bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐destructive packaging seal strength analysis and leak detection using ultrasonic imaging
Authors: Pascall M. A. , Richtsmeier J. , Riemer J. , Farahbakhsh B. 
Published: April 2003

AbstractThis study investigated the effectiveness of ultrasonic imaging for non‐destructive assessment of seal strength in 335 ml polymeric trays. In the first part of this study, the experimental procedures involved filling sample trays with beef enchilada, then sealing at temperatures of 170–260°C for 5 s at 3 bar. Ultrasonic measurements were conducted using an immersion technique in pulse/echo mode. The captured signal amplitudes of the reflections from the samples were digitized and analysed to construct high‐resolution C‐scan ultrasonic images of the seals. The acquired data were statistically analysed for each sample and used as a basis for comparison with the seal (peel) strength, measured as the energy at break. The energy at break was obtained from destructive peel strength analysis, performed using a tensile testing frame. In the second part of this study, ultrasonic imaging was used to predict the performance of the heat sealer used to fabricate the test trays by comparing the seal quality of each of the four quadrants of the samples trays. This study also investigated the minimum channel leak size that could be detected using this ultrasound system. The results of the peel strength analyses showed that a direct correlation exists between seal strength and sealing temperature (170–227°C). Results of the ultrasonic imaging showed that the statistical scatter in the signal amplitude decreased as the sealing temperature increased. This reduction in the scatter of the signal amplitudes indicated a trend of increasing uniformity in the fusion of the two seal faces. Between 170°C and 193°C, sharp changes in the scatter were observed; however, little change was noted for sealing temperatures greater than 193°C, indicating that 204°C could be a minimum recommended sealing temperature. To confirm this result, a drop test analysis was performed on trays filled with beef enchilada and sealed at temperatures of 170–260°C for 5 s at 3 bar. Results of this drop test confirmed that 204°C was the minimum critical sealing temperature. Based on these results, ultrasonic imaging appeared to offer a promising non‐destructive method for the prediction of seal quality in polymeric trays, sealing equipment monitoring and identification of channel leaks ⩾20 µm in diameter, and is comparable with the more established destructive peel strength analytical method. Copyright © 2003 John Wiley & Sons, Ltd.
Packaging materials for fermented milk, part 2: solute‐induced changes and effects of material polarity and thickness on food quality
Authors: Jansson S. E. A. , Gallet G. , Hefti T. , Karlsson S. , Gedde U. W. , Hedenqvist M. S. 
Published: April 2003

AbstractThis work is a continuation of the application of a developed methodology for the selection of packaging material for a specific food product, in this case the ‘demanding’ food product: fermented milk. The effects of different packaging material parameters on the quality of fermented milk were studied. Food quality after storage was determined as a function of material polarity and pouch thickness by storing the liquid in pouches of different materials. The material polarity was varied by using laminates with polyethylene, poly(ethylene‐co‐vinyl alcohol) with two different ethylene contents and an aliphatic polyketone. The effects of pouch thickness were studied using high‐density polyethylene films of different thicknesses between 25 µm and 200 µm. The interactions between the milk product and the pouch material were analysed by oxygen and water permeability, gas chromatography–mass spectrometry and tensile testing. The CO2 and O2 contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis and the contents of Bifidobacteria, Enterobacteriaceae, yeast and mould. A trained taste panel determined the sensory properties. The content of CO2, and consequently the sparkling taste, increased with increasing polarity and/or pouch thickness. The CO2 content was affected more easily by changes in material polarity than by changes in pouch thickness. The increase in whey syneresis and the decrease in Bifidobacteria content with time were independent of material polarity and pouch thickness. The contents of Enterobacteriaceae, yeast and mould in the liquid were always below existing limits for foodstuffs. A newly developed method was used by which the CO2 and O2 permeabilities of the pouch/packaging could be estimated, using the kinetics of the gas composition in the pouch headspace. Permeability values, as estimated by the method, revealed that the CO2 production and the O2 consumption rates of the fermented milk were dependent on the CO2 and O2 headspace concentrations. An increase in permeability, determined by conventional methods, suggested that both the non‐polar and the polar polymers were plasticized by fermented milk. The plasticization was, however, modest and undetectable when the polyethylene tensile test data were analysed. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of ozone exposure on the structural, mechanical and barrier properties of select plastic packaging films
Authors: Ozen Banu F. , Mauer Lisa J. , Floros John D. 
Published: April 2003

