Effect of photovoltaic installation power and façade glazing ratio on the energy performance of a nursery building

PurposeThe aim of the research is to determine the influence of photovoltaic (PV) installation and the share of façade glazing on the energy profile of nursery buildings in the Baltic Sea region, as well as defining the most favorable configuration in terms of energy efficiency.Design/methodology/approachThe article provides comparative calculations of energy performance indicators (Ep, Ed, Eu) and CO2 emissions (mCO2) made for the defined model of the nursery. It includes calculations concerning energy performance of the building, depending on its PV power (0–60 kWp), PV efficiency (100 and 85%) and façade glazing ratio (GR = 25%, 50% and 75%).FindingsThe results of the research indicate that an increase in the PV power exerts proportional impact on the reduction of the Ep and Ed indicators, as well as on the CO2 emissions. Only low GR values (25%) reduce the Eu indicator significantly. Decrease in high range of GR values (over 50%) does not provide proportional effects. In the variant: 60 kWp (100% efficiency) with GR = 25%, the biggest share (99.5%) of RES was obtained. This proves that the concept of energy independent nursery buildings is feasible and reasonable in the examined location.Practical implicationsDesigning buildings towards environmental neutrality requires laborious pre-design conceptual work before developing the right solutions. The set of results of the relationship between the variables of the building's envelope, energy performance indicators and the required involvement of active RES installations to achieve high energy performance of a building presented in the article is valuable. It allows for a preliminary decision of the direction of the design solutions selection in the design process of public utility buildings, such as nurseries. Thus, it may significantly shorten the pre-design analysis process for the location of the southern part of the Baltic Sea region.Originality/valueThe novelty of the paper relies on examining the dependences between PV power and façade glazing ratio in terms of their influence on energy profile of nursery buildings.

On boundary corrections of Lüscher-Weisz string

The potential and the density profile of the QCD flux-tube are investigated within the framework of the Luscher-Weisz (LW) string action with two boundary terms. The Numerical simulations involve 4D SU(3) Yang-Mills LGT at finite temperature. In general, we detect signatures of the two boundary terms considered in the LWstring action. Near the end of QCD Plateau, the LW string is yielding a static potential which is in a good agreement with the lattice data for source separations R ≥ 0.3 fm. However, at T/Tc = 0.9, the fit to the potential data improves with a good fit attained at R ≥ 0.7 fm. The mean-square width of the energy profile at T/Tc = 0.9 matches well the width of the LW string over distance scales R ≥ 0.5 fm.

Optimal cost and feasible design for grid-connected microgrid on campus area using the robust-intelligence method

In this paper, a robust optimization and sustainable investigation are undertaken to find a feasible design for a microgrid in a campus area at minimum cost. The campus microgrid needs to be optimized with further investigation, especially to reduce the cost while considering feasibility in ensuring the continuity of energy supply. A modified combination of genetic algorithm and particle swarm optimization (MGAPSO) is applied to minimize the cost while considering the feasibility of a grid-connected photovoltaic/battery/diesel system. Then, a sustainable energy-management system is also defined to analyse the characteristics of the microgrid. The optimization results show that the MGAPSO method produces a better solution with better convergence and lower costs than conventional methods. The MGAPSO optimization reduces the system cost by up to 11.99% compared with the conventional methods. In the rest of the paper, the components that have been optimized are adjusted in a realistic scheme to discuss the energy profile and allocation characteristics. Further investigation has shown that MGAPSO can optimize the campus microgrid to be self-sustained by enhancing renewable-energy utilization.

