159 research outputs found
Response to âShear ImpossibilityâComments on âVoid Growth by Dislocation Emissionâ and âVoid Growth in Metalsââ
We thank the authors of Ref. [1] for their comments and interest in our work [2], [3], [4], [5] and [6]. We agree that the emission of shear loops on one single shear plane cannot lead to void growth. However, our simulations suggest that coordinated shear on non-parallel planes can lead to void growth/shrinkage [3], [4] and [5]. Detailed descriptions of this process are still being worked out and represent an exciting area for future research. Thus, there seem to be two separate dislocation mechanisms operating either sequentially or simultaneously: shear and prismatic loop emission. Whereas prismatic loops are well known and have been extensively documented, the postulation of âspecialâ shear loops is novel. The authors [1] have correctly pointed out that special restrictions need to be applied to these shear loops, something not mentioned in Refs. [2], [3], [4], [5] and [6].Fil: Bringa, Eduardo Marcial. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Lubarda, V. A.. University of California at San Diego; Estados UnidosFil: Meyers, M. A.. University of California at San Diego; Estados Unido
Lagrangian formulation for noncommutative nonlinear systems
In this work we use the well known formalism developed by Faddeev and Jackiw
to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme
and O(3) nonlinear sigma models. The final result is the Lagrangian
formulations for the noncommutative versions of both models. The possibility of
obtaining different noncommutative versions for these nonlinear systems is
demonstrated.Comment: 8 pages. Revex 4.
Evaluation of a Combined MHE-NMPC Approach to Handle Plant-Model Mismatch in a Rotary Tablet Press
The transition from batch to continuous processes in the pharmaceutical industry has been driven by the potential improvement in process controllability, product quality homogeneity, and reduction of material inventory. A quality-by-control (QbC) approach has been implemented in a variety of pharmaceutical product manufacturing modalities to increase product quality through a three-level hierarchical control structure. In the implementation of the QbC approach it is common practice to simplify control algorithms by utilizing linearized models with constant model parameters. Nonlinear model predictive control (NMPC) can effectively deliver control functionality for highly sensitive variations and nonlinear multiple-input-multiple-output (MIMO) systems, which is essential for the highly regulated pharmaceutical manufacturing industry. This work focuses on developing and implementing NMPC in continuous manufacturing of solid dosage forms. To mitigate control degradation caused by plant-model mismatch, careful monitoring and continuous improvement strategies are studied. When moving horizon estimation (MHE) is integrated with NMPC, historical data in the past time window together with real-time data from the sensor network enable state estimation and accurate tracking of the highly sensitive model parameters. The adaptive model used in the NMPC strategy can compensate for process uncertainties, further reducing plant-model mismatch effects. The nonlinear mechanistic model used in both MHE and NMPC can predict the essential but complex powder properties and provide physical interpretation of abnormal events. The adaptive NMPC implementation and its real-time control performance analysis and practical applicability are demonstrated through a series of illustrative examples that highlight the effectiveness of the proposed approach for different scenarios of plant-model mismatch, while also incorporating glidant effects
From coinductive proofs to exact real arithmetic: theory and applications
Based on a new coinductive characterization of continuous functions we
extract certified programs for exact real number computation from constructive
proofs. The extracted programs construct and combine exact real number
algorithms with respect to the binary signed digit representation of real
numbers. The data type corresponding to the coinductive definition of
continuous functions consists of finitely branching non-wellfounded trees
describing when the algorithm writes and reads digits. We discuss several
examples including the extraction of programs for polynomials up to degree two
and the definite integral of continuous maps
Ambient temperature and mortality due to acute myocardial infarction in Brazil: an ecological study of time-series analyses
