Advances in the self-consistent Green's function approach to finite nuclei are discussed, including the implementation of three-nucleon forces and the extension to the Gorkov formalism. We report ...results on binding energies in the nitrogen and fluorine isotopic chains, as well as spectral functions of 22O. The application to medium-mass open-shell systems is illustrated by separation energy spectra of two argon isotopes, which are compared to one-neutron removal experiments.
As ab-initio calculations of atomic nuclei enter the A=40-100 mass range, a great challenge is how to approach the vast majority of open-shell (degenerate) isotopes. We add realistic three-nucleon ...interactions to the state of the art many-body Green's function theory of closed-shells, and find that physics of neutron driplines is reproduced with very good quality. Further, we introduce the Gorkov formalism to extend ab-initio theory to semi-magic, fully open-shell, isotopes. Proof-of-principle calculations for Ca-44 and Ni-74 confirm that this approach is indeed feasible. Combining these two advances (open-shells and three-nucleon interactions) requires longer, technical, work but it is otherwise within reach.
The recently confirmed neutron-shell closure at N = 32 has been investigated for the first time below the magic proton number Z = 20 with mass measurements of the exotic isotopes 52,53K, the latter ...being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly lower than for 52Ca, highlighting the doubly-magic nature of this nuclide. Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively the observed shell effect.
•Recuperative ORC (RORC) presents a higher efficiency (+20 %) and power (+18 %) than ORC.•RORC works with a lower mass flow rate than ORC for a given evaporating temperature.•RORC needs a lower heat ...input thus increasing the operating time in absence of solar radiation.•The higher operating time involves a higher yearly electricity energy production (+37 %).•Hot water and coolant temperature play the most important effect on RORC performance.
Organic Rankine Cycle -based microcogeneration systems that exploit solar sources to generate electricity and domestic hot water simultaneously are promising solutions for reducing CO2 emissions in the residential energy-intensive sector. Such systems can be assisted by thermal energy storage reservoirs in which water is heated by solar energy and cooled by the direct use of thermal energy for domestic hot water production and acting as heat source of the power plant. An interesting plant layout optimisation involves the adoption of a recuperative heat exchanger to preheat the working fluid before it enters the heat recovery vapour generator, which is fed with the same working fluid leaving the expander. Despite the positive effect of recuperative heat exchanger adoption on the efficiency of the entire plant, the impact on electrical energy production at this microscale is not straightforward to assess as the heat source is represented by the water inside the reservoir and it is not a continuous high- or medium-temperature stream. The lack of experimental analyses in the literature on these applications makes this a debatable question.
Thus, to fill this gap and quantitatively assess the benefits introduced by the adoption of a recuperative stage, a wide experimental comparison between recuperative and not-recuperative Organic Rankine Cycle-based power unit layout was performed. To support the experimental analysis, a comprehensive theoretical model of the Organic Rankine Cycle-based plant was developed and validated against experimental data.
The experimental campaign demonstrated that the recuperative Organic Rankine Cycle-based unit required a lower working fluid flow rate for a given expander inlet temperature and pressure ratio. Consequently, a higher electrical power can be produced, requiring lower thermal power from a heat source. The reduction in the thermal power absorbed from the heat source, produced by a higher temperature incoming working fluid entering the Heat Recovery Vapor Generator, had a positive effect, allowing a longer-in-time working condition with a higher conversion efficiency intrinsically produced by the recuperative heat exchanger. Considering the annual electricity consumption of 2700 kWh of a family living in a city in central Italy, the contribution given by the recuperative Organic Rankine Cycle plant operating with a reservoir fed by 15 m2 of flat solar panels was 330 kWh, whereas without the recuperative stage, the production was 240 kWh. The cost of electricity saved justified the adoption of a recuperative heat exchanger.
En el ámbito de la concreción y la materialidad, el dinero siempre ha sido un valor indiscutible que es exponente y dígito de control de la política y la religión y de las economías consiguientes; ...sin mencionar el aspecto financiero y mercantil específico. Esta contribución ofrece una visión panorámica sobre la estrecha relación entre la política del papado y la inversión de dinero en la época de las cruzadas y la yihad. Se verá claramente que la inversión absolutamente más importante se destinó al rearme y a las empresas de la «guerra santa».Como alternativa a la propaganda y a la política del rearme y de las cruzadas, hubo varias voces que gritaban Deus non vult. Entre ellas había un proyecto concreto alternativo al servicio militar que proponía, como una cruz roja internacional, el servicio humanitario para redimir a los prisioneros cristianos y musulmanes de las «guerras santas». Esta labor necesitaba mucho dinero. Los redentores trinitarios toman como norma de vida la división aritmética de todos los bienes en tres partes iguales: una para el propio sustento, otra para la hospitalidad de los pobres y otra para la redención de los cautivos.Se trata de un caso único a lo largo de la historia en la distribución de los bienes eclesiásticos, a pesar de las reglas precisas que a partir de la intuición de Ambrosio de Milán se codifican en el Decretum Gratiani.
