Uniform Foundation Research Articles

Dynamic stability of slightly curved tensioned pipe conveying pressurized hot two phase fluid resting on non uniform foundation

The dynamic stability of slightly curved tensioned pipes conveying pressurized two phase fluid, under thermal loadings are investigated in this paper. Furthermore, these pipes are resting on nonuniform elastic foundations. The equation of motion of the system is derived using the extended Hamilton’s principle for open dynamic systems and considering the Euler–Bernoulli theory for slender beams. The free vibration and the effects of two phase fluid flow, geometric imperfections, thermal, tension and pressure on the pipe system resting on nonuniform foundations are investigated numerically. Three different boundary conditions (BC) are considered, namely simply-simply (SS) supported, simply-clamped (SC) supported and clamped-clamped (CC) supported. The numerical method of Finite Element was used on the partial differential equation. This method is used to accurately predict steady state natural frequency responses of a dynamical system through several numerical investigations. It was found that the stability of slightly curved pipes conveying two phase flow are significantly affected by the boundary condition. It is shown that the initial curvature term increases the critical velocities for all the nine modes considered, the increase is significant in the first and second critical velocities compared to the other modes. Initial curvature effect is more pronounced in simple supported ends. Further-more the influence of the fluid velocity, temperature, pressure and axial tension is analysed; the results show that the vibration frequency decreases when the fluid velocity, temperature, and pressure increase or the axial tension decreases, and the critical fluid velocity decreases when the temperature and pressure increase or the axial tension decreases. For the pipe on nonuniform foundation, an increased stiffness leads to an increased in the first critical velocity for all the BC. However, the pattern of the increment depends on the attachment parameter, initial curvature, and the vapour quality. Some of these results are completely absent in pipes conveying single flows.

Prenatal and postnatal exposures to endocrine disrupting chemicals and timing of pubertal onset in girls and boys: a systematic review and meta-analysis.

Globally, the ages at pubertal onset for girls and boys have been decreasing during recent decades, partly attributed to excess body fat accumulation. However, a growing body of literature has recognized that endocrine disrupting chemicals (EDCs) may play an important role in this global trend, but the association has not yet been fully established. EDCs can interfere with normal hormone function and metabolism and play a role in pubertal onset. We aimed to systematically identify and evaluate the current evidence on the timing of pubertal onset in girls and boys following prenatal or postnatal exposures to xenobiotic EDCs. Following PRISMA guidelines, we performed a systematic literature search of original peer-reviewed publications in the PubMed database through a block search approach using a combination of index MeSH and free text search terms. Publications were considered if they covered biomarkers of prenatal or postnatal exposures to xenobiotic EDCs (European Commission's list of category 1 EDCs) measured in maternal or child biospecimen and pubertal onset defined by the progression of the following milestones (and assessed in terms of the following measures): menarche (age), thelarche (Tanner staging) and pubarche (Tanner staging), in girls, and genital stage (Tanner staging), testicular volume (ml) and pubarche (Tanner staging), in boys. The literature search resulted in 703 references, of which we identified 52 publications fulfilling the eligibility criteria for the qualitative trend synthesis and 23 publications for the meta-analysis. The qualitative trend synthesis provided data on 103 combinations of associations between prenatal or postnatal exposure to EDC compounds groups and puberty outcomes and the meta-analysis enabled 18 summary risk estimates of meta-associations. Statistically significant associations in the qualitative trend synthesis suggested that postnatal exposure to phthalates may be associated with earlier thelarche and later pubarche. However, we did not find consistent evidence in the meta-analysis for associations between timing of pubertal onset in girls and boys and exposures to any of the studied xenobiotic EDCs. We were not able to identify specific pre- or postnatal windows of exposure as particularly critical and susceptible for effects of EDCs. Current evidence is subject to several methodological challenges and inconsistencies and evidence on specific exposure-outcome associations remains too scarce to firmly confirm EDC exposure as a risk factor for changes in age of pubertal onset in the general child population. To create a more uniform foundation for future comparison of evidence and to strengthen pooled studies, we recommend the use of more standardized approaches in the choice of statistical analyses, with exposure transformations, and in the definitions and assessments of puberty outcomes. The impact of mixtures of EDC exposures on the association also remains unestablished and would be valuable to elucidate for prenatal and postnatal windows of exposure. Future large, longitudinal epidemiological studies are needed to clarify the overall association.