Ambient temperature may lead to decompensation of cardiovascular diseases and deaths by acute myocardial infarction (AMI). Little is known about this relationship in South American countries located in regions of a hot climate. This study aims to investigate the effects of ambient temperature on mortality due to AMI in six Brazilian micro-regions, which present different climates. We analyzed daily records of deaths by AMI between 1996 and 2013. We estimated the accumulate relative and attributable risks with lags of up to 14 days, using distributed non-linear lag model. Micro-regions that were closest to the equator did not show an association between temperature and mortality. The lowest risk temperatures varied between 22 °C and 28 °C, in the Southern region of Brazil and the Midwest region, respectively. Low temperatures associated with the highest mortality risk were observed in the same areas, varying between 5 °C and 15 °C. The number of deaths attributed to cold temperatures varied from 176/year in Brasilia to 661/year in São Paulo and those deaths attributed to hot temperatures in Rio de Janeiro amounted to 115/year. We showed the relative risk and the attributable risk of warmer and colder days in tropical regions. The estimate of the number of deaths due to climate, varying according to each area, is a way of bringing information to those responsible for health policies based on easily-understood measurements
Regression of Self-care Practices on Reducing Burnout among Public High School Teachers of Laguna, Philippines
Most teachers experience a fair share of job stress and pressure at their workplace. Being burnt out has always influenced a teacherâs self-efficacy and productivity at work. This study investigated the level of self-care and burnout among high school teachers and the predictive nature of self-care on burnout. A stratified clustered sample of secondary public school teachers across five City Schools Divisions of Laguna, Philippines, voluntarily participated. The study employed a descriptive correlational research design to address the research questions. A sociodemographic questionnaire, the Self-care Assessment Worksheet, and the Maslach Burnout Inventory-Educator Survey were used to collect information through an online platform. The results showed that the teachers expressed high levels of physical, emotional, spiritual, and workplace self-care practices and a moderate level of psychological self-care. Across burnout dimensions, the teachers are experiencing moderate levels of emotional exhaustion, depersonalization, and personal accomplishment. Correlation analysis established significant relationships between all dimensions of self-care and personal accomplishment. Regression analysis revealed the predictive ability of workplace self-care practices on personal accomplishment. The findings presented implications and provided recommendations
Noncommutative cosmological models coupled to a perfect fluid and a cosmological constant
In this work we carry out a noncommutative analysis of several
Friedmann-Robert-Walker models, coupled to different types of perfect fluids
and in the presence of a cosmological constant. The classical field equations
are modified, by the introduction of a shift operator, in order to introduce
noncommutativity in these models. We notice that the noncommutative versions of
these models show several relevant differences with respect to the
correspondent commutative ones.Comment: 27 pages. 7 figures. JHEP style.arXiv admin note: substantial text
overlap with arXiv:1104.481
Side chain engineering in indacenodithiophene- co -benzothiadiazole and its impact on mixed ionicâelectronic transport properties
Organic semiconductors are increasingly being decorated with hydrophilic solubilising chains to create materials that can function as mixed ionicâelectronic conductors, which are promising candidates for interfacing biological systems with organic electronics. While numerous organic semiconductors, including p- and n-type materials, small molecules and polymers, have been successfully tailored to encompass mixed conduction properties, common to all these systems is that they have been semicrystalline materials. Here, we explore how side chain engineering in the nano-crystalline indacenodithiophene-co-benzothiadiazole (IDTBT) polymer can be used to instil ionic transport properties and how this in turn influences the electronic transport properties. This allows us to ultimately assess the mixed ionicâelectronic transport properties of these new IDTBT polymers using the organic electrochemical transistor as the testing platform. Using a complementary experimental and computational approach, we find that polar IDTBT derivatives can be infiltrated by water and solvated ions, they can be electrochemically doped efficiently in aqueous electrolyte with fast doping kinetics, and upon aqueous swelling there is no deterioration of the close interchain contacts that are vital for efficient charge transport in the IDTBT system. Despite these promising attributes, mixed ionicâelectronic charge transport properties are surprisingly poor in all the polar IDTBT derivatives. Albeit a âânegativeââ result, this finding clearly contradicts established side chain engineering rules for mixed ionicâelectronic conductors, which motivated our continued investigation of this system. We eventually find this anomalous behaviour to be caused by increasing energetic disorder in the polymers with increasing polar side chain content. We have investigated computationally how the polar side chain motifs contribute to this detrimental energetic inhomogeneity and ultimately use the learnings to propose new molecular design criteria for side chains that can facilitate ion transport without impeding electronic transport
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