbulence kinetic energy and heat transfer coefficient with Reynolds number were examined and discussed.

  20. Flow field analysis inside a gas turbine trailing edge cooling channel under static and rotating conditions: Effect of ribs

    International Nuclear Information System (INIS)

    Mucignat, C.; Armellini, A.; Casarsa, L.

    2013-01-01

    Highlights: • Detailed PIV and Stereo PIV investigation on a rotating test section. • Static channel: absence of guiding effect for inclined ribs. • Static channel: the ribs influence significantly the flow also at the trailing edge. • Rotating channel: opposite flow features with respect to the static case. • The analyzed flow features justify the previously observed thermal performances. -- Abstract: The present work is part of a wider research program which concerns the aero-thermal characterization of cooling channels for the trailing edge of gas turbine blades. The selected passage model is characterized by a trapezoidal cross-section of high aspect-ratio and coolant discharge at the blade tip and along the wedge-shaped trailing edge, where seven elongated pedestals are also installed. In this contribution, a new channel configuration provided with inclined ribs installed inside the radial development region is analyzed, extending the previous results and completing the already available data base, thus providing an overall review of the aero-thermal performance of the considered passage. The velocity field inside the channel was measured by means of 2D and Stereo-PIV techniques in multiple flow planes under static and rotating conditions. The tests were performed under engine similar conditions with respect to both Reynolds (Re = 20,000) and Rotation (Ro = 0, 0.23) numbers. Time averaged flow fields and velocity fluctuation data inside the stationary and rotating channels are analyzed and also critically compared with the data acquired without ribs. In this way the effects on the flow field induced by both rotation and ribs are clearly described. In particular, the ribs modify substantially both the flow field on the channel walls where they are installed and the 3D separation structures that surround the pedestals. If also rotation is taken into account, the relative flow field is characterized by a considerable guiding effect of the ribs coupled

  1. Modelling the shape hierarchy for visually guided grasping

    Directory of Open Access Journals (Sweden)

    Omid eRezai

    2014-10-01

    Full Text Available The monkey anterior intraparietal area (AIP encodes visual information about three-dimensional object shape that is used to shape the hand for grasping. We modelled shape tuning in visual AIP neurons and its relationship with curvature and gradient information from the caudal intraparietal area (CIP. The main goal was to gain insight into the kinds of shape parameterizations that can account for AIP tuning and that are consistent with both the inputs to AIP and the role of AIP in grasping. We first experimented with superquadric shape parameters. We considered superquadrics because they occupy a role in robotics that is similar to AIP, in that superquadric fits are derived from visual input and used for grasp planning. We also experimented with an alternative shape parameterization that was based on an Isomap dimension reduction of spatial derivatives of depth (i.e. distance from the observer to the object surface. We considered an Isomap-based model because its parameters lacked discontinuities between similar shapes. When we matched the dimension of the Isomap to the number of superquadric parameters, the superquadric model fit the AIP data somewhat more closely. However, higher-dimensional Isomaps provided excellent fits. Also, we found that the Isomap parameters could be approximated much more accurately than superquadric parameters by feedforward neural networks with CIP-like inputs. We conclude that Isomaps, or perhaps alternative dimension reductions of visual inputs to AIP, provide a promising model of AIP electrophysiology data. However (in contrast with superquadrics further work is needed to test whether such shape parameterizations actually provide an effective basis for grasp control.

  2. Modeling and Simulation of Turbulent Flows through a Solar Air Heater Having Square-Sectioned Transverse Rib Roughness on the Absorber Plate

    Directory of Open Access Journals (Sweden)

    Anil Singh Yadav

    2013-01-01

    Full Text Available Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P and rib-height (e have been taken such that the relative roughness pitch (P/e=14.29 remains constant. The relative roughness height, e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

  3. Modeling and simulation of turbulent flows through a solar air heater having square-sectioned transverse rib roughness on the absorber plate.

    Science.gov (United States)

    Yadav, Anil Singh; Bhagoria, J L

    2013-01-01

    Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P) and rib-height (e) have been taken such that the relative roughness pitch (P/e = 14.29) remains constant. The relative roughness height, e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

  4. Ideal Coulomb Plasma Approximation in Line Shape Models: Problematic Issues

    Directory of Open Access Journals (Sweden)

    Joel Rosato

    2014-06-01

    Full Text Available In weakly coupled plasmas, it is common to describe the microfield using a Debye model. We examine here an “artificial” ideal one-component plasma with an infinite Debye length, which has been used for the test of line shape codes. We show that the infinite Debye length assumption can lead to a misinterpretation of numerical simulations results, in particular regarding the convergence of calculations. Our discussion is done within an analytical collision operator model developed for hydrogen line shapes in near-impact regimes. When properly employed, this model can serve as a reference for testing the convergence of simulations.

  5. Shape Modeling of a Concentric-tube Continuum Robot

    DEFF Research Database (Denmark)

    Bai, Shaoping; Xing, Charles Chuhao

    2012-01-01

    Concentric-tube continuum robots feature with simple and compact structures and have a great potential in medical applications. The paper is concerned with the shape modeling of a type of concentric-tube continuum robot built with a collection of super-elastic NiTiNol tubes. The mechanics...... is modeled on the basis of energy approach for both the in-plane and out-plane cases. The torsional influences on the shape of the concentric-tube robots are considered. An experimental device was build for the model validation. The results of simulation and experiments are included and analyzed....

  6. Shape Modelling Using Markov Random Field Restoration of Point Correspondences

    DEFF Research Database (Denmark)

    Paulsen, Rasmus Reinhold; Hilger, Klaus Baggesen

    2003-01-01

    A method for building statistical point distribution models is proposed. The novelty in this paper is the adaption of Markov random field regularization of the correspondence field over the set of shapes. The new approach leads to a generative model that produces highly homogeneous polygonized sh...

  7. Gallbladder shape extraction from ultrasound images using active contour models.

    Science.gov (United States)

    Ciecholewski, Marcin; Chochołowicz, Jakub

    2013-12-01

    Gallbladder function is routinely assessed using ultrasonographic (USG) examinations. In clinical practice, doctors very often analyse the gallbladder shape when diagnosing selected disorders, e.g. if there are turns or folds of the gallbladder, so extracting its shape from USG images using supporting software can simplify a diagnosis that is often difficult to make. The paper describes two active contour models: the edge-based model and the region-based model making use of a morphological approach, both designed for extracting the gallbladder shape from USG images. The active contour models were applied to USG images without lesions and to those showing specific disease units, namely, anatomical changes like folds and turns of the gallbladder as well as polyps and gallstones. This paper also presents modifications of the edge-based model, such as the method for removing self-crossings and loops or the method of dampening the inflation force which moves nodes if they approach the edge being determined. The user is also able to add a fragment of the approximated edge beyond which neither active contour model will move if this edge is incomplete in the USG image. The modifications of the edge-based model presented here allow more precise results to be obtained when extracting the shape of the gallbladder from USG images than if the morphological model is used. © 2013 Elsevier Ltd. Published by Elsevier Ltd. All rights reserved.

  8. Rib Fracture Diagnosis in the Panscan Era.

    Science.gov (United States)

    Murphy, Charles E; Raja, Ali S; Baumann, Brigitte M; Medak, Anthony J; Langdorf, Mark I; Nishijima, Daniel K; Hendey, Gregory W; Mower, William R; Rodriguez, Robert M

    2017-12-01

    With increased use of chest computed tomography (CT) in trauma evaluation, traditional teachings in regard to rib fracture morbidity and mortality may no longer be accurate. We seek to determine rates of rib fracture observed on chest CT only; admission and mortality of patients with isolated rib fractures, rib fractures observed on CT only, and first or second rib fractures; and first or second rib fracture-associated great vessel injury. We conducted a planned secondary analysis of 2 prospectively enrolled cohorts of the National Emergency X-Radiography Utilization Study chest studies, which evaluated patients with blunt trauma who were older than 14 years and received chest imaging in the emergency department. We defined rib fractures and other thoracic injuries according to CT reports and followed patients through their hospital course to determine outcomes. Of 8,661 patients who had both chest radiograph and chest CT, 2,071 (23.9%) had rib fractures, and rib fractures were observed on chest CT only in 1,368 cases (66.1%). Rib fracture patients had higher admission rates (88.7% versus 45.8%; mean difference 42.9%; 95% confidence interval [CI] 41.4% to 44.4%) and mortality (5.6% versus 2.7%; mean difference 2.9%; 95% CI 1.8% to 4.0%) than patients without rib fracture. The mortality of patients with rib fracture observed on chest CT only was not statistically significantly different from that of patients with fractures also observed on chest radiograph (4.8% versus 5.7%; mean difference -0.9%; 95% CI -3.1% to 1.1%). Patients with first or second rib fractures had significantly higher mortality (7.4% versus 4.1%; mean difference 3.3%; 95% CI 0.2% to 7.1%) and prevalence of concomitant great vessel injury (2.8% versus 0.6%; mean difference 2.2%; 95% CI 0.6% to 4.9%) than patients with fractures of ribs 3 to 12, and the odds ratio of great vessel injury with first or second rib fracture was 4.4 (95% CI 1.8 to 10.4). Under trauma imaging protocols that commonly

  9. Low Complexity Models to improve Incomplete Sensitivities for Shape Optimization

    Science.gov (United States)

    Stanciu, Mugurel; Mohammadi, Bijan; Moreau, Stéphane

    2003-01-01

    The present global platform for simulation and design of multi-model configurations treat shape optimization problems in aerodynamics. Flow solvers are coupled with optimization algorithms based on CAD-free and CAD-connected frameworks. Newton methods together with incomplete expressions of gradients are used. Such incomplete sensitivities are improved using reduced models based on physical assumptions. The validity and the application of this approach in real-life problems are presented. The numerical examples concern shape optimization for an airfoil, a business jet and a car engine cooling axial fan.

  10. Photometry and shape modeling of Mars crosser asteroid (1011 Laodamia

    Directory of Open Access Journals (Sweden)

    Apostolovska G.

    2014-01-01

    Full Text Available An analysis of photometric observations of Mars crosser asteroid 1011 Laodamia conducted at Bulgarian National Astronomical Observatory Rozhen over a twelve year interval (2002, 2003, 2004, 2006, 2007, 2008, 2011, 2012 and 2013 is made. Based on the obtained lightcurves the spin vector, sense of rotation, and preliminary shape model of (1011 Laodamia have been determined using the lightcurve inversion method. The aim of this investigation is to increase the set of asteroids with known spin and shape parameters and to contribute in improving the model in combination with other techniques and sparse data produced by photometric asteroid surveys such as Pan-STARRS or GAIA.

  11. Detecting hippocampal shape changes in Alzheimer's disease using statistical shape models

    Science.gov (United States)

    Shen, Kaikai; Bourgeat, Pierrick; Fripp, Jurgen; Meriaudeau, Fabrice; Salvado, Olivier

    2011-03-01

    The hippocampus is affected at an early stage in the development of Alzheimer's disease (AD). Using brain Magnetic Resonance (MR) images, we can investigate the effect of AD on the morphology of the hippocampus. Statistical shape models (SSM) are usually used to describe and model the hippocampal shape variations among the population. We use the shape variation from SSM as features to classify AD from normal control cases (NC). Conventional SSM uses principal component analysis (PCA) to compute the modes of variations among the population. Although these modes are representative of variations within the training data, they are not necessarily discriminant on labelled data. In this study, a Hotelling's T 2 test is used to qualify the landmarks which can be used for PCA. The resulting variation modes are used as predictors of AD from NC. The discrimination ability of these predictors is evaluated in terms of their classification performances using support vector machines (SVM). Using only landmarks statistically discriminant between AD and NC in SSM showed a better separation between AD and NC. These predictors also showed better correlation to the cognitive scores such as mini-mental state examination (MMSE) and Alzheimer's disease assessment scale (ADAS).

  12. [Internal fixation treatment of multiple rib fractures with absorbable rib-connecting-pins under epidural anesthesia].

    Science.gov (United States)

    Liu, Jinliang; Li, Keyao; Ju, Zhenlong; Bai, Yan

    2011-03-01

    To study the indications, methods and experience of absorbable rib-connecting-pins fixation in the treatment of multiple rib fractures. 52 cases with multiple rib fractures were performed internal fixation with absorbable rib-connecting-pins under epidural anesthesia. All cases were followed up for 1 to 12 months, with an average of 5 months. All fractures were achieved healing in 3 to 6 months after the operation and were not found chest wall deformity. Absorbable rib-connecting-pins fixation is a simple and effective method and worthies recommending to perform operation for the appropriate cases with multiple rib fractures.

  13. Golfer's fracture of the ribs

    International Nuclear Information System (INIS)

    Lim, J. H.

    1980-01-01

    Golfer's fracture is stress fracture of the posterior portion of left 3, 4, 5, 6 or 7th ribs of golfer's, usually beginners,and it is considered due to exposure to unaccustomed severe exercise of this fascinating sport. Healing is usually uneventful, but possible complication may occur, because symptom is mild and golfers continue the exercise with physical therapy such as massage. Author report 4 cases of golfer's fracture, including 1 case complicated by platelike at electasis of lung.

  14. Golfer's fracture of the ribs

    Energy Technology Data Exchange (ETDEWEB)

    Lim, J H [Seoul District Armed Forces General Hospital, Seoul (Korea, Republic of)

    1980-06-15

    Golfer's fracture is stress fracture of the posterior portion of left 3, 4, 5, 6 or 7th ribs of golfer's, usually beginners,and it is considered due to exposure to unaccustomed severe exercise of this fascinating sport. Healing is usually uneventful, but possible complication may occur, because symptom is mild and golfers continue the exercise with physical therapy such as massage. Author report 4 cases of golfer's fracture, including 1 case complicated by platelike at electasis of lung.

  15. Rib forming tool for tubing

    Science.gov (United States)

    Rowley, James P.; Lewandowski, Edward F.; Groh, Edward F.

    1976-01-01

    Three cylindrical rollers are rotatably mounted equidistant from the center of a hollow tool head on radii spaced 120.degree. apart. Each roller has a thin flange; the three flanges lie in a single plane to form an internal circumferential rib in a rotating tubular workpiece. The tool head has two complementary parts with two rollers in one part of the head and one roller in the other part; the two parts are joined by a hinge. A second hinge, located so the rollers are between the two hinges, connects one of the parts to a tool bar mounted in a lathe tool holder. The axes of rotation of both hinges and all three rollers are parallel. A hole exposing equal portions of the three roller flanges is located in the center of the tool head. The two hinges permit the tool head to be opened and rotated slightly downward, taking the roller flanges out of the path of the workpiece which is supported on both ends and rotated by the lathe. The parts of the tool head are then closed on the workpiece so that the flanges are applied to the workpiece and form the rib. The tool is then relocated for forming of the next rib.

  16. Segmentation of ribs in digital chest radiographs

    Science.gov (United States)

    Cong, Lin; Guo, Wei; Li, Qiang

    2016-03-01

    Ribs and clavicles in posterior-anterior (PA) digital chest radiographs often overlap with lung abnormalities such as nodules, and cause missing of these abnormalities, it is therefore necessary to remove or reduce the ribs in chest radiographs. The purpose of this study was to develop a fully automated algorithm to segment ribs within lung area in digital radiography (DR) for removal of the ribs. The rib segmentation algorithm consists of three steps. Firstly, a radiograph was pre-processed for contrast adjustment and noise removal; second, generalized Hough transform was employed to localize the lower boundary of the ribs. In the third step, a novel bilateral dynamic programming algorithm was used to accurately segment the upper and lower boundaries of ribs simultaneously. The width of the ribs and the smoothness of the rib boundaries were incorporated in the cost function of the bilateral dynamic programming for obtaining consistent results for the upper and lower boundaries. Our database consisted of 93 DR images, including, respectively, 23 and 70 images acquired with a DR system from Shanghai United-Imaging Healthcare Co. and from GE Healthcare Co. The rib localization algorithm achieved a sensitivity of 98.2% with 0.1 false positives per image. The accuracy of the detected ribs was further evaluated subjectively in 3 levels: "1", good; "2", acceptable; "3", poor. The percentages of good, acceptable, and poor segmentation results were 91.1%, 7.2%, and 1.7%, respectively. Our algorithm can obtain good segmentation results for ribs in chest radiography and would be useful for rib reduction in our future study.

  17. Anatomical variation of human thoracic rib in dry bone.

    Directory of Open Access Journals (Sweden)

    Dr. Nalini Konkani

    2017-12-01

    Full Text Available Introduction: The Ribs are essential structure of osseous thorax and provide information that aids in the interpretation of radiologic images. The purpose of this study to investigate variations in thoracic rib and its morphological & clinical importance. So, In present study attempted to find out additional intercostal spaces due to bifurcation of ribs, less intercostal space due to fusion of ribs, variation of the normal ribs like, gap in the rib, fusion of one rib to another at a shaft of rib. Congenital abnormalities of the ribs are usually asymptomatic, often discovered incidentally on chest X-ray. Effects of this neuroskeletal anomaly can include respiratory difficulties and neurological limitations.Material & Method: The study was carried out in Bone Store of Department of Anatomy, B. J. Medical College, Ahmedabad, Gujarat. Study was carried out on 500 human dried ribs. And the variations in the ribs are studied. We got variation in the human ribs and studied. Result : Variations were seen like out of 500 ribs, Bifid rib having two ends 9(1.8%, rib having bifid space 2(0.4%, fusion rib at the level of shaft 1(0.2%, fusion of first rib and second rib 1(0.2%,first rib having two ends 1(0.2%. Conclusion: Bifid rib is an anatomical variant where the sternal end of the rib is cleaved into two. So we can rule out mesodermal abnormalities, parenchymal lung disease, chest wall tumor or costal fracture.

  18. Thermomechanical model for NiTi shape memory wires

    International Nuclear Information System (INIS)

    Frost, M; Sedlák, P; Sippola, M; Šittner, P

    2010-01-01

    A simple one-dimensional rate-independent model is proposed. It is able to capture responses of a NiTi shape memory alloy wire element to mechanical and thermal loadings. Since the model takes into account martensitic phase transformation as well as deformation processes in the martensite, both shape memory effects and pseudoelasticity can be simulated. The model introduces non-hysteretic transformation strain. Particular attention was paid to description of partial loading cycles. By changing the input parameters the model can be adapted to various types of NiTi-based materials. The model was implemented in the finite element code Abaqus as a User routine and several simulations were performed to validate the implementation

  19. 3D Shape Modeling Using High Level Descriptors

    DEFF Research Database (Denmark)

    Andersen, Vedrana

    features like thorns, bark and scales. Presented here is a simple method for easy modeling, transferring and editing that kind of texture. The method is an extension of the height-field texture, but incorporates an additional tilt of the height field. Related to modeling non-heightfield textures, a part...... of my work involved developing feature-aware resizing of models with complex surfaces consisting of underlying shape and a distinctive texture detail. The aim was to deform an object while preserving the shape and size of the features.......The goal of this Ph.D. project is to investigate and improve the methods for describing the surface of 3D objects, with focus on modeling geometric texture on surfaces. Surface modeling being a large field of research, the work done during this project concentrated around a few smaller areas...

  20. Thermodynamic modelling of shape memory behaviour: some examples

    International Nuclear Information System (INIS)

    Stalmans, R.; Humbeeck, J. van; Delaey, L.

    1995-01-01

    This paper gives a general view of a recently developed thermodynamic model of the thermoelastic martensitic transformation. Unlike existing empirical, mathematical or thermodynamic models, this generalised thermodynamic model can be used to understand and describe quantitatively the overall thermomechanical behaviour of polycrystalline shape memory alloys. Important points of difference between this and previous thermodynamic models are that the contributions of the stored elastic energy and of the crystal defects are also included. In addition, the mathematical approach and the assumptions in this model are selected in such a way that the calculations yield close approximations of the real behaviour and that the final mathematical equations are relatively simple. Several illustrations indicate that this model, in contrast to other models, can be used to understand the shape memory behaviour of complex cases. As an example of quantitative calculations, it is shown that this modelling can be an effective tool in the ''design'' of multifunctional materials consisting of shape memory elements embedded in matrix materials. (orig.)

  1. A three-dimensional constitutive model for shape memory alloy

    International Nuclear Information System (INIS)

    Zhou, Bo; Yoon, Sung-Ho; Leng, Jin-Song

    2009-01-01

    Shape memory alloy (SMA) has a wide variety of practical applications due to its unique super-elasticity and shape memory effect. It is of practical interest to establish a constitutive model which predicts its phase transformation and mechanical behaviors. In this paper, a new three-dimensional phase transformation equation, which predicts the phase transformation behaviors of SMA, is developed based on the results of a differential scanning calorimetry (DSC) test. It overcomes both limitations: that Zhou's phase transformation equations fail to describe the phase transformation from twinned martensite to detwinned martensite of SMA and Brinson's phase transformation equation fails to express the influences of phase transformation peak temperatures on the phase transformation behaviors of SMA. A new three-dimensional constitutive equation, which predicts the mechanical behaviors associated with the super-elasticity and shape memory effect of SMA, is developed on the basis of thermodynamics and solid mechanics. Results of numerical simulations show that the new constitutive model, which includes the new phase transformation equation and constitutive equation, can predict the phase transformation and mechanical behaviors associated with the super-elasticity and shape memory effect of SMA precisely and comprehensively. It is proved that Brinson's constitutive model of SMA can be considered as one special case of the new constitutive model

  2. Polynomial constitutive model for shape memory and pseudo elasticity

    International Nuclear Information System (INIS)

    Savi, M.A.; Kouzak, Z.

    1995-01-01

    This paper reports an one-dimensional phenomenological constitutive model for shape memory and pseudo elasticity using a polynomial expression for the free energy which is based on the classical Devonshire theory. This study identifies the main characteristics of the classical theory and introduces a simple modification to obtain better results. (author). 9 refs., 6 figs

  3. Irregular Shaped Building Design Optimization with Building Information Modelling

    Directory of Open Access Journals (Sweden)

    Lee Xia Sheng

    2016-01-01

    Full Text Available This research is to recognise the function of Building Information Modelling (BIM in design optimization for irregular shaped buildings. The study focuses on a conceptual irregular shaped “twisted” building design similar to some existing sculpture-like architectures. Form and function are the two most important aspects of new buildings, which are becoming more sophisticated as parts of equally sophisticated “systems” that we are living in. Nowadays, it is common to have irregular shaped or sculpture-like buildings which are very different when compared to regular buildings. Construction industry stakeholders are facing stiff challenges in many aspects such as buildability, cost effectiveness, delivery time and facility management when dealing with irregular shaped building projects. Building Information Modelling (BIM is being utilized to enable architects, engineers and constructors to gain improved visualization for irregular shaped buildings; this has a purpose of identifying critical issues before initiating physical construction work. In this study, three variations of design options differing in rotating angle: 30 degrees, 60 degrees and 90 degrees are created to conduct quantifiable comparisons. Discussions are focused on three major aspects including structural planning, usable building space, and structural constructability. This research concludes that Building Information Modelling is instrumental in facilitating design optimization for irregular shaped building. In the process of comparing different design variations, instead of just giving “yes or no” type of response, stakeholders can now easily visualize, evaluate and decide to achieve the right balance based on their own criteria. Therefore, construction project stakeholders are empowered with superior evaluation and decision making capability.

  4. Eight equation model for arbitrary shaped pipe conveying fluid

    International Nuclear Information System (INIS)

    Gale, J.; Tiselj, I.

    2006-01-01

    Linear eight-equation system for two-way coupling of single-phase fluid transient and arbitrary shaped one-dimensional pipeline movement is described and discussed. The governing phenomenon described with this system is also known as Fluid-Structure Interaction. Standard Skalak's four-equation model for axial coupling was improved with additional four Timoshenko's beam equations for description of flexural displacements and rotations. In addition to the conventional eight-equation system that enables coupling of straight sections, the applied mathematical model was improved for description of the arbitrary shaped pipeline located in two-dimensional plane. The applied model was solved with second-order accurate numerical method that is based on Godounov's characteristic upwind schemes. The model was successfully used for simulation of the rod impact induced transient and conventional instantaneous valve closure induced transient in the tank-pipe-valve system. (author)

  5. Rib fractures under anterior-posterior dynamic loads: experimental and finite-element study.

    Science.gov (United States)

    Li, Zuoping; Kindig, Matthew W; Kerrigan, Jason R; Untaroiu, Costin D; Subit, Damien; Crandall, Jeff R; Kent, Richard W

    2010-01-19

    The purpose of this study was to investigate whether using a finite-element (FE) mesh composed entirely of hexahedral elements to model cortical and trabecular bone (all-hex model) would provide more accurate simulations than those with variable thickness shell elements for cortical bone and hexahedral elements for trabecular bone (hex-shell model) in the modeling human ribs. First, quasi-static non-injurious and dynamic injurious experiments were performed using the second, fourth, and tenth human thoracic ribs to record the structural behavior and fracture tolerance of individual ribs under anterior-posterior bending loads. Then, all-hex and hex-shell FE models for the three ribs were developed using an octree-based and multi-block hex meshing approach, respectively. Material properties of cortical bone were optimized using dynamic experimental data and the hex-shell model of the fourth rib and trabecular bone properties were taken from the literature. Overall, the reaction force-displacement relationship predicted by both all-hex and hex-shell models with nodes in the offset middle-cortical surfaces compared well with those measured experimentally for all the three ribs. With the exception of fracture locations, the predictions from all-hex and offset hex-shell models of the second and fourth ribs agreed better with experimental data than those from the tenth rib models in terms of reaction force at fracture (difference rib responses and bone fractures for the loading conditions considered, but coarse hex-shell models with constant or variable shell thickness were more computationally efficient and therefore preferred. Copyright 2009 Elsevier Ltd. All rights reserved.

  6. Orthodontic applications of a superelastic shape-memory alloy model

    International Nuclear Information System (INIS)

    Glendenning, R.W.; Enlow, R.L.

    2000-01-01

    During orthodontic treatment, dental appliances (braces) made of shape memory alloys have the potential to provide nearly uniform low level stresses to dentitions during tooth movement over a large range of tooth displacement. In this paper we model superelastic behaviour of dental appliances using the finite element method and constitutive equations developed by F. Auricchio et al. Results of the mathematical model for 3-point bending and several promising 'closing loop' designs are compared with laboratory results for the same configurations. (orig.)

  7. Modeling the behaviour of shape memory materials under large deformations

    Science.gov (United States)

    Rogovoy, A. A.; Stolbova, O. S.

    2017-06-01

    In this study, the models describing the behavior of shape memory alloys, ferromagnetic materials and polymers have been constructed, using a formalized approach to develop the constitutive equations for complex media under large deformations. The kinematic and constitutive equations, satisfying the principles of thermodynamics and objectivity, have been derived. The application of the Galerkin procedure to the systems of equations of solid mechanics allowed us to obtain the Lagrange variational equation and variational formulation of the magnetostatics problems. These relations have been tested in the context of the problems of finite deformation in shape memory alloys and ferromagnetic materials during forward and reverse martensitic transformations and in shape memory polymers during forward and reverse relaxation transitions from a highly elastic to a glassy state.

  8. First Principles Modelling of Shape Memory Alloys Molecular Dynamics Simulations

    CERN Document Server

    Kastner, Oliver

    2012-01-01

    Materials sciences relate the macroscopic properties of materials to their microscopic structure and postulate the need for holistic multiscale research. The investigation of shape memory alloys is a prime example in this regard. This particular class of materials exhibits strong coupling of temperature, strain and stress, determined by solid state phase transformations of their metallic lattices. The present book presents a collection of simulation studies of this behaviour. Employing conceptually simple but comprehensive models, the fundamental material properties of shape memory alloys are qualitatively explained from first principles. Using contemporary methods of molecular dynamics simulation experiments, it is shown how microscale dynamics may produce characteristic macroscopic material properties. The work is rooted in the materials sciences of shape memory alloys and  covers  thermodynamical, micro-mechanical  and crystallographical aspects. It addresses scientists in these research fields and thei...

  9. Development of an engineering model for ferromagnetic shape memory alloys

    International Nuclear Information System (INIS)

    Tani, Yoshiaki; Todaka, Takashi; Enokizono, Masato

    2008-01-01

    This paper presents a relationship among stress, temperature and magnetic properties of a ferromagnetic shape memory alloy. In order to derive an engineering model of ferromagnetic shape memory alloys, we have developed a measuring system of the relationship among stress, temperature and magnetic properties. The samples used in this measurement are Fe68-Ni10-Cr9-Mn7-Si6 wt% ferromagnetic shape memory alloy. They are thin ribbons made by rapid cooling in air. In the measurement, the ribbon sample is inserted into a sample holder winding consisting of the B-coil and compensation coils, and magnetized in an open solenoid coil. The ribbon is stressed with attachment weights and heated with a heating wire. The specific susceptibility was increased by applying tension, and slightly increased by heating below the Curie temperature

  10. Plastic bowing of the ribs in children

    Energy Technology Data Exchange (ETDEWEB)

    Caro, P.A.; Borden, S. IV

    1988-06-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture.

  11. Plastic bowing of the ribs in children

    International Nuclear Information System (INIS)

    Caro, P.A.; Borden, S. IV

    1988-01-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture. (orig.)

  12. Radar observations and shape model of asteroid 16 Psyche

    Science.gov (United States)

    Shepard, Michael K.; Richardson, James; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Conrad, Al; de Pater, Imke; Adamkovics, Mate; de Kleer, Katherine; Males, Jared R.; Morzinski, Katie M.; Close, Laird M.; Kaasalainen, Mikko; Viikinkoski, Matti; Timerson, Bradley; Reddy, Vishnu; Magri, Christopher; Nolan, Michael C.; Howell, Ellen S.; Benner, Lance A. M.; Giorgini, Jon D.; Warner, Brian D.; Harris, Alan W.

    2017-01-01

    Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50-70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm-3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features.

  13. Asteroid 16 Psyche: Radar Observations and Shape Model

    Science.gov (United States)

    Shepard, Michael K.; Richardson, James E.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Conrad, Al; de Pater, Imke; Adamkovics, Mate; de Kleer, Katherine R.; Males, Jared; Morzinski, Kathleen M.; Miller Close, Laird; Kaasalainen, Mikko; Viikinkoski, Matti; Timerson, Bradley; Reddy, Vishnu; Magri, Christopher; Nolan, Michael C.; Howell, Ellen S.; Warner, Brian D.; Harris, Alan W.

    2016-10-01

    We observed 16 Psyche, the largest M-class asteroid in the main belt, using the S-band radar at Arecibo Observatory. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image [Hanus et al. Icarus 226, 1045-1057, 2013] and three multi-chord occultations. Our shape model has dimensions 279 x 232 x 189 km (±10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves [Hanus et al., 2013]. Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ~50-70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kg m-3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ~40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features.

  14. 3D active shape modeling for cardiac MR and CT image segmentation

    NARCIS (Netherlands)

    Assen, Hans Christiaan van

    2006-01-01

    3D Active Shape Modeling is a technique to capture shape information from a training set containing characteristic shapes of, e.g., a heart. The description contains a mean shape, and shape variations (e.g. eigen deformations and eigen values). Many models based on these statistics, and used for

  15. Bilateral first rib fractures: A case report

    Directory of Open Access Journals (Sweden)

    Dilip Amonkar

    2014-01-01

    Full Text Available From the time first rib fractures were first described in 1869, they have been a source of anxiety to attendant trauma surgeons working in the accident and emergency department of major hospitals. First rib fractures are associated with major thoracic trauma and may involve injury to subclavian vessels, brachial plexus, and mediastinal structures. But these complications are more often seen following unilateral first rib fractures. In contrast, bilateral first rib fractures may follow insignificant trauma, suggesting a different mechanism involved. Serious vascular injuries and brachial plexus injuries are rare and angiograms for evaluation of these patients aren′t routinely warranted. The case that we report illustrates this very point.

  16. Missed rib fractures on evaluation of initial chest CT for trauma patients: pattern analysis and diagnostic value of coronal multiplanar reconstruction images with multidetector row CT.

    Science.gov (United States)

    Cho, S H; Sung, Y M; Kim, M S

    2012-10-01

    The objective of this study was to review the prevalence and radiological features of rib fractures missed on initial chest CT evaluation, and to examine the diagnostic value of additional coronal images in a large series of trauma patients. 130 patients who presented to an emergency room for blunt chest trauma underwent multidetector row CT of the thorax within the first hour during their stay, and had follow-up CT or bone scans as diagnostic gold standards. Images were evaluated on two separate occasions: once with axial images and once with both axial and coronal images. The detection rates of missed rib fractures were compared between readings using a non-parametric method of clustered data. In the cases of missed rib fractures, the shapes, locations and associated fractures were evaluated. 58 rib fractures were missed with axial images only and 52 were missed with both axial and coronal images (p=0.088). The most common shape of missed rib fractures was buckled (56.9%), and the anterior arc (55.2%) was most commonly involved. 21 (36.2%) missed rib fractures had combined fractures on the same ribs, and 38 (65.5%) were accompanied by fracture on neighbouring ribs. Missed rib fractures are not uncommon, and radiologists should be familiar with buckle fractures, which are frequently missed. Additional coronal imagescan be helpful in the diagnosis of rib fractures that are not seen on axial images.

  17. Rib fractures and death from deletion of osteoblast βcatenin in adult mice is rescued by corticosteroids.

    Science.gov (United States)

    Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

    2013-01-01

    Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis.

  18. 2D-3D shape reconstruction of the distal femur from stereo X-Ray imaging using statistical shape models

    DEFF Research Database (Denmark)

    Baka, N.; Kaptein, B. L.; de Bruijne, Marleen

    2011-01-01

    Three-dimensional patient specific bone models are required in a range of medical applications, such as pre-operative surgery planning and improved guidance during surgery, modeling and simulation, and in vivo bone motion tracking. Shape reconstruction from a small number of X-ray images is desired...... as it lowers both the acquisition costs and the radiation dose compared to CT. We propose a method for pose estimation and shape reconstruction of 3D bone surfaces from two (or more) calibrated X-ray images using a statistical shape model (SSM). User interaction is limited to manual initialization of the mean...... pose estimation of ground truth shapes as well as 3D shape estimation using a SSM of the whole femur, from stereo cadaver X-rays, in vivo biplane fluoroscopy image-pairs, and an in vivo biplane fluoroscopic sequence. Ground truth shapes for all experiments were available in the form of CT segmentations...

  19. Experimental investigations on frictional resistance and velocity distribution of rough wall with regularly distributed triangular ribs

    International Nuclear Information System (INIS)

    Motozawa, Masaaki; Ito, Takahiro; Iwamoto, Kaoru; Kawashima, Hideki; Ando, Hirotomo; Senda, Tetsuya; Tsuji, Yoshiyuki; Kawaguchi, Yasuo

    2013-01-01

    Highlights: • Flow over the regularly distributed triangular ribs was investigated. • Simultaneous measurement of flow resistance and velocity profile was performed. • Flow resistance was measured directly and velocity profile was measured by LDV. • Flow resistance was estimated by the information of the velocity field. • Estimated flow resistance has good agreement with the measured flow resistance. -- Abstract: The relationship between the flow resistance of a turbulent flow over triangular ribs regularly distributed on a wall surface and the velocity distribution around the ribs was investigated experimentally. A concentric cylinder device composed of an inner test cylinder and an outer cylinder was employed to measure the flow resistance using the torque of the shaft of the inner cylinder and the velocity distribution of the flow around a rib by laser Doppler velocimetry (LDV) simultaneously. We prepared four inner test cylinders having 4, 8, 12 and 16 triangular ribs on the surface with the same interval between them. Each rib had an isosceles right triangle V-shape and a height of 2 mm. To investigate the relationship between flow resistance and velocity distribution, we estimated the frictional drag and pressure drag acting on the surface of the ribs separately using the velocity distribution. Therefore, we could also estimate the total flow resistance using the velocity distribution. As a result of the experiment, the flow resistance and the attachment point downstream of the rib were shown to depend on the distance between ribs. Moreover, the flow resistance estimated using the velocity distribution had good agreement with the flow resistance measured using the torque of the inner cylinder

  20. Patch-based generative shape model and MDL model selection for statistical analysis of archipelagos

    DEFF Research Database (Denmark)

    Ganz, Melanie; Nielsen, Mads; Brandt, Sami

    2010-01-01

    We propose a statistical generative shape model for archipelago-like structures. These kind of structures occur, for instance, in medical images, where our intention is to model the appearance and shapes of calcifications in x-ray radio graphs. The generative model is constructed by (1) learning ...

  1. Wavefront control performance modeling with WFIRST shaped pupil coronagraph testbed

    Science.gov (United States)

    Zhou, Hanying; Nemati, Bijian; Krist, John; Cady, Eric; Kern, Brian; Poberezhskiy, Ilya

    2017-09-01

    NASA's WFIRST mission includes a coronagraph instrument (CGI) for direct imaging of exoplanets. Significant improvement in CGI model fidelity has been made recently, alongside a testbed high contrast demonstration in a simulated dynamic environment at JPL. We present our modeling method and results of comparisons to testbed's high order wavefront correction performance for the shaped pupil coronagraph. Agreement between model prediction and testbed result at better than a factor of 2 has been consistently achieved in raw contrast (contrast floor, chromaticity, and convergence), and with that comes good agreement in contrast sensitivity to wavefront perturbations and mask lateral shear.

  2. Rib Radiography versus Chest Computed Tomography in the Diagnosis of Rib Fractures.

    Science.gov (United States)

    Sano, Atsushi

    2018-05-01

     The accurate diagnosis of rib fractures is important in chest trauma. Diagnostic images following chest trauma are usually obtained via chest X-ray, chest computed tomography, or rib radiography. This study evaluated the diagnostic characteristics of rib radiography and chest computed tomography.  Seventy-five rib fracture patients who underwent both chest computed tomography and rib radiography between April 2008 and December 2013 were included. Rib radiographs, centered on the site of pain, were taken from two directions. Chest computed tomography was performed using a 16-row multidetector scanner with 5-mm slice-pitch without overlap, and axial images were visualized in a bone window.  In total, 217 rib fractures were diagnosed in 75 patients. Rib radiography missed 43 rib fractures in 24 patients. The causes were overlap with organs in 15 cases, trivial fractures in 21 cases, and injury outside the imaging range in 7 cases. Left lower rib fractures were often missed due to overlap with the heart, while middle and lower rib fractures were frequently not diagnosed due to overlap with abdominal organs. Computed tomography missed 21 rib fractures in 17 patients. The causes were horizontal fractures in 10 cases, trivial fractures in 9 cases, and insufficient breath holding in 1 case.  In rib radiography, overlap with organs and fractures outside the imaging range were characteristic reasons for missed diagnoses. In chest computed tomography, horizontal rib fractures and insufficient breath holding were often responsible. We should take these challenges into account when diagnosing rib fractures. Georg Thieme Verlag KG Stuttgart · New York.

  3. Turbulent heat transfer and nanofluid flow in a protruded ribbed square passage

    Science.gov (United States)

    Kumar, Sunil; Kothiyal, Alok Darshan; Bisht, Mangal Singh; Kumar, Anil

    In this article, turbulent heat transfer of nanofluid flow in square passage with protruded rib shape is numerically and experimentally studied over Reynolds number ranges of 4000-18000. Different nanoparticles (Al2O3, CuO, and ZnO), with different concentration (φ) range of 1-4% and different nanoparticle diameter (dnp) range of 30-45 nm are disperse in water (base fluid). Several parameters such as stream wise distance (Xs /dp) range of 1.4-2.6, span wise distance (Ys /dp) range of 1.4-2.6, ratio of protruded height to print diameter (ep /dp) range of 0.83-1.67 also studied to find the consequence on thermal and hydrodynamic characteristics. Simulations were carried out to obtain heat and fluid flow behaviour of smooth and ribbed square channel using commercial CFD software, ANSYS 15.0 (Fluent). Renormalization k - ε model was employed to assess the influence of protruded ribs on turbulent flow and velocity field. The outcome indicates that Al2O3 nanofluid has the highest value of average Nusselt number as compare to other nanofluids. The average Nusselt number increases as the concentration increases and it decreases as nanoparticle diameter increases. The thermal hydrodynamic performance parameter based on equal pumping power, average Nusselt number and average friction factor were found to be highest for Al2O3, φ = 0.04, dnp = 30 nm, Xs /dp = 1.8, Ys /dp = 1.8 and ep /dp = 1.0 . The numerical data are compared with the corresponding experimental data. Comparison between CFD and experimental analysis results showed that good agreement as the data fell within ±7.0% error band.

  4. A macroscopic model for magnetic shape-memory single crystals

    Czech Academy of Sciences Publication Activity Database

    Bessoud, A. L.; Kružík, Martin; Stefanelli, U.

    2013-01-01

    Roč. 64, č. 2 (2013), s. 343-359 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GAP201/10/0357 Institutional support: RVO:67985556 Keywords : magnetostriction * evolution Subject RIV: BA - General Mathematics Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-a macroscopic model for magnetic shape- memory single crystals.pdf

  5. Rock shape, restitution coefficients and rockfall trajectory modelling

    Science.gov (United States)

    Glover, James; Christen, Marc; Bühler, Yves; Bartelt, Perry

    2014-05-01

    Restitution coefficients are used in rockfall trajectory modelling to describe the ratio between incident and rebound velocities during ground impact. They are central to the problem of rockfall hazard analysis as they link rock mass characteristics to terrain properties. Using laboratory experiments as a guide, we first show that restitution coefficients exhibit a wide range of scatter, although the material properties of the rock and ground are constant. This leads us to the conclusion that restitution coefficients are poor descriptors of rock-ground interaction. The primary problem is that "apparent" restitution coefficients are applied at the rock's centre-of-mass and do not account for rock shape. An accurate description of the rock-ground interaction requires the contact forces to be applied at the rock surface with consideration of the momentary rock position and spin. This leads to a variety of rock motions including bouncing, sliding, skipping and rolling. Depending on the impact configuration a wide range of motions is possible. This explains the large scatter of apparent restitution coefficients. We present a rockfall model based on newly developed hard-contact algorithms which includes the effects of rock shape and therefore is able to reproduce the results of different impact configurations. We simulate the laboratory experiments to show that it is possible to reproduce run-out and dispersion of different rock shapes using parameters obtained from independent tests. Although this is a step forward in rockfall trajectory modelling, the problem of parametersing real terrain remains.

  6. PICTORIAL INTERLUDE Beware the bifid rib!

    African Journals Online (AJOL)

    be associated with Gorlin-Goltz basal cell nevus syndrome, a rare autosomal dominant condition characterised by multiple nevoid basal cell carcinomas, jaw cysts and bifid ribs. Further features include other rib anomalies, deficiency of the lateral clavicle, mandibular hypoplasia, macrocephaly and mental retardation.1.

  7. Scoliosis secondary to an unusual rib lesion.

    LENUS (Irish Health Repository)

    Burke, N G

    2012-04-01

    Tumours of the chest wall are uncommon and are usually malignant. A bone haemangioma is a rare benign vascular neoplasm, which more commonly occurs in middle-aged patients. We present the case of a scoliosis caused by a rib haemangioma in an adolescent male. Other causes of scoliosis secondary to rib lesions are discussed.

  8. Automated robust generation of compact 3D statistical shape models

    Science.gov (United States)

    Vrtovec, Tomaz; Likar, Bostjan; Tomazevic, Dejan; Pernus, Franjo

    2004-05-01

    Ascertaining the detailed shape and spatial arrangement of anatomical structures is important not only within diagnostic settings but also in the areas of planning, simulation, intraoperative navigation, and tracking of pathology. Robust, accurate and efficient automated segmentation of anatomical structures is difficult because of their complexity and inter-patient variability. Furthermore, the position of the patient during image acquisition, the imaging device and protocol, image resolution, and other factors induce additional variations in shape and appearance. Statistical shape models (SSMs) have proven quite successful in capturing structural variability. A possible approach to obtain a 3D SSM is to extract reference voxels by precisely segmenting the structure in one, reference image. The corresponding voxels in other images are determined by registering the reference image to each other image. The SSM obtained in this way describes statistically plausible shape variations over the given population as well as variations due to imperfect registration. In this paper, we present a completely automated method that significantly reduces shape variations induced by imperfect registration, thus allowing a more accurate description of variations. At each iteration, the derived SSM is used for coarse registration, which is further improved by describing finer variations of the structure. The method was tested on 64 lumbar spinal column CT scans, from which 23, 38, 45, 46 and 42 volumes of interest containing vertebra L1, L2, L3, L4 and L5, respectively, were extracted. Separate SSMs were generated for each vertebra. The results show that the method is capable of reducing the variations induced by registration errors.

  9. Visualization of the variability of 3D statistical shape models by animation.

    Science.gov (United States)

    Lamecker, Hans; Seebass, Martin; Lange, Thomas; Hege, Hans-Christian; Deuflhard, Peter

    2004-01-01

    Models of the 3D shape of anatomical objects and the knowledge about their statistical variability are of great benefit in many computer assisted medical applications like images analysis, therapy or surgery planning. Statistical model of shapes have successfully been applied to automate the task of image segmentation. The generation of 3D statistical shape models requires the identification of corresponding points on two shapes. This remains a difficult problem, especially for shapes of complicated topology. In order to interpret and validate variations encoded in a statistical shape model, visual inspection is of great importance. This work describes the generation and interpretation of statistical shape models of the liver and the pelvic bone.

  10. Orthodontic applications of a superelastic shape-memory alloy model

    Energy Technology Data Exchange (ETDEWEB)

    Glendenning, R.W.; Enlow, R.L. [Otago Univ., Dunedin (New Zealand). Dept. of Math. and Stat.; Hood, J.A.A. [Dept. of Oral Sciences and Orthodontics, Univ. of Otago, Dunedin (New Zealand)

    2000-07-01

    During orthodontic treatment, dental appliances (braces) made of shape memory alloys have the potential to provide nearly uniform low level stresses to dentitions during tooth movement over a large range of tooth displacement. In this paper we model superelastic behaviour of dental appliances using the finite element method and constitutive equations developed by F. Auricchio et al. Results of the mathematical model for 3-point bending and several promising 'closing loop' designs are compared with laboratory results for the same configurations. (orig.)

  11. Nozzle airfoil having movable nozzle ribs

    Science.gov (United States)

    Yu, Yufeng Phillip; Itzel, Gary Michael

    2002-01-01

    A nozzle vane or airfoil structure is provided in which the nozzle ribs are connected to the side walls of the vane or airfoil in such a way that the ribs provide the requisite mechanical support between the concave side and convex side of the airfoil but are not locked in the radial direction of the assembly, longitudinally of the airfoil. The ribs may be bi-cast onto a preformed airfoil side wall structure or fastened to the airfoil by an interlocking slide connection and/or welding. By attaching the nozzle ribs to the nozzle airfoil metal in such a way that allows play longitudinally of the airfoil, the temperature difference induced radial thermal stresses at the nozzle airfoil/rib joint area are reduced while maintaining proper mechanical support of the nozzle side walls.

