bluuebunny/crossref_metadata_2025 huggingface dataset:
TRPV1: A Potential Drug Target for Treating Various Diseases
Authors: Brito Rafael , Sheth Sandeep , Mukherjea Debashree , Rybak Leonard , Ramkumar Vickram
Published: May 2014

Transient receptor potential vanilloid 1 (TRPV1) is an ion channel present on sensory neurons which is activated by heat, protons, capsaicin and a variety of endogenous lipids termed endovanilloids. As such, TRPV1 serves as a multimodal sensor of noxious stimuli which could trigger counteractive measures to avoid pain and injury. Activation of TRPV1 has been linked to chronic inflammatory pain conditions and peripheral neuropathy, as observed in diabetes. Expression of TRPV1 is also observed in non-neuronal sites such as the epithelium of bladder and lungs and in hair cells of the cochlea. At these sites, activation of TRPV1 has been implicated in the pathophysiology of diseases such as cystitis, asthma and hearing loss. Therefore, drugs which could modulate TRPV1 channel activity could be useful for the treatment of conditions ranging from chronic pain to hearing loss. This review describes the roles of TRPV1 in the normal physiology and pathophysiology of selected organs of the body and highlights how drugs targeting this channel could be important clinically.
A Probabilistic Description of the Configurational Entropy of Mixing
Authors: Garcés Jorge
Published: May 2014

This work presents a formalism to calculate the configurational entropy of mixing based on the identification of non-interacting atomic complexes in the mixture and the calculation of their respective probabilities, instead of computing the number of atomic configurations in a lattice. The methodology is applied in order to develop a general analytical expression for the configurational entropy of mixing of interstitial solutions. The expression is valid for any interstitial concentration, is suitable for the treatment of interstitial short-range order (SRO) and can be applied to tetrahedral or octahedral interstitial solutions in any crystal lattice. The effect of the SRO of H on the structural properties of the Nb-H and bcc Zr-H solid solutions is studied using an accurate description of the configurational entropy. The methodology can also be applied to systems with no translational symmetry, such as liquids and amorphous materials. An expression for the configurational entropy of a granular system composed by equal sized hard spheres is deduced.
The Effects of Facilitating Feedback on Online Learners’ Cognitive Engagement: Evidence from the Asynchronous Online Discussion
Authors: Guo Wenge , Chen Ye , Lei Jing , Wen Yan
Published: May 2014

With a large-scale online K-12 teacher professional development course as the research context, this study examined the effects of facilitating feedback on online learners’ cognitive engagement using quasi-experiment method. A total of 1,540 discussion messages from 110 learners (65 in the experimental group and 45 in the control group) were both quantitatively and qualitatively analyzed. Results revealed that facilitating feedback significantly impacted learners’ cognitive engagement: (1) the level of cognitive engagement presented in treatment group was significantly higher than that of control group; (2) cognitive engagement levels of original postings increased overtime in the treatment group, while decreased in the control group; (3) the difference in discussion quantities between two groups was not significant. Effective feedback strategies and the importance of facilitating feedback in creating quality online instruction were discussed.
Using VEGNET In-Situ Monitoring LiDAR (IML) to Capture Dynamics of Plant Area Index, Structure and Phenology in Aspen Parkland Forests in Alberta, Canada
Authors: Portillo-Quintero Carlos , Sanchez-Azofeifa Arturo , Culvenor Darius
Published: May 2014

The use of ceptometers and digital hemispherical photographs to estimate Plant Area Index (PAI) often include biases and errors from instrument positioning, orientation and data analysis. As an alternative to these methods, we used an In-Situ Monitoring LiDAR system that provides indirect measures of PAI and Plant Area Volume Density (PAVD) at a fixed angle, based on optimized principles and algorithms for PAI retrieval. The instrument was installed for 22 nights continuously from September 26 to October 17, 2013 during leaf-fall in an Aspen Parkland Forest. A total of 85 scans were performed (~4 scans per night). PAI measured decreased from 1.27 to 0.67 during leaf-fall, which is consistent with values reported in the literature. PAVD profiles allowed differentiating the contribution of PAI per forest strata. Phenological changes were captured in four ways: number of hits, maximum cumulative and absolute PAI values, time series of PAVD profiles and PAI values per forest strata. We also found that VEGNET IML Canopy PAI and MODIS LAI values showed a similar decreasing trend and differed by 2%–15%. Our results indicate that the VEGNET IML has great potential for rapid forest structural characterization and for ground validation of PAI/LAI at a temporal frequency compatible with earth observation satellites.
3-(4-Amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole
Authors: Pagoria Philip , Zhang Maoxi , Racoveanu Ana , DeHope Alan , Tsyshevsky Roman , Kuklja Maija
Published: May 2014

The title compound 3-(4-amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (ANFF-1) was synthesized by: (1) by reaction of 3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (BNFF-1) with gaseous ammonia in toluene and (2) by partial oxidation of 3,4-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (BAFF-1) with 35% H2O2 in concentrated H2SO4.
Tipping Points in Seaweed Genetic Engineering: Scaling Up Opportunities in the Next Decade
Authors: Lin Hanzhi , Qin Song
Published: May 2014