AbstractThe effects of ozone (O3) gas exposure at various concentrations and treatment times on structural, mechanical and barrier properties of polyethylene and polyamide films were investigated. Changes in the structure of the films were monitored using an FT‐IR spectrometer. The results showed that O3 treatment affected polyethylene and polyamide films differently. While O3 treatment caused formation of oxygen‐containing functional groups and degradation of polymeric chains in polyethylene films, O3 treatment of polyamide films significantly increased the –C–N– stretch observed at 1125 cm−1 in the FT‐IR spectra. The changes in the mechanical properties of polyethylene films depended on the O3 treatment conditions (temperature and O3 concentration were the most significant), but an increase in tensile strength of polyamide films was observed regardless of the treatment conditions. Permeability to O2 for both types of films decreased with increasing O3 treatment time. Copyright © 2003 John Wiley & Sons, Ltd.
Prototropic tautomers of 5‐methylcytosine and enthalpy changes of their protonation, deprotonation, and deamination: Hybrid density functional B3LYP study
Authors: Tian Shan Xi , Xu Ke Zun 
Published: April 2003

AbstractMolecular and thermodynamic properties such as geometric parameters, dipole moments, vibrational frequencies, the first ionization potentials, relative tautomerization energies, and tautomeric equilibrium constants of all prototropic tautomers of 5‐methylcytosine have been studied at the hybrid density functional level B3LYP/6‐31+G(d,p). The methylation on the C5 atom does not lead to significant geometric deformation of the pyrimidine structures of the corresponding tautomers of cytosine, which maintains the similar stability order. The tautomeric species 2‐oxo‐4‐amino [T(0)], 2‐hydroxy‐4‐amino [T(1‐2s) and T(1‐2t)], and trans‐2‐oxo‐4‐imino [T(3‐4t)] are predominated in the gas phase. The zwitterionic conformers of tautomerism [T(1‐4)] and protonation [P(4), P(1‐2s‐4), P(1‐2t‐4), and P(1‐3‐4)] are investigated for the first time due to their close relationship with deamination during genetic repair. Enthalpy changes (ΔrH) of protonation, deprotonation, and deamination are calculated for these tautomeric species at room temperature; it is noted that the relative enthalpies [δ(ΔH)] of the tautomers are rationalized well in terms of a second‐order polynomial of the sum of the mean ΔrH values of protonation and deprotonation processes. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Time asymmetry, nonexponential decay, and complex eigenvalues in the theory and computation of resonance states
Authors: Nicolaides Cleanthes A. 
Published: April 2003

AbstractStationary‐state quantum mechanics presents no difficulties in defining and computing discrete excited states because they obey the rules established in the properties of Hilbert space. However, when this idealization has to be abandoned to formulate a theory of excited states dissipating into a continuous spectrum, the problem acquires additional interest in many fields of physics. In this article, the theory of resonances in the continuous spectrum is formulated as a problem of decaying states, whose treatment can entail time‐dependent as well as energy‐dependent theories. The author focuses on certain formal and computational issues and discusses their application to polyelectronic atomic states. It is argued that crucial to the theory is the understanding and computation of a multiparticle localized wavepacket, Ψ0, at t = 0, having a real energy E0. Assuming this as the origin, without memory of the excitation process, the author discusses aspects of time‐dependent dynamics, for t ≈ 0 as well as for t → ∞, and the possible significance of nonexponential decay in the understanding of time asymmetry. Also discussed is the origin of the complex eigenvalue Schrödinger equation (CESE) satisfied by resonance states and the state‐specific methodology for its solution. The complex eigenvalue drives the decay exponentially, with a rate Γ, to a good approximation. It is connected to E0 via analytic continuation of the complex self‐energy function, A(z), (z is complex), into the second Riemann sheet, or, via the imposition of outgoing wave boundary conditions on the stationary state Schrödinger equation satisfied by the Fano standing wave superposition in the vicinity of E0. If the nondecay amplitude, G(t), is evaluated by inserting the unit operator I = ∫dE|E><E| G(t) = < Ψ0|e−iHt|Ψ0 >, then the resulting spectral function is real, g(E) =|<Ψ0|E>|2, and does not differentiate between positive and negative times. The introduction of time asymmetry, which is associated with irreversibility, is achieved by starting from < Ψ0|θ(t)e−iHt|Ψ0 >, where θ(t) is the step function at the discontinuity point t = 0. In this case, the spectral function is complex. Within the range of validity of exponential decay, the complex spectral function is the same as the coefficient of Ψ0 in the theory of the CESE. A calculation of G(t) using the simple pole approximation and the constraints that t > 0 and E > 0 results in a nonexponential decay (NED) correction for t ≫ 1/Γ that is different than when a real g(E) is used, representing the contribution of both “in” and “out” states. Earlier formal and computational work has shown that resonance states close to threshold are good candidates for NED to acquire nonnegligible magnitude. In this context, a pump‐probe laser experiment in atomic physics is proposed, using as a paradigm the He− 1s2p2 4P shape resonance. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Solution of periodic Poisson's equation and the Hartree–Fock approach for solids with extended electron states: Application to linear augmented plane wave method
Authors: Nikolaev A. V. , Dyachkov P. N. 
Published: April 2003