  12. Numerical simulations of heat transfer distribution of a two-pass square channel with V-rib turbulator and bleed holes

    Science.gov (United States)

    Kumar, Sourabh; Amano, R. S.; Lucci, Jose Martinez

    2013-08-01

    The blade tip region in gas turbine encounters high thermal loads due to temperature difference and hence efforts for high durability and safe operations are essential. Improved and robust methods of cooling are required to downgrade heat transfer rate to turbine blades. The blade tip regions, which are exposed to high gas flow, suffers high local thermal load which are due to external tip leakage. Jet impingement, pin cooling etc. are techniques used for cooling blades. A more usual way is to use serpentine passage with 180-degree turn. In this study, numerical simulation of heat transfer distribution of a two-pass square channel with rib turbulators and bleed holes were done. Periodical rib turbulators and bleed holes were used in the channel. The ribs arrangement were 60 degree V rib, 60 degree inverted V ribs, combination of 60 degree V rib at inlet and 60 inverted V rib at outlet section and combination of Inverted V at inlet and V rib at the outlet. The results were numerically computed using Fluent with Reynolds number of 12,500 and 28,500. Turbulence models used for computations were k-ω-SST and RSM. Temperature based and shear stress based techniques were used for heat transfer distribution prediction. The results for 60 degree V rib, 60 degree inverted V ribs were compared with the experimental results for validation of the results obtained. Detailed distribution shows distinctive peaks in heat transfer around bleed holes and rib turbulator. Comparisons of the overall performance of the models with different orientation of rib turbulator are presented. It is found that due to the combination of 60 degree inverted V rib in inlet and 60 V rib in outlet with bleed holes provides better heat treatment. It is suggested that the use of rib turbulator with bleed holes provides suitable for augmenting blade cooling to achieve an optimal balance between thermal and mechanical design requirements.

  13. Modeling Macroscopic Shape Distortions during Sintering of Multi-layers

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye

    as to help achieve defect free multi-layer components. The initial thickness ratio between the layers making the multi-layer has also significant effect on the extent of camber evolution depending on the material systems. During sintering of tubular bi-layer structures, tangential (hoop) stresses are very...... large compared to radial stresses. The maximum value of hoop stress, which can generate processing defects such as cracks and coating peel-offs, occurs at the beginning of the sintering cycle. Unlike most of the models defining material properties based on porosity and grain size only, the multi...... (firing). However, unintended features like shape instabilities of samples, cracks or delamination of layers may arise during sintering of multi-layer composites. Among these defects, macroscopic shape distortions in the samples can cause problems in the assembly or performance of the final component...

  14. Intercostal high intensity focused ultrasound for liver ablation: The influence of beam shaping on sonication efficacy and near-field risks

    Energy Technology Data Exchange (ETDEWEB)

    Greef, M. de, E-mail: m.degreef@umcutrecht.nl; Wijlemans, J. W.; Bartels, L. W.; Moonen, C. T. W.; Ries, M. [Imaging Division, University Medical Center Utrecht, Utrecht 3508GA (Netherlands); Schubert, G.; Koskela, J. [Philips Healthcare, Vantaa FI-01511 (Finland)

    2015-08-15

    Purpose: One of the major issues in high intensity focused ultrasound ablation of abdominal lesions is obstruction of the ultrasound beam by the thoracic cage. Beam shaping strategies have been shown by several authors to increase focal point intensity while limiting rib exposure. However, as rib obstruction leaves only part of the aperture available for energy transmission, conserving total emitted acoustic power, the intensity in the near-field tissues inherently increases after beam shaping. Despite of effective rib sparing, those tissues are therefore subjected to increased risk of thermal damage. In this study, for a number of clinically representative intercostal sonication geometries, modeling clinically available hardware, the effect of beam shaping on both the exposure of the ribs and near-field to acoustic energy was evaluated and the implications for the volumetric ablation rate were addressed. Methods: A relationship between rib temperature rise and acoustic energy density was established by means of in vivo MR thermometry and simulations of the incident acoustic energy for the corresponding anatomies. This relationship was used for interpretation of rib exposure in subsequent numerical simulations in which rib spacing, focal point placement, and the focal point trajectory were varied. The time required to heat a targeted region to 65 °C was determined without and with the application of beam shaping. The required sonication time was used to calculate the acoustic energy density at the fat–muscle interface and at the surface of the ribs. At the fat–muscle interface, exposure was compared to available literature data and rib exposure was interpreted based on the earlier obtained relation between measured temperature rise and simulated acoustic energy density. To estimate the volumetric ablation rate, the cool-down time between periods of energy exposure was estimated using a time-averaged power limit of 100 kJ/h. Results: At the level of the ribs

  15. Aeroelastic Modeling of Elastically Shaped Aircraft Concept via Wing Shaping Control for Drag Reduction

    Science.gov (United States)

    Nguyen, Nhan; James Urnes, Sr.

    2012-01-01

    Lightweight aircraft design has received a considerable attention in recent years as a means for improving cruise efficiency. Reducing aircraft weight results in lower lift requirements which directly translate into lower drag, hence reduced engine thrust requirements during cruise. The use of lightweight materials such as advanced composite materials has been adopted by airframe manufacturers in current and future aircraft. Modern lightweight materials can provide less structural rigidity while maintaining load-carrying capacity. As structural flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. Abstract This paper describes a recent aeroelastic modeling effort for an elastically shaped aircraft concept (ESAC). The aircraft model is based on the rigid-body generic transport model (GTM) originally developed at NASA Langley Research Center. The ESAC distinguishes itself from the GTM in that it is equipped with highly flexible wing structures as a weight reduction design feature. More significantly, the wings are outfitted with a novel control effector concept called variable camber continuous trailing edge (VCCTE) flap system for active control of wing aeroelastic deflections to optimize the local angle of attack of wing sections for improved aerodynamic efficiency through cruise drag reduction and lift enhancement during take-off and landing. The VCCTE flap is a multi-functional and aerodynamically efficient device capable of achieving high lift-to-drag ratios. The flap system is comprised of three chordwise segments that form the variable camber feature of the flap and multiple spanwise segments that form a piecewise continuous trailing edge. By configuring the flap camber and trailing edge shape, drag reduction could be

  16. Experimental Modeling of the Formation of Saucer-Shaped sills

    Science.gov (United States)

    Galland, O.; Planke, S.; Malthe-Sorenssen, A.

    2007-12-01

    Many magma intrusions in sedimentary basins are sills, and especially saucer-shaped sills. These features are observed in many places (i.e. South Africa; the Norwegian and North Sea; Siberia; Argentina). Sand injectites exhibit similar geometries. The occurrence of such features in so various settings suggests that their emplacement results from fundamental processes in sedimentary basins. To understand such processes, we performed experimental modeling of saucer-shaped sill emplacement. The experiments consist of injecting a molten low viscosity vegetable oil (model magma) at a constant flow rate into a fine-grained Coulomb silica flour (model rock). When the oil starts intruding, the initially flat surface of the model inflates and forms a smooth dome. At the end of the experiment, the oil erupts at the edge of the dome. After the experiment, the oil cools and solidifies, the resulting solid intrusion is unburied and exposed, and its upper surface digitalized. For our purpose, we did our experiments without external deformation. We performed two series of experiments with varying depth of injection. The first series consisted of injection into a homogeneous medium. The resulting intrusions were cone-sheets and dykes. The second series consisted of heterogeneous models where the heterogeneity was a weak layer made of a flexible net. The resulting intrusions were made of (1) a horizontal basal sill emplaced along the weakness, and (2) inclined sheets nucleating at the edges of the basal sill and propagating upward and outward. The inclined sheets exhibited a convex shape, i.e. a decreasing slope outward. In addition, the deeper the sills emplaced, the larger they were. Our experimental results are consistent with saucer-shaped features in nature. We infer from our results that the transition between the basal sills and the inclined sheets results from a transition of emplacement processes. We suggest that the basal sill emplace by open (mode I) fracturing, whereas

  17. Hydrodynamics and Heat Transfer in Flow over Rectangular Ribs on the Initially Smooth Surface

    Directory of Open Access Journals (Sweden)

    V. N. Afanasiev

    2017-01-01

    Full Text Available An efficiency of the heat exchange equipment and reducing their weight and size parameters can be considerably improved by using the optimal methods of heat transfer enhancement, which include a two-dimensional roughness, i.e. ribs, backward-facing steps, cavities, etc. deposited on the heat transfer surface. Their shape, sizes and positional relationship have a significant impact on the structure of the boundary layer and its exchange processes.As known, the most affordable and effective method of controlled influence on the structure of turbulent flow is to create a separation zone or other organized vortex structure in it. In order to successfully use the separation zone, it is necessary to know the mechanism of their interaction with the main turbulent flow and the mechanism of the process in separation zone itself. Heat transfer enhancement is provided mainly due to roughness impact on hydrodynamics of turbulent flow, if the rib height h does not exceed the thickness of the viscous sublayer, since heat transfer enhancement arises from breaking and destruction of viscous sublayer produced by the roughness ribs and emerging vortex zones – sources of turbulence. Usually, the height of ribs y+ ≈ 50, and the distance between them along the streamlined surface is 10-20 times greater. The coefficient of friction also increases, but if the height of ribs is sufficiently small and most of them are in the sublayer, the increase of the friction factor will not exceed the increase of the heat transfer coefficient.The paper presents results of experimental investigation of hydrodynamics and heat transfer in the separation zone before and after a rib and in the area of two rectangular ribs with the height of y+ £ 60. The ribs are placed on the flat plate and heated according to the law of qw = const. The structure of turbulent boundary layer from the standpoint of the universal logarithmic law of velocity distribution has been experimentally

  18. ACR Appropriateness Criteria® rib fractures.

    Science.gov (United States)

    Henry, Travis S; Kirsch, Jacobo; Kanne, Jeffrey P; Chung, Jonathan H; Donnelly, Edwin F; Ginsburg, Mark E; Heitkamp, Darel E; Kazerooni, Ella A; Ketai, Loren H; McComb, Barbara L; Parker, J Anthony; Ravenel, James G; Restrepo, Carlos Santiago; Saleh, Anthony G; Shah, Rakesh D; Steiner, Robert M; Suh, Robert D; Mohammed, Tan-Lucien H

    2014-11-01

    Rib fracture is the most common thoracic injury, present in 10% of all traumatic injuries and almost 40% of patients who sustain severe nonpenetrating trauma. Although rib fractures can produce significant morbidity, the diagnosis of associated complications (such as pneumothorax, hemothorax, pulmonary contusion, atelectasis, flail chest, cardiovascular injury, and injuries to solid and hollow abdominal organs) may have a more significant clinical impact. When isolated, rib fractures have a relatively low morbidity and mortality, and failure to detect isolated rib fractures does not necessarily alter patient management or outcome in uncomplicated cases. A standard posteroanterior chest radiograph should be the initial, and often the only, imaging test required in patients with suspected rib fracture after minor trauma. Detailed radiographs of the ribs rarely add additional information that would change treatment, and, although other imaging tests (eg, computed tomography, bone scan) have increased sensitivity for detection of rib fractures, there are little data to support their use. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review process include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

  19. Rib Fracture Fixation: Indications and Outcomes.

    Science.gov (United States)

    Senekjian, Lara; Nirula, Raminder

    2017-01-01

    Rib fractures are a frequently identified injury in the trauma population. Not only are multiple rib fractures painful, but they are associated with an increased risk of adverse outcomes. Pneumonia in particular can be devastating, especially to an elderly patient, but other complications such as prolonged ventilation and increased intensive care and hospital durations of stay have a negative impact on the patient. Computed tomography scan is the best modality to diagnosis rib fractures but the treatment of fractures is still evolving. Currently patient care involves a multidisciplinary approach that includes pain control, aggressive pulmonary therapy, and possibly surgical fixation. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Modelling and calibration of a ring-shaped electrostatic meter

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jianyong [University of Teesside, Middlesbrough TS1 3BA (United Kingdom); Zhou Bin; Xu Chuanlong; Wang Shimin, E-mail: zhoubinde1980@gmail.co [Southeast University, Sipailou 2, Nanjing 210096 (China)

    2009-02-01

    Ring-shaped electrostatic flow meters can provide very useful information on pneumatically transported air-solids mixture. This type of meters are popular in measuring and controlling the pulverized coal flow distribution among conveyors leading to burners in coal-fired power stations, and they have also been used for research purposes, e.g. for the investigation of electrification mechanism of air-solids two-phase flow. In this paper, finite element method (FEM) is employed to analyze the characteristics of ring-shaped electrostatic meters, and a mathematic model has been developed to express the relationship between the meter's voltage output and the motion of charged particles in the sensing volume. The theoretical analysis and the test results using a belt rig demonstrate that the output of the meter depends upon many parameters including the characteristics of conditioning circuitry, the particle velocity vector, the amount and the rate of change of the charge carried by particles, the locations of particles and etc. This paper also introduces a method to optimize the theoretical model via calibration.

  1. Abdomen and spinal cord segmentation with augmented active shape models.

    Science.gov (United States)

    Xu, Zhoubing; Conrad, Benjamin N; Baucom, Rebeccah B; Smith, Seth A; Poulose, Benjamin K; Landman, Bennett A

    2016-07-01

    Active shape models (ASMs) have been widely used for extracting human anatomies in medical images given their capability for shape regularization of topology preservation. However, sensitivity to model initialization and local correspondence search often undermines their performances, especially around highly variable contexts in computed-tomography (CT) and magnetic resonance (MR) images. In this study, we propose an augmented ASM (AASM) by integrating the multiatlas label fusion (MALF) and level set (LS) techniques into the traditional ASM framework. Using AASM, landmark updates are optimized globally via a region-based LS evolution applied on the probability map generated from MALF. This augmentation effectively extends the searching range of correspondent landmarks while reducing sensitivity to the image contexts and improves the segmentation robustness. We propose the AASM framework as a two-dimensional segmentation technique targeting structures with one axis of regularity. We apply AASM approach to abdomen CT and spinal cord (SC) MR segmentation challenges. On 20 CT scans, the AASM segmentation of the whole abdominal wall enables the subcutaneous/visceral fat measurement, with high correlation to the measurement derived from manual segmentation. On 28 3T MR scans, AASM yields better performances than other state-of-the-art approaches in segmenting white/gray matter in SC.

  2. Hysteresis behaviour of thermoelastic alloys: some shape memory alloys models

    International Nuclear Information System (INIS)

    Lexcellent, C.; Torra, V.; Raniecki, B.

    1993-01-01

    The hysteretic behaviour of shape memory alloys (SMA) needs a more and more thin analysis because of its importance for technological applications. The comparison between different approaches allows to explicite the specifity of every model (macroscopic approach, micro-macro level, local description, phenomenological approach) and their points of convergence. On one hand, a thermodynamic treatment with a free energy expression as a mixing rule of each phase (parent or austenite phase and martensite) by adding a coupling term: the configurational energy, allowes modelling of material hysteresis loops. On the other hand, a phenomenological treatment based on a local investigation of two single crystals with a visualisation of microscopic parameters allows to perceive the phase transition mechanisms (nucleation, growth). All the obtained results show the importance of entropy production (or of the definition of the configurational energy term) for the correct description of hysteresis loops (subloops or external). (orig.)

  3. Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

    DEFF Research Database (Denmark)

    Wang, Lei; Salewski, Mirko; Sundén, Bengt

    2010-01-01

    PIV measurements are performed in a channel with periodic ribs on one wall. The emphasis of this study is to investigate the flow structures in the vicinity of a rib in terms of mean velocities, Reynolds stresses, probability density functions (PDF), and two-point correlations. The PDF distribution......-based visualization is applied to the separation bubble upstream of the rib. Salient critical points and limit cycles are extracted, which gives clues to the physical processes occurring in the flow....

  4. Statistical Shape Modelling and Markov Random Field Restoration (invited tutorial and exercise)

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen

    This tutorial focuses on statistical shape analysis using point distribution models (PDM) which is widely used in modelling biological shape variability over a set of annotated training data. Furthermore, Active Shape Models (ASM) and Active Appearance Models (AAM) are based on PDMs and have proven...... deformation field between shapes. The tutorial demonstrates both generative active shape and appearance models, and MRF restoration on 3D polygonized surfaces. ''Exercise: Spectral-Spatial classification of multivariate images'' From annotated training data this exercise applies spatial image restoration...... using Markov random field relaxation of a spectral classifier. Keywords: the Ising model, the Potts model, stochastic sampling, discriminant analysis, expectation maximization....

  5. Novel classification system of rib fractures observed in infants.

    Science.gov (United States)

    Love, Jennifer C; Derrick, Sharon M; Wiersema, Jason M; Pinto, Deborrah C; Greeley, Christopher; Donaruma-Kwoh, Marcella; Bista, Bibek

    2013-03-01

    Rib fractures are considered highly suspicious for nonaccidental injury in the pediatric clinical literature; however, a rib fracture classification system has not been developed. As an aid and impetus for rib fracture research, we developed a concise schema for classifying rib fracture types and fracture location that is applicable to infants. The system defined four fracture types (sternal end, buckle, transverse, and oblique) and four regions of the rib (posterior, posterolateral, anterolateral, and anterior). It was applied to all rib fractures observed during 85 consecutive infant autopsies. Rib fractures were found in 24 (28%) of the cases. A total of 158 rib fractures were identified. The proposed schema was adequate to classify 153 (97%) of the observed fractures. The results indicate that the classification system is sufficiently robust to classify rib fractures typically observed in infants and should be used by researchers investigating infant rib fractures. © 2013 American Academy of Forensic Sciences.

  6. Pulmonary embolism developing after rib fracture

    Directory of Open Access Journals (Sweden)

    Manabu Nemoto

    2014-04-01

    Full Text Available In this letter, we wanted to show that acute pulmonary embolism may be observed as a complication in patients with traumatic rib fracture and to emphasize on the importance the early diagnosis examinations in suspicious cases.

  7. Corrosion of Spiral Rib Aluminized Pipe : [Summary

    Science.gov (United States)

    2012-01-01

    Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

  8. Corrosion of Spiral Rib Aluminized Pipe

    Science.gov (United States)

    2012-08-01

    Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

  9. Flow separation on transversal ribs in an open channel

    Czech Academy of Sciences Publication Activity Database

    Příhoda, Jaromír; Šulc, J.; Sedlář, M.; Zubík, P.

    2009-01-01

    Roč. 13, - (2009), s. 218-220 ISSN 1335-2938. [Stretnutie katedier mechaniky tekutín a termomechaniky. Jasná, Demanovská dolina, 24.06.2009-26.06.2009] R&D Projects: GA ČR GA103/09/0977 Institutional research plan: CEZ:AV0Z20760514 Keywords : free-surface flow * supercritical flow over ribs * numerical and experimental modelling Subject RIV: BK - Fluid Dynamics

  10. Reports on various anomalies of the ribs

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, G.; Brix, F.

    1988-02-01

    Three patients are presented who were suffering from different anomalies of the ribs: There was one each plus and minus variant and a female patient with Gorlin-Goltz syndrome (basal cell nevus syndrome) demonstrating several changes in the ribs as an expression of a genetically determined segmentation disturbance. These presentations are followed by a detailed discussion on the types and causes of such anomalies.

  11. Reports on various anomalies of the ribs

    International Nuclear Information System (INIS)

    Brinkmann, G.; Brix, F.

    1988-01-01

    Three patients are presented who were suffering from different anomalies of the ribs: There was one each plus and minus variant and a female patient with Gorlin-Goltz syndrome (basal cell nevus syndrome) demonstrating several changes in the ribs as an expression of a genetically determined segmentation disturbance. These presentations are followed by a detailed discussion on the types and causes of such anomalies. (orig.) [de

  12. Circular blurred shape model for multiclass symbol recognition.

    Science.gov (United States)

    Escalera, Sergio; Fornés, Alicia; Pujol, Oriol; Lladós, Josep; Radeva, Petia

    2011-04-01

    In this paper, we propose a circular blurred shape model descriptor to deal with the problem of symbol detection and classification as a particular case of object recognition. The feature extraction is performed by capturing the spatial arrangement of significant object characteristics in a correlogram structure. The shape information from objects is shared among correlogram regions, where a prior blurring degree defines the level of distortion allowed in the symbol, making the descriptor tolerant to irregular deformations. Moreover, the descriptor is rotation invariant by definition. We validate the effectiveness of the proposed descriptor in both the multiclass symbol recognition and symbol detection domains. In order to perform the symbol detection, the descriptors are learned using a cascade of classifiers. In the case of multiclass categorization, the new feature space is learned using a set of binary classifiers which are embedded in an error-correcting output code design. The results over four symbol data sets show the significant improvements of the proposed descriptor compared to the state-of-the-art descriptors. In particular, the results are even more significant in those cases where the symbols suffer from elastic deformations.

  13. Effect of Aspect Ratio, Channel Orientation, Rib Pitch-to-Height Ratio, and Number of Ribbed Walls on Pressure Drop Characteristics in a Rotating Channel with Detached Ribs

    Directory of Open Access Journals (Sweden)

    K. Arun

    2007-01-01

    Full Text Available The present work involves experimental investigation of the effects of aspect ratio, channel orientation angle, rib pitch-to-height ratio (P/e, and number of ribbed walls on friction factor in orthogonally rotating channel with detached ribs. The ribs are separated from the base wall to provide a small region of flow between the base wall and the ribs. Experiments have been conducted at Reynolds number ranging from 10000–17000 with rotation numbers varying from 0–0.38. Pitch-to-rib height ratios (P/e of 5 and 10 at constant rib height-to-hydraulic diameter ratio (e/D of 0.1 and a clearance ratio (C/e of 0.38 are considered. The rib angle of attack with respect to mainstream flow is 90∘. The channel orientation at which the ribbed wall becomes trailing surface (pressure side on which the Coriolis force acts is considered as the 0∘ orientation angle. For one-wall ribbed case, channel is oriented from 0∘ to 180∘ about its axis in steps of 30∘ to change the orientation angle. For two-wall ribbed case, the orientation angle is changed from 0∘ to 90∘ in steps of 30∘. Friction factors for the detached ribbed channels are compared with the corresponding attached ribbed channel. It is found that in one-wall detached ribbed channel, increase in the friction factor ratio with the orientation angle is lower for rectangular channel compared to that of square channel for both the pitch-to-rib height ratios of 5 and 10 at a given Reynolds number and rotation number. Friction factor ratios of two-wall detached ribbed rectangular channel are comparable with corresponding two-wall detached ribbed square channel both under stationary and rotating conditions.

  14. Automatic shape model building based on principal geodesic analysis bootstrapping

    DEFF Research Database (Denmark)

    Dam, Erik B; Fletcher, P Thomas; Pizer, Stephen M

    2008-01-01

    iteration are used. Thereby, we gradually capture the shape variation in the training collection better and better. Convergence of the method is explicitly enforced. The method is evaluated on collections of artificial training shapes where the expected shape mean and modes of variation are known by design...

  15. Thermomechanical model for NiTi shape memory wires

    Czech Academy of Sciences Publication Activity Database

    Frost, Miroslav; Sedlák, Petr; Sippola, M.; Šittner, Petr

    2010-01-01

    Roč. 19, č. 9 (2010), s. 1-10 ISSN 0964-1726 R&D Projects: GA MŠk(CZ) 1M06031; GA ČR(CZ) GA106/09/1573; GA ČR(CZ) GP106/09/P302; GA ČR GAP108/10/1296 Institutional research plan: CEZ:AV0Z20760514; CEZ:AV0Z10100520 Keywords : shape memory alloys * modeling * proportional loading Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.094, year: 2010 http://apps.isiknowledge.com/full_record.do?product=WOS&search_mode=GeneralSearch&qid=3&SID=U2fe5mHN9p3gHClCdF1&page=1&doc=1

  16. Smooth extrapolation of unknown anatomy via statistical shape models

    Science.gov (United States)

    Grupp, R. B.; Chiang, H.; Otake, Y.; Murphy, R. J.; Gordon, C. R.; Armand, M.; Taylor, R. H.

    2015-03-01

    Several methods to perform extrapolation of unknown anatomy were evaluated. The primary application is to enhance surgical procedures that may use partial medical images or medical images of incomplete anatomy. Le Fort-based, face-jaw-teeth transplant is one such procedure. From CT data of 36 skulls and 21 mandibles separate Statistical Shape Models of the anatomical surfaces were created. Using the Statistical Shape Models, incomplete surfaces were projected to obtain complete surface estimates. The surface estimates exhibit non-zero error in regions where the true surface is known; it is desirable to keep the true surface and seamlessly merge the estimated unknown surface. Existing extrapolation techniques produce non-smooth transitions from the true surface to the estimated surface, resulting in additional error and a less aesthetically pleasing result. The three extrapolation techniques evaluated were: copying and pasting of the surface estimate (non-smooth baseline), a feathering between the patient surface and surface estimate, and an estimate generated via a Thin Plate Spline trained from displacements between the surface estimate and corresponding vertices of the known patient surface. Feathering and Thin Plate Spline approaches both yielded smooth transitions. However, feathering corrupted known vertex values. Leave-one-out analyses were conducted, with 5% to 50% of known anatomy removed from the left-out patient and estimated via the proposed approaches. The Thin Plate Spline approach yielded smaller errors than the other two approaches, with an average vertex error improvement of 1.46 mm and 1.38 mm for the skull and mandible respectively, over the baseline approach.

  17. Statistical shape modeling based renal volume measurement using tracked ultrasound

    Science.gov (United States)

    Pai Raikar, Vipul; Kwartowitz, David M.

    2017-03-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the fourth most common cause of kidney transplant worldwide accounting for 7-10% of all cases. Although ADPKD usually progresses over many decades, accurate risk prediction is an important task.1 Identifying patients with progressive disease is vital to providing new treatments being developed and enable them to enter clinical trials for new therapy. Among other factors, total kidney volume (TKV) is a major biomarker predicting the progression of ADPKD. Consortium for Radiologic Imaging Studies in Polycystic Kidney Disease (CRISP)2 have shown that TKV is an early, and accurate measure of cystic burden and likely growth rate. It is strongly associated with loss of renal function.3 While ultrasound (US) has proven as an excellent tool for diagnosing the disease; monitoring short-term changes using ultrasound has been shown to not be accurate. This is attributed to high operator variability and reproducibility as compared to tomographic modalities such as CT and MR (Gold standard). Ultrasound has emerged as one of the standout modality for intra-procedural imaging and with methods for spatial localization has afforded us the ability to track 2D ultrasound in physical space which it is being used. In addition to this, the vast amount of recorded tomographic data can be used to generate statistical shape models that allow us to extract clinical value from archived image sets. In this work, we aim at improving the prognostic value of US in managing ADPKD by assessing the accuracy of using statistical shape model augmented US data, to predict TKV, with the end goal of monitoring short-term changes.

  18. Numerical analysis of developing turbulent flow in a U-bend of strong curvature with rib-roughened walls

    International Nuclear Information System (INIS)

    Sugiyama, Hitoshi; Watanabe, Chiriki

    2003-01-01

    Numerical analysis has been performed for three-dimensional developing turbulent flow in the U-bend of strong curvature with rib-roughened walls by using an algebraic Reynolds stress model. In this calculation, the algebraic Reynolds stress model is adopted in order to predict preciously Reynolds stresses and boundary fitted-coordinate system is introduced as the method for coordinate transformation to set exactly boundary conditions along complicated shape in rib-roughed walls. Calculated results of mean velocity and Reynolds stresses are compared with the experimental data in order to examine the validity of the presented numerical method and the algebraic Reynolds stress model. It has been pointed out as a characteristic feature from the experimental result that the maximum velocity appears near the inner wall of curved duct, which phenomenon is not recognized in mild curved duct. The present method could predict such velocity profiles correctly and reproduce the separated flow generated near the outlet cross section of curved duct. Adding to this, calculated results show clearly that the generation of maximum velocity near a inner wall is caused by pressure driven secondary flow which moves to inner wall from outer wall along symmetrical axis. As for the comparison of Reynolds stresses, the present turbulent model relatively predicts the experimental data well except for the flow separated region which is located near the outlet cross section of curved duct. (author)

  19. variations in dimensions and shape of thoracic cage with aging

    African Journals Online (AJOL)

    the rib cage dimensions, the shape and cross- ..... Figure 6: CT axial section of thorax, showing the internal thoracic dimensions and shape at different age .... Dean J, Koehler R, Schleien C, Michael J, Chantarojanasiri T, Rogers M, Traystman ...

  20. Modelling foot height and foot shape-related dimensions.

    Science.gov (United States)

    Xiong, Shuping; Goonetilleke, Ravindra S; Witana, Channa P; Lee Au, Emily Yim

    2008-08-01

    The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.

  1. Accurate SHAPE-directed RNA secondary structure modeling, including pseudoknots.

    Science.gov (United States)

    Hajdin, Christine E; Bellaousov, Stanislav; Huggins, Wayne; Leonard, Christopher W; Mathews, David H; Weeks, Kevin M

    2013-04-02

    A pseudoknot forms in an RNA when nucleotides in a loop pair with a region outside the helices that close the loop. Pseudoknots occur relatively rarely in RNA but are highly overrepresented in functionally critical motifs in large catalytic RNAs, in riboswitches, and in regulatory elements of viruses. Pseudoknots are usually excluded from RNA structure prediction algorithms. When included, these pairings are difficult to model accurately, especially in large RNAs, because allowing this structure dramatically increases the number of possible incorrect folds and because it is difficult to search the fold space for an optimal structure. We have developed a concise secondary structure modeling approach that combines SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) experimental chemical probing information and a simple, but robust, energy model for the entropic cost of single pseudoknot formation. Structures are predicted with iterative refinement, using a dynamic programming algorithm. This melded experimental and thermodynamic energy function predicted the secondary structures and the pseudoknots for a set of 21 challenging RNAs of known structure ranging in size from 34 to 530 nt. On average, 93% of known base pairs were predicted, and all pseudoknots in well-folded RNAs were identified.

  2. Modeling Self-Occlusions/Disocclusions in Dynamic Shape and Appearance Tracking for Obtaining Precise Shape

    KAUST Repository

    Yang, Yanchao

    2013-01-01

    We present a method to determine the precise shape of a dynamic object from video. This problem is fundamental to computer vision, and has a number of applications, for example, 3D video/cinema post-production, activity recognition and augmented

  3. Detecting global and local hippocampal shape changes in Alzheimer's disease using statistical shape models

    NARCIS (Netherlands)

    Shen, Kai-kai; Fripp, Jurgen; Mériaudeau, Fabrice; Chételat, Gaël; Salvado, Olivier; Bourgeat, Pierrick; Saradha, A.; Abdi, Hervé; Abdulkadir, Ahmed; Acharya, Deepa; Achuthan, Anusha; Adluru, Nagesh; Aghajanian, Jania; Agrusti, Antonella; Agyemang, Alex; Ahdidan, Jamila; Ahmad, Duaa; Ahmed, Shiek; Aisen, Paul; Akhondi-Asl, Alireza; Aksu, Yaman; Alberca, Roman; Alcauter, Sarael; Alexander, Daniel; Alin, Aylin; Almeida, Fabio; Alvarez-Lineara, Juan; Amlien, Inge; Anand, Shyam; Anderson, Dallas; Ang, Amma; Angersbach, Steve; Ansarian, Reza; Aoyama, Eiji; Appannah, Arti; Arfanakis, Konstantinos; Armor, Tom; Arrighi, Michael; Arumughababu, S. Vethanayaki; Arunagiri, Vidhya; Ashe-McNalley, Cody; Ashford, Wes; Le Page, Aurelie; Avants, Brian; Aviv, Richard; Awasthi, Sukrati; Ayache, Nicholas; Chen, Wei; Richard, Edo; Schmand, Ben

    2012-01-01

    The hippocampus is affected at an early stage in the development of Alzheimer's disease (AD). With the use of structural magnetic resonance (MR) imaging, we can investigate the effect of AD on the morphology of the hippocampus. The hippocampal shape variations among a population can be usually

  4. Trial of Injected Liposomal Bupivacaine vs Bupivacaine Infusion After Surgical Stabilization of Rib Fractures

    Science.gov (United States)

    2017-10-06

    Drug Effect; Rib Fractures; Rib Trauma; Surgical Procedure, Unspecified; Pain; Catheter (Other); Nerve Pain; Local Infiltration; Anesthesia, Local; Intercostal Rib; Opioid Dependence; Chest Injury Trauma; Pneumonia

  5. Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures

    OpenAIRE

    Chapman, Brandon C.; Overbey, Douglas M.; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T.; French, Andrew; Johnson, Jeffrey L.; Burlew, Clay C.; Barnett, Carlton; Moore, Ernest E.; Pieracci, Fredric M.

    2016-01-01

    Background Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. Objectives The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Methods Retrospective coho...

  6. Rib fixation for severe chest deformity due to multiple rib fractures.

    Science.gov (United States)

    Igai, Hitoshi; Kamiyoshihara, Mitsuhiro; Nagashima, Toshiteru; Ohtaki, Yoichi

    2012-01-01

    The operative indications for rib fracture repair have been a matter of debate. However, several reports have suggested that flail chest, pain on respiration, and chest deformity/defect are potential conditions for rib fracture repair. We describe our experience of rib fixation in a patient with severe chest deformity due to multiple rib fractures. A 70-year-old woman was admitted with right-sided multiple rib fractures (2nd to 7th) and marked chest wall deformity without flailing caused by an automobile accident. Collapse of the chest wall was observed along the middle anterior axillary line. At 11 days after the injury, surgery was performed to repair the chest deformity, as it was considered to pose a risk of restrictive impairment of pulmonary function or chronic intercostal pain in the future. Operative findings revealed marked displacement of the superior 4 ribs, from the 2nd to the 5th, and collapse of the osseous chest wall towards the thoracic cavity. After exposure of the fracture regions, ribs fixations were performed using rib staplers. The total operation time was 90 minutes, and the collapsed portion of the chest wall along the middle anterior axillary line was reconstructed successfully.

  7. Beam shaping for conformal fractionated stereotactic radiotherapy: a modeling study

    International Nuclear Information System (INIS)

    Hacker, Fred L.; Kooy, Hanne M.; Bellerive, Marc R.; Killoran, Joseph H.; Leber, Zachary H.; Shrieve, Dennis C.; Tarbell, Nancy J.; Loeffler, Jay S.

    1997-01-01

    Purpose: The patient population treated with fractionated stereotactic radiotherapy (SRT) is significantly different than that treated with stereotactic radiosurgery (SRS). Generally, lesions treated with SRT are larger, less spherical, and located within critical regions of the central nervous system; hence, they offer new challenges to the treatment planner. Here a simple, cost effective, beam shaping system has been evaluated relative to both circular collimators and an ideal dynamically conforming system for effectiveness in providing conformal therapy for these lesions. Methods and Materials: We have modeled a simple system for conformal arc therapy using four independent jaws. The jaw positions and collimator angle are changed between arcs but held fixed for the duration of each arc. Eleven previously treated SRT cases have been replanned using this system. The rectangular jaw plans were then compared to the original treatment plans which used circular collimators. The plans were evaluated with respect to tissue sparing at 100%, 80%, 50%, and 20% of the prescription dose. A plan was also done for each tumor in which the beam aperture was continuously conformed to the beams eye view projection of the tumor. This was used as an ideal standard for conformal therapy in the absence of fluence modulation. Results: For tumors with a maximum extent of over 3.5 cm the rectangular jaw plans reduced the mean volume of healthy tissue involved at the prescription dose by 57% relative to the circular collimator plans. The ideal conformal plans offered no significant further improvement at the prescription dose. The relative advantage of the rectangular jaw plans decreased at lower isodoses so that at 20% of the prescription dose tissue involvement for the rectangular jaw plans was equivalent to that for the circular collimator plans. At these isodoses the ideal conformal plans gave substantially better tissue sparing. Conclusion: A simple and economical field shaping

  8. Sparse principal component analysis in medical shape modeling

    Science.gov (United States)

    Sjöstrand, Karl; Stegmann, Mikkel B.; Larsen, Rasmus

    2006-03-01

    Principal component analysis (PCA) is a widely used tool in medical image analysis for data reduction, model building, and data understanding and exploration. While PCA is a holistic approach where each new variable is a linear combination of all original variables, sparse PCA (SPCA) aims at producing easily interpreted models through sparse loadings, i.e. each new variable is a linear combination of a subset of the original variables. One of the aims of using SPCA is the possible separation of the results into isolated and easily identifiable effects. This article introduces SPCA for shape analysis in medicine. Results for three different data sets are given in relation to standard PCA and sparse PCA by simple thresholding of small loadings. Focus is on a recent algorithm for computing sparse principal components, but a review of other approaches is supplied as well. The SPCA algorithm has been implemented using Matlab and is available for download. The general behavior of the algorithm is investigated, and strengths and weaknesses are discussed. The original report on the SPCA algorithm argues that the ordering of modes is not an issue. We disagree on this point and propose several approaches to establish sensible orderings. A method that orders modes by decreasing variance and maximizes the sum of variances for all modes is presented and investigated in detail.

  9. Fatigue strength of the joint between diaphragms and longitudinal ribs in box section girders; Hako danmen keta no diaphragm to shita flange tateribu no kosabu no hiro kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Miki, C.; Shiozaki, M.; Takeishi, K. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering; Ohashi, H. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1997-04-21

    Discussions were given on crossing joints of diaphragms on hanger fixing sections and U-ribs on lower flanges in reinforcing box girders of a suspension bridge, as to their local stress generating behavior and effects of cope holes on fatigue strength. The test pieces have dimensions and shapes modeling the crossing joints, and the steel materials are SM490YA for upper and lower flanges and webs, and SS400 for U-ribs. The loading test was performed with four-point bending and at loading amplitudes of 30 to 45 tf. Furthermore, stress analysis was conducted by using the finite element method. The following conclusions were obtained as a result: local stress at cope hole tips decreases and fatigue strength increases with the smaller the cope hole diameter; when the cope holes are back-filled completely, deformation is concentrated on welds of the U-ribs and the flanges, generating high local stress; this reduces significantly the fatigue strength of details having no cope holes; and no particular differences are found on effects of boxing of the cope hole tips on the fatigue strength. 7 refs., 10 figs., 3 tabs.

  10. Isolated rib fractures in geriatric patients

    Directory of Open Access Journals (Sweden)

    Elmistekawy Elsayed

    2007-01-01

    Full Text Available Introduction: The goal of this study was to investigate the short-term outcomes in patients older than 60 years with isolated rib fractures and admitted to emergency hospital. Materials and Methods: This study included patients who were 60 years old or more and sustained blunt chest injury and had isolated rib fractures. The following data were obtained from the medical records: age, gender, number of fracture ribs, side of fracture ribs, mechanism and nature of injury, preexisting medical conditions, complications, admission to intensive care unit (ICU, need for mechanical ventilation, length of ICU and hospital stay and mortality. Results: For the study, 39 patients who were 60 years old or more and admitted to the hospital because of isolated rib fractures were enrolled. There were 28 males (71.7% and 11 females (28.3% with mean age of (66.84 ± 4.7 years. No correlation was found between comorbidities and hospital outcomes except in those who were diabetic (P-value = 0.005 and those with chronic lung disease (P-value = 0.006. Pulmonary complications were the most frequent complications encountered in those patients. Pulmonary complications were: lung contusion in 8 patients (20.5% and pulmonary infection in 6 patients (15.8%. Conclusion: Elderly patients sustaining blunt chest trauma had significant morbidity and potential for mortality.

  11. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors.

    Science.gov (United States)

    Nambu, Atsushi; Onishi, Hiroshi; Aoki, Shinichi; Tominaga, Licht; Kuriyama, Kengo; Araya, Masayuki; Saito, Ryoh; Maehata, Yoshiyasu; Komiyama, Takafumi; Marino, Kan; Koshiishi, Tsuyota; Sawada, Eiichi; Araki, Tsutomu

    2013-02-07

    As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1-10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

  12. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

    International Nuclear Information System (INIS)

    Nambu, Atsushi; Marino, Kan; Koshiishi, Tsuyota; Sawada, Eiichi; Araki, Tsutomu; Onishi, Hiroshi; Aoki, Shinichi; Tominaga, Licht; Kuriyama, Kengo; Araya, Masayuki; Saito, Ryoh; Maehata, Yoshiyasu; Komiyama, Takafumi

    2013-01-01

    As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients

  13. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

    Directory of Open Access Journals (Sweden)

    Nambu Atsushi

    2013-02-01

    Full Text Available Abstract Background As stereotactic body radiotherapy (SBRT is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Methods Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT. The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED was calculated with a range of α/β ratios (1–10 Gy. Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Results Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41, and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Conclusions Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

  14. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

    Science.gov (United States)

    2013-01-01

    Background As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Methods Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Results Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Conclusions Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients. PMID:23391264

  15. Chondroblastoma of rib in situs inversus

    Directory of Open Access Journals (Sweden)

    Purwa R Patil

    2014-01-01

    Full Text Available Chondroblastoma is a rare benign cartilaginous tumour accounting for approximately 1% of all bone tumours. It commonly arises from epiphysis of a long bone, particularly the humerus, tibia and femur. Rib is an extremely rare site for this tumour with a few cases reported in the literature. It is commonly seen in children and adults between the ages of 10 - 20 years. Although roentgenographic findings are quite common characteristic of this tumour, it can sometimes be misdiagnosed as giant cell tumour, osteogenic sarcoma and myeloma on histopathology. We report a 26-year-old male patient with situs inversus and chondroblastoma of rib. To the best of our knowledge, this is the first case of chondroblastoma of the rib in a patient of situs inversus. Segmental resection is the treatment of choice. It usually behaves in a benign fashion, but few cases have shown local recurrences and distant metastasis; hence, follow-up of the patient is essential.

  16. Recent Progress on Modeling Slip Deformation in Shape Memory Alloys

    Science.gov (United States)

    Sehitoglu, H.; Alkan, S.

    2018-03-01

    This paper presents an overview of slip deformation in shape memory alloys. The performance of shape memory alloys depends on their slip resistance often quantified through the Critical Resolved Shear Stress (CRSS) or the flow stress. We highlight previous studies that identify the active slip systems and then proceed to show how non- Schmid effects can be dominant in shape memory slip behavior. The work is mostly derived from our recent studies while we highlight key earlier works on slip deformation. We finally discuss the implications of understanding the role of slip on curtailing the transformation strains and also the temperature range over which superelasticity prevails.

  17. Recent Progress on Modeling Slip Deformation in Shape Memory Alloys

    Science.gov (United States)

    Sehitoglu, H.; Alkan, S.

    2018-03-01

    This paper presents an overview of slip deformation in shape memory alloys. The performance of shape memory alloys depends on their slip resistance often quantified through the Critical Resolved Shear Stress (CRSS) or the flow stress. We highlight previous studies that identify the active slip systems and then proceed to show how non-Schmid effects can be dominant in shape memory slip behavior. The work is mostly derived from our recent studies while we highlight key earlier works on slip deformation. We finally discuss the implications of understanding the role of slip on curtailing the transformation strains and also the temperature range over which superelasticity prevails.

  18. A probabilistic model for component-based shape synthesis

    KAUST Repository

    Kalogerakis, Evangelos; Chaudhuri, Siddhartha; Koller, Daphne; Koltun, Vladlen

    2012-01-01

    represents probabilistic relationships between properties of shape components, and relates them to learned underlying causes of structural variability within the domain. These causes are treated as latent variables, leading to a compact representation

  19. Modeling of hydrogen Stark line shapes with kinetic theory methods

    Science.gov (United States)

    Rosato, J.; Capes, H.; Stamm, R.

    2012-12-01

    The unified formalism for Stark line shapes is revisited and extended to non-binary interactions between an emitter and the surrounding perturbers. The accuracy of this theory is examined through comparisons with ab initio numerical simulations.

  20. Morbidity, mortality, associated injuries, and management of traumatic rib fractures

    Directory of Open Access Journals (Sweden)

    Frank Cheau-Feng Lin

    2016-06-01

    Conclusion: The severity of traumatic rib fractures was identified in this study. Therefore, a trauma team needs better preparation to provide effective treatment strategies when encountering thoracic trauma patients, especially patients who are older and have rib fractures.

  1. Post-accelerator LINAC design for the VECC RIB project

    Indian Academy of Sciences (India)

    acclerator type of RIB facility. The scheme utilises the existing = 130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency quadrupole (RFQ) and LINAC modules for ...

  2. Modeling of mechanical properties for ferrous shape memory alloy

    International Nuclear Information System (INIS)

    Wada, Manabu; Ide, Yusuke; Mizote, Shinichiro; Naoi, Hisashi; Tsukimori, Kazuyuki

    2002-08-01

    In order to acquire technical data that are necessary for manufacture and design of the simulation test device for analyzing the core mechanics of Fast Breeder Reactor, ferrous shape memory alloy of Fe-28%Mn-6%Si-5%Cr is melted, forged and heat-treated. The microstructures are austenite. The specimens are deformed of up to 16% work-strain by tensile and compressive test, resulting in appearance of epsilon-martensite that is induced by stress. Then, heating at 673K for 10 minutes causes austenitic transformation from epsilon-martensite and shape memory strains are measured. We also investigate shape memory character of specimens, which are given, so called 'training treatment' of 5% pre-strain and recovery heat treatment. As a result, there is little difference between tensile and compressive test without training treatment and shape memory strain is 2% after being given 5% work-strain and recovery heat treatment. On the other hand, training treatment is remarkable and shape memory strain reaches to 3.7% after 5% work-strain. We analyze shape recovery character of this alloy specimen at three-point bending by using finite element method, and indicate possibility that its deformation behavior can be estimated from mechanical properties' data obtained at tensile and compressive test. (author)

  3. Rib fractures and their association With solid organ injury: higher rib fractures have greater significance for solid organ injury screening.

    Science.gov (United States)

    Rostas, Jack W; Lively, Timothy B; Brevard, Sidney B; Simmons, Jon D; Frotan, Mohammad A; Gonzalez, Richard P

    2017-04-01

    The purpose of this study was to identify patients with rib injuries who were at risk for solid organ injury. A retrospective chart review was performed of all blunt trauma patients with rib fractures during the period from July 2007 to July 2012. Data were analyzed for association of rib fractures and solid organ injury. In all, 1,103 rib fracture patients were identified; 142 patients had liver injuries with 109 (77%) associated right rib fractures. Right-sided rib fractures with highest sensitivity for liver injury were middle rib segment (5 to 8) and lower segment (9 to 12) with liver injury sensitivities of 68% and 43%, respectively (P rib fractures. Left middle segment rib fractures and lower segment rib fractures had sensitivities of 80% and 63% for splenic injury, respectively (P Rib fractures higher in the thoracic cage have significant association with solid organ injury. Using rib fractures from middle plus lower segments as indication for abdominal screening will significantly improve rib fracture sensitivity for identification of solid organ injury. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Feature extraction for face recognition via Active Shape Model (ASM) and Active Appearance Model (AAM)

    Science.gov (United States)

    Iqtait, M.; Mohamad, F. S.; Mamat, M.

    2018-03-01

    Biometric is a pattern recognition system which is used for automatic recognition of persons based on characteristics and features of an individual. Face recognition with high recognition rate is still a challenging task and usually accomplished in three phases consisting of face detection, feature extraction, and expression classification. Precise and strong location of trait point is a complicated and difficult issue in face recognition. Cootes proposed a Multi Resolution Active Shape Models (ASM) algorithm, which could extract specified shape accurately and efficiently. Furthermore, as the improvement of ASM, Active Appearance Models algorithm (AAM) is proposed to extracts both shape and texture of specified object simultaneously. In this paper we give more details about the two algorithms and give the results of experiments, testing their performance on one dataset of faces. We found that the ASM is faster and gains more accurate trait point location than the AAM, but the AAM gains a better match to the texture.