Seaweed genetic engineering is a transgenic expression system with unique features compared with those of heterotrophic prokaryotes and higher plants. This study discusses several newly sequenced seaweed nuclear genomes and the necessity that research on vector design should consider endogenous promoters, codon optimization, and gene copy number. Seaweed viruses and artificial transposons can be applied as transformation methods after acquiring a comprehensive understanding of the mechanism of viral infections in seaweeds and transposon patterns in seaweed genomes. After cultivating transgenic algal cells and tissues in a photobioreactor, a biosafety assessment of genetically modified (GM) seaweeds must be conducted before open-sea application. We propose a set of programs for the evaluation of gene flow from GM seaweeds to local/geographical environments. The effective implementation of such programs requires fundamentally systematic and interdisciplinary studies on algal physiology and genetics, marine hydrology, reproductive biology, and ecology.
A Hybrid MPC-PID Control System Design for the Continuous Purification and Processing of Active Pharmaceutical Ingredients
Authors: Sen Maitraye , Singh Ravendra , Ramachandran Rohit
Published: May 2014

In this work, a hybrid MPC (model predictive control)-PID (proportional-integral-derivative) control system has been designed for the continuous purification and processing framework of active pharmaceutical ingredients (APIs). The specific unit operations associated with the purification and processing of API have been developed from first-principles and connected in a continuous framework in the form of a flowsheet model. These integrated unit operations are highly interactive along with the presence of process delays. Therefore, a hybrid MPC-PID is a promising alternative to achieve the desired control loop performance as mandated by the regulatory authorities. The integrated flowsheet model has been simulated in gPROMSTM (Process System Enterprise, London, UK). This flowsheet model has been linearized in order to design the control scheme. The ability to track the set point and reject disturbances has been evaluated. A comparative study between the performance of the hybrid MPC-PID and a PID-only control scheme has been presented. The results show that an enhanced control loop performance can be obtained under the hybrid control scheme and demonstrate that such a scheme has high potential in improving the efficiency of pharmaceutical manufacturing operations.
Surveying Wearable Human Assistive Technology for Life and Safety Critical Applications: Standards, Challenges and Opportunities
Authors: Alam Muhammad , Hamida Elyes
Published: May 2014

In this survey a new application paradigm life and safety for critical operations and missions using wearable Wireless Body Area Networks (WBANs) technology is introduced. This paradigm has a vast scope of applications, including disaster management, worker safety in harsh environments such as roadside and building workers, mobile health monitoring, ambient assisted living and many more. It is often the case that during the critical operations and the target conditions, the existing infrastructure is either absent, damaged or overcrowded. In this context, it is envisioned that WBANs will enable the quick deployment of ad-hoc/on-the-fly communication networks to help save many lives and ensuring people’s safety. However, to understand the applications more deeply and their specific characteristics and requirements, this survey presents a comprehensive study on the applications scenarios, their context and specific requirements. It explores details of the key enabling standards, existing state-of-the-art research studies, and projects to understand their limitations before realizing aforementioned applications. Application-specific challenges and issues are discussed comprehensively from various perspectives and future research and development directions are highlighted as an inspiration for new innovative solutions. To conclude, this survey opens up a good opportunity for companies and research centers to investigate old but still new problems, in the realm of wearable technologies, which are increasingly evolving and getting more and more attention recently.
Comparative Study on a Solving Model and Algorithm for a Flush Air Data Sensing System
Authors: Liu Yanbin , Xiao Dibo , Lu Yuping
Published: May 2014

With the development of high-performance aircraft, precise air data are necessary to complete challenging tasks such as flight maneuvering with large angles of attack and high speed. As a result, the flush air data sensing system (FADS) was developed to satisfy the stricter control demands. In this paper, comparative stuides on the solving model and algorithm for FADS are conducted. First, the basic principles of FADS are given to elucidate the nonlinear relations between the inputs and the outputs. Then, several different solving models and algorithms of FADS are provided to compute the air data, including the angle of attck, sideslip angle, dynamic pressure and static pressure. Afterwards, the evaluation criteria of the resulting models and algorithms are discussed to satisfy the real design demands. Futhermore, a simulation using these algorithms is performed to identify the properites of the distinct models and algorithms such as the measuring precision and real-time features. The advantages of these models and algorithms corresponding to the different flight conditions are also analyzed, furthermore, some suggestions on their engineering applications are proposed to help future research.
Simulation-Based Learning Environments to Teach Complexity: The Missing Link in Teaching Sustainable Public Management
Authors: Deegan Michael , Stave Krystyna , MacDonald Rod , Andersen David , Ku Minyoung , Rich Eliot
Published: May 2014