AbstractWe formulate a Hartree–Fock‐LAPW method for electronic band structure calculations. The method is based on the Hartree–Fock–Roothaan approach for solids with extended electron states and closed core shells where the basis functions of itinerant electrons are linear augmented plane waves. All interactions within the restricted Hartree–Fock approach are analyzed and in principle can be taken into account. In particular, we obtained the matrix elements for the exchange interactions of extended states and the crystal electric field effects. To calculate the matrix elements of exchange for extended states, we first introduce an auxiliary potential and then integrate it with an effective charge density corresponding to the electron exchange transition under consideration. The problem of finding the auxiliary potential is solved by using the strategy of the full potential LAPW approach, which is based on the general solution of periodic Poisson's equation. Here, we use an original technique for the general solution of periodic Poisson's equation and multipole expansions of electron densities. We apply the technique to obtain periodic potentials of the face‐centered cubic lattice and discuss its accuracy and convergence in comparison with other methods. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Soft systems methodology and dialectics in an information environment: a case study of the Battle of Britain
Authors: Robinson Bruce , Wilson Francis 
Published: April 2003

AbstractIn the Checkland and Holwell (1998) book Information, Systems and Information Systems an explanatory framework for soft systems methodology (SSM) is supported by the deployment of a case study of the Battle of Britain. In this paper the authors conduct an analysis of this historical account and identify the failure of SSM to provide an adequate explanation of these historical events. It is argued that through the use of materialist dialectics a more satisfactory understanding of the nature of the processes of abstraction and the bounding of problems and systems becomes available. Concepts from dialectics are applied to show how, and why, the differences between the two accounts reflect different methods of conceptualization of an information environment. In this light, we point to similarities and differences between the two meta‐frameworks used: SSM and materialist dialectics. Copyright © 2002 John Wiley & Sons, Ltd.
Factors that induce change in information systems
Authors: Malmsjö Anders , Övelius Erika 
Published: April 2003

AbstractChange cannot effectively be dealt with unless the nature of change is understood. This attitude to handling change is a point of departure for this work. Society changes, and conditions for organizations change. This will have a critical effect on the conditions for information systems. If necessary corrections are not made to the information system due to new conditions based on new demands on the information system, the information system will eventually be a system that no one will ask for. The purpose of this work is to specify the basis for making adequate corrections on information systems due to new conditions. Change factors, which will influence the conditions for an information system, have been identified by analysing studies in the literature where change factors that induce change to organizations are dealt with. A synthesis of change factors on the level of the organization has been transformed to the level of the individual, where the actual interaction between the information system and its context takes place. Furthermore, an empirical study based on approximately 150 interviews considering users' information needs in three Swedish government authorities has been considered in a synthesis. Based on that the following change factors have been found:external factors: type of work performed, working climate, time at disposal, competition, technology, laws and regulations, economy, feedback, environmental demands and expectations, culture, conflicts;internal factors: stress, experience, habits and motivation. Copyright © 2003 John Wiley & Sons, Ltd.
All‐uses testing of shared memory parallel programs
Authors: Yang Cheer‐Sun D. , Pollock Lori L. 
Published: April 2003