  5. RibM from Streptomyces davawensis is a riboflavin/roseoflavin transporter and may be useful for the optimization of riboflavin production strains

    Science.gov (United States)

    2011-01-01

    Background The bacterium Bacillus subtilis, which is not a natural riboflavin overproducer, has been converted into an excellent production strain by classical mutagenesis and metabolic engineering. To our knowledge, the enhancement of riboflavin excretion from the cytoplasm of overproducing cells has not yet been considered as a target for (further) strain improvement. Here we evaluate the flavin transporter RibM from Streptomyces davawensis with respect to improvement of a riboflavin production strain. Results The gene ribM from S. davawensis, coding for a putative facilitator of riboflavin uptake, was codon optimized (ribMopt) for expression in B. subtilis. The gene ribMopt was functionally introduced into B. subtilis using the isopropyl-β-thiogalactopyranoside (IPTG)-inducible expression plasmid pHT01: Northern-blot analysis of total RNA from IPTG treated recombinant B. subtilis cells revealed a ribMopt specific transcript. Western blot analysis showed that the his6-tagged heterologous gene product RibM was present in the cytoplasmic membrane. Expression of ribM in Escherichia coli increased [14C]riboflavin uptake, which was not affected by the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP). Expression of ribMopt supported growth of a B. subtilis ΔribB::Ermr ΔribU::Kanr double mutant deficient in riboflavin synthesis (ΔribB) and also deficient with respect to riboflavin uptake (ΔribU). Expression of ribMopt increased roseoflavin (a toxic riboflavin analog produced by S. davawensis) sensitivity of a B. subtilis ΔribU::Kanr strain. Riboflavin synthesis by a model riboflavin B. subtilis production strain overproducing RibM was increased significantly depending on the amount of the inducer IPTG. Conclusions The energy independent flavin facilitator RibM could in principle catalyze riboflavin export and thus may be useful to increase the riboflavin yield in a riboflavin production process using a recombinant RibM overproducing B. subtilis strain

  6. Ultrasound Common Carotid Artery Segmentation Based on Active Shape Model

    Science.gov (United States)

    Yang, Xin; Jin, Jiaoying; Xu, Mengling; Wu, Huihui; He, Wanji; Yuchi, Ming; Ding, Mingyue

    2013-01-01

    Carotid atherosclerosis is a major reason of stroke, a leading cause of death and disability. In this paper, a segmentation method based on Active Shape Model (ASM) is developed and evaluated to outline common carotid artery (CCA) for carotid atherosclerosis computer-aided evaluation and diagnosis. The proposed method is used to segment both media-adventitia-boundary (MAB) and lumen-intima-boundary (LIB) on transverse views slices from three-dimensional ultrasound (3D US) images. The data set consists of sixty-eight, 17 × 2 × 2, 3D US volume data acquired from the left and right carotid arteries of seventeen patients (eight treated with 80 mg atorvastatin and nine with placebo), who had carotid stenosis of 60% or more, at baseline and after three months of treatment. Manually outlined boundaries by expert are adopted as the ground truth for evaluation. For the MAB and LIB segmentations, respectively, the algorithm yielded Dice Similarity Coefficient (DSC) of 94.4% ± 3.2% and 92.8% ± 3.3%, mean absolute distances (MAD) of 0.26 ± 0.18 mm and 0.33 ± 0.21 mm, and maximum absolute distances (MAXD) of 0.75 ± 0.46 mm and 0.84 ± 0.39 mm. It took 4.3 ± 0.5 mins to segment single 3D US images, while it took 11.7 ± 1.2 mins for manual segmentation. The method would promote the translation of carotid 3D US to clinical care for the monitoring of the atherosclerotic disease progression and regression. PMID:23533535

  7. Ultrasound Common Carotid Artery Segmentation Based on Active Shape Model

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2013-01-01

    Full Text Available Carotid atherosclerosis is a major reason of stroke, a leading cause of death and disability. In this paper, a segmentation method based on Active Shape Model (ASM is developed and evaluated to outline common carotid artery (CCA for carotid atherosclerosis computer-aided evaluation and diagnosis. The proposed method is used to segment both media-adventitia-boundary (MAB and lumen-intima-boundary (LIB on transverse views slices from three-dimensional ultrasound (3D US images. The data set consists of sixty-eight, 17 × 2 × 2, 3D US volume data acquired from the left and right carotid arteries of seventeen patients (eight treated with 80 mg atorvastatin and nine with placebo, who had carotid stenosis of 60% or more, at baseline and after three months of treatment. Manually outlined boundaries by expert are adopted as the ground truth for evaluation. For the MAB and LIB segmentations, respectively, the algorithm yielded Dice Similarity Coefficient (DSC of 94.4% ± 3.2% and 92.8% ± 3.3%, mean absolute distances (MAD of 0.26 ± 0.18 mm and 0.33 ± 0.21 mm, and maximum absolute distances (MAXD of 0.75 ± 0.46 mm and 0.84 ± 0.39 mm. It took 4.3 ± 0.5 mins to segment single 3D US images, while it took 11.7 ± 1.2 mins for manual segmentation. The method would promote the translation of carotid 3D US to clinical care for the monitoring of the atherosclerotic disease progression and regression.

  8. Comparison of ultrasonography and radiography in diagnosis of rib fractures

    OpenAIRE

    Pishbin, Elham; Ahmadi, Koorosh; Foogardi, Molood; Salehi, Maryam; Seilanian Toosi, Farrokh; Rahimi-Movaghar, Vafa

    2017-01-01

    Purpose: Rib fractures are the most common skeletal thoracic injuries resulting from blunt chest trauma. Half of the rib fractures are not detected upon a precise physical evaluation and radiographs. Recently ultrasonography (USG) has been investigated to detect rib fractures. But based on literature the usefulness of USG varies widely. This study was conducted to investigate the role of USG in the detection of possible rib fractures in comparison with radiography. Methods: In this cross-s...

  9. Anatomically contoured plates for fixation of rib fractures.

    Science.gov (United States)

    Bottlang, Michael; Helzel, Inga; Long, William B; Madey, Steven

    2010-03-01

    : Intraoperative contouring of long bridging plates for stabilization of flail chest injuries is difficult and time consuming. This study implemented for the first time biometric parameters to derive anatomically contoured rib plates. These plates were tested on a range of cadaveric ribs to quantify plate fit and to extract a best-fit plating configuration. : Three left and three right rib plates were designed, which accounted for anatomic parameters required when conforming a plate to the rib surface. The length lP over which each plate could trace the rib surface was evaluated on 109 cadaveric ribs. For each rib level 3-9, the plate design with the highest lP value was extracted to determine a best-fit plating configuration. Furthermore, the characteristic twist of rib surfaces was measured on 49 ribs to determine the surface congruency of anatomic plates with a constant twist. : The tracing length lP of the best-fit plating configuration ranged from 12.5 cm to 14.7 cm for ribs 3-9. The corresponding range for standard plates was 7.1-13.7 cm. The average twist of ribs over 8-cm, 12-cm, and 16-cm segments was 8.3 degrees, 20.6 degrees, and 32.7 degrees, respectively. The constant twist of anatomic rib plates was not significantly different from the average rib twist. : A small set of anatomic rib plates can minimize the need for intraoperative plate contouring for fixation of ribs 3-9. Anatomic rib plates can therefore reduce the time and complexity of flail chest stabilization and facilitate spanning of flail segments with long plates.

  10. Estimation of carcass composition using rib dissection of calf-fed Holstein steers supplemented zilpaterol hydrochloride.

    Science.gov (United States)

    McEvers, T J; May, N D; Reed, J A; Walter, L J; Hutcheson, J P; Lawrence, T E

    2018-04-14

    A serial harvest was conducted every 28 d from 254 to 534 d on feed (DOF) to quantify changes in growth and composition of calf-fed Holstein steers (n = 115, initial body weight (BW) = 449.2 ± 19.9 kg). One-half were supplemented with the β-2 adrenergic agonist zilpaterol hydrochloride (ZH; 8.33 mg/kg 100% dry matter (DM) basis) during the final 20 d followed by a 3-d withdrawal prior to harvest; the remainder was fed a non-ZH control (CON) ration. Five steers were randomly selected and harvested after 226 DOF which served as a reference point for modeling purposes. Fabricated carcass soft tissue was ground, mixed, and subsampled for proximate analysis. Moreover, following the traditional method of rib dissection which includes the 9th, 10th, and 11th rib contained within the IMPS 103 primal, the relationship of carcass chemical composition to 9-10-11 rib composition was evaluated. Carcasses in this investigation had more (P carcasses and rib dissections. Using regression procedures, models were constructed to describe the relationship of rib dissection (RD) composition including separable lean (RDSL), separable fat (RDSF), separable bone (RDSB), ether extract (RDEE), protein (RDP), moisture (RDM), and ash (RDA) with carcass composition. Carcass lean (CL), carcass fat (CF), and carcass bone (CB) were correlated (P carcass, carcass ether extract (CEE), carcass protein (CP), carcass moisture (CM), and carcass ash (CA) were correlated (P ≤ 0.01) with simple r values of 0.75, 0.31, 0.66, and 0.37, respectively. Equations to predict carcass fatness from rib dissection variables and ZH supplementation status were only able to account for 50 and 56%, of the variability of CF and CEE, respectively. Overall, the relationships quantified and equations developed in this investigation do not support use of 9/10/11 rib dissection for estimation of carcass composition of calf-fed Holstein steers.

  11. Optimization of ultrasonic array inspections using an efficient hybrid model and real crack shapes

    Energy Technology Data Exchange (ETDEWEB)

    Felice, Maria V., E-mail: maria.felice@bristol.ac.uk [Department of Mechanical Engineering, University of Bristol, Bristol, U.K. and NDE Laboratory, Rolls-Royce plc., Bristol (United Kingdom); Velichko, Alexander, E-mail: p.wilcox@bristol.ac.uk; Wilcox, Paul D., E-mail: p.wilcox@bristol.ac.uk [Department of Mechanical Engineering, University of Bristol, Bristol (United Kingdom); Barden, Tim; Dunhill, Tony [NDE Laboratory, Rolls-Royce plc., Bristol (United Kingdom)

    2015-03-31

    Models which simulate the interaction of ultrasound with cracks can be used to optimize ultrasonic array inspections, but this approach can be time-consuming. To overcome this issue an efficient hybrid model is implemented which includes a finite element method that requires only a single layer of elements around the crack shape. Scattering Matrices are used to capture the scattering behavior of the individual cracks and a discussion on the angular degrees of freedom of elastodynamic scatterers is included. Real crack shapes are obtained from X-ray Computed Tomography images of cracked parts and these shapes are inputted into the hybrid model. The effect of using real crack shapes instead of straight notch shapes is demonstrated. An array optimization methodology which incorporates the hybrid model, an approximate single-scattering relative noise model and the real crack shapes is then described.

  12. General correlations for pressure drop and heat transfer for single-phase turbulent flow in internally ribbed tubes

    International Nuclear Information System (INIS)

    Ravigururajan, T.S.; Bergles, A.E.

    1985-01-01

    General correlations for friction factors and heat transfer coefficients for single-phase turbulent flow in internally ribbed tubes are presented. Data from previous investigations are gathered for a wide range of tube parameters with e/d: 0.01 to 0.2; p/d: 0.1 to 7.0; α/90: 0.3 to 1.0, and flow parameters Re: 5000 to 250,000 and Pr: 0.66 to 37.6. The data were applied to a linear model to get normalized correlations that were then modified to fit tubes with extremely small parametric values. A shape function was included in the friction correlation to account for different rib profiles. The friction correlation predicts 96% of the data base to within +. 50% and 77% of the data base to within +. 20%. Corresponding figures for the heat transfer correlation are 99% and 69%. The present correlations are superior, for this extensive data base, to those presented by other investigators

  13. AUGMENTATION OF RIBS TURBULATORS HEIGHT ON THE HYDROTHERMAL PERFORMANCE OF DOUBLE PIPE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    HUSSAIN H. AL-KAYIEM

    2017-02-01

    Full Text Available Thermal performance of double pipe heat exchanger can be enhanced by imposed turbulence in the annular flow using artificial roughening. This paper presents experimental results on enhancing the heat transfer by artificial roughening using energy promoters installed on the inner surface of the cold flow annulus. An experimental test rig was fabricated having 2.0 m long annular flow test section with 76.2 mm and 34.2 mm outside and inside diameters, respectively. The energy promoters have ribs shape with rectangular cross section. Two cases of rib’s pitch to height ratios, equal to 10 and 15 and three height to hydraulic diameter, equal to 0.0595, 0.083, and 0.107 have been studied. The investigations were carried out at various flow rates within Reynolds number range of 2900 to 21000 in the cold annulus. For each roughening case, the thermal and hydraulic performances wereevaluated by determining Stanton number and the associated pressure drop, respectively. The experimental results showed that enhancement in the heat transfer was combined with a penalty in the pressure drop due to the increase in the friction factor values. The combined hydrothermal enhancement results of the DPHE, in terms of the performance index, indicate that the small height ribs to hydraulic diameter of 0.0595, augmented higher than the large height ribs to hydraulic diameter of 0.107. Hence, it is recommended to use ribs installed on the inner surface of the annulus ribs to hydraulic diameter in the range of 0.06 ± 0.005. Also, it is recommended to investigate further parameters to explore further on the influencing of the ribs on the hydrothermal performance of the DPHE.

  14. Influence of mesh density, cortical thickness and material properties on human rib fracture prediction.

    Science.gov (United States)

    Li, Zuoping; Kindig, Matthew W; Subit, Damien; Kent, Richard W

    2010-11-01

    The purpose of this paper was to investigate the sensitivity of the structural responses and bone fractures of the ribs to mesh density, cortical thickness, and material properties so as to provide guidelines for the development of finite element (FE) thorax models used in impact biomechanics. Subject-specific FE models of the second, fourth, sixth and tenth ribs were developed to reproduce dynamic failure experiments. Sensitivity studies were then conducted to quantify the effects of variations in mesh density, cortical thickness, and material parameters on the model-predicted reaction force-displacement relationship, cortical strains, and bone fracture locations for all four ribs. Overall, it was demonstrated that rib FE models consisting of 2000-3000 trabecular hexahedral elements (weighted element length 2-3mm) and associated quadrilateral cortical shell elements with variable thickness more closely predicted the rib structural responses and bone fracture force-failure displacement relationships observed in the experiments (except the fracture locations), compared to models with constant cortical thickness. Further increases in mesh density increased computational cost but did not markedly improve model predictions. A ±30% change in the major material parameters of cortical bone lead to a -16.7 to 33.3% change in fracture displacement and -22.5 to +19.1% change in the fracture force. The results in this study suggest that human rib structural responses can be modeled in an accurate and computationally efficient way using (a) a coarse mesh of 2000-3000 solid elements, (b) cortical shells elements with variable thickness distribution and (c) a rate-dependent elastic-plastic material model. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  15. Sand transport in a two pass internal cooling duct with rib turbulators

    International Nuclear Information System (INIS)

    Singh, Sukhjinder; Tafti, Danesh; Reagle, Colin; Delimont, Jacob; Ng, Wing; Ekkad, Srinath

    2014-01-01

    Highlights: • Highest particle impingement observed in the bend and first quarter of 2nd pass. • Average particle impingement per pitch is 28% higher in the second pass. • Rib faces are by far the most susceptible to particle impingement. • Particle impingement is sensitive to particle size. • Particle impingement is sensitive to wall collision model used. - Abstract: Jet engines often operate under dirty conditions where large amounts of particulate matter can be ingested, especially, sand, ash and dirt. Particulate matter in different engine components can lead to degradation in performance. The focus of this study is to investigate the sand transport and deposition in the internal cooling passages of turbine blades. A two pass stationary square duct with rib turbulators subjected to sand ingestion is studied using Large Eddy Simulations (LES). Each pass has ribs on two opposite walls and aligned normal to the main flow direction. The rib pitch to rib height (P/e) is 9.28, the rib height to channel hydraulic diameter (e/D h ) is 0.0625 and calculations have been carried out for a bulk Reynolds number of 25,000. Particle sizes in the range 0.5–25 μm are considered, with the same size distribution as found in Arizona Road Dust (medium). Large Eddy Simulation (LES) with a wall-model is used to model the flow and sand particles are modeled using a discrete Lagrangian framework. Results quantify the distribution of particle impingement density on all surfaces. Highest particle impingement density is found in the first quarter section of the second pass after the 180° turn, where the recorded impingement is more than twice that of any other region. It is also found that the average particle impingement per pitch is 28% higher in the second pass than the first pass. Results show lower particle tendency to impact the region immediately behind the rib in the first pass compared to the second pass where particle impingement is more uniform in the region

  16. First Rib Fracture Resulting in Horner's Syndrome.

    Science.gov (United States)

    Lin, You-Cheng; Chuang, Ming-Tsung; Hsu, Chin-Hao; Tailor, Al-Rahim Abbasali; Lee, Jung-Shun

    2015-12-01

    First rib fractures and traumatic Horner's syndrome are both quite rare, which can make it difficult to properly diagnose the combination of these 2 conditions in the emergency department. These conditions may be associated with severe medical emergencies, such as ongoing carotid dissection. We present the case of a 33-year-old man who sustained fractures to his right second, third, and fourth ribs and a delay in the diagnosis of left Horner's syndrome after he was involved in a traffic accident. Left Horner's syndrome was caused by a left transverse fracture of the first rib. This fracture was not detected on chest radiographs and required a 3-dimensional reconstructed neck computed tomography scan for detection. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: In the diagnosis of carotid artery dissection, conventional angiography is the criterion standard but is considered invasive. CTA is less invasive, time-saving, and can show more anatomic structures in the neck in addition to the carotid arteries. It is a good screening diagnostic modality in the traumatology department. Although the treatments for Horner's syndrome and first rib fracture are conservative, the early diagnosis of both conditions can resolve the anxiety and uncertainty experienced by both doctors and patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. [Internal fixation treatment of multiple rib fractures with absorbable rib-connecting-pins].

    Science.gov (United States)

    Liu, Jinliang; Li, Keyao; He, Jianning

    2011-01-01

    To study the indications, methods, and therapeutic effect of absorbable rib-connecting-pins fixation in the treatment of multiple rib fractures. Between March 2007 and September 2009, 40 patients with multiple rib fractures received internal fixation with absorbable rib-connecting-pins, including 8 one-side flail chest and 1 two-side flail chest. There were 32 males and 8 females with an average age of 39.8 years (range, 25-72 years). The injury was caused by traffic accident in 32 cases, falling from height in 6 cases, and blunt hitting in 2 cases. Preoperatively, imaging data of the chest X-ray or spiral CT three-dimensional (3D) examination showed that all patients had multiple ribs fractures and displacement. The number of fractured ribs was 4-10 (median, 6), and the fracture location ranged from the 2nd to the 10th ribs. Of them, 28 cases were accompanied by hemathorax, pneumothorax or hemopneumothorax; 5 cases by thoracic organ injury; and 10 cases by other part trauma. The time from injury to hospitalization was less than 1 day in 26 cases, 1-3 days in 12 cases, and 3-6 days in 2 cases, and the time from hospitalization to operation was 3 hours to 3 days (mean, 1.2 days). The median fixation rib number was 5 (range, 3-8). The mean operative time, the time in bed, and hospitalization days were 32 minutes (range, 15-50 minutes), 4.5 days (range, 2-7 days), and 11.2 days (range, 5-18 days), respectively. All incisions healed by first intention. No pulmonary infection, pulmonary atelectasis, intrathoracic infection or other complications occurred. All cases were followed up 6-12 months (mean, 8 months). PaO2 [(86.6 +/- 2.2) mmHg (1 mm Hg = 0.133 kPa)] and SpO2 (97.2% +/- 0.6%) at 2 hours after operation were obviously improved when compared with preoperative ones (PaO2 (53.6 + 4.7) mm Hg and SpO2 (86.2% + 1.8%)], showing significant differences (t = 2.971, P = 0.005; t = 2.426, P = 0.020). The chest X-ray films or spiral CT 3D indicated that fracture of rib

  18. Quantitative Outline-based Shape Analysis and Classification of Planetary Craterforms using Supervised Learning Models

    Science.gov (United States)

    Slezak, Thomas Joseph; Radebaugh, Jani; Christiansen, Eric

    2017-10-01

    The shapes of craterform morphology on planetary surfaces provides rich information about their origins and evolution. While morphologic information provides rich visual clues to geologic processes and properties, the ability to quantitatively communicate this information is less easily accomplished. This study examines the morphology of craterforms using the quantitative outline-based shape methods of geometric morphometrics, commonly used in biology and paleontology. We examine and compare landforms on planetary surfaces using shape, a property of morphology that is invariant to translation, rotation, and size. We quantify the shapes of paterae on Io, martian calderas, terrestrial basaltic shield calderas, terrestrial ash-flow calderas, and lunar impact craters using elliptic Fourier analysis (EFA) and the Zahn and Roskies (Z-R) shape function, or tangent angle approach to produce multivariate shape descriptors. These shape descriptors are subjected to multivariate statistical analysis including canonical variate analysis (CVA), a multiple-comparison variant of discriminant analysis, to investigate the link between craterform shape and classification. Paterae on Io are most similar in shape to terrestrial ash-flow calderas and the shapes of terrestrial basaltic shield volcanoes are most similar to martian calderas. The shapes of lunar impact craters, including simple, transitional, and complex morphology, are classified with a 100% rate of success in all models. Multiple CVA models effectively predict and classify different craterforms using shape-based identification and demonstrate significant potential for use in the analysis of planetary surfaces.

  19. Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures.

    Science.gov (United States)

    Chapman, Brandon C; Overbey, Douglas M; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T; French, Andrew; Johnson, Jeffrey L; Burlew, Clay C; Barnett, Carlton; Moore, Ernest E; Pieracci, Fredric M

    2016-12-01

    Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Retrospective cohort study of blunt trauma patients with rib fractures at a level I trauma center that had both a CXR and a CT chest. The CT finding of ≥ 3 additional fractures in patients with ≤ 3 rib fractures on CXR was considered clinically meaningful. Student's t-test and chi-square analysis were used for comparison. We identified 499 patients with rib fractures: 93 (18.6%) had CXR only, 7 (1.4%) had chest CT only, and 399 (79.9%) had both CXR and chest CT. Among these 399 patients, a total of 1,969 rib fractures were identified: 1,467 (74.5%) were missed by CXR. The median number of additional fractures identified by CT was 3 (range, 4 - 15). Of 212 (53.1%) patients with a clinically meaningful increase in the number of fractures, 68 patients underwent one or more clinical interventions: 36 SICU admissions, 20 pain catheter placements, 23 epidural placements, and 3 SSRF. Additionally, 70 patients had a chest tube placed for retained hemothorax or occult pneumothorax. Overall, 138 patients (34.5%) had a change in clinical management based upon CT chest. The chest X-ray missed ~75% of rib fractures seen on chest CT. Although patients with a clinical meaningful increase in the number of rib fractures were more likely to be admitted to the intensive care unit, there was no associated improvement in pulmonary outcomes.

  20. Non-linear scaling of a musculoskeletal model of the lower limb using statistical shape models.

    Science.gov (United States)

    Nolte, Daniel; Tsang, Chui Kit; Zhang, Kai Yu; Ding, Ziyun; Kedgley, Angela E; Bull, Anthony M J

    2016-10-03

    Accurate muscle geometry for musculoskeletal models is important to enable accurate subject-specific simulations. Commonly, linear scaling is used to obtain individualised muscle geometry. More advanced methods include non-linear scaling using segmented bone surfaces and manual or semi-automatic digitisation of muscle paths from medical images. In this study, a new scaling method combining non-linear scaling with reconstructions of bone surfaces using statistical shape modelling is presented. Statistical Shape Models (SSMs) of femur and tibia/fibula were used to reconstruct bone surfaces of nine subjects. Reference models were created by morphing manually digitised muscle paths to mean shapes of the SSMs using non-linear transformations and inter-subject variability was calculated. Subject-specific models of muscle attachment and via points were created from three reference models. The accuracy was evaluated by calculating the differences between the scaled and manually digitised models. The points defining the muscle paths showed large inter-subject variability at the thigh and shank - up to 26mm; this was found to limit the accuracy of all studied scaling methods. Errors for the subject-specific muscle point reconstructions of the thigh could be decreased by 9% to 20% by using the non-linear scaling compared to a typical linear scaling method. We conclude that the proposed non-linear scaling method is more accurate than linear scaling methods. Thus, when combined with the ability to reconstruct bone surfaces from incomplete or scattered geometry data using statistical shape models our proposed method is an alternative to linear scaling methods. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

  1. 4D Shape-Preserving Modelling of Bone Growth

    DEFF Research Database (Denmark)

    Andresen, Per Rønsholt; Nielsen, Mads; Kreiborg, Sven

    1998-01-01

    From a set of temporally separated scannings of the same anatomical structure we wish to identify and analyze the growth in terms of a metamorphosis. That is, we study the tempral change of shape which may prowide an understanding of the biological processes which govern the growth process. We...

  2. Markov Random Field Restoration of Point Correspondences for Active Shape Modelling

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Paulsen, Rasmus Reinhold; Larsen, Rasmus

    2004-01-01

    In this paper it is described how to build a statistical shape model using a training set with a sparse of landmarks. A well defined model mesh is selected and fitted to all shapes in the training set using thin plate spline warping. This is followed by a projection of the points of the warped...

  3. Blunt liver injury with intact ribs under impacts on the abdomen: a biomechanical investigation.

    Directory of Open Access Journals (Sweden)

    Yu Shao

    Full Text Available Abdominal trauma accounts for nearly 20% of all severe traffic injuries and can often result from intentional physical violence, from which blunt liver injury is regarded as the most common result and is associated with a high mortality rate. Liver injury may be caused by a direct impact with a certain velocity and energy on the abdomen, which may result in a lacerated liver by penetration of fractured ribs. However, liver ruptures without rib cage fractures were found in autopsies in a series of cases. All the victims sustained punches on the abdomen by fist. Many studies have been dedicated to determining the mechanism underlying hepatic injury following abdominal trauma, but most have been empirical. The actual process and biomechanism of liver injury induced by blunt impact on the abdomen, especially with intact ribs remained, are still inexhaustive. In order to investigate this, finite element methods and numerical simulation technology were used. A finite element human torso model was developed from high resolution CT data. The model consists of geometrically-detailed liver and rib cage models and simplified models of soft tissues, thoracic and abdominal organs. Then, the torso model was used in simulations in which the right hypochondrium was punched by a fist from the frontal, lateral, and rear directions, and in each direction with several impact velocities. Overall, the results showed that liver rupture was primarily caused by a direct strike of the ribs induced by blunt impact to the abdomen. Among three impact directions, a lateral impact was most likely to cause liver injury with a minimum punch speed of 5 m/s (the momentum was about 2.447 kg.m/s. Liver injuries could occur in isolation and were not accompanied by rib fractures due to different material characteristics and injury tolerance.

  4. Traumatic Rib Injury: Patterns, Imaging Pitfalls, Complications, and Treatment.

    Science.gov (United States)

    Talbot, Brett S; Gange, Christopher P; Chaturvedi, Apeksha; Klionsky, Nina; Hobbs, Susan K; Chaturvedi, Abhishek

    2017-01-01

    The ribs are frequently affected by blunt or penetrating injury to the thorax. In the emergency department setting, it is vital for the interpreting radiologist to not only identify the presence of rib injuries but also alert the clinician about organ-specific injury, specific traumatic patterns, and acute rib trauma complications that require emergent attention. Rib injuries can be separated into specific morphologic fracture patterns that include stress, buckle, nondisplaced, displaced, segmental, and pathologic fractures. Specific attention is also required for flail chest and for fractures due to pediatric nonaccidental trauma. Rib fractures are associated with significant morbidity and mortality, both of which increase as the number of fractured ribs increases. Key complications associated with rib fracture include pain, hemothorax, pneumothorax, extrapleural hematoma, pulmonary contusion, pulmonary laceration, acute vascular injury, and abdominal solid-organ injury. Congenital anomalies, including supernumerary or accessory ribs, vestigial anterior ribs, bifid ribs, and synostoses, are common and should not be confused with traumatic pathologic conditions. Nontraumatic mimics of traumatic rib injury, with or without fracture, include metastatic disease, primary osseous neoplasms (osteosarcoma, chondrosarcoma, Ewing sarcoma, Langerhans cell histiocytosis, and osteochondroma), fibrous dysplasia, and Paget disease. Principles of management include supportive and procedural methods of alleviating pain, treating complications, and stabilizing posttraumatic deformity. By recognizing and accurately reporting the imaging findings, the radiologist will add value to the care of patients with thoracic trauma. Online supplemental material is available for this article. © RSNA, 2017.

  5. Factors affecting visualization of posterior rib fractures in abused infants

    International Nuclear Information System (INIS)

    Kleinman, P.K.; Adams, V.I.; Blackbourne, B.D.; Marks, S.C.

    1987-01-01

    Rib fractures in abused infants commonly occur in the posterior rib arcs. Fractures occurring near the costovertebral articulations are usually identified radiographically only once callus has formed. To assess the factors influencing the visibility of fractures near the costovertical articulations, the authors studied 103 posterior rib fractures occurring in 16 abused infants. Radiologic findings were correlated with CT findings and pathologic material from nine ribs in four patients. The limited visibility of fractures relates to (1) the frequent superimposition of the transverse process over the rib fracture site, (2) a fracture line that crosses at an obliquity to the x-ray beam, and (3) nondisplacement of rib fragments due to preservation of the posterior periosteum. Fresh rib fractures invisible on a frontal projection may be clearly defined on axial CT scans, or on postmortem radiographs. A knowledge of the factors influencing the visibility of these important injuries is useful in planning an appropriate diagnostic evaluation of suspected infant abuse

  6. The contribution of rib fractures to chronic pain and disability.

    Science.gov (United States)

    Gordy, Stephanie; Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

    2014-05-01

    The contribution of rib fractures to chronic pain and disability is not well described. Two hundred three patients with rib fractures were followed for 6 months. Chronic pain was assessed using the McGill Pain Questionnaire Pain Rating Index and Present Pain Intensity (PPI) scales. Disability was defined as a decrease in work or functional status. The prevalence of chronic pain was 22% and disability was 53%. Acute PPI predicted chronic pain. Associated injuries, bilateral rib fractures, injury severity score, and number of rib fractures were not predictive of chronic pain. No acute injury characteristics were predictive of disability. Among 89 patients with isolated rib fractures, the prevalence of chronic pain was 28% and of disability was 40%. No injury characteristics predicted chronic pain. Bilateral rib fractures and acute PPI predicted disability. The contribution of rib fractures to chronic pain and disability is significant but unpredictable with conventional injury descriptors. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1)

    Science.gov (United States)

    2012-08-01

    High -­‐ temperature  SMAs 24 Braze  Joint  between  two  wrought  pieces  of  a  Ni24.5Pd25Ti50.5  HTSMA   (HTSMA  from...process  can  be  used   to  join  other  metal  alloys  and   high -­‐ temperature   SMAs 25 Cellular  Shape  Memory...20 30 40 50 60 910 3 4 8 5 2 T (°C) Shape memory & superelasticity 1 0 e (%) (GPa) 6 7 A NiTi wire

  8. A sharp interface evolutionary model for shape memory alloys

    Czech Academy of Sciences Publication Activity Database

    Knüpfer, H.; Kružík, Martin

    2016-01-01

    Roč. 96, č. 11 (2016), s. 1347-1355 ISSN 0044-2267 R&D Projects: GA ČR GA14-15264S Institutional support: RVO:67985556 Keywords : Polyconvexity * shape memory materials * rate-independent problems Subject RIV: BA - General Mathematics Impact factor: 1.332, year: 2016 http://library.utia.cas.cz/separaty/2016/MTR/kruzik-0465809.pdf

  9. Magnetic shape-memory alloys: thermomechanical modelling and analysis

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš; Stefanelli, U.

    2014-01-01

    Roč. 26, č. 6 (2014), s. 783-810 ISSN 0935-1175 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:61388998 Keywords : magnetic shape- memory alloys * martensitic phase transformation * ferro/paramagnetic phase transformation Subject RIV: BA - General Mathematics Impact factor: 1.779, year: 2014 http://link.springer.com/article/10.1007/s00161-014-0339-8#

  10. Wind turbine model and loop shaping controller design

    Science.gov (United States)

    Gilev, Bogdan

    2017-12-01

    A model of a wind turbine is evaluated, consisting of: wind speed model, mechanical and electrical model of generator and tower oscillation model. Model of the whole system is linearized around of a nominal point. By using the linear model with uncertainties is synthesized a uncertain model. By using the uncertain model is developed a H∞ controller, which provide mode of stabilizing the rotor frequency and damping the tower oscillations. Finally is simulated work of nonlinear system and H∞ controller.

  11. Modelling human hard palate shape with Bézier curves.

    Directory of Open Access Journals (Sweden)

    Rick Janssen

    Full Text Available People vary at most levels, from the molecular to the cognitive, and the shape of the hard palate (the bony roof of the mouth is no exception. The patterns of variation in the hard palate are important for the forensic sciences and (palaeoanthropology, and might also play a role in speech production, both in pathological cases and normal variation. Here we describe a method based on Bézier curves, whose main aim is to generate possible shapes of the hard palate in humans for use in computer simulations of speech production and language evolution. Moreover, our method can also capture existing patterns of variation using few and easy-to-interpret parameters, and fits actual data obtained from MRI traces very well with as little as two or three free parameters. When compared to the widely-used Principal Component Analysis (PCA, our method fits actual data slightly worse for the same number of degrees of freedom. However, it is much better at generating new shapes without requiring a calibration sample, its parameters have clearer interpretations, and their ranges are grounded in geometrical considerations.

  12. Rib Geometry Explains Variation in Dynamic Structural Response: Potential Implications for Frontal Impact Fracture Risk.

    Science.gov (United States)

    Murach, Michelle M; Kang, Yun-Seok; Goldman, Samuel D; Schafman, Michelle A; Schlecht, Stephen H; Moorhouse, Kevin; Bolte, John H; Agnew, Amanda M

    2017-09-01

    The human thorax is commonly injured in motor vehicle crashes, and despite advancements in occupant safety rib fractures are highly prevalent. The objective of this study was to quantify the ability of gross and cross-sectional geometry, separately and in combination, to explain variation of human rib structural properties. One hundred and twenty-two whole mid-level ribs from 76 fresh post-mortem human subjects were tested in a dynamic frontal impact scenario. Structural properties (peak force and stiffness) were successfully predicted (p rib cross-sectional geometry obtained via direct histological imaging (total area, cortical area, and section modulus) and were improved further when utilizing a combination of cross-sectional and gross geometry (robusticity, whole bone strength index). Additionally, preliminary application of a novel, adaptive thresholding technique, allowed for total area and robusticity to be measured on a subsample of standard clinical CT scans with varied success. These results can be used to understand variation in individual rib response to frontal loading as well as identify important geometric parameters, which could ultimately improve injury criteria as well as the biofidelity of anthropomorphic test devices (ATDs) and finite element (FE) models of the human thorax.

  13. 3D active shape and appearance models in cardiac image analysis

    NARCIS (Netherlands)

    Lelieveldt, B.P.F.; Frangi, A.F.; Mitchell, S.C.; Assen, van H.C.; Ordás, S.; Reiber, J.H.C.; Sonka, M.; Paragios, N.; Chen, Y.; Faugeras, O.

    2006-01-01

    This chapter introduces statistical shape- and appearance models and their biomedical applications. Three- and four-dimensional extension of these models are the main focus. Approaches leading to automated landmark definition are introduced and discussed. The applicability is underlined by

  14. Flow regime mapping of vertical two-phase downflow in a ribbed annulus

    International Nuclear Information System (INIS)

    Kielpinski, A.L.

    1992-01-01

    Two-phase flow regimes have been mapped for vertical, cocurrent downflow in a narrow annulus which is partially segmented by the presence of longitudinal ribs. This geometry and flow condition has application to the analysis of a Large-Break Loss of Coolant Accident (LB-LOCA) in the production K-Reactor at the Savannah River Site (SRS). The ribbed annular geometry, particularly the presence of non-sealing ribs, gives rise to some unique phenomenological features. The flow behavior is influenced by the partial segmentation of the annulus into four quadrants or subchannels. A random element is induced by the natural bowing of the slender tubes; the width of the azimuthal flow path between two subchannels at a given axial location is indeterminate, and can take on any value between zero and the maximum clearance of 7.6 x l0 -4 m. When the rib gap is zero at a given location, it is at a maximum 180P away at the same axial location. The range of rib gaps is spanned in a single test section, as it would be also in a reactor assembly. As a result of these effects, flow regime maps obtained by other researchers for downflow in annuli are not accurate for defining flow regimes in a ribbed annulus. Flow regime transitions similar to those noted by, e.g., Bamea, were observed; the locations of these transitions were displaced with respect to the transition equations derived by Bamea. Experimental bubble rise velocity measurements were also obtained in the same test section. The bubble rise velocities were much higher than expected from the theory developed for slug bubbles in tubes, unribbed annuli, and rectangular channels. An elliptical-cap bubble rises faster than a slug bubble of the same area. Large, slug-shaped bubbles injected into the test section were observed to reduce in size as they rose, due to interaction with a longitudinal rib. They thereby adopted a shape more like an elliptical-cap bubble, hence rising faster than the original slug bubble

  15. Exploring Modeling Options and Conversion of Average Response to Appropriate Vibration Envelopes for a Typical Cylindrical Vehicle Panel with Rib-stiffened Design

    Science.gov (United States)

    Harrison, Phil; LaVerde, Bruce; Teague, David

    2009-01-01

    Although applications for Statistical Energy Analysis (SEA) techniques are more widely used in the aerospace industry today, opportunities to anchor the response predictions using measured data from a flight-like launch vehicle structure are still quite valuable. Response and excitation data from a ground acoustic test at the Marshall Space Flight Center permitted the authors to compare and evaluate several modeling techniques available in the SEA module of the commercial code VA One. This paper provides an example of vibration response estimates developed using different modeling approaches to both approximate and bound the response of a flight-like vehicle panel. Since both vibration response and acoustic levels near the panel were available from the ground test, the evaluation provided an opportunity to learn how well the different modeling options can match band-averaged spectra developed from the test data. Additional work was performed to understand the spatial averaging of the measurements across the panel from measured data. Finally an evaluation/comparison of two conversion approaches from the statistical average response results that are output from an SEA analysis to a more useful envelope of response spectra appropriate to specify design and test vibration levels for a new vehicle.

  16. Computational study on effects of rib height and thickness on heat ...

    Indian Academy of Sciences (India)

    A computational study was carried out for the heat transfer augmentation in a three-dimensional square channel fitted with different types of ribs. The standard k–e model and its two variants (RNG and realizable) were used for turbulence modeling. The predictions were compared with available experimental ...

  17. A Solvable Model for Nuclear Shape Phase Transitions

    International Nuclear Information System (INIS)

    Levai, G.; Arias, J. M.

    2009-01-01

    There has been considerable interest recently in phase transitions that occur between some well-defined nuclear shapes, e.g. the spherical vibrator, the axially deformed rotor and the γ-unstable rotor, which are assigned to the U(5), SU(3) and 0(6) symmetries. These shape phase transitions occur through critical points of the IBM phase diagram and correspond to rapid structural changes. The first transition of this type describes transition form the spherical to the γ-unstable phase and has been associated with an E(5) symmetry. Later further critical point symmetries e.g. X(5) and Y(5) have also been proposed for transitions between other nuclear shape phases. In another application the chain of even Ru isotopes was considered from A 98 to 112 [2]. The parameters were extracted from a fit to the low-lying energy spectrum of each nucleus and were used to plot the corresponding potential. It was found that up to A =102 the potential is essentially an harmonic oscillator, while at A =104 a rather flat potential was seen, in accordance with the expected phase transition and E(5) symmetry there. With increasing A then the minimum got increasingly deeper and moved away from β = 0. We discuss the possibility of generalizing the formalism in two ways: first by including dependence on the 7 variable allowing for the approximate description of nuclei close to the X(5) symmetry, and second, including higher-lying energy levels in the quasi-exactly solvable formalism

  18. Genetic Fuzzy Modelling of User Perception of 3D Shapes

    DEFF Research Database (Denmark)

    Achiche, Sofiane; Ahmed-Kristensen, Saeema

    2011-01-01

    Defining the aesthetic and emotional value of a product is an important consideration for its design. Furthermore, if several designers are faced with the task of creating an object that describe a certain emotion/perception (aggressive, soft, heavy, etc.), each is most likely to interpret...... the emotion/perception with different shapes composed of a set of different geometric features. In this paper, the authors propose an automatic approach to formalize the relationships between geometric information of 3D objects and the intended emotional content using fuzzy logic. In addition...

  19. Nonlinear Model of Pseudoelastic Shape Memory Alloy Damper Considering Residual Martensite Strain Effect

    Directory of Open Access Journals (Sweden)

    Y. M. Parulekar

    2012-01-01

    Full Text Available Recently, there has been increasing interest in using superelastic shape memory alloys for applications in seismic resistant-design. Shape memory alloys (SMAs have a unique property by which they can recover their original shape after experiencing large strains up to 8% either by heating (shape memory effect or removing stress (pseudoelastic effect. Many simplified shape memory alloy models are suggested in the past literature for capturing the pseudoelastic response of SMAs in passive vibration control of structures. Most of these models do not consider the cyclic effects of SMA's and resulting residual martensite deformation. Therefore, a suitable constitutive model of shape memory alloy damper which represents the nonlinear hysterical dynamic system appropriately is essential. In this paper a multilinear hysteretic model incorporating residual martensite strain effect of pseudoelastic shape memory alloy damper is developed and experimentally validated using SMA wire, based damper device. A sensitivity analysis is done using the proposed model along with three other simplified SMA models. The models are implemented on a steel frame representing an SDOF system and the comparison of seismic response of structure with all the models is made in the numerical study.

  20. Development of a statistical shape model of multi-organ and its performance evaluation

    International Nuclear Information System (INIS)

    Nakada, Misaki; Shimizu, Akinobu; Kobatake, Hidefumi; Nawano, Shigeru

    2010-01-01

    Existing statistical shape modeling methods for an organ can not take into account the correlation between neighboring organs. This study focuses on a level set distribution model and proposes two modeling methods for multiple organs that can take into account the correlation between neighboring organs. The first method combines level set functions of multiple organs into a vector. Subsequently it analyses the distribution of the vectors of a training dataset by a principal component analysis and builds a multiple statistical shape model. Second method constructs a statistical shape model for each organ independently and assembles component scores of different organs in a training dataset so as to generate a vector. It analyses the distribution of the vectors of to build a statistical shape model of multiple organs. This paper shows results of applying the proposed methods trained by 15 abdominal CT volumes to unknown 8 CT volumes. (author)

  1. Osteoradionecrosis of the Ribs following Breast Radiotherapy

    Directory of Open Access Journals (Sweden)

    Luke Nicholls

    2015-08-01

    Full Text Available Introduction: Osteoradionecrosis (ORN of the chest wall is a rare complication after whole-breast radiotherapy (RT. Herein, we report a case of ORN involving the underlying ribs following adjuvant whole-breast RT using standard fractionation and conduct a review of the literature. Case Report: A previously well 43-year-old female with right-sided, early-stage, node-negative breast cancer was treated with breast-conserving surgery. She subsequently underwent adjuvant whole-breast RT receiving 50 Gy in 25 fractions over 5 weeks using standard tangential photon fields with 6 MV photons followed by an electron boost of 10 Gy in 5 fractions according to International Commission on Radiation Units (ICRU requirements. Eleven months after RT, the patient developed right lateral chest wall pain, with magnetic resonance imaging (MRI demonstrating two fractures involving the underlying right fifth and sixth ribs associated with fatty marrow changes in the second to sixth ribs, thus raising the possibility of ORN. Treatments including hyperbaric oxygen, pentoxifylline and vitamin E were used with symptomatic improvements. There was demonstrable resolution on follow-up MRI at 2.5 years. Conclusion: The incidence of ORN utilising modern RT techniques and standard fractionation is rare. Numerous treatments are available, with variable response rates. Emerging evidence of predictive gene profiling to estimate the risk of radiation sensitivity may assist in individualising preventative strategies to mitigate the risk of ORN.

  2. [Tuberculosis of the spine and ribs].

    Science.gov (United States)

    Wishnitzer, R; Landow, Z; Sagiv, S; Rozenhack, M; Eliraz, A

    1991-11-15

    Tuberculosis of the spine or ribs is uncommon, occurring in less than 1% of patients with tuberculosis (TB). 2 women are presented who recently immigrated from Ethiopia and India, respectively. One, aged 55, presented with chest pain, fatigue and several masses under the skin of the scalp. Chest X-ray and CT scan suggested Pancoast tumor, and the lateral parts of the first 2 right ribs were absent. The origin of the patient, clinical findings and positive PPD suggested TB of the ribs and anti-TB therapy resulted in cure. The diagnosis was later confirmed by a positive culture. The other woman, aged 68, presented with fatigue, mild abdominal pain and axillary lymphadenopathy. The PPD was positive and X-ray showed widening of the mediastinum. A caseating granuloma with Langhans epithelioid cells was found in a lymph node. Flaccid paraparesis developed before therapy was started. CT scan showed a typical picture of TB affecting the T3-T6 vertebrae. Drainage of a cold abscess of the spine via the anterior approach was followed by anti-TB therapy. Culture of a biopsied lymph node and of pus obtained at operation confirmed the diagnosis of TB. The patient died 2 months later from gastrointestinal bleeding. Awareness of the unusual presentations of various forms of TB is mandatory in countries with immigration from countries in which TB is still common.

  3. Adapting Active Shape Models for 3D segmentation of tubular structures in medical images.

    Science.gov (United States)

    de Bruijne, Marleen; van Ginneken, Bram; Viergever, Max A; Niessen, Wiro J

    2003-07-01

    Active Shape Models (ASM) have proven to be an effective approach for image segmentation. In some applications, however, the linear model of gray level appearance around a contour that is used in ASM is not sufficient for accurate boundary localization. Furthermore, the statistical shape model may be too restricted if the training set is limited. This paper describes modifications to both the shape and the appearance model of the original ASM formulation. Shape model flexibility is increased, for tubular objects, by modeling the axis deformation independent of the cross-sectional deformation, and by adding supplementary cylindrical deformation modes. Furthermore, a novel appearance modeling scheme that effectively deals with a highly varying background is developed. In contrast with the conventional ASM approach, the new appearance model is trained on both boundary and non-boundary points, and the probability that a given point belongs to the boundary is estimated non-parametrically. The methods are evaluated on the complex task of segmenting thrombus in abdominal aortic aneurysms (AAA). Shape approximation errors were successfully reduced using the two shape model extensions. Segmentation using the new appearance model significantly outperformed the original ASM scheme; average volume errors are 5.1% and 45% respectively.

  4. Design reuse in product shape modeling : A study of freeform feature reuse by signal processing techniques

    NARCIS (Netherlands)

    Wang, C.

    2005-01-01

    Lack of facilities in supporting design reuse is a serious problem in product shape modeling, especially in computer-aided design systems. This becomes a bottleneck of fast shape conceptualization and creation in consumer product design, which consequently prohibits creativity and innovation. In the

  5. ShapeSelectForest: a new r package for modeling landsat time series

    Science.gov (United States)

    Mary Meyer; Xiyue Liao; Gretchen Moisen; Elizabeth Freeman

    2015-01-01

    We present a new R package called ShapeSelectForest recently posted to the Comprehensive R Archival Network. The package was developed to fit nonparametric shape-restricted regression splines to time series of Landsat imagery for the purpose of modeling, mapping, and monitoring annual forest disturbance dynamics over nearly three decades. For each pixel and spectral...

  6. Shapes of nuclear configurations in a cranked harmonic oscillator model

    International Nuclear Information System (INIS)

    Troudet, T.; Arvieu, R.

    1980-05-01

    The shapes of nuclear configurations are calculated using Slater determinants built with cranked harmonic oscillator single particle states. The nuclear forces role is played by a volume conservation condition (of the potential or of the density) in a first part. In a second part, we have used the finite range, density dependent interaction of Cogny. A very simple classification of configurations emerges in the first part, the relevant parameter being the equatorial eccentricity of the nuclear density. A critical equatorial eccentricity is obtained which governs the accession to the case for which the nucleus is oblate and symmetric around its axis of rotation. Nuclear configurations calculated in the second part observe remarkably well these behaviors

  7. COMPUTATIONAL MODELING OF AIRFLOW IN NONREGULAR SHAPED CHANNELS

    Directory of Open Access Journals (Sweden)

    A. A. Voronin

    2013-05-01

    Full Text Available The basic approaches to computational modeling of airflow in the human nasal cavity are analyzed. Different models of turbulent flow which may be used in order to calculate air velocity and pressure are discussed. Experimental measurement results of airflow temperature are illustrated. Geometrical model of human nasal cavity reconstructed from computer-aided tomography scans and numerical simulation results of airflow inside this model are also given. Spatial distributions of velocity and temperature for inhaled and exhaled air are shown.