While public-sector management problems are steeped in positivistic and socially constructed complexity, public management education in the management of complexity lags behind that of business schools, particularly in the application of simulation-based learning. This paper describes a Simulation-Based Learning Environment for public management education that includes a coupled case study and System Dynamics simulation surrounding flood protection, a domain where stewardship decisions regarding public infrastructure and investment have direct and indirect effects on businesses and the public. The Pointe Claire case and CoastalProtectSIM simulation provide a platform for policy experimentation under conditions of exogenous uncertainty (weather and climate change) as well as endogenous effects generated by structure. We discuss the model in some detail, and present teaching materials developed to date to support the use of our work in public administration curricula. Our experience with this case demonstrates the potential of this approach to motivate sustainable learning about complexity in public management settings and enhance learners’ competency to deal with complex dynamic problems.
Reporter Assay for Endo/Lysosomal Escape of Toxin-Based Therapeutics
Authors: Gilabert-Oriol Roger , Thakur Mayank , Von Mallinckrodt Benedicta , Bhargava Cheenu , Wiesner Burkhard , Eichhorst Jenny , Melzig Matthias , Fuchs Hendrik , Weng Alexander
Published: May 2014

Protein-based therapeutics with cytosolic targets are capable of exhibiting their therapeutic effect once they have escaped from the endosomes or lysosomes. In this study, the reporters—horseradish peroxidase (HRP), Alexa Fluor 488 (Alexa) and ricin A-chain (RTA)—were investigated for their capacity to monitor the endo/lysosomal escape of the ribosome-inactivating protein, saporin. The conjugates—saporin-HRP, Alexasaporin and saporin-KQ-RTA—were constructed, and the endo/lysosomal escape of these conjugates alone (lack of endo/lysosomal release) or in combination with certain structurally-specific triterpenoidal saponins (efficient endo/lysosomal escape) was characterized. HRP failed in reporting the endo/lysosomal escape of saporin. Contrastingly, Alexa Fluor 488 successfully allowed the report of the process at a toxin concentration of 1000 nM. In addition, single endo/lysosome analysis facilitated the determination of the amount of Alexasaporin released from each vesicle. RTA was also successful in reporting the endo/lysosomal escape of the enzymatically inactive mutant, saporin-KQ, but in this case, the sensitivity of the method reached a toxin concentration of 10 nM. In conclusion, the simultaneous usage of Alexa Fluor 488 and RTA as reporters may provide the possibility of monitoring the endo/lysosomal escape of protein-based therapeutics in the concentration range of 10–1000 nM.
Urologic Problems - Prenatal and Postnatal
Authors: Levine Milton I
Published: May 2014

A Pediatrician's View
Successful Treatment of Advanced Retinopathy of Prematurity
Authors: Topilow Harvey W , Ackerman Albert L , Wang Frederick M , Strome Robert R
Published: May 2014

ABSTRACT

Thirty-nine eyes of 20 premature infants, mean birth weight 922 g, mean gestational age 27 weeks, with active retinopathy of prematurity (ROP), were treated. Thirty-one eyes with stage 3+ ROP and 180° to 360° of preretinal neovascularization received cryotherapy to ablate the zone of peripheral avascular retina. All underwent complete regression of active disease. Eight of these eyes subsequently developed retinal detachments due to ongoing vitreous traction. One detachment was inoperable. Six eyes were successfully reattached following scleral buckling surgery. One of these six redetached and became inoperable after 20 months. Pars plicata vitrectomy was not successful in reattaching the eighth case. Twentyeight of these 31 eyes retain useful visual acuity with follow-up of 15 to 70 months (mean 41 months). There have been no complications resulting from cryotherapy.

Eight other eyes with stage 4 ROP (traction retinal detachment) were treated with cryotherapy and scleral buckling surgery. All were initially reattached, but ongoing v'rtreoretinal traction caused redetachment in five. One was inoperable. "Open sky" vitrectomy was successful in reattaching three of the other four. Of the six cases that remained reattached with follow-up of 6 to 51 months, only two retain useful vision.
Rotational Tarsal Conjunctival Flap in the Treatment of Scleral Necrosis
Authors: Rootman David S , Insler Michael S , Kaufman Herbert E
Published: May 2014

ABSTRACT

Scleral necrosis and perforation are difficult to manage. We describe a technique whereby a vascular strip of tarsal tissue with overlying conjunctiva can be rotated and sutured to a necrotic area of sclera that has been debrided, leading to rapid healing. The technique is performed easily, and can aid in the healing of areas of necrotic sclera that threaten perforation by providing a vascular pedicle.
A Pediatrician's View
Authors: Hoekelman Robert A
Published: May 2014

Do You Do Tympanocenteses?
Head Trauma and Its Sequelae
Authors: Johnston Michael V , Gerring Joan P
Published: May 2014

MICHAEL V. JOHNSTON, MD, and JOAN P. GERRING, MD
Delusions and Underlying Needs in Older Adults With Alzheimer’s Disease: Influence of Earlier Life Experiences and the Current Environment
Authors: Wang Jing-Jy , Cheng Wen-Yun , Lai Pei-Ru , Pai Ming-Chyi
Published: May 2014

