Adsorption cooler design, modeling, and dynamics and performance analyses

This paper presents an adsorption cooler (AC) driven by the surplus heat of a solar thermal domestic hot water system to provide cooling to residential buildings. A cylindrical tube adsorber using granular silica gel as adsorbent and water as adsorbate is considered. The AC is modelled using a two-dimensional distributed parameter model that was implemented in previous adsorption heating and cooling studies. The performance coefficients of the resultant thermally driven colling system are obtained for a broad range of working conditions. The thermally driven AC has a coefficient of performance (COP) of 0.5 and a specific cooling power (SCP) of 44 W.kg--1, considering condenser, evaporator, and regeneration temperatures of 15 oC, 18 oC, and 70 oC, respectively. Moreover, results show that the AC can be used for refrigeration purposes at temperatures as low as 2 oC, and that it can also operate during hotter days under temperatures of 42 oC.This work was supported by the grant SFRH/BD/145124/2019 and the projects UIDB/00481/2020 and UIDP/00481/2020 - FCT - Fundação para a Ciência e a Tecnologia; and CENTRO-01-0145-FEDER-022083 - Centro Portugal Regional Operational Programme (Centro2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund. The present study was developed in the scope of the Smart Green Homes Project [POCI-01- 0247-FEDER- 007678], a co-promotion between Bosch Termotecnologia S.A. and the University of Aveiro. It is financed by Portugal 2020 under the Competitiveness and Internationalization Operational Program, and by the European Regional Development Fund

Multidimensional continued fractions, dynamical renormalization and KAM theory

The disadvantage of `traditional' multidimensional continued fraction algorithms is that it is not known whether they provide simultaneous rational approximations for generic vectors. Following ideas of Dani, Lagarias and Kleinbock-Margulis we describe a simple algorithm based on the dynamics of flows on the homogeneous space SL(2,Z)\SL(2,R) (the space of lattices of covolume one) that indeed yields best possible approximations to any irrational vector. The algorithm is ideally suited for a number of dynamical applications that involve small divisor problems. We explicitely construct renormalization schemes for (a) the linearization of vector fields on tori of arbitrary dimension and (b) the construction of invariant tori for Hamiltonian systems.Comment: 51 page

Multiple giant resonances in nuclei: their excitation and decay

The excitation of multiphonon giant resonances with heavy ions is discussed. The conventional theory, based on the use of the virtual photon number method in conjunction with the harmonic model is presented and its shortcomings are discussed. The recently developed model that invoke the Brink-Axel mechanism as an important contribution to the cross-section is discussed and compared to the conventional, harmonic model. The decay properties of these multiple giant resonances are also discussed within the same coherent + fluctuation model in conjunction with the hybrid decay model. It is demonstrated that the Brink-Axel mechanism enhances the direct decay of the states, as data seem to require. Comparison of our model with other recent theoretical works is presented.Comment: 12 pages, four figures, two tables. Invited talk at the International Conference on Collective Motion in Nuclei Under Extreme Conditions (COMEX1), Paris, France, 10-13 June 200

Tuning the bioactivity of tensioactive deoxy glycosides to structure: antibacterial activity versus selective cholinesterase inhibition rationalized by molecular docking

New octyl/dodecyl 2,6-dideoxy-D-arabino-hexopyranosides have been synthesized by a simple but efficient methodology based on the reaction of glycals with alcohols catalysed by triphenylphosphane hydrobromide, deprotection, regioselective tosylation and reduction. Their surface-active properties were evaluated in terms of adsorption and aggregation parameters and compared with those of 2-deoxy-D-glycosides and 2,6-dideoxy-L-glycosides. Deoxygenation at the 6-position led to a decrease in the critical micelle concentration, and an increase in the adsorption efficiency (pC20) promoting aggregation more efficiently than adsorption. With regard to the antibacterial activity, dodecyl 2,6-dideoxy-α-L-arabino-hexopyranoside was the most active compound towards Bacillus anthracis (MIC 25 μM), whereas its enantiomer exhibited a MIC value of 50 μM. Both 2,6-dideoxy glycosides were active towards Bacillus cereus, Bacillus subtilis, Enterococcus faecalis and Listeria monocytogenes. In contrast, none of the 2-deoxy glycosides was significantly active. These results and the data on surface activity suggest that aggregation is a key issue for antimicrobial activity. Beyond infection, Alzheimer’s disease also threatens elderly populations. In the search for butyrylcholinesterase (BChE) selective inhibition, 2- deoxy glycosides were screened in vitro by using Ellman’s assay. Octyl 2-deoxy-α-D-glycoside was found to be a BChE selective inhibitor promoting competitive inhibition. Docking studies supported these results as they pinpoint the importance of the primary OH group in stabilizing the BChE inhibitor complex. A size-exclusion mechanism for inhibition has been proposed based on the fact that acetylcholinesterase (AChE) exhibits several bulky residues that hinder access to the active-site cavity. This work shows how the deoxygenation pattern, configuration and functionality of the anomeric centre can tune physical and surface properties as well as the bioactivity of these multifunctional and stereochemically rich molecules.FEDER e FCTinfo:eu-repo/semantics/publishedVersio