AbstractParallelism has become a way of life for many scientific programmers. A significant challenge in bringing the power of parallel machines to these programmers is providing them with a suite of software tools similar to the tools that sequential programmers currently utilize. Unfortunately, writing correct parallel programs remains a challenging task.In particular, automatic or semi‐automatic testing tools for parallel programs are lacking. This paper takes a first step in developing an approach to providing all‐uses coverage for parallel programs. A testing framework and theoretical foundations for structural testing are presented, including test data adequacy criteria and hierarchy, formulation and illustration of all‐uses testing problems, classification of all‐uses test cases for parallel programs, and both theoretical and empirical results with regard to what can be achieved with all‐uses coverage for parallel programs. Copyright © 2003 John Wiley & Sons, Ltd.
Individual Blade Pitch Control for Load Reduction
Authors: Bossanyi E. A. 
Published: April 2003

AbstractIf a pitch‐regulated wind turbine has individual pitch actuators for each blade, the possibility arises to send different pitch angle demands to each blade. The possibility of using this as a way of reducing loads has been suggested many times over the years, but the idea has yet to gain full commercial acceptance. There are a number of reasons why this situation may be set to change, and very significant load reductions can result. Copyright © 2002 John Wiley & Sons, Ltd.
Improved Modal Dynamics of Wind Turbines to Avoid Stall‐induced Vibrations
Authors: Hansen M. H. 
Published: April 2003

AbstractStall‐induced edgewise blade vibrations have occasionally been observed on three‐bladed wind turbines over the last decade. Experiments and numerical simulations have shown that these blade vibrations are related to certain vibration modes of the turbines. A recent experiment with a 600 kW turbine has shown that a backward whirling mode associated with edgewise blade vibrations is less aerodynamically damped than the corresponding forward whirling mode. In this article the mode shapes of the particular turbine are analysed, based on a simplified turbine model described in a multi‐blade formulation. It is shown that the vibrations of the blades for the backward and forward edgewise whirling modes are different, which can explain the measured difference in aerodynamic damping. The modal dynamics of the entire turbine is important for stability assessments; blade‐only analysis can be misleading. In some cases the modal dynamics may even be improved to avoid stall‐induced vibrations. Copyright © 2003 John Wiley & Sons, Ltd.
Feeding behaviour and associated sensory mechanisms of stage I–III phyllosoma of Jasus edwardsii and Jasus verreauxi
Authors: Cox Serena L. , Bruce Michael P. 
Published: April 2003

The feeding behaviour of stage I–III phyllosoma of the spiny lobsters Jasus edwardsii and Jasus verreauxi was recorded to determine the sequence of events and sensory mechanisms involved in the feeding process. All phyllosoma exhibited a characteristic tumbling behaviour prior to making contact with an individual Artemia and feeding behaviour was similar between the two species. Tactile contact with pereiopods 1 or 2 was necessary to initiate a prey capture response which involved spearing of Artemia, using the terminal dactyl present on these two pereiopods and then passing the prey forward to the mouth with the maxillipeds.Scanning electron microscopy (SEM) of the pereiopods revealed two morphologically distinct receptors present on the distal segments. These receptors are suggested to have tactile and chemoreceptive roles.
Integration by parts formulas involving generalized Fourier-Feynman transforms on function space
Authors: Chang Seung , Choi Jae , Skoug David 
Published: April 2003

In an upcoming paper, Chang and Skoug used a generalized Brownian motion process to define a generalized analytic Feynman integral and a generalized analytic Fourier-Feynman transform. In this paper we establish several integration by parts formulas involving generalized Feynman integrals, generalized Fourier-Feynman transforms, and the first variation of functionals of the form

F
(
x
)
=
f
(
⟨

α

1

,
x
⟩
,
…
,
⟨

α

n

,
x
⟩
)

