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Internal Pressure (internal + pressure)
Selected AbstractsBINOL-3,3,-Triflone N,N -Dimethyl Phosphoramidites: Through-Space 19F,31P Spin,Spin Coupling with a Remarkable Dependency on Temperature and Solvent Internal PressureCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2008Matthias Kruck Abstract A combined computational and experimental study of the effects of solvent, temperature and stereochemistry on the magnitude of the through-space spin,spin coupling between 31P and 19F nuclei which are six-bonds apart is described. The reaction of 3-trifluoromethylsulfonyl-2,,2-dihydroxy-1,1,-binaphthalene (3-SO2CF3 -BINOL) with hexamethylphosphorous triamide (P(NMe2)3) generates a pair of N,N -dimethylphosphoramidites which are diastereomeric due to their differing relative configurations at the stereogenic phosphorous centre and the axially chiral (atropisomeric) BINOL unit. Through-space NMR coupling of the 31P and 19F nuclei of the phosphoramidite and sulfone is detected in one diastereomer only. In the analogous N,N -dimethylphosphoramidite generated from 3,3,-(SO2CF3)2 -BINOL only one of the diastereotopic trifluoromethylsulfone moieties couples with the 31P of the phosphoramidite. In both cases, the magnitude of the coupling is strongly modulated (up to 400,%) by solvent and temperature. A detailed DFT analysis of the response of the coupling to the orientation of the CF3 moiety with respect to the P-lone pair facilitates a confident assignment of the stereochemical identity of the pair of diastereomers. The analysis shows that the intriguing effects of environment on the magnitude of the coupling can be rationalised by a complex interplay of solvent internal pressure, molecular volume and thermal access to a wider conformational space. These phenomena suggest the possibility for the design of sensitive molecular probes for local environment that can be addressed via through-space NMR coupling. [source] On introducing approximate solution methods in theory of elasticityCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2006Autar Kaw Abstract This work presents how approximate solution methods were introduced in a graduate level course of Theory of Elasticity. The three methods introduced are the finite difference method, the finite element method, and the boundary element method. All methods are exemplified by the problem of a thick-walled cylinder subject to internal pressure with an axisymmetric response. Choosing a single problem to introduce the three methods demonstrates accuracy and efficacy of each method. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 120,134, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20070 [source] Stress-life fatigue assessment of pipelines with plain dentsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 12 2009S. B. CUNHA ABSTRACT This paper presents a new algorithm for assessing the fatigue life of dented pipelines. The proposed methodology was conceived according to the current stress-life fatigue theory and design practice: it employs S,N curves inferred from tensile test material properties and uses well established methodologies to deal with the stress concentration, the mean stress and the multi-axial stress state that characterizes a dented pipe. Finite element analyses are carried out to model the denting process and to determine the stress concentration factors of several pipe-dent geometries. Using dimensional analysis over the numerical results, a non-dimensional number to characterize the pipe-dent geometry is determined and linear interpolation expressions for the stress concentration factors of dented pipelines are developed. Fatigue tests are conducted with the application of cyclic internal pressure on small-scale dented steel pipe models. In view of the fatigue test results, the more appropriate S,N curve and mean stress criteria are selected. [source] The role of friction and secondary flaws on deflection and re-initiation of hydraulic fractures at orthogonal pre-existing fracturesGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2006Xi Zhang SUMMARY In this study, we explore the nature of plane-strain hydraulic fracture growth in the presence of pre-existing fractures such as joints without or with secondary flaws. The 2-D plane-strain fracture studied can be taken as a cross-section through the short dimensions of an elongated 3-D fracture or as an approximate representation of the leading edge of a 3-D fracture where the edge curvature is negligible. The fluid-driven fracture intersects a pre-existing fracture to which it is initially perpendicular and is assumed not to immediately cross, but is rather deflected into the pre-existing fracture. The intersection results in branching of the