588 research outputs found
A renormalization procedure for tensor models and scalar-tensor theories of gravity
Tensor models are more-index generalizations of the so-called matrix models,
and provide models of quantum gravity with the idea that spaces and general
relativity are emergent phenomena. In this paper, a renormalization procedure
for the tensor models whose dynamical variable is a totally symmetric real
three-tensor is discussed. It is proven that configurations with certain
Gaussian forms are the attractors of the three-tensor under the renormalization
procedure. Since these Gaussian configurations are parameterized by a scalar
and a symmetric two-tensor, it is argued that, in general situations, the
infrared dynamics of the tensor models should be described by scalar-tensor
theories of gravity.Comment: 20 pages, 3 figures, references added, minor correction
Temperature Effects Removal from Non-Stationary Bridge–Vehicle Interaction Signals for ML Damage Detection
The development of Structural Health Monitoring (SHM) and Non-Destructive Testing (NDT) techniques has rapidly evolved and matured over the past few decades. Advances in sensor technology have facilitated deploying SHM systems for large-scale structures and local NDT of structural members. Although both methods have been successfully applied to identify structural damage in various systems, Environmental and Operational Condition (EOC) variations can influence sensor measurements and mask damage signatures in the structural response. EOCs include environmental conditions, such as temperature, humidity, and wind, as well as operational conditions, such as mass loading, vibration, and boundary conditions. The effect of EOCs can significantly undermine the reliability and robustness of damage assessment technologies and limit their performance. Thus, successful SHM and NDT systems can compensate for changing EOCs. This paper provides a stateof-the-art review of the effects of EOCs on SHM and NDT systems. It presents recent developments
in advanced sensing technology, signal processing, and analysis techniques that aim to eliminate the masking effect of EOC variations and increase the damage sensitivity and performance of SHM and NDT systems. The paper concludes with current research challenges, trends, and recommendations
for future research directions
Matrix geometries and Matrix Models
We study a two parameter single trace 3-matrix model with SO(3) global
symmetry. The model has two phases, a fuzzy sphere phase and a matrix phase.
Configurations in the matrix phase are consistent with fluctuations around a
background of commuting matrices whose eigenvalues are confined to the interior
of a ball of radius R=2.0. We study the co-existence curve of the model and
find evidence that it has two distinct portions one with a discontinuous
internal energy yet critical fluctuations of the specific heat but only on the
low temperature side of the transition and the other portion has a continuous
internal energy with a discontinuous specific heat of finite jump. We study in
detail the eigenvalue distributions of different observables.Comment: 20 page
Effect of temperature and compression/decompression rates on high pressure inactivation of Listeria
The main objective of the present study was to evaluate the effect of temperature and different compression/ decompression rates on the efficiency of Listeria inactivation by HPP.
Stationary phase cultures of Listeria innocua were subjected to 300 MPa for 5 min at 4, 10, and 20 °C using different compression and decompression rates. Inactivation was more efficient at low temperature and with lowest compression and decompression rates (1.5 MPa s–1 and 3.2 MPa s–1, respectively).
Kinetics of pressure building up and decompression, as well as temperature, have a significant impact on the outcome of Listeria inactivation by HPP. The results may contribute to the design of HPP protocols that ensure food safety, while preserving nutritional and organoleptic properties better
Technological Devices in the Archives: A Policy Analysis
Doing research in the archive is the cornerstone of humanities scholarship.
Various archives institute policies regarding the use of technological
devices, such as mobile phones, laptops, and cameras in their reading rooms.
Such policies directly affect the scholars as the devices mediate the nature of
their interaction with the source materials in terms of capturing, organizing,
note taking, and record keeping for future use of found materials. In this paper,
we present our analysis of the policies of thirty archives regarding the use of
technology in their reading rooms. This policy analysis, along with data from
interviews of scholars and archivists, is intended to serve as a basis for developing
mobile applications for assisting scholars in their research activities. In this
paper we introduce an early prototype of such a mobile application—
AMTracker.Informatio
The impact of long term medical conditions on the outcomes of psychological therapy for depression and anxiety
Background: Long term conditions (LTC) often coexist with depression and anxiety. Aims: To assess the effectiveness of stepped care psychological therapies for patients with LTC. Method: Data from 28498 patients were analysed using regression to model depression (PHQ-9) and anxiety (GAD-7) outcomes. Post-treatment symptoms and effect sizes (d) were estimated for cases with and without LTC, controlling for covariates. The likelihood of access and response to intensive psychological interventions was also examined. Results: Higher post-treatment symptoms were predicted for patients with musculoskeletal problems (d = .22 to .27), COPD (d = .26 to .33), diabetes (d = .05 to .13) and psychotic disorders (d = .50 to .58). Most LTC were associated with greater odds of accessing high intensity therapies (HIT), yet HIT cases continued to have higher average post-treatment symptoms. Conclusions: Some LTC are associated with greater intensity of care and poorer outcomes after therapy
Probing the fuzzy sphere regularisation in simulations of the 3d \lambda \phi^4 model
We regularise the 3d \lambda \phi^4 model by discretising the Euclidean time
and representing the spatial part on a fuzzy sphere. The latter involves a
truncated expansion of the field in spherical harmonics. This yields a
numerically tractable formulation, which constitutes an unconventional
alternative to the lattice. In contrast to the 2d version, the radius R plays
an independent r\^{o}le. We explore the phase diagram in terms of R and the
cutoff, as well as the parameters m^2 and \lambda. Thus we identify the phases
of disorder, uniform order and non-uniform order. We compare the result to the
phase diagrams of the 3d model on a non-commutative torus, and of the 2d model
on a fuzzy sphere. Our data at strong coupling reproduce accurately the
behaviour of a matrix chain, which corresponds to the c=1-model in string
theory. This observation enables a conjecture about the thermodynamic limit.Comment: 31 pages, 15 figure
Preservation of sliced cooked ham at 25, 30 and 37°C under moderated pressure (hyperbaric storage) and comparison with refrigerated storage
The feasibility of hyperbaric storage (HS) to substitute refrigeration as a lower energetic cost alternative to refrigeration, for sliced cooked ham preservation was assessed by using temperatures and pressures ranging 25–37◦C and 25–150 MPa for 4 and 8 h.