  8. Experimental investigation of heat transfer and flow using V and broken V ribs within gas turbine blade cooling passage

    Science.gov (United States)

    Kumar, Sourabh; Amano, R. S.

    2015-05-01

    Gas turbines are extensively used for aircraft propulsion, land-based power generation, and various industrial applications. With an increase in turbine rotor inlet temperatures, developments in innovative gas turbine cooling technology enhance the efficiency and power output; these advancements of turbine cooling have allowed engine designs to exceed normal material temperature limits. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream of gas are based on an increase in the heat transfer areas and on the promotion of turbulence of the cooling flow. In this study, an improvement in performance is obtained by casting repeated continuous V- and broken V-shaped ribs on one side of the two pass square channels into the core of the blade. A detailed experimental investigation is done for two pass square channels with a 180° turn. Detailed heat transfer distribution occurring in the ribbed passage is reported for a steady state experiment. Four different combinations of 60° V- and broken 60° V-ribs in a channel are considered. A series of thermocouples are used to obtain the temperature on the channel surface and local heat transfer coefficients are obtained for Reynolds numbers 16,000, 56,000 and 85,000 within the turbulent flow regime. Area averaged data are calculated in order to compare the overall performance of the tested ribbed surface and to evaluate the degree of heat transfer enhancement induced by the rib. Flow within the channels is characterized by heat transfer enhancing ribs, bends, rotation and buoyancy effects. A series of experimental measurements is performed to predict the overall performance of the channel. This paper presents an attempt to collect information about the Nusselt number, the pressure drop and the overall performance of the eight different ribbed ducts at the specified Reynolds number. The main contribution of this study is to evaluate the best combination of rib arrangements

  9. ribB and ribBA genes from Acidithiobacillus ferrooxidans: expression levels under different growth conditions and phylogenetic analysis.

    Science.gov (United States)

    Knegt, Fábio H P; Mello, Luciane V; Reis, Fernanda C; Santos, Marcos T; Vicentini, Renato; Ferraz, Lúcio F C; Ottoboni, Laura M M

    2008-01-01

    Acidithiobacillus ferrooxidans is a Gram-negative, chemolithoautotrophic bacterium involved in metal bioleaching. Using the RNA arbitrarily primed polymerase chain reaction (RAP-PCR), we have identified several cDNAs that were differentially expressed when A. ferrooxidans LR was submitted to potassium- and phosphate-limiting conditions. One of these cDNAs showed similarity with ribB. An analysis of the A. ferrooxidans ATCC 23270 genome, made available by The Institute for Genomic Research, showed that the ribB gene was not located in the rib operon, but a ribBA gene was present in this operon instead. The ribBA gene was isolated from A. ferrooxidans LR and expression of both ribB and ribBA was investigated. Transcript levels of both genes were enhanced in cells grown in the absence of K2HPO4, in the presence of zinc and copper sulfate and in different pHs. Transcript levels decreased upon exposure to a temperature higher than the ideal 30 degrees C and at pH 1.2. A comparative genomic analysis using the A. ferrooxidans ATCC 23270 genome revealed similar putative regulatory elements for both genes. Moreover, an RFN element was identified upstream from the ribB gene. Phylogenetic analysis of the distribution of RibB and RibBA in bacteria showed six different combinations. We suggest that the presence of duplicated riboflavin synthesis genes in bacteria must provide their host with some benefit in certain stressful situations.

  10. The RIB production target for the SPES project

    Science.gov (United States)

    Monetti, Alberto; Andrighetto, Alberto; Petrovich, Carlo; Manzolaro, Mattia; Corradetti, Stefano; Scarpa, Daniele; Rossetto, Francesco; Martinez Dominguez, Fernando; Vasquez, Jesus; Rossignoli, Massimo; Calderolla, Michele; Silingardi, Roberto; Mozzi, Aldo; Borgna, Francesca; Vivian, Gianluca; Boratto, Enrico; Ballan, Michele; Prete, Gianfranco; Meneghetti, Giovanni

    2015-10-01

    Facilities making use of the Isotope Separator On-Line (ISOL) method for the production of Radioactive Ion Beams (RIB) attract interest because they can be used for nuclear structure and reaction studies, astrophysics research and interdisciplinary applications. The ISOL technique is based on the fast release of the nuclear reaction products from the chosen target material together with their ionization into short-lived nuclei beams. Within this context, the SPES (Selective Production of Exotic Species) facility is now under construction in Italy at INFN-LNL (Istituto Nazionale di Fisica Nucleare — Laboratori Nazionali di Legnaro). The SPES facility will produce RIBs mainly from n-rich isotopes obtained by a 40 MeV cyclotron proton beam (200 μA) directly impinging on a uranium carbide multi-foil fission target. The aim of this work is to describe and update, from a comprehensive point of view, the most important results obtained by the analysis of the on-line behavior of the SPES production target assembly. In particular an improved target configuration has been studied by comparing different codes and physics models: the thermal analyses and the isotope production are re-evaluated. Then some consequent radioprotection aspects, which are essential for the installation and operation of the facility, are presented.

  11. Rib fracture repair: indications, technical issues, and future directions.

    Science.gov (United States)

    Nirula, Raminder; Diaz, Jose J; Trunkey, Donald D; Mayberry, John C

    2009-01-01

    Rib fracture repair has been performed at selected centers around the world for more than 50 years; however, the operative indications have not been established and are considered controversial. The outcome of a strictly nonoperative approach may not be optimal. Potential indications for rib fracture repair include flail chest, painful, movable rib fractures refractory to conventional pain management, chest wall deformity/defect, rib fracture nonunion, and during thoracotomy for other traumatic indication. Rib fracture repair is technically challenging secondary to the human rib's relatively thin cortex and its tendency to fracture obliquely. Nonetheless, several effective repair systems have been developed. Future directions for progress on this important surgical problem include the development of minimally invasive techniques and the conduct of multicenter, randomized trials.

  12. The Place of Ultrasonography in the Evaluation of Rib Fractures

    Directory of Open Access Journals (Sweden)

    Fulya Bakılan

    2015-12-01

    Full Text Available Objective: The aim of this study was to investigate whether ultrasonography is superior to chest x-ray in detecting rib fractures in patients with minor blunt chest trauma and chest pain. Materials and Methods: Ultrasonography findings of 32 patients with minor blunt chest trauma showing no evidence of a rib fracture on anteroposterior chest x-rays, were documented. Presence of cortical discontinuities, acoustic shadows, reverberation artifacts, and hematoma by ultrasonography was proposed as the diagnostic criteria for detecting the rib fracture. Results: Rib fracture was detected in 20 patients (62.5% according to ultrasonography results. A mildly displaced fracture was detected in 7 patients (35%, hematoma was detected in 3 patients (15% and multiple fractures (in 5th, 6th, 7th, and 8th ribs were detected in 1 patient (5%. Conclusion: The results of our study showed that ultrasonography is superior to chest x-ray, in detecting rib fractures.

  13. Evaluation of the Rib Lesions by Bone Scanning

    International Nuclear Information System (INIS)

    Park, Hyung Gun; Lee, Dong Soo; Lee, Myung Chul; Cho, Bo Youn; Koh, Chang Soon

    1983-01-01

    In order to establish criteria for distinguishing between occult fracture and metastases, we have reviewed 52 records of cancer patients and 24 of rib fracture patients referred for bone scanning. In 52 patients with biopsy-proven malignancy, multiple linear increased uptake of the ribs was found in 32 cases(61.5%), and was the most common finding. In 24 patients with rib fracture, all but 1 had fecal increased uptake of the ribs, and lesions almost always aligned in a row. By analyzing the appearance of rib lesions in total 76 patients, it was concluded that there is a high probability that rib lesions detected by bone scanning are bony metastases if 1) they are multiple linear as opposed to fecal, and 2) they are not aligned in the same location

  14. Bifid rib – usefulness of chest ultrasound. A case report

    Directory of Open Access Journals (Sweden)

    Magdalena Kryger

    2013-12-01

    Full Text Available The paper presents the possibility of using ultrasonography in the diagnosis of a congenital rib anomaly in the form of bifid rib. Bifid rib is a rare congenital abnormality of anterior chest wall. It manifests as a chest “lump.” Such lesions are detected during a routine physical examination or chest X-ray which is often performed for other reasons. The overall prevalence of bifid rib is estimated at 0.15% to 3.4% (mean 2% and it accounts for approximately 20% of all congenital rib anomalies. It is usually an unilateral lesion. The cases presented herein constitute the first pediatric cases in the available literature in which bifid rib anomaly was visualized by ultrasound examination.

  15. Shape: A 3D Modeling Tool for Astrophysics.

    Science.gov (United States)

    Steffen, Wolfgang; Koning, Nicholas; Wenger, Stephan; Morisset, Christophe; Magnor, Marcus

    2011-04-01

    We present a flexible interactive 3D morpho-kinematical modeling application for astrophysics. Compared to other systems, our application reduces the restrictions on the physical assumptions, data type, and amount that is required for a reconstruction of an object's morphology. It is one of the first publicly available tools to apply interactive graphics to astrophysical modeling. The tool allows astrophysicists to provide a priori knowledge about the object by interactively defining 3D structural elements. By direct comparison of model prediction with observational data, model parameters can then be automatically optimized to fit the observation. The tool has already been successfully used in a number of astrophysical research projects.

  16. The design of a radio frequency quadrupole LINAC for the RIB ...

    Indian Academy of Sciences (India)

    Logo of the Indian Academy of Sciences. Indian Academy of Sciences ... Physics; Volume 59; Issue 6. The design of a radio frequency quadrupole LINAC for the RIB project at VECC Kolkata ... rf structure design study. The beam dynamics and rf-structure design along with the results of the cold model tests will be presented.

  17. Automatic three-dimensional rib centerline extraction from CT scans for enhanced visualization and anatomical context

    Science.gov (United States)

    Ramakrishnan, Sowmya; Alvino, Christopher; Grady, Leo; Kiraly, Atilla

    2011-03-01

    We present a complete automatic system to extract 3D centerlines of ribs from thoracic CT scans. Our rib centerline system determines the positional information for the rib cage consisting of extracted rib centerlines, spinal canal centerline, pairing and labeling of ribs. We show an application of this output to produce an enhanced visualization of the rib cage by the method of Kiraly et al., in which the ribs are digitally unfolded along their centerlines. The centerline extraction consists of three stages: (a) pre-trace processing for rib localization, (b) rib centerline tracing, and (c) post-trace processing to merge the rib traces. Then we classify ribs from non-ribs and determine anatomical rib labeling. Our novel centerline tracing technique uses the Random Walker algorithm to segment the structural boundary of the rib in successive 2D cross sections orthogonal to the longitudinal direction of the ribs. Then the rib centerline is progressively traced along the rib using a 3D Kalman filter. The rib centerline extraction framework was evaluated on 149 CT datasets with varying slice spacing, dose, and under a variety of reconstruction kernels. The results of the evaluation are presented. The extraction takes approximately 20 seconds on a modern radiology workstation and performs robustly even in the presence of partial volume effects or rib pathologies such as bone metastases or fractures, making the system suitable for assisting clinicians in expediting routine rib reading for oncology and trauma applications.

  18. PIV Measurements of Turbulent Flow in a Channel with Solid or Perforated Ribs

    DEFF Research Database (Denmark)

    Wang, Lei; Salewski, Mirko; Sundén, Bengt

    2011-01-01

    Particle image velocimetry measurements are performed in a channel with periodic ribs on one wall. We investigate the flow around two different rib configurations: solid and perforated ribs with a slit. The ribs obstruct the channel by 20% of its height and are arranged 10 rib heights apart. For ...

  19. Correction tool for Active Shape Model based lumbar muscle segmentation.

    Science.gov (United States)

    Valenzuela, Waldo; Ferguson, Stephen J; Ignasiak, Dominika; Diserens, Gaelle; Vermathen, Peter; Boesch, Chris; Reyes, Mauricio

    2015-08-01

    In the clinical environment, accuracy and speed of the image segmentation process plays a key role in the analysis of pathological regions. Despite advances in anatomic image segmentation, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a low number of interactions, and a user-independent solution. In this work we present a new interactive correction method for correcting the image segmentation. Given an initial segmentation and the original image, our tool provides a 2D/3D environment, that enables 3D shape correction through simple 2D interactions. Our scheme is based on direct manipulation of free form deformation adapted to a 2D environment. This approach enables an intuitive and natural correction of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle segmentation from Magnetic Resonance Images. Experimental results show that full segmentation correction could be performed within an average correction time of 6±4 minutes and an average of 68±37 number of interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.03.

  20. An analysis of 214 cases of rib fractures

    OpenAIRE

    Karadayi, Sule; Nadir, Aydin; Sahin, Ekber; Celik, Burcin; Arslan, Sulhattin; Kaptanoglu, Melih

    2011-01-01

    INTRODUCTION: Rib fractures are the most common type of injury associated with trauma to the thorax. In this study, we investigated whether morbidity and mortality rates increased in correlation with the number of fractured ribs. MATERIALS AND METHODS: Data from 214 patients with rib fractures who applied or were referred to our clinic between January 2007 and December 2008 were retrospectively evaluated. The patients were allocated into three groups according to the number of fractures: 1) p...

  1. Radiographic abnormalities of ribs in β-thalassemic children

    International Nuclear Information System (INIS)

    Singcharoen, T.; Piyachon, C.; Kulapongs, P.

    1988-01-01

    Bone change is one of the most outstanding manifestations of marrow hyperplasia in thalassemia patients. In the thorax, marrow hyperplasia widens the ribs, thins the cortices, and erases most of their trabecular patterns. Thus, a variety of radiologic changes of the ribs have been described. The chest radiographs of 33 Thai children with β-thalassemia major were reviewed, and a spectrum of rib changes were observed

  2. Flow instability and critical heat flux in a ribbed annulus

    International Nuclear Information System (INIS)

    Yang, B.W.; Dougherty, T.; Fighetti, C.; Kokolis, S.; Reddy, G.D.; McAssey, E.V. Jr.; Coutts, A.

    1993-01-01

    An experimental program has been conducted to determine the onset of flow instability point in a heated annulus which is divided into four sub channels by non-conducting ribs. The onset of flow instability is identified by the minimum point in the pressure drop-velocity curve. Comparison with a ribless annulus show that the presence of ribs increases the minimum point velocity. In addition, data are presented which show that under certain conditions premature CHF can be induced by the ribs

  3. Mathematical modelling of the viable epidermis: impact of cell shape and vertical arrangement

    KAUST Repository

    Wittum, Rebecca; Naegel, Arne; Heisig, Michael; Wittum, Gabriel

    2017-01-01

    In-silico methods are valuable tools for understanding the barrier function of the skin. The key benefit is that mathematical modelling allows the interplay between cell shape and function to be elucidated. This study focuses on the viable (living

  4. A phenomenological two-phase constitutive model for porous shape memory alloys

    KAUST Repository

    El Sayed, Tamer S.; Gurses, Ercan; Siddiq, Amir Mohammed

    2012-01-01

    , application of the presented constitutive model has been presented by performing finite element simulations of the deformation and failure in unaixial dog-bone shaped specimen and compact tension (CT) test specimen. Results show a good agreement

  5. A Preisach type model for temperature driven hysteresis memory erasure in shape memory materials

    OpenAIRE

    Kopfová, J.; Krejčí, P. (Pavel)

    2011-01-01

    We establish the well-posedness and thermodynamic consistency of a variational inequality modeling temperature-induced memory erasure in shape memory materials. It is shown that the input-output operator is continuous with respect to uniform convergence.

  6. An integrated numerical model for the prediction of Gaussian and billet shapes

    International Nuclear Information System (INIS)

    Hattel, J.H.; Pryds, N.H.; Pedersen, T.B.

    2004-01-01

    Separate models for the atomisation and the deposition stages were recently integrated by the authors to form a unified model describing the entire spray-forming process. In the present paper, the focus is on describing the shape of the deposited material during the spray-forming process, obtained by this model. After a short review of the models and their coupling, the important factors which influence the resulting shape, i.e. Gaussian or billet, are addressed. The key parameters, which are utilized to predict the geometry and dimension of the deposited material, are the sticking efficiency and the shading effect for Gaussian and billet shape, respectively. From the obtained results, the effect of these parameters on the final shape is illustrated

  7. Automatic lung segmentation in functional SPECT images using active shape models trained on reference lung shapes from CT.

    Science.gov (United States)

    Cheimariotis, Grigorios-Aris; Al-Mashat, Mariam; Haris, Kostas; Aletras, Anthony H; Jögi, Jonas; Bajc, Marika; Maglaveras, Nicolaos; Heiberg, Einar

    2018-02-01

    Image segmentation is an essential step in quantifying the extent of reduced or absent lung function. The aim of this study is to develop and validate a new tool for automatic segmentation of lungs in ventilation and perfusion SPECT images and compare automatic and manual SPECT lung segmentations with reference computed tomography (CT) volumes. A total of 77 subjects (69 patients with obstructive lung disease, and 8 subjects without apparent perfusion of ventilation loss) performed low-dose CT followed by ventilation/perfusion (V/P) SPECT examination in a hybrid gamma camera system. In the training phase, lung shapes from the 57 anatomical low-dose CT images were used to construct two active shape models (right lung and left lung) which were then used for image segmentation. The algorithm was validated in 20 patients, comparing its results to reference delineation of corresponding CT images, and by comparing automatic segmentation to manual delineations in SPECT images. The Dice coefficient between automatic SPECT delineations and manual SPECT delineations were 0.83 ± 0.04% for the right and 0.82 ± 0.05% for the left lung. There was statistically significant difference between reference volumes from CT and automatic delineations for the right (R = 0.53, p = 0.02) and left lung (R = 0.69, p automatic quantification of wide range of measurements.

  8. New Approaches For Asteroid Spin State and Shape Modeling From Delay-Doppler Radar Images

    Science.gov (United States)

    Raissi, Chedy; Lamee, Mehdi; Mosiane, Olorato; Vassallo, Corinne; Busch, Michael W.; Greenberg, Adam; Benner, Lance A. M.; Naidu, Shantanu P.; Duong, Nicholas

    2016-10-01

    Delay-Doppler radar imaging is a powerful technique to characterize the trajectories, shapes, and spin states of near-Earth asteroids; and has yielded detailed models of dozens of objects. Reconstructing objects' shapes and spins from delay-Doppler data is a computationally intensive inversion problem. Since the 1990s, delay-Doppler data has been analyzed using the SHAPE software. SHAPE performs sequential single-parameter fitting, and requires considerable computer runtime and human intervention (Hudson 1993, Magri et al. 2007). Recently, multiple-parameter fitting algorithms have been shown to more efficiently invert delay-Doppler datasets (Greenberg & Margot 2015) - decreasing runtime while improving accuracy. However, extensive human oversight of the shape modeling process is still required. We have explored two new techniques to better automate delay-Doppler shape modeling: Bayesian optimization and a machine-learning neural network.One of the most time-intensive steps of the shape modeling process is to perform a grid search to constrain the target's spin state. We have implemented a Bayesian optimization routine that uses SHAPE to autonomously search the space of spin-state parameters. To test the efficacy of this technique, we compared it to results with human-guided SHAPE for asteroids 1992 UY4, 2000 RS11, and 2008 EV5. Bayesian optimization yielded similar spin state constraints within a factor of 3 less computer runtime.The shape modeling process could be further accelerated using a deep neural network to replace iterative fitting. We have implemented a neural network with a variational autoencoder (VAE), using a subset of known asteroid shapes and a large set of synthetic radar images as inputs to train the network. Conditioning the VAE in this manner allows the user to give the network a set of radar images and get a 3D shape model as an output. Additional development will be required to train a network to reliably render shapes from delay

  9. Modelling research on determining shape coefficients for subdivision interpretation in γ-ray spectral logging

    International Nuclear Information System (INIS)

    Yin Wangming; She Guanjun; Tang Bin

    2011-01-01

    This paper first describes the physical meaning of the shape coefficients in the subdivision interpretation of γ-ray logging; then discusses the theory, method to determine the practical shape coefficients with logging model and defines the formula to approximately calculate the coefficients. A great deal of experimental work has been preformed with a HPGe γ-ray spectrometer and reached satisfied result which has validated the effeciency of the modelling method. (authors)

  10. Rib fracture following stereotactic body radiotherapy: a potential pitfall.

    Science.gov (United States)

    Stanic, Sinisa; Boike, Thomas P; Rule, William G; Timmerman, Robert D

    2011-11-01

    Although the incidence of rib fractures after conventional radiotherapy is generally low (rib fractures are a relatively common complication of stereotactic body radiotherapy. For malignancy adjacent to the chest wall, the incidence of rib fractures after stereotactic body radiotherapy is as high as 10%. Unrecognized bone fractures can mimic bone metastases on bone scintigraphy, can lead to extensive workup, and can even lead to consideration of unnecessary systemic chemotherapy, as treatment decisions can be based on imaging findings alone. Nuclear medicine physicians and diagnostic radiologists should always consider rib fracture in the differential diagnosis.

  11. Stress injury of the rib in a swimmer

    Energy Technology Data Exchange (ETDEWEB)

    Heincelman, Carrie [University of Cincinnati Medical Center, Department of Orthopaedic Surgery, Cincinnati, OH (United States); Brown, Seth; England, Eric; Mehta, Kaushal; Wissman, Robert D. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2014-09-15

    Rib stress injuries are uncommonly reported but have been documented among athletes, most notably rowers. There have only been two prior case reports of rib stress injuries in swimmers, both of which were young females. Magnetic resonance (MR) imaging was either not obtained or the imaging characteristics were incompletely described. We present a case of an isolated third rib stress injury in a collegiate male swimmer diagnosed via MR imaging. We briefly discuss the possible etiologies for rib stress injuries, their MR appearance, as well as their treatment. (orig.)

  12. Case report 467: Cystic chondroblastoma left 4th rib

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, M.; McGuire, M.H.; Naunheim, K.; Schajowicz, F.

    1988-03-01

    A case of chondroblastoma in an 18-year-old female arising from a rib near the costotransverse articulation (presumably from the epiphysis of the articular process) has been described. The destructive pattern noted in the rib, associated with a large soft tissue mass, favored a malignant lesion rather than a benign one. Histologically, this tumor had large cystic and hemorrhagic components, consistent with the diagnosis of a cystic chondroblastoma of a rib. Curiously, this patient, like two others with chondroblastoma in a rib was asymptomatic, and attention to the abnormality was drawn from a routine chest radiography. The patient remains disease-free one and a half-years following surgery.

  13. Numerical prediction of turbulent heat transfer augmentation in an annular fuel channel with two-dimensional square ribs

    International Nuclear Information System (INIS)

    Takase, Kazuyuki

    1996-01-01

    The square-ribbed fuel rod for high temperature gas-cooled reactors was developed in order to enhance the turbulent heat transfer in comparison with the standard fuel rod. To evaluate the heat transfer performance of the square-ribbed fuel rod, the turbulent heat transfer coefficients in an annular fuel channel with repeated two-dimensional square ribs were analyzed numerically on a fully developed incompressible flow using the k - ε turbulence model and the two-dimensional axisymmetrical coordinate system. Numerical analyses were carried out for a range of Reynolds numbers from 3000 to 20000 and ratios of square-rib pitch to height of 10, 20 and 40, respectively. The predicted values of the heat transfer coefficients agreed within an error of 10% for the square-rib pitch to height ratio of 10, 20% for 20 and 25% for 40, respectively, with the heat transfer empirical correlations obtained from the experimental data. It was concluded by the present study that the effect of the heat transfer augmentation by square ribs could be predicted sufficiently by the present numerical simulations and also a part of its mechanism could be explained by means of the change in the turbulence kinematic energy distribution along the flow direction. (author)

  14. Numerical prediction of augmented turbulent heat transfer in an annular fuel channel with repeated two-dimensional square ribs

    International Nuclear Information System (INIS)

    Takase, K.

    1996-01-01

    The square-ribbed fuel rod for high temperature gas-cooled reactors was designed and developed so as to enhance the turbulent heat transfer in comparison with the previous standard fuel rod. The turbulent heat transfer characteristics in an annular fuel channel with repeated two-dimensional square ribs were analysed numerically on a fully developed incompressible flow using the k-ε turbulence model and the two-dimensional axisymmetrical coordinate system. Numerical analyses were carried out under the conditions of Reynolds numbers from 3000 to 20000 and ratios of square-rib pitch to height of 10, 20 and 40 respectively. The predictions of the heat transfer coefficients agreed well within an error of 10% for the square-rib pitch to height ratio of 10, 20% for 20 and 25% for 40 respectively, with the heat transfer empirical correlations obtained from the experimental data due to the simulated square-ribbed fuel rods. Therefore it was found that the effect of heat transfer augmentation due to the square ribs could be predicted by the present numerical simulations and the mechanism could be explained by the change in the turbulence kinematic energy distribution along the flow direction. (orig.)

  15. Shape models of asteroids based on lightcurve observations with BlueEye600 robotic observatory

    Science.gov (United States)

    Ďurech, Josef; Hanuš, Josef; Brož, Miroslav; Lehký, Martin; Behrend, Raoul; Antonini, Pierre; Charbonnel, Stephane; Crippa, Roberto; Dubreuil, Pierre; Farroni, Gino; Kober, Gilles; Lopez, Alain; Manzini, Federico; Oey, Julian; Poncy, Raymond; Rinner, Claudine; Roy, René

    2018-04-01

    We present physical models, i.e. convex shapes, directions of the rotation axis, and sidereal rotation periods, of 18 asteroids out of which 10 are new models and 8 are refined models based on much larger data sets than in previous work. The models were reconstructed by the lightcurve inversion method from archived publicly available lightcurves and our new observations with BlueEye600 robotic observatory. One of the new results is the shape model of asteroid (1663) van den Bos with the rotation period of 749 h, which makes it the slowest rotator with known shape. We describe our strategy for target selection that aims at fast production of new models using the enormous potential of already available photometry stored in public databases. We also briefly describe the control software and scheduler of the robotic observatory and we discuss the importance of building a database of asteroid models for studying asteroid physical properties in collisional families.

  16. Shape optimization of metal forming and forging products using the stress equivalent static loads calculated from a virtual model

    International Nuclear Information System (INIS)

    Jang, Hwan Hak; Jeong, Seong Beom; Park, Gyung Jin

    2012-01-01

    A shape optimization is proposed to obtain the desired final shape of forming and forging products in the manufacturing process. The final shape of a forming product depends on the shape parameters of the initial blank shape. The final shape of a forging product depends on the shape parameters of the billet shape. Shape optimization can be used to determine the shape of the blank and billet to obtain the appropriate final forming and forging products. The equivalent static loads method for non linear static response structural optimization (ESLSO) is used to perform metal forming and forging optimization since nonlinear dynamic analysis is required. Stress equivalent static loads (stress ESLs) are newly defined using a virtual model by redefining the value of the material properties. The examples in this paper show that optimization using the stress ESLs is quite useful and the final shapes of a forming and forging products are identical to the desired shapes

  17. Sparse Decomposition and Modeling of Anatomical Shape Variation

    DEFF Research Database (Denmark)

    Sjöstrand, Karl; Rostrup, Egill; Ryberg, Charlotte

    2007-01-01

    counterparts if constructed carefully. In most medical applications, models are required to have both good statistical performance and a relevant clinical interpretation to be of value. Morphometry of the corpus callosum is one illustrative example. This paper presents a method for relating spatial features...... to clinical outcome data. A set of parsimonious variables is extracted using sparse principal component analysis, producing simple yet characteristic features. The relation of these variables with clinical data is then established using a regression model. The result may be visualized as patterns...... two alternative techniques, one where features are derived using a model-based wavelet approach, and one where the original variables are regressed directly on the outcome....

  18. Annular flow transition model in channels of various shapes

    International Nuclear Information System (INIS)

    Osakabe, Masahiro; Tasaka, Kanji; Kawasaki, Yuji.

    1988-01-01

    The annular transition in the rod bundle is interesting because the small gaps between rods exist in the flow area. This is a very important phenomenon in the boiloff accident of nuclear reactor core. As a first attempt, the effect of small gaps in the flow area was studied by using the vertical rectangular ducts with different narrow gaps (2 x 100, 5 x 100, 10 x 100 mm). Based on the experimental results, the transition void fraction was defined and the transition model was proposed. The model gives a good prediction of the wide range of previous experiments including the data taken in the channels with small gaps. (author)

  19. Annular flow transition model in channels of various shapes

    International Nuclear Information System (INIS)

    Osakabe, M.; Tasaka, K.; Kawasaki, Y.

    1989-01-01

    Annular transition in a rod bundle is interesting because small gaps exist between rods in the flow area. This is a very important phenomenon in a boiloff accident of a nuclear reactor core. This paper reports, as a first attempt, the effect of small gaps in the flow area was studied by using vertical rectangular ducts with different narrow gaps (2 x 100, 5 x 100, 10 x 100 mm). Based on the experimental results, the transition void fraction was defined and a transition model is proposed. The model gives a good prediction for a wide range of previous experiments including the data taken in channels with small gaps

  20. Automatic anatomy recognition via multiobject oriented active shape models.

    Science.gov (United States)

    Chen, Xinjian; Udupa, Jayaram K; Alavi, Abass; Torigian, Drew A

    2010-12-01

    This paper studies the feasibility of developing an automatic anatomy recognition (AAR) system in clinical radiology and demonstrates its operation on clinical 2D images. The anatomy recognition method described here consists of two main components: (a) multiobject generalization of OASM and (b) object recognition strategies. The OASM algorithm is generalized to multiple objects by including a model for each object and assigning a cost structure specific to each object in the spirit of live wire. The delineation of multiobject boundaries is done in MOASM via a three level dynamic programming algorithm, wherein the first level is at pixel level which aims to find optimal oriented boundary segments between successive landmarks, the second level is at landmark level which aims to find optimal location for the landmarks, and the third level is at the object level which aims to find optimal arrangement of object boundaries over all objects. The object recognition strategy attempts to find that pose vector (consisting of translation, rotation, and scale component) for the multiobject model that yields the smallest total boundary cost for all objects. The delineation and recognition accuracies were evaluated separately utilizing routine clinical chest CT, abdominal CT, and foot MRI data sets. The delineation accuracy was evaluated in terms of true and false positive volume fractions (TPVF and FPVF). The recognition accuracy was assessed (1) in terms of the size of the space of the pose vectors for the model assembly that yielded high delineation accuracy, (2) as a function of the number of objects and objects' distribution and size in the model, (3) in terms of the interdependence between delineation and recognition, and (4) in terms of the closeness of the optimum recognition result to the global optimum. When multiple objects are included in the model, the delineation accuracy in terms of TPVF can be improved to 97%-98% with a low FPVF of 0.1%-0.2%. Typically, a

  1. A thermodynamically consistent model of shape-memory alloys

    Czech Academy of Sciences Publication Activity Database

    Benešová, Barbora

    2011-01-01

    Roč. 11, č. 1 (2011), s. 355-356 ISSN 1617-7061 R&D Projects: GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Keywords : slape memory alloys * model based on relaxation * thermomechanic coupling Subject RIV: BA - General Mathematics http://onlinelibrary.wiley.com/doi/10.1002/pamm.201110169/abstract

  2. Building the Nanoplasmonics Toolbox Through Shape Modeling and Single Particle Optical Studies

    Science.gov (United States)

    Ringe, Emilie

    Interest in nanotechnology is driven by unprecedented properties tailorability, achievable by controlling particle structure and composition. Unlike bulk components, minute changes in size and shape affect the optical and electronic properties of nanoparticles. Characterization of such structure-function relationships and better understanding of structure control mechanisms is crucial to the development of applications such as plasmonic sensors and devices. The objective of the current research is thus twofold: to theoretically predict and understand how shape is controlled by synthesis conditions, and to experimentally unravel, through single particle studies, how shape, composition, size, and surrounding environment affect plasmonic properties in noble metal particles. Quantitative, predictive rules and fundamental knowledge obtained from this research contributes to the "nanoplasmonics toolbox", a library designed to provide scientists and engineers the tools to create and optimize novel nanotechnology applications. In this dissertation, single particle approaches are developed and used to unravel the effects of size, shape, substrate, aggregation state and surrounding environment on the optical response of metallic nanoparticles. Ag and Au nanocubes on different substrates are first presented, followed by the discussion of the concept of plasmon length, a universal parameter to describe plasmon energy for a variety of particle shapes and plasmon modes. Plasmonic sensing (both refractive index sensing and surface-enhanced Raman spectroscopy) and polarization effects are then studied at the single particle level. In the last two Chapters, analytical shape models based on the Wulff construction provide unique modeling tools for alloy and kinetically grown nanoparticles. The former reveals a size-dependence of the shape of small alloy particles (such as those used in catalysis) because of surface segregation, while the latter uniquely models the shape of many

  3. Rib-pillar mining at Sigma Colliery

    Energy Technology Data Exchange (ETDEWEB)

    De Beer, J J.S.; Hunter, F; Neethling, A F [Sigma Colliery, Sasolburg (South Africa)

    1991-06-01

    The paper describes the rib-pillar extraction method now used at Sigma Colliery in the Orange Free State. In this method, access roadways (with a high safety factor) are developed into a block of coal suitable for total extraction; pillars that have a low safety factor are then formed and extracted immediately. The method, together with the current practices of labour management, has resulted in better utilization of the coal resources and capital, increased production and labour productivity, and improved safety. 11 figs.

  4. Primary clear cell sarcoma of rib

    International Nuclear Information System (INIS)

    Hersekli, Murat Ali; Ozkoc, Gurkan; Akpinar, Sercan; Ozalay, Metin; Tandogan, Reha N.; Bircan, Sema; Tuncer, Ilhan

    2005-01-01

    Clear cell sarcoma (malignant melanoma of soft tissues) is a very rare soft tissue neoplasm. It generally arises in tendons and aponeuroses. Although metastasis of malignant melanoma to bone is not uncommon, primary clear cell sarcoma of bone is an extremely rare neoplasm. To our knowledge five cases have been reported in the English literature. We present a case of primary clear cell sarcoma of bone in a 28-year-old woman arising in the left ninth rib. We treated the patient with total excision of the mass and postoperative radiotherapy. The patient is alive and well without local recurrence or distant metastasis at 33 months after surgery. (orig.)

  5. Review of Shape Deviation Modeling for Additive Manufacturing

    OpenAIRE

    Zhu , Zuowei; Keimasi , Safa; ANWER , Nabil; Mathieu , Luc; Qiao , Lihong

    2016-01-01

    International audience; Additive Manufacturing (AM) is becoming a promising technology capable of building complex customized parts with internal geometries and graded material by stacking up thin individual layers. However, a comprehensive geometric model for Additive Manufacturing is not mature yet. Dimensional and form accuracy and surface finish are still a bottleneck for AM regarding quality control. In this paper, an up-to-date review is drawn on methods and approaches that have been de...

  6. SIMULATION OF TURBULENT FLOW AND HEAT TRANSFER OVER A BACKWARD -FACING STEP WITH RIBS TURBULATORS

    Directory of Open Access Journals (Sweden)

    Khudheyer S Mushatet

    2011-01-01

    Full Text Available Simulation is presented for a backward facing step flow and heat transfer inside a channel with ribs turbulators. The problem was investigated for Reynolds numbers up to 32000. The effect of a step height, the number of ribs and the rib thickness on the flow and thermal field were investigated. The computed results are presented as streamlines counters, velocity vectors and graphs of Nusselt number and turbulent kinetic energy variation. A control volume method employing a staggered grid techniques was imposed to discretize the governing continuity, full Navier Stockes and energy equations. A computer program using a SIMPLE algorithm was developed to handle the considered problem. The effect of turbulence was modeled by using a k-є model with its wall function formulas. The obtained results show that the strength and size of the re-circulation zones behind the step are increased with the increase of contraction ratio(i.e. with the increase of a step height. The size of recirculation regions and the reattachment length after the ribs are decreased with increasing of the contraction ratio. Also the results show that the Reynolds number and contraction ratio have a significant effect on the variation of turbulent kinetic energy and Nusselt number

  7. Comparison of ultrasonography and radiography in diagnosis of rib fractures.

    Science.gov (United States)

    Pishbin, Elham; Ahmadi, Koorosh; Foogardi, Molood; Salehi, Maryam; Seilanian Toosi, Farrokh; Rahimi-Movaghar, Vafa

    2017-08-01

    Rib fractures are the most common skeletal thoracic injuries resulting from blunt chest trauma. Half of the rib fractures are not detected upon a precise physical evaluation and radiographs. Recently ultrasonography (USG) has been investigated to detect rib fractures. But based on literature the usefulness of USG varies widely. This study was conducted to investigate the role of USG in the detection of possible rib fractures in comparison with radiography. In this cross-sectional study, consecutive patients with minor blunt chest trauma and suspected rib fractures presenting in Imam Reza Hospital located in Mashhad-Iran, between April 2013 and October 2013 were assessed by USG and radiography. The radiography was performed in a posteroanterior (PA) chest projection and oblique rib view centered over the area of trauma. The time duration spent in taking USG and radiography were recorded. The prevalence and location of fractures revealed by USG and radiography were compared. Sixty-one suspected patients were assessed. The male to female ratio was 2.4:1 (43 men and 18 women) with a mean ± SD age of (44.3 ± 19.7) years. There were totally 59 rib fractures in 38 (62.3%) patients based on radiography and USG, while 23 (37.7%) patients had no diagnostic evidence of rib lesions. USG revealed 58 rib fractures in 33 (54.1%) of 61 suspected patients and radiographs revealed 32 rib fractures in 20 (32.8%) of 61 patients. A total of 58 (98.3%) rib fractures were detected by USG, whereas oblique rib view and PA chest radiography showed 27 (45.8%) and 24 (40.7%) rib fractures, respectively. The average duration of USG was (12 ± 3) min (range 7-17 min), whereas the duration of radiography was (27 ± 6) min (range 15-37 min). The kappa coefficient showed a low level of agreement between both USG and PA chest radiography (kappa coefficient = 0.28), and between USG and oblique rib view (kappa coefficient = 0.32). USG discloses more fractures than radiography in

  8. A statistical shape modelling framework to extract 3D shape biomarkers from medical imaging data: assessing arch morphology of repaired coarctation of the aorta

    International Nuclear Information System (INIS)

    Bruse, Jan L.; McLeod, Kristin; Biglino, Giovanni; Ntsinjana, Hopewell N.; Capelli, Claudio

    2016-01-01

    Medical image analysis in clinical practice is commonly carried out on 2D image data, without fully exploiting the detailed 3D anatomical information that is provided by modern non-invasive medical imaging techniques. In this paper, a statistical shape analysis method is presented, which enables the extraction of 3D anatomical shape features from cardiovascular magnetic resonance (CMR) image data, with no need for manual landmarking. The method was applied to repaired aortic coarctation arches that present complex shapes, with the aim of capturing shape features as biomarkers of potential functional relevance. The method is presented from the user-perspective and is evaluated by comparing results with traditional morphometric measurements. Steps required to set up the statistical shape modelling analyses, from pre-processing of the CMR images to parameter setting and strategies to account for size differences and outliers, are described in detail. The anatomical mean shape of 20 aortic arches post-aortic coarctation repair (CoA) was computed based on surface models reconstructed from CMR data. By analysing transformations that deform the mean shape towards each of the individual patient’s anatomy, shape patterns related to differences in body surface area (BSA) and ejection fraction (EF) were extracted. The resulting shape vectors, describing shape features in 3D, were compared with traditionally measured 2D and 3D morphometric parameters. The computed 3D mean shape was close to population mean values of geometric shape descriptors and visually integrated characteristic shape features associated with our population of CoA shapes. After removing size effects due to differences in body surface area (BSA) between patients, distinct 3D shape features of the aortic arch correlated significantly with EF (r = 0.521, p = .022) and were well in agreement with trends as shown by traditional shape descriptors. The suggested method has the potential to discover previously

  9. A statistical shape modelling framework to extract 3D shape biomarkers from medical imaging data: assessing arch morphology of repaired coarctation of the aorta.

    Science.gov (United States)

    Bruse, Jan L; McLeod, Kristin; Biglino, Giovanni; Ntsinjana, Hopewell N; Capelli, Claudio; Hsia, Tain-Yen; Sermesant, Maxime; Pennec, Xavier; Taylor, Andrew M; Schievano, Silvia

    2016-05-31

    Medical image analysis in clinical practice is commonly carried out on 2D image data, without fully exploiting the detailed 3D anatomical information that is provided by modern non-invasive medical imaging techniques. In this paper, a statistical shape analysis method is presented, which enables the extraction of 3D anatomical shape features from cardiovascular magnetic resonance (CMR) image data, with no need for manual landmarking. The method was applied to repaired aortic coarctation arches that present complex shapes, with the aim of capturing shape features as biomarkers of potential functional relevance. The method is presented from the user-perspective and is evaluated by comparing results with traditional morphometric measurements. Steps required to set up the statistical shape modelling analyses, from pre-processing of the CMR images to parameter setting and strategies to account for size differences and outliers, are described in detail. The anatomical mean shape of 20 aortic arches post-aortic coarctation repair (CoA) was computed based on surface models reconstructed from CMR data. By analysing transformations that deform the mean shape towards each of the individual patient's anatomy, shape patterns related to differences in body surface area (BSA) and ejection fraction (EF) were extracted. The resulting shape vectors, describing shape features in 3D, were compared with traditionally measured 2D and 3D morphometric parameters. The computed 3D mean shape was close to population mean values of geometric shape descriptors and visually integrated characteristic shape features associated with our population of CoA shapes. After removing size effects due to differences in body surface area (BSA) between patients, distinct 3D shape features of the aortic arch correlated significantly with EF (r = 0.521, p = .022) and were well in agreement with trends as shown by traditional shape descriptors. The suggested method has the potential to discover

  10. An integrated numerical model for the prediction of Gaussian and billet shapes

    DEFF Research Database (Denmark)

    Hattel, Jesper; Pryds, Nini; Pedersen, Trine Bjerre

    2004-01-01

    Separate models for the atomisation and the deposition stages were recently integrated by the authors to form a unified model describing the entire spray-forming process. In the present paper, the focus is on describing the shape of the deposited material during the spray-forming process, obtained...... by this model. After a short review of the models and their coupling, the important factors which influence the resulting shape, i.e. Gaussian or billet, are addressed. The key parameters, which are utilized to predict the geometry and dimension of the deposited material, are the sticking efficiency...

  11. An approach to modeling tensile–compressive asymmetry for martensitic shape memory alloys

    International Nuclear Information System (INIS)

    Zaki, Wael

    2010-01-01

    In this paper, the asymmetric tensile–compressive behavior of shape memory alloys is modeled based on the mathematical framework of Raniecki and Mróz (2008 Acta Mech. 195 81–102). The framework allows the definition of smooth, non-symmetric, pressure-insensitive yield functions that are used here to incorporate tensile–compressive modeling capabilities into the Zaki–Moumni (ZM) model for shape memory materials. It is found that, despite some increased complexity, the generalized model is capable of producing satisfactory results that agree with uniaxial experimental data taken from the literature

  12. Sparse Principal Component Analysis in Medical Shape Modeling

    DEFF Research Database (Denmark)

    Sjöstrand, Karl; Stegmann, Mikkel Bille; Larsen, Rasmus

    2006-01-01

    Principal component analysis (PCA) is a widely used tool in medical image analysis for data reduction, model building, and data understanding and exploration. While PCA is a holistic approach where each new variable is a linear combination of all original variables, sparse PCA (SPCA) aims...... analysis in medicine. Results for three different data sets are given in relation to standard PCA and sparse PCA by simple thresholding of sufficiently small loadings. Focus is on a recent algorithm for computing sparse principal components, but a review of other approaches is supplied as well. The SPCA...

  13. Modelling of a bridge-shaped nonlinear piezoelectric energy harvester

    International Nuclear Information System (INIS)

    Gafforelli, G; Corigliano, A; Xu, R; Kim, S G

    2013-01-01

    Piezoelectric MicroElectroMechanical Systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvesters

  14. Statistical shape (ASM) and appearance (AAM) models for the segmentation of the cerebellum in fetal ultrasound

    Science.gov (United States)

    Reyes López, Misael; Arámbula Cosío, Fernando

    2017-11-01

    The cerebellum is an important structure to determine the gestational age of the fetus, moreover most of the abnormalities it presents are related to growth disorders. In this work, we present the results of the segmentation of the fetal cerebellum applying statistical shape and appearance models. Both models were tested on ultrasound images of the fetal brain taken from 23 pregnant women, between 18 and 24 gestational weeks. The accuracy results obtained on 11 ultrasound images show a mean Hausdorff distance of 6.08 mm between the manual segmentation and the segmentation using active shape model, and a mean Hausdorff distance of 7.54 mm between the manual segmentation and the segmentation using active appearance model. The reported results demonstrate that the active shape model is more robust in the segmentation of the fetal cerebellum in ultrasound images.

  15. Case report: clinical and postmortem findings in four cows with rib fracture

    OpenAIRE

    Braun, Ueli; Warislohner, Sonja; Hetzel, Udo; Nuss, Karl

    2017-01-01

    BACKGROUND: Published reports of rib fractures in adult cattle are limited to the occurrence of chronic rib swellings caused by calluses, which are unremarkable from a clinical standpoint, whereas studies identifying clinical signs of rib fractures were not found in a literature search. This report describes the clinical and postmortem findings in four cows with rib fractures. CASE PRESENTATION: The 13th rib was fractured in three cows and the 11th rib in the remaining cow; three fractures...

  16. A feed-forward spiking model of shape-coding by IT cells

    Directory of Open Access Journals (Sweden)

    August eRomeo

    2014-05-01

    Full Text Available The ability to recognize a shape is linked to figure-ground organization. Cell preferences appear to be correlated across contrast-polarity reversals and mirror reversals of polygon displays, but not so much across figure-ground (FG reversals. Here we present a network structure which explains both shape-coding by IT cells and the suppression of responses to figure-ground reversed stimuli. In the model figure-ground discrimination is achieved much before shape discrimination, that is itself evidenced by the difference in the spiking onsets of a couple of cells selective for two image categories.

  17. Teaching and Learning of Computational Modelling in Creative Shaping Processes

    Directory of Open Access Journals (Sweden)

    Daniela REIMANN

    2017-10-01

    Full Text Available Today, not only diverse design-related disciplines are required to actively deal with the digitization of information and its potentials and side effects for education processes. In Germany, technology didactics developed in vocational education and computer science education in general education, both separated from media pedagogy as an after-school program. Media education is not a subject in German schools yet. However, in the paper we argue for an interdisciplinary approach to learn about computational modeling in creative processes and aesthetic contexts. It crosses the borders of programming technology, arts and design processes in meaningful contexts. Educational scenarios using smart textile environments are introduced and reflected for project based learning.

  18. Hysteresis modeling of magnetic shape memory alloy actuator based on Krasnosel'skii-Pokrovskii model.

    Science.gov (United States)

    Zhou, Miaolei; Wang, Shoubin; Gao, Wei

    2013-01-01

    As a new type of intelligent material, magnetically shape memory alloy (MSMA) has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP) model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator.

  19. Hysteresis Modeling of Magnetic Shape Memory Alloy Actuator Based on Krasnosel'skii-Pokrovskii Model

    Directory of Open Access Journals (Sweden)

    Miaolei Zhou

    2013-01-01

    Full Text Available As a new type of intelligent material, magnetically shape memory alloy (MSMA has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator.