fracture and associated fluid flow into the pre-existing fracture. Further growth results in opening and frictional sliding along the pre-existing fracture. Fracture propagation in an impermeable homogeneous elastic medium and fluid invasion into a pre-existing fracture are both driven by an incompressible, Newtonian fluid injected at a constant rate. The frictional stress on the surfaces of pre-existing fractures is assumed to obey the Coulomb law. The governing equations for quasi-static fluid-driven fracture growth are given and a scaling is introduced to help identify important parameters. The displacement discontinuity method and the finite difference method are employed to deal with this coupling mechanism of rock fracture and fluid flow. In order to account for fluid lag, a method for separately tracking the crack tip and the fluid front is included in the numerical model. Numerical results are obtained for internal pressure, frictional contact stresses, opening and shear displacements, and fluid lag size, as well as for fracture re-initiation from secondary flaws. After fracture intersection, the hydraulic fracture growth mode changes from tensile to shearing. This contributes to increased injection pressure and to a reduction in fracture width. In the presence of pre-existing fractures, the fluid-driven cracks can be arrested or retarded in growth rate as a result of diversion of fluid flow into and frictional sliding along the pre-existing fractures. Frictional behaviour significantly affects the ability of the fluid to enter or penetrate the pre-existing fracture only for those situations where the fluid front is within a certain distance from the intersecting point. Importantly, fluid penetration requires higher injection pressure for frictionally weak pre-existing fractures. Fracture re-initiation from secondary flaws can reduce the injection pressure, but re-initiation is suppressed by large sliding on pre-existing fractures that are frictionally weak. [source] Pressures generated in vitro during Stabident intraosseous injectionsINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2005J. M. Whitworth Abstract Aim, To test the hypothesis that the Stabident intraosseous injection is a potentially high-pressure technique, which carries serious risks of anaesthetic cartridge failure. Methodology, A standard Astra dental syringe was modified to measure the internal pressure of local anaesthetic cartridges during injection. Intra-cartridge pressures were measured at 1 s intervals during slow (approximately 15 s) and rapid (<10 s) injections of 2% Xylocaine with 1 : 80 000 adrenaline (0.25 cartridge volumes) into air (no tissue resistance), or into freshly prepared Stabident perforation sites in the anterior mandible of freshly culled young and old sheep (against tissue resistance). Each injection was repeated 10 times over 3 days. Absolute maximum pressures generated by each category of injection, mean pressures at 1 s intervals in each series of injections, and standard deviations were calculated. Curves of mean maximum intra-cartridge pressure development with time were plotted for slow and rapid injections, and one-way anova (P < 0.05) conducted to determine significant differences between categories of injection. Results, Pressures created when injecting into air were less than those needed to inject into tissue (P < 0.001). Fast injection produced greater intra-cartridge pressures than slow delivery (P < 0.05). Injection pressures rose more quickly and to higher levels in small, young sheep mandibles than in larger, old sheep mandibles. The absolute maximum intra-cartridge pressure developed during the study was 3.31 MPa which is less than that needed to fracture glass cartridges. Conclusions, Stabident intraosseous injection conducted in accordance with the manufacturer's instructions does not present a serious risk of dangerous pressure build-up in local anaesthetic cartridges. [source] Numerical modelling of compensation grouting above shallow tunnelsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 5 2005C. Wisser Abstract This paper describes the development of a numerical model for compensation grouting which is a useful technique for the protection of surface structures from the potentially damaging movements arising from tunnel construction. Pipes are inserted into the ground between the tunnel and the overlaying structure from an access shaft. Buildings on the surface are instrumented and movements are carefully monitored. Once the deformations exceed a certain Trigger Level, grout is injected into the ground to prevent damage. In the finite element model described here, compensation grouting is modelled by applying an internal pressure to zero-thickness interface elements embedded in the mesh. An ,observational algorithm' is used, where the deformations of the surface are monitored and used to control the injection process. Example analyses of compensation grouting are given for three-dimensional tunnel construction underneath a greenfield site. Different strategies are used to control the injection process and their effectiveness in preventing surface movement is assessed. The numerical model is shown to replicate general behaviour expected in the field and is capable of modelling the control of ground surface movements at a greenfield site. Copyright © 2005 John Wiley & Sons, Ltd. [source] Meshfree simulation of failure modes in thin cylinders subjected to combined loads of internal pressure and localized heatINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2008Dong Qian Abstract This paper focuses on the non-linear responses in thin cylindrical structures subjected to combined mechanical and thermal loads. The coupling effects of mechanical deformation and temperature in the material are considered through the development of a thermo-elasto-viscoplastic constitutive model at finite strain. A meshfree Galerkin approach is used to discretize the weak forms of the energy and momentum equations. Due to the different time scales involved in thermal conduction and failure development, an explicit,implicit time integration scheme is developed to link the time scale differences between the two key mechanisms. We apply the developed approach to the analysis of the failure of cylindrical shell subjected to both heat sources and internal pressure. The numerical results show four different failure modes: dynamic fragmentation, single crack with branch, thermally induced cracks and cracks due to the combined effects of pressure and temperature. These results illustrate the important roles of thermal and mechanical loads with different time scales. Copyright © 2008 John Wiley & Sons, Ltd. [source] RETORTABILITY of THIN-WALLED ALUMINUM CONTAINERS PRESSURIZED WITH ADDED LIQUID NITROGEN (LN2)JOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2003G.B. AWUAH ABSTRACT Studies were conducted to investigate the effect of initial container pressure on heat penetration parameters using flexible aluminum containers. A pilot scale liquid nitrogen dispenser, regulated to discharge a fine stream of liquid nitrogen (LN2), provided approximately 10 to 15 psi pressure within the container prior to end-over-end processing in a computer-controlled retort using water immersion with 32 psi over pressure. Thermal process parameters including the heating rate index (fh), lag factor (jh), the cumulative lethality (Fo), cook-value (Co) and the overall heat transfer coefficient (Uo) were examined in relation to retort temperature (241,261F), rpm (0,15 rpm) and product initial temperature (54,121F) using 5% w/w bentonite suspension with or without liquid nitrogen. Generally, containers with added liquid nitrogen had no impact on evaluated data compared to their counterparts without LN2 under similar experimental conditions. Estimated overall heat transfer coefficient (Uo) compared favorably with published data, while the Co/Fo ratio decreased with increasing temperatures as expected. Product cold spot location migrated in either upward or downward direction depending on the mode of heat transfer. Although added LN2 generally had no limiting effect on both heat transfer and heat penetration data, processing aluminum containers with high initial pressure at high retort temperatures could create excessively high internal pressure that could compromise container seam integrity. [source] Functional morphology of the sonic apparatus in the fawn cusk-eel Lepophidium profundorum (Gill, 1863)JOURNAL OF MORPHOLOGY, Issue 11 2007Michael L. Fine Abstract Recent reports of high frequency sound production by cusk-eels cannot be explained adequately by known mechanisms, i.e., a forced response driven by fast sonic muscles on the swimbladder. Time to complete a contraction-relaxation cycle places a ceiling on frequency and is unlikely to explain sounds with dominant frequencies above 1 kHz. We investigated sonic morphology in the fawn cusk-eel Lepophidium profundorum to determine morphology potentially associated with high frequency sound production and quantified development and sexual dimorphism of sonic structures. Unlike other sonic systems in fishes in which muscle relaxation is caused by internal pressure or swimbladder elasticity, this system utilizes antagonistic pairs of muscles: ventral and intermediate muscles pull the winglike process and swimbladder forward and pivot the neural arch (neural rocker) above the first vertebra backward. This action stretches a fenestra in the swimbladder wall and imparts strain energy to epineural ribs, tendons and ligaments connected to the anterior swimbladder. Relatively short antagonistic dorsal and dorsomedial muscles pull on the neural rocker, releasing strain energy, and use a lever advantage to restore the winglike process and swimbladder to their resting position. Sonic components grow isometrically and are typically larger in males although the tiny intermediate muscles are larger in females. Although external morphology is relatively conservative in ophidiids, sonic morphology is extremely variable within the family. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Rate enhancement of Diels,Alder reactions in aqueous solutionsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 2 2004Giuseppe Graziano Abstract It is shown that the concept of internal pressure cannot be used to explain the strong rate enhancement of Diels,Alder reactions when carried out in water with respect to common organic solvents. Copyright © 2004 John Wiley & Sons, Ltd. [source] Atmospheric Pressure Synthesis of Heavy Rare Earth Sesquioxides Nanoparticles of the Uncommon Monoclinic PhaseJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007Bing Guo We report, for the first time, the atmospheric pressure synthesis of nonagglomerated nanoparticles (20,60 nm in diameter) of the uncommon monoclinic phase of some heavy rare earth sesquioxides RE2O3 (RE=Dy, Ho, Er, Tm, and Yb). The RE2O3 nanoparticles, prepared by a flame synthesis process, were characterized by X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. Monoclinic nanoparticles were formed when the flame temperature was sufficiently high; lower temperatures led to the formation of the normal cubic (C-type) phase. We explain the formation of the uncommon monoclinic phase on the basis of pressure,temperature phase equilibria, and the extra internal pressure induced by surface curvature of the nanoparticles. [source] Residual stress analysis of an autofrettaged compound cylinder under machining processMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 3 2009E.-Y. Lee Autofrettage; Schrumpfpassung; Verbundzylinder; Bearbeitungsprozess Abstract The autofrettage process is used to manufacture pressure vessels and cylinders that can withstand high internal pressure. A multi-layered cylinder was assembled by a shrink fit. Autofrettaged compound cylinder can resist higher internal pressure than a thick cylinder having the same dimension and extend its life time. Inner and outer surfaces of the autofrettaged compound cylinder have to be manufactured into exact dimensions. The distribution of residual stress can change after the machining process. The machining procedure of inner and outer surfaces also affects the distribution of residual stress as a function of the machining procedure. In this study, the distribution of residual stresses of an autofrettaged compound cylinder as machining procedure was investigated using analytical and numerical analyses. [source] Lebensdauerabschätzung an Kunststoffrohren mittels Zeitstand-InnendruckversuchMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 5 2007C. Berger lifetime prediction; plastic pipes; internal pressure creep test Abstract Die Lebensdauervorhersage an Kunststoffrohren basiert nach dem aktuellen Stand des technischen Regelwerkes hauptsächlich auf dem Zeitstand-Innendruckversuch. In diesem Versuch werden die Rohre bei definiertem Innendruck und erhöhten Temperaturen akzeleriert geprüft, und aufgrund des geltenden Arrheniusgesetzes erfolgt daraufhin eine Lebensdauerextrapolation der Messwerte. Lifetime Prediction of Plastic Pipes by means of Internal Pressure Creep Test The Lifetime Prediction of plastic pipes is based, according to the current set of relevant technical regulations, mainly on the Internal Creep Rupture Test. In this examination, the test for the pipes performed in an accelerated mode with a defined internal pressure and at increased temperatures. In compliance with the applicable Arrhenius rate law, an extrapolation of the measured values then takes place. [source] Triggered star formation in bright-rimmed clouds: the Eagle nebula revisitedMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2006J. Miao ABSTRACT A three-dimensional smoothed particle hydrodynamics model has been extended to study the radiation-driven implosion effect of massive stars on the dynamical evolution of surrounding molecular clouds. The new elements in the upgraded code are the inclusion of Lyman continuum in the incident radiation flux and the treatment of hydrogen ionization process; the introduction of ionization heating and recombination cooling effects; and the addition of a proper description of the magnetic and turbulent pressures to the internal pressure of the molecular cloud. This extended code not only provides a realistic model