Developments in Coarse-Grain Modeling of Transient Heat-Flow in Buildings

The note reports on recent developments to the coarse-grain method (CGM) of modeling transient heat flow in buildings. CGM was originally developed as an alternative to conventional fine-grain modeling techniques [such as the finite-difference method (FDM) and finite-element method (FEM)] to increase simulation speed to a degree that facilitates three-dimensional modeling, and to ease the tasks of model development and experimentation. Earlier work has shown that CGM can provide reasonably accurate simulations at a processing speed several orders of magnitude faster than FDM or FEM. This note describes and demonstrates refinements to the CGM approach that increase its modeling accuracy to a level comparable to FEM, while doubling its processing speed. These refinements are: (1) the use of a hybrid linear regression model with an artificial neural network (ANN) to represent each coarse-grain modeling element (the hybridization of the ANN effectively halves its complexity); and (2) a linear calibration of the ANN-based coarse-grain modeling elements to account for an observed positive bias in their predictions. The improved approach is demonstrated for a two-dimensional model of a bay in a research building located at the University of Florida. The note concludes with some suggestions for continuing research.     

New Omics—Derived Perspectives on Retinal Dystrophies: Could Ion Channels-Encoding or Related Genes Act as Modifier of Pathological Phenotype?

Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. Here, ion channels play a role in several physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to a wide spectrum of ocular diseases collectively called channelopathies, a subgroup of inherited retinal dystrophies. Such mutations result in either a loss or gain-of channel functions affecting the structure, assembly, trafficking and localization of channel proteins. We investigated the probands of seven Italian and Egyptian families affected by not completely defined forms of inherited retinal dystrophies, by whole exome sequencing (WES) experiments, and found interesting variants in already known causative genes probably able to impair retinal functionalities. However, because such variants did not completely explain the phenotype manifested by each patient, we proceed to further investigate possible related genes carrying mutations that might complement previously found data, based on the common aspect linked to neurotransmission impairments. We found 10 mutated genes whose variants might alter important ligand binding sites differently distributed through all considered patients. Such genes encode for ion channels, or their regulatory proteins, and strictly interact with known causative genes, also sharing with them synaptic-related pathways. Taking into account several limitations that will be resolved by further experiments, we believe that our exploratory investigation will help scientists to provide a new promising paradigm for precise diagnosis of retinal dystrophies to facilitate the development of rational treatments.     

Numerical and experimental investigation of parabolic trough collector with focal evacuated tube and different working fluids integrated with single slope solar still

This study deals with the design and fabrication of parabolic trough solar collectors (PTCs) used to increase the yield of a single slope solar still. The designed parabolic trough solar collector is investigated numerically using Ansys Fluent 18.2. The proposed solar still is coupled with a parabolic trough solar collector with an evacuated tube receiver in its focal axis using different working fluids. The working fluids are water (case 1), oil (case 2), and nano-oil (CuO/mineral oil 3% vol; case 3). In the case when the working fluid is not water, then a heat exchanger serpentine should be used in the solar still basin. The PTC has a rim angle of 82° and an aperture width of 0.9 m and length of 2.8 m. An assessment of the performance for the studied systems was accomplished under the weather conditions of Ismailia, Egypt, during summer months, June, July, and August 2019. The outcomes of closed-loop working fluids different flow rates are investigated. The experimental results of the accumulated freshwater productivities record 2.955, 3.475, 4.29, and 5.04 L m⁻² d⁻¹ for the traditional solar still and the modified cases 1 to 3 solar stills, respectively. The modified solar still in case 3 has the highest daily accumulated freshwater productivity with a percentage increase of 71.2% than the traditional solar still. The maximum daily efficiency is 46% and 26.9% for the traditional and modified (case 3) solar stills, respectively. The cost of 1 L of fresh water is 0.057 and 0.062 $/L for the traditional and the modified (case 3) solar stills, respectively.     

Peristaltic motion with heat and mass transfer of nano-Williamson fluids in two layers

In this paper, we have investigated the peristaltic motion with heat and mass transfer through a vertical channel divided into two equal regions, the right region filled with a clear non-Newtonian fluid obeying the Williamson model and the left region with a nano-Williamson fluid. The system is stressed by a gravity force with a uniform external magnetic field. The problem is modulated mathematically with a system of coupled nonlinear partial differential equations that describe the velocities, temperatures, and concentration of the fluids. The system of nondimensional, nonlinear, and partial differential equations is solved analytically with the homotopy perturbation method after using the approximations of low Reynolds number and long wavelength. The obtained solutions are functions of the physical parameters of the problem. Then, the effects of these parameters on velocities, temperatures, and concentration are discussed numerically and illustrated graphically through a set of figures. It is found that the parameters play an important role in controlling the solutions. It is shown that the stream function decreases on the left side and increases on the right side with an increase in the Wissenberger parameter and thermal conductivity ratio. Also, the temperature in the two regions increases with an increase in the thermophoretic parameter, whereas it decreases with an increase in the Brownian motion parameter. Furthermore, the concentration increases with an increase in the Brownian motion parameter and decreases with an increase in the thermophoretic parameter.     

