341 research outputs found
Elasticity Solution of an Adhesively Bonded Cover Plate of Various Geometries
The plane strain of adhesively bonded structures consisting of two different isotropic adherends is considered. By expressing the x-y components of the displacements in terms of Fourier integrals and using the corresponding boundary and continuity conditions, the integral equations for the general problem are obtained and solved numerically by applying Gauss-Chebyshev integration scheme. The shear and the normal stresses in the adhesive are calculated for various geometries and material properties for a stiffened plate under uniaxial tension. Numerical results involving the stress intensity factors and the strain energy release rate are presented. The closed-form expressions for the Fredholm kernels are provided to obtain the solution for an arbitrary geometry and material properties. For the general geometry, the contribution of the normal stress is quite significant, while for symmetric geometries, the shear stress is dominant, the normal stress vanishes if the adherends are of the same material and the same thickness
Multicomponent Strongly Interacting Few-Fermion Systems in One Dimension
The paper examines a trapped one-dimensional system of multicomponent
spinless fermions that interact with a zero-range two-body potential. We show
that when the repulsion between particles is very large the system can be
approached analytically. To illustrate this analytical approach we consider a
simple system of three distinguishable particles, which can be addressed
experimentally. For this system we show that for infinite repulsion the energy
spectrum is sixfold degenerate. We also show that this degeneracy is partially
lifted for finitely large repulsion for which we find and describe
corresponding wave functions.Comment: Paper in connection with the 22nd European Conference on Few-Body
Problems in Physics, Krakow, Poland, 9-13 September 201
A Solvable Model for Decoupling of Interacting Clusters
We consider M clusters of interacting particles, whose in-group interactions
are arbitrary, and inter-group interactions are approximated by oscillator
potentials. We show that there are masses and frequencies that decouple the
in-group and inter-group degrees of freedom, which reduces the initial problem
to M independent problems that describe each of the relative in-group systems.
The dynamics of the M center-of-mass coordinates is described by the
analytically solvable problem of M coupled harmonic oscillators. This paper
derives and discusses these decoupling conditions. Furthermore, to illustrate
our findings, we consider a charged impurity interacting with a ring of ions.
We argue that the impurity can be used to probe the center-of-mass dynamics of
the ions.Comment: Version accepted for publication in EP
Computational Modeling of Vehicle Radiators Using Porous Medium Approach
A common tool for the determination of thermal characteristics of vehicle radiators is the experimental testing. However, experimental testing may not be feasible considering the cost and labor-time. Basic understanding of the past experimental data and analytical/computational modeling can significantly enhance the effectiveness of the design and development phase. One such computational modeling technique is the utilization of computational fluid dynamics (CFD) analysis to predict the thermal characteristics of a vehicle radiator. However, CFD models are also not suitable to be used as a design tool since considerable amount of computational power and time is required due to the multiple length scales involved in the problem, especially the small-scale geometric details associated with the fins. Although fins introduce a significant complexity for the problem, the repetitive and/or regular structure of the fins enables the porous medium based modeling. By porous modeling, a memory and time efficient computational model can be developed and implemented as an efficient design tool for radiators. In this work, a computational methodology is described to obtain the hydrodynamic and thermal characteristics of a vehicle radiator. Although the proposed methodology is discussed in the context of a vehicle radiator, the proposed methodology can be implemented to any compact heat exchanger with repetitive fin structures which is an important problem for many industrial applications
Hvordan kan positivt lederskap bidra til vellykket resultatstyring?
Masteroppgave i bedriftsledelse (MBA) - Universitetet i Nordland, 201
Improving osteoarthritis management in primary healthcare: results from a quasi-experimental study
Background
To improve quality of care for patients with hip and knee osteoarthritis (OA), general practitioners (GPs) and physiotherapists (PTs) in a Norwegian municipality initiated an intervention. The intervention aimed to increase provision of core OA treatment (information, exercise, and weight control) prior to referral for surgery, rational use of imaging for assessing OA and improve communication between healthcare professionals. This study assessed the effectiveness of this intervention.
