bluuebunny/crossref_metadata_2025 huggingface dataset:
New Energy-Conserved Identitiesand Super-Convergence of the Symmetric Ec-S-Fdtd Scheme for Maxwell’s Equations in 2D
Authors: Gao Liping , Liang Dong
Published: May 2012

The symmetric energy-conserved splitting FDTD scheme developed in is a very new and efficient scheme for computing the Maxwell’s equations. It is based on splitting the whole Maxwell’s equations and matching the x-direction and y-direction electric fields associated to the magnetic field symmetrically. In this paper, we make further study on the scheme for the 2D Maxwell’s equations with the PEC boundary condition. Two new energy-conserved identities of the symmetric EC-S-FDTD scheme in the discrete H1-norm are derived. It is then proved that the scheme is uncondi-tionally stable in the discrete H1-norm. By the new energy-conserved identities, the super-convergence of the symmetric EC-S-FDTD scheme is further proved that it is of second order convergence in both time and space steps in the discrete H1-norm. Numerical experiments are carried out and confirm our theoretical results.
Adaptive Cloud Refinement (ACR) - Adaptation in Meshless Framework
Authors: Somasekhar M. , Vivek S. , Malagi Keshav. S. , Ramesh V. , Deshpande S. M.
Published: May 2012

In the present work adaptation in meshless framework is proposed. The grid adaptation or mesh adaptation is quite well developed area in case of conventional grid based solvers and is popularly known as Adaptive mesh refinement (AMR). In such cases the adaptation is done by subdividing the cells or elements into finer cells or elements. In case of meshless methods there are no cells or elements but only a cloud of points. In this work we propose to achieve the meshless adaptation by locally refining the point density in the regions demanding higher resolution. This results into an adaptive enriched cloud of points. We call this method as Adaptive Cloud Refinement (ACR). The meshless solvers need connectivity information, which is a set of neighboring nodes. It is crucial part of meshless solvers. Obviously because of refining point density, the connectivity of nodes in such regions gets modified and hence has to be updated. An efficient connectivity update must exploit the fact that the node distribution would be largely unaffected except the region of adaptation. Hence connectivity updating needs to be done locally, only in these regions. In this paper we also present an extremely fast algorithm to update connectivity over adapted cloud called as ACU (Automatic Connectivity Update).
A Novel Dynamic Quadrature Scheme for Solving Boltzmann Equation with Discrete Ordinate and Lattice Boltzmann Methods
Authors: Hsu C. T. , Chiang S. W. , Sin K. F.
Published: May 2012

The Boltzmann equation (BE) for gas flows is a time-dependent nonlinear differential-integral equation in 6 dimensions. The current simplified practice is to linearize the collision integral in BE by the BGK model using Maxwellian equilibrium distribution and to approximate the moment integrals by the discrete ordinate method (DOM) using a finite set of velocity quadrature points. Such simplification reduces the dimensions from 6 to 3, and leads to a set of linearized discrete BEs. The main difficulty of the currently used (conventional) numerical procedures occurs when the mean velocity and the variation of temperature are large that requires an extremely large number of quadrature points. In this paper, a novel dynamic scheme that requires only a small number of quadrature points is proposed. This is achieved by a velocity-coordinate transformation consisting of Galilean translation and thermal normalization so that the transformed velocity space is independent of mean velocity and temperature. This enables the efficient implementation of Gaussian-Hermite quadrature. The velocity quadrature points in the new velocity space are fixed while the correspondent quadrature points in the physical space change from time to time and from position to position. By this dynamic nature in the physical space, this new quadrature scheme is termed as the dynamic quadrature scheme (DQS). The DQS was implemented to the DOM and the lattice Boltzmann method (LBM). These new methods with DQS are therefore termed as the dynamic discrete ordinate method (DDOM) and the dynamic lattice Boltzmann method (DLBM), respectively. The new DDOM and DLBM have been tested and validated with several testing problems. Of the same accuracy in numerical results, the proposed schemes are much faster than the conventional schemes. Furthermore, the new DLBM have effectively removed the incompressible and isothermal restrictions encountered by the conventional LBM.
On Computational Modelling Of Strain-Hardening Material Dynamics
Authors: Barton Philip , Romenski Evgeniy
Published: May 2012

In this paper we show that entropy can be used within a functional for the stress relaxation time of solid materials to parametrise finite viscoplastic strain-hardening deformations. Through doing so the classical empirical recovery of a suitable irreversible scalar measure of work-hardening from the three-dimensional state parameters is avoided. The success of the proposed approach centres on determination of a rate-independent relation between plastic strain and entropy, which is found to be suitably simplistic such to not add any significant complexity to the final model. The result is sufficiently general to be used in combination with existing constitutive models for inelastic deformations parametrised by one-dimensional plastic strain provided the constitutive models are thermodynamically consistent. Here a model for the tangential stress relaxation time based upon established dislocation mechanics theory is calibrated for OFHC copper and subsequently integrated within a two-dimensional moving-mesh scheme. We address some of the numerical challenges that are faced in order to ensure successful implementation of the proposedmodel within a hydrocode. The approach is demonstrated through simulations of flyer-plate and cylinder impacts.
A Constrained Level Set Method for Simulating the Formation of Liquid Bridges
Authors: He Dongdong , Huang Huaxiong
Published: May 2012