Ontologies' Closures Modeling by Formalisms of Semantic Hierarchies

Schemes are studied for modeling the complex knowledge structures as synthesized from knowledge areas ontologies elements. These structures applications relate to knowledge life cycles and knowledge flows stages within intelligent systems. The format of semantic hierarchies is proposed as unified and universal for the synthesis of these structures. This allows replacing the general case of knowledge algebraic structures by special case of semantic hierarchies. Constructing the synthesized knowledge structures is performed by special operations knowledge alge­braic structures in any knowledge representation formalisms. These operations simulate fundamental mathematical systems functional aspects. They are adapted to the knowledge formalisms attributes. Attributes are explored within different knowledge areas. They associated generally with thinking operations and mind memory structure. Datasets (operations bases) of synthesis processes operations are constructed as special classes of knowledge with a uniform structure. Ontologies for considered knowledge areas are used as source of such bases constructing. Ontologies closures are defined as sets of knowledge that may be constructed off ontologies elements by synthesis operations. They determine the ontologies expressive capabilities. The constructs and operations over ontologies, that proposed at descriptive logics, can be modelled by knowledge complete structural representations, adopted for semantic hierarchies formalisms. Such formalisms are convenient for simulating knowledge presentation and processing. They form foundation for constructing intelligent systems abstract and applied models.. The possibility is proved for trans­ferring the knowledge properties and knowledge processing schemes at semantic hierarchies to the general case of knowledge algebraic structures. The schemes for modeling the ontological constructions as semantic hierarchies are given. This proves possibility of applying such formalisms as the basis for modeling synthesis processes in ontolo­gies. Such schemes allow constructing the ontologies closures as generated by knowledge-processing operations sequences. Last fact means possibility for formalisms of semantic hierarchies to be uniform foundation of modelling the knowledge flows and knowledge transforming processes by intelligent systems.

Numerical Study of Static Instability of Pipe Conveying Incompressible Fluid under Different Boundary Conditions

In this article, the influences of uniform velocity profile, mass ratio, length and Winkler elastic foundation on the static instability of pipe conveying incompressible fluid are investigated. The Euler-Bernoulli beam theory is employed to derive partial differential equation of pipes carrying fluid. The results were carried out using ANSYS Workbench program, where the analysis is based on the numerical solution; using Finite element method to formulate both the pipe structure and fluid flow equations. The numerical approach is based on some research and analytical models. The natural frequencies of the system are attained with respect to different boundary conditions, such as pinned-pinned ends, clamped-pinned ends and clamped-clamped ends. The numerical results show satisfactory agreement with the theory of many aspects of the pipe dynamical carrying incompressible fluid were observed numerically such as, the increase in flow velocity, mass ratio and length reduced from the rigidity of the system and consequently the proper modes. Winkler elastic foundation has a stabilizing effect on the system.

Effectiveness of State Supervision and Control of Foundations' Economic Activity

The construction of supervision and control of foundations and their economic activity in Poland is fairly well developed. The main goal of this research was to ascertain whether the procedure of supervision works effectively. It was also to highlight those supervision elements and stages that do not perform their role accurately and to indicate the reasons thereof. It is important to intensify the discussion on the change of the model of founda- tion supervision into a more effective system on the one hand, and less troublesome for entrepreneurs on the other. The research of this type has never been conducted through the cross-impact analysis. Every ministry presents only the analysis in relation to the foundations subordinated to them. There is no pooled analysis of the supervision state on economic activity of foundations in Poland, and in this respect, this study is a novel scientific contribution. The conclusion drawn from it points to a necessity for simplifica- tion, standardisation (a uniform foundation activity report form is not sufficient) and the introduction of instruments to affect the current foundations’ activity.

Analysis on Calculated Length for Buckling Stability of Steel Pipe Pile Based on Energy Method

According to the Winkler assumption, the form of the pile constraint could be simplified as bottom fixing and top free. Considering the influence from resistance of soil around pile, the equations on calculated length for buckling stability of steel pipe pile when the portions along the pile length were constrained in the uniform foundation and the layered foundation were respectively derived based on energy method and variational principles. And the application of the formulas was explained through examples. The equations are successfully applied in similar projects.

A Knowledge Modeling Method for Computer Graphics Design & Production Based on Ontology

As one of the most critical stages of CG (Computer Graphics) industry, CG design & production needs the support of professional knowledge and practice experience of multidisciplinary. With the outstanding performance in knowledge sharing, integration and reuse, knowledge modeling could increase greatly the efficiency, reduce the cost and avoid repeated error in CG design & production. However, knowledge modeling of CG design & production differs greatly from those of other fields. On the one hand, it is similar to physical product design, which involves great deal of tacit knowledge such as modeling skills, reasoning knowledge and so on. On the other hand, as film, CG design & production needs a lot of unstructured description information. The heterogeneity between physical product and film makes knowledge modeling more complicated. Thus a systematic knowledge modelling method based on Ontology is proposed to aid CG design & production in this paper. CG animation knowledge is capture and organized from viewpoint of three aspects: requirements and design and production. The knowledge are categorized into static and dynamic knowledge, and Ontology is adopted to construct a hierarchic model to organize the knowledge, so as to offer a uniform communication semantic foundations for designers from different fields. Based on animation script, the CG design task model is proposed to drive the organization and management of different knowledge involved in CG design & production. Finally, we apply this method in the knowledge modeling of naked-eye animation design and production to illustrate effectiveness of this method.