Delusions are one of the most severe psychiatric symptoms of individuals with Alzheimer’s disease (AD), which often increase the stress experienced by caregivers. The purpose of this study was to understand the influences of earlier life experiences and the current environment on delusions, as well as the underlying needs of older adults with AD who experience delusions. Using an exploratory research design with a qualitative approach and purposive sampling, 20 family caregivers were interviewed. Two psychosocial types of attributes of delusion were categorized: Type A, the influence of earlier life experiences; and Type B, current environmental influences. The underlying needs of those with delusions include physical comfort, a desire to be secure, and a sense of belonging. The contents of delusions are easily influenced by patients’ earlier negative experiences and responsibilities, whereas the current environment exerts a crucial influence on the occurrence, frequency, and severity of specific delusions. These results can facilitate planning for patient-centered care by enhancing health care providers’ understanding of the psychosocial and environmental attributes and needs behind delusions. [
Journal of Gerontological Nursing, 40
(12), 38–47.]
Modeling and Simulation Analyses of Healthcare Delivery Operations for Inter-Hospital Patient Transfers
Authors: Chen Chialin , Zhao Samson X.
Published: May 2014

Inter-hospital transfers of patients for different elements of care have been increasingly used as a common strategy for providing quality healthcares through sharing limited resources worldwide. In this paper, the authors study the problem of healthcare delivery operations for inter-hospital patient transfers motivated by a real-world case within the South East Local Health Integration Network of Ontario. The authors use a directed graph to develop a general model for obtaining the solution that minimizes the overall transportation time while satisfying all the inter-hospital transfer requests with identical or different start and end points. The authors also perform simulation analyses to study the fleet sizing problem through evaluating different service performances with different fleet sizes. A number of implementation issues for managing inter-hospital patient transfer services are also discussed.
Numerical Simulation of Flow, Heat and Moisture Transfer in Heat and Moisture Exchanger (HME) Devices
Authors: Payami Seyed Pezhman , Behnia Masud , Dixon Barry , Santamaria John , Behnia Mehrdad
Published: May 2014

Heat and Moisture Exchanger (HME) is a simple solution to the problems of warming and humidification of inspired gases during ventilator treatment. The device acts as an “artificial” nose or passive humidifier, added to the breathing circuit to retain and exchange heat and moisture between inspiration and expiration. The HME traps expiratory heat and moisture from patient’s exhaled breath in a porous medium and returns a portion of them through the subsequent inspiratory cycle. The aim of our paper is to develop a computational fluid dynamics (CFD) model of an HME device commonly used in anaesthesia and intensive care. The CFD results allow a better understanding of flow behaviour leading to the design of more efficient devices. The CFD model solves the gas flow, heat and mass transfer equations in a DAR Hygrobac S (Mallinckrodt DAR, Mirandola, Italy). The temperature, absolute humidity and pressure fields are obtained during expiratory phase to evaluate heat and moisture conserving efficiencies and air flow resistance. The effect of flow rate as one of the major parameters in ventilator setting on temperature, humidity and pressure drop is determined. Inside the HME device, areas of recirculation are observed. As the flow rate increases the output temperature and absolute humidity go up causing a reduction in heat and moisture conserving capacities. Comparison of the CFD results with previously obtained experimental data shows a satisfactory agreement.
Investigation of the 3D Flow in Hemodialysis Venous Air Traps
Authors: Keshavarzi Gholamreza , Barber Tracie J. , Yeoh Guan Heng , Simmons Anne
Published: May 2014

Hemodialysis is an extracorporeal system which removes the waste product from kidneys for patients with kidney failure. Air bubbles within the system can cause several deficiencies to the system, and more importantly serious health issues to the patients. Therefore, different types of air traps (artery and venous side) are situated in the setup to prevent air bubbles passing through the system and being sent to the body. There have been evidence of the air trap deficiency. In order to understand these deficiencies the flow inside these air traps need to be understood. The investigation of the flow structures in air traps allow us to predict the efficiency of the air traps in capturing the air bubbles and preventing them from passing through. Computational fluid dynamic (CFD) has been used to compare the flow inside both these air traps. The results show interesting flow phenomena leading to explanations of the air bubble capturing effect.
CFD Flow Model and its Effects on the Calculations of High Pressure Sprays
Authors: Liu Lai Guo , Zhang Xiao Jun , Nie Song Lin
Published: May 2014

The computational fluid dynamics (CFD) model has been used to investigate the two-phase flow phenomena such as high-pressure water jet. High-pressure water jet is a new technology and develops rapidly due to its advantages in recent years. In this research, the effects of different models on the macroscopic parameters of jet propagation characteristics of high pressure water jet have been investigated numerically through the CFD technique. The simulations of the water jet with three kinds of k-ε models (i.e., standard, RNG, and realizable k-ε models) have been compared under the same conditions. It may be concluded that, the results calculated by the realizable k-epsilon model agree well with the experiment data and the realizable k-epsilon model would be utilized in the latter simulation. The agreement of the predicted data and experimental data are quite reasonable, it demonstrates that the CFD technique can be successfully applied to high-pressure water jet.
Application of Kriging to Motorsport Aerodynamic Analysis
Authors: Cruickshank Matthew , Doig Graham
Published: May 2014