In this paper, we investigate the dynamic process of liquid bridge formation between two parallel hydrophobic plates with hydrophilic patches, previously studied in [1]. We propose a dynamic Hele-Shaw model to take advantage of the small aspect ratio between the gap width and the plate size. A constrained level set method is applied to solve the model equations numerically, where a global constraint is imposed in the evolution [2] stage together with local constraints in the reinitialization [3] stage of level set function in order to limit numerical mass loss. In contrast to the finite element method used in [2], we use a finite difference method with a 5th order HJWENO scheme for spatial discretization. To illustrate the effectiveness of the constrained method, we have compared the results obtained by the standard level set method with those from the constrained version. Our results show that the constrained level set method produces physically reasonable results while that of the standard method is less reliable. Our numerical results also show that the dynamic nature of the flow plays an important role in the process of liquid bridge formation and criteria based on static energy minimization approach has limited applicability.
Inertial Frame Independent Forcing for Discrete Velocity Boltzmann Equation: Implications for Filtered Turbulence Simulation
Authors: Premnath Kannan N. , Banerjee Sanjoy
Published: May 2012

We present a systematic derivation of a model based on the central moment lattice Boltzmann equation that rigorously maintains Galilean invariance of forces to simulate inertial frame independent flow fields. In this regard, the central moments, i.e. moments shifted by the local fluid velocity, of the discrete source terms of the lattice Boltzmann equation are obtained by matching those of the continuous full Boltzmann equation of various orders. This results in an exact hierarchical identity between the central moments of the source terms of a given order and the components of the central moments of the distribution functions and sources of lower orders. The corresponding source terms in velocity space are then obtained from an exact inverse transformation due to a suitable choice of orthogonal basis for moments. Furthermore, such a central moment based kinetic model is further extended by incorporating reduced compressibility effects to represent incompressible flow. Moreover, the description and simulation of fluid turbulence for full or any subset of scales or their averaged behavior should remain independent of any inertial frame of reference. Thus, based on the above formulation, a new approach in lattice Boltzmann framework to incorporate turbulence models for simulation of Galilean invariant statistical averaged or filtered turbulent fluid motion is discussed.
A Coupled Approach for Fluid Dynamic Problems Using the PDE Framework Peano
Authors: Neumann Philipp , Bungartz Hans-Joachim , Mehl Miriam , Neckel Tobias , Weinzierl Tobias
Published: May 2012

We couple different flow models, i.e. a finite element solver for the Navier-Stokes equations and a Lattice Boltzmann automaton, using the framework Peano as a common base. The new coupling strategy between the meso- and macroscopic solver is presented and validated in a 2D channel flow scenario. The results are in good agreement with theory and results obtained in similar works by Latt et al. In addition, the test scenarios show an improved stability of the coupled method compared to pure Lattice Boltzmann simulations.
High Efficient Numerical Simulation of Infrared Radiation from a Hot Exhaust Nozzle
Authors: Hu Haiyang , Bai Peng , Wang Qiang
Published: May 2012

A coupled model, capable of simulating transonic flow, solid heat conduction, species transport, and gas radiation, is developed that provides better computational treatment of infrared radiation from hot exhaust nozzles. The modeling of gas radiation is based on a statistical narrow-band correlated-k analysis, whose parameters are deduced from the HITEMP line-by-line database. To improve computational efficiency, several methods are employed. A mixed analytical-numerical algorithm is described for the stiffness of the two-equation turbulence model and an alternating direction implicit pretreatment for the ill-conditioned matrix appearing in the coupled problem of flow and solid heat conduction. Moreover, an improved multigrid method and a symmetry plane treatment of the radiation transfer-energy equations are also introduced. Four numerical simulations are given to confirm the efficiency and accuracy of the numerical method. Finally, an account of the aerothermodynamics and infrared characteristics for two types of nozzles are presented. The infrared radiation intensity of the Chevron ejecting nozzle is clearly smaller than that of the common axisymmetric ejecting nozzle. All computations can be performed on a personal computer.
Modified Upwinding Compact Scheme for Shock and Shock Boundary Layer Interaction
Authors: Liu Chaoqun , Lu Ping , Oliveira Maria , Xie Peng
Published: May 2012