  20. A Bidirectional Subsurface Remote Sensing Reflectance Model Explicitly Accounting for Particle Backscattering Shapes

    Science.gov (United States)

    He, Shuangyan; Zhang, Xiaodong; Xiong, Yuanheng; Gray, Deric

    2017-11-01

    The subsurface remote sensing reflectance (rrs, sr-1), particularly its bidirectional reflectance distribution function (BRDF), depends fundamentally on the angular shape of the volume scattering functions (VSFs, m-1 sr-1). Recent technological advancement has greatly expanded the collection, and the knowledge of natural variability, of the VSFs of oceanic particles. This allows us to test the Zaneveld's theoretical rrs model that explicitly accounts for particle VSF shapes. We parameterized the rrs model based on HydroLight simulations using 114 VSFs measured in three coastal waters around the United States and in oceanic waters of North Atlantic Ocean. With the absorption coefficient (a), backscattering coefficient (bb), and VSF shape as inputs, the parameterized model is able to predict rrs with a root mean square relative error of ˜4% for solar zenith angles from 0 to 75°, viewing zenith angles from 0 to 60°, and viewing azimuth angles from 0 to 180°. A test with the field data indicates the performance of our model, when using only a and bb as inputs and selecting the VSF shape using bb, is comparable to or slightly better than the currently used models by Morel et al. and Lee et al. Explicitly expressing VSF shapes in rrs modeling has great potential to further constrain the uncertainty in the ocean color studies as our knowledge on the VSFs of natural particles continues to improve. Our study represents a first effort in this direction.

  1. Comparison of Postoperative Pain Relief by Intercostal Block Between Pre-rib Harvest and Post-rib Harvest Groups

    International Nuclear Information System (INIS)

    Bashir, M. M.; Shahzad, M. A.; Yousaf, M. N.; Khan, B. A.; Khan, F. A.

    2014-01-01

    Objective: To compare intercostal nerve block before and after rib harvest in terms of mean postoperative pain score and mean postoperative tramadol usage. Study Design: Randomized controlled trial. Place and Duration of Study: Department of Plastic Surgery, Mayo Hospital, KEMU, Lahore, from January 2011 to July 2012. Methodology: Patients (n = 120) of either gender with ASA class-I and II requiring autogenous costal cartilage graft were inducted. Patients having history of local anaesthetic hypersensitivity and age 60 years were excluded. Subjects were randomly assigned to pre-rib harvest (group-1) and post-rib harvest (group-2). Local anaesthetic mixture was prepared by adding 10 milliliters 2% lidocaine to 10 milliliters 0.5% bupivacaine to obtain a total 20 ml solution. Group-1 received local anaesthetic infiltration along the proposed incision lines and intercostals block before the rib harvest. Group-2 received the infiltration and block after rib harvest. Postoperative consumption of tramadol and pain scores were measured at 6 and 12 hours postoperatively using VAS. Results: Mean age was 31.43 A +- 10.78 years. The mean pain scores at 6 hours postoperatively were 1.033 A +- 0.609 and 2.4667 A +- 0.812 in pre-rib harvest and post-rib harvest groups respectively (p < 0.0001). The mean pain scores at 12 hours postoperatively were 1.45 A +- 0.565 and 3.65 A +- 0.633 in pre-rib harvest and post-rib harvest groups respectively (p < 0.0001). The mean tramadol used postoperatively in first 24 hours was 169 A +- 29.24 mg and 255 A +- 17.70 mg in prerib harvest and post-rib harvest groups respectively (p < 0.0001). Conclusion: Intercostal block administered before rib harvest as preemptive strategy result in decreased postoperative pain scores and narcotic use. (author)

  2. Rib fractures in blunt chest trauma - associated thoracic injuries

    Directory of Open Access Journals (Sweden)

    Iv. Dimitrov

    2017-09-01

    Full Text Available PURPOSE. The aim of our retrospective study was to analyze the patterns of associated thoracic injuries in patients underwent blunt chest trauma and rib fractures. METHODS. The study included 212 patients with rib fractures due to blunt thoracic trauma. The mechanism of trauma, the type of rib fracture and the type of associated injuries were analyzed. RESULTS. The patients were divided in two groups according to the number of fractured ribs-group I included the patients with up to two fractured ribs (72 patients-33,9%, and group II – with ≥3 fractured ribs (140 patients-66,1%. Associated chest injuries were present in 36 of the patients from group I (50%, and in 133 patients from group II (95%. Pulmonary contusion was the most common intrathoracicinjurie-65,6% of the cases. The mean hospital stay was 8, 7 days. The lethality rate was 16,9% -all of them due to the associated chest injuries. CONCLUSIONS. The mortality related to rib fractures is affected by the associated thoracic injuries, the advanced age, and the number of fractured ribs.

  3. Surgical Management of Rib Fractures: Strategies and Literature Review.

    Science.gov (United States)

    de Jong, M B; Kokke, M C; Hietbrink, F; Leenen, L P H

    2014-06-01

    Rib fractures can cause significant problems in trauma patients, often resulting in pain and difficulty with respiration. To prevent pulmonary complications and decrease the morbidity and mortality rates of patients with rib fractures, currently there is a trend to provide surgical management of patients with flail chest. However, the indications for rib fracture fixation require further specification. Past and current strategies are described according to a review of the medical literature. A systematic review was performed including current indications for rib fracture fixation. MEDLINE (2000-2013) was searched, as well as Embase (2000-2013) and Cochrane Databases, using the keywords rib, fracture, fixation, plate, repair, and surgery. Three retrospective studies were found that described different techniques for rib fracture fixation. The results demonstrated a reduced number of ventilation days, decreased long-term morbidity and pain, and satisfactory rehabilitation after surgical treatment. In addition to flail chest, age, Injury Severity Score, and the number of rib fractures were important predictive factors for morbidity and mortality. Surgical rib fracture fixation might be indicated in a broader range of cases than is currently performed. Prospective randomized trials are needed for further confirmation. © The Finnish Surgical Society 2014.

  4. Quality of life after major trauma with multiple rib fractures.

    Science.gov (United States)

    Marasco, Silvana; Lee, Geraldine; Summerhayes, Robyn; Fitzgerald, Mark; Bailey, Michael

    2015-01-01

    Rib fractures are a common injury presenting to major trauma centres and community hospitals. Aside from the acute impact of rib fracture injury, longer-term morbidity of pain, disability and deformity have been described. Despite this, the mainstay of management for the vast majority of rib fracture injuries remains supportive only with analgesia and where required respiratory support. This study aimed to document the long-term quality of life in a cohort of major trauma patients with rib fracture injury over 24 months. Retrospective review (July 2006-July 2011) of 397 major trauma patients admitted to The Alfred Hospital with rib fractures and not treated with operative rib fixation. The main outcome measures were quality of life over 24 months post injury assessed using the Glasgow Outcome Scale Extended and SF12 health assessment forms and a pain questionnaire. Assessment over 24 months of major trauma patients with multiple rib fractures demonstrated significantly lower quality of life compared with published Australian norms at all time points measured. Return to work rates were poor with only 71% of those who were working prior to their accident, returning to any work. This study demonstrates a significant reduction in quality of life for rib fracture patients requiring admission to hospital, which does not return to the level of Australian norms for at least two years. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  5. Rib enlargement in premature infants with bronchopulmonary dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hye Kyung; Han, Kim Bokyung; Chang, Yun Sil; Choo, In Wook [Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul (Korea, Republic of); Kim, Kyeong Ah [Anyang General Hospital, Anyang (Korea, Republic of)

    2000-04-01

    The purpose of this study is to describe the rib changes seen in patients with brochopulmonary dysplasia (BPD). Serial chest radiographs of nine premature infants with BPD who showed diffuse rib enlargement were reviewed for hyperinflation, which was compared with the observed degree of rib enlargement. Vibrator chest physiotherapy was performed in all cases, and five infants underwent conventional ventilation plus high frequency oscillatory ventilation therapy. Their calcium level was normal whereas alkaline phosphatase and phosphate levels were high. In all infants except one, liver enzyme levels were normal. For the treatment of patent ductus arteriosus, infection, and BPD, medications including indomethacin, antibiotics, and dexamethasone were administered. Vitamin D was given to all patients with total parenteral nutrition. Rib enlargement was found to be severe (n=3D4), moderate (n=3D3), or mild (n=3D2) with undulating margins or posterior tapering (n=3D2). Hyperinflation was noted in eight patients, in seven of whom it was moderate to severe. Among these seven, rib enlargement was severe (n=3D2), moderate (n=3D3), or mild (n=3D2). In one infant with mild hyperinflation, rib enlargement was severe. Bilateral irregular infiltrates and atelectases were noted in all patients. In BPD patients, rib enlargement may be seen. In order to differentiate this process from systemic bone disease or bony dysplasia, an awareness of the rib changes occurring in patients with BPD may be important. (author)

  6. The prevalence of cervical ribs in Enugu, Nigeria

    African Journals Online (AJOL)

    2015-11-18

    Nov 18, 2015 ... ... prevalence of cervical ribs and its variation with sex and age among patients ... The patients' identities were removed from the ... syndrome, only 8–10% actually has cervical rib as ... Anatomy, symptoms, diagnosis, and treatment. ... Illinois: American Association of Neurological Surgeons; 1998. p. 157-70.

  7. Rib enlargement in premature infants with bronchopulmonary dysplasia

    International Nuclear Information System (INIS)

    Yoon, Hye Kyung; Han, Kim Bokyung; Chang, Yun Sil; Choo, In Wook; Kim, Kyeong Ah

    2000-01-01

    The purpose of this study is to describe the rib changes seen in patients with brochopulmonary dysplasia (BPD). Serial chest radiographs of nine premature infants with BPD who showed diffuse rib enlargement were reviewed for hyperinflation, which was compared with the observed degree of rib enlargement. Vibrator chest physiotherapy was performed in all cases, and five infants underwent conventional ventilation plus high frequency oscillatory ventilation therapy. Their calcium level was normal whereas alkaline phosphatase and phosphate levels were high. In all infants except one, liver enzyme levels were normal. For the treatment of patent ductus arteriosus, infection, and BPD, medications including indomethacin, antibiotics, and dexamethasone were administered. Vitamin D was given to all patients with total parenteral nutrition. Rib enlargement was found to be severe (n=3D4), moderate (n=3D3), or mild (n=3D2) with undulating margins or posterior tapering (n=3D2). Hyperinflation was noted in eight patients, in seven of whom it was moderate to severe. Among these seven, rib enlargement was severe (n=3D2), moderate (n=3D3), or mild (n=3D2). In one infant with mild hyperinflation, rib enlargement was severe. Bilateral irregular infiltrates and atelectases were noted in all patients. In BPD patients, rib enlargement may be seen. In order to differentiate this process from systemic bone disease or bony dysplasia, an awareness of the rib changes occurring in patients with BPD may be important. (author)

  8. Strength of normal sections of NPP composite monolithic constructions with ribbed reinforced panels

    International Nuclear Information System (INIS)

    Klyashitskij, V.I.; Kirillov, A.P.

    1980-01-01

    Strength characteristics and recommendations on designing composite-monolytic structures of NPP with ribbed reinforced panels are considered. Ribbed reinforced panel consists of a system of cross ribs joined with a comparatively thin (25 mm thick) plate. The investigations were carried on using models representing columns symmetrically reinforced with reinforced panels with a low percent of reinforcing. The monolithic structures consisting of ribbed reinforced panels and cast concrete for making monoliths as well as monolithic having analogous strength characteristics of extended and compressed zones have similar strengths. It is shown that calculation of supporting power of composite-monolithic structures is performed according to techniques developed for monolithic structures. Necessity of structural transverse fittings no longer arises in case of corresponding calculational substitution of stability of compressed parts of fittings. Supporting power of a structure decreases not more than by 10% in the presence of cracks in the reinforced panels of the compressed zone. Application of composite-monolithic structures during the construction of the Kursk, Smolensk and Chernobylskaya NPPs permitted to decrease labour content and reduce periods of accomplishment of these works which saves over 6 million roubles

  9. Surgical stabilization of severe rib fractures decreases incidence of retained hemothorax and empyema.

    Science.gov (United States)

    Majercik, Sarah; Vijayakumar, Sathya; Olsen, Griffin; Wilson, Emily; Gardner, Scott; Granger, Steven R; Van Boerum, Don H; White, Thomas W

    2015-12-01

    Retained hemothorax (RH) is relatively common after chest trauma and can lead to empyema. We hypothesized that patients who have surgical fixation of rib fractures (SSRF) have less RH and empyema than those who have medical management of rib fractures (MMRF). Admitted rib fracture patients from January 2009 to June 2013 were identified. A 2:1 propensity score model identified MMRF patients who were similar to SSRF. RH, and empyema and readmissions, were recorded. Variables were compared using Fisher exact test and Wilcoxon rank-sum tests. One hundred thirty-seven SSRF and 274 MMRF were analyzed; 31 (7.5%) had RH requiring 35 interventions; 3 (2.2%) SSRF patients had RH compared with 28 (10.2%) MMRF (P = .003). Four (14.3%) MMRF subjects with RH developed empyema versus zero in the SSRF group (P = .008); 6 (19.3%) RH patients required readmission versus 14 (3.7%) in the non-RH group (P = .002). Patients with rib fractures who have SSRF have less RH compared with similar MMRF patients. Although not a singular reason to perform SSRF, this clinical benefit should not be overlooked. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Investigation into the heat transfer performance of helically ribbed surfaces

    International Nuclear Information System (INIS)

    Firth, R.J.

    1981-12-01

    The first part of an investigation into flow and heat transfer in annular channels and seven pin clusters is described. One of the main aims of the project is to improve cluster heat transfer prediction codes for helically ribbed surfaces. A study is made of the heat transfer and flow characteristics of a helically ribbed pin in an annular channel. It is shown that the swirling flow, which is induced by the helical ribs, gives rise to substantially enhanced diffusivity levels. This phenomenon had not been taken into account by previous analysis techniques. The methods for analysing heat transfer and pressure drop data from annular channels which were originally developed for non-swirling flow are generalised to accommodate swirling flow. The new methods are shown to be consistent with empirical data. Roughness parameter data is presented for helically ribbed surfaces with an axial rib pitch into height ratio of about 7. (author)

  11. Interactive Shape Modeling using a Skeleton-Mesh Co-Representation

    DEFF Research Database (Denmark)

    Bærentzen, Jacob Andreas; Abdrashitov, Rinat; Singh, Karan

    2014-01-01

    We introduce the Polar-Annular Mesh representation (PAM). A PAM is a mesh-skeleton co-representation designed for the modeling of 3D organic, articulated shapes. A PAM represents a manifold mesh as a partition of polar (triangle fans) and annular (rings of quads) regions. The skeletal topology of...... a PAM to a quad-only mesh. We further present a PAM-based multi-touch sculpting application in order to demonstrate its utility as a shape representation for the interactive modeling of organic, articulated figures as well as for editing and posing of pre-existing models....

  12. A Minimal Path Searching Approach for Active Shape Model (ASM)-based Segmentation of the Lung.

    Science.gov (United States)

    Guo, Shengwen; Fei, Baowei

    2009-03-27

    We are developing a minimal path searching method for active shape model (ASM)-based segmentation for detection of lung boundaries on digital radiographs. With the conventional ASM method, the position and shape parameters of the model points are iteratively refined and the target points are updated by the least Mahalanobis distance criterion. We propose an improved searching strategy that extends the searching points in a fan-shape region instead of along the normal direction. A minimal path (MP) deformable model is applied to drive the searching procedure. A statistical shape prior model is incorporated into the segmentation. In order to keep the smoothness of the shape, a smooth constraint is employed to the deformable model. To quantitatively assess the ASM-MP segmentation, we compare the automatic segmentation with manual segmentation for 72 lung digitized radiographs. The distance error between the ASM-MP and manual segmentation is 1.75 ± 0.33 pixels, while the error is 1.99 ± 0.45 pixels for the ASM. Our results demonstrate that our ASM-MP method can accurately segment the lung on digital radiographs.

  13. A minimal path searching approach for active shape model (ASM)-based segmentation of the lung

    Science.gov (United States)

    Guo, Shengwen; Fei, Baowei

    2009-02-01

    We are developing a minimal path searching method for active shape model (ASM)-based segmentation for detection of lung boundaries on digital radiographs. With the conventional ASM method, the position and shape parameters of the model points are iteratively refined and the target points are updated by the least Mahalanobis distance criterion. We propose an improved searching strategy that extends the searching points in a fan-shape region instead of along the normal direction. A minimal path (MP) deformable model is applied to drive the searching procedure. A statistical shape prior model is incorporated into the segmentation. In order to keep the smoothness of the shape, a smooth constraint is employed to the deformable model. To quantitatively assess the ASM-MP segmentation, we compare the automatic segmentation with manual segmentation for 72 lung digitized radiographs. The distance error between the ASM-MP and manual segmentation is 1.75 +/- 0.33 pixels, while the error is 1.99 +/- 0.45 pixels for the ASM. Our results demonstrate that our ASM-MP method can accurately segment the lung on digital radiographs.

  14. Experimental investigation of cross-over jets in a rib-roughened trailing-edge cooling channel

    Science.gov (United States)

    Xue, Fei

    Increasing the rotor inlet temperature can dramatically increase the efficiency and power output of the gas turbine engine. However, the melting point of turbine blade material limits the realistic upper bound of the rotor inlet temperature. As a result, the development of high temperature turbine blade material and advanced turbine blade cooling technology determines the future of turbine blade engine. Adding impingement jet holes and rib turbulators in the inner cooling channel of the gas turbine blades are two effective ways to enhance the cooling effects. The purpose of this study is to figure out the influence of different combinations of jet holes and rib turbulators on the heat transfer efficiency. A tabletop scale test model is used in the study to simulate the cooling cavity of trailing edge and its feed channel in a real gas turbine blade. The Dimensional Analysis Theory is used in the study to eliminate the influence of scaling. Two different crossover slots are tested with 5 different rib arrangements, and each of the test geometries is tested for 6 jet Reynolds numbers ranging from 10,000 to 36,000. The two different crossover slots are the crossover slots with 0 and 5 degree tilt angles. The four different rib arrangements are ribs with 0 degree, 45 degree, 90 degree and 135 degree angles of attack with respect to the flow direction. Furthermore, a smooth test section (no ribs) was also tested. The steady state liquid crystal thermography is used to quantify the heat transfer performance of the target areas. The variation of Nusselt number versus Reynolds number is plotted for each of the 10 geometries. Also, the variation of Nusselt number versus Reynolds number are compared for different rib angles of attack with the same crossover slot tilt angle, and between different crossover slots tilt angles with the same rib angle. The results show that, the area-weighted average Nusselt number increases monotonically with the Reynolds number; the target

  15. On the selection of shape and orientation of a greenhouse. Thermal modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Sethi, V.P. [Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana 141 004, Punjab (India)

    2009-01-15

    In this study, five most commonly used single span shapes of greenhouses viz. even-span, uneven-span, vinery, modified arch and quonset type have been selected for comparison. The length, width and height (at the center) are kept same for all the selected shapes. A mathematical model for computing transmitted total solar radiation (beam, diffused and ground reflected) at each hour, for each month and at any latitude for the selected geometry greenhouses (through each wall, inclined surfaces and roofs) is developed for both east-west and north-south orientation. Computed transmitted solar radiation is then introduced in a transient thermal model developed to compute hourly inside air temperature for each shape and orientation. Experimental validation of both the models is carried out for the measured total solar radiation and inside air temperature for an east-west orientation, even-span greenhouse (for a typical day in summer) at Ludhiana (31 N and 77 E) Punjab, India. During the experimentation, capsicum crop is grown inside the greenhouse. The predicted and measured values are in close agreement. Results show that uneven-span shape greenhouse receives the maximum and quonset shape receives the minimum solar radiation during each month of the year at all latitudes. East-west orientation is the best suited for year round greenhouse applications at all latitudes as this orientation receives greater total radiation in winter and less in summer except near the equator. Results also show that inside air temperature rise depends upon the shape of the greenhouse and this variation from uneven-span shape to quonset shape is 4.6 C (maximum) and 3.5 C (daily average) at 31 N latitude. (author)

  16. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    Science.gov (United States)

    Osborn, Jeffrey W

    2008-12-07

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops.

  17. Detecting Growth Shape Misspecifications in Latent Growth Models: An Evaluation of Fit Indexes

    Science.gov (United States)

    Leite, Walter L.; Stapleton, Laura M.

    2011-01-01

    In this study, the authors compared the likelihood ratio test and fit indexes for detection of misspecifications of growth shape in latent growth models through a simulation study and a graphical analysis. They found that the likelihood ratio test, MFI, and root mean square error of approximation performed best for detecting model misspecification…

  18. A model to simulate day-to-day variations in rectum shape

    NARCIS (Netherlands)

    Hoogeman, Mischa S.; van Herk, Marcel; Yan, Di; Boersma, Liesbeth J.; Koper, Peter C. M.; Lebesque, Joos V.

    2002-01-01

    PURPOSE: To develop a model that predicts possible rectum configurations that can occur during radiotherapy of prostate cancer on the basis of a planning CT scan and patient group data. MATERIALS AND METHODS: We used a stochastic shape description model with a limited number of parameters (area,

  19. Painful rib hump: a new clinical sign for detecting intraspinal rib displacement in scoliosis due to neurofibromatosis

    Directory of Open Access Journals (Sweden)

    Katsalouli Marina

    2006-06-01

    Full Text Available Abstract Background Spinal cord compression and associate neurological impairment is rare in patients with scoliosis and neurofibromatosis. Common reasons are vertebral subluxation, dislocation, angulation and tumorous lesions around the spinal canal. Only twelve cases of intraspinal rib dislocation have been reported in the literature. The aim of this report is to present a case of rib penetration through neural foramen at the apex of a scoliotic curve in neurofibromatosis and to introduce a new clinical sign for its detection. Methods A 13-year-old girl was evaluated for progressive left thoracic kyphoscoliotic curve due to a type I neurofibromatosis. Clinical examination revealed multiple large thoracic and abdominal "cafe-au-lait" spots, neurological impairment of the lower limbs and the presence of a thoracic gibbous that was painful to pressure at the level of the left eighth rib (Painful Rib Hump. CT-scan showed detachment and translocation of the cephalic end of the left eighth rib into the adjacent enlarged neural foramen. The M.R.I. examination of the spine showed neither cord abnormality nor neurogenic tumor. Results The patient underwent resection of the intraspinal mobile eighth rib head and posterior spinal instrumentation and was neurologically fully recovered six months postoperatively. Conclusion Spine surgeons should be aware of intraspinal rib displacement in scoliotic curves in neurofibromatosis. Painful rib hump is a valuable diagnostic tool for this rare clinical entity.

  20. Experimental and modelling studies of the shape memory properties of amorphous polymer network composites

    International Nuclear Information System (INIS)

    Arrieta, J S; Diani, J; Gilormini, P

    2014-01-01

    Shape memory polymer composites (SMPCs) have become an important way to leverage improvements in the development of applications featuring shape memory polymers (SMPs). In this study, an amorphous SMP matrix has been filled with different types of reinforcements. An experimental set of results is presented and then compared to three-dimensional (3D) finite-element simulations. Thermomechanical shape memory cycles were performed in uniaxial tension. The fillers effect was studied in stress-free and constrained-strain recoveries. Experimental observations indicate complete shape recovery and put in evidence the increased sensitivity of constrained length stress recoveries to the heating ramp on the tested composites. The simulations reproduced a simplified periodic reinforced composite and used a model for the matrix material that has been previously tested on regular SMPs. The latter combines viscoelasticity at finite strain and time-temperature superposition. The simulations easily allow representation of the recovery properties of a reinforced SMP. (paper)

  1. Quantification of localized vertebral deformities using a sparse wavelet-based shape model.

    Science.gov (United States)

    Zewail, R; Elsafi, A; Durdle, N

    2008-01-01

    Medical experts often examine hundreds of spine x-ray images to determine existence of various pathologies. Common pathologies of interest are anterior osteophites, disc space narrowing, and wedging. By careful inspection of the outline shapes of the vertebral bodies, experts are able to identify and assess vertebral abnormalities with respect to the pathology under investigation. In this paper, we present a novel method for quantification of vertebral deformation using a sparse shape model. Using wavelets and Independent component analysis (ICA), we construct a sparse shape model that benefits from the approximation power of wavelets and the capability of ICA to capture higher order statistics in wavelet space. The new model is able to capture localized pathology-related shape deformations, hence it allows for quantification of vertebral shape variations. We investigate the capability of the model to predict localized pathology related deformations. Next, using support-vector machines, we demonstrate the diagnostic capabilities of the method through the discrimination of anterior osteophites in lumbar vertebrae. Experiments were conducted using a set of 150 contours from digital x-ray images of lumbar spine. Each vertebra is labeled as normal or abnormal. Results reported in this work focus on anterior osteophites as the pathology of interest.

  2. Constitutive model for a stress- and thermal-induced phase transition in a shape memory polymer

    International Nuclear Information System (INIS)

    Guo, Xiaogang; Liu, Liwu; Liu, Yanju; Zhou, Bo; Leng, Jinsong

    2014-01-01

    Recently, increasing applications of shape memory polymers have pushed forward the development of appropriate constitutive models for smart materials such as the shape memory polymer. During the heating process, the phase transition, which is a continuous time-dependent process, happens in the shape memory polymer, and various individual phases will form at different configuration temperatures. In addition, these phases can generally be divided into two parts: the frozen and active phase (Liu Y et al 2006 Int. J. Plast. 22 279–313). During the heating or cooling process, the strain will be stored or released with the occurring phase transition between these two parts. Therefore, a shape memory effect emerges. In this paper, a new type of model was developed to characterize the variation of the volume fraction in a shape memory polymer during the phase transition. In addition to the temperature variation, the applied stress was also taken as a significant influence factor on the phase transition. Based on the experimental results, an exponential equation was proposed to describe the relationship between the stress and phase transition temperature. For the sake of describing the mechanical behaviors of the shape memory polymer, a three-dimensional constitutive model was established. Also, the storage strain, which was the key factor of the shape memory effect, was also discussed in detail. Similar to previous works, we first explored the effect of applied stress on storage strain. Through comparisons with the DMA and the creep experimental results, the rationality and accuracy of the new phase transition and constitutive model were finally verified. (paper)

  3. Comparative study between rib imaging of DR dual energy subtraction technology and chest imaging

    International Nuclear Information System (INIS)

    Yu Jianming; Lei Ziqiao; Kong Xiangchuang

    2006-01-01

    Objective: To investigate the application value of DR dual energy subtraction technology in rib lesions. Methods: 200 patients were performed with chest DR dual energy subtraction, comparing the rib imaging between DR of thorax and chest imaging using ROC analysis. Results: Among the total of 200 patients, there are 50 cases of rib calcification, 7 cases of rib destruction, 22 cases of rib fracture. The calcification, destruction and fracture were displayed respectively by ribs below diaphragm and rib markings. The analytic parameter of rib imaging of DR dual energy subtraction Az is 0.9367, while that of rib imaging of chest Az is 0.6830. Conclusion: DR dual energy subtraction technology is superior to chest imaging in the displaying of rib lesion and ribs below diaphragm. (authors)

  4. Data Qualification Report For DTN: MO0012RIB00065.002, Parameter Values For Transfer Coefficients

    International Nuclear Information System (INIS)

    C.H. Tung

    2001-01-01

    A data-qualification evaluation was conducted on Reference Information Base (RIB) data set MOO0 12RIB00065.002, ''Parameter Values for Transfer Coefficients''. The corroborating data method was used to evaluate the data. This method was selected because it closely matches the literature-review method followed to select parameter values. Five criteria were considered when the corroborating method was used: adequacy of the corroborative literature, sufficiency of value-selection criteria, implementation of the selection criteria, documentation of the process, and whether the analysis was conducted in accordance with applicable quality assurance (QA) procedures. Three criteria were used when a literature review was not conducted: appropriate logic used to select parameters, documentation of the process, and whether the analysis was conducted in accordance with applicable QA procedures. The RIB data item, the associated Analysis and Model Report (AMR), the corroborative literature, and the results of an audit revision O/ICN--0 of the AMR were examined. All calculations and the selection process for all values were repeated and confirmed. The qualification team concluded: (1) A sufficient quantity of corroborative literature was reviewed and no additional literature was identified that should have been considered. (2) The selection criteria were sufficient and resulted in valid parameter values. (3) The process was well defined, adequately documented in the AMR, and correctly followed. (4) The analysis was developed in accordance with applicable QA procedures. No negative findings were documented that resulted in questions about the quality of the data. The qualification team therefore recommends that the qualification status of RIB data set MO0012RIB00065.002 be changed to qualified

  5. Surface tension and Wulff shape for a lattice model without spin flip symmetry.

    CERN Document Server

    Bodineau, T

    2003-01-01

    We propose a new definition of surface tension and check it in a spin model of the Pirogov-Sinai class where the spin flip symmetry is broken. We study the model at low temperatures on the phase transitions line and prove: (i) existence of the surface tension in the thermodynamic limit, for any orientation of the surface and in all dimensions $d\\ge 2$; (ii) the Wulff shape constructed with such a surface tension coincides with the equilibrium shape of the cluster which appears when fixing the total spin magnetization (Wulff problem).

  6. Shape interior modeling and mass property optimization using ray-reps

    DEFF Research Database (Denmark)

    Wu, Jun; Kramer, Lou; Westermann, Rüdiger

    2016-01-01

    , and prove this parametrization covers the optimal interior regarding static and rotational stability criteria. This compact formulation thoroughly reduces the number of design variables compared to the general volumetric element-wise formulation. We demonstrate the effectiveness of our reduced formulation......We present a novel method for the modeling and optimization of the material distribution inside 3D shapes, such that their 3D printed replicas satisfy prescribed constraints regarding mass properties. In particular, we introduce an extension of ray-representation to shape interior modeling...

  7. Instability of the hedgehog shape for the octet baryon in the chiral quark soliton model

    OpenAIRE

    Akiyama, Satoru; Futami, Yasuhiko

    2003-01-01

    In this paper the stability of the hedgehog shape of the chiral soliton is studied for the octet baryon with the SU(3) chiral quark soliton model. The strangeness degrees of freedom are treated by a simplified bound-state approach, which omits the locality of the kaon wave function. The mean field approximation for the flavor rotation is applied to the model. The classical soliton changes shape according to the strangeness. The baryon appears as a rotational band of the combined system of the...

  8. Automatic generation of 3D statistical shape models with optimal landmark distributions.

    Science.gov (United States)

    Heimann, T; Wolf, I; Meinzer, H-P

    2007-01-01

    To point out the problem of non-uniform landmark placement in statistical shape modeling, to present an improved method for generating landmarks in the 3D case and to propose an unbiased evaluation metric to determine model quality. Our approach minimizes a cost function based on the minimum description length (MDL) of the shape model to optimize landmark correspondences over the training set. In addition to the standard technique, we employ an extended remeshing method to change the landmark distribution without losing correspondences, thus ensuring a uniform distribution over all training samples. To break the dependency of the established evaluation measures generalization and specificity from the landmark distribution, we change the internal metric from landmark distance to volumetric overlap. Redistributing landmarks to an equally spaced distribution during the model construction phase improves the quality of the resulting models significantly if the shapes feature prominent bulges or other complex geometry. The distribution of landmarks on the training shapes is -- beyond the correspondence issue -- a crucial point in model construction.

  9. Modeling the modified drug release from curved shape drug delivery systems - Dome Matrix®.

    Science.gov (United States)

    Caccavo, D; Barba, A A; d'Amore, M; De Piano, R; Lamberti, G; Rossi, A; Colombo, P

    2017-12-01

    The controlled drug release from hydrogel-based drug delivery systems is a topic of large interest for research in pharmacology. The mathematical modeling of the behavior of these systems is a tool of emerging relevance, since the simulations can be of use in the design of novel systems, in particular for complex shaped tablets. In this work a model, previously developed, was applied to complex-shaped oral drug delivery systems based on hydrogels (Dome Matrix®). Furthermore, the model was successfully adopted in the description of drug release from partially accessible Dome Matrix® systems (systems with some surfaces coated). In these simulations, the erosion rate was used asa fitting parameter, and its dependence upon the surface area/volume ratio and upon the local fluid dynamics was discussed. The model parameters were determined by comparison with the drug release profile from a cylindrical tablet, then the model was successfully used for the prediction of the drug release from a Dome Matrix® system, for simple module configuration and for module assembled (void and piled) configurations. It was also demonstrated that, given the same initial S/V ratio, the drug release is independent upon the shape of the tablets but it is only influenced by the S/V evolution. The model reveals itself able to describe the observed phenomena, and thus it can be of use for the design of oral drug delivery systems, even if complex shaped. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Radiation Induced Rib Fractures on Bone Scan after Breast Cancer Surgery and Radiation Therapy

    International Nuclear Information System (INIS)

    Kim, Hae Won; Won, Kyoung Sook; Zeon, Seok Kil; Kim, Jin Hee

    2009-01-01

    This study is to evaluate rib fractures on bone scan in breast cancer patients treated with breast cancer surgery and radiation therapy and to evaluate its relation with radiation therapy and operation modality. Two hundred seventy cases that underwent serial bone scan after breast cancer surgery and radiation therapy were enrolled. Bone scan and chest CT findings of rib fracture were analyzed. The rib uptake was seen in 74 of 270 cases (27.4%) on bone scan and 50 cases (18.5%) were confirmed to have rib fracture by chest CT. The rate of modified radical mastectomy in patients with rib fracture was significantly higher than that in patients without rib fracture (66.0% vs. 27.0%, p=0.000). The rate of additional radiation therapy to axillar or supraclavicular regions in patients with rib fracture was significantly higher than that in patients without rib fracture (62.0% vs. 28.6%, p=0.000). Rib fracture was seen most frequently at 1-2 years after radiation therapy (51.9%) and single rib fracture was seen most frequently (55.2%). Of total 106 rib fractures, focal rib uptake was seen in 94 ribs (88.7%) and diffuse rib uptake was seen in 12 ribs (11.3%). On one year follow-up bone scan, complete resolution of rib uptake was seen in 15 ribs (14.2%). On chest CT, the rate of fracture line in ribs with intense uptake was significantly higher than that in ribs with mild or moderate uptake (p=0.000). The rate of presence of fracture line in ribs with focal uptake was significantly higher than that in ribs with diffuse uptake (p=0.001). Rib fracture in breast cancer patients after radiation therapy was related to radiation portal and operation modality. It should be interpreted carefully as a differential diagnosis of bone metastasis

  11. Radiation Induced Rib Fractures on Bone Scan after Breast Cancer Surgery and Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Won; Won, Kyoung Sook; Zeon, Seok Kil; Kim, Jin Hee [Keimyung University, School of Medicine, Daegu (Korea, Republic of)

    2009-08-15

    This study is to evaluate rib fractures on bone scan in breast cancer patients treated with breast cancer surgery and radiation therapy and to evaluate its relation with radiation therapy and operation modality. Two hundred seventy cases that underwent serial bone scan after breast cancer surgery and radiation therapy were enrolled. Bone scan and chest CT findings of rib fracture were analyzed. The rib uptake was seen in 74 of 270 cases (27.4%) on bone scan and 50 cases (18.5%) were confirmed to have rib fracture by chest CT. The rate of modified radical mastectomy in patients with rib fracture was significantly higher than that in patients without rib fracture (66.0% vs. 27.0%, p=0.000). The rate of additional radiation therapy to axillar or supraclavicular regions in patients with rib fracture was significantly higher than that in patients without rib fracture (62.0% vs. 28.6%, p=0.000). Rib fracture was seen most frequently at 1-2 years after radiation therapy (51.9%) and single rib fracture was seen most frequently (55.2%). Of total 106 rib fractures, focal rib uptake was seen in 94 ribs (88.7%) and diffuse rib uptake was seen in 12 ribs (11.3%). On one year follow-up bone scan, complete resolution of rib uptake was seen in 15 ribs (14.2%). On chest CT, the rate of fracture line in ribs with intense uptake was significantly higher than that in ribs with mild or moderate uptake (p=0.000). The rate of presence of fracture line in ribs with focal uptake was significantly higher than that in ribs with diffuse uptake (p=0.001). Rib fracture in breast cancer patients after radiation therapy was related to radiation portal and operation modality. It should be interpreted carefully as a differential diagnosis of bone metastasis.

  12. What Accounts for Rib Fractures in Older Adults?

    Directory of Open Access Journals (Sweden)

    Lisa-Ann Wuermser

    2011-01-01

    Full Text Available To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21–93 years was followed in a long-term prospective study. Bone mineral density (BMD was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years, 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes.

  13. What Accounts for Rib Fractures in Older Adults?

    Science.gov (United States)

    Wuermser, Lisa-Ann; Achenbach, Sara J.; Amin, Shreyasee; Khosla, Sundeep; Melton, L. Joseph

    2011-01-01

    To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21–93 years was followed in a long-term prospective study. Bone mineral density (BMD) was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years), 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes. PMID:22028986

  14. What accounts for rib fractures in older adults?

    Science.gov (United States)

    Wuermser, Lisa-Ann; Achenbach, Sara J; Amin, Shreyasee; Khosla, Sundeep; Melton, L Joseph

    2011-01-01

    To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21-93 years was followed in a long-term prospective study. Bone mineral density (BMD) was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years), 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes.

  15. [Analysis of 163 rib fractures by imaging examination].

    Science.gov (United States)

    Song, Tian-fu; Wang, Chao-chao

    2014-12-01

    To explore the applications of imaging examination on rib fracture sites in forensic identification. Features including the sites, numbers of the processed imaging examination and the first radiological technology at diagnosis in 56 cases of rib fractures from 163 injuries were retrospectively analyzed. The detection rate of the rib fractures within 14 days was 65.6%. The initial detection rate of anterior rib fracture proceeded by X-ray was 76.2%, then 90.5% detected at a second time X-ray, while the detection rate of CT was 66.7% and 80.0%, respectively. The initial detec- tion rate of rib fracture in axillary section proceeded by X-ray was 27.6%, then 58.6% detected at a second time X-ray, while the detection rate of CT was 54.3% and 80.4%, respectively. The initial detection rate of posterior rib fracture proceeded by X-ray was 63.6%, then 81.8% detected at a second time X-ray, while the detection rate of CT was 50.0% and 70.0%, respectively. It is important to pay attention to the use of combined imaging examinations and the follow-up results. In the cases of suspicious for rib fracture in axillary section, CT examination is suggested in such false X-ray negative cases.

  16. Measurement of local void fraction in a ribbed annulus

    International Nuclear Information System (INIS)

    Steimke, J.L.

    1992-01-01

    The computer code FLOWTRAN-TF is used to analyze hypothetical hydraulic accidents for the nuclear reactor at the Savannah River Site. During a hypothetical Large Break Loss-of-Coolant Accident (LOCA), reactor assemblies would contain a two-phase mixture of air and water which flows downward. Reactor assemblies consist of nested, ribbed annuli. Longitudinal ribs divide each annulus into four subchannels. For accident conditions, air and water can flow past ribs from one subchannel to another. For FLOWTRAN-TF to compute the size of those flows, it is necessary to know the local void fraction in the region of the rib. Measurements have previously been made of length-average void fraction in a ribbed annulus. However, no direct measurements were available of local void fraction. Due to the lack of data, a test was designed to measure local void fraction at the rib. One question addressed by the test was whether void fraction at the rib is solely a function of azimuthal-average void fraction or a function of additional variables such as pressure boundary conditions. This report provides a discussion of this test

  17. Approximate Mathematical Modeling of Osmotic Dehydration of Cone-Shaped Fruits and Vegetables in Hypertonic Solutions

    OpenAIRE

    Mohammad Sirousazar

    2017-01-01

    Water loss kinetics in osmotic dehydration of cone-shaped fruits and vegetables was modeled on the basis of diffusion mechanism, using the Fick’s second law. The model was developed by taking into account the influences of the fruit geometrical characteristics, initial water content of fruit, water diffusion coefficient in fruit, and the water concentration in hypertonic solution. Based on the obtained model, it was shown that the water diffusion coefficient and the initial water concentratio...

  18. Dynamic model updating based on strain mode shape and natural frequency using hybrid pattern search technique

    Science.gov (United States)

    Guo, Ning; Yang, Zhichun; Wang, Le; Ouyang, Yan; Zhang, Xinping

    2018-05-01

    Aiming at providing a precise dynamic structural finite element (FE) model for dynamic strength evaluation in addition to dynamic analysis. A dynamic FE model updating method is presented to correct the uncertain parameters of the FE model of a structure using strain mode shapes and natural frequencies. The strain mode shape, which is sensitive to local changes in structure, is used instead of the displacement mode for enhancing model updating. The coordinate strain modal assurance criterion is developed to evaluate the correlation level at each coordinate over the experimental and the analytical strain mode shapes. Moreover, the natural frequencies which provide the global information of the structure are used to guarantee the accuracy of modal properties of the global model. Then, the weighted summation of the natural frequency residual and the coordinate strain modal assurance criterion residual is used as the objective function in the proposed dynamic FE model updating procedure. The hybrid genetic/pattern-search optimization algorithm is adopted to perform the dynamic FE model updating procedure. Numerical simulation and model updating experiment for a clamped-clamped beam are performed to validate the feasibility and effectiveness of the present method. The results show that the proposed method can be used to update the uncertain parameters with good robustness. And the updated dynamic FE model of the beam structure, which can correctly predict both the natural frequencies and the local dynamic strains, is reliable for the following dynamic analysis and dynamic strength evaluation.

  19. Combining thermodynamic principles with Preisach models for superelastic shape memory alloy wires

    International Nuclear Information System (INIS)

    Doraiswamy, S; Rao, A; Srinivasa, A R

    2011-01-01

    We present a simple model for simulating the response of a superelastic shape memory alloy wire based on the thermodynamics of irreversible processes, which can simulate the full thermomechanical response including internal hysteresis loops, at different temperatures, with minimal data input. The key idea is to separate the dissipative response and the elastic response of shape memory alloys using a Gibbs potential based formulation, and then use a Preisach model for the dissipative part of the response. This enables better handling of the features observed in the superelastic response such as those due to changes in temperature and internal hysteresis loops. We compare the predicted response with experiments performed on 0.75 mm NiTi shape memory alloy wires at three different temperatures

  20. An integrative model of evolutionary covariance: a symposium on body shape in fishes.

    Science.gov (United States)

    Walker, Jeffrey A

    2010-12-01

    A major direction of current and future biological research is to understand how multiple, interacting functional systems coordinate in producing a body that works. This understanding is complicated by the fact that organisms need to work well in multiple environments, with both predictable and unpredictable environmental perturbations. Furthermore, organismal design reflects a history of past environments and not a plan for future environments. How complex, interacting functional systems evolve, then, is a truly grand challenge. In accepting the challenge, an integrative model of evolutionary covariance is developed. The model combines quantitative genetics, functional morphology/physiology, and functional ecology. The model is used to convene scientists ranging from geneticists, to physiologists, to ecologists, to engineers to facilitate the emergence of body shape in fishes as a model system for understanding how complex, interacting functional systems develop and evolve. Body shape of fish is a complex morphology that (1) results from many developmental paths and (2) functions in many different behaviors. Understanding the coordination and evolution of the many paths from genes to body shape, body shape to function, and function to a working fish body in a dynamic environment is now possible given new technologies from genetics to engineering and new theoretical models that integrate the different levels of biological organization (from genes to ecology).

  1. Modified rib pivot lateral thoracotomy: a case series.

    Science.gov (United States)

    Appelgrein, C; Hosgood, G

    2018-01-01

    To describe a modified rib pivot thoracotomy and its clinical application in client-owned dogs and cats. Case series of 24 dogs and 1 cat requiring a thoracotomy. A lateral thoracic incision over the required thoracic segment was made. The latissimus dorsi muscle was reflected dorsally. The predetermined rib was identified and the periosteum overlying the rib was elevated circumferentially, avoiding the intercostal neurovascular structures. Holes were pre-placed above and below the proposed osteotomy site. The rib was osteotomised and pivoted cranially. The pleura was incised and the required intrathoracic procedure was then performed. The thoracic cavity was closed by pre-placement of a suture through the pre-placed holes within the osteotomised rib. The pleura and intercostal musculature were closed, avoiding the intercostal neurovascular structures. The rib was re-apposed and the lateral approach was closed. The cases included were reviewed for both the rib pivoted as per the procedure required and postoperative complications. The study group comprised 8 Staffordshire Bull Terriers, 2 Poodles, 2 German Shepherd Dogs, 1 each of Basset Hound, Rhodesian Ridgeback, Golden Retriever, Australian Shepherd, Vizsla, Bull Mastiff, Schnauzer, Jack Russell Terrier, Bulldog, Deerhound, Labrador Retriever and Australian Terrier, and 1 cat. A modified rib pivot thoracotomy was performed for lung lobectomy (n = 11), oesophagectomy (7), subtotal pericardectomy (5), patent ductus arteriosus ligation (1) and thoracic duct ligation (1). Follow-up ranged from 2 to 40 weeks postoperatively. Postoperative complications included seroma formation in two dogs. A modified rib pivot thoracotomy should be considered as an alternative lateral thoracic approach with good exposure, minimal complications and low morbidity. © 2018 Australian Veterinary Association.

  2. DNA sequence+shape kernel enables alignment-free modeling of transcription factor binding.

    Science.gov (United States)

    Ma, Wenxiu; Yang, Lin; Rohs, Remo; Noble, William Stafford

    2017-10-01

    Transcription factors (TFs) bind to specific DNA sequence motifs. Several lines of evidence suggest that TF-DNA binding is mediated in part by properties of the local DNA shape: the width of the minor groove, the relative orientations of adjacent base pairs, etc. Several methods have been developed to jointly account for DNA sequence and shape properties in predicting TF binding affinity. However, a limitation of these methods is that they typically require a training set of aligned TF binding sites. We describe a sequence + shape kernel that leverages DNA sequence and shape information to better understand protein-DNA binding preference and affinity. This kernel extends an existing class of k-mer based sequence kernels, based on the recently described di-mismatch kernel. Using three in vitro benchmark datasets, derived from universal protein binding microarrays (uPBMs), genomic context PBMs (gcPBMs) and SELEX-seq data, we demonstrate that incorporating DNA shape information improves our ability to predict protein-DNA binding affinity. In particular, we observe that (i) the k-spectrum + shape model performs better than the classical k-spectrum kernel, particularly for small k values; (ii) the di-mismatch kernel performs better than the k-mer kernel, for larger k; and (iii) the di-mismatch + shape kernel performs better than the di-mismatch kernel for intermediate k values. The software is available at https://bitbucket.org/wenxiu/sequence-shape.git. rohs@usc.edu or william-noble@uw.edu. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

  3. Computer-aided-design-model-assisted absolute three-dimensional shape measurement.

    Science.gov (United States)

    Li, Beiwen; Bell, Tyler; Zhang, Song

    2017-08-20

    Conventional three-dimensional (3D) shape measurement methods are typically generic to all types of objects. Yet, for many measurement conditions, such a level of generality is inessential when having the preknowledge of the object geometry. This paper introduces a novel adaptive algorithm for absolute 3D shape measurement with the assistance of the object computer-aided-design (CAD) model. The proposed algorithm includes the following major steps: (1) export the 3D point cloud data from the CAD model; (2) transform the CAD model into the camera perspective; (3) obtain a wrapped phase map from three phase-shifted fringe images; and (4) retrieve absolute phase and 3D geometry assisted by the CAD model. We demonstrate that if object CAD models are available, such an algorithm is efficient in recovering absolute 3D geometries of both simple and complex objects with only three phase-shifted fringe images.

