Evaluation of the Potential of Nanofluids Containing Different Ag Nanoparticle Size Distributions for Enhanced Solar Energy Conversion in Hybrid Photovoltaic-thermal (PVT) Applications

Hybridising photovoltaic and photothermal technologies into a single system that can simultaneously deliver heat and power represents one of the leading strategies for generating clean energy at more affordable prices. In a hybrid photovoltaic-thermal (PVT) system, the capability to modulate the thermal and electrical power output is significantly influenced by the spectral properties of the heat transfer fluid utilised. In this study, we report on one of the first experimental evaluations of the capability of a multimodal silver nanofluid containing various particle shapes and particle sizes to selectively modulate the solar energy for PVT applications. The diverse set of particle properties led up to a 50.4% enhancement in the solar energy absorbed by the nanofluid over the 300 nm – 550 nm spectral region, where silicon is known to exhibit poor photovoltaic conversion performances. This improved substantially the absorption of solar energy, with an additional 18 – 129 W m-2 of thermal power being generated by the PVT system. Along with the advancements made in the thermal power output of the PVT system, a decrease of 4.7 – 36.6 W m-2 in the electrical power generated by the photovoltaic element was noted. Thus, for every ~11 W m-2 increase of thermal power achieved through the addition of the nanoparticles, a reduction of ~3 W m-2 in the ability to generate clean electricity was sustained by the PVT. Despite the energy trade-offs involved under the conditions of the nanofluid, the PVT system cumulatively harvested 405 W m-2 of solar energy, which amounts to a total conversion efficiency of 45%. Furthermore, the economics of the additional energy harvested through merging of the two systems was found to reach an enhancement of 77% under certain European conditions.

An SMA cable-based negative stiffness seismic isolator: Development, experimental characterization, and numerical modeling

Shape memory alloy (SMA)-based seismic isolation systems can successfully reduce the peak and residual displacements of bridges during strong earthquake, but they commonly lead to an increased force demands in substructure. This study explores the development of an SMA cable-based negative stiffness isolator to alleviate this problem. The proposed isolator is composed of superelastic SMA cables and a frictional sliding bearing with convex surfaces. The frictional sliding bearing limit the forces transferred to the superstructure and provides energy dissipation, while its built-in negative stiffness mechanism reduces the force demands in substructure. SMA cables provide critical restoring forces, additional energy dissipation, and displacement-limiting capacity. Based on the force balance, the negative stiffness and restoring requirements of the SMA cable-based negative stiffness isolator were analyzed first. Then, a prototype large-scale isolator was designed and fabricated. Next, the experimental testing of the developed isolator was performed under two different vertical load levels. Finally, finite element modeling of the proposed isolator was conducted, and the simulation results and experimental results were compared and discussed. The proposed isolator generates lower forces than the SMA-based zero and positive stiffness isolators and can exhibit stable energy dissipation capabilities with very good displacement-limiting and self-centering capabilities.

Different radiographic imaging modalities with a proton computed tomography demonstrator

Proton computed tomography aims at improving proton-beam therapy, which is an established method to treat deep-seated tumours in cancer therapy. In treatment planning, the stopping power (SP) within a patient, describing the energy loss of a proton in a tissue, has to be known with high accuracy. However, conventional computed tomography (CT) returns Hounsfield units (HU), which have to be converted to SP values to perform the required treatment planning, thus introducing range uncertainties in the calculated dose distribution. Using protons not only for therapy but also for the preceding planning CT enables the direct measurement of the SP. Hence, this imaging modality eliminates the need for further conversion and therefore offers the possibility to improve treatment planning in proton therapy. In order to examine the principles of such a proton CT (pCT) setup, a demonstrator system, consisting of four double-sided silicon strip detectors and a range telescope, was built. The performance of the pCT demonstrator was tested with measurements at the MedAustron facility in Wiener Neustadt, Austria. In this paper, 2D imaging modalities going beyond the idea of a standard proton radiography, will be discussed. Namely, fluence loss imaging and scattering radiography results obtained with the demonstrator will be shown. The advantage of these modalities is that they do not rely on an additional energy measurement and can therefore be conducted only with the tracker of the demonstrator.