Standard compact scheme and upwinding compact scheme have high order accuracy and high resolution, but cannot capture the shock which is a discontinuity. This work developed a modified upwinding compact scheme which uses an effective shock detector to block compact scheme to cross the shock and a control function to mix the flux with WENO scheme near the shock. The new scheme makes the original compact scheme able to capture the shock sharply and, more importantly, keep high order accuracy and high resolution in the smooth area which is particularly important for shock boundary layer and shock acoustic interactions. Numerical results show the scheme is successful for 2-D Euler and 2-D Navier-Stokes solvers. The examples include 2-D incident shock, 2-D incident shock and boundary layer interaction. The scheme is robust, which does not involve case related parameters.
Fast Multipole Accelerated Boundary Integral Equation Method for Evaluating the Stress Field Associated with Dislocations in a Finite Medium
Authors: Zhao Degang , Huang Jingfang , Xiang Yang
Published: May 2012

In this paper, we develop an efficient numerical method based on the boundary integral equation formulation and new version of fast multipole method to solve the boundary value problem for the stress field associated with dislocations in a finite medium. Numerical examples are presented to examine the influence from material boundaries on dislocations.
High Order Schemes on Three-Dimensional General Polyhedral Meshes — Application to the Level Set Method
Authors: Pringuey Thibault , Cant R. Stewart
Published: May 2012

In this article, we detail the methodology developed to construct arbitrarily high order schemes — linear and WENO — on 3D mixed-element unstructured meshes made up of general convex polyhedral elements. The approach is tailored specifically for the solution of scalar level set equations for application to incompressible two-phase flow problems. The construction of WENO schemes on 3D unstructured meshes is notoriously difficult, as it involves a much higher level of complexity than 2D approaches. This due to the multiplicity of geometrical considerations introduced by the extra dimension, especially on mixed-element meshes. Therefore, we have specifically developed a number of algorithms to handle mixed-element meshes composed of convex polyhedra with convex polygonal faces. The contribution of this work concerns several areas of interest: the formulation of an improved methodology in 3D, the minimisation of computational runtime in the implementation through the maximum use of pre-processing operations, the generation of novel methods to handle complex 3D mixed-element meshes and finally the application of the method to the transport of a scalar level set.
A Spectral Iterative Method for the Computation of Effective Properties Of Elastically Inhomogeneous Polycrystals
Authors: Bhattacharyya Saswata , Heo Tae Wook , Chang Kunok , Chen Long-Qing
Published: May 2012

We report an efficient phase field formalism to compute the stress distribution in polycrystalline materials with arbitrary elastic inhomogeneity and anisotropy The dependence of elastic stiffness tensor on grain orientation is taken into account, and the elastic equilibrium equation is solved using a spectral iterative perturbation method. We discuss its applications to computing residual stress distribution in systems containing arbitrarily shaped cavities and cracks (with zero elastic modulus) and to determining the effective elastic properties of polycrystals and multilayered composites.
Computer Simulation of Helium Effects in Plutonium During the Aging Process of Self-Radiation Damage
Authors: Ao Bingyun , Chen Piheng , Shi Peng , Wang Xiaolin , Hu Wangyu , Wang Liang
Published: May 2012

Due to α radioactive decay Pu is vulnerable to aging. The behavior of He in Pu is the foundation for understanding Pu self-radiation damage aging. Molecular dynamics technique is performed to investigate the behavior of defects, the interaction between He and defects, the processes of initial nucleation and growth of He bubble and the dependence of He bubble on the macroscopical properties of Pu. Modified embedded atom method, Morse pair potential and the Lennard-Jones pair potential are used for describing the interactions of Pu-Pu, Pu-He and He-He, respectively. The main calculated results show that He atoms can combine with vacancies to form Hevacancy cluster (i.e., the precursor of He bubble) during the process of self-radiation as a result of high binding energy of an interstitial He atom to vacancy; He bubble’s growth can be dominated by the mechanism of punching out of dislocation loop; the swelling induced by He bubble is very small; grain boundaries give rise to an energetically more favorable zone for the interstitial He atom and self-interstitial atom accumulation than for vacancy accumulation; the process of He release can be identified as the formation of release channel induced by the cracking of He bubble and surface structure.
Runge-Kutta Discontinuous Galerkin Method Using Weno-Type Limiters: Three-Dimensional Unstructured Meshes
Authors: Zhu Jun , Qiu Jianxian
Published: May 2012

This paper further considers weighted essentially non-oscillatory (WENO) and Hermite weighted essentially non-oscillatory (HWENO) finite volume methods as limiters for Runge-Kutta discontinuous Galerkin (RKDG) methods to solve problems involving nonlinear hyperbolic conservation laws. The application discussed here is the solution of 3-D problems on unstructured meshes. Our numerical tests again demonstrate this is a robust and high order limiting procedure, which simultaneously achieves high order accuracy and sharp non-oscillatory shock transitions.
Evaluation of atmosphere-biosphere exchange estimations with TCCON measurements
Authors: Messerschmidt J. , Parazoo N. , Deutscher N. M. , Roehl C. , Warneke T. , Wennberg P. O. , Wunch D.
Published: May 2012