Design and Field Monitoring of Piled Raft Foundations with Deformation Adjustors

AbstractThis paper presents a case study of applying a new device termed deformation adjustor in piled raft foundations to support a high-rise building. The deformation adjustors are mounted on a pile head to optimize load distribution of a piled raft foundation so that a relatively uniform foundation deformation can be achieved in complicated load, construction, and soil conditions. In this case study, the project site is located in a coastal city in China, featuring complicated subsurface soil conditions with abundant large boulders. The project was put on hold for a decade because in the complicated soil conditions the piles could not be installed to the required depths. The project resumed with introduction of deformation adjustors which helped to shift the applied loads from piles to subsoil below the raft and thus considerably reduced the pile lengths. This case study describes the preliminary design of pile-raft foundations with deformation adjustors, followed by a comprehensive monitoring program ...

Dynamics of beams on non-uniform nonlinear foundations subjected to moving loads

This paper presents a study on the dynamic response of beams on nonlinear elastic foundations, subjected to moving loads. The effects of the load’s intensity and velocity and of the foundation’s stiffness are investigated. Critical velocities are determined for beams on uniform foundations or foundations composed of two sub-domains with different values of stiffness, with or without viscous damping. In the case of non-uniform linear foundations, a very good agreement is obtained between the results of the model and available analytical solutions. The goal of this study is to generalize, for more realistic foundation behaviors, the analyses obtained by other authors.

Full 3D homogenization approach to investigate the behavior of masonry arch bridges: The Venice trans-lagoon railway bridge

Some different procedures for the evaluation of the non-linear behavior of masonry arch bridges are here proposed. In particular, the Venice trans-lagoon masonry arch bridge is numerically analyzed by means of several 3D FE numerical strategies. The three dimensional behavior of the structure when subjected to train loads and pile foundation settlement is investigated. Focus is also posed to the stabilizing role played by the backfill.Both a non-commercial code and a standard commercial FE software are utilized. The non-commercial code properly takes into account for the orthotropic behavior of the barrel vaults and the stone arches, and allows performing non-linear static and limit analyses on complex 3D structures. Within the non-commercial FE approach, each material of the bridge (barrel vault, external stone arches, spandrels, piers, backfill) is suitably modeled using rigid parallelepiped elements and quadrilateral interfaces exhibiting an orthotropic constitutive law with either softening or rigid-plastic behavior in the non-linear and limit analysis version respectively. In both FE codes, mechanical properties of each material of the bridge (barrel vault, external stone arches, spandrels, piers, backfill) are modeled starting from suitable homogenization procedures in the elastic range (commercial software) and also beyond the linear limit (non-commercial FEM).The bridge is studied under service loads and up to failure for the passage of a standard train on either a single or both tracks. In the analyses, the stabilizing role played by the backfill, the strength increase obtained with stiff lateral stone arches on the barrel vault and the 3D effects induced by both load configurations are discussed. Results obtained with the incremental non-linear procedures are always compared with limit analysis predictions of collapse loads and failure mechanisms.Finally a uniform foundation settlement of one of the piles is simulated.

ANALYSIS OF HIGH-SPEED RAIL ACCOUNTING FOR JUMPING WHEEL PHENOMENON

In this paper, a computational study using the moving element method (MEM) was carried out to investigate the dynamic response of a high-speed train–track system. Results obtained using Hertz contact model and linearized Hertz contact model are compared and discussed. The dynamic responses of a train travelling across a uniform foundation and a transition region are also investigated. Parametric study is performed to understand the effect of various factors on the occurrence and patterns of the jumping wheel phenomenon such as the variation of foundation stiffness, travelling speed of the train and the severity of railhead roughness.

On educating the medical writer

Most medical writers received their education on the job rather than through formal education. These writers may have gaps in knowledge when compared with lists of competencies published by professional organisations in the clinical research and medical writing fields. Formal education from an accredited programme gives a more uniform foundation of knowledge than experience alone or experience combined with short-term training. This article, based on the observations of a regulatory medical writer turned academic programme director, addresses some of the differences between education and training, educational approaches and delivery methods, and potential effects on employment prospects.

