Multiobjective Optimization of Cement-Based Panels Enhanced with Microencapsulated Phase Change Materials for Building Energy Applications

Thermal energy storage using phase change materials (PCMs) is a promising technology for improving the thermal performance of buildings and reducing their energy consumption. However, the effectiveness of passive PCMs in buildings depends on their optimal design regarding the building typology and typical climate conditions. Within this context, the present contribution introduces a novel multiobjective computational method to optimize the thermophysical properties of cementitious building panels enhanced with a microencapsulated PCM (MPCM). To achieve this, a parametric model for PCM-based cementitious composites is developed in EnergyPlus, considering as design variables the melting temperature of PCMs and the thickness and thermal conductivity of the panel. A multiobjective genetic algorithm is dynamically coupled with the building energy model to find the best trade-off between annual heating and cooling loads. The optimization results obtained for a case study building in Sofia (Bulgaria-EU) reveal that the annual heating and cooling loads have contradictory performances regarding the thermophysical properties studied. A thick MPCM-enhanced panel with a melting temperature of 22 (Formula presented.) C is needed to reduce the heating loads, while a thin panel with a melting temperature of 27 (Formula presented.) C is required to mitigate the cooling loads. Using these designs, the annual heating and cooling loads decrease by 23% and 3%, respectively. Moreover, up to 12.4% cooling load reduction is reached if the thermal conductivity of the panels is increased. Therefore, it is also concluded that the thermal conductivity of the cement-based panels can significantly influence the effectiveness of MPCMs in buildings

EVALUATION OF THERMAL AND MECHANICAL PROPERTIES OF DEMONSTRATION WALL UTILIZING PHASE CHANGE CEMENTITIOUS MATERIALS

International project PoroPCM involves partners from Germany, Czech Republic, Spain and Japan with the objective to develop new multifunctional Phase Change Materials modified porous cementitious nanocomposite (PoroPCM). Such material can be utilized for storing heat energy in the insulation layer of buildings compared to commonly used insulation materials since the phase change increases heat capacity. This enhanced feature reduces the amount of energy necessary for running the heating/cooling system. For the testing of the newly developed phase change cementitious composite a demonstration wall will be developed and tested for its thermal as well as mechanical performance. The topic of the paper is the description of the properties of the new phase change cementitious nanocomposite. The main emphasis of the paper is the description of the demonstration wall behaviour under typical environmental conditions. The wall design is supported by numerical simulation of the wall physical parameters. The numerical modelling involves the definition of suitable numerical models for the simulation of the thermal properties of the new phase change nanocomposite. The numerical model is then used to demonstrate the performance of the wall layer design. The presented pilot results show efficiency increase of the insulation material in the range 15–70%. Also modelling of wind resistance of the layered structure is included. The developed wall design and PoroPCM material will be tested and verified by a large scale test in the final year of the project

Particle decay branching ratios for states of astrophysical importance in 19Ne

We have measured proton and alpha-particle branching ratios of excited states in 19Ne formed using the 19F(3He,t) reaction at a beam energy of 25 MeV. These ratios have a large impact on the astrophysical reaction rates of 15O(alpha,gamma), 18F(p,gamma) and 18F(p,alpha), which are of interest in understanding energy generation in x-ray bursts and in interpreting anticipated gamma-ray observations of novae. We detect decay protons and alpha-particles using a silicon detector array in coincidence with tritons measured in the focal plane detector of our Enge split-pole spectrograph. The silicon array consists of five strip detectors of the type used in the Louvain-Edinburgh Detector Array, subtending angles from 130 degrees to 165 degrees with approximately 14% lab efficiency. The correlation angular distributions give additional confidence in some prior spin-parity assignments that were based on gamma branchings. We measure Gamma_p/Gamma=0.387+-0.016 for the 665 keV proton resonance, which agrees well with the direct measurement of Bardayan et al.Comment: 5 pages, 2 figures, 3 tables. Prepared using RevTex 4 and BibTex. Further minor revisions, incl. fig. 1 font size increase, 1 table removal, and minor changes to the tex

Optimizing Inventory in a Multi-Echelon Multi-Item Supply Chain with Time-Based Customer Service Level Agreements

Optimizing Inventory in a Multi-Echelon Multi-Item Supply Chain with Time-Based Customer Service Level Agreement

Estimating Fiscal Multipliers: News From A Non-linear World

We estimate non-linear VARs to assess to what extent fiscal spending multipliers are countercyclical in the US. We deal with the issue of non-fundamentalness due to fiscal foresight by appealing to sums of revisions of expectations of fiscal expenditures. This measure of anticipated fiscal shocks is shown to carry valuable information about future dynamics of public spending. Results based on generalised impulse responses suggest that fiscal spending multipliers in recessions are greater than one, but not statistically larger than those in expansions. However, non-linearities arise when focusing on 'extreme' events, that is, deep recessions versus strong expansionary periods

Heavy Metal Concentrations in Dairy Products from Sheep Milk Collected in Two Regions of Southern Italy

The aim of this work was to detect the concentrations of some heavy metals in milk collected from ewes in 8 farms located in Calabria and Campania and to evaluate to what extent these metals may be present in dairy products for human consumption. The analysis of chromium, cadmium, lead and mercury was performed in a atomic absorption spectrophotometer equipped with a graphite furnace. The determination of Hg content in dry samples was carried out by means of an automatic Mercury analyser. Chromium was the metal detected at highest levels in milk and lead was highest in fresh, mature cheese and in ricotta. In Italy, human consumption of sheep milk is very limited and addressed to milk products. In our study the levels of some metals were higher than those reported in literature. However, the results indicate that sheep milk and milk products from the two regions of Italy investigated in this study are safe for consumers

Sidechain Diversification of Grandifloracin Allows Identification of Analogues with Enhanced Anti-Austerity Activity against Human PANC-1 Pancreatic Cancer Cells

© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. The natural product (+)-grandifloracin is a potent “anti-austerity” agent, able to suppress the ability of various pancreatic cancer cell lines to tolerate conditions of nutrient deprivation. Such anti-austerity agents represent a promising approach to cancer chemotherapy. Here we report the synthesis and biological evaluation of racemic analogues of grandifloracin bearing diverse sidechains, of which two show enhanced potency in comparison with the natural product. Additionally, several unexpected by-products containing modifications of the grandifloracin core were isolated, identified and similarly evaluated for biological activity.We thank EPSRC (DTP studentship to B.E.A.) and Cancer Research at Bath (CR@B) for funding. The biological investigation was supported by a grant from the Japanese Society for the Promotion of Science (JSPS Kakenhi #16 K08319) and the Kobayashi International Scholarship Foundation to S.A.Published versio

Suppressed-scattering spectral windows for radiative cooling applications

The scattering of light by resonant nanoparticles is a key process for enhancing the solar reflectance in daylight radiative cooling. Here, we investigate the impact of material dispersion on the scattering performance of popular nanoparticles for radiative cooling applications. We show that, due to material dispersion, nanoparticles with a qualitatively similar response at visible frequencies exhibit fundamentally different scattering properties at infrared frequencies. It is found that dispersive nanoparticles exhibit suppressed-scattering windows, allowing for selective thermal emission within a highly reflective sample. The existence of suppressed-scattering windows solely depends on material dispersion, and they appear pinned to the same wavelength even in random composite materials and periodic metasurfaces. Finally, we investigate calcium-silicate-hydrate (CSH), the main phase of concrete, as an example of a dispersive host, illustrating that the co-design of nanoparticles and host allows for tuning of the suppressed-scattering windows. Our results indicate that controlled nanoporosities would enable concrete with daylight passive radiative cooling capabilities