Aquaglyceroporin AQP7's affinity for its substrate glycerol

AQP7 is one of the four human aquaglyceroporins that facilitate glycerol transport across the cell membrane, a biophysical process that is essential in human physiology. Therefore, it is interesting to compute AQP7s affinity for its substrate (glycerol) with reasonable certainty to compare with the experimental data suggesting high affinity in contrast with most computational studies predicting low affinity. In this study aimed at computing the AQP7-glycerol affinity with high confidence, we implemented a direct computation of the affinity from unbiased equilibrium molecular dynamics (MD) simulations of three all-atom systems constituted with 0.16M, 4.32M, and 10.23M atoms, respectively. These three sets of simulations manifested a fundamental physics law that the intrinsic fluctuations of pressure in a system are inversely proportional to the system size (the number of atoms in it). These simulations showed that the computed values of glycerol-AQP7 affinity are dependent upon the system size (the inverse affinity estimations were, respectively, 47.3 mM, 1.6 mM, and 0.92 mM for the three model systems). In this, we obtained a lower bound for the AQP7-glycerol affinity (an upper bound for the dissociation constant). Namely, the AQP7-glycerol affinity is stronger than 1087/M (the dissociation constant is less than 0.92 mM). Additionally, we conducted hyper steered MD (hSMD) simulations to map out the Gibbs free-energy profile. From the free-energy profile, we produced an independent computation of the AQP7-glycerol dissociation constant being approximately 0.18 mM.

A Study of Compressibility, Compactability and Mucoadhesivity of Tableting Materials for Matrix Systems Based on Chitosan

The objective of the present research is to evaluate directly compressible chitosan-based tableting materials for the formulation of mucoadhesive matrix tablets intended for targeted drug release to distal segments of the GIT. The influence of sodium alginate, hypromellose, and silicified microcrystalline cellulose (P90) on compressibility, compactability and lubricant sensitivity ratio was tested. Furthermore, the rheological properties of the hydrated surface layer of the matrix tablets and the mucoadhesion to a mucin substrate were analysed. Compressibility was evaluated using the energy profile of the compression process, compactability by means of the tensile strength of tablets, and lubricant sensitivity ratio was calculated to assess the sensitivity to lubricant. Addition of P90 to chitosan improved compressibility, which is demonstrated by the increase in the energy of plastic deformation and the higher tensile strength of tablets. P90 also significantly reduced the high lubricant sensitivity of chitosan. Presence of retarding components led to a decrease in Emax. All tested matrix tablets revealed a good mucoadhesion without a negative effect of P90 content. The viscosity of a gel layer on the surface of matrix tablets containing hypromellose was higher compared to those with sodium alginate. This was not reflected in the adhesive strength of the tablets. The formulated tableting materials combining chitosan and P90 are a suitable matrix for incorporation of an active ingredient, whose delayed release in the intestine can be achieved by the functionality of the chitosan-sodium alginate complex.

Theoretical Study of Oxygen Atom Adsorption on A Polycyclic Aromatic Hydrocarbon Using Density-Functional Theory

Potential energy curves (PECs) and energy profiles of atomic O attack on coronene as a model for graphene/graphitic surface and interstellar reaction surface have been computed at the unrestricted B3LYP/cc-pVDZ level of theory to elaborate on atomic O attack mechanism and chemisorption on coronene. The PECs were generated by scanning the O atom distance to the closest carbon atom on "top" and "bridge" positions in the coronene, while fully relaxed geometries in the triplet state were investigated to gain the energy profile. We found that the most favorable geometry as the final product was the chemically bound O on the "bridge" site in the singlet state with an interaction energy of –29.2 kcal/mol. We recommended a plausible mechanism of atomic O attack and chemisorption reaction on coronene or generally graphitic surface starting from the non-interacting O atom and coronene systems into the chemically bound O atom on coronene.

Mechanism and Origin of Remote Stereocontrol in the Organocatalytic C(sp2)-H Alkylation using Nitroalkanes as Alkylating Agents

ABSTRACT: Experimental 13C kinetic isotope effects (KIEs) and DFT calculations are used to evaluate the mecha-nism and the origin of enantioselectivity in the C(sp2)‒H alkylative desymmetrization of cyclopentene-1,3-diones using nitroalkanes as the alkylating agent. An unusual combination of an inverse (~0.980) and a normal (~1.030) KIE is observed on the bond-forming carbon atoms of the cyclopentene-1,3-dione and nitroalkane, respectively. These data provide strong support for a mechanism involving reversible carbon-carbon bond-formation followed by rate- and enantioselectivity-determining nitro-group elimination. The theoretical free energy profile and predicted KIEs indicate that this elimination event occurs via an E1cB pathway. The origin of remote stereocontrol is evaluated by distortion-interaction and SAPT0 analyses of the enantiomeric E1cB transition states.