Analysis of Nonlinear Dynamic for Piles under Earthquake Loading

The nonlinear dynamic response of piles in uniform foundation under earthquake loading is investigated. Based on the established nonlinear equations of motion of piles under earthquake loading, the approximate solution of the pile for the case of the resonance is obtained by the method of multiple scales. The effects of major parameters on seismic force are studied, such as, frequency ratio, shear wave velocity, soil thickness. And the effects of the major parameters on the frequency response curves of the pile in single layer soil are studied. Comparing with the non-resonant response of the pile, the effect of the resonance on the actual dynamic response is analyzed. The results shows that shear wave velocity and soil thickness have significant effect on the seismic force in soft clay, which have little effect on the seismic force in the other soil layers; soil thickness has the most important influence on the nonlinear dynamic response of pile and it is followed by the earthquake coefficient, the shear wave velocity in the effects.

Toward a Theory of Planarity: Hanani-Tutte and Planarity Variants

We study Hanani-Tutte style theorems for various notions of planarity, including partially embedded planarity, and simultaneous planarity. This approach brings together the combinatorial, computational and algebraic aspects of planarity notions and may serve as a uniform foundation for planarity, as suggested in the writings of Tutte and Wu.

FEM Formulation for Dynamic Instability of Fluid-Conveying Pipe on Nonuniform Elastic Foundation

In this study, we investigate the effect of a nonuniform Winkler-type elastic foundation on the stability of pipes conveying fluid fixed at the upstream end only. A stability analysis of transverse motion aims at determining the flutter velocity as a function of the governing control parameters such as fluid mass over the pipe mass ratio, or foundation stiffness. The global stability of the system is analyzed applying an ad-hoc developed finite-element formulation that leads to a discrete state-space equation of motion. It is shown that for a uniform foundation, an increased stiffness of the Winkler coefficient leads to an increased critical flow speed for any value fluid/pipe mass ratio, while in the case of a nonuniform elastic foundation, the system may present higher or lower critical flow speed depending on the fluid/pipe mass ratio. Special attention is paid to the “𝓈” type behavior of the instability curves, as reported in numerous papers.

Experimental Study on Optimization Design of Variable Diameter Pile-Raft Foundation

Test model who’s scale is 1:10 was established. According to the actual engineering, through the model test, the laws about the settlement of the pile-raft foundation, vertical and horizontal settlement of soil, pile force, soil force and pile-soil stress ratio were studied under natural foundation, uniform and variable diameter pile-raft foundation. It can provide theoretical basis for Future research the pile raft foundation.

On Security Development Lifecycle: Conceptual Description of Vulnerabilities, Risks, and Threats

Security Development Lifecycle (SDL) is a software assurance methodology that aims at assisting software developers in improving the security of software production. Typically SDL is described in terms of phases that include requirements and design phases. The Requirements phase embraces consideration of security and privacy at a foundational level. This consideration comprises several activities in security requirements, security risk assessment, and threat modeling. The problem is that basic notions at this level are categorized and conceptualized as arbitrary collections of assets, operations, techniques, etc. with no systematic connection between them. This paper is part of an effort that aims at building a uniform foundation for notions in SDL. It focuses on requirements phase analysis, where we analyze conceptual aspects that involve the notions of threats, risks, and vulnerabilities. We work on two aspects: 1. The notions of threats, risks, and vulnerabilities are conceptualized utilizing a new approach based on the notion of flow. 2. The flow-based methodology is presented as an alternative description to using data flow diagrams as a first step in modeling threats. In both cases the analysis is performed utilizing sample cases.

Modeling surgical processes: A four-level translational approach

The precise and formal specification of surgical interventions is a necessary requirement for many applications in surgery, including teaching and learning, quality assessment and evaluation, and computer-assisted surgery. Currently, surgical processes are modeled by following various approaches. This diversity lacks a commonly agreed-upon conceptual foundation and thus impedes the comparability, the interoperability, and the uniform interpretation of process data. However, it would be beneficial if scientific models, in the same context, shared a coherent conceptual and formal mathematical basis. Such a uniform foundation would simplify the acquisition and exchange of data, the transition and interpretation of study results, and the transfer and adaptation of methods and tools. Therefore, we propose a generic, formal framework for specifying surgical processes, which is presented together with its design methodology. The methodology follows a four-level translational approach and comprises an ontological foundation for the formal level that orients itself by linguistic theories. A unifying framework for modeling surgical processes that is ontologically founded and formally and mathematically precise was developed. The expressive power and the unifying capacity of the presented framework are demonstrated by applying it to four contemporary approaches for surgical process modeling by using the common underlying formalization. The presented four-level approach allows for capturing the knowledge of the surgical intervention formally. Natural language terms are consistently translated to an implementation level to support research fields where users express their expert knowledge about processes in natural language, but, in contrast to this, statistical analysis or data mining need to be performed based on mathematically formalized data sets. The availability of such a translational approach is a valuable extension for research regarding the operating room of the future.