Abstract. Three estimates of the atmosphere-biosphere exchange are evaluated using Total Carbon Column Observing Network (TCCON) measurements. We investigate the Carnegie-Ames-Stanford Approach (CASA), the Simple Biosphere (SiB) and the GBiome-BGC models transported by the GEOS-Chem model to simulate atmospheric CO2 concentrations for the time period between 2006 and 2010. The CO2 simulations are highly dependent on the choice of the atmosphere-biosphere model and large-scale errors in the estimates are identified through a comparison with TCCON data. Enhancing the CO2 uptake in the boreal forest by 40% and shifting the onset of the growing season significantly improve the simulated seasonal CO2 cycle using CASA estimates. The SiB model gives the best estimate for the atmosphere-biosphere exchange in the comparison with TCCON measurements.
Coccolithophore surface distributions in the North Atlantic and their modulation of the air-sea flux of CO2 from 10 years of satellite Earth observation data
Authors: Shutler J. D. , Land P. E. , Brown C. W. , Findlay H. S. , Donlon C. J. , Medland M. , Snooke R. , Blackford J. C.
Published: May 2012

Abstract. Coccolithophores are the primary oceanic phytoplankton responsible for the production of calcium carbonate (CaCO3). These climatically important plankton play a key role in the oceanic carbon cycle as a major contributor of carbon to the open ocean carbonate pump (~50%) and their formation can affect the atmosphere-to-ocean (air-sea) uptake of carbon dioxide (CO2) through increasing the seawater partial pressure of CO2 (pCO2). Here we document variations in the areal extent of surface blooms of the globally important coccolithophore, Emiliania huxleyi, in the North Atlantic over a 10-year period (1998–2007), using Earth observation data from the Sea-viewing Wide Field of view Sensor (SeaWiFS). We calculate the annual mean surface areal coverage of E. huxleyi in the North Atlantic to be 474 000 ± 119 000 km2 yr−1, which results in a net CaCO3 production of 0.62 ± 0.15 Tg CaCO3 carbon per year. However, this surface coverage and net production can fluctuate by −54/+81% about these mean values and are strongly correlated with the El Niño/Southern Oscillation (ENSO) climate oscillation index (r = 0.75, p < 0.02). Our analysis evaluates the spatial extent over which the E. huxleyi blooms in the North Atlantic can increase the pCO2 and thus decrease the localised sink of atmospheric CO2. In regions where the blooms are prevalent, the average reduction in the monthly CO2 sink can reach 12%. The maximum reduction of the monthly CO2 sink in the time series is 32%. This work suggests that the high variability, frequency and distribution of these calcifying plankton and their impact on pCO2 should be considered within modelling studies of the North Atlantic if we are to fully understand the variability of its air-to-sea CO2 flux.
Surgical Treatment Modalities for Complicated Aneurysms and Pseudoaneurysms of Arteriovenous Fistulas
Authors: Belli Sedat , Parlakgumus Alper , Colakoglu Tamer , Ezer Ali , Yildirim Sedat , Moray Gokhan , Haberal Mehmet
Published: May 2012

Purpose

This study was designed to determine the clinical presentation, characteristics, and management of aneurysm/pseudoaneurysm formation (APF) in dialysis access fistulas.

Methods

The treatment methods and outcomes of 31 patients who underwent surgery for APF in dialysis access fistulas were retrospectively reviewed over a 9-year period.

Results

We performed 1558 operations for arteriovenous fistulas (AVFs) between 2000 and 2009 at our centre. Of the 1558 operations, 35 were carried out for APFs (2.2%) on 31 patients. Thirty of these operations were restorative. Twenty-two (71%) of these patients had their original access done elsewhere, and all corrective surgeries were performed at our hospital. Approximately 52% of the subjects were female, with a mean age of 45.7 ± 17 years. The mean duration of end-stage renal disease was 70.2 ± 51.5 months. The mean number of AVFs per patient was 2.2 ± 1.5. Synthetic grafts were used in five patients (16.1%). Most of the procedures were left-sided (67.7%) and brachial-cephalic fistulas (48.3%). Among 31 complications, 22 were arterial/venous aneurysms (71%) and nine were pseudoaneurysms (29%). Fourteen patients (46.6%) were treated by excision of the aneurysm and primary suture repair. The post-intervention primary patencies for all revised APFs were 68%, 56%, and 52% at 1, 6, and 12 months, respectively. Dysfunction of AVF (16.1%) and bleeding (12.9%) were the most encountered complications after aneurysmectomy.