  4. A unified spray forming model for the prediction of billet shape geometry

    DEFF Research Database (Denmark)

    Hattel, Jesper; Pryds, Nini

    2004-01-01

    In the present work a unified model for simulating the spray forming process has been developed. Models for the atomization and the deposition processes have been coupled together in order to obtain a new unified description of the spray forming process. The model is able to predict the shape...... and the temperatures of a spray-formed billet and takes into account the thermal coupling between the gas and the droplets, the change in droplet size distribution along the r-axis in the spray cone and the shading effect. The deposition describes the evolution of the preform with time. For this stage a novel 3D model......, which allows the atomizer to be placed asymmetrically over the substrate and also includes the withdrawal of the deposit, was developed. This makes it possible to model not only the growth of a Gaussian shaped preform in which case the spray axis and the rotation axis coincide, but also the surface...

  5. A Dynamic Mesh-Based Approach to Model Melting and Shape of an ESR Electrode

    Science.gov (United States)

    Karimi-Sibaki, E.; Kharicha, A.; Bohacek, J.; Wu, M.; Ludwig, A.

    2015-10-01

    This paper presents a numerical method to investigate the shape of tip and melt rate of an electrode during electroslag remelting process. The interactions between flow, temperature, and electromagnetic fields are taken into account. A dynamic mesh-based approach is employed to model the dynamic formation of the shape of electrode tip. The effect of slag properties such as thermal and electrical conductivities on the melt rate and electrode immersion depth is discussed. The thermal conductivity of slag has a dominant influence on the heat transfer in the system, hence on melt rate of electrode. The melt rate decreases with increasing thermal conductivity of slag. The electrical conductivity of slag governs the electric current path that in turn influences flow and temperature fields. The melting of electrode is a quite unstable process due to the complex interaction between the melt rate, immersion depth, and shape of electrode tip. Therefore, a numerical adaptation of electrode position in the slag has been implemented in order to achieve steady state melting. In fact, the melt rate, immersion depth, and shape of electrode tip are interdependent parameters of process. The generated power in the system is found to be dependent on both immersion depth and shape of electrode tip. In other words, the same amount of power was generated for the systems where the shapes of tip and immersion depth were different. Furthermore, it was observed that the shape of electrode tip is very similar for the systems running with the same ratio of power generation to melt rate. Comparison between simulations and experimental results was made to verify the numerical model.

  6. "Shape function + memory mechanism"-based hysteresis modeling of magnetorheological fluid actuators

    Science.gov (United States)

    Qian, Li-Jun; Chen, Peng; Cai, Fei-Long; Bai, Xian-Xu

    2018-03-01

    A hysteresis model based on "shape function + memory mechanism" is presented and its feasibility is verified through modeling the hysteresis behavior of a magnetorheological (MR) damper. A hysteresis phenomenon in resistor-capacitor (RC) circuit is first presented and analyzed. In the hysteresis model, the "memory mechanism" originating from the charging and discharging processes of the RC circuit is constructed by adopting a virtual displacement variable and updating laws for the reference points. The "shape function" is achieved and generalized from analytical solutions of the simple semi-linear Duhem model. Using the approach, the memory mechanism reveals the essence of specific Duhem model and the general shape function provides a direct and clear means to fit the hysteresis loop. In the frame of the structure of a "Restructured phenomenological model", the original hysteresis operator, i.e., the Bouc-Wen operator, is replaced with the new hysteresis operator. The comparative work with the Bouc-Wen operator based model demonstrates superior performances of high computational efficiency and comparable accuracy of the new hysteresis operator-based model.

  7. A stress-induced phase transition model for semi-crystallize shape memory polymer

    Science.gov (United States)

    Guo, Xiaogang; Zhou, Bo; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2014-03-01

    The developments of constitutive models for shape memory polymer (SMP) have been motivated by its increasing applications. During cooling or heating process, the phase transition which is a continuous time-dependent process happens in semi-crystallize SMP and the various individual phases form at different temperature and in different configuration. Then, the transformation between these phases occurred and shape memory effect will emerge. In addition, stress applied on SMP is an important factor for crystal melting during phase transition. In this theory, an ideal phase transition model considering stress or pre-strain is the key to describe the behaviors of shape memory effect. So a normal distributed model was established in this research to characterize the volume fraction of each phase in SMP during phase transition. Generally, the experiment results are partly backward (in heating process) or forward (in cooling process) compared with the ideal situation considering delay effect during phase transition. So, a correction on the normal distributed model is needed. Furthermore, a nonlinear relationship between stress and phase transition temperature Tg is also taken into account for establishing an accurately normal distributed phase transition model. Finally, the constitutive model which taking the stress as an influence factor on phase transition was also established. Compared with the other expressions, this new-type model possesses less parameter and is more accurate. For the sake of verifying the rationality and accuracy of new phase transition and constitutive model, the comparisons between the simulated and experimental results were carried out.

  8. A unified spray forming model for the prediction of billet shape geometry

    International Nuclear Information System (INIS)

    Hattel, J.H.; Pryds, N.H.

    2004-01-01

    In the present work a unified model for simulating the spray forming process has been developed. Models for the atomization and the deposition processes have been coupled together in order to obtain a new unified description of the spray forming process. The model is able to predict the shape and the temperatures of a spray-formed billet and takes into account the thermal coupling between the gas and the droplets, the change in droplet size distribution along the r-axis in the spray cone and the shading effect. The deposition describes the evolution of the preform with time. For this stage a novel 3D model, which allows the atomizer to be placed asymmetrically over the substrate and also includes the withdrawal of the deposit, was developed. This makes it possible to model not only the growth of a Gaussian shaped preform in which case the spray axis and the rotation axis coincide, but also the surface evolution during billet growth. For this purpose, shading must be taken into account as a core part of the surface evolution algorithm. The unified model involves coupling of three sub models for the atomization, the deposition and the shape of the billet. This coupling, which is a central part of the present work, is also described. Results from the integrated model are presented and the potential for better process understanding as well as process optimization is evident

  9. Constitutive modeling of SMA SMP multifunctional high performance smart adaptive shape memory composite

    International Nuclear Information System (INIS)

    Jarali, Chetan S; Raja, S; Upadhya, A R

    2010-01-01

    Materials design involving the thermomechanical constitutive modeling of shape memory alloy (SMA) and shape memory polymer (SMP) composites is a key topic in the development of smart adaptive shape memory composites (SASMC). In this work, a constitutive model for SASMC is developed. First, a one-dimensional SMA model, which can simulate the pseudoelastic (PE) and shape memory effects (SME) is presented. Subsequently, a one-dimensional SMP model able to reproduce the SME is addressed. Both SMA and SMP models are based on a single internal state variable, namely the martensite fraction and the frozen fraction, which can be expressed as a function of temperature. A consistent form of the analytical solution for the SMP model is obtained using the fourth-order Runge–Kutta method. Finally, the SASMC constitutive model is proposed, following two analytical homogenization approaches. One approach is based on an equivalent inclusion method and the other approach is the rule of mixtures. The SMA and SMP constitutive models are validated independently with experimental results. However, the validation of the composite model is performed using the two homogenization approaches and a close agreement in results is observed. Results regarding the isothermal and thermomechanical stress–strain responses are analyzed as a function of SMA volume fraction. Further, it is concluded that the proposed composite model is able to reproduce consistently the overall composite response by taking into consideration not only the phase transformations, variable modulus and transformation stresses in SMA but also the variable modulus, the evolution of stored strain and thermal strain in the SMP

  10. Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity

    Science.gov (United States)

    Wobus, C.W.; Kean, J.W.; Tucker, G.E.; Anderson, R. Scott

    2008-01-01

    The cross-sectional shape of a natural river channel controls the capacity of the system to carry water off a landscape, to convey sediment derived from hillslopes, and to erode its bed and banks. Numerical models that describe the response of a landscape to changes in climate or tectonics therefore require formulations that can accommodate evolution of channel cross-sectional geometry. However, fully two-dimensional (2-D) flow models are too computationally expensive to implement in large-scale landscape evolution models, while available simple empirical relationships between width and discharge do not adequately capture the dynamics of channel adjustment. We have developed a simplified 2-D numerical model of channel evolution in a cohesive, detachment-limited substrate subject to steady, unidirectional flow. Erosion is assumed to be proportional to boundary shear stress, which is calculated using an approximation of the flow field in which log-velocity profiles are assumed to apply along vectors that are perpendicular to the local channel bed. Model predictions of the velocity structure, peak boundary shear stress, and equilibrium channel shape compare well with predictions of a more sophisticated but more computationally demanding ray-isovel model. For example, the mean velocities computed by the two models are consistent to within ???3%, and the predicted peak shear stress is consistent to within ???7%. Furthermore, the shear stress distributions predicted by our model compare favorably with available laboratory measurements for prescribed channel shapes. A modification to our simplified code in which the flow includes a high-velocity core allows the model to be extended to estimate shear stress distributions in channels with large width-to-depth ratios. Our model is efficient enough to incorporate into large-scale landscape evolution codes and can be used to examine how channels adjust both cross-sectional shape and slope in response to tectonic and climatic

  11. Probability density function shape sensitivity in the statistical modeling of turbulent particle dispersion

    Science.gov (United States)

    Litchford, Ron J.; Jeng, San-Mou

    1992-01-01

    The performance of a recently introduced statistical transport model for turbulent particle dispersion is studied here for rigid particles injected into a round turbulent jet. Both uniform and isosceles triangle pdfs are used. The statistical sensitivity to parcel pdf shape is demonstrated.

  12. Extraction of the mode shapes of a segmented ship model with a hydroelastic response

    Directory of Open Access Journals (Sweden)

    Yooil Kim

    2015-11-01

    Full Text Available The mode shapes of a segmented hull model towed in a model basin were predicted using both the Proper Orthogonal Decomposition (POD and cross random decrement technique. The proper orthogonal decomposition, which is also known as Karhunen-Loeve decomposition, is an emerging technology as a useful signal processing technique in structural dynamics. The technique is based on the fact that the eigenvectors of a spatial coherence matrix become the mode shapes of the system under free and randomly excited forced vibration conditions. Taking advantage of the sim-plicity of POD, efforts have been made to reveal the mode shapes of vibrating flexible hull under random wave ex-citation. First, the segmented hull model of a 400 K ore carrier with 3 flexible connections was towed in a model basin under different sea states and the time histories of the vertical bending moment at three different locations were meas-ured. The measured response time histories were processed using the proper orthogonal decomposition, eventually to obtain both the first and second vertical vibration modes of the flexible hull. A comparison of the obtained mode shapes with those obtained using the cross random decrement technique showed excellent correspondence between the two results.

  13. Building and Testing a Statistical Shape Model of the Human Ear Canal

    DEFF Research Database (Denmark)

    Paulsen, Rasmus Reinhold; Larsen, Rasmus; Laugesen, Søren

    2002-01-01

    Today the design of custom in-the-ear hearing aids is based on personal experience and skills and not on a systematic description of the variation of the shape of the ear canal. In this paper it is described how a dense surface point distribution model of the human ear canal is built based on a t...

  14. Lightcurves for Shape Modeling: 852 Wladilena, 1089 Tama, and 1180 Rita

    Science.gov (United States)

    Polishook, David

    2012-10-01

    The folded lightcurves and synodic periods of 852 Wladilena, 1089 Tama, and 1180 Rita are reported. The data are used by Hanus et al. (2012) to derive the rotation axis and to construct a shape model by applying the inversion lightcurve technique.

  15. A 3D active shape model driven by fuzzy inference : application to cardiac CT and MR

    NARCIS (Netherlands)

    Assen, van H.C.; Danilouchkine, M.G.; Dirksen, M.S.; Reiber, J.H.C.; Lelieveldt, B.P.F.

    2008-01-01

    Abstract—Manual quantitative analysis of cardiac left ventricular function using Multislice CT and MR is arduous because of the large data volume. In this paper, we present a 3-D active shape model (ASM) for semiautomatic segmentation of cardiac CT and MRvolumes, without the requirement of

  16. Pedestrian detection and tracking using a mixture of view-based shape-texture models

    NARCIS (Netherlands)

    Munder, S.; Schnörr, C.; Gavrila, D.M.

    2008-01-01

    This paper presents a robust multicue approach to the integrated detection and tracking of pedestrians in a cluttered urban environment. A novel spatiotemporal object representation is proposed, which combines a generative shape model and a discriminative texture classifier, both of which are

  17. Numerical Modeling of Induction Heating Process using Inductors with Circular Shape Turns

    Directory of Open Access Journals (Sweden)

    Mihaela Novac

    2008-05-01

    Full Text Available This paper is focused on the problemof numerical modeling of electromagneticfield coupled with the thermal one in theheating process of the steel billets, usinginductors with circular shape turns. As resultswe have: electromagnetic field lines evolutionand map temperatures in piece at the endingof heating process.

  18. Shape Optimization for Navier-Stokes Equations with Algebraic Turbulence Model: Existence Analysis

    Czech Academy of Sciences Publication Activity Database

    Bulíček, M.; Haslinger, J.; Málek, J.; Stebel, Jan

    2009-01-01

    Roč. 60, č. 2 (2009), s. 185-212 ISSN 0095-4616 R&D Projects: GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : optimal shape design * paper machine headbox * incompressible non-Newtonian fluid * algebraic turbulence model * outflow boundary condition Subject RIV: BA - General Mathematics Impact factor: 0.757, year: 2009

  19. Study on critical heat flux in narrow rectangular channel with repeated-rib roughness. 1. Experimental facility and preliminary experiments

    International Nuclear Information System (INIS)

    Kinoshita, Hidetaka; Terada, Atsuhiko; Kaminaga, Masanori; Hino, Ryutaro

    2001-10-01

    In the design of a spallation target system, the water cooling system, for example a proton beam window and a safety hull, is used with narrow channels, in order to remove high heat flux and prevent lowering of system performance by absorption of neutron. And in narrow channel, heat transfer enhancement using 2-D rib is considered for reduction the cost of cooling component and decrease inventory of water in the cooling system, that is, decrease of the amount of irradiated water. But few studies on CHF with rib have been carried out. Experimental and analytical studies with rib-roughened test section, in 10:1 ratio of pitch to height, are being carried out in order to clarify the CHF in rib-roughened channel. This paper presents the review of previous researches on heat transfer in channel with rib roughness, overview of the test facility and the preliminary experimental and analytical results. As a result, wall friction factors were about 3 times as large as that of smooth channel, and heat transfer coefficients are about 2 times as large as that of smooth channel. The obtained CHF was as same as previous mechanistic model by Sudo. (author)

  20. Tuning and Test of Fragmentation Models Based on Identified Particles and Precision Event Shape Data

    CERN Document Server

    Abreu, P; Adye, T; Ajinenko, I; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Libby, J; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; Naughton, J M; Maehlum, G; Mahon, J R; Maio, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Pain, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sahr, O; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Siegrist, P; Silvestre, R; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sokolov, A; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zucchelli, G C; Zumerle, G

    1996-01-01

    Event shape and charged particle inclusive distributions are measured using 750000 decays of the $Z$ to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by fitting the models to these DELPHI data as well as to identified particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identified particles.

  1. SHERMAN - A shape-based thermophysical model II. Application to 8567 (1996 HW1)

    Science.gov (United States)

    Howell, E. S.; Magri, C.; Vervack, R. J.; Nolan, M. C.; Taylor, P. A.; Fernández, Y. R.; Hicks, M. D.; Somers, J. M.; Lawrence, K. J.; Rivkin, A. S.; Marshall, S. E.; Crowell, J. L.

    2018-03-01

    We apply a new shape-based thermophysical model, SHERMAN, to the near-Earth asteroid (NEA) 8567 (1996 HW1) to derive surface properties. We use the detailed shape model of Magri et al. (2011) for this contact binary NEA to analyze spectral observations (2-4.1 microns) obtained at the NASA IRTF on several different dates to find thermal parameters that match all the data. Visible and near-infrared (0.8-2.5 microns) spectral observations are also utilized in a self-consistent way. We find that an average visible albedo of 0.33, thermal inertia of 70 (SI units) and surface roughness of 50% closely match the observations. The shape and orientation of the asteroid is very important to constrain the thermal parameters to be consistent with all the observations. Multiple viewing geometries are equally important to achieve a robust solution for small, non-spherical NEAs. We separate the infrared beaming effects of shape, viewing geometry and surface roughness for this asteroid and show how their effects combine. We compare the diameter and albedo that would be derived from the thermal observations assuming a spherical shape with those from the shape-based model. We also discuss how observations from limited viewing geometries compare to the solution from multiple observations. The size that would be derived from the individual observation dates varies by 20% from the best-fit solution, and can be either larger or smaller. If the surface properties are not homogeneous, many solutions are possible, but the average properties derived here are very tightly constrained by the multiple observations, and give important insights into the nature of small NEAs.

  2. A computer graphics based model for scattering from objects of arbitrary shapes in the optical region

    Science.gov (United States)

    Goel, Narendra S.; Rozehnal, Ivan; Thompson, Richard L.

    1991-01-01

    A computer-graphics-based model, named DIANA, is presented for generation of objects of arbitrary shape and for calculating bidirectional reflectances and scattering from them, in the visible and infrared region. The computer generation is based on a modified Lindenmayer system approach which makes it possible to generate objects of arbitrary shapes and to simulate their growth, dynamics, and movement. Rendering techniques are used to display an object on a computer screen with appropriate shading and shadowing and to calculate the scattering and reflectance from the object. The technique is illustrated with scattering from canopies of simulated corn plants.

  3. Uncertainty analysis of a one-dimensional constitutive model for shape memory alloy thermomechanical description

    DEFF Research Database (Denmark)

    Oliveira, Sergio A.; Savi, Marcelo A.; Santos, Ilmar F.

    2014-01-01

    The use of shape memory alloys (SMAs) in engineering applications has increased the interest of the accuracy analysis of their thermomechanical description. This work presents an uncertainty analysis related to experimental tensile tests conducted with shape memory alloy wires. Experimental data...... are compared with numerical simulations obtained from a constitutive model with internal constraints employed to describe the thermomechanical behavior of SMAs. The idea is to evaluate if the numerical simulations are within the uncertainty range of the experimental data. Parametric analysis is also developed...

  4. Approximate Mathematical Modeling of Osmotic Dehydration of Cone-Shaped Fruits and Vegetables in Hypertonic Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Sirousazar

    2017-07-01

    Full Text Available Water loss kinetics in osmotic dehydration of cone-shaped fruits and vegetables was modeled on the basis of diffusion mechanism, using the Fick’s second law. The model was developed by taking into account the influences of the fruit geometrical characteristics, initial water content of fruit, water diffusion coefficient in fruit, and the water concentration in hypertonic solution. Based on the obtained model, it was shown that the water diffusion coefficient and the initial water concentration of fruit have direct effects on the dehydration rate and also inverse influence on the dehydration duration. The geometrical parameters of fruit and water concentration in hypertonic solution showed direct effect on the dehydration duration as well as inverse effect on the dehydration rate. The presented model seems to be useful tool to predict the dehydration kinetics of cone-shaped fruit during osmotic dehydration process and to optimize the process prior to perform the experiments.

  5. Modelling stochastic chances in curve shape, with an application to cancer diagnostics

    DEFF Research Database (Denmark)

    Hobolth, A; Jensen, Eva B. Vedel

    2000-01-01

    Often, the statistical analysis of the shape of a random planar curve is based on a model for a polygonal approximation to the curve. In the present paper, we instead describe the curve as a continuous stochastic deformation of a template curve. The advantage of this continuous approach is that t......Often, the statistical analysis of the shape of a random planar curve is based on a model for a polygonal approximation to the curve. In the present paper, we instead describe the curve as a continuous stochastic deformation of a template curve. The advantage of this continuous approach...... is that the parameters in the model do not relate to a particular polygonal approximation. A somewhat similar approach has been used by Kent et al. (1996), who describe the limiting behaviour of a model with a first-order Markov property as the landmarks on the curve become closely spaced; see also Grenander(1993...

  6. Lip-Synching Using Speaker-Specific Articulation, Shape and Appearance Models

    Directory of Open Access Journals (Sweden)

    Gaspard Breton

    2009-01-01

    Full Text Available We describe here the control, shape and appearance models that are built using an original photogrammetric method to capture characteristics of speaker-specific facial articulation, anatomy, and texture. Two original contributions are put forward here: the trainable trajectory formation model that predicts articulatory trajectories of a talking face from phonetic input and the texture model that computes a texture for each 3D facial shape according to articulation. Using motion capture data from different speakers and module-specific evaluation procedures, we show here that this cloning system restores detailed idiosyncrasies and the global coherence of visible articulation. Results of a subjective evaluation of the global system with competing trajectory formation models are further presented and commented.

  7. A novel methodology to model the cooling processes of packed horticultural produce using 3D shape models

    Science.gov (United States)

    Gruyters, Willem; Verboven, Pieter; Rogge, Seppe; Vanmaercke, Simon; Ramon, Herman; Nicolai, Bart

    2017-10-01

    Freshly harvested horticultural produce require a proper temperature management to maintain their high economic value. Towards this end, low temperature storage is of crucial importance to maintain a high product quality. Optimizing both the package design of packed produce and the different steps in the postharvest cold chain can be achieved by numerical modelling of the relevant transport phenomena. This work presents a novel methodology to accurately model both the random filling of produce in a package and the subsequent cooling process. First, a cultivar-specific database of more than 100 realistic CAD models of apple and pear fruit is built with a validated geometrical 3D shape model generator. To have an accurate representation of a realistic picking season, the model generator also takes into account the biological variability of the produce shape. Next, a discrete element model (DEM) randomly chooses surface meshed bodies from the database to simulate the gravitational filling process of produce in a box or bin, using actual mechanical properties of the fruit. A computational fluid dynamics (CFD) model is then developed with the final stacking arrangement of the produce to study the cooling efficiency of packages under several conditions and configurations. Here, a typical precooling operation is simulated to demonstrate the large differences between using actual 3D shapes of the fruit and an equivalent spheres approach that simplifies the problem drastically. From this study, it is concluded that using a simplified representation of the actual fruit shape may lead to a severe overestimation of the cooling behaviour.

  8. A Nonparametric Shape Prior Constrained Active Contour Model for Segmentation of Coronaries in CTA Images

    Directory of Open Access Journals (Sweden)

    Yin Wang

    2014-01-01

    Full Text Available We present a nonparametric shape constrained algorithm for segmentation of coronary arteries in computed tomography images within the framework of active contours. An adaptive scale selection scheme, based on the global histogram information of the image data, is employed to determine the appropriate window size for each point on the active contour, which improves the performance of the active contour model in the low contrast local image regions. The possible leakage, which cannot be identified by using intensity features alone, is reduced through the application of the proposed shape constraint, where the shape of circular sampled intensity profile is used to evaluate the likelihood of current segmentation being considered vascular structures. Experiments on both synthetic and clinical datasets have demonstrated the efficiency and robustness of the proposed method. The results on clinical datasets have shown that the proposed approach is capable of extracting more detailed coronary vessels with subvoxel accuracy.

  9. Rib fracture in Prognathodon saturator (Mosasauridae, Late Cretaceous)

    NARCIS (Netherlands)

    Schulp, Anne S.; Walenkamp, G. H I M; Hofman, P.A.M.; Rothschild, B. M.; Jagt, J. W M

    2004-01-01

    Two unusual bumps occur on the internal surface of a rib of the marine reptile Prognathodon saturator from the Upper Cretaceous (Maastrichtian) of Maastricht, The Netherlands. These bumps are interpreted as stress fractures, possibly related to agonistic behaviour.

  10. Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

    Science.gov (United States)

    Galos, David; Taylor, Benjamin; McLaurin, Toni

    2017-01-01

    Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

  11. Transmission loss of orthogonally rib-stiffened double-panel structures with cavity absorption.

    Science.gov (United States)

    Xin, F X; Lu, T J

    2011-04-01

    The transmission loss of sound through infinite orthogonally rib-stiffened double-panel structures having cavity-filling fibrous sound absorptive materials is theoretically investigated. The propagation of sound across the fibrous material is characterized using an equivalent fluid model, and the motions of the rib-stiffeners are described by including all possible vibrations, i.e., flexural displacements, bending, and torsional rotations. The effects of fluid-structure coupling are account for by enforcing velocity continuity conditions at fluid-panel interfaces. By taking full advantage of the periodic nature of the double-panel, the space-harmonic approach and virtual work principle are applied to solve the sets of resultant governing equations, which are eventually truncated as a finite system of simultaneous algebraic equations and numerically solved insofar as the solution converges. To validate the proposed model, a comparison between the present model predictions and existing numerical and experimental results for a simplified version of the double-panel structure is carried out, with overall agreement achieved. The model is subsequently employed to explore the influence of the fluid-structure coupling between fluid in the cavity and the two panels on sound transmission across the orthogonally rib-stiffened double-panel structure. Obtained results demonstrate that this fluid-structure coupling affects significantly sound transmission loss (STL) at low frequencies and cannot be ignored when the rib-stiffeners are sparsely distributed. As a highlight of this research, an integrated optimal algorithm toward lightweight, high-stiffness and superior sound insulation capability is proposed, based on which a preliminary optimal design of the double-panel structure is performed.

  12. Delayed pneumothorax complicating minor rib fracture after chest trauma.

    Science.gov (United States)

    Lu, Ming-Shian; Huang, Yao-Kuang; Liu, Yun-Hen; Liu, Hui-Ping; Kao, Chiung-Lun

    2008-06-01

    Pneumothorax (PTX) after trauma is a preventable cause of death. Drainage procedures such as chest tube insertion have been traditionally advocated to prevent fatal tension PTX. We evaluated the safety of close observation in patients with delayed PTX complicating rib fracture after minor chest trauma. Adult patients (>18 years) with a diagnosis of chest trauma and 3 or fewer fractured ribs were reviewed. Case patients were divided according to age, location and number of fractured ribs, mechanism of trauma, and initial pulmonary complication after thoracic trauma for comparative analysis. There were 207 male (70.2%) and 88 female (29.8%) patients whose ages ranged from 18 to 93 years (median, 55 years). The mechanisms of trauma were a motor vehicle accident in 207 patients, falls in 66, pedestrian injury in 10, and assaults in 14. Ninety-five patients sustained 1 rib fracture, 95 had 2 rib fractures, and 105 suffered 3 rib fractures. Right-sided injury occurred in 164 cases, left-sided injury did in 127, and bilateral injury did in 4. The most frequent location of rib fractures was from the fourth rib to the ninth rib. The initial pulmonary complications after trauma were PTX in 16 patients, hemothorax in 43, pneumohemothorax in 14, lung contusion in 75, and isolated subcutaneous emphysema (SubcEmph) in 33. Thirty percent of the patients (n = 5/16) who presented with traumatic PTX were observed safely without drainage. Delayed PTX was recorded in 16 patients, occurring mostly during the first 2 days of their admission. Associated extrathoracic injury was recorded in 189 patients. The mean hospital stay of the patients was 7.66 days. Longer hospital stay was related to increasing number of fractured ribs, need for thoracic drainage, and the presence of associated extrathoracic injury. The mortality rate for the entire group was 2%. The presence of SubcEmph was the only risk factor associated with the development of delayed PTX. Patients sustaining blunt chest

  13. Numerical investigation of heat transfer enhancement in ribbed channel for the first wall of DFLL-TBM in ITER

    International Nuclear Information System (INIS)

    Jin Qiang; Liu Songlin; Li Min; Wang Weihua

    2012-01-01

    As an important component of Dual Functional Lithium Lead-Test Blanket Module (DFLL-TBM), the first wall (FW) must withstand and remove the heat flux from the plasma (q″ = 0.3 MW/m 2 ) and high nuclear power deposited in the structure at normal plasma operation scenario of ITER. In this paper the transverse ribs arranged along the plasma facing inner wall surface were used to enhance the heat transfer capability. After the validation compared with empirical correlations the Standard k–ω model was employed to do the numerical simulation using FLUENT code to investigate the heat transfer efficiency and flow performance of coolant in the ribbed channel preliminarily. The perforation on the bottom of rib was proposed near the lower heat transfer area (LHTA) to improve the heat transfer performance according to results of analyses.

  14. Dome Structures Above Sills and Saucer-Shaped Sills: Insights From Experimental Modeling

    Science.gov (United States)

    Planke, S.; Galland, O.; Malthe-Sørenssen, A.

    2007-12-01

    Saucer-shaped magma and sand intrusions are common features in sedimentary basins. They result from fundamental processes for the emplacement of fluids in shallow sedimentary basins. Seismic data show that the overburden above saucer-shaped intrusions is usually deformed and exhibits a dome-like structure. The formation of such structures, and the associated deformation, are of primary importance in the evolution of petroleum systems. In this presentation, we report on experimental investigation of the deformation processes associated with the intrusion of saucer-shaped intrusions into sedimentary basins. The experimental setup consists of molten low-viscosity oil injected into fine-grained silica flour (see Galland et al., this session). It properly simulates the emplacement of saucer-shaped intrusions and the deformation of the country rock. During experiments, the surface of the model is digitalized through a structured light technique based on moiré projection principle. Such a tool provides topographic maps of the model and allows a periodic (every 1.5 s) monitoring of the model surface. When the model magma starts intruding, a symetrical dome rises above the inlet. As injection proceeds, the dome inflates and widens. Subsequently, the dome evolves to a plateau-like feature, with nearly flat surface and steep edges. The plateau keeps lifting up, but nearly stoppes widening. At the end of the experiments, the intruding liquid erupts at the edge of the plateau. The intrusion formed in the experiment is a typical saucer-shaped sill. The evolution of the deforming surface reflects the evolution of the intrusion. We infer that the first doming phase corresponds to the emplacement of a horizontal basal sill by open fracturing. The dome-to-plateau transition corresponds to a transition of the liquid emplacement mechanism from basal sill to inclined sheet. We suggest that the emplacement of the inclined sheets results from shear fracturing at the dome edge.

  15. Weighted regularized statistical shape space projection for breast 3D model reconstruction.

    Science.gov (United States)

    Ruiz, Guillermo; Ramon, Eduard; García, Jaime; Sukno, Federico M; Ballester, Miguel A González

    2018-05-02

    The use of 3D imaging has increased as a practical and useful tool for plastic and aesthetic surgery planning. Specifically, the possibility of representing the patient breast anatomy in a 3D shape and simulate aesthetic or plastic procedures is a great tool for communication between surgeon and patient during surgery planning. For the purpose of obtaining the specific 3D model of the breast of a patient, model-based reconstruction methods can be used. In particular, 3D morphable models (3DMM) are a robust and widely used method to perform 3D reconstruction. However, if additional prior information (i.e., known landmarks) is combined with the 3DMM statistical model, shape constraints can be imposed to improve the 3DMM fitting accuracy. In this paper, we present a framework to fit a 3DMM of the breast to two possible inputs: 2D photos and 3D point clouds (scans). Our method consists in a Weighted Regularized (WR) projection into the shape space. The contribution of each point in the 3DMM shape is weighted allowing to assign more relevance to those points that we want to impose as constraints. Our method is applied at multiple stages of the 3D reconstruction process. Firstly, it can be used to obtain a 3DMM initialization from a sparse set of 3D points. Additionally, we embed our method in the 3DMM fitting process in which more reliable or already known 3D points or regions of points, can be weighted in order to preserve their shape information. The proposed method has been tested in two different input settings: scans and 2D pictures assessing both reconstruction frameworks with very positive results. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Upper extremity and rib stress fractures in a child

    International Nuclear Information System (INIS)

    Moon, B.S.; Price, C.T.; Campbell, J.B.

    1998-01-01

    Stress fractures in children are rare compared with the incidence in [ults. This report describes an 11-year-old girl with stress fractures of the acromion, clavicle, and first rib on the left and contralateral fractures of the first and second ribs. It was eventually discovered that these fractures were caused by a nervous tic consisting of repetitive, vigorous shrugging and translation of the shoulders. (orig.)

  17. Lower thoracic rib stress fractures in baseball pitchers.

    Science.gov (United States)

    Gerrie, Brayden J; Harris, Joshua D; Lintner, David M; McCulloch, Patrick C

    2016-01-01

    Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4-6 weeks with a graduated return to throwing and competition by 8-10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.

  18. Rib fractures in coronary bypass patients: radionuclide detection

    International Nuclear Information System (INIS)

    Greenwald, L.V.; Baisden, C.E.; Symbas, P.N.

    1983-01-01

    Sternal retraction can cause the first rib to be fractured posteriorly, injuring the brachial plexus. The authors conducted bone scans of 24 consecutive open-heart surgery patients and found an unexpectedly high number of rib fractures which in all but one case had not been seen on the chest radiograph. Bone scans are recommended whenever there is unexplained non-incisional pain in a patient who has undergone sternal retraction

  19. The Place of Ultrasonography in the Evaluation of Rib Fractures

    OpenAIRE

    Fulya Bakılan; Gökhan Yüce; Ahmet Çağdaş Biçen; Tanju Keten

    2015-01-01

    Objective: The aim of this study was to investigate whether ultrasonography is superior to chest x-ray in detecting rib fractures in patients with minor blunt chest trauma and chest pain. Materials and Methods: Ultrasonography findings of 32 patients with minor blunt chest trauma showing no evidence of a rib fracture on anteroposterior chest x-rays, were documented. Presence of cortical discontinuities, acoustic shadows, reverberation artifacts, and hematoma by ultrasonography was...

  20. Outcomes after operative management of symptomatic rib nonunion.

    Science.gov (United States)

    Gauger, Erich M; Hill, Brian W; Lafferty, Paul M; Cole, Peter A

    2015-06-01

    To report the outcomes of rib reconstruction after painful nonunion. Retrospective case series. Level I trauma center. Between November 2007 and May 2013, 10 patients who presented with 16 rib nonunions and disabling pain were treated with reconstruction of their nonunited rib fractures. Rib nonunion reconstruction predominately with iliac crest bone graft and a tension band plate with a locked precontoured plating system for ribs. Demographic data, mechanism of injury, and number of rib nonunions were recorded. Operative procedure, length of follow-up, complications, Short Form Survey 36, and a patient questionnaire were also captured and documented. Eight of the 10 patients sustained their original fractures from a fall. Outcomes were available for the 10 patients at a mean follow-up of up of 18.6 months (range, 3-46 months). All 16 ribs went on to union with a mean time from reconstruction to union of 14.7 weeks (range, 12-24 weeks). At final follow-up, the mean mental and physical component Short Form Survey 36 scores were 54.4 and 43.5, respectively. Eight of the 10 patients were able to return to work and/or previous activities without limitations. Complications included 1 wound infection that resolved after irrigation and debridement with adjunctive antibiotics. One symptomatic implant was removed. Ten patients with 16 symptomatic rib nonunions were reconstructed using autologous bone graft and implant/mesh fixation manifesting in successful union with improved patient function and a low rate of complications. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

  1. Ultrasonography as a better diagnostic efficiency in rib fracture

    OpenAIRE

    UZUN, Metin; BEKSAÇ, Burak; KARATAŞ, Adnan; KÜÇÜKDURMAZ, Fatih; KIRCALI, Bahar ANAYURDU; TETİK, Cihangir

    2013-01-01

    In this study, our aim was to demonstrate the need of use of ultrasonography in rib fractures in order not to face medicolegal problems. One hundred patients admitted to our emergency service with mild to moderate blunt thorax trauma were included in our study prospectively. The inclusion criteria were pain upon palpation of ribs, deep inspiration, coughing but no any other pathologies like a pneumothorax, hemothorax. All patients are evaluated with ultrasonography (USG) and direct X-rays. X-...

  2. An analysis of 214 cases of rib fractures

    Directory of Open Access Journals (Sweden)

    Sule Karadayi

    2011-01-01

    Full Text Available INTRODUCTION: Rib fractures are the most common type of injury associated with trauma to the thorax. In this study, we investigated whether morbidity and mortality rates increased in correlation with the number of fractured ribs. MATERIALS AND METHODS: Data from 214 patients with rib fractures who applied or were referred to our clinic between January 2007 and December 2008 were retrospectively evaluated. The patients were allocated into three groups according to the number of fractures: 1 patients with an isolated rib fracture (RF1 (n = 50, 23.4%, 2 patients with two rib fractures (RF2 (n = 53, 24.8%, and 3 patients with more than two rib fractures (RF3 (n = 111, 51.9%. The patients were evaluated and compared according to the number of rib fractures, mean age, associated chest injuries (hemothorax, pneumothorax, and/or pulmonary contusion, and co-existing injuries to other systems. FINDINGS: The mean age of the patients was 51.5 years. The distribution of associated chest injuries was 30% in group RF1, 24.6% in group RF2, and 75.6% in group RF3 (p<0.05. Co-existing injuries to other systems were 24% in group RF1, 23.2% in group RF2, and 52.6% in group RF3 (p<0.05. Two patients (4% in group RF1, 2 patients (3.8% in group RF2, and 5 patients (4.5% in group RF3 (total n = 9; 4.2% died. CONCLUSION: Patients with any number of rib fractures should be carefully screened for co-existing injuries in other body systems and hospitalized to receive proper treatment.

  3. The compressed breast during mammography and breast tomosynthesis: in vivo shape characterization and modeling

    Science.gov (United States)

    Rodríguez-Ruiz, Alejandro; Agasthya, Greeshma A.; Sechopoulos, Ioannis

    2017-09-01

    To characterize and develop a patient-based 3D model of the compressed breast undergoing mammography and breast tomosynthesis. During this IRB-approved, HIPAA-compliant study, 50 women were recruited to undergo 3D breast surface imaging with structured light (SL) during breast compression, along with simultaneous acquisition of a tomosynthesis image. A pair of SL systems were used to acquire 3D surface images by projecting 24 different patterns onto the compressed breast and capturing their reflection off the breast surface in approximately 12-16 s. The 3D surface was characterized and modeled via principal component analysis. The resulting surface model was combined with a previously developed 2D model of projected compressed breast shapes to generate a full 3D model. Data from ten patients were discarded due to technical problems during image acquisition. The maximum breast thickness (found at the chest-wall) had an average value of 56 mm, and decreased 13% towards the nipple (breast tilt angle of 5.2°). The portion of the breast not in contact with the compression paddle or the support table extended on average 17 mm, 18% of the chest-wall to nipple distance. The outermost point along the breast surface lies below the midline of the total thickness. A complete 3D model of compressed breast shapes was created and implemented as a software application available for download, capable of generating new random realistic 3D shapes of breasts undergoing compression. Accurate characterization and modeling of the breast curvature and shape was achieved and will be used for various image processing and clinical tasks.

  4. Improvements of an objective model of compressed breasts undergoing mammography: Generation and characterization of breast shapes.

    Science.gov (United States)

    Rodríguez-Ruiz, Alejandro; Feng, Steve Si Jia; van Zelst, Jan; Vreemann, Suzan; Mann, Jessica Rice; D'Orsi, Carl Joseph; Sechopoulos, Ioannis

    2017-06-01

    To develop a set of accurate 2D models of compressed breasts undergoing mammography or breast tomosynthesis, based on objective analysis, to accurately characterize mammograms with few linearly independent parameters, and to generate novel clinically realistic paired cranio-caudal (CC) and medio-lateral oblique (MLO) views of the breast. We seek to improve on an existing model of compressed breasts by overcoming detector size bias, removing the nipple and non-mammary tissue, pairing the CC and MLO views from a single breast, and incorporating the pectoralis major muscle contour into the model. The outer breast shapes in 931 paired CC and MLO mammograms were automatically detected with an in-house developed segmentation algorithm. From these shapes three generic models (CC-only, MLO-only, and joint CC/MLO) with linearly independent components were constructed via principal component analysis (PCA). The ability of the models to represent mammograms not used for PCA was tested via leave-one-out cross-validation, by measuring the average distance error (ADE). The individual models based on six components were found to depict breast shapes with accuracy (mean ADE-CC = 0.81 mm, ADE-MLO = 1.64 mm, ADE-Pectoralis = 1.61 mm), outperforming the joint CC/MLO model (P ≤ 0.001). The joint model based on 12 principal components contains 99.5% of the total variance of the data, and can be used to generate new clinically realistic paired CC and MLO breast shapes. This is achieved by generating random sets of 12 principal components, following the Gaussian distributions of the histograms of each component, which were obtained from the component values determined from the images in the mammography database used. Our joint CC/MLO model can successfully generate paired CC and MLO view shapes of the same simulated breast, while the individual models can be used to represent with high accuracy clinical acquired mammograms with a small set of parameters. This is the first

  5. Age-dependent Fourier model of the shape of the isolated ex vivo human crystalline lens.

    Science.gov (United States)

    Urs, Raksha; Ho, Arthur; Manns, Fabrice; Parel, Jean-Marie

    2010-06-01

    To develop an age-dependent mathematical model of the zero-order shape of the isolated ex vivo human crystalline lens, using one mathematical function, that can be subsequently used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Profiles of whole isolated human lenses (n=30) aged 20-69, were measured from shadow-photogrammetric images. The profiles were fit to a 10th-order Fourier series consisting of cosine functions in polar-co-ordinate system that included terms for tilt and decentration. The profiles were corrected using these terms and processed in two ways. In the first, each lens was fit to a 10th-order Fourier series to obtain thickness and diameter, while in the second, all lenses were simultaneously fit to a Fourier series equation that explicitly include linear terms for age to develop an age-dependent mathematical model for the whole lens shape. Thickness and diameter obtained from Fourier series fits exhibited high correlation with manual measurements made from shadow-photogrammetric images. The root-mean-squared-error of the age-dependent fit was 205 microm. The age-dependent equations provide a reliable lens model for ages 20-60 years. The contour of the whole human crystalline lens can be modeled with a Fourier series. Shape obtained from the age-dependent model described in this paper can be used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  6. Estimating Small-Body Gravity Field from Shape Model and Navigation Data

    Science.gov (United States)

    Park, Ryan S.; Werner, Robert A.; Bhaskaran, Shyam

    2008-01-01

    This paper presents a method to model the external gravity field and to estimate the internal density variation of a small-body. We first discuss the modeling problem, where we assume the polyhedral shape and internal density distribution are given, and model the body interior using finite elements definitions, such as cubes and spheres. The gravitational attractions computed from these approaches are compared with the true uniform-density polyhedral attraction and the level of accuracies are presented. We then discuss the inverse problem where we assume the body shape, radiometric measurements, and a priori density constraints are given, and estimate the internal density variation by estimating the density of each finite element. The result shows that the accuracy of the estimated density variation can be significantly improved depending on the orbit altitude, finite-element resolution, and measurement accuracy.

  7. Ultrafast method of calculating the dynamic spectral line shapes for integrated modelling of plasmas

    International Nuclear Information System (INIS)

    Lisitsa, V.S.

    2009-01-01

    An ultrafast code for spectral line shape calculations is presented to be used in the integrated modelling of plasmas. The code is based on the close analogy between two mechanisms: (i) Dicke narrowing of the Doppler-broadened spectral lines and (ii) transition from static to impact regime in the Stark broadening. The analogy makes it possible to describe the dynamic Stark broadening in terms of an analytical functional of the static line shape. A comparison of new method with the widely used Frequency Fluctuating Method (FFM) developed by the Marseille University group (B. Talin, R. Stamm, et al.) shows good agreement, with the new method being faster than the standard FFM by nearly two orders of magnitude. The method proposed may significantly simplify the radiation transport modeling and opens new possibilities for integrated modeling of the edge and divertor plasma in tokamaks. (author)

  8. Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

    Science.gov (United States)

    Oguz, Sirri

    2010-01-01

    The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

  9. A case of pathological rib fractures: focal osteolysis or osteoporosis?

    Science.gov (United States)

    Vrbanić, T S L; Novak, S; Sestan, B; Tudor, A; Gulan, G

    2008-03-01

    This paper reports on a unique, previously unreported, successful outcome in the case of a patient with focal osteolytic lesions of the ribs as a first sign of osteoporosis. The lesions were detected by chance after acute cough-induced rib fractures were seen on plain chest radiographs. The diagnosis had to be approached as a diagnosis of exclusion since known causes of the osteolytic process had to be eliminated. The authors describe multiple focal osteolytic lesions with rib fractures appearing in a pattern that could be confused with metastases. Laboratory results were normal. Final diagnosis was based on plain radiography, bone scan and bone densitometry. Pharmacomedical treatments for osteoporosis were applied. The patient was observed between the year 2000 and 2005. Five years later radiological and bone scintigraphy revealed resolution of the lesion. We conclude that osteoporosis should be included in the differential diagnosis of asymptomatic focal osteolysis of the ribs with rib fractures as a complication of acute cough. The case suggests that focal osteolytic lesions of the ribs may regress over time and become scintigraphically inactive.

  10. Rib fractures in trauma patients: does operative fixation improve outcome?

    Science.gov (United States)

    Majak, Peter; Næss, Pål A

    2016-12-01

    Renewed interest in surgical fixation of rib fractures has emerged. However, conservative treatment is still preferred at most surgical departments. We wanted to evaluate whether operative treatment of rib fractures may benefit severely injured patients. Several studies report a reduction in mechanical ventilation time, ICU length of stay (LOS), hospital LOS, pneumonia, need for tracheostomy, pain and costs in operatively treated patients with multiple rib fractures compared with patients treated nonoperatively. Although patient selection and timing of the operation seem crucial for successful outcome, no consensus exists. Mortality reduction has only been shown in a few studies. Most studies are retrospective cohort and case-control studies. Only four randomized control trials exist. Conservative treatment, consisting of respiratory assistance and pain control, is still the treatment of choice in the vast majority of patients with multiple rib fractures. In selected patients, operative fixation of fractured ribs within 72 h postinjury may lead to better outcome. More randomized control trials are needed to further determine who benefits from surgical fixation of rib fractures.

  11. Numerical study on human model shape and grid dependency for indoor thermal comfort evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jin Won; Choi, Yun Ho [Ajou University, Suwon (Korea, Republic of); Park, Jae Hong [LIG Nexl Co. Ltd, Seongnam (Korea, Republic of)

    2013-02-15

    Various computer-simulated person (CSP) models have been used to represent occupants in indoor airflow simulations using computational fluid dynamics (CFD). Despite the capability of CFD to predict temperature and velocity fields in an automotive cabin or a room in a building, it is more difficult to evaluate the degree of thermal comfort considered by the CSP models. Up to now, the shapes of CSP models and their grid characteristics have not been studied for the evaluation of indoor thermal comfort. In this paper, the effects of the human model's shape and the physical characteristics of the grids are studied. The FLUENT code is used for analysis, and the predicted mean vote (PMV), predicted percentage dissatisfied (PPD), and equivalent homogeneous temperature (EHT) values are used for the evaluation and comparison of thermal comfort. The computational results show that the CSP shape and grid features do not affect the global flow fields or the evaluations of PMV and PPD. However, more precise results are obtained from the evaluation of thermal comfort by EHT when detailed human models with a prism grid are used.

  12. Numerical study on human model shape and grid dependency for indoor thermal comfort evaluation

    International Nuclear Information System (INIS)

    Seo, Jin Won; Choi, Yun Ho; Park, Jae Hong

    2013-01-01

    Various computer-simulated person (CSP) models have been used to represent occupants in indoor airflow simulations using computational fluid dynamics (CFD). Despite the capability of CFD to predict temperature and velocity fields in an automotive cabin or a room in a building, it is more difficult to evaluate the degree of thermal comfort considered by the CSP models. Up to now, the shapes of CSP models and their grid characteristics have not been studied for the evaluation of indoor thermal comfort. In this paper, the effects of the human model's shape and the physical characteristics of the grids are studied. The FLUENT code is used for analysis, and the predicted mean vote (PMV), predicted percentage dissatisfied (PPD), and equivalent homogeneous temperature (EHT) values are used for the evaluation and comparison of thermal comfort. The computational results show that the CSP shape and grid features do not affect the global flow fields or the evaluations of PMV and PPD. However, more precise results are obtained from the evaluation of thermal comfort by EHT when detailed human models with a prism grid are used.

