This paper presents an ORC-based micro-CHP system designed for use in residential houses. Two working fluids, R1223zd(E) and n-Pentane, are investigated and the performance of the ORC is compared. ...Experimental results show that the ORC-based micro-CHP system with R1223zd(E) used as the working fluid achieves slightly higher efficiency than with n-Pentane, with the ORC efficiencies being 7.6% and 7.3%. The system produces the electricity outputs of 0.98 kWe and 0.95 kWe at nominal operating conditions when the two fluids are used respectively. A thermodynamic model for the ORC is developed to predict its thermodynamic performance and evaluate different working fluids. The results of thermodynamic modelling show that the ORC efficiencies achieved with the two ORC fluids range from 6.6% to 13.6% and from 6.2% to 13.8% depending on operating conditions. The micro-CHP system is capable of delivering great performance with respect to overall energy efficiency, low GWP and on-site power and heating security for homes.
•An ORC-based micro-CHP system was investigated using R1233zd (E) and n-Pentane as working fluids.•Testing has proved R1223zd(E) and n-Pentane to be acceptable ORC fluids for small-scale ORC systems.•Modelling simulations show an ORC efficiency of 13% can be achieved at the operating conditions for residential applications.•The findings of this study provide useful information for improving ORC system performance in the future.
Biodegradable metals have attracted considerable attentions in recent years. Besides the early launched biodegradable Mg and Fe metals, Zn, an essential element with osteogenic potential of human ...body, is regarded and studied as a new kind of potential biodegradable metal quite recently. Unfortunately, pure Zn is soft, brittle and has low mechanical strength in the practice, which needs further improvement in order to meet the clinical requirements. On the other hand, the widely used industrial Zn-based alloys usually contain biotoxic elements (for instance, ZA series contain toxic Al elements up to 40 wt.%), which subsequently bring up biosafety concerns. In the present work, novel Zn-1X binary alloys, with the addition of nutrition elements Mg, Ca and Sr were designed (cast, rolled and extruded Zn-1Mg, Zn-1Ca and Zn-1Sr). Their microstructure and mechanical property, degradation and in vitro and in vivo biocompatibility were studied systematically. The results demonstrated that the Zn-1X (Mg, Ca and Sr) alloys have profoundly modified the mechanical properties and biocompatibility of pure Zn. Zn-1X (Mg, Ca and Sr) alloys showed great potential for use in a new generation of biodegradable implants, opening up a new avenue in the area of biodegradable metals.
•The viability of converting a scroll compressor into an expander for use in an ORC was examined.•A test rig was built where the expander was driven by compressed air.•The power output of the ...expander increased significantly with increasing rotating speed.•Based on the expander tested, an ORC system was specified and simulated, and the resulting efficiency of the ORC was 6.9%
Micro combined heat and power systems using an organic Rankine cycle (ORC) as a prime mover are under development. The ORC is capable of utilizing various heat sources. The key component in the ORC is an expander to produce the electric power, yet such an expander for residential applications has, to date, not been commercially available. The present study aims to investigate the performance of a scroll expander that has been converted from a commercial refrigeration scroll compressor, as these scroll machines are generally mass-produced as compressors in refrigeration applications. The viability of converting a scroll compressor into an expander for use in an ORC was examined in this paper. A test rig was built where the expander was driven by compressed air and the scroll expander was evaluated under various operating conditions, providing fundamental data that could form the basis for ORC applications. It has been found that conversion of a scroll compressor into an expander is feasible without major modifications. Experiments showed that the power output of the expander increased significantly with increasing rotating speed. The mechanical efficiency of the expander ranged from 62.7% to 60.9% at the rotating speeds of 1600–3995 rpm and the adiabatic efficiency increased from 55.5% to 58.5% at the tested rotating speeds, whereas the total efficiency varied between 34.8% and 35.6%. Based on the expander tested, an ORC system was specified and the resulting efficiency of the ORC, through modelling, was determined to be 6.9%. It was noted that the built-in volume ratio of the compressor may need to be optimized, when operating in reverse, as an expander, in order to achieve a higher ORC efficiency.
During translation, an mRNA is typically occupied by multiple ribosomes sparsely distributed across the coding sequence. This distribution, mediated by slow rates of initiation relative to ...elongation, ensures that they rarely collide with each other, but given the stochastic nature of protein synthesis, collision events do occur. Recent work from our lab suggested that collisions signal for mRNA degradation through no-go decay (NGD). We have explored the impact of stalling on ribosome function when NGD is compromised and found it to result in +1 frameshifting. We used reporters that limit the number of ribosomes on a transcript to show that +1 frameshifting is induced through ribosome collision in yeast and bacteria. Furthermore, we observe a positive correlation between ribosome density and frameshifting efficiency. It is thus tempting to speculate that NGD, in addition to its role in mRNA quality control, evolved to cope with stochastic collision events to prevent deleterious frameshifting events.
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•Mutations that inhibit NGD promote +1 frameshifting on stalling sequences•+1 frameshifting efficiency depends critically on the stall-sequence location•Higher translation initiation rates lead to increased +1 frameshifting•Ribosome bumping is required to promote +1 frameshifting in a reconstituted system
Ribosome collisions, resulting from stalling, activate quality control processes to degrade the aberrant mRNA and the incomplete peptide. mRNA degradation proceeds through an endonucleolytic cleavage between the stacked ribosomes, which resolves the collisions. Simms et al. show that, when cleavage is inhibited, colliding ribosomes move out of frame.
In the case of medical implants, foreign materials are preferential sites for bacterial adhesion and microbial contamination, which can lead to the development of prosthetic infections. Commercially ...biomedical TiNi shape memory alloys are the most commonly used materials for permanent implants in contact with bone and dental, and the prevention of infections of TiNi biomedical shape memory alloys in clinical cases is therefore a crucial challenge for orthopaedic and dental surgeons. In the present study, copper has been chosen as the alloying element for design and development novel ternary biomedical Ti‒Ni‒Cu shape memory alloys with antibacterial properties. The effects of copper alloying element on the microstructure, mechanical properties, corrosion behaviors, cytocompatibility and antibacterial properties of biomedical Ti‒Ni‒Cu shape memory alloys have been systematically investigated. The results demonstrated that Ti‒Ni‒Cu alloys have good mechanical properties, and remain the excellent shape memory effects after adding copper alloying element. The corrosion behaviors of Ti‒Ni‒Cu alloys are better than the