to trace the dynamical evolution of a molecular cloud, but also can be used to model the kinematics of the ionization and shock fronts and the photoevaporating gas surrounding the molecular cloud, which the previous code is unable to handle. The application of this newly developed model to the structure of the middle Eagle nebula finger suggests that the shock induced by the ionizing radiation at the front side of the head precedes an ionization front moving towards the centre of the core, and that the core at the fingertip is at a transition stage evolving toward a state of induced star formation. The dynamical evolution of the velocity field of the simulated cloud structure is discussed to illustrate the role of the self-gravity and the different cloud morphologies which appear at different stages in the evolutionary process of the cloud. The motion of the ionization front and the evaporating gas are also investigated. The modelled gas evaporation rate is consistent with that of other current models and the density, temperature and chemical profiles are in agreement with the observed values. The relative lifetimes of different simulated cloud morphologies suggest a possible answer to the question of why more bright-rimmed clouds are observed to possess a flat-core than an elongated-core morphology. [source] Influence of PET bottle weight, closure performance and filling Technique on the oxygen content of soya cooking oilPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2001Léa Mariza de Oliveira Abstract The use of PET bottles for edible oil in Brazil is increasing but there is a trend to reduce bottle weight for economic reasons, which decreases the oxygen barrier of the package. The barrier performance of a 20,g PET bottle for 900,ml soya oil, submitted to gas flushing with gaseous N2 and pressurization with liquid N2, was compared with a 27,g PET conventional bottle. During 8 months storage at 25°C the internal pressure, dissolved oxygen and oxygen in the headspace were evaluated and did not change significantly. Liquid N2 pressurization did not improve the efficiency of reducing O2 in the headspace compared to N2 gas flushing. Copyright © 2001 John Wiley & Sons, Ltd. [source] Fracture prediction in tough polyethylene pipes using measured craze strengthPOLYMER ENGINEERING & SCIENCE, Issue 5 2008P. Davis In this study, an empirical model is developed that predicts the time to failure for PE pipes under combined pressure and deflection loads. The time-dependent craze strength of different PE materials is measured using the circumferentially deep-notched tensile (CDNT) test. In agreement with previous research, results indicate that bimodal materials with comonomer side-chain densities biased toward high-molecular-weight PE molecules exhibit significantly higher long-term craze strengths. A comparison of currently available PE materials with CDNT samples taken from a PE pipe that failed by slow crack growth in service clearly indicates the superior performance of new-generation materials. Using measured craze strength data from the CDNT test, a simplified model for predicting failure in buried PE pipes is developed. Extending previous research, the reference stress concept is used to calculate an equivalent craze stress for a pipe subjected to combined internal pressure and deflection loads. Good agreement is obtained between the model predictions and observed failure times in an experimental test-bed study of pipes under in-service loading conditions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy: Sphalerite as an ExampleACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2009Yuping YANG Abstract: Raman frequency of some materials, including minerals, molecules and ions, shifts systematically with changing pressure and temperature. This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell (HDAC). Since the system of fluid inclusion is similar to that of HDAC, it can also be used to determine the internal pressure of fluid inclusions. Sphalerite is a common daughter mineral. In this study, the frequency shift of the 350 cm,1 peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC. The global slope of the isotherms (,V350/,p)T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed. The correlation between the frequency shift of the 350 cm,1 peak of sphalerite and pressure and temperature is constrained as P=208.33(,Vp)350+3.13T,943.75. This relationship may be used to estimate the internal pressure of the sphalerite-bearing fluid inclusions. [source] BINOL-3,3,-Triflone N,N -Dimethyl Phosphoramidites: Through-Space 19F,31P Spin,Spin Coupling with a Remarkable Dependency on Temperature and Solvent Internal PressureCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2008Matthias Kruck Abstract A combined