  13. Lateral Penumbra Modelling Based Leaf End Shape Optimization for Multileaf Collimator in Radiotherapy

    Directory of Open Access Journals (Sweden)

    Dong Zhou

    2016-01-01

    Full Text Available Lateral penumbra of multileaf collimator plays an important role in radiotherapy treatment planning. Growing evidence has revealed that, for a single-focused multileaf collimator, lateral penumbra width is leaf position dependent and largely attributed to the leaf end shape. In our study, an analytical method for leaf end induced lateral penumbra modelling is formulated using Tangent Secant Theory. Compared with Monte Carlo simulation and ray tracing algorithm, our model serves well the purpose of cost-efficient penumbra evaluation. Leaf ends represented in parametric forms of circular arc, elliptical arc, Bézier curve, and B-spline are implemented. With biobjective function of penumbra mean and variance introduced, genetic algorithm is carried out for approximating the Pareto frontier. Results show that for circular arc leaf end objective function is convex and convergence to optimal solution is guaranteed using gradient based iterative method. It is found that optimal leaf end in the shape of Bézier curve achieves minimal standard deviation, while using B-spline minimum of penumbra mean is obtained. For treatment modalities in clinical application, optimized leaf ends are in close agreement with actual shapes. Taken together, the method that we propose can provide insight into leaf end shape design of multileaf collimator.

  14. Human vision model in relation to characteristics of shapes for the Mach band effect.

    Science.gov (United States)

    Wu, Bo-Wen; Fang, Yi-Chin

    2015-10-01

    For human vision to recognize the contours of objects means that, as the contrast variation at the object's edges increases, so will the Mach band effect of human vision. This paper more deeply investigates the relationship between changes in the contours of an object and the Mach band effect of human vision. Based on lateral inhibition and the Mach band effect, we studied subjects' eyes as they watched images of different shapes under a fixed brightness at 34  cd/m2, with changes of contrast and spatial frequency. Three types of display were used: a television, a computer monitor, and a projector. For each display used, we conducted a separate experiment for each shape. Although the maximum values for the contrast sensitivity function curves of the displays were different, their variations were minimal. As the spatial frequency changed, the diminishing effect of the different lines also was minimal. However, as the shapes at the contour intersections were modified by the Mach band effect, a greater degree of variation occurred. In addition, as the spatial frequency at a contour intersection increased, the Mach band effect became lower, along with changes in the corresponding contrast sensitivity function curve. Our experimental results on the characteristics of human vision have led to what we believe is a new vision model based on tests with different shapes. This new model may be used for future development and implementation of an artificial vision system.

  15. Lateral Penumbra Modelling Based Leaf End Shape Optimization for Multileaf Collimator in Radiotherapy.

    Science.gov (United States)

    Zhou, Dong; Zhang, Hui; Ye, Peiqing

    2016-01-01

    Lateral penumbra of multileaf collimator plays an important role in radiotherapy treatment planning. Growing evidence has revealed that, for a single-focused multileaf collimator, lateral penumbra width is leaf position dependent and largely attributed to the leaf end shape. In our study, an analytical method for leaf end induced lateral penumbra modelling is formulated using Tangent Secant Theory. Compared with Monte Carlo simulation and ray tracing algorithm, our model serves well the purpose of cost-efficient penumbra evaluation. Leaf ends represented in parametric forms of circular arc, elliptical arc, Bézier curve, and B-spline are implemented. With biobjective function of penumbra mean and variance introduced, genetic algorithm is carried out for approximating the Pareto frontier. Results show that for circular arc leaf end objective function is convex and convergence to optimal solution is guaranteed using gradient based iterative method. It is found that optimal leaf end in the shape of Bézier curve achieves minimal standard deviation, while using B-spline minimum of penumbra mean is obtained. For treatment modalities in clinical application, optimized leaf ends are in close agreement with actual shapes. Taken together, the method that we propose can provide insight into leaf end shape design of multileaf collimator.

  16. Lateral Penumbra Modelling Based Leaf End Shape Optimization for Multileaf Collimator in Radiotherapy

    Science.gov (United States)

    Zhou, Dong; Zhang, Hui; Ye, Peiqing

    2016-01-01

    Lateral penumbra of multileaf collimator plays an important role in radiotherapy treatment planning. Growing evidence has revealed that, for a single-focused multileaf collimator, lateral penumbra width is leaf position dependent and largely attributed to the leaf end shape. In our study, an analytical method for leaf end induced lateral penumbra modelling is formulated using Tangent Secant Theory. Compared with Monte Carlo simulation and ray tracing algorithm, our model serves well the purpose of cost-efficient penumbra evaluation. Leaf ends represented in parametric forms of circular arc, elliptical arc, Bézier curve, and B-spline are implemented. With biobjective function of penumbra mean and variance introduced, genetic algorithm is carried out for approximating the Pareto frontier. Results show that for circular arc leaf end objective function is convex and convergence to optimal solution is guaranteed using gradient based iterative method. It is found that optimal leaf end in the shape of Bézier curve achieves minimal standard deviation, while using B-spline minimum of penumbra mean is obtained. For treatment modalities in clinical application, optimized leaf ends are in close agreement with actual shapes. Taken together, the method that we propose can provide insight into leaf end shape design of multileaf collimator. PMID:27110274

  17. RIB production with photofission of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Oganessian, Yu.Ts. E-mail: oganessian@flnr.jinr.ru; Dmitriev, S.N.; Kliman, J.; Maslov, O.A.; Starodub, G.Ya.; Belov, A.G.; Tretiakova, S.P

    2002-04-22

    The process of uranium photofission with electron beams of 20-50 MeV is considered in terms of the production of fission fragments. It is shown that in the interaction between an electron beam (25 MeV in energy and 20 {mu}A in intensity), produced by a compact accelerator of the microtron type, and a uranium target of about 40 g/cm{sup 2} in thickness, an average of 1.5x10{sup 11} fission events per second is generated. According to the calculations and test experiments, this corresponds to the yield of {sup 132}Sn and {sup 142}Xe isotopes of approximately 2x10{sup 9}/s. The results of experiments on the optimal design of the U-target are presented. Problems are discussed connected with the separation of isotopes and isobars for their further acceleration up to energies of 5-18 MeV A. The photofission reactions of a heavy nucleus are compared with other methods of RIB production of medium mass nuclei.

  18. Hybrid rib-slot-rib plasmonic waveguide with deep-subwavelength mode confinement and long propagation length

    Directory of Open Access Journals (Sweden)

    Kai Zheng

    2016-08-01

    Full Text Available We propose a hybrid plasmonic waveguide where a combined rib-slot-rib structure is added on the metal substrate within a low-index gap region. The optical properties of the quasi-TM fundamental mode are numerically calculated using the finite element method. Compared to the traditional hybrid plasmonic waveguide, our designed waveguiding structure can support modes with tighter confinement and longer propagation length, by properly adjusting the geometry of the rib-slot-rib structure and the gap height. In details, it can provide the hybrid mode with mode area λ2/12000 and reasonable propagation distance 23.78 μm, simultaneously. Its excellent optical performance can facilitate potential applications in ultra-compact nanophotonic devices and circuits.

  19. Learning a generative model of images by factoring appearance and shape.

    Science.gov (United States)

    Le Roux, Nicolas; Heess, Nicolas; Shotton, Jamie; Winn, John

    2011-03-01

    Computer vision has grown tremendously in the past two decades. Despite all efforts, existing attempts at matching parts of the human visual system's extraordinary ability to understand visual scenes lack either scope or power. By combining the advantages of general low-level generative models and powerful layer-based and hierarchical models, this work aims at being a first step toward richer, more flexible models of images. After comparing various types of restricted Boltzmann machines (RBMs) able to model continuous-valued data, we introduce our basic model, the masked RBM, which explicitly models occlusion boundaries in image patches by factoring the appearance of any patch region from its shape. We then propose a generative model of larger images using a field of such RBMs. Finally, we discuss how masked RBMs could be stacked to form a deep model able to generate more complicated structures and suitable for various tasks such as segmentation or object recognition.

  20. Quantitative model for the generic 3D shape of ICMEs at 1 AU

    Science.gov (United States)

    Démoulin, P.; Janvier, M.; Masías-Meza, J. J.; Dasso, S.

    2016-10-01

    Context. Interplanetary imagers provide 2D projected views of the densest plasma parts of interplanetary coronal mass ejections (ICMEs), while in situ measurements provide magnetic field and plasma parameter measurements along the spacecraft trajectory, that is, along a 1D cut. The data therefore only give a partial view of the 3D structures of ICMEs. Aims: By studying a large number of ICMEs, crossed at different distances from their apex, we develop statistical methods to obtain a quantitative generic 3D shape of ICMEs. Methods: In a first approach we theoretically obtained the expected statistical distribution of the shock-normal orientation from assuming simple models of 3D shock shapes, including distorted profiles, and compared their compatibility with observed distributions. In a second approach we used the shock normal and the flux rope axis orientations together with the impact parameter to provide statistical information across the spacecraft trajectory. Results: The study of different 3D shock models shows that the observations are compatible with a shock that is symmetric around the Sun-apex line as well as with an asymmetry up to an aspect ratio of around 3. Moreover, flat or dipped shock surfaces near their apex can only be rare cases. Next, the sheath thickness and the ICME velocity have no global trend along the ICME front. Finally, regrouping all these new results and those of our previous articles, we provide a quantitative ICME generic 3D shape, including the global shape of the shock, the sheath, and the flux rope. Conclusions: The obtained quantitative generic ICME shape will have implications for several aims. For example, it constrains the output of typical ICME numerical simulations. It is also a base for studying the transport of high-energy solar and cosmic particles during an ICME propagation as well as for modeling and forecasting space weather conditions near Earth.

  1. A Semianalytical Model for Pumping Tests in Finite Heterogeneous Confined Aquifers With Arbitrarily Shaped Boundary

    Science.gov (United States)

    Wang, Lei; Dai, Cheng; Xue, Liang

    2018-04-01

    This study presents a Laplace-transform-based boundary element method to model the groundwater flow in a heterogeneous confined finite aquifer with arbitrarily shaped boundaries. The boundary condition can be Dirichlet, Neumann or Robin-type. The derived solution is analytical since it is obtained through the Green's function method within the domain. However, the numerical approximation is required on the boundaries, which essentially renders it a semi-analytical solution. The proposed method can provide a general framework to derive solutions for zoned heterogeneous confined aquifers with arbitrarily shaped boundary. The requirement of the boundary element method presented here is that the Green function must exist for a specific PDE equation. In this study, the linear equations for the two-zone and three-zone confined aquifers with arbitrarily shaped boundary is established in Laplace space, and the solution can be obtained by using any linear solver. Stehfest inversion algorithm can be used to transform it back into time domain to obtain the transient solution. The presented solution is validated in the two-zone cases by reducing the arbitrarily shaped boundaries to circular ones and comparing it with the solution in Lin et al. (2016, https://doi.org/10.1016/j.jhydrol.2016.07.028). The effect of boundary shape and well location on dimensionless drawdown in two-zone aquifers is investigated. Finally the drawdown distribution in three-zone aquifers with arbitrarily shaped boundary for constant-rate tests (CRT) and flow rate distribution for constant-head tests (CHT) are analyzed.

  2. Whole vertebral bone segmentation method with a statistical intensity-shape model based approach

    Science.gov (United States)

    Hanaoka, Shouhei; Fritscher, Karl; Schuler, Benedikt; Masutani, Yoshitaka; Hayashi, Naoto; Ohtomo, Kuni; Schubert, Rainer

    2011-03-01

    An automatic segmentation algorithm for the vertebrae in human body CT images is presented. Especially we focused on constructing and utilizing 4 different statistical intensity-shape combined models for the cervical, upper / lower thoracic and lumbar vertebrae, respectively. For this purpose, two previously reported methods were combined: a deformable model-based initial segmentation method and a statistical shape-intensity model-based precise segmentation method. The former is used as a pre-processing to detect the position and orientation of each vertebra, which determines the initial condition for the latter precise segmentation method. The precise segmentation method needs prior knowledge on both the intensities and the shapes of the objects. After PCA analysis of such shape-intensity expressions obtained from training image sets, vertebrae were parametrically modeled as a linear combination of the principal component vectors. The segmentation of each target vertebra was performed as fitting of this parametric model to the target image by maximum a posteriori estimation, combined with the geodesic active contour method. In the experimental result by using 10 cases, the initial segmentation was successful in 6 cases and only partially failed in 4 cases (2 in the cervical area and 2 in the lumbo-sacral). In the precise segmentation, the mean error distances were 2.078, 1.416, 0.777, 0.939 mm for cervical, upper and lower thoracic, lumbar spines, respectively. In conclusion, our automatic segmentation algorithm for the vertebrae in human body CT images showed a fair performance for cervical, thoracic and lumbar vertebrae.

  3. A model of shape memory materials with hierarchical twinning: statics and dynamics

    International Nuclear Information System (INIS)

    Saxena, A.; Bishop, A.R.; Wu, Y.; Lookman, T.

    1995-01-01

    We consider a model of shape memory materials in which hierarchical twinning near the habit plane (austenite-martensite interface) is a new and crucial ingredient. The model includes (1) a triple-well potential (φ 6 model) in local shear strain, (2) strain gradient terms up to second order in strain and fourth order in gradient, and (3) all symmetry allowed compositional fluctuation-induced strain gradient terms. The last term favors hierarchy which enables communication between macroscopic (cm) and microscopic (A) regions essential for shape memory. Hierarchy also stabilizes tweed formation (criss-cross patterns of twins). External stress or pressure modulates (''patterns'') the spacing of domain walls. Therefore the ''pattern'' is encoded in the modulated hierarchical variation of the depth and width of the twins. This hierarchy of length scales provides a related hierarchy of time scales and thus the possibility of non-exponential decay. The four processes of the complete shape memory cycle-write, record, erase and recall-are explained within this model. Preliminary results based on 2D molecular dynamics are shown for tweed and hierarchy formation. (orig.)

  4. PREDICTION OF BLOOD PATTERN IN S-SHAPED MODEL OF ARTERY UNDER NORMAL BLOOD PRESSURE

    Directory of Open Access Journals (Sweden)

    Mohd Azrul Hisham Mohd Adib

    2013-06-01

    Full Text Available Athletes are susceptible to a wide variety of traumatic and non-traumatic vascular injuries to the lower limb. This paper aims to predict the three-dimensional flow pattern of blood through an S-shaped geometrical artery model. This model has created by using Fluid Structure Interaction (FSI software. The modeling of the geometrical S-shaped artery is suitable for understanding the pattern of blood flow under constant normal blood pressure. In this study, a numerical method is used that works on the assumption that the blood is incompressible and Newtonian; thus, a laminar type of flow can be considered. The authors have compared the results with a previous study with FSI validation simulation. The validation and verification of the simulation studies is performed by comparing the maximum velocity at t = 0.4 s, because at this time, the blood accelerates rapidly. In addition, the resulting blood flow at various times, under the same boundary conditions in the S-shaped geometrical artery model, is presented. The graph shows that velocity increases linearly with time. Thus, it can be concluded that the flow of blood increases with respect to the pressure inside the body.

  5. Adaptive Shape Functions and Internal Mesh Adaptation for Modelling Progressive Failure in Adhesively Bonded Joints

    Science.gov (United States)

    Stapleton, Scott; Gries, Thomas; Waas, Anthony M.; Pineda, Evan J.

    2014-01-01

    Enhanced finite elements are elements with an embedded analytical solution that can capture detailed local fields, enabling more efficient, mesh independent finite element analysis. The shape functions are determined based on the analytical model rather than prescribed. This method was applied to adhesively bonded joints to model joint behavior with one element through the thickness. This study demonstrates two methods of maintaining the fidelity of such elements during adhesive non-linearity and cracking without increasing the mesh needed for an accurate solution. The first method uses adaptive shape functions, where the shape functions are recalculated at each load step based on the softening of the adhesive. The second method is internal mesh adaption, where cracking of the adhesive within an element is captured by further discretizing the element internally to represent the partially cracked geometry. By keeping mesh adaptations within an element, a finer mesh can be used during the analysis without affecting the global finite element model mesh. Examples are shown which highlight when each method is most effective in reducing the number of elements needed to capture adhesive nonlinearity and cracking. These methods are validated against analogous finite element models utilizing cohesive zone elements.

  6. A 3' UTR-derived non-coding RNA RibS increases expression of cfa and promotes biofilm formation of Salmonella enterica serovar Typhi.

    Science.gov (United States)

    Zhao, Xin; Liu, Rui; Tang, Hao; Osei-Adjei, George; Xu, Shungao; Zhang, Ying; Huang, Xinxiang

    2018-05-08

    Bacterial non-coding RNAs (ncRNAs) are widely studied and found to play important roles in regulating various cellular processes. Recently, many ncRNAs have been discovered to be transcribed or processed from 3' untranslated regions (3' UTRs). Here we reported a novel 3' UTR-derived ncRNA, RibS, which could influence biofilm formation of Salmonella enterica serovar Typhi (S. Typhi). RibS was confirmed to be a ∼700 nt processed product produced by RNase III-catalyzed cleavage from the 3' UTR of riboflavin synthase subunit alpha mRNA, RibE. Overexpression of RibS increased the expression of the cyclopropane fatty acid synthase gene, cfa, which was located at the antisense strand. Biofilm formation of S. Typhi was enhanced by overexpressing RibS both in the wild type strain and cfa deletion mutant. Deletion of cfa attenuated biofilm formation of S. Typhi, while complementation of cfa partly restored the phenotype. Moreover, overexpressing cfa enhanced the biofilm formation of S. Typhi. In summary, RibS has been identified as a novel ncRNA derived from the 3' UTR of RibE that promotes biofilm formation of S. Typhi, and it appears to do so, at least in part, by increasing the expression of cfa. Copyright © 2018 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  7. Potential Benefits of Rib Fracture Fixation in Patients with Flail Chest and Multiple Non-flail Rib Fractures.

    Science.gov (United States)

    Qiu, Meiguang; Shi, Zhanjun; Xiao, Jun; Zhang, Xuming; Ling, Shishui; Ling, Hao

    2016-12-01

    The purpose of this study is to evaluate the potential benefits of rib fracture fixation in patients with flail chest and multiple non-flail rib fractures versus conventional treatment modalities. A retrospective reviewed study compared 86 cases which received surgical treatment between June 2009 and May 2013 to 76 cases which received conservative treatment between January 2006 and May 2009. The patients were divided into the flail chest ( n  = 38) and multiple non-flail rib fracture groups ( n  = 124). In the flail chest group, the mechanical ventilation time, ICU monitoring time, tracheostomies, thoracic deformity, and impaired pulmonary function and return to full-time employment were compared. In the multiple non-flail rib fracture group, fracture healing, visual analog scale (VAS) pain score, inpatient length of stay, atelectatic, pulmonary complications, and normal activity-returning time were compared. Patients in the flail chest operative fixation group had significantly shorter ICU stay, decreased ventilator requirements, fewer tracheostomies, less thoracic deformity and impaired pulmonary function, and more returned to full-time employment. Patients in the multiple non-flail rib fracture operative fixation had shorter hospital stay, less pain, earlier return to normal activity, more fracture healing, less atelectasis, and fewer pulmonary infections. This study demonstrates the potential benefits of surgical stabilization of flail chest and multiple non-flail rib fractures with plate fixation. When compared with conventional conservative management, operatively managed patients demonstrated improved clinical outcomes.

  8. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

    Science.gov (United States)

    Wu, Hau-Tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong

    2016-01-01

    We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

  9. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

    Directory of Open Access Journals (Sweden)

    Hau-Tieng Wu

    Full Text Available We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

  10. Electropolishing on single-cell: (TESLA, Reentrant and Low Loss shapes) Comsol modelling

    International Nuclear Information System (INIS)

    Bruchon, M.

    2007-01-01

    In the framework of improvement of cavity electropolishing, modelling permits to evaluate some parameters not easily accessible by experiments and can also help us to guide them. Different laboratories (DESY, Fermilab) work on electro or chemical polishing modelling with different approaches and softwares. At CEA Saclay, COMSOL software is used to model horizontal electropolishing of cavity in two dimensions. The goal of this study has been motivated by improvement of our electropolishing setup by modifying the arrival of the acid. The influence of a protuberant cathode has been evaluated and compared for different shapes of single cell cavities: TESLA, ILC Low Loss (LL ILC ), and ILC Reentrant (RE ILC ). (author)

  11. A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

    International Nuclear Information System (INIS)

    Wada, Ken; Hyodo, Toshio

    2013-01-01

    Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.

  12. A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

    Science.gov (United States)

    Wada, Ken; Hyodo, Toshio

    2013-06-01

    Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.

  13. A phenomenological two-phase constitutive model for porous shape memory alloys

    KAUST Repository

    El Sayed, Tamer S.

    2012-07-01

    We present a two-phase constitutive model for pseudoelastoplastic behavior of porous shape memory alloys (SMAs). The model consists of a dense SMA phase and a porous plasticity phase. The overall response of the porous SMA is obtained by a weighted average of responses of individual phases. Based on the chosen constitutive model parameters, the model incorporates the pseudoelastic and pseudoplastic behavior simultaneously (commonly reported for porous SMAs) as well as sequentially (i.e. dense SMAs; pseudoelastic deformation followed by the pseudoplastic deformation until failure). The presented model also incorporates failure due to the deviatoric (shear band formation) and volumetric (void growth and coalescence) plastic deformation. The model is calibrated by representative volume elements (RVEs) with different sizes of spherical voids that are solved by unit cell finite element calculations. The overall response of the model is tested against experimental results from literature. Finally, application of the presented constitutive model has been presented by performing finite element simulations of the deformation and failure in unaixial dog-bone shaped specimen and compact tension (CT) test specimen. Results show a good agreement with the experimental data reported in the literature. © 2012 Elsevier B.V. All rights reserved.

  14. Use of Image Based Modelling for Documentation of Intricately Shaped Objects

    Science.gov (United States)

    Marčiš, M.; Barták, P.; Valaška, D.; Fraštia, M.; Trhan, O.

    2016-06-01

    In the documentation of cultural heritage, we can encounter three dimensional shapes and structures which are complicated to measure. Such objects are for example spiral staircases, timber roof trusses, historical furniture or folk costume where it is nearly impossible to effectively use the traditional surveying or the terrestrial laser scanning due to the shape of the object, its dimensions and the crowded environment. The actual methods of digital photogrammetry can be very helpful in such cases with the emphasis on the automated processing of the extensive image data. The created high resolution 3D models and 2D orthophotos are very important for the documentation of architectural elements and they can serve as an ideal base for the vectorization and 2D drawing documentation. This contribution wants to describe the various usage of image based modelling in specific interior spaces and specific objects. The advantages and disadvantages of the photogrammetric measurement of such objects in comparison to other surveying methods are reviewed.

  15. Bohr model description of the critical point for the first order shape phase transition

    Science.gov (United States)

    Budaca, R.; Buganu, P.; Budaca, A. I.

    2018-01-01

    The critical point of the shape phase transition between spherical and axially deformed nuclei is described by a collective Bohr Hamiltonian with a sextic potential having simultaneous spherical and deformed minima of the same depth. The particular choice of the potential as well as the scaled and decoupled nature of the total Hamiltonian leads to a model with a single free parameter connected to the height of the barrier which separates the two minima. The solutions are found through the diagonalization in a basis of Bessel functions. The basis is optimized for each value of the free parameter by means of a boundary deformation which assures the convergence of the solutions for a fixed basis dimension. Analyzing the spectral properties of the model, as a function of the barrier height, revealed instances with shape coexisting features which are considered for detailed numerical applications.

  16. Bohr model description of the critical point for the first order shape phase transition

    Directory of Open Access Journals (Sweden)

    R. Budaca

    2018-01-01

    Full Text Available The critical point of the shape phase transition between spherical and axially deformed nuclei is described by a collective Bohr Hamiltonian with a sextic potential having simultaneous spherical and deformed minima of the same depth. The particular choice of the potential as well as the scaled and decoupled nature of the total Hamiltonian leads to a model with a single free parameter connected to the height of the barrier which separates the two minima. The solutions are found through the diagonalization in a basis of Bessel functions. The basis is optimized for each value of the free parameter by means of a boundary deformation which assures the convergence of the solutions for a fixed basis dimension. Analyzing the spectral properties of the model, as a function of the barrier height, revealed instances with shape coexisting features which are considered for detailed numerical applications.

  17. Mathematical modelling of the viable epidermis: impact of cell shape and vertical arrangement

    KAUST Repository

    Wittum, Rebecca

    2017-12-07

    In-silico methods are valuable tools for understanding the barrier function of the skin. The key benefit is that mathematical modelling allows the interplay between cell shape and function to be elucidated. This study focuses on the viable (living) epidermis. For this region, previous works suggested a diffusion model and an approximation of the cells by hexagonal prisms. The work at hand extends this in three ways. First, the extracellular space is treated with full spatial resolution. This induces a decrease of permeability by about 10%. Second, cells of tetrakaidecahedral shape are considered, in addition to the original hexagonal prisms. For both cell types, the resulting membrane permeabilities are compared. Third, for the first time, the influence of cell stacking in the vertical direction is considered. This is particularly important for the stratum granulosum, where tight junctions are present.

  18. Effects of source shape on the numerical aperture factor with a geometrical-optics model.

    Science.gov (United States)

    Wan, Der-Shen; Schmit, Joanna; Novak, Erik

    2004-04-01

    We study the effects of an extended light source on the calibration of an interference microscope, also referred to as an optical profiler. Theoretical and experimental numerical aperture (NA) factors for circular and linear light sources along with collimated laser illumination demonstrate that the shape of the light source or effective aperture cone is critical for a correct NA factor calculation. In practice, more-accurate results for the NA factor are obtained when a linear approximation to the filament light source shape is used in a geometric model. We show that previously measured and derived NA factors show some discrepancies because a circular rather than linear approximation to the filament source was used in the modeling.

  19. Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

    Directory of Open Access Journals (Sweden)

    Natalya Pya

    2016-02-01

    Full Text Available Background: Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height (dbh can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter (h-d models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods: We develop unconstrained generalized additive models (GAM and shape constrained generalized additive models (SCAM for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results: Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand. The definition of constraints leads only to marginal or minor decline in the model statistics like AIC. An observed structured spatial trend in tree height is modelled via 2-dimensional surface

  20. Optimal input shaping for Fisher identifiability of control-oriented lithium-ion battery models

    Science.gov (United States)

    Rothenberger, Michael J.

    This dissertation examines the fundamental challenge of optimally shaping input trajectories to maximize parameter identifiability of control-oriented lithium-ion battery models. Identifiability is a property from information theory that determines the solvability of parameter estimation for mathematical models using input-output measurements. This dissertation creates a framework that exploits the Fisher information metric to quantify the level of battery parameter identifiability, optimizes this metric through input shaping, and facilitates faster and more accurate estimation. The popularity of lithium-ion batteries is growing significantly in the energy storage domain, especially for stationary and transportation applications. While these cells have excellent power and energy densities, they are plagued with safety and lifespan concerns. These concerns are often resolved in the industry through conservative current and voltage operating limits, which reduce the overall performance and still lack robustness in detecting catastrophic failure modes. New advances in automotive battery management systems mitigate these challenges through the incorporation of model-based control to increase performance, safety, and lifespan. To achieve these goals, model-based control requires accurate parameterization of the battery model. While many groups in the literature study a variety of methods to perform battery parameter estimation, a fundamental issue of poor parameter identifiability remains apparent for lithium-ion battery models. This fundamental challenge of battery identifiability is studied extensively in the literature, and some groups are even approaching the problem of improving the ability to estimate the model parameters. The first approach is to add additional sensors to the battery to gain more information that is used for estimation. The other main approach is to shape the input trajectories to increase the amount of information that can be gained from input

  1. A microscopically motivated constitutive model for shape memory alloys: Formulation, analysis and computations

    Czech Academy of Sciences Publication Activity Database

    Frost, Miroslav; Benešová, B.; Sedlák, P.

    2016-01-01

    Roč. 21, č. 3 (2016), s. 358-382 ISSN 1081-2865 R&D Projects: GA ČR GA13-13616S; GA ČR GAP201/10/0357 Institutional support: RVO:61388998 Keywords : shape memory alloys * constitutive model * generalized standard materials * dissipation * energetic solution Subject RIV: BA - General Mathematics Impact factor: 2.953, year: 2016 http://mms.sagepub.com/content/21/3/358

  2. Shape optimization for Navier-Stokes equations with algebraic turbulence model : numerical analysis and computation

    Czech Academy of Sciences Publication Activity Database

    Haslinger, J.; Stebel, Jan

    2011-01-01

    Roč. 63, č. 2 (2011), s. 277-308 ISSN 0095-4616 R&D Projects: GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : optimal shape design * paper machine headbox * incompressible non-Newtonian fluid * algebraic turbulence model Subject RIV: BA - General Mathematics Impact factor: 0.952, year: 2011 http://link.springer.com/article/10.1007%2Fs00245-010-9121-x

  3. Self assembly of rectangular shapes on concentration programming and probabilistic tile assembly models.

    Science.gov (United States)

    Kundeti, Vamsi; Rajasekaran, Sanguthevar

    2012-06-01

    Efficient tile sets for self assembling rectilinear shapes is of critical importance in algorithmic self assembly. A lower bound on the tile complexity of any deterministic self assembly system for an n × n square is [Formula: see text] (inferred from the Kolmogrov complexity). Deterministic self assembly systems with an optimal tile complexity have been designed for squares and related shapes in the past. However designing [Formula: see text] unique tiles specific to a shape is still an intensive task in the laboratory. On the other hand copies of a tile can be made rapidly using PCR (polymerase chain reaction) experiments. This led to the study of self assembly on tile concentration programming models. We present two major results in this paper on the concentration programming model. First we show how to self assemble rectangles with a fixed aspect ratio ( α:β ), with high probability, using Θ( α + β ) tiles. This result is much stronger than the existing results by Kao et al. (Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008) and Doty (Randomized self-assembly for exact shapes. In: proceedings of the 50th annual IEEE symposium on foundations of computer science (FOCS), IEEE, Atlanta. pp 85-94, 2009)-which can only self assembly squares and rely on tiles which perform binary arithmetic. On the other hand, our result is based on a technique called staircase sampling . This technique eliminates the need for sub-tiles which perform binary arithmetic, reduces the constant in the asymptotic bound, and eliminates the need for approximate frames (Kao et al. Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008). Our second result applies staircase sampling on the equimolar concentration programming model (The tile complexity of linear assemblies. In: proceedings of the 36th international colloquium automata, languages and programming: Part I on ICALP '09, Springer-Verlag, pp 235

  4. Analytical model for shape anisotropy in thin-film nanostructured arrays: Interaction effects

    International Nuclear Information System (INIS)

    Alvarez-Sanchez, R.; Costa-Kraemer, J.L.; Briones, F.

    2006-01-01

    When reducing the size of array elements and interelement separations to the nanoscale, long-range magnetostatic interactions become important. A methodology that extends the study of conventional single-element magnetostatics is presented, adding the effect of stacking nanoelements into close proximity in arrays and the consequent interaction effects. This would be very time consuming to model by micromagnetic simulations that are also very vulnerable to artifacts due to cell or boundary condition selection. The proposed method considers an analytical expression valid for short interelement separations and not very costly to evaluate by computational means. This approach allows the quantitative study of shape anisotropy in non-square-shaped arrays. It is also shown how it can be used to find anisotropy compensation conditions, where an anisotropy due to a magnetic element shape can be compensated by the shape anisotropy due to the array. The obtained results can be used to establish a criterion for the minimum number of elements to be considered for a micromagnetic simulation of an array to be realistic depending on the element size and separation

  5. Vibration mode and vibration shape under excitation of a three phase model transformer core

    Science.gov (United States)

    Okabe, Seiji; Ishigaki, Yusuke; Omura, Takeshi

    2018-04-01

    Structural vibration characteristics and vibration shapes under three-phase excitation of a archetype transformer core were investigated to consider their influences on transformer noise. Acoustic noise and vibration behavior were measured in a three-limb model transformer core. Experimental modal analysis by impact test was performed. The vibration shapes were measured by a laser scanning vibrometer at different exciting frequencies. Vibration amplitude of the core in out-of-plane direction were relatively larger than those in other two in-plane directions. It was consistent with the result that the frequency response function of the core in out-of-plane direction was larger by about 20 dB or more than those in in-plane directions. There were many vibration modes having bending deformation of limbs in out-of-plane direction. The vibration shapes of the core when excited at 50 Hz and 60 Hz were almost the same because the fundamental frequencies of the vibration were not close to the resonance frequencies. When excitation frequency was 69 Hz which was half of one of the resonance frequencies, the vibration shape changed to the one similar to the resonance vibration mode. Existence of many vibration modes in out-of-plane direction of the core was presumed to be a reason why frequency characteristics of magnetostriction and transformer noise do not coincide.

  6. Automatic Sex Determination of Skulls Based on a Statistical Shape Model

    Directory of Open Access Journals (Sweden)

    Li Luo

    2013-01-01

    Full Text Available Sex determination from skeletons is an important research subject in forensic medicine. Previous skeletal sex assessments are through subjective visual analysis by anthropologists or metric analysis of sexually dimorphic features. In this work, we present an automatic sex determination method for 3D digital skulls, in which a statistical shape model for skulls is constructed, which projects the high-dimensional skull data into a low-dimensional shape space, and Fisher discriminant analysis is used to classify skulls in the shape space. This method combines the advantages of metrical and morphological methods. It is easy to use without professional qualification and tedious manual measurement. With a group of Chinese skulls including 127 males and 81 females, we choose 92 males and 58 females to establish the discriminant model and validate the model with the other skulls. The correct rate is 95.7% and 91.4% for females and males, respectively. Leave-one-out test also shows that the method has a high accuracy.

  7. Aircraft Segmentation in SAR Images Based on Improved Active Shape Model

    Science.gov (United States)

    Zhang, X.; Xiong, B.; Kuang, G.

    2018-04-01

    In SAR image interpretation, aircrafts are the important targets arousing much attention. However, it is far from easy to segment an aircraft from the background completely and precisely in SAR images. Because of the complex structure, different kinds of electromagnetic scattering take place on the aircraft surfaces. As a result, aircraft targets usually appear to be inhomogeneous and disconnected. It is a good idea to extract an aircraft target by the active shape model (ASM), since combination of the geometric information controls variations of the shape during the contour evolution. However, linear dimensionality reduction, used in classic ACM, makes the model rigid. It brings much trouble to segment different types of aircrafts. Aiming at this problem, an improved ACM based on ISOMAP is proposed in this paper. ISOMAP algorithm is used to extract the shape information of the training set and make the model flexible enough to deal with different aircrafts. The experiments based on real SAR data shows that the proposed method achieves obvious improvement in accuracy.

  8. Understanding the Shape of the Land and Watersheds Using Simple Models in the Classroom

    Science.gov (United States)

    Gardiner, L.; Johnson, R.; Russell, R.; Bergman, J.; Genyuk, J.; Lagrave, M.

    2006-12-01

    Middle school students can gain essential understandings of the Earth and its processes in the classroom by making and manipulating simple models. While no substitute for field experiences, simple models made of easily-obtained materials can foster student understanding of natural environments. Through this collection of hands-on activities, students build and manipulate simple models that demonstrate (1) tectonic processes that shape the land, (2) the shape of the land surface, (3) how the shape of the land influences the distribution of waterways and watersheds, and (4) how the human communities within a watershed are interconnected through use of surface water. The classroom activities described in this presentation are available on Windows to the Universe (www.windows.ucar.edu), a project of the University Corporation for Atmospheric Research Office of Education and Outreach. Windows to the Universe, a long-standing Web resource supporting Earth and space science education, provides users with content about the Earth and space sciences at three levels (beginner, intermediate, and advanced) in English and Spanish. Approximately 80 hands-on classroom activities appropriate for K-12 classrooms are available within the teacher resources section of the Windows to the Universe.

  9. Prolonged pain and disability are common after rib fractures.

    Science.gov (United States)

    Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

    2013-05-01

    The contribution of rib fractures to prolonged pain and disability may be underappreciated and undertreated. Clinicians are traditionally taught that the pain and disability of rib fractures resolves in 6 to 8 weeks. This study was a prospective observation of 203 patients with rib fractures at a level 1 trauma center. Chest wall pain was evaluated by the McGill Pain Questionnaire (MPQ) pain rating index (PRI) and present pain intensity (PPI). Prolonged pain was defined as a PRI of 8 or more at 2 months after injury. Prolonged disability was defined as a decrease in 1 or more levels of work or functional status at 2 months after injury. Predictors of prolonged pain and disability were determined by multivariate analysis. One hundred forty-five male patients and 58 female patients with a mean injury severity score (ISS) of 20 (range, 1 to 59) had a mean of 5.4 rib fractures (range, 1 to 29). Forty-four (22%) patients had bilateral fractures, 15 (7%) had flail chest, and 92 (45%) had associated injury. One hundred eighty-seven patients were followed 2 months or more. One hundred ten (59%) patients had prolonged chest wall pain and 142 (76%) had prolonged disability. Among 111 patients with isolated rib fractures, 67 (64%) had prolonged chest wall pain and 69 (66%) had prolonged disability. MPQ PPI was predictive of prolonged pain (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4 to 2.5), and prolonged disability (OR, 2.2; 95% CI, 1.5 to 3.4). The presence of significant associated injuries was predictive of prolonged disability (OR, 5.9; 95% CI, 1.4 to 29). Prolonged chest wall pain is common, and the contribution of rib fractures to disability is greater than traditionally expected. Further investigation into more effective therapies that prevent prolonged pain and disability after rib fractures is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Vital capacity helps predict pulmonary complications after rib fractures.

    Science.gov (United States)

    Carver, Thomas W; Milia, David J; Somberg, Chloe; Brasel, Karen; Paul, Jasmeet

    2015-09-01

    Traumatic rib fractures are associated with significant morbidity. Vital capacity (VC) assesses pulmonary function; however, limited data link VC to patient outcomes. Our objective was to determine if VC predicted complications and disposition in patients with rib fractures. This is a retrospective chart review of all patients with fractured ribs admitted to a Level 1 trauma center during a 4-year period. Patients were excluded if no VC was performed within 48 hours of admission. Data collected included demographics, hospital/intensive care unit length of stay, epidural, discharge to home versus extended care facility, mortality, chest Abbreviated Injury Scale (AIS) score, Injury Severity Score (ISS), number of rib fractures, hemothorax/pneumothorax, presence of pulmonary contusion, presence of chest tube, chronic obstructive pulmonary disease, and average daily VC (percentage of predicted). Pulmonary complication was defined as pneumonia, need for intubation, new home O2 requirement, readmission for pulmonary issue, or intensive care unit transfer. Statistical analysis was performed using χ and multivariate logistic regression. Of 801 patients with rib fractures, 683 had VC performed within 48 hours. Average age was 53 years, median ISS was 13 (interquartile range, 9-18), and median length of stay was 5 days. Most (72%) were discharged home, and 26% went to extended care facility. Ten percent developed a pulmonary complication, and there were nine deaths. Every 10% increase in VC was associated with 36% decrease in likelihood of pulmonary complication. Patients with a VC greater than 50% had a significantly lower association of pulmonary complication (p = 0.017), and a VC of less than 30% was independently associated with pulmonary complication (odds ratio, 2.36). Patients with fractured ribs and VC of less than 30% have significant association for pulmonary complication. Higher VC is associated with lower likelihood of pulmonary complication. VC may help

  11. Effects of snow grain shape on climate simulations: sensitivity tests with the Norwegian Earth System Model

    Directory of Open Access Journals (Sweden)

    P. Räisänen

    2017-12-01

    Full Text Available Snow consists of non-spherical grains of various shapes and sizes. Still, in radiative transfer calculations, snow grains are often treated as spherical. This also applies to the computation of snow albedo in the Snow, Ice, and Aerosol Radiation (SNICAR model and in the Los Alamos sea ice model, version 4 (CICE4, both of which are employed in the Community Earth System Model and in the Norwegian Earth System Model (NorESM. In this study, we evaluate the effect of snow grain shape on climate simulated by NorESM in a slab ocean configuration of the model. An experiment with spherical snow grains (SPH is compared with another (NONSPH in which the snow shortwave single-scattering properties are based on a combination of three non-spherical snow grain shapes optimized using measurements of angular scattering by blowing snow. The key difference between these treatments is that the asymmetry parameter is smaller in the non-spherical case (0.77–0.78 in the visible region than in the spherical case ( ≈  0.89. Therefore, for the same effective snow grain size (or equivalently, the same specific projected area, the snow broadband albedo is higher when assuming non-spherical rather than spherical snow grains, typically by 0.02–0.03. Considering the spherical case as the baseline, this results in an instantaneous negative change in net shortwave radiation with a global-mean top-of-the-model value of ca. −0.22 W m−2. Although this global-mean radiative effect is rather modest, the impacts on the climate simulated by NorESM are substantial. The global annual-mean 2 m air temperature in NONSPH is 1.17 K lower than in SPH, with substantially larger differences at high latitudes. The climatic response is amplified by strong snow and sea ice feedbacks. It is further demonstrated that the effect of snow grain shape could be largely offset by adjusting the snow grain size. When assuming non-spherical snow grains with the parameterized grain

  12. Effects of snow grain shape on climate simulations: sensitivity tests with the Norwegian Earth System Model

    Science.gov (United States)

    Räisänen, Petri; Makkonen, Risto; Kirkevåg, Alf; Debernard, Jens B.

    2017-12-01

    Snow consists of non-spherical grains of various shapes and sizes. Still, in radiative transfer calculations, snow grains are often treated as spherical. This also applies to the computation of snow albedo in the Snow, Ice, and Aerosol Radiation (SNICAR) model and in the Los Alamos sea ice model, version 4 (CICE4), both of which are employed in the Community Earth System Model and in the Norwegian Earth System Model (NorESM). In this study, we evaluate the effect of snow grain shape on climate simulated by NorESM in a slab ocean configuration of the model. An experiment with spherical snow grains (SPH) is compared with another (NONSPH) in which the snow shortwave single-scattering properties are based on a combination of three non-spherical snow grain shapes optimized using measurements of angular scattering by blowing snow. The key difference between these treatments is that the asymmetry parameter is smaller in the non-spherical case (0.77-0.78 in the visible region) than in the spherical case ( ≈ 0.89). Therefore, for the same effective snow grain size (or equivalently, the same specific projected area), the snow broadband albedo is higher when assuming non-spherical rather than spherical snow grains, typically by 0.02-0.03. Considering the spherical case as the baseline, this results in an instantaneous negative change in net shortwave radiation with a global-mean top-of-the-model value of ca. -0.22 W m-2. Although this global-mean radiative effect is rather modest, the impacts on the climate simulated by NorESM are substantial. The global annual-mean 2 m air temperature in NONSPH is 1.17 K lower than in SPH, with substantially larger differences at high latitudes. The climatic response is amplified by strong snow and sea ice feedbacks. It is further demonstrated that the effect of snow grain shape could be largely offset by adjusting the snow grain size. When assuming non-spherical snow grains with the parameterized grain size increased by ca. 70 %, the

  13. Evaluation of Rib Fractures on a Single-in-plane Image Reformation of the Rib Cage in CT Examinations.

    Science.gov (United States)

    Dankerl, Peter; Seuss, Hannes; Ellmann, Stephan; Cavallaro, Alexander; Uder, Michael; Hammon, Matthias

    2017-02-01

    This study aimed to evaluate the diagnostic performance of using a reformatted single-in-plane image reformation of the rib cage for the detection of rib fractures in computed tomography (CT) examinations, employing different levels of radiological experience. We retrospectively evaluated 10 consecutive patients with and 10 patients without rib fractures, whose CT scans were reformatted to a single-in-plane image reformation of the rib cage. Eight readers (two radiologists, two residents in radiology, and four interns) independently evaluated the images for the presence of rib fractures using a reformatted single-in-plane image and a multi-planar image reformation. The time limit was 30 seconds for each read. A consensus of two radiologist readings was considered as the reference standard. Diagnostic performance (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) was assessed and evaluated per rib and per location (anterior, lateral, posterior). To determine the time limit, we prospectively analyzed the average time it took radiologists to assess the rib cage, in a bone window setting, in 50 routine CT examinations. McNemar test was used to compare the diagnostic performances. Single image reformation was successful in all 20 patients. The sensitivity, specificity, PPV, and NPV for the detection of rib fractures using the conventional multi-planar read were 77.5%, 99.2%, 89.9%, and 98.0% for radiologists; 46.3%, 99.7%, 92.5%, and 95.3% for residents; and 29.4%, 99.4%, 82.5%, and 93.9% for interns, respectively. Sensitivity, PPV, and NPV increased across all three groups of experience, using the reformatted single-in-plane image of the rib cage (radiologists: 85.0%, 98.6%, and 98.7%; residents: 80.0%, 92.8%, and 98.2%; interns: 66.9%, 89.9%, and 97.1%), whereas specificity did not change significantly (99.9%, 99.4%, and 99.3%). The diagnostic performance of the interns and residents was significantly better when

  14. SDSS-II: Determination of shape and color parameter coefficients for SALT-II fit model

    Energy Technology Data Exchange (ETDEWEB)

    Dojcsak, L.; Marriner, J.; /Fermilab

    2010-08-01

    In this study we look at the SALT-II model of Type IA supernova analysis, which determines the distance moduli based on the known absolute standard candle magnitude of the Type IA supernovae. We take a look at the determination of the shape and color parameter coefficients, {alpha} and {beta} respectively, in the SALT-II model with the intrinsic error that is determined from the data. Using the SNANA software package provided for the analysis of Type IA supernovae, we use a standard Monte Carlo simulation to generate data with known parameters to use as a tool for analyzing the trends in the model based on certain assumptions about the intrinsic error. In order to find the best standard candle model, we try to minimize the residuals on the Hubble diagram by calculating the correct shape and color parameter coefficients. We can estimate the magnitude of the intrinsic errors required to obtain results with {chi}{sup 2}/degree of freedom = 1. We can use the simulation to estimate the amount of color smearing as indicated by the data for our model. We find that the color smearing model works as a general estimate of the color smearing, and that we are able to use the RMS distribution in the variables as one method of estimating the correct intrinsic errors needed by the data to obtain the correct results for {alpha} and {beta}. We then apply the resultant intrinsic error matrix to the real data and show our results.

  15. 3D phenomenological constitutive modeling of shape memory alloys based on microplane theory

    International Nuclear Information System (INIS)

    Mehrabi, R; Kadkhodaei, M

    2013-01-01

    This paper concerns 3D phenomenological modeling of shape memory alloys using microplane theory. In the proposed approach, transformation is assumed to be the only source of inelastic strain in 1D constitutive laws considered for any generic plane passing through a material point. 3D constitutive equations are derived by generalizing the 1D equations using a homogenization technique. In the developed model, inelastic strain is explicitly stated in terms of the martensite volume fraction. To compare this approach with incremental constitutive models, such an available model is applied in its 1D integral form to the microplane formulation, and it is shown that both the approaches produce similar results for different uniaxial loadings. A nonproportional loading is then studied, and the results are compared with those obtained from an available model in which the inelastic strain is divided into two separate portions for transformation and reorientation. A good agreement is seen between the results of the two approaches, indicating the capability of the proposed microplane formulation in predicting reorientation phenomena in shape memory alloys. The results of the model are compared with available experimental results for a nonproportional loading path, and a good agreement is seen between the findings. (paper)

  16. 3D active shape models of human brain structures: application to patient-specific mesh generation

    Science.gov (United States)

    Ravikumar, Nishant; Castro-Mateos, Isaac; Pozo, Jose M.; Frangi, Alejandro F.; Taylor, Zeike A.