Conclusion

Reformative operations should be considered in cases of urgency and irresponsiveness to endovascular surgery rather than closing the fistulas directly, as it prolongs the duration of AVF patency.
Proportioning Cats and Rats
Authors: Markworth Kimberly A.
Published: May 2012

This feline-rodent problem helps preservice teachers go beyond the cross-multiplication algorithm to think about proportional relationships.
Developing Formal Procedures through Sense Making
Authors: Choppin Jeffrey M. , Clancy Carolyn B. , Koch Scott J.
Published: May 2012

Allowing students to reason and communicate about integer operations, or any idea, before these ideas are formalized can be an important tool for fostering deep understanding.
Talking about the Greek Cross
Authors: Reeder Stacy L. , Abshire George E.
Published: May 2012

Meaningful discourse occurs when tasks are chosen carefully and when the teacher steps back and allows students to move to the forefront of their own learning.
A Super Way to Soak in Linear Measurement
Authors: Kurz Terri L.
Published: May 2012

After analyzing advertising claims regarding water shooters, students present their findings.
Advances in the electrical stunning and bleeding of ostriches
Authors: Hoffman LC
Published: May 2012

The stunning of ostriches (Struthio camelus) has traditionally been carried out with hand-held tongs whilst birds are held in a restraining area by applying pressure normally from behind by gently pushing on the tail feathers. The area is often a V-shaped structure, high enough that the stunning operator is not kicked. After stunning, the birds are rocked backwards and a rubberised leg clamp placed over the legs at the tarso-metatarsal bone allowing the birds to be chain-shackled by the big toes. This stunning procedure has been replaced by a new restraining and stunning mechanism which completely envelops the ostrich in a padded clamp holder. Double-padded sides restrain the bird's upper thighs and a rubberised foot clamp holds the feet so there is no physical damage to the bird. As the bird is electrically stunned with electrodes placed both sides of the head, the entire stunning box rotates 180° so that toe clamps can be applied without any danger to the stunning operators. Within 20 s of stunning, the birds are bled by means of a complete ventral cut to the neck and/or by thoracic sticking.
Evidence for pain in decapod crustaceans
Authors: Elwood RW
Published: May 2012

Vast numbers of decapods are used in human food and currently subject to extreme treatments and there is concern that they might experience pain. If pain is indicated then a positive change in the care afforded to this group has the potential to produce a major advance in animal welfare. However, it is difficult to determine pain in animals. The vast majority of animal phyla have a nociceptive ability that enables them to detect potential or actual tissue damage and move away by a reflex response. In these cases there is no need to assume an unpleasant feeling that we call pain. However, various criteria have been proposed that might indicate pain rather than simple nociception. Here, with respect to decapod crustaceans, four such criteria are discussed: avoidance learning, physiological responses, protective motor reactions and motivational trade-offs. The evidence from various experiments indicates that all four criteria are fulfilled and the data are thus consistent with the idea of pain. The responses cannot be explained by nociception alone but, it is still difficult to state categorically that pain is experienced by decapods. However, the evidence is as strong for this group as it is for fish but the idea that fish experience pain has broader acceptance than does the idea of decapod pain. A taxonomic bias is evident in the evaluation of experimental data.
Auditing animal welfare and making practical improvements in beef-, pork- and sheep-slaughter plants
Authors: Grandin T
Published: May 2012

A welfare audit that utilises numerically scored, animal-based outcome measures has been used successfully by McDonald's and other restaurant companies for over ten years. In 2010, audit data from two restaurant companies indicated that all 30 of their North American plants rendered 95% or more of the cattle insensible with a single shot from a captive-bolt gun. Eight pork plants that used electrical stunning placed the tongs correctly on 99% or more of the pigs. All animals were insensible prior to hoisting. In 32 beef plants, the percentage of cattle vocalising in the stunning area was 5% or less. In 94% of the beef plants and 86% of the pork plants, none of the animals fell during handling. The worst falling score was 2% in two of the plants. High standards were attained by making simple changes. To improve welfare, plant managers did the following: improved stunner maintenance; installed non-slip floors in stun boxes and unloading ramps; and trained employees. To reduce balking and improve animal movement, the following modifications were made: illumination of dark race entrances; moving of lamps to eliminate reflections; reducing equipment noise; stopping employee yelling; installation of solid sides on races or shields to prevent animals from seeing activity outside the facility; and the elimination of air blowing in the faces of approaching animals. Employees were trained to use behavioural principles of animal handling such as the point of balance and the flight zone. The five numerically scored outcome measures in this audit are critical control points that can detect a variety of problems. They are: i) the percentage of animals stunned effectively with a single application of the stunner; ii) the percentage of animals falling during handling must be 1% or less to pass; iii) the percentage of pigs or cattle vocalising (moo, bellow, squeal) in the stun box or while entering into the stun box must be 5% or less to pass (vocalisation scoring is not used for sheep); iv) the percentage of animals moved with an electric goad; and v) the percentage of animals rendered insensible before hoisting must be 100% to pass an audit. An animal is scored as either silent or as a vocaliser and whether stunned correctly with a single application or not stunned correctly. The audit also contains a list of banned practices that will result in an automatic failure. To maintain improvements in handling, 23 plants have installed video cameras that are monitored by auditors viewing the footage over the internet. These external auditors perform numerical scoring at random times throughout the day. Video auditing over the internet is an important new tool for improving welfare.
Preliminary evaluation of the effectiveness of captive-bolt guns as a killing method without exsanguination for horned and unhorned sheep
Authors: Gibson TJ , Ridler AL , Lamb CR , Williams A , Giles S , Gregory NG
Published: May 2012