Experimental study on minimal nanolubrication with surfactant in the turning of titanium alloys

The superiority of minimal nanolubrication for effective, efficient and cleaner machining environment has been widely discussed in the literature. However, due to their high surface energy, nanoparticles coagulate or agglomerate easily, which makes it difficult to disperse them in the base fluid. Hence, the addition of a small amount of surfactant should be able to overcome this issue. This research elucidates and extends fundamental knowledge regarding the effect of a sodium dodecyl benzene sulfonate surfactant mixed with different nanoparticle concentrations towards the sustainable machining of titanium alloy using design of experiment methodology. The experimental results indicate that the inclusion of a sodium dodecyl benzene sulfonate surfactant in aluminium oxide nanolubricant provides the best lubricating properties for the machining of the titanium alloy. At 0.4 wt% of nanoparticles and a feed rate of 0.1 mm/rev, minimum values of surface roughness and power consumption can be achieved. Meanwhile, minimal tool wear can be attained by application of a 0.6 wt% nanoparticle concentration and 0.1 mm/rev feed rate. Further statistical analyses emphasized that the feed rate was the most significant factor that influenced the surface roughness and power consumption, while the mixture of nanoparticles with surfactant and feed rate has the greatest effect on the tool wear resistance of the cutting insert.     

Optical realization of bioinspired spiking neurons in the electron trapping material thin film

A thin film of electron-trapping material (ETM), when combined with suitable optical bistability, is considered as a medium for optical implementation of bioinspired neural nets. The optical mechanism of ETM under blue light and near-infrared exposure has the inherent ability at the material level to mimic the crucial components of the stylized Hodgkin-Huxley model of biological neurons. Combining this unique property with the high-resolution capability of ETM, a dense network of bioinspired neurons can be realized in a thin film of this infrared stimulable storage phosphor. When combined with suitable optical bistability and optical interconnectivity, it has the potential of producing an artificial nonlinear excitable medium analog to cortical tissue.     

Inhibition of Listeria monocytogenes by enterocin EJ97 produced by Enterococcus faecalis EJ97

Enterocin EJ97 from Enterococcus faecalis EJ97 showed a concentration-dependent antimicrobial activity against Listeria monocytogenes CECT 4032. Activity of enterocin EJ97 against L. monocytogenes CECT 4032 increased slightly at 4 degrees C, and cold-adapted cells did not show any increased resistance. Sensitivity of L. monocytogenes CECT 4032 to enterocin EJ97 was not modified by the addition of sodium benzoate, sodium acetate, NaCl or sodium tripolyphosphate. Anti-listeria activity was enhanced by potassium nitrate, and especially by sodium nitrite at concentrations of 50 microg/ml or above. E. faecalis EJ97 produced bacteriocin activity during cocultivation with L. monocytogenes CECT 4032 at 37 degrees C and also at 15 degrees C, but not at 4 degrees C. Growth of L. monocytogenes CECT 4032 was inhibited by bacteriocin produced during cocultivation at 37 and 15 degrees C, and the degree of inhibition was influenced by the incubation temperature and the initial concentrations of enterococci and listeria. E. faecalis EJ97 also produced bacteriocin during cocultivation in half-skimmed milk, although its capacity to control L. monocytogenes was limited to populations of 10(3) CFU/ml or lower.     

Effect of enterocin EJ97 against Geobacillus stearothermophilus vegetative cells and endospores in canned foods and beverages

Geobacillus stearothermophilus is a thermophilic bacterium typically responsible for the flat-sour spoilage of low-acid canned food with high water activity. Control of vegetative cells and spores of G. stearothermophilus strains CECT 48 and CECT 49 by enterocin EJ97 produced by Enterococcus faecalis EJ97 is described. Both strains were highly sensitive to EJ97 in a culture medium. In samples from canned foods inoculated with a cocktail of vegetative cells or endospores of the two strains and stored at 45 °C for 30 days, viable cell counts were reduced below detection levels. The time course of microbial inactivation depended on the food sample and bacteriocin concentration. Dormant endospores were resistant to EJ97 short-time treatments (5 min), but endospores activated to germinate by heat became bacteriocin sensitive. The simultaneous application of enterocin EJ97 and heat treatments (90 and 95 °C) on dormant endospores had an increased antimicrobial effect that depended both on the bacteriocin concentration and the heat temperature. Results from this study strengthen the potential of enterocin EJ97 for biopreservation against G. stearothermophilus in canned vegetable foods and drinks.     

A case-control study on the association of idiopathic recurrent pregnancy loss with autoantibodies against beta2-glycoprotein I and annexin V

Whereas antiphospholipid antibodies (aPL) are associated with thrombotic events and recurrent spontaneous abortion (RSA), the contribution of anti-beta2 glycoprotein 1 (beta2GP1) and anti-annexin V antibodies as risk factors for RSA remain poorly understood. We investigated anti-beta2-GPI and anti-annexin V IgM and IgG antibodies as potential risk factors for RSA in 200 women with more than three consecutive idiopathic RSA, and 200 age-matched, healthy, parous women. Pearson's chi squared test analysis showed that while anti-beta2-GPI IgG (P = 0.416) and IgM (P = 0.72) were comparable between patients and controls, elevated anti-annexin V IgG (P = 0.006), but not IgM (P = 0.084), was more pronounced in patients. Higher frequencies of elevated IgG-only (P = 0.005), but not IgM-only (P = 1.000; OR = 6.66), anti-annexin V antibodies were noted among patients. Multinomial regression analysis showed that body-mass index (overweight and obesity; P = 0.008), education status (P < 0.001) and anti-beta2-GPI IgM (P = 0.033), but not IgG (P = 0.723), were associated with early abortion, while anti-beta2-GPI IgG (P = 0.030) and anti-annexin V IgG (P = 0.004) were associated with late RSA. For combined early-late RSA, the only variable selected was education status (P < 0.001), and neither anti-annexin V nor anti-beta2-GPI IgM and IgG was associated with early-late RSA. Accordingly, anti-annexin V and anti-beta2-GPI should be regarded as independent risk markers of RSA.