Quasi Free 238U (e,e'f)-Cross Section in Macroscopic-Microscopic Approach

We present the result of a theoretical study of inclusive quasi free electrofission of $^{238}$U. The off-shell $$cross sections for the quasi free reaction stage have been calculated within the Plane Wave Impulse Approximation (PWIA), using a Macroscopic -Microscopic description of the proton and neutron single particle momentum distributions. Electron wave function distortion corrections were included using the effective momentum approximation, and the Final State Interaction (FSI) effects were calculated using an optical potential. The fissility for the proton single hole excited states of the residual nucleus $^{237}$Pa was calculated both without and with contributions of the pre-equilibrium emission of the particles. The fissility for $^{237,238}U$ residual nuclei was calculated within the compound nucleus model. The $(e,e^{\prime}f)-$cross sections thus obtained were compared with available experimental data.Comment: 26 pages, 7 figure

Análise retrospectiva do resultado do tratamento com iodo radioativo em 120 pacientes tirotóxicos por doença de Basedow-graves

We studied retrospectively the outcome of radioactive iodine therapy (RAI) in 120 thyrotoxic patients with Graves' disease (96 F/ 24 M) who were primarily treated with anti-thyroid drugs (ATD). The decision to use RAI was due either to relapse after ATD-induced remission, lack of compliance on ATD, goiter larger than 60g, old age or association with severe diseases. ATD were discontinued one week before RAI administration, calculated by the formula: glandular volume (g) vs. effective radiation (80 mCi/g of tissue) divided by 24h thyroid uptake (%). We reexamined the patients for 48 months after RAI. Medians of age, goiter size and 24h thyroid uptake were 34y (17-69), 54.5g (20-210) and 73% (21-99), respectively. After RAI, patients became gradually hypothyroid on a rate of 15%/ 6mo until the first 18mo, followed by a rate of 2-5%/ 6mo until the end of 48mo. The number of patients in thyrotoxicosis decreased continuously, being 52.2% 6mo after RAI, 25% after 18mo and 6.7% after 48mo; at the end of the study 8 patients were still thyrotoxic. The total of patients without thyrotoxicosis at the end of observation, that is, the sum of those in euthyroidism and hypothyroidism on T4 therapy (cure of thyrotoxicosis) reached 46.8% in 6mo, 63.3% in 12mo, 81.7% in 24mo, 87.5% in 36mo and 93.3% in 48mo. Transient hypothyroidism, that is, elevation of TSH higher than 4.5 mU/L until 12mo after RAI, followed by normalization of TSH was found in 7.5% of patients. The following correlations were found in this study: a) initial T3 values and absence of cure of thyroxicosis (p=0.2); b) total RAI doses in relation to time for cure of thyrotoxicosis (p=0.01); c) dose of 131l/thyroid volume in relation to time for cure of thyrotoxicosis (p=0.02). Adverse effects included exarcebation of thyrotoxicosis in 3 patients and pain in the anterior cervical area in one, all reversible and of short duration. Two patients became pregnant after RAI but both gestations and their outcomes were normal.Estudamos retrospectivamente 120 pacientes (96 F/ 24 M) portadores de tirotoxicose por doença de Basedow-Graves submetidos à terapia com iodo radioativo (131I), que receberam inicialmente, para compensação da moléstia, drogas anti-tiroidianas (DAT). A indicação terapêutica posterior de radioiodo deveu-se a uma das seguintes condições clínicas: recidiva após compensação com DAT, falta de compensação devida à baixa aderência às DAT, bócios maiores que 60g, idade avançada ou doença grave associada. As DAT foram suspensas uma semana antes da administração da dose de 131I, calculada pela fórmula: volume glandular (em g) X radiação efetiva (80 mCi/g de tecido) ¸ captação tiroideana de 24hs. Reavaliamos os pacientes por até 48 meses após a radioiodoterapia. As medianas iniciais de idade, bócio e captação tiroideana de 24hs dos 120 pacientes foram, respectivamente, 34 anos (17-69), 54,5g (20-210) e 73% (21-99). A evolução para hipotiroidismo foi gradual, com 15% dos pacientes a cada 6m até o 18º mês, seguidos de 2 a 5% dos pacientes a cada 6m até o 48º mês. O número de pacientes em tirotoxicose decresceu continuamente, representando 52,2% do total inicial após 6m, 25% após 18m e 6,7% após 48m. Ao final, 8 pacientes continuaram em tirotoxicose. O número de pacientes sem tirotoxicose após o tratamento com 131I, ou seja a soma daqueles em eutiroidismo com aqueles em hipotiroidismo com reposição com T4 (denominada por nós de cura da tirotoxicose), alcançou 46,8% dos pacientes em óm, 63,3% em 12m, 81,7% em 24m, 87,5% em 36m e 93,3% em 48m. O número de pacientes que apresentaram hipotiroidismo transitório, ou seja, elevação do TSH acima de 4,5 mU/L até 12m após a dose de 131I, com normalização posterior, foi 7,5%. Correlacionaram-se positivamente: a) valores iniciais de T3 e ausência de evolução para a cura da tirotoxicose (p=0,02); b) doses totais de 131I administradas, únicas ou múltiplas, em relação ao tempo de cura da tirotoxicose (p=0,01); c) dose de 131 l/volume glandular em relação ao tempo de cura da tirotoxicose (p=0,02). Os efeitos adversos incluíram exacerbação da tirotoxicose em 3 pacientes e dor na região cervical anterior em um, com reversão dos quadros em todos. Outras duas pacientes engravidaram após o dose terapêutica de 131I para a tirotoxicose e tiveram gestações sem intercorrência e recém-nascidos normais.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MedicinaUNIFESP, EPM, Depto. de MedicinaSciEL