En el ámbito de la concreción y la materialidad, el dinero siempre ha sido un valor indiscutible que es exponente y dígito de control de la política y la religión y de las economías consiguientes; ...sin mencionar el aspecto financiero y mercantil específico. Esta contribución ofrece una visión panorámica sobre la estrecha relación entre la política del papado y la inversión de dinero en la época de las cruzadas y la yihad. Se verá claramente que la inversión absolutamente más importante se destinó al rearme y a las empresas de la «guerra santa». Como alternativa a la propaganda y a la política del rearme y de las cruzadas, hubo varias voces que gritaban Deus non vult. Entre ellas había un proyecto concreto alternativo al servicio militar que proponía, como una cruz roja internacional, el servicio humanitario para redimir a los prisioneros cristianos y musulmanes de las «guerras santas». Esta labor necesitaba mucho dinero. Los redentores trinitarios toman como norma de vida la división aritmética de todos los bienes en tres partes iguales: una para el propio sustento, otra para la hospitalidad de los pobres y otra para la redención de los cautivos. Se trata de un caso único a lo largo de la historia en la distribución de los bienes eclesiásticos, a pesar de las reglas precisas que a partir de la intuición de Ambrosio de Milán se codifican en el Decretum Gratiani.
Another theme that deserves to be developed is that of poverty understood as deprivation and / or as an investment, voluntary begging for alms together with the organization of work and the ...distribution of the relative income of the western monastic world in its various forms. Among the most conspicuous investments of money by the Latin church and the papacy there are ample pages to explore around the finances of the papal state, the management of tithes (rationes decimarum) with policies that directed substantial cash flows to set up corsair activities and military expeditions by land or by sea. ...we need to achieve a deeper understanding of the history of the monies accumulated through voluntary donations, the banks of the church in competition with the banks of the kingdom or the city, and the laws that regulated the market, even that, obviously, developed with others', whether Jews or Saracens, a practice that moved from excommunications to collaboration: it started by being tolerated and then allowed and even encouraged. 2 His theory and practice are of such immense value as to set an example that has spanned the centuries, and even established a juridical norm that would be in force in our period and far beyond it, through the Decretum Gratiani. ...Ambrose's approach became the norm; it was incorporated into Justinian's Decretum3 and subsequently into Gratian's Decretum4.
The paper presents the modeling of a fin-cooled photovoltaic (PV) module, under real operating conditions. A full reconstruction of both the thermal behavior – transient energy balance, loss to the ...environment and module temperature - and the electrical dynamics for the system allows the efficiency gain assessment, associated with an increased heat exchange with ambient air. Various layouts are considered, in terms of fins mass and its effects on the heat capacity, fins amount and fins geometry. The model accounts for the PV module performances dependence on the (i) operating temperature and (ii) solar irradiance and integrates a section for continuous update of I-V PV characteristics, based on a standard five parameters model and the one-diode approximation. The merge between limit performances - as provided by the manufacturer – and evidences from an extensive experimental campaign for the in-field module characterization, allow a detailed reconstruction of the electric power associated with the module operation and prevent any bias in the model output. The potential of fins in module temperature control and electric efficiency enhancement is assessed and confirms the appeal of such a layout with respect to more consolidated cooling techniques.
•Finned PV module electrical performance and heat exchanges assessment in operation.•I-V curves reconstruction and temperature dependence through a five parameter model.•Five parameter model calibration based on data from experimental campaign.•System optimum design for maximum PV module temperature reduction during operation.•Electric conversion efficiency gain evaluation per achieved temperature reduction.
The Compressed Air Sector accounts for a mean 10% worldwide electricity consumption, which ensures about its importance, when energy saving and CO2 emissions reduction are in question. Since the ...compressors alone account for 15% overall industry electricity consumption, it appears vital to pay attention to machine performances.
The paper presents an overview of present compressor technology and focuses on saving directions for screw and sliding vanes machines, according to data provided by the Compressed Air and Gas Institute and PNEUROP. Data were processed to obtain consistency with fixed reference pressures and organized as a function of main operating parameters. Each sub-term, contributing to the overall efficiency (adiabatic, volumetric, mechanical, electric, organic), was considered separately: the analysis showed that the thermodynamic improvement during compression achievable by splitting the compression in two stages, with a lower compression ratio, opens the way to significantly reduce the energy specific consumption.
•Compressors technology overview in industrial compressed air systems.•Market compressors efficiency baseline definition.•Energy breakdown and evaluation of main efficiency terms.•Assessment of air cooling-related energy saving potential.•Energy specific consumption reduction through dual stage compression.