The current study aims to make welfare-based recommendations for gun/cartridge combinations and shooting positions that will ensure death of the sheep (horned, unhorned, rams and ewes), without the need for either sticking or pithing. The study examined the pathophysiology of captive-bolt gun (CBG) injuries that result in incomplete concussion leading to death. Behavioural, brainstem and cranial/spinal responses were examined along with gross pathology in 489 animals (116 polled ewes, 134 horned ewes, 117 polled rams and 122 horned rams) following a variety of CBG-cartridge combinations. Shooting horned rams was more challenging than unhorned sheep, partly because minor movements of the head at the time of shooting can result in deflection of the gun by the horns. Marksmanship was the definitive factor: 100% of animals that showed signs of incomplete concussion were found to have been shot incorrectly. The findings will have application when it is necessary to kill sheep on farms for disease control or euthanasia purposes.
Stress at slaughter in cattle: role of reactivity profile and environmental factors
Authors: Terlouw EMC , Bourguet C , Deiss V
Published: May 2012

During slaughter, cattle may be exposed to many potentially stress-inducing factors, of emotional and physical nature. A series of studies aimed to identify factors that may contribute to slaughter stress. During reactivity tests testing emotional stressors, Blond d’Aquitaine bulls were more reactive than Angus and Limousin bulls. However, no breed differences were found for stress indicators at slaughter. Indicators of post mortem (PM) muscle metabolism were correlated with stress reactions at slaughter, and with behavioural reactions and heart rates during the reactivity tests, including a sudden event and handling. Similarly, in Normand cull cows, stronger behavioural and physiological reactions during the slaughter procedure were associated with faster PM muscle metabolism. Reactions during the reactivity tests were also correlated with stress indicators at slaughter. A Principal Component Analysis indicated that the first and second axes were correlated with reactions to non-familiarity and to social isolation, respectively. Both axes were correlated with stress indicators at slaughter, suggesting that these two aspects contribute significantly to the emotional stress at slaughter. These experiments indicate that stress reactivity at slaughter may be predicted from behavioural and emotional stress reactions during reactivity tests. A third experiment found that compared with normally fed cows, 30-h food-deprived cows showed stronger startle and fear responses in response to a sudden event. Within a group subjected to a physical-effort treatment, compared to normally fed heifers, food-deprived heifers were more reactive to human exposure. This shows that the reactions to a given stressor may increase due to the presence of other stressors. Thus, in cattle, novelty, social disturbances and sudden events may contribute to slaughter stress and the simultaneous presence of several stressors during the slaughter period may exacerbate stress reactions.
Veterinary certificates for emergency or casualty slaughter bovine animals in the Republic of Ireland: are the welfare needs of certified animals adequately protected?
Authors: Cullinane M , O’Sullivan E , Collins G , Collins DM , More SJ
Published: May 2012

All emergency and casualty bovines in the Republic of Ireland that are deemed to be fit for human consumption must be accompanied to the slaughterhouse by an official veterinary certificate (VC). Cullinane et al (2010) conducted a review of bovine cases consigned under veterinary certification to emergency (ES) and casualty (CS) slaughter in the Republic of Ireland during 2006 to 2008. The current paper further evaluates these results, with emphasis on the period of validity, transport distance and transport conditions, and considers whether the current VC adequately protects welfare. Of 1,255 veterinary certificates, the median time between certification and slaughter was 1 (minimum 0, maximum 452) day, with one-fifth in excess of three days. The median straight-line distance between farm and slaughterhouse was 22 km; 82 and 98% study animals were transported distances of no more than 40 and 100 km, respectively. In 27% of VCs, no slaughterhouse was designated; hence the transport distance was not limited. In 77% of all cases, the disability/injury was related to the locomotor system, including 35% with limb fractures. Veterinary certification of the latter as being fit for transport appears to have been in contravention of animal transport and welfare legislation. The welfare of animals would be improved if each VC included a certified period of validity. In future, veterinary certificates should state clearly a maximum period of validity between certification and slaughter, a maximum distance that the animal should be transported and a minimum level of comfort under which the animal must be transported. Historically, in the Republic of Ireland, there was no suitable non-transport alternative available to cattle producers wanting to salvage an otherwise healthy animal that had suffered an accident or injury resulting in acute pain. An alternative is now available, with the introduction of an on-farm emergency slaughter policy.
Improving the poultry shackle line
Authors: Lines JA , Berry P , Cook P , Schofield CP , Knowles TG
Published: May 2012