Aerodynamic analysis in motorsport is conducted using three methods, computational, scaled experimental and full-scale operational. However, the varying fidelity, different sampling resolutions and unavoidable errors of each technique make valid comparisons between datasets from each method difficult and time consuming. Kriging is a geostatistical method to estimate values within a data field by examining and applying the trends of the dataset. This research examines how such techniques can be used to aid comparison between aerodynamic measurements of a race car. It examines how kriging can be used to transform discrete measurements, of varying fidelity and sampling resolution, into semi-continuous measurements, thus allowing computational results to be compared across a wider range of conditions than initially tested. This work explores how kriging can allow the trends from highly sampled data, such as track running, to be applied to less sampled data, such as CFD to improve computational and overall aerodynamic analysis.
Computational Simulation of an Altitude Adaptive Nozzle Concept
Authors: Schomberg K. , Doig Graham , Olsen J.
Published: May 2014

A computational analysis of an annular converging-diverging (CD) and an altitude adaptive expansion-deflection (ED) nozzle is presented. Numerical results were generated using a 2D axisymmetric, pressure-coupled solver in conjunction with the Spalart-Allmaras turbulence closure model and second order spatial discretisation schemes. Results were recorded over a theoretical altitude range and compared to experimental static pressure readings and schlieren images. The correlation between numerical and experimental static pressure values was high for all cases. Comparison of schlieren imagery outlined the large variety of flow regions within the ED nozzle flow field. The interactions between these regions were highly sensitive to turbulence and reinforced that conventional inviscid analytical techniques are unable to accurately describe behaviour within the ED nozzle flow field. The results highlight the salient effect of viscous effects within the ED nozzle flow field and justify a continued approach utilising computational fluid dynamics to increase understanding of the ED nozzle concept.
Explaining Ground Effect Aerodynamics via a Real-Life Reference Frame
Authors: Close Philip , Barber Tracie J.
Published: May 2014

The principle of relative motion as the cause of forces on a body submersedin a uid is foundational in the study of uid mechanics. In aerodynamics the wind tunnelis used as a convenient and safe method by which to test the aerodynamic performance ofbodies. This body-stationary convention has carried over into the computational world withthe development of CFD, though there is no practical reason why the moving body/stationaryuid set-up that corresponds to reality cannot be used for computational modelling. This pointbecomes particularly important as the concept of ground e ect is introduced. With an extraboundary nearby it becomes harder to appropriatel y match the experimental set-up with reality,and the extra boundary condition also adds complexity to computational simulation. A studywas undertaken to compare the body-stationary and body-moving reference frames in grounde ect. The moving reference frame velocity elds allowed new insight into the aerodynamics ofground e ect.
Analysis of Transient Bioheat Transfer in the Human Eye Using Hybrid Finite Element Model
Authors: Zhang Ze Wei , Wang Hui , Qin Qing Hua
Published: May 2014

Simulation of transient bioheat transfer in a two dimensional (2D) human eye model is conducted using a newly developed hybrid fundamental solution-finite element method (HFS-FEM) coupling with the radial basis function (RBF) approximation. Firstly, a time stepping scheme based on the finite difference method (FDM) is used to handle time variable in the transient Pennes bioheat equation. Secondly, the particular solution of the governing equation is approximated by a RBF approach. Then, the homogeneous solution is calculated by means of HFS-FEM. The obtained results are compared with those from ABAQUS and a good agreement between them is observed.
Comparing Contact Pressure Induced by a Conventional Complete Denture and an Implant-Retained Overdenture
Authors: Chen Jun Ning , Ahmad Rohana , Swain Michael V. , Li Wei , Suenaga Hanako , Li Qing
Published: May 2014

Implant-retained overdenture has been widely applied as a solution to edentulous ageing; however, a major concern for the denture wearers is bone resorption induced by the prosthetic interaction with soft tissue and bone. Early studies have revealed that the bone resorption is associated with the disturbance to the mucosa blood flow. This study aimed to investigate the contact pressure induced by an implant-retained overdenture, compared to a conventional complete denture without implants, which implies the potential bone resorption for clinical investigation. A three-dimensional finite element model of a full jaw, including mandible bone, mucosa, and denture, was created through a reverse engineering method based on CBCT images, in which the hyperelastic behaviour of mucosa was determined by curve-fitting to the clinical measurement, for a more realistic response. It is found that the location of the bone loss differed between the implant retained and non-implant complete dentures. With the implants, the denture displaced more at posterior ends towards the mucosa bearing area, leading to higher contact pressure accounted for more severe local bone loss.
Atoms to Assemblies: A Physics-Based Hierarchical Modelling Approach for Polymer Composite Components
Authors: Pearce Garth M. , Lim Shen Hin , Sul Jung Hoon , Prusty B. Gangadhara , Kelly Don W.
Published: May 2014