computational and experimental study of the effects of solvent, temperature and stereochemistry on the magnitude of the through-space spin,spin coupling between 31P and 19F nuclei which are six-bonds apart is described. The reaction of 3-trifluoromethylsulfonyl-2,,2-dihydroxy-1,1,-binaphthalene (3-SO2CF3 -BINOL) with hexamethylphosphorous triamide (P(NMe2)3) generates a pair of N,N -dimethylphosphoramidites which are diastereomeric due to their differing relative configurations at the stereogenic phosphorous centre and the axially chiral (atropisomeric) BINOL unit. Through-space NMR coupling of the 31P and 19F nuclei of the phosphoramidite and sulfone is detected in one diastereomer only. In the analogous N,N -dimethylphosphoramidite generated from 3,3,-(SO2CF3)2 -BINOL only one of the diastereotopic trifluoromethylsulfone moieties couples with the 31P of the phosphoramidite. In both cases, the magnitude of the coupling is strongly modulated (up to 400,%) by solvent and temperature. A detailed DFT analysis of the response of the coupling to the orientation of the CF3 moiety with respect to the P-lone pair facilitates a confident assignment of the stereochemical identity of the pair of diastereomers. The analysis shows that the intriguing effects of environment on the magnitude of the coupling can be rationalised by a complex interplay of solvent internal pressure, molecular volume and thermal access to a wider conformational space. These phenomena suggest the possibility for the design of sensitive molecular probes for local environment that can be addressed via through-space NMR coupling. [source] Path-dependent climate policy: the history and future of emissions trading in EuropeENVIRONMENTAL POLICY AND GOVERNANCE, Issue 5 2004Edwin Woerdman At the end of the 1990s, the EU was still sceptical towards emissions trading, but in 2003 it adopted a directive that enables such trading in the EU from 2005 onwards. Instead of presenting ad hoc explanations, we develop and apply the path dependence approach to clarify this remarkable attitude change. Sunk costs, switching costs and learning explain why politicians were initially tempted to add credit trading to existing, sub-optimal policy. Permit trading, however, is more efficient and effective. An institutional lock-in was bound to occur, but attitudes changed as a result of internal pressures, such as the pioneering role of the European Commission, and external ,shocks', such as the withdrawal of the US from the Kyoto Protocol. A full-scale institutional break-out towards efficiency is not guaranteed, though, because elements of credit trading can still enter the permit trading directive. The risk is that these elements become locked in, from which it may be difficult to escape. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment. [source] Numerical simulation of viscous flow interaction with an elastic membraneINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2008Lisa A. Matthews Abstract A numerical fluid,structure interaction model is developed for the analysis of viscous flow over elastic membrane structures. The Navier,Stokes equations are discretized on a moving body-fitted unstructured triangular grid using the finite volume method, taking into account grid non-orthogonality, and implementing the SIMPLE algorithm for pressure solution, power law implicit differencing and Rhie,Chow explicit mass flux interpolations. The membrane is discretized as a set of links that coincide with a subset of the fluid mesh edges. A new model is introduced to distribute local and global elastic effects to aid stability of the structure model and damping effects are also included. A pseudo-structural approach using a balance of mesh edge spring tensions and cell internal pressures controls the motion of fluid mesh nodes based on the displacements of the membrane. Following initial validation, the model is applied to the case of a two-dimensional membrane pinned at both ends at an angle of attack of 4° to the oncoming flow, at a Reynolds number based on the chord length of 4 × 103. A series of tests on membranes of different elastic stiffness investigates their unsteady movements over time. The membranes of higher elastic stiffness adopt a stable equilibrium shape, while the membrane of lowest elastic stiffness demonstrates unstable interactions between its inflated shape and the resulting unsteady wake. These unstable effects are shown to be significantly magnified by the flexible nature of the membrane compared with a rigid surface of the same average shape. Copyright © 2007 John Wiley & Sons, Ltd. [source] The successful management of organisational change in tourism SMEs: initial findings in UK visitor attractionsINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 4 