The most significant welfare problems associated with the current design of the shackle lines and water-bath stunners are the pain caused by compression of the birds’ legs in the shackles, the stress caused by being inverted and suspended by the legs, poor or inadequate stunning caused by the commercial need to minimise carcase damage, and poor water-bath entry. Research is described in which some practical solutions to these problems were investigated. The aim is to identify solutions that individually, or jointly, could be retro-fitted to existing plants, or incorporated into the design of new, small processing plants to improve poultry welfare. The development and commercial availability of such systems would enable small, local and niche market poultry processing lines to continue operating following the implementation of EC Council Regulation No 1099/2009.
Complications during shechita and halal slaughter without stunning in cattle
Authors: Gregory NG , von Wenzlawowicz M , von Holleben K , Fielding HR , Gibson TJ , Mirabito L , Kolesar R
Published: May 2012

This paper summarises the findings from five studies in eight countries on over 1,500 cattle slaughtered commercially by the halal or shechita methods without stunning. It reports the number of cuts applied to the neck, the cutting methods and the frequency of complications during the bleeding period. Complications during the bleeding period that occurred in some cattle included: (i) delay in the time to collapse, which was interpreted as late loss of consciousness; (ii) premature arrest of bleeding from the carotid arteries due to false aneurysm formation; and (iii) blood entering the respiratory tract during bleeding. These features are important as they determine or reflect the duration of consciousness following the cut and the potential for protracted suffering from wound nociception or blood irritating the respiratory tract. When cattle were not restrained following the halal cut, they took on average 20 s to collapse. Fourteen percent stood up again after an initial collapse, and 1.5% took more than 4 min before their final collapse. Eight percent took 60 s or longer to collapse, and those animals were more likely to have false aneurysms in the severed ends of the carotid arteries. False aneurysms, which were at least 3 cm in diameter, formed in the severed cardiac ends of the carotid arteries in 10% of cattle slaughtered by halal or shechita. Some false aneurysms formed in the severed ends of the carotid arteries within 7 s of the halal cut, and in 10% of the cattle bloodflow came to a halt in one of the arteries within 10 s. On average, the false aneurysms developed within 21 s. Nineteen percent of cattle slaughtered by shechita and 58% of cattle slaughtered by halal had blood lining the mucosa of the trachea. All animals had blood lining the glottis. In both situations there could be a sense of respiratory tract irritation from the blood. It is proposed that severing the carotids at the position in the neck which corresponds to C1 will reduce the frequency of false aneurysm formation and subsequent arrested bloodflow from the severed arteries, and it will deafferent the respiratory tract reducing the transmission of potentially unpleasant sensory signals associated with blood contaminating the upper and lower parts of the tract. Most cattle subjected to halal and shechita have the neck cut at a position which corresponds to C2 to C4, and changing to a cut at C1 could partly reduce the potential for suffering during slaughter without stunning.
Pain perception at slaughter
Authors: Johnson CB , Gibson TJ , Stafford KJ , Mellor DJ
Published: May 2012

Recent developments related to quantitative analysis of the electroencephalogram (EEG) have allowed the experience of pain to be assessed more directly than has hitherto been possible. Variables derived from the EEG of animals anaesthetised using our minimal anaesthesia model respond to noxious stimulation in a manner similar to those from conscious animals. This methodology has been used in a variety of applications including the evaluation of analgesic options for painful husbandry procedures and investigation of developmental aspects of the perception of pain. We have now applied the minimal anaesthesia model to the question of the slaughter of calves by ventral-neck incision. A series of studies evaluated the magnitude of EEG response to the noxious stimulus of ventral-neck incision and the physiological mechanisms that underlie this response. We also investigated the EEG effects of stunning by non-penetrating captive bolt and the ability of such stunning to ameliorate the response to ventral-neck incision. The results demonstrate clearly, for the first time, that the act of slaughter by ventral-neck incision is associated with noxious stimulation that would be expected to be painful in the period between the incision and subsequent loss of consciousness. These data provide further support for the value of stunning in preventing pain and distress in animals subjected to this procedure. We discuss the development of the minimal anaesthesia model and its adaptation for use in the investigation of slaughter by ventral-neck incision as well as considering the contributions of these studies to the ongoing development of international policy concerning the slaughter of animals.
The use of a single empirical outcome measure to assess welfare in slaughter plants: between- and within-sector comparisons of the supply base for a major retail multiple
Authors: Roberts F , Lucas A , Johnson S
Published: May 2012