The development of new composite materials requires analysis and experimentation spanning scales from nanometres to metres, from “atoms to assemblies”. In this paper, concerned primarily with fibre reinforced epoxy composites, a methodology is presented which allows continuum level structural simulation to account for nanoand micro-scale size effects in composites. The novelty of this approach is the modular hierarchical nature of the simulation which ensures computational tractability, regardless of the length scales considered. Linking the nanoscale to the macroscopic scale in a single simulation allows for holistic materials development, including the addition of nanoadditives to polymer resin systems.
Analysis of Inclined Strip Anchors in Sand Based on the Block Set Mechanism
Authors: Yu S.B. , Hambleton J.P. , Sloan Scott William
Published: May 2014

Anchors are widely used in foundation systems for structures requiring uplift resistance. As demonstrated by numerous theoretical and experimental studies on the subject, uncertainty remains as to both the theoretical uplift capacity of anchors in idealised soils and the suitability of the various modelling assumptions in capturing the responses observed during tests. This study, which deals exclusively with the theoretical uplift capacity, presents newly obtained predictions of uplift capacities and the corresponding collapse mechanisms for inclined strip anchors in sand. The analysis is based on the upper bound (kinematic) method of limit analysis and the so-called block set mechanism, in which a collapse mechanism consisting of sliding rigid blocks is optimised with respect to interior angles and edges of the blocks. It is demonstrated that the method provides lower (better) estimates of uplift capacity in some cases compared to previous upper bound calculations. Also, variations in the predicted collapse mechanism with changes in embedment and inclination are assessed in detail.
Lateral Boundary Effect in Centrifuge Tests for Spudcan Penetration in Uniform Clay
Authors: Ullah Shah Neyamat , Hu Yu Xia , White David , Stanier Samuel
Published: May 2014

The effect of the centrifuge strongbox boundary on the penetration resistance of a spudcan foundation in uniform clay has been studied using Large Deformation FE analysis. Both smooth and rough strongbox boundaries were considered with various strongbox sizes. The spudcan penetration resistance and soil flow mechanisms were analysed. It was observed that, when the strongbox size was reduced, the spudcan penetration resistance was decreased for a smooth boundary and increased for a rough boundary. The depth of cavity formed above the spudcan during its penetration, in most cases, was determined by the soil flow around mechanism without cavity wall failure. However, cavity wall failure could be initiated when a smooth strongbox boundary was very close to the spudcan. The strongbox boundary effect on the spudcan penetration resistance can be avoided when the distance of the strongbox boundary to the spudcan centre is larger than 1.5 times of spudcan diameter for a rough boundary; or 2 times of spudcan diameter for a smooth boundary.
A Three Dimensional Plasticity Model for Sands Based on State Concept
Authors: Das Saumyasuchi , Bradley Brendon , Cubrinovski Misko
Published: May 2014

A three dimensional plasticity model for shear deformation in sand is developed based on the plane strain model of Cubrinovski and Ishihara [1]. The model uses a circular bounding surface. The model is hypoplastic in nature, rendering the principal directions of plastic strain increment different from those of the stress, and thus, allows for accumulation of plastic strain with principal stress rotation. The model uses the multi-surface based mixed hardening rule. This paper presents results from simulations under bi-directional (torsional-stress path) uniform stress cycles, as well as bi-directional stress-controlled simulation results, where two orthogonal horizontal components of a ground acceleration time series are converted to bi-directional stress history, providing a rigorous verification of the algorithm.
Isogeometric Boundary Element Method for the Simulation in Tunneling
Authors: Marussig Benjamin , Beer Gernot , Duenser Christian
Published: May 2014

Isogeometricfiniteelement methods and more recentlyboundaryelement methods have been successfully applied to problems in mechanical engineering and have led to an increased accuracy and a reduction in simulation effort. Isogeometric boundary element methods have great potential for the simulation of problems in geomechanics, especially tunneling because an infinite domain can be considered without truncation. In this paper we discuss the implementation of the method in the research software BEFE++. Based on an example of a spherical excavation we show that a significant reduction in the number of parameters for describing the excavation boundary as well as an improved quality of the results can be obtained.
Seismic Behaviour of RBS and AW-RBS Moment Resistant Connections in Double I-Beams
Authors: Sepasgozar Saleh Mohammad Ebrahimzadeh , Naghipour Morteza , Akbarnezhad Ali
Published: May 2014

Moment resistant steel connections are widely used in steel structures and play a significant role in reliability of structures, especially in earthquake-prone regions. After the Northridge earthquake, the invention of Reduced Beam Section (RBS) connections was a turning point in the design of the moment-resistant steel connections. In the present study, the seismic behavior of the RBS connections with reduced flange width as well as the AW-RBS connections with reduced web section in the double section beams are investigated. The results of a numerical study conducted using ABQUS finite element modeling software to investigate the ductility, energy absorption and plastic behavior of the RBS joints under cyclic loads are presented. Results showed promising performance with regards to energy absorbance and ductility for the AW-RBS connections.
FE Modelling of Storage Rack Frames
Authors: Sena Cardoso Francisco , Rasmussen Kim J.R.
Published: May 2014