Effect of anion type in the performance of ionic liquid/poly(vinylidene fluoride) electromechanical actuators

Low voltage actuators based on poly(vinylidene fluoride)(PVDF)with 10, 25 and 40 % 1-hexyl-3-methylimidazolium chloride ([C6mim][Cl])and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][NTf2]) are prepared by solvent casting in order to evaluate the effect of anion size in the bending properties. Independently of the ionic liquid type and content, its presence leads to the crystallization of PVDF in the -phase. The addition of ionic liquid into the polymer matrix decreases significantly its degree of crystallinity and the elastic modulus. It is also confirmed the good miscibility between PVDF and IL,determinedby the interaction of the CF2groups from the PVDF chains with the imidazolium ring in the ionic liquid (IL). The AC conductivity of the composites depends both on the amount of ionic liquid content and anion size. The bending movement of the IL/PVDF composites is correlated to theirdegree of crystallinity, mechanical properties and ionic conductivity value and the best value of bending response (0.53 %) being found for IL/PVDF composite with40 wt% of [C6mim][Cl] at an applied voltage of 10 volts square signal.The authors thank the FCT-Fundação para a Ciência e Tecnologia-for financial support in the framework of the Strategic Funding UID/FIS/04650/2013, projects PTDC/EEI-SII/5582/2014 and PTDC/CTM-ENE/5387/2014,and grants SFRH/BD/90215/2012 (J.C.D.), SFRH/BPD/112547/2015 (C.M.C.). The authors thank Solvay for kindly supplying the high quality materials. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged.The authorsexpress their gratitude to the Ministry of the Higher Education and Scientific Research of Tunisiafor a research fellowship

Reproductive performance of sows inseminated with semen doses stored for up to seven days in long-term extender in a field condition

This study aimed to evaluate the reproductive performance of sows inseminated with semen doses preserved at 15-18 °C for up to seven days in long-term extender (Duragen®). Parity one (PO1) to PO7 sows were randomly assigned to the following groups: AI1-3 (n=190), insemination with semen doses stored between one and three days; and AI5-7 (n=124), insemination with semen doses stored between five and seven days. Sows were submitted to estrus detection twice a day. Post-cervical insemination according to weaning-to-estrus interval was performed. The farrowing rate (FR) did not differ between the groups (AI1-3=83.2%; AI5-7=82.2%; p>0.05) nor did the total number of piglets born (TPB; AI1-3=14.2±0.3; AI5-7=14.5±0.3; p>0.05). Considering the semen dose most likely responsible for fertilization according to its storage time (1, 2-3, 5, and 6-7 days), the FR (72.7%, 87.8%, 85.7%, and 79%, respectively) and TPB (14.4, 14.0, 14.9, and 13.5, respectively) were similar among the groups (p>0.05). In conclusion, the use of semen doses extended with long-term extender stored for up to seven days did not impair the reproductive performance of sows. Therefore, it’s using could optimize production efficiency and logistics of semen dose deliveries to sow farms