F(x)=f(\langle \alpha _{1} , x\rangle , \dots , \langle \alpha _{n} , x\rangle )

where

⟨

α
,
x

⟩

\langle {\alpha ,x}\rangle

denotes the Paley-Wiener-Zygmund stochastic integral

∫

0

T

α
(
t
)
d
x
(
t
)

\int _{0}^{T} \alpha (t) d x(t)

.
Strongly indefinite functionals and multiple solutions of elliptic systems
Authors: De Figueiredo D. , Ding Y. 
Published: April 2003

We study existence and multiplicity of solutions of the elliptic system\[{−Δu=Hu(x,u,v)amp;in Ω,−Δv=−Hv(x,u,v)amp;in Ω,u(x)=v(x)=0on ∂Ω,\begin {cases} -\Delta u =H_u(x,u,v) & \text {in $\Omega $}, \\ -\Delta v =-H_v(x,u,v) & \text {in $\Omega $}, \quad u(x) = v(x) = 0 \quad \text {on $\partial \Omega $}, \end {cases}\]whereΩ⊂RN,N≥3\Omega \subset \mathbb {R}^N, N\geq 3, is a smooth bounded domain andH∈C1(Ω¯×R2,R)H\in \mathcal {C}^1(\bar {\Omega }\times \mathbb {R}^2, \mathbb {R}). We assume that the nonlinear term\[H(x,u,v)∼|u|p+|v|q+R(x,u,v) with lim|(u,v)|→∞R(x,u,v)|u|p+|v|q=0,H(x,u,v)\sim |u|^p + |v|^q + R(x,u,v) \ \ \text {with} \ \ \lim _{|(u,v)|\to \infty }\frac {R(x,u,v)}{|u|^p+|v|^q}=0,\]wherep∈(1, 2∗)p\in (1, \ 2^*),2∗:=2N/(N−2)2^*:=2N/(N-2), andq∈(1, ∞)q\in (1, \ \infty ). So some supercritical systems are included. Nontrivial solutions are obtained. WhenH(x,u,v)H(x,u,v)is even in(u,v)(u,v), we show that the system possesses a sequence of solutions associated with a sequence of positive energies (resp. negative energies) going toward infinity (resp. zero) ifp>2p>2(resp.p>2p>2). All results are proved using variational methods. Some new critical point theorems for strongly indefinite functionals are proved.
Criteria for large deviations
Authors: Comman Henri 
Published: April 2003

We give the general variational form of
\[

lim sup
(

∫
X

e

h
(
x
)

/

t

α

μ

α

(
d
x
)

)

t

α

\limsup (\int _X e^{h(x)/t_{\alpha }}\mu _{\alpha }(dx))^{t_{\alpha }}

\]
for any bounded above Borel measurable function

h
h

on a topological space

X
X

, where

(

μ

α

)

(\mu _{\alpha })

is a net of Borel probability measures on

X
X

, and

(

t

α

)

(t_{\alpha })

a net in

]
0
,
∞
[

]0,\infty [

converging to

0
0

. When

X
X

is normal, we obtain a criterion in order to have a limit in the above expression for all

h
h

continuous bounded, and deduce new criteria of a large deviation principle with not necessarily tight rate function; this allows us to remove the tightness hypothesis in various classical theorems.
Stability of small amplitude boundary layers for mixed hyperbolic-parabolic systems
Authors: Rousset F. 
Published: April 2003

We consider an initial boundary value problem for a symmetrizable mixed hyperbolic-parabolic system of conservation laws with a small viscosity

ε
\varepsilon

,

u
t
ε

+
F
(

u
ε

)
x

=
ε
(
B
(

u
ε

)

u
x
ε

)
x

.

u^\varepsilon _t+F(u^\varepsilon )_x =\varepsilon (B(u^\varepsilon ) u^\varepsilon _x )_x .

When the boundary is noncharacteristic for both the viscous and the inviscid system, and the boundary condition dissipative, we show that

u
ε

u^\varepsilon

converges to a solution of the inviscid system before the formation of shocks if the amplitude of the boundary layer is sufficiently small. This generalizes previous results obtained for

B
B

invertible and the linear study of Serre and Zumbrun obtained for a pure Dirichlet’s boundary condition.