This paper concerns storage rack frames and describes a study that led to the development of an FE model sufficiently accurate and simultaneously simple to be adopted by professional engineers. The presented FE model pays particular attention to storage rack frames susceptible to local/distortional buckling and down-aisle sway buckling. The influence of several strength parameters is also assessed with a special focus on the moment-rotation curve of the semi-rigid joints, including the detailed connection between members discretised into shell elements, and the modelling of perforations.
Modeling of Grained Heterogeneity with Voronoi Tessellation in Microforming Process
Authors: Fang Zhi , Jiang Zheng Yi , Wei Dong Bin
Published: May 2014

Microforming technology has attracted more and more attention because of its high utilization in almost every field. However, due to size effect, the conventional scale mechanical processing theories could not be applicable. Further, the characteristic of each single grain involved in the deformed area activates to play a significant role in the manufacturing process. In order to reflect and investigate the relationship among these grains better, this paper represents a pre-process modeling method with Voronoi tessellation to reveal the grained heterogeneity of workpiece numerically in order to obtain high accuracy and prediction result in finite element (FE) modelling of microforming process. Corresponding micro V-bending experiments have been carried out, and the experimental results are in good agreement with simulation results in terms of final angles after micro bending with consideration of springback.
Multi-Scale Overlapping Domain Decomposition to Consider Local Deformations in the Analysis of Thin-Walled Members
Authors: Erkmen R. Emre
Published: May 2014

Thin-walled members that have one dimension relatively large in comparison to the cross-sectional dimensions are usually modelled by using beam-column type finite element formulations. Beam-column elements however, are based on the assumption of rigid cross-section, thus they cannot consider the cross-sectional deformations such as local buckling and only allows considerations of the beam axis behaviour such as flexural or lateral-torsional buckling. Shell-type finite elements can be used to model the structure in order to consider these local deformation effects. Based on the Bridging multi-scale approach, this study proposes a numerical technique that is able to split the global analysis, which is performed by using simple beam-type elements, from the local analysis which is based on more sophisticated shell-type elements. As a result, the proposed multi-scale method allows the usage of shell elements in a local region to incorporate the local deformation effects on the overall behaviour of thin-walled members without necessitating a shell-type model for the whole member.
Modelling of Guided Wave Propagation with Spectral Element: Application in Structural Engineering
Authors: Wang Ying , Hao Hong
Published: May 2014

Among many structural health monitoring (SHM) methods, guided wave (GW) based method has been found as an effective and efficient way to detect incipient damages. In comparison with other widely used SHM methods, it can propagate in a relatively long range and be sensitive to small damages. Proper use of this technique requires good knowledge of the effects of damage on the wave characteristics. This needs accurate and computationally efficient modeling of guide wave propagation in structures. A number of different numerical computational techniques have been developed for the analysis of wave propagation in a structure. Among them, Spectral Element Method (SEM) has been proposed as an efficient simulation technique. This paper will focus on the application of GW method and SEM in structural health monitoring. The GW experiments on several typical structures will be introduced first. Then, the modeling techniques by using SEM are discussed.
Numerical Simulation of Free-Air Explosion Using LS-DYNA
Authors: Hashemi S.K. , Bradford Mark A.
Published: May 2014

The development of advanced computational technologies in recent years has seen studies of the effects of explosions on large structures becoming feasible and, as a consequence, the number of destructive tests and their high cost can be reduced significantly. This paper presents a study of air-burst explosion wave propagation using computational modelling based on LS-DYNA. Incident and reflected pressure waves are investigated, as well as the mesh sensitivity, different scaled distances and the charge shape. The Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) representation is used to model the blast, and the results are validated by empirical methods. The effects of parameter values adopted in these methods are studied. The results show that LS-DYNA can effectively simulate an air-burst explosion. Additionally, the mesh size and explosive weight have a large influence on the peak incident and reflected pressures. It is observed that there is an optimum range of the mesh size in relation to the explosive weight, material properties and the scaled distance which can significantly reduce the CPU usage while having reasonable accuracy. Different charge shapes cause different pressure distributions over the air domain.
Topology Optimisation of Composites Containing Base Materials of Distinct Poisson’s Ratios
Authors: Du Xu Ran , Xie Mike , Yang Xiao Ying , Zuo Zhi Hao
Published: May 2014

From recent studies on natural composites such as nacre and bone, it has shown that the mechanical properties of the composite are significantly affected by the Poisson’s ratio of each constituent phase. In some cases it is found that when the Poisson’s ratio approaches the incompressibility limit, the stiffness of the composite in one or more directions can increase dramatically, in some cases by two or more orders of magnitude than the softer phase. In this paper we investigate designing the composite of maximum stiffness by a topology optimisation approach. The method used is based on the bi-directional evolutionary structural optimisation (BESO). The Optimisation problem is formulated and it is solved by a searching algorithm based on the sensitivity analysis. The effect of interpolation function in the sensitivity analysis is studied. Examples of different combinations of Poisson’s ratios are presented. The stiffness is found to increase from its base value. In the case of one phase having negative Poisson’s ratio, the increase is very significant. It is concluded that the proposed method is effective in optimising the stiffness of this class of composite.
Development of a Hypersonic Aircraft Design Optimization Tool
Authors: Morrell Benjamin J. , Munk David J. , Vio Gareth A. , Verstraete Dries
Published: May 2014