The objective of the present retrospective analysis was to review between- and within-sector variations in an outcome-based measure of animal welfare throughout slaughterhouses that currently supply to Tesco Stores Ltd, UK. Non-conformances in relation to individual scheme standards were designated a specific level in terms of severity and frequency and from this a single outcome status, based on a ‘traffic-light’ system is assigned to the site (which informs both subsequent corrective action and future inspection frequency). Sector-specific, country and time differences were found and underlying contributory factors and associated commercial implications are reviewed.
4D Trajectory Estimation for Air Traffic Control Automation System Based on Hybrid System Theory
Authors: Tang Xin-Min , Han Yun-Xiang
Published: May 2012

To resolve the problem of future airspace management under great traffic flow and high density condition, 4D trajectory estimation has become one of the core technologies of the next new generation air traffic control automation system. According to the flight profile and the dynamics models of different aircraft types under different flight conditions, a hybrid system model that switches the aircraft from one flight stage to another with aircraft state changing continuously in one state is constructed. Additionally, air temperature and wind speed are used to modify aircraft true airspeed as well as ground speed, and the hybrid system evolution simulation is used to estimate aircraft 4D trajectory. The case study proves that 4D trajectory estimated through hybrid system model can image the flight dynamic states of aircraft and satisfy the needs of the planned flight altitude profile.KEY WORDSair traffic management, 4D trajectory estimation, hybrid system model, aircraft dynamic model
Spare Modules Management Optimization of Airspace Surveillance System
Authors: Propadalo Saša , Bekavac Damir , Jakšić Zoran
Published: May 2012

This paper presents an application of Poisson distribution method for managing the optimal number of spare modules of the Croatian airspace surveillance system. Out of a large number of modules and electronic parts in operation, a set of 11 critical modules are identified which have experienced failures and replacements with identical modules in three years history data. Using Poisson distribution for the failure forecasting, maintenance planner can make optimal ordering of the critical spare modules for a following period by which is possible to avoid any backordering, spare module shortage and the most important operational shutdowns. The results were the creation of the Poisson model in predicting the failure rate of radar vital modules for sizing the initial stock of spare modules to be ordered along with other electronic equipment.KEYWORDSoptimization, spare parts, Poisson distribution, forecasting, maintenance, reliability, non-repairable parts
A Model of Ship Auxiliary System for Reliable Ship Propulsion
Authors: Martinović Dragan , Tudor Mato , Bernečić Dean
Published: May 2012

The main purpose of a vessel is to transport goods and passengers at minimum cost. Out of the analysis of relevant global databases on ship machinery failures, it is obvious that the most frequent failures occur precisely on the generator-running diesel engines. Any failure in the electrical system can leave the ship without propulsion, even if the main engine is working properly. In that case, the consequences could be devastating: higher running expenses, damage to the ship, oil spill or substantial marine pollution. These are the reasons why solutions that will prevent the ship being unable to manoeuvre during her exploitation should be implemented. Therefore, it is necessary to define a propulsion restoration model which would not depend on the primary electrical energy. The paper provides a model of the marine auxiliary system for more reliable propulsion. This includes starting, reversing and stopping of the propulsion engine. The proposed solution of reliable propulsion model based on the use of a shaft generator and an excitation engine enables the restoration of propulsion following total failure of the electrical energy primary production system, and the self-propelled ship navigation. A ship is an important factor in the Technology of Transport, and the implementation of this model increases safety, reduces downtime, and significantly decreases hazards of pollution damage.KEYWORDSreliable propulsion, failure, ship auxiliary system, control, propulsion restoration
Methodology of an Aircraft Accident Response System Assessment
Authors: Županič Franc Željko , Meško Maja , Podbregar Iztok
Published: May 2012

The paper investigates the ability to learn from an aircraft accident as the opportunities for learning diminish with the decline in the accident rate. A safety compromising case is studied as the processes of aircraft accident intervention and recovery can degrade the ability of an aircraft accident investigation process to enhance aviation safety by revealing accident causation. In the case study an assessment of the Slovenian aircraft accident response system was made. For the purpose of evaluating the successfulness of aircraft accident intervention and effectiveness of recovery, a model of aircraft accident response system requirements has been developed. Based on non-conformances identified by the model of requirements, remedial measures are proposed for the enhancement of the aircraft accident response system operation. Criteria for the definition of the transition from accident intervention to recovery are derived from the assessment findings in a manner not to impede the aircraft accident investigation effectiveness and efficiency.
Ecological Impacts of Diesel Engine Emissions
Authors: Jurić Vanja , Županović Dino
Published: May 2012

This article deals with the ecological impacts of chemical substances that are found in the structure of Diesel engine exhaust gases and provides an overview of legislation that limits their maximum allowable emissions. Special consideration is given to the previously mostly neglected negative impact of particulate matter compared to the impact of carbon dioxide. Negative impact of particulates is especially noted as direct negative impact on human health whereby the expenses associated with medical treatment exceed the financial savings resulting from the usage of Diesel powered vehicles. Therefore, the paper presents the knowledge acquired through previous scientific research in the economically most developed countries, as well as the tendencies for the reduction of negative impacts of Diesel exhaust gases.