2008Rune Todnem By Abstract Organisational change management theory for small and medium-sized enterprises (SMEs) within the tourism industry is an under-researched field. Changing political, economic, social and technological factors can leave unprepared SMEs exposed to external as well as internal pressures, which can lead to underperformance, or in worst case scenario, business failure. This paper, reporting on the findings of exploratory research of nine UK-based visitor attractions, all qualifying as SMEs, suggests that the successful management of change is crucial for SMEs' survival and success. The findings argue that the current approach taken to organisational change management within the industry is bumpy incremental, bumpy continuous and planned. Hence, the paper provides a framework for managing organisational change based on eight critical success factors identified by the study: adaptability and flexibility, commitment and support, communication and co-operation, continuous learning and improvement, formal strategies, motivation and reward, pragmatism, and the right people. Copyright © 2008 John Wiley & Sons, Ltd. [source] Local land use strategies in a globalizing world,managing social and environmental dynamicsLAND DEGRADATION AND DEVELOPMENT, Issue 2 2006R. L. Wadley Abstract This special issue deals with local rural people's economic, social and cultural responses to external and internal pressures generated by processes of global and regional change. The contributions deal with issues of resource-base degradation and stable land management, with special emphases on market integration and increased vulnerability of natural resources and local livelihoods in Lao DPR; land-use change in a Malaysian swidden system under varied patterns of migration and off-farm labour; occupational multiplicity and agricultural specialization in the Philippines; land degradation and environmental perceptions in peri-urban Nigeria; food security, gendered labour and shifting cultural-economic values in Uganda; and the rehabilitation of environment and social institutions through neo-localism in Thailand. All of the articles were originally presented at an International Conference in Copenhagen, Denmark in 2003, under the auspices of the Danish University Consortium on Environment and Development,Sustainable Land Use and Natural Resource Management (DUCED SLUSE). Copyright © 2006 John Wiley & Sons, Ltd. [source] The environments of FRII radio sourcesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2000M. J. Hardcastle Using ROSAT observations, we estimate gas pressures in the X-ray-emitting medium surrounding 63 FRII radio galaxies and quasars. We compare these pressures with the internal pressures of the radio-emitting plasma estimated by assuming minimum energy or equipartition. In the majority of cases (including 12/13 sources with modelled, spatially resolved X-ray emission) radio sources appear to be underpressured with respect to the external medium, suggesting that simple minimum-energy arguments underestimate the internal energy density of the sources. We discuss possible departures from the minimum-energy condition and the consequences of our result for models of the dynamics of radio galaxies, in particular self-similar models. [source] Devolution and outsourcing of municipal services in Kampala city, Uganda: an early assessment,PUBLIC ADMINISTRATION & DEVELOPMENT, Issue 5 2003Frederick Golooba-Mutebi The late 1980s saw the beginning of wide-ranging economic and political reforms in Africa, prompted by both external and internal pressures. Demands for political reform pushed for democratisation, including decentralisation of power and resources to lower levels of government. Alongside pressures for democratisation were those for economic liberalisation, including the rolling back of the state characterised by, among other things, reducing its role in service provision. This article looks at aspects of political and economic liberalisation in Uganda, involving devolution and outsourcing of service provision in Kampala city. It focuses on the city's experience with devolution and outsourcing of solid waste management. It shows that, pockets of resistance notwithstanding, the reforms enjoyed widespread popularity and led to many positive changes. In addition, it shows that they begot problems and encountered others that rendered the process of change more problematic than its advocates had anticipated. Its major conclusion is that while devolution and outsourcing are useful tools for improving service delivery, they cannot ensure long-term success in the absence of financial, technical and managerial capacity on the part of contractors and contracting authorities. Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||