The design and optimization of hypersonic aircraft is severely impacted by the high temperatures encountered during flight as they can lead to high thermal stresses and a significant reduction in material strength and stiffness. This reduction in rigidity of the structure requires innovative structural concepts and a stronger focus on aeroelastic deformations in the early design and optimisation of the aircraft structure. This imposes the need for a closer coupling of the aerodynamic and structural design tools than is current practice. The paper presents the development of a multi-disciplinary, closely coupled optimisation suite for hypersonic aircraft. An overview of the setup and structure of the optimization suite is given and the integration between the Tranair solver, used to determine the aerodynamic loads and temperatures, and MSC/NASTRAN, used for the structural sizing and design, will be given.
A Variable Diffusivity Model for the Drying of Spherical Food Particulates
Authors: Walker Lauren , Senadeera Wijitha
Published: May 2014

An investigation of the drying of spherical food particles was performed, using peas as the model material. In the development of a mathematical model for drying curves, moisture diffusion was modelled using Fick’s second law for mass transfer. The resulting partial differential equation was solved using a forward-time central-space finite difference approximation, with the assumption of variable effective diffusivity. In order to test the model, experimental data was collected for the drying of green peas in a fluidised bed at three drying temperatures. Through fitting three equation types for effective diffusivity to the data, it was found that a linear equation form, in which diffusivity increased with decreasing moisture content, was most appropriate. The final model accurately described the drying curves of the three experimental temperatures, with an R2value greater than 98.6% for all temperatures.
Connecting Rod Machining Process Improvement
Authors: Sun De Ying
Published: May 2014

connecting rod parts except under larger dynamic load in the institutions, it is also connected with other parts, movement and direction, therefore, the part of the connecting rod connected with other parts on the machining accuracy is crucial. In this paper, analysis and study connecting rod machining process, through the improvement plan, ensure the accuracy of the important parts of the connecting rod parts and the connecting rod production and processing efficiency.
Structural Analysis of Unloading Frame of Mine Tubular Belt Conveyor
Authors: Ma Qi Jiang , Wang Kai Song , Li Fei Fei
Published: May 2014

Mine tubular belt conveyor is a special belt-conveyor which uses closed transportation way to transport material, Unloading frame is one of the important structures of its unloading device, and its structural strength affect the running conditions of the machine. For this purpose, based on a certain type of mine tubular belt conveyor, this paper introduced the structure design and force calculation of its unloading frame, and took structural strength and stiffness analysis by ANSYS. Analysis results showed that Unloading frame meet the design requirements, but for ensuring the normal operation of the machine, the welding quality of unloading frame should also be considered.
Foundry Technique Designing and Optimization of the Cast-Steel Casting
Authors: He Bin Feng
Published: May 2014

The traditional method has been used to the foundry technique for the cast-steel casting. And the commercial foundry simulation software was used to validate the rationality of the foundry technique. Four side risers and some cylindrical chills were used to decrease the shrinkages which would occur in casting. The results show that the risers could not feed the casting effectively because of the limited feeding distance. A top riser was introduced to eliminate the defects, the simulation results show that still some shrinkages occurred because the heat effect between risers. The side risers were replaced by an annular chill. Finally, the shrinkages would happened in casting were eliminated.
Nonlinear Dynamic Analysis of Low Pressure Rotor of High Parameter Turbine by Improved Segment Direct Integration Method
Authors: Shi Guang Tian
Published: May 2014

Based on time precise integration method, an improved precise integration method, which called, is studied in the paper to solve the dynamic equation of , where v is an unknown n dimensions vector, Hv and f are respectively the linear homogeneous part and nonlinear part on the right end of equation. Then the calculation expressions of the method are given. The numerical example of nonlinear dynamic analysis of low pressure rotor of high parameter turbine shows that the proposed method is no need to solve the H-1 and the computational accuracy and efficiency can be ensured.
Air-Hydraulic Intensifier Equipment and Technology Research of Clinching
Authors: Zhao Yong Qiang , Zhao Sheng Dun , Xu Fan , Han Xiao Lan , Zhao Ren Feng
Published: May 2014

Base on clinching process, an air-hydraulic intensifier clinching devices was designed. In order to accurately control the quality of clinching, the displacement sensor and pressure sensor were joined in the control loop. So two different control feedback loops were founded. With two different ways of clinching tests, a clinching test method was founded, and the joint strength is analyzed. The result was that the shears strength and fracture strength in different directions of clinching samples are different.
An Electric Vehicle (EV) Side Pole Collision Test Research
Authors: Zhu Hai Tao , Ji Yi , Zhong Yan Hui
Published: May 2014

Electric vehicle (EV) maybe exist electricity leakage phenomenon during the side pole impact. so it not only to be meet the requirements of occupant protection, but also to be meet the requirements of electric safety. In this paper, according to the relevant standards, An electric vehicle side collision column test was done. It was pointed out that the EV design shortcomings and put forward the improvement direction by the test results analysis.