    2015-03-01

    The use of biomechanics-based numerical simulations has attracted growing interest in recent years for computer-aided diagnosis and treatment planning. With this in mind, a method for automatic mesh generation of brain structures of interest, using statistical models of shape (SSM) and appearance (SAM), for personalised computational modelling is presented. SSMs are constructed as point distribution models (PDMs) while SAMs are trained using intensity profiles sampled from a training set of T1-weighted magnetic resonance images. The brain structures of interest are, the cortical surface (cerebrum, cerebellum & brainstem), lateral ventricles and falx-cerebri membrane. Two methods for establishing correspondences across the training set of shapes are investigated and compared (based on SSM quality): the Coherent Point Drift (CPD) point-set registration method and B-spline mesh-to-mesh registration method. The MNI-305 (Montreal Neurological Institute) average brain atlas is used to generate the template mesh, which is deformed and registered to each training case, to establish correspondence over the training set of shapes. 18 healthy patients' T1-weightedMRimages form the training set used to generate the SSM and SAM. Both model-training and model-fitting are performed over multiple brain structures simultaneously. Compactness and generalisation errors of the BSpline-SSM and CPD-SSM are evaluated and used to quantitatively compare the SSMs. Leave-one-out cross validation is used to evaluate SSM quality in terms of these measures. The mesh-based SSM is found to generalise better and is more compact, relative to the CPD-based SSM. Quality of the best-fit model instance from the trained SSMs, to test cases are evaluated using the Hausdorff distance (HD) and mean absolute surface distance (MASD) metrics.

  17. Comparison of Two Methods Used to Model Shape Parameters of Pareto Distributions

    Science.gov (United States)

    Liu, C.; Charpentier, R.R.; Su, J.

    2011-01-01

    Two methods are compared for estimating the shape parameters of Pareto field-size (or pool-size) distributions for petroleum resource assessment. Both methods assume mature exploration in which most of the larger fields have been discovered. Both methods use the sizes of larger discovered fields to estimate the numbers and sizes of smaller fields: (1) the tail-truncated method uses a plot of field size versus size rank, and (2) the log-geometric method uses data binned in field-size classes and the ratios of adjacent bin counts. Simulation experiments were conducted using discovered oil and gas pool-size distributions from four petroleum systems in Alberta, Canada and using Pareto distributions generated by Monte Carlo simulation. The estimates of the shape parameters of the Pareto distributions, calculated by both the tail-truncated and log-geometric methods, generally stabilize where discovered pool numbers are greater than 100. However, with fewer than 100 discoveries, these estimates can vary greatly with each new discovery. The estimated shape parameters of the tail-truncated method are more stable and larger than those of the log-geometric method where the number of discovered pools is more than 100. Both methods, however, tend to underestimate the shape parameter. Monte Carlo simulation was also used to create sequences of discovered pool sizes by sampling from a Pareto distribution with a discovery process model using a defined exploration efficiency (in order to show how biased the sampling was in favor of larger fields being discovered first). A higher (more biased) exploration efficiency gives better estimates of the Pareto shape parameters. ?? 2011 International Association for Mathematical Geosciences.

  18. Current advances in polymer electrolyte fuel cells based on the promotional role of under-rib convection

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K.S. [Industrial Technology Cooperation Center, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Kim, B.G.; Park, K.; Kim, H.M. [Department of Mechanical Engineering and High Safety Vehicle Core Technology Research Center, INJE University, 607 Eobang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of)

    2012-12-15

    Literature data on the promotional role of under-rib convection for polymer electrolyte fuel cells (PEFCs) fueled by hydrogen and methanol are structured and analyzed, thus providing a guide to improving fuel cell performance through the optimization of flow field interaction. Data are presented for both physical and electrochemical performance showing reactant mass transport, electrochemical reaction, water behavior, and power density enhanced by under-rib convection. Performance improvement studies ranging from single cell to stack are presented for measuring the performance of real operating conditions and large-scale setups. The flow field optimization techniques by under-rib convection are derived from the collected data over a wide range of experiments and modeling studies with a variety of components including both single cell and stack arrangements. Numerical models for PEFCs are presented with an emphasis on mass transfer and electrochemical reaction inside the fuel cell. The models are primarily used here as a tool in the parametric analysis of significant design features and to permit the design of the experiment. Enhanced flow field design that utilizes the promotional role of under-rib convection can contribute to commercializing PEFCs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Brain Tumor Segmentation Using a Generative Model with an RBM Prior on Tumor Shape

    DEFF Research Database (Denmark)

    Agn, Mikael; Puonti, Oula; Rosenschöld, Per Munck af

    2016-01-01

    In this paper, we present a fully automated generative method for brain tumor segmentation in multi-modal magnetic resonance images. The method is based on the type of generative model often used for segmenting healthy brain tissues, where tissues are modeled by Gaussian mixture models combined...... the use of the intensity information in the training images. Experiments on public benchmark data of patients suffering from low- and high-grade gliomas show that the method performs well compared to current state-of-the-art methods, while not being tied to any specific imaging protocol....... with a spatial atlas-based tissue prior. We extend this basic model with a tumor prior, which uses convolutional restricted Boltzmann machines (cRBMs) to model the shape of both tumor core and complete tumor, which includes edema and core. The cRBMs are trained on expert segmentations of training images, without...

  20. Modeling Defects, Shape Evolution, and Programmed Auto-origami in Liquid Crystal Elastomers

    Science.gov (United States)

    Konya, Andrew; Gimenez-Pinto, Vianney; Selinger, Robin

    2016-06-01

    Liquid crystal elastomers represent a novel class of programmable shape-transforming materials whose shape change trajectory is encoded in the material’s nematic director field. Using three-dimensional nonlinear finite element elastodynamics simulation, we model a variety of different actuation geometries and device designs: thin films containing topological defects, patterns that induce formation of folds and twists, and a bas-relief structure. The inclusion of finite bending energy in the simulation model reveals features of actuation trajectory that may be absent when bending energy is neglected. We examine geometries with a director pattern uniform through the film thickness encoding multiple regions of positive Gaussian curvature. Simulations indicate that heating such a system uniformly produces a disordered state with curved regions emerging randomly in both directions due to the film’s up/down symmetry. By contrast, applying a thermal gradient by heating the material first on one side breaks up/down symmetry and results in a deterministic trajectory producing a more ordered final shape. We demonstrate that a folding zone design containing cut-out areas accommodates transverse displacements without warping or buckling; and demonstrate that bas-relief and more complex bent/twisted structures can be assembled by combining simple design motifs.

  1. Modeling Defects, Shape Evolution, and Programmed Auto-origami in Liquid Crystal Elastomers

    Directory of Open Access Journals (Sweden)

    Andrew eKonya

    2016-06-01

    Full Text Available Liquid crystal elastomers represent a novel class of programmable shape-transforming materials whose shape change trajectory is encoded in the material’s nematic director field. Using three-dimensional nonlinear finite element elastodynamics simulation, we model a variety of different actuation geometries and device designs: thin films containing topological defects, patterns that induce formation of folds and twists, and a bas-relief structure. The inclusion of finite bending energy in the simulation model reveals features of actuation trajectory that may be absent when bending energy is neglected. We examine geometries with a director pattern uniform through the film thickness encoding multiple regions of positive Gaussian curvature. Simulations indicate that heating such a system uniformly produces a disordered state with curved regions emerging randomly in both directions due to the film’s up/down symmetry. By contrast, applying a thermal gradient by heating the material first on one side breaks up/down symmetry and results in a deterministic trajectory producing a more ordered final shape. We demonstrate that a folding zone design containing cut-out areas accommodates transverse displacements without warping or buckling; and demonstrate that bas-relief and more complex bent/twisted structures can be assembled by combining simple design motifs.

  2. A Constitutive Model for Superelastic Shape Memory Alloys Considering the Influence of Strain Rate

    Directory of Open Access Journals (Sweden)

    Hui Qian

    2013-01-01

    Full Text Available Shape memory alloys (SMAs are a relatively new class of functional materials, exhibiting special thermomechanical behaviors, such as shape memory effect and superelasticity, which enable their applications in seismic engineering as energy dissipation devices. This paper investigates the properties of superelastic NiTi shape memory alloys, emphasizing the influence of strain rate on superelastic behavior under various strain amplitudes by cyclic tensile tests. A novel constitutive equation based on Graesser and Cozzarelli’s model is proposed to describe the strain-rate-dependent hysteretic behavior of superelastic SMAs at different strain levels. A stress variable including the influence of strain rate is introduced into Graesser and Cozzarelli’s model. To verify the effectiveness of the proposed constitutive equation, experiments on superelastic NiTi wires with different strain rates and strain levels are conducted. Numerical simulation results based on the proposed constitutive equation and experimental results are in good agreement. The findings in this paper will assist the future design of superelastic SMA-based energy dissipation devices for seismic protection of structures.

  3. Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape.

    Science.gov (United States)

    Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D; Tardif, Jacques C; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

    2015-01-01

    Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems.

  4. Effect of Particle Shape on Mechanical Behaviors of Rocks: A Numerical Study Using Clumped Particle Model

    Science.gov (United States)

    Rong, Guan; Liu, Guang; Zhou, Chuang-bing

    2013-01-01

    Since rocks are aggregates of mineral particles, the effect of mineral microstructure on macroscopic mechanical behaviors of rocks is inneglectable. Rock samples of four different particle shapes are established in this study based on clumped particle model, and a sphericity index is used to quantify particle shape. Model parameters for simulation in PFC are obtained by triaxial compression test of quartz sandstone, and simulation of triaxial compression test is then conducted on four rock samples with different particle shapes. It is seen from the results that stress thresholds of rock samples such as crack initiation stress, crack damage stress, and peak stress decrease with the increasing of the sphericity index. The increase of sphericity leads to a drop of elastic modulus and a rise in Poisson ratio, while the decreasing sphericity usually results in the increase of cohesion and internal friction angle. Based on volume change of rock samples during simulation of triaxial compression test, variation of dilation angle with plastic strain is also studied. PMID:23997677

  5. Effect of particle shape on mechanical behaviors of rocks: a numerical study using clumped particle model.

    Science.gov (United States)

    Rong, Guan; Liu, Guang; Hou, Di; Zhou, Chuang-Bing

    2013-01-01

    Since rocks are aggregates of mineral particles, the effect of mineral microstructure on macroscopic mechanical behaviors of rocks is inneglectable. Rock samples of four different particle shapes are established in this study based on clumped particle model, and a sphericity index is used to quantify particle shape. Model parameters for simulation in PFC are obtained by triaxial compression test of quartz sandstone, and simulation of triaxial compression test is then conducted on four rock samples with different particle shapes. It is seen from the results that stress thresholds of rock samples such as crack initiation stress, crack damage stress, and peak stress decrease with the increasing of the sphericity index. The increase of sphericity leads to a drop of elastic modulus and a rise in Poisson ratio, while the decreasing sphericity usually results in the increase of cohesion and internal friction angle. Based on volume change of rock samples during simulation of triaxial compression test, variation of dilation angle with plastic strain is also studied.

  6. Differentiating the Causes of Spontaneous Rib Fracture After Breast Cancer.

    Science.gov (United States)

    Harris, Susan R

    2016-12-01

    Spontaneous rib fracture after treatment for primary breast cancer is not uncommon. Although metastatic disease accounts for about 30% of spontaneous rib fractures and should constitute the first line of diagnostic investigation, other possible contributors include primary osteoporosis or secondary osteoporosis resulting from cancer treatments. Chemotherapy-induced menopause, aromatase inhibitors, radiation therapy, and long-term bisphosphonate use can all contribute to bone fragility, including spontaneous rib fractures in the latter 3. Drawing on recent breast cancer practice guidelines as well as population-based studies of fracture risk for women with a history of breast cancer and systematic reviews, this Perspective will provide an update on recent developments in understanding how to differentiate the possible reasons for non-traumatic rib fracture in women treated for breast cancer. In addition to describing the various possible causes of spontaneous rib fracture, the recommended medical and imaging procedures for differentiating among the potential causes will be presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Flank pseudohernia following posterior rib fracture: a case report.

    Science.gov (United States)

    Butensky, Adam M; Gruss, Leah P; Gleit, Zachary L

    2016-10-01

    A pseudohernia is an abdominal wall bulge that may be mistaken for a hernia but that lacks the disruption of the abdominal wall that characterizes a hernia. Thus, the natural history and treatment of this condition differ from those of a hernia. This is the first report of a pseudohernia due to cough-associated rib fracture. A case of pseudohernia due to fractures of the 10 th and 11 th ribs in a 68-year-old white woman is presented. The patient suffered from a major coughing episode 1 year prior to her presentation, after which she noted a progressively enlarging bulge in her left flank. Computed tomography demonstrated a bulge in the abdominal wall containing bowel and spleen but with all muscle and fascial layers intact; in addition, lateral 10 th rib and posterior 11 th rib fractures were noted. As there was no defect in muscle or fascia, we diagnosed a pseudohernia, likely due to a denervation injury from the fractured ribs. Symptomatic treatment was recommended, including wearing a corset and referral to a pain management clinic. Symptomatic treatment is thought to be the mainstay of therapy for pseudohernias, as surgical intervention is unlikely to be of benefit.

  8. [Rib cage ostheosynthesis. Literature review and case reports].

    Science.gov (United States)

    Jiménez-Quijano, Andrés; Varón-Cotés, Juan Carlos; García-Herreros-Hellal, Luis Gerardo; Espinosa-Moya, Beatriz; Rivero-Rapalino, Oscar; Salazar-Marulanda, Michelle

    2015-01-01

    Fractures of the chest wall include sternum and rib fractures. Traditionally they are managed conservatively due to the anatomy of the rib cage that allows most of them to remain stable and to form a callus that unites the fractured segments. In spite of this management, some patients present with chronic pain or instability of the wall which makes them require some type of fixation. The present article performs a literature review based on 4 cases. The first case was a 61 year-old man with blunt chest trauma, with a great deformity of the chest wall associated with subcutaneous emphysema, and pneumothorax. The second case was a 51 year-old man with blunt chest trauma, initially managed at another institution, who despite treatment, had persistent pain and dyspnoea. The third case was a 30 year-old man that suffered a motor vehicle accident, with resulting pain and crepitation of the rib cage and with diagnostic images showing multiple rib fractures. The last case is a 62 year-old man that fell down the stairs, with blunt chest trauma with high intensity pain, dyspnoea and basal ipsilateral hypoventilation. Rib fracture fixation offers a good alternative in selected patients to decrease associated morbidity, leading to a patient's fast return to his or her working life. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  9. Thoracic epidural steroid injection for rib fracture pain.

    Science.gov (United States)

    Rauchwerger, Jacob J; Candido, Kenneth D; Deer, Timothy R; Frogel, Jonathan K; Iadevaio, Robert; Kirschen, Neil B

    2013-06-01

    Treatment for rib fracture pain can be broadly divided into pharmacologic approaches with oral and/or parenteral medication and interventional approaches utilizing neuraxial analgesia or peripheral nerve blocks to provide pain relief. Both approaches attempt to control nociceptive and neuropathic pain secondary to osseous injury and nerve insult, respectively. Success of treatment is ultimately measured by the ability of the selected modality to decrease pain, chest splinting, and to prevent sequelae of injury, such as pneumonia. Typically, opioids and NSAIDs are the drugs of first choice for acute pain because of ease of administration, immediate onset of action, and rapid titration to effect. In contrast, neuropathic pain medications have a slower onset of action and are more difficult to titrate to therapeutic effect. Interventional approaches include interpleural catheters, intercostal nerve blocks, paravertebral nerve blocks, and thoracic and lumbar epidural catheters. Each intervention has its own inherent advantages, disadvantages, and success rates. Rib fracture pain management practice is founded on the thoracic surgical and anesthesiology literature. Articles addressing rib fracture pain are relatively scarce in the pain medicine literature. As life expectancy increases, and as healthcare system modifications are implemented, pain medicine physicians may be consulted to treat increasing number of patients suffering rib fracture pain and may need to resort to novel therapeutic measures because of financial constraints imposed by those changes. Here we present the first published case series of thoracic epidural steroid injections used for management of rib fracture pain. © 2012 The Authors Pain Practice © 2012 World Institute of Pain.

  10. Emerging from the rib: resolving the turtle controversies.

    Science.gov (United States)

    Rice, Ritva; Riccio, Paul; Gilbert, Scott F; Cebra-Thomas, Judith

    2015-05-01

    Two of the major controversies in the present study of turtle shell development involve the mechanism by which the carapacial ridge initiates shell formation and the mechanism by which each rib forms the costal bones adjacent to it. This paper claims that both sides of each debate might be correct-but within the species examined. Mechanism is more properly "mechanisms," and there is more than one single way to initiate carapace formation and to form the costal bones. In the initiation of the shell, the rib precursors may be kept dorsal by either "axial displacement" (in the hard-shell turtles) or "axial arrest" (in the soft-shell turtle Pelodiscus), or by a combination of these. The former process would deflect the rib into the dorsal dermis and allow it to continue its growth there, while the latter process would truncate rib growth. In both instances, though, the result is to keep the ribs from extending into the ventral body wall. Our recent work has shown that the properties of the carapacial ridge, a key evolutionary innovation of turtles, differ greatly between these two groups. Similarly, the mechanism of costal bone formation may differ between soft-shell and hard-shell turtles, in that the hard-shell species may have both periosteal flattening as well as dermal bone induction, while the soft-shelled turtles may have only the first of these processes. © 2015 Wiley Periodicals, Inc.

  11. Improved Frequency Fluctuation Model for Spectral Line Shape Calculations in Fusion Plasmas

    International Nuclear Information System (INIS)

    Ferri, S.; Calisti, A.; Mosse, C.; Talin, B.; Lisitsa, V.

    2010-01-01

    A very fast method to calculate spectral line shapes emitted by plasmas accounting for charge particle dynamics and effects of an external magnetic field is proposed. This method relies on a new formulation of the Frequency Fluctuation Model (FFM), which yields to an expression of the dynamic line profile as a functional of the static distribution function of frequencies. This highly efficient formalism, not limited to hydrogen-like systems, allows to calculate pure Stark and Stark-Zeeman line shapes for a wide range of density, temperature and magnetic field values, which is of importance in plasma physics and astrophysics. Various applications of this method are presented for conditions related to fusion plasmas.

  12. Modeling fiber motion in a pulp pressure screen: the effect of slot shape

    International Nuclear Information System (INIS)

    Dong, S.; Salcudean, M.; Gartshore, I.

    2003-01-01

    A pressure screen is a piece of equipment in the pulp and paper industry used either to remove contaminants from the pulp suspension or to separate fibers having different properties. Contaminants such as fiber bundles, bark and plastic specks are introduced when fibers are separated from the wood by mechanical or chemical pulping processes. Contaminants significantly affect the strength and smoothness of the paper and must be removed before the final paper is produced. The screen plate is a critical part of the pressure screen and its design is the key to screen performance. This paper uses a new and comprehensive CFD simulation tool to examine the flow and fiber behavior in a single slot screen having any reasonable slot shape. -This simulation tool includes three coupled models: first, the flow model solves the Reynolds Averaged Navier-Stokes (RANS) equation using the standard k - ε turbulence model to predict the flow field in the equipment. Second, a three-dimensional flexible fiber model is used to track the fiber trajectory in the screen. Third, a very general wall model is used to deal with the case when a fiber touches the equipment wall. The simulated results show that the slot shape has a critical influence on fiber behavior and screen performance. Three general slot shapes were investigated: the smooth slot, the step-step contour slot and slope-slope contour slot. Of these the slope-slope contour slot provides the best passage for the fibers with a length of 1mm and 3mm. (author)

  13. Finite element modeling of the human kidney for probabilistic occupant models: Statistical shape analysis and mesh morphing.

    Science.gov (United States)

    Yates, Keegan M; Untaroiu, Costin D

    2018-04-16

    Statistical shape analysis was conducted on 15 pairs (left and right) of human kidneys. It was shown that the left and right kidney were significantly different in size and shape. In addition, several common modes of kidney variation were identified using statistical shape analysis. Semi-automatic mesh morphing techniques have been developed to efficiently create subject specific meshes from a template mesh with a similar geometry. Subject specific meshes as well as probabilistic kidney meshes were created from a template mesh. Mesh quality remained about the same as the template mesh while only taking a fraction of the time to create the mesh from scratch or morph with manually identified landmarks. This technique can help enhance the quality of information gathered from experimental testing with subject specific meshes as well as help to more efficiently predict injury by creating models with the mean shape as well as models at the extremes for each principal component. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    Science.gov (United States)

    Hartl, D. J.; Lagoudas, D. C.

    2009-10-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation.

  15. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    International Nuclear Information System (INIS)

    Hartl, D J; Lagoudas, D C

    2009-01-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation

  16. Mechanisms Of Saucer-Shaped Sill Emplacement: Insight From Experimental Modeling

    Science.gov (United States)

    Galland, O.; Planke, S.; Malthe-Sørenssen, A.; Polteau, S.; Svensen, H.; Podladchikov, Y. Y.

    2006-12-01

    It has been recently demonstrated that magma intrusions in sedimentary basins had a strong impact on petroleum systems. Most of these intrusions are sills, and especially saucer-shaped sills. These features can be observed in many sedimentary basins (i.e. the Karoo basin, South Africa; the Norwegian and North Sea; the Tunguska basin, Siberia; the Neuquén basin in Argentina). The occurrence of such features in so various settings suggests that their emplacement results from fundamental processes. However, the mechanisms that govern their formation remain poorly constrained. Experiments were conducted to simulate the emplacement of saucer-shaped magma intrusions in sedimentary basins. The model rock and magma were fine-grained silica flour and molten vegetable oil, respectively. This modeling technique allows simultaneous simulation of magma emplacement and brittle deformation at a basin scale. For our purpose, we performed our experiments without external deformation. During the experiments, the oil was injected horizontally at constant flow rate within the silica flour. Then the oil initially emplaced in a sill, whereas the surface of the model inflated into a smooth dome. Subsequently, the oil propagated upwards along inclined sheets, finally reaching the surface at the edge of the dome. The resulting geometries of the intrusions were saucer-shaped sills. Then the oil solidified, and the model was cut in serial cross-sections through which the structures of the intrusive body and of the overburden can be observed. In order to constraint the processes governing the emplacement of such features, we performed a parametric study based on a set of experiments in which we systematically varied parameters such as the depth of emplacement and the injection flow rate of the oil. Our results showed that saucer diameters are larger at deeper level of emplacement. Opposite trend was obtained with varying injection flow rates. Based on our results, we conducted a detailed

  17. An analytical model accounting for tip shape evolution during atom probe analysis of heterogeneous materials.

    Science.gov (United States)

    Rolland, N; Larson, D J; Geiser, B P; Duguay, S; Vurpillot, F; Blavette, D

    2015-12-01

    An analytical model describing the field evaporation dynamics of a tip made of a thin layer deposited on a substrate is presented in this paper. The difference in evaporation field between the materials is taken into account in this approach in which the tip shape is modeled at a mesoscopic scale. It was found that the non-existence of sharp edge on the surface is a sufficient condition to derive the morphological evolution during successive evaporation of the layers. This modeling gives an instantaneous and smooth analytical representation of the surface that shows good agreement with finite difference simulations results, and a specific regime of evaporation was highlighted when the substrate is a low evaporation field phase. In addition, the model makes it possible to calculate theoretically the tip analyzed volume, potentially opening up new horizons for atom probe tomographic reconstruction. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. A mathematical model for smart functionally graded beam integrated with shape memory alloy actuators

    International Nuclear Information System (INIS)

    Sepiani, H.; Ebrahimi, F.; Karimipour, H.

    2009-01-01

    This paper presents a theoretical study of the thermally driven behavior of a shape memory alloy (SMA)/FGM actuator under arbitrary loading and boundary conditions by developing an integrated mathematical model. The model studied is established on the geometric parameters of the three-dimensional laminated composite box beam as an actuator that consists of a functionally graded core integrated with SMA actuator layers with a uniform rectangular cross section. The constitutive equation and linear phase transformation kinetics relations of SMA layers based on Tanaka and Nagaki model are coupled with the governing equation of the actuator to predict the stress history and to model the thermo-mechanical behavior of the smart shape memory alloy/FGM beam. Based on the classical laminated beam theory, the explicit solution to the structural response of the structure, including axial and lateral deflections of the structure, is investigated. As an example, a cantilever box beam subjected to a transverse concentrated load is solved numerically. It is found that the changes in the actuator's responses during the phase transformation due to the strain recovery are significant

  19. A multidimensional stability model for predicting shallow landslide size and shape across landscapes.

    Science.gov (United States)

    Milledge, David G; Bellugi, Dino; McKean, Jim A; Densmore, Alexander L; Dietrich, William E

    2014-11-01

    The size of a shallow landslide is a fundamental control on both its hazard and geomorphic importance. Existing models are either unable to predict landslide size or are computationally intensive such that they cannot practically be applied across landscapes. We derive a model appropriate for natural slopes that is capable of predicting shallow landslide size but simple enough to be applied over entire watersheds. It accounts for lateral resistance by representing the forces acting on each margin of potential landslides using earth pressure theory and by representing root reinforcement as an exponential function of soil depth. We test our model's ability to predict failure of an observed landslide where the relevant parameters are well constrained by field data. The model predicts failure for the observed scar geometry and finds that larger or smaller conformal shapes are more stable. Numerical experiments demonstrate that friction on the boundaries of a potential landslide increases considerably the magnitude of lateral reinforcement, relative to that due to root cohesion alone. We find that there is a critical depth in both cohesive and cohesionless soils, resulting in a minimum size for failure, which is consistent with observed size-frequency distributions. Furthermore, the differential resistance on the boundaries of a potential landslide is responsible for a critical landslide shape which is longer than it is wide, consistent with observed aspect ratios. Finally, our results show that minimum size increases as approximately the square of failure surface depth, consistent with observed landslide depth-area data.

  20. Epidural analgesia in patients with traumatic rib fractures

    DEFF Research Database (Denmark)

    Duch, P; Møller, M H

    2015-01-01

    BACKGROUND: Traumatic rib fractures are a common condition associated with considerable morbidity and mortality. Observational studies have suggested improved outcome in patients receiving continuous epidural analgesia (CEA). The aim of the present systematic review of randomised controlled trials...... (RCTs) was to assess the benefit and harm of CEA compared with other analgesic interventions in patients with traumatic rib fractures. METHODS: We performed a systematic review with meta-analysis and trial sequential analysis (TSA). Eligible trials were RCTs comparing CEA with other analgesic...... interventions in patients with traumatic rib fractures. Cumulative relative risks (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were estimated, and risk of systematic and random errors was assessed. The predefined primary outcome measures were mortality, pneumonia and duration...

  1. VOF Modeling and Analysis of the Segmented Flow in Y-Shaped Microchannels for Microreactor Systems

    Directory of Open Access Journals (Sweden)

    Xian Wang

    2013-01-01

    Full Text Available Microscaled devices receive great attention in microreactor systems for producing high renewable energy due to higher surface-to-volume, higher transport rates (heat or/and mass transfer rates, and other advantages over conventional-size reactors. In this paper, the two-phase liquid-liquid flow in a microchannel with various Y-shaped junctions has been studied numerically. Two kinds of immiscible liquids were injected into a microchannel from the Y-shaped junctions to generate the segment flow mode. The segment length was studied. The volume of fluid (VOF method was used to track the liquid-liquid interface and the piecewise-liner interface construction (PLIC technique was adopted to get a sharp interface. The interfacial tension was simulated with continuum surface force (CSF model and the wall adhesion boundary condition was taken into consideration. The simulated flow pattern presents consistence with our experimental one. The numerical results show that a segmented flow mode appears in the main channel. Under the same inlet velocities of two liquids, the segment lengths of the two liquids are the same and depend on the inclined angles of two lateral channels. The effect of inlet velocity is studied in a typical T-shaped microchannel. It is found that the ratio between the lengths of two liquids is almost equal to the ratio between their inlet velocities.

  2. Modeling the preferred shapes of polyamine transporter ligands and dihydromotuporamine-C mimics: shovel versus hoe.

    Science.gov (United States)

    Breitbeil, Fred; Kaur, Navneet; Delcros, Jean-Guy; Martin, Bénédicte; Abboud, Khalil A; Phanstiel, Otto

    2006-04-20

    Preferred conformers generated from motuporamine and anthracene-polyamine derivatives provided insight into the shapes associated with polyamine transporter (PAT) recognition and potentially dihydromotuporamine C (4a) bioactivity. Molecular modeling revealed that N(1)-(anthracen-9-ylmethyl)-3,3-triamine (6a), N(1)-(anthracen-9-ylmethyl)-4,4-triamine (6b), N(1)-(anthracen-9-ylmethyl)-N(1)-ethyl-3,3-triamine (7a), N(1)-(anthracen-9-ylmethyl)-N(1)-ethyl-4,4-triamine (7b), and 4a all preferred a hoe motif. This hoe shape was defined by the all-anti polyamine shaft extending above the relatively flat, appended ring system. The hoe geometry was also inferred by the (1)H NMR spectrum of the free amine of 7a (CDCl(3)), which showed a strong shielding effect of the anthracene ring on the chemical shifts associated with the appended polyamine chain. This shielding effect was found to be independent over a broad concentration range of 7a, which also supported an intramolecular phenomenon. The degree of substitution at the N(1)-position seems to be an important determinant of both the molecular shape preferences and biological activity of anthracenylmethyl-polyamine conjugates.

  3. COMPARING 3D FOOT SHAPE MODELS BETWEEN TAIWANESE AND JAPANESE FEMALES.

    Science.gov (United States)

    Lee, Yu-Chi; Kouchi, Makiko; Mochimaru, Masaaki; Wang, Mao-Jiun

    2015-06-01

    This study compares foot shape and foot dimensions between Taiwanese and Japanese females. One hundred Taiwanese and 100 Japanese female 3D foot scanning data were used for comparison. To avoid the allometry effect, data from 23 Taiwanese and 19 Japanese with foot length between 233 to 237 mm were used for shape comparison. Homologous models created for the right feet of the 42 subjects were analyzed by Multidimensional Scaling. The results showed that there were significant differences in the forefoot shape between the two groups, and Taiwanese females had slightly wider feet with straighter big toe than Japanese females. The results of body and foot dimension comparison indicated that Taiwanese females were taller, heavier and had larger feet than Japanese females, while Japanese females had significantly larger toe 1 angle. Since some Taiwanese shoemakers adopt the Japanese shoe sizing system for making shoes, appropriateness of the shoe sizing system was also discussed. The present results provide very useful information for improving shoe last design and footwear fit for Taiwanese females.

  4. The Effect of Sterilization on Size and Shape of Fat Globules in Model Processed Cheese Samples

    Directory of Open Access Journals (Sweden)

    B. Tremlová

    2006-01-01

    Full Text Available Model cheese samples from 4 independent productions were heat sterilized (117 °C, 20 minutes after the melting process and packing with an aim to prolong their durability. The objective of the study was to assess changes in the size and shape of fat globules due to heat sterilization by using image analysis methods. The study included a selection of suitable methods of preparation mounts, taking microphotographs and making overlays for automatic processing of photographs by image analyser, ascertaining parameters to determine the size and shape of fat globules and statistical analysis of results obtained. The results of the experiment suggest that changes in shape of fat globules due to heat sterilization are not unequivocal. We found that the size of fat globules was significantly increased (p < 0.01 due to heat sterilization (117 °C, 20 min, and the shares of small fat globules (up to 500 μm2, or 100 μm2 in the samples of heat sterilized processed cheese were decreased. The results imply that the image analysis method is very useful when assessing the effect of technological process on the quality of processed cheese quality.

  5. Shape coexistence in 16O, 72Se, and 240Pu: a comprehensive view based on the dynamic deformation model

    International Nuclear Information System (INIS)

    Kumar, K.

    1980-01-01

    The dynamic deformation model has been improved and applied to calculate the potential energies of deformation and the collective spectra of 16 O, 72 Se, and 240 Pu. A comprehensive view based on the dynamics of five-dimensional quadrupole motion is provided for three seemingly different types of shape coexistence: spherical (Op - Oh) and deformed (2p - 2h) shapes in 16 O, spherical and deformed minima in the potential energy surface of 72 Se, ground-state shape and the fission-isomer shape of 240 Pu. 5 figures, 3 tables

  6. Surgical treatment of rib fracture nonunion: A single center experience.

    Science.gov (United States)

    de Jong, M B; Houwert, R M; van Heerde, S; de Steenwinkel, M; Hietbrink, F; Leenen, L P H

    2018-03-01

    In contrast to the emerging evidence on the operative treatment of flail chest, there is a paucity of literature on the surgical treatment of rib fracture nonunion. The purpose of this study was to describe our standardized approach and report the outcome (e.g. patient satisfaction, pain and complications) after surgical treatment of a rib fracture nonunion. A single centre retrospective cohort study was performed at a level 1 trauma centre. Symptomatic rib nonunion was defined as a severe persistent localized pain associated with the nonunion of one or more rib fractures on a chest CT scan at least 3 months after the initial trauma. Patients after initial operative treatment of rib fractures were excluded. Nineteen patients (11 men, 8 women), with symptomatic nonunions were included. Fourteen patients were referred from other hospitals and 8 patients received treatment from a pain medicine specialist. The mean follow-up was 36 months. No in-hospital complications were observed. In 2 patients, new fractures adjacent to the implant, without new trauma were observed. Furthermore 3 patients requested implant removal with a persistent nonunion in one patient. There was a mean follow-up of 36 months, the majority of patients (n = 13) were satisfied with the results of their surgical treatment and all patients experienced a reduction in the number of complaints. Persisting pain was a common complaint. Three patients reporting severe pain used opioid analgesics on a daily or weekly basis. Only 1 patient needed ongoing treatment by a pain medicine specialist. Surgical fixation of symptomatic rib nonunion is a safe and feasible procedure, with a low perioperative complication rate, and might be beneficial in selected symptomatic patients in the future. In our study, although the majority of patients were satisfied and the pain level subjectively decreases, complaints of persistent pain were common. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Comparison of Different Turbulence Models for Numerical Simulation of Pressure Distribution in V-Shaped Stepped Spillway

    Directory of Open Access Journals (Sweden)

    Zhaoliang Bai

    2017-01-01

    Full Text Available V-shaped stepped spillway is a new shaped stepped spillway, and the pressure distribution is quite different from that of the traditional stepped spillway. In this paper, five turbulence models were used to simulate the pressure distribution in the skimming flow regimes. Through comparing with the physical value, the realizable k-ε model had better precision in simulating the pressure distribution. Then, the flow pattern of V-shaped and traditional stepped spillways was given to illustrate the unique pressure distribution using realizable k-ε turbulence model.

  8. SU-E-I-58: Objective Models of Breast Shape Undergoing Mammography and Tomosynthesis Using Principal Component Analysis.

    Science.gov (United States)

    Feng, Ssj; Sechopoulos, I

    2012-06-01

    To develop an objective model of the shape of the compressed breast undergoing mammographic or tomosynthesis acquisition. Automated thresholding and edge detection was performed on 984 anonymized digital mammograms (492 craniocaudal (CC) view mammograms and 492 medial lateral oblique (MLO) view mammograms), to extract the edge of each breast. Principal Component Analysis (PCA) was performed on these edge vectors to identify a limited set of parameters and eigenvectors that. These parameters and eigenvectors comprise a model that can be used to describe the breast shapes present in acquired mammograms and to generate realistic models of breasts undergoing acquisition. Sample breast shapes were then generated from this model and evaluated. The mammograms in the database were previously acquired for a separate study and authorized for use in further research. The PCA successfully identified two principal components and their corresponding eigenvectors, forming the basis for the breast shape model. The simulated breast shapes generated from the model are reasonable approximations of clinically acquired mammograms. Using PCA, we have obtained models of the compressed breast undergoing mammographic or tomosynthesis acquisition based on objective analysis of a large image database. Up to now, the breast in the CC view has been approximated as a semi-circular tube, while there has been no objectively-obtained model for the MLO view breast shape. Such models can be used for various breast imaging research applications, such as x-ray scatter estimation and correction, dosimetry estimates, and computer-aided detection and diagnosis. © 2012 American Association of Physicists in Medicine.

  9. Shape model of the maxillary dental arch using Fourier descriptors with an application in the rehabilitation for edentulous patient.

    Science.gov (United States)

    Rijal, Omar M; Abdullah, Norli A; Isa, Zakiah M; Noor, Norliza M; Tawfiq, Omar F

    2013-01-01

    The knowledge of teeth positions on the maxillary arch is useful in the rehabilitation of the edentulous patient. A combination of angular (θ), and linear (l) variables representing position of four teeth were initially proposed as the shape descriptor of the maxillary dental arch. Three categories of shape were established, each having a multivariate normal distribution. It may be argued that 4 selected teeth on the standardized digital images of the dental casts could be considered as insufficient with respect to representing shape. However, increasing the number of points would create problems with dimensions and proof of existence of the multivariate normal distribution is extremely difficult. This study investigates the ability of Fourier descriptors (FD) using all maxillary teeth to find alternative shape models. Eight FD terms were sufficient to represent 21 points on the arch. Using these 8 FD terms as an alternative shape descriptor, three categories of shape were verified, each category having the complex normal distribution.

  10. Burned-out seminoma revealed by solitary rib bone metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Nishisho, Toshihiko; Miyagi, Ryo; Sairyo, Koichi [Tokushima University Graduate School, Department of Orthopedics, Institute of Biomedical Sciences, Tokushima-city, Tokushima (Japan); Sakaki, Mika [Saitama Medical University International Medical Center, Department of Pathology, Hidaka-city, Saitama (Japan); Takao, Shoichiro [Tokushima University Graduate School, Department of Radiology, Institute of Biomedical Sciences, Tokushima-city, Tokushima (Japan)

    2017-10-15

    Burned-out tumor is a rare phenomenon in which a testicular tumor regresses in the primary lesion and progresses in a metastatic lesion. We report the case of a 30-year-old male with burned-out seminoma revealed by open biopsy of solitary 10th rib bone metastasis. He underwent inguinal orchiectomy, which revealed hyalinization, indicating a spontaneously regressed testicular tumor. Chemotherapy for seminoma was administered in three cycles of bleomycin + etoposide + cisplatin therapy. The chemotherapy was effective, and wide resection of the rib was subsequently performed. No postoperative chemotherapy was performed, and there has been no evidence of recurrence for 3 years postoperatively. (orig.)

  11. Sternoplasty and rib distraction in neonatal Jeune syndrome.

    LENUS (Irish Health Repository)

    Conroy, Eimear

    2010-09-01

    A 12-week-old boy with Jeune syndrome (asphyxiating thoracic dystrophy) was referred to the orthopaedic unit with progressive respiratory failure, recurrent respiratory tract infections, and recurrent admissions to the intensive care unit for ventilatory support. His chest x-ray revealed a small and narrow thoracic cage with short broad ribs and abnormal costal cartilages. His chest expansion was impaired by the short, horizontally positioned ribs resulting in alveolar hypoventilation. Without surgical intervention to expand his thoracic cage, he would die of respiratory failure.

  12. Statistical modelling of the interplay between solute shape and rejection in porous membranes

    DEFF Research Database (Denmark)

    Vinther, Frank; Pinelo, Manuel; Brøns, Morten

    2012-01-01

    ellipsoid was approximately equal to the radius of the pores, in case the spherical size of the particle was smaller than the membrane pore. Furthermore, for spherical particles larger than the pore, such a maximum was found to occur after the smaller of the radii was smaller than the pore radius. Either...... for spherical particles bigger or smaller than the pore radius, K was monotonically decreasing towards zero as the particles became more elongated. When relating the values of K to the friction model, the maximal rejection coefficient was found to reach a characteristic minimum when changing shape. The results...

  13. Kernel Principal Component Analysis and its Applications in Face Recognition and Active Shape Models

    OpenAIRE

    Wang, Quan

    2012-01-01

    Principal component analysis (PCA) is a popular tool for linear dimensionality reduction and feature extraction. Kernel PCA is the nonlinear form of PCA, which better exploits the complicated spatial structure of high-dimensional features. In this paper, we first review the basic ideas of PCA and kernel PCA. Then we focus on the reconstruction of pre-images for kernel PCA. We also give an introduction on how PCA is used in active shape models (ASMs), and discuss how kernel PCA can be applied ...

  14. Increasing dimension of structures by 4D printing shape memory polymers via fused deposition modeling

    Science.gov (United States)

    Hu, G. F.; Damanpack, A. R.; Bodaghi, M.; Liao, W. H.

    2017-12-01

    The main objective of this paper is to introduce a 4D printing method to program shape memory polymers (SMPs) during fabrication process. Fused deposition modeling (FDM) as a filament-based printing method is employed to program SMPs during depositing the material. This method is implemented to fabricate complicated polymeric structures by self-bending features without need of any post-programming. Experiments are conducted to demonstrate feasibility of one-dimensional (1D)-to 2D and 2D-to-3D self-bending. It is shown that 3D printed plate structures can transform into masonry-inspired 3D curved shell structures by simply heating. Good reliability of SMP programming during printing process is also demonstrated. A 3D macroscopic constitutive model is established to simulate thermo-mechanical features of the printed SMPs. Governing equations are also derived to simulate programming mechanism during printing process and shape change of self-bending structures. In this respect, a finite element formulation is developed considering von-Kármán geometric nonlinearity and solved by implementing iterative Newton-Raphson scheme. The accuracy of the computational approach is checked with experimental results. It is demonstrated that the theoretical model is able to replicate the main characteristics observed in the experiments. This research is likely to advance the state of the art FDM 4D printing, and provide pertinent results and computational tool that are instrumental in design of smart materials and structures with self-bending features.

  15. Time series modeling of live-cell shape dynamics for image-based phenotypic profiling.

    Science.gov (United States)

    Gordonov, Simon; Hwang, Mun Kyung; Wells, Alan; Gertler, Frank B; Lauffenburger, Douglas A; Bathe, Mark

    2016-01-01

    Live-cell imaging can be used to capture spatio-temporal aspects of cellular responses that are not accessible to fixed-cell imaging. As the use of live-cell imaging continues to increase, new computational procedures are needed to characterize and classify the temporal dynamics of individual cells. For this purpose, here we present the general experimental-computational framework SAPHIRE (Stochastic Annotation of Phenotypic Individual-cell Responses) to characterize phenotypic cellular responses from time series imaging datasets. Hidden Markov modeling is used to infer and annotate morphological state and state-switching properties from image-derived cell shape measurements. Time series modeling is performed on each cell individually, making the approach broadly useful for analyzing asynchronous cell populations. Two-color fluorescent cells simultaneously expressing actin and nuclear reporters enabled us to profile temporal changes in cell shape following pharmacological inhibition of cytoskeleton-regulatory signaling pathways. Results are compared with existing approaches conventionally applied to fixed-cell imaging datasets, and indicate that time series modeling captures heterogeneous dynamic cellular responses that can improve drug classification and offer additional important insight into mechanisms of drug action. The software is available at http://saphire-hcs.org.

  16. Explicit Nonlinear Model Predictive Control for a Saucer-Shaped Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Zhihui Xing

    2013-01-01

    Full Text Available A lifting body unmanned aerial vehicle (UAV generates lift by its body and shows many significant advantages due to the particular shape, such as huge loading space, small wetted area, high-strength fuselage structure, and large lifting area. However, designing the control law for a lifting body UAV is quite challenging because it has strong nonlinearity and coupling, and usually lacks it rudders. In this paper, an explicit nonlinear model predictive control (ENMPC strategy is employed to design a control law for a saucer-shaped UAV which can be adequately modeled with a rigid 6-degrees-of-freedom (DOF representation. In the ENMPC, control signal is calculated by approximation of the tracking error in the receding horizon by its Taylor-series expansion to any specified order. It enhances the advantages of the nonlinear model predictive control and eliminates the time-consuming online optimization. The simulation results show that ENMPC is a propriety strategy for controlling lifting body UAVs and can compensate the insufficient control surface area.

  17. Thermodynamic constitutive model for load-biased thermal cycling test of shape memory alloy

    International Nuclear Information System (INIS)

    Young, Sung; Nam, Tae-Hyun

    2013-01-01

    Graphical abstract: - Highlights: • Thermodynamic calculation model for martensitic transformation of shape memory alloy was proposed. • Evolution of the self-accommodation was considered independently by a rate-dependent kinetic equation. • Finite element calculation was conducted for B2–B19′ transformation of Ti–44.5Ni–5Cu–0.5 V (at.%). • Three-dimensional numerical results predict the macroscopic strain under bias loading accurately. - Abstract: This paper presents a three-dimensional calculation model for martensitic phase transformation of shape memory alloy. Constitutive model based on thermodynamic theory was provided. The average behavior was accounted for by considering the volume fraction of each martensitic variant in the material. Evolution of the volume fraction of each variant was determined by a rate-dependent kinetic equation. We assumed that nucleation rate is faster for the self-accommodation than for the stress-induced variants. Three-dimensional finite element analysis was conducted and the results were compared with the experimental data of Ti–44.5Ni–5Cu–0.5 V (at.%) alloy under bias loading

  18. Acute rib fracture diagnosis in an infant by US: a matter of child protection

    International Nuclear Information System (INIS)

    Kelloff, Jennifer; Spivey, Maria; Hulett, Rebecca

    2009-01-01

    Rib fractures in infants and children are highly specific for inflicted injury in the absence of a major accidental injury or underlying bone disorder. We present a 9-week-old infant diagnosed with an acute rib fracture by US at the site where physicians palpated chest wall crepitus when no rib fractures had been visualized on the skeletal survey, including oblique views of the ribs. Based on the US diagnosis of the acute rib fracture the infant was taken into protective custody. Follow-up skeletal survey 2 weeks later revealed healing fractures of the left 6th and 7th posterolateral ribs and right 7th, 8th and 9th anterolateral ribs. We were unable to locate previous reports describing the diagnosis of rib fractures in infants by US. (orig.)

  19. Acute rib fracture diagnosis in an infant by US: a matter of child protection

    Energy Technology Data Exchange (ETDEWEB)

    Kelloff, Jennifer; Spivey, Maria [Washington University School of Medicine, Department of Pediatrics, Section on Child Abuse and Neglect, St. Louis Children' s Hospital, One Children' s Place, Box 8116, St. Louis, MO (United States); Hulett, Rebecca [Washington University School of Medicine, Department of Radiology, St. Louis Children' s Hospital, St. Louis, MO (United States)

    2009-01-15

    Rib fractures in infants and children are highly specific for inflicted injury in the absence of a major accidental injury or underlying bone disorder. We present a 9-week-old infant diagnosed with an acute rib fracture by US at the site where physicians palpated chest wall crepitus when no rib fractures had been visualized on the skeletal survey, including oblique views of the ribs. Based on the US diagnosis of the acute rib fracture the infant was taken into protective custody. Follow-up skeletal survey 2 weeks later revealed healing fractures of the left 6th and 7th posterolateral ribs and right 7th, 8th and 9th anterolateral ribs. We were unable to locate previous reports describing the diagnosis of rib fractures in infants by US. (orig.)

  20. Modeling and Bayesian parameter estimation for shape memory alloy bending actuators

    Science.gov (United States)

    Crews, John H.; Smith, Ralph C.

    2012-04-01

    In this paper, we employ a homogenized energy model (HEM) for shape memory alloy (SMA) bending actuators. Additionally, we utilize a Bayesian method for quantifying parameter uncertainty. The system consists of a SMA wire attached to a flexible beam. As the actuator is heated, the beam bends, providing endoscopic motion. The model parameters are fit to experimental data using an ordinary least-squares approach. The uncertainty in the fit model parameters is then quantified using Markov Chain Monte Carlo (MCMC) methods. The MCMC algorithm provides bounds on the parameters, which will ultimately be used in robust control algorithms. One purpose of the paper is to test the feasibility of the Random Walk Metropolis algorithm, the MCMC method used here.