Methods
Forty-eight PTs and one hundred one GPs were invited to the intervention that included two interactive workshops outlining best practice and an accompanying template for PT discharge reports. Using interrupted time series research design, the study period was divided into three: pre-implementation, transition (implementation) and post-implementation. Comparing the change between pre- and post-implementation, the primary outcome was patient-reported quality of OA care measured with the OsteoArthritis Quality Indicator questionnaire. Secondary outcomes were number of PT discharge reports, information included in GP referral letters to orthopaedic surgeon, the proportion of GP referral letters indicating use of core treatment, and the use of imaging within OA assessment. Analyses involved linear mixed and logistic regression models.
Results
The PT workshop had 30 attendees, and 31 PTs and 33 GPs attended the multidisciplinary workshop. Two hundred eight and one hundred twenty-five patients completed the questionnaire during pre- and post-implementation, respectively. The adjusted model showed a small, statistically non-significant, increase in mean total score for quality of OA care (mean change = 4.96, 95% CI -0.18, 10.12, p:0.057), which was mainly related to items on OA core treatment. Patients had higher odds of reporting receipt of information on treatment alternatives (odds ratio (OR) 1.9, 95% CI 1.08, 3.24) and on self-management (OR 2.4, 95% CI 1.33, 4.32) in the post-implementation phase. There was a small, statistically non-significant, increase in the proportion of GP referral letters indicating prior use of core treatment modalities. There were negligible changes in the number of PT discharge reports, in the information included in the GP referral letters, and in the use of imaging for OA assessment.
Conclusion
This study suggests that a primary care intervention including two inter-active workshops can shift the quality of care towards best practice recommendations.
Trial registration
ClinicalTrials.gov: NCT02876120.publishedVersio
Clusters in Separated Tubes of Tilted Dipoles
A few-body cluster is a building block of a many-body system in a gas phase provided
the temperature at most is of the order of the binding energy of this cluster. Here we illustrate this
statement by considering a system of tubes filled with dipolar distinguishable particles. We calculate
the partition function, which determines the probability to find a few-body cluster at a given
temperature. The input for our calculations — the energies of few-body clusters — is estimated using
the harmonic approximation. We first describe and demonstrate the validity of our numerical
procedure. Then we discuss the results featuring melting of the zero-temperature many-body state
into a gas of free particles and few-body clusters. For temperature higher than its binding energy
threshold, the dimers overwhelmingly dominate the ensemble, where the remaining probability is in
free particles. At very high temperatures free (harmonic oscillator trap-bound) particle dominance
is eventually reached. This structure evolution appears both for one and two particles in each
layer providing crucial information about the behavior of ultracold dipolar gases. The investigation
addresses the transition region between few- and many-body physics as a function of temperature
using a system of ten dipoles in five tubes
Tibial torus and toddler's fractures misdiagnosed as transient synovitis: a case series
<p>Abstract</p> <p>Introduction</p> <p>The high incidence of transient synovitis in early childhood makes it the first suspected pathology in a limping child. Trauma, which has long been regarded as a causative factor for transient synovitis, may be underestimated in a non-cooperative toddler.</p> <p>After excluding most serious conditions, such as septic arthritis, a speculative diagnosis of transient synovitis can be made, and this can easily mask a subtle musculoskeletal injury.</p> <p>Case presentations</p> <p>We report the cases of three Caucasian patients (two boys, aged 20-months- and three-years-old, and one girl, aged two-years-old), with tibial torus and toddler's fractures which were late-diagnosed due to an initial misdiagnosis of transient synovitis of the hip.</p> <p>Conclusion</p> <p>In a non-cooperative child musculoskeletal trauma can be mistaken as a simple causative factor for transient synovitis of the hip and this can easily prevent further investigation for a possible subtle musculoskeletal injury of the lower extremities.</p> <p>Our experience with the presented cases suggests the need to be more vigilant in the differential diagnosis of transient synovitis in young children.</p
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