A hydrogen generator coupled to a hydrogen heater for small scale portable applications

This study aims to build and test a small scale portable device able to couple a hydrogen generation system (based on a NaBH4 solution as liquid H2 carrier) to a hydrogen heater (based on the exothermic catalytic combustion of the released H2). The hydrogen generating system is based on the hydrolysis of stabilized solutions of NaBH4 (fuel solutions) which are pumped into the hydrolysis reactor. The generated H2 feeds the catalytic combustor. Two catalysts have been developed for the H2 generation and the combustion reactions able to operate at room temperature without need of additional energy supply. For the NaBH4 hydrolysis a Co-B catalyst was supported on a perforated and surface treated stainless steel (SS316) home-made monolith. For the flameless H2 catalytic combustion a Pt catalyst was prepared on a commercial SiC foam. The device was automatized and tested for the on-demand production of heat at temperatures up to 100ºC. In steady state conditions the NaBH4 solution flow is controlling the H2 flux and therefore the heater temperature. Once the steady-state is reached the system responds in a few minutes to up and down temperature demands from 80 to 100 ºC. The catalysts have shown no deactivation during the tests carried out in several days.

Information flow, Gating, and Energetics in dimeric molecular motors

Molecular motors belonging to the kinesin and myosin super family hydrolyze ATP by cycling through a sequence of chemical states. These cytoplasmic motors are dimers made up of two linked identical monomeric globular proteins. Fueled by the free energy generated by ATP hydrolysis, the motors walk on polar tracks (microtubule or filamentous actin) processively, which means that only one head detaches and executes a mechanical step while the other stays bound to the track. Thus, the one motor head must regulate chemical state of the other, referred to as "gating", a concept that is not fully understood. Inspired by experiments, showing that only a fraction of the energy from ATP hydrolysis is used to advance the kinesin motors against load, we demonstrate that additional energy is used for coordinating the chemical cycles of the two heads in the dimer - a feature that characterizes gating. To this end, we develop a general framework based on information theory and stochastic thermodynamics, and establish that gating could be quantified in terms of information flow between the motor heads. Applications of the theory to kinesin-1 and Myosin V show that information flow occurs, with positive cooperativity, at external resistive loads that are less than a critical value, Fc. When force exceeds Fc, effective information flow ceases. Interestingly, Fc, which is independent of the input energy generated through ATP hydrolysis, coincides with force at which the probability of backward steps starts to increase. Our findings suggest that transport efficiency is optimal only at forces less than Fc, which implies that these motors must operate at low loads under in vivo conditions.

ВИКОРИСТАННЯ ОПТОВОЛОКНА ЯК СКЛАДОВОЇ ЗАГАЛЬНОГО ЗОВНІШНЬОГО ОСВІТЛЕННЯДЛЯ СТВОРЕННЯ МАКСИМАЛЬНОГО РІВНЯ ЕНЕРГОЕФЕКТИВНОСТІ

Purpose. To develop a new lighting system for children's sports complexes. The introduction of the developed technology will improve the state of illumination of outdoor sports grounds without creating light pollution and increasing additional energy-efficient costs.Methodology. The combined technique of the technology of using two types of light sources, namely: low-power LED floodlights and optical fiber with a single light source, allows you to create an energy-efficient field illumination system. The proposed solution can be used for full illumination of street children's complexes. The selection of the parameters of the lighting system was carried out on the example of a real sports and children's complex.Findings. The performed measurements of the real parameters of the existing sports ground and taking into account its geometry allowed us to calculate the light parameters of light sources, select the appropriate materials and create a complete lighting model. A new lighting technology for sports and children's complexes has been developed, the level of lighting of sports facilities has been improved without creating light pollution.Originality. For the first time, a combined technology of illumination of sports and children's playgrounds was proposed using optical fiber and LED floodlights. The introduction of the developed technology will improve the state of illumination of such structures without creating an unnecessary light load on residents who are near the site. Moreover, such lighting will not lead to an increase in additional energy costs.Practical value. Today, most outdoor sports and entertainment venues are devoid of any lighting. The proposed complex solution can be used in any existing field lighting system. It is the most efficient and electrically safe because the optical fiber does not conduct electricity, but light. The light source itself can be located remotely and protected from vandals.

Screening, Isolation and Characterization of dye degrading bacteria from textile dye effluents.