Clinician's Commentary

Cardiopulmonary physiotherapy (CPT) encompasses a wide variety of treatment techniques that address the physiologic and functional impairments to effective ventilation, oxygen transport, and oxygen utilization. These treatment techniques may include breathing exercises, manual secretion-clearance techniques, positioning, mobility, and activity. Physiotherapists ensure that the use of rehabilitation resources has purpose and is goal oriented. Most importantly, the discontinuation of physiotherapy services should be based on the achievement of treatment goals and the assurance that the patient is not likely to deteriorate when the cessation of physiotherapy services. The Paediatric Cardiopulmonary Physiotherapy Discharge Tool described in this issue of Physiotherapy Canada addresses the goal of facilitating the optimal timing of discharge from hospital for paediatric CPT patients.1 Although the principles by which physiotherapists develop clinical impressions are based on a uniform foundation of knowledge, practice settings and resource availability can be diverse drivers of physiotherapy services. In one hospital, physiotherapy resources may be limited, while in another they are abundant. In addition, the complexity of cardiac, thoracic, and upper-abdominal surgeries may also affect the length of stay, thus causing wait lists to grow. As a result, the strains on a variety of hospital resources may affect the discharge of a post-surgical patient from an acute-care hospital. The Delphi panel approach used by Ellerton et al. to determine the content of the discharge tool takes into consideration the perspectives of multiple experts with diverse experiences. This process enables the development of a consensus identifying the factors that may guide the decision to discharge from postoperative CPT in a wide variety of paediatric clinical settings. Ellerton et al. demonstrate that the criterion items included in their paediatric discharge tool are similar to those included in the adult-focused Postoperative Physiotherapy Discharge Scoring Tool, or POP-DST2 (mobility, breath sounds, secretion clearance, SpO2, respiratory rate). However, clear distinctions in the paediatric population are identified in their study. The inclusion of discharge planning and the evaluation of respiratory distress instead of respiratory rate alone were found to be important assessment criteria for paediatric physiotherapists practising CPT. Discharge planning illustrates one of the unique differences between adult and paediatric care: children's inherent dependence on a support system, whether it be family or community-based care. The discharge-planning criteria identified by the Delphi panel highlight this area of attention, ensuring that the physiotherapist assesses whether a paediatric patient has no requirement for CPT support after discharge from hospital, requirement for CPT support after discharge from family independently, or requirement for further CPT resources and support after discharge beyond what can be managed by family. Furthermore, by including an assessment of discharge-planning requirements, the physiotherapist can ensure that discontinuation of CPT in a paediatric acute-care setting is safe and that the patient will continue to receive necessary care. Assessment of these requirements will also ensure that length of stay and use of acute-care resources are minimized, thereby minimizing health care costs. The inclusion of signs of respiratory distress is another distinction in the management of paediatric as opposed to adult patients. Assessment of respiratory rate alone is not sufficient to indicate whether or not a child is in distress; there is physiological variability in respiratory rate between children of different age groups, as well as variability within the same age group due to factors such as anxiety. Paediatric physiotherapists use a wide variety of signs of respiratory distress to understand a patient's work of breathing; in particular, smaller children will demonstrate intercostal indrawing, nasal flaring, or tracheal tugging as a sign of respiratory distress. Therefore, this discharge tool effectively cues the PT to assess the presence of respiratory distress from a wide range of manifestations.1 Ellerton et al. have effectively compiled a group of fundamental factors to be used when assessing a paediatric patient's readiness for discharge from CPT. The development of a scoring system and an assessment of the psychometric properties of the Paediatric Cardiopulmonary Physiotherapy Discharge Tool will ultimately provide a valuable resource to guide clinical decisions. For the novice physiotherapist, in particular, this tool could help to ensure a high standard of care that optimizes resource utilization.

Approximation Spaces in Rough–Granular Computing

We discuss some generalizations of the approximation space definition introduced in 1994 [24, 25]. These generalizations are motivated by real-life applications. Rough set based strategies for extension of such generalized approximation spaces from samples of objects onto their extensions are discussed. This enables us to present the uniform foundations for inducing approximations of different kinds of granules such as concepts, classifications, or functions. In particular, we emphasize the fundamental role of approximation spaces for inducing diverse kinds of classifiers used in machine learning or data mining.