At microbiological level, storage at 25 ◦C, 30 ◦C, and 37 ◦C, showed no effect on microbial growth at 25 MPa reaching levels similar to atmospheric pressure storage, around 5 log CFU/g for both total aerobic mesophiles (TAM) and lactic acid bacteria (LAB). Nevertheless, the storage at 50 MPa and 30 ◦C resulted in microbial growth inhibition, resulting in TAM and LAB counts similar to refrigeration, of about 3.8 log CFU/g for both the microorganisms.
Additionally, the increase of the storage pressure to 100–150 MPa resulted in microbial inacti-vation, leading to microbial loads of almost 1 log CFU/g lower than refrigeration. In general, hyperbaric stored sliced cooked ham showed physicochemical parameters similar to the refrigerated samples.
In conclusion, these results show that HS at uncontrolled (naturally variable room tem-perature conditions at 25–37 ◦C) is a promising alternative to refrigeration for cooked ham preservation. To this new preservation technology, no energetic costs are associated throughout storage, compared to refrigeration, needing only energy to generate the pressure and decompress, since no energy is required to maintain the pressure
A first study comparing preservation of a ready-to-eat soup under pressure (hyperbaric storage) at 25°C and 30°C with refrigeration
Hyperbaric storage (HS), storage under pressure at 25°C and 30°C, of a ready-to-eat (RTE) soup was studied and compared with refrigeration. Soup was stored at different time (4 and 8 h), temperature (4°C, 25°C, and 30°C), and pressure (0.1, 100, and 150 MPa) conditions, to compare microbial loads and physicochemical parameters. HS resulted in similar (microbial growth inhibition) to better (microbial inactivation) results compared to refrigeration, leading to equal and lower microbial loads, respectively, at the end of storage. Lower/higher pressure (100 vs. 150 MPa) and shorter/longer storage times (4 vs. 8 h) resulted in more pronounced microbial growth inhibition/microbial inactivation. Aerobic mesophiles showed less susceptibility to HS, compared to Enterobacteriaceae and yeast and molds. HS maintained generally the physicochemical parameters at values similar to refrigeration. Thus, HS with no need for temperature control throughout storage and so basically energetically costless, is a potential alternative to refrigeration
Variation in Magnetic Fabrics at Low Shock Pressure Due to Experimental Impact Cratering
Magnetic fabrics provide important clues for understanding impact cratering processes. However, only a few magnetic fabric studies for experimentally shocked material have been reported so far. In the framework of MEMIN (Multidisciplinary Experimental and Modeling Impact Research Network), we conducted two impact experiments on blocks of Maggia gneiss with the foliation oriented perpendicular (A38) and parallel (A37) to the target surface. Maggia gneiss has plenty of biotite bands forming a strong rock foliation. The bulk magnetic susceptibility varies from 0.376 × 10 to 1.298 × 10 SI in unshocked and from 0.443 × 10 to 3.940 × 10 SI in shocked gneiss. The thermomagnetic curves reveal a Verwey transition at −147 °C and a Curie temperature between 576 and 579 °C in unshocked and shocked samples, indicating nearly pure magnetite, which carries the magnetic fabrics. In A37 and A38 kinking is prominent from the point source down to a depth of 2 and 4.2 d (projectile diameter) or 1 and 2.1 cm, respectively. Kinking, folding, and fracturing changed the position of magnetite grains with respect to each other to reorient the magnetic fabrics. Reorientation of magnetic fabrics is conspicuous down to 20 d (10 cm) in A38, where no other impact‐related deformation is visible. The reorientation of magnetic fabrics may, therefore, aid in identifying impact processes at very low pressures, starting at 0.1 GPa, when other common indicators are absent
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