Textile dye industry waste is one among the foremost serious issues within the atmosphere. The dye wastes are severely harmful to surface water bodies. The dye degradation and decolorisation processes, that embody several physical and chemical strategies having inherent drawbacks, like cost accounting, economically impracticable (require additional energy and chemicals), unable to get rid of a number of the recalcitrant dyes and production of huge quantity of sludge that if not properly treated, successively will cause secondary pollution. So, biological degradation, being eco-friendly and cheap methodology, is taken into account as an efficient methodology for the removal of nephrotoxic radical dyes. Our present study was therefore aimed to isolate dyestuff decolorizing microorganism from dyeing industry effluent associate degreed to check their characteristics so as to use them as an economical bio agent for decolorizing and mineralizing nephrotoxic radical dyes.Various microorganism like Bacillus subtilis, Aeromonas hydrophila and Bacillus Cereus, fungi & actinomycetes are found to possess dye decolorizing activity. For the aim of finding out their characteristics, water sample was subjected to enrichment culture technique and then isolated on sterile nutrient agar plates containing 0.005%, 0.01%, and 1% of Congo red dye. The probable isolated organism from Congo red dye i.e. Pantoea agglomerans was found which can possess the ability to decolorize Congo red at lower concentration. The probable isolates obtained must be additional investigated relating to varied factors like dye degradation capability, media composition affecting dye degradation & mechanism of dye degrading activity.

Analysis of energy losses in electric transmis-sion taking into account the Sommerfeld – Kononenko effect

The use of an electric drive in modern vehicles allows solving a number of problems related to the issues of environmental and energy security of the country. However, this approach imposes a number of practical limitations. Among them there is such a significant factor as the limitation on the stored energy in the traction batteries and, as a consequence, the limitation of the mileage on one charge. One of the ways to solve this problem is to reduce mechanical losses associated with the appearance of resonance phenomena in rotating transmission elements and having an unbalanced mass. Goal. The goal is to assess the influence of the Sommerfeld – Kononenko effect on energy indicators during the transfer of rotation from the electric motor to the drive wheel of an electric vehicle. To achieve this goal, it is necessary to determine the law of motion of the rotor of an electric motor and a car wheel using the energy approach and a model of complex motion. Methodology. To solve the problem of determining the law of rotation of an electric motor rotor, a dynamic model of an eccentric vibrator is adopted. The study takes into account the fluctuations in the angular velocity of the shaft with Hooke's hinge when the shaft axis deviates from horizontal positions. It is proposed to apply an energy approach using a model of complex motion to determine the law of rotation of an electric motor rotor and a wheel. Results. The dependence of the speed of rotation of the wheel of an electric vehicle is determined in accordance with the dynamic model under the conditions of fluctuations in the angular speed of transmission elements with Hooke's hinge when the wheel axis deviates from the horizontal position. Practical value. An energy approach is proposed for finding losses in a complex motion model to determine the law of rotation of an electric motor rotor and a wheel. An analytical dependence of additional energy losses caused by wheel unbalance on vehicle mileage and wheel unbalance is found.

Multi-Omics Analysis of Fatty Acid Metabolism in Thyroid Carcinoma

ObjectivePapillary thyroid carcinoma (PTC) accounts for the majority of thyroid cancer and affects a large number of individuals. The pathogenesis of PTC has not been completely elucidated thus far. Metabolic reprogramming is a common feature in tumours. Our previous research revealed the reprogramming of lipid metabolism in PTC. Further studies on lipid metabolism reprogramming may help elucidate the pathogenesis of PTC.MethodsClinical samples of PTC and para-tumour tissue were analysed using lipidomic, proteomic, and metabolomic approaches. A multi-omics integrative strategy was adopted to identify the important pathways in PTC. The findings were further confirmed using western blotting, tissue microarray, bioinformatics, and cell migration assays.ResultsMulti-omics data and the results of integrated analysis revealed that the three steps of fatty acid metabolism (hydrolysis, transportation, and oxidation) were significantly enhanced in PTC. Especially, the expression levels of LPL, FATP2, and CPT1A, three key enzymes in the respective steps, were elevated in PTC. Moreover, LPL, FATP2 and CPT1A expression was associated with the TNM stage, lymph node metastasis of PTC. Moreover, high levels of FATP2 and CPT1A contributed to poor prognosis of PTC. In addition, ectopic overexpression of LPL, FATP2 and CPT1A can each promote the migration of thyroid cancer cells.ConclusionsOur data suggested that enhanced fatty acid metabolism supplied additional energy and substrates for PTC progression. This may help elucidating the underlying mechanism of PTC pathogenesis and identifying the potential therapeutic targets for PTC.