Performance evaluation of transcritical CO2 desiccant heat pumps for electric vehicles

Transcritical CO2 heat pump systems are eco-friendly and have excellent heating performance, which makes them suitable for electric vehicles. The recirculation mode can save energy but requires a dehumidification function to ensure driving safety. Therefore, this paper proposes a transcritical CO2 desiccant heat pump, which differs from the typical transcritical CO2 heat pump system by incorporating an indoor evaporator and a full-pass throttle valve. The flow area of the full-pass throttle valve can be adjusted to obtain the appropriate dehumidification rate. In addition, this study suggested using the desiccant heat pump coefficient of performance (DHCOP) to evaluate the overall energy efficiency of the heat pump system. We have investigated the dehumidification rate and optimal discharge pressure under different operating conditions. The results show that even under the harsh operating conditions at -10 °C, the HDCOP of the transcritical CO2 desiccant heat pump can still exceed 2.1, and reach 3.12 at a moderate condition of Ta=5 °C. The transcritical CO2 heat pump desiccant system demonstrates significant energy-saving potential

Parasitic phases at the origin of magnetic moment in BiFeO3 thin films grown by low deposition rate RF sputtering

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQA series of epitaxial BiFeO3 thin films has been grown under high partial pressure in a pure O-2 atmosphere, which leads to a low deposition rate. The samples grown under these conditions have presented an evolution of the quality of the epitaxy as the deposition temperature increases, however, spurious beta-Bi2O3 and supertetragonal BiFeO3 phases are present in the films grown at higher temperatures. The presence of gamma-Fe2O3 is reported in one growing condition, and has been attributed to the origin of hysteretic ferromagnetic behavior. A second kind of magnetism, with higher magnetic moment and anhysteretic behaviour, is attributed to the presence of mixed phases of BiFeO3.1221215FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ2012/18397-12012/51198-2309354/2015-3This work was supported by FAPESP (Project No. 2012/51198-2). Some of the XRD measurements were performed at the XRD2 beamline of the LNLS/CNPEM under Project Nos. 20150162 and 20160908. The authors thank the LNNano/CNPEM for XRD/XRR, AFM and sputtering facilities, the LIEC/UFSCar for the SQUID measurements, and M. M. Soares for important discussions regarding the structural characterization. P.S. thanks FAPESP for financial support (Project No. 2012/18397-1). J.C.C. acknowledges support from CNPq (Project No. 309354/2015-3)

Insight into intramolecular chemical structure modifications by on-surface reaction using photoemission tomography

The sensitivity of photoemission tomography (PT) to directly probe single molecule on-surface intramolecular reactions will be shown here. PT application in the study of molecules possessing peripheral ligands and structural flexibility is tested on the temperature-induced dehydrogenation intramolecular reaction on Ag(100), leading from CoOEP to the final product CoTBP. Along with the ring-closure reaction, the electronic occupancy and energy level alignment of the frontier orbitals, as well as the oxidation state of the metal ion, are elucidated for both the CoOEP and CoTBP systems

Características de carcaça e do couro de bovinos precoces e superprecoces.

Objetivou-se avaliar o efeito do sistema de produção sobre características produtivas e do couro de bovinos cruzados precoces e superprecoces. Foram utilizados 36 animais, sendo 16 provenientes do sistema superprecoce (10 machos castrados e seis fêmeas), terminados em confinamento e 20 animais do sistema precoce (10 machos castrados e 10 fêmeas), terminados em pastagens, recebendo suplementação protéico energética (1 kg/dia/animal). Após o abate os couros foram processados até a etapa de couro semi-acabado, onde foram retiradas as amostras da região do dorsolombar para os ensaios físico-mecânicos de tração e rasgamento. Houve efeito do sistema de produção para ganho de peso total (GPT), ganho médio diário (GMD), área de olho de lombo (AOL), espessura de gordura subcutânea (EGS), marmoreio, peso da pele ao abate (PPe1) e perdas com a padronização, com menores médias para animais precoces. As perdas apresentadas pelas fêmeas foram 14,48 e 6,88 kg, e para os machos castrados 9,32 e 4,84 kg, respectivamente para superprecoces e precoces. As médias de PA, peso da pele padronizada e área do couro Wet-blue dos machos castrados foram 473,60 kg, 40,60 kg e 4,52 m², respectivamente, para superprecoces e 462,83 kg, 29,77 kg e 4,31 m², respectivamente, para precoces. Não houve efeito de sexo e de sistema de produção para as características avaliadas nos ensaios físicos mecânicos no couro de bovinos precoces e superprecoces

Mechanism of localization of the magnetization reversal in 3 nm wide Co nanowires

The mechanism of magnetization reversal has been studied in a model system of self-assembled cobalt nanowires with a 3 nm diameter. The structure, orientation and size of grains within the nanowires could be determined by high resolution transmission electron microscopy. The magnetic properties were probed using static and dynamic magnetization measurements. Micromagnetic modeling based on the structural analysis allows us to correlate the structure and the magnetic behavior of the wires, revealing competition between shape anisotropy, magnetocrystalline anisotropy and exchange in the localized reversal within Co hcp oriented grains. These results provide direct experimental evidence of the link between anisotropy fluctuations and reversal localization in nanowires.Fil: Vidal, F.. Universite de Paris Vi. Institut Des Nanosciences de Paris; FranciaFil: Zheng, Y.. Universite de Paris Vi. Institut Des Nanosciences de Paris; FranciaFil: Schio, P.. Universidade Federal Do Sao Carlos; Brasil. Universite de Paris Vi. Institut Des Nanosciences de Paris; FranciaFil: Bonilla, F. J.. Universite de Paris Vi. Institut Des Nanosciences de Paris; FranciaFil: Barturen, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universite de Paris Vi. Institut Des Nanosciences de Paris; Francia. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Milano, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universite de Paris Vi. Institut Des Nanosciences de Paris; Francia. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Universidad Nacional de Cuyo; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Demaille, D.. Universite de Paris Vi. Institut Des Nanosciences de Paris; FranciaFil: Fonda, E.. L’Orme des Merisiers Saint-Aubin. Synchrotron Soleil; FranciaFil: de Oliveira, A. J. A.. Universidade Federal Do Sao Carlos; BrasilFil: Etgens, V. H.. Universite de Paris Vi. Institut Des Nanosciences de Paris; Francia. Fédération Lavoisier Franklin; Franci

Photoionization Dynamics of the Tetraoxo Complexes OsO4 and RuO4

The photoionization dynamics of OsO4 and RuO4, chosen as model systems of small-size mononuclear heavy-metal complexes, has been theoretically studied by the time-dependent density functional theory (TDDFT). Accurate experimental measurements of photoionization dynamics as a benchmarking test for the theory are reported for the photoelectron asymmetry parameters of outer valence ionizations of OsO4, measured in the 17-90 eV photon energy range. The theoretical results are in good agreement with the available experimental data. The observed dynamical behavior of partial cross sections and asymmetry parameters has been related to both the coupling to the continuum of discrete excited states, giving strong modulations in the photon energy dependency, and the atomic composition of the initial ionized states, which determines the rate of decay of ionization probability for increasing excitation energies. Overall, an extensive analysis of the photoionization dynamics for valence and core orbitals is presented, showing good agreement with all the available experimental data. This provides confidence for the validity of the TDDFT approach in describing photoionization of heavy transition element compounds, with the perspective of being used for larger systems. Further experimental work is suggested for RuO4 to gather evidence of the sensitivity of the theoretical method to the nature of the metal atom