284 research outputs found

    Optimization of an Adsorbed Natural Gas System with Phase Change Material using the Topology Optimization Method

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    Abstract. Natural Gas has been drawing industrial sectors attention as a promising alternative fuel. This solutions attractiveness depends on the quality and efficiency of the storage and transport methods employed. Porous media are known to be an efficient manner to store natural gas by the adsorption mechanism, also known as Adsorbed Natural Gas (ANG). Temperatureexerts significant influence on adsorption efficiency. Studies applying Phase Change Materials (PCM) as heat exchanger in ANG systems suggests the combination improves the vessel capacity and adsorption and desorption rates behavior. In addition, the PCM bodies shape and position inside adsorption systems greatly affects the benefits they bring. For this reason, theTopology Optimization Method (TOM) is indicated for this problem. The topology optimization method is a versatile tool for material distribution inside a domain and in the last few decades its capabilities of exploring manufacturing process characteristics as well as its implementation have been improved. This study aims to increase the capacity and performance of Adsorbed Natural Gas (ANG) Vessels using TOM to distribute PCM material in the vessel interior. Thephysical model consider a coupled heat and mass transfer trough an ANG vessel with PCM in its interior, the boundary conditions are dictated by a pressure input in the vessels extremity and the natural convection on the vessels walls. FEniCS Project libraries are employed in the governing equations implementation and to work the solution for the differential equations and dolphin-adjoint libraries are applied to perform the sensitivities calculus. The project variable for the optimization is defined as the PCM distribution inside the vessel. Thermal properties corrections are performed according to an analytical solution for the phase change problem.Phase change enthalpy corrections are performed in the level of the variational problem to model the phase change phenomena. The amount of heat transferred to the phase change enthalpy dictates the phase composition in the domain. The implementation benefits the topology optimization approach as it maintains the duality between the adsorbent volume to adsorb gas and the PCM volume to store heat. An experimental work from the literature is modelled andcompared to the numerical results for software validation and model properties calibration. As results a 2D ANG vessel optimization is performed, the final topologies are presented and their total adsorption volume and charging/discharging time are compared.Keywords: Adsorption, Optimization, PCM, ANG, Desorptio

    Comorbidities are Frequent in Patients with Gastroesophageal Reflux Disease in a Tertiary Health Care Hospital

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    INTRODUCTION: Several aspects of gastroesophageal reflux disease (GERD) have been studied, but the frequency of comorbidities is not yet fully understood. OBJECTIVES: To study the prevalence of GERD comorbidities in a tertiary care hospital. METHODS: We prospectively studied 670 consecutive adult patients from the outpatient department of our facility. A diagnosis was established using clinical, endoscopic and/or pHmetry-related findings. Each patient's medical file was reviewed with respect to the presence of other medical conditions and diagnoses. RESULTS: Of the 670 patients, 459 (68.6%) were female, and the mean age was 55.94 (17-80 years). We registered 316 patients (47.1%) with the erosive form of GERD and 354 patients (52.9%) with the non-erosive form. A total of 1,664 instances of comorbidities were recorded in 586 patients (87.5%), with the most common being arterial hypertension (21%), hypercholesterolemia (9%), obesity (9%), type II diabetes mellitus (5%) and depression (4%). Two or more comorbidities were present in 437 individuals (64.8%). The occurrence of comorbidities increased with age and was higher in patients with the non-erosive form of GERD. CONCLUSIONS: In a tertiary referral population, comorbidities were very common, and these may have worsened the already impaired health-related quality of life of these patients. Clinicians caring for GERD patients in this setting must be aware of the likelihood and nature of comorbid disorders and their impact on disease presentation and patient management

    Tri-n-butyltin Hydride-Mediated radical reactions of ortho-and meta-Iodobenzamides to synthesize benzomacrolactams: surprising formation of biphenyl compounds from meta-regioisomers

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    Reactions of methyl 4-O-allyl-2,3-di-O-benzyl-6-deoxy-6-(3-iodobenzoylamino)-α-D-galactopyranoside, its gluco epimer, methyl 2,3-di-O-benzyl-6-deoxy-6-(3-iodobenzoylamino)-4-O-(1-pentenyl)-α-D-glucopyranoside and its ortho-regioisomer with tri-n-butyltin hydride were performed in different conditions. Depending on reaction conditions the three meta-iodo isomers gave a surprising amount of biphenyl compounds. The 2-iodo isomer led only to the undesired but expected hydrogenolysis product. No cyclized products were isolated in all the reactions. The structures of the new biphenyl products were elucidated by ¹H and 13C NMR spectroscopy, DEPT, COSY, HMQC and HMBC experiments and ESI-MS/MS. Mechanisms for the formation of these new biphenyl derivatives and hypotheses to explain the different outcomes for radical reactions of 3- or 2-iodobenzamides were presented

    ANN multiscale model of anti-HIV Drugs activity vs AIDS prevalence in the US at county level based on information indices of molecular graphs and social networks

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    [Abstract] This work is aimed at describing the workflow for a methodology that combines chemoinformatics and pharmacoepidemiology methods and at reporting the first predictive model developed with this methodology. The new model is able to predict complex networks of AIDS prevalence in the US counties, taking into consideration the social determinants and activity/structure of anti-HIV drugs in preclinical assays. We trained different Artificial Neural Networks (ANNs) using as input information indices of social networks and molecular graphs. We used a Shannon information index based on the Gini coefficient to quantify the effect of income inequality in the social network. We obtained the data on AIDS prevalence and the Gini coefficient from the AIDSVu database of Emory University. We also used the Balaban information indices to quantify changes in the chemical structure of anti-HIV drugs. We obtained the data on anti-HIV drug activity and structure (SMILE codes) from the ChEMBL database. Last, we used Box-Jenkins moving average operators to quantify information about the deviations of drugs with respect to data subsets of reference (targets, organisms, experimental parameters, protocols). The best model found was a Linear Neural Network (LNN) with values of Accuracy, Specificity, and Sensitivity above 0.76 and AUROC > 0.80 in training and external validation series. This model generates a complex network of AIDS prevalence in the US at county level with respect to the preclinical activity of anti-HIV drugs in preclinical assays. To train/validate the model and predict the complex network we needed to analyze 43,249 data points including values of AIDS prevalence in 2,310 counties in the US vs ChEMBL results for 21,582 unique drugs, 9 viral or human protein targets, 4,856 protocols, and 10 possible experimental measures.Ministerio de Educación, Cultura y Deportes; AGL2011-30563-C03-0

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Novel Strains of Mice Deficient for the Vesicular Acetylcholine Transporter: Insights on Transcriptional Regulation and Control of Locomotor Behavior

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    Defining the contribution of acetylcholine to specific behaviors has been challenging, mainly because of the difficulty in generating suitable animal models of cholinergic dysfunction. We have recently shown that, by targeting the vesicular acetylcholine transporter (VAChT) gene, it is possible to generate genetically modified mice with cholinergic deficiency. Here we describe novel VAChT mutant lines. VAChT gene is embedded within the first intron of the choline acetyltransferase (ChAT) gene, which provides a unique arrangement and regulation for these two genes. We generated a VAChT allele that is flanked by loxP sequences and carries the resistance cassette placed in a ChAT intronic region (FloxNeo allele). We show that mice with the FloxNeo allele exhibit differential VAChT expression in distinct neuronal populations. These mice show relatively intact VAChT expression in somatomotor cholinergic neurons, but pronounced decrease in other cholinergic neurons in the brain. VAChT mutant mice present preserved neuromuscular function, but altered brain cholinergic function and are hyperactive. Genetic removal of the resistance cassette rescues VAChT expression and the hyperactivity phenotype. These results suggest that release of ACh in the brain is normally required to “turn down” neuronal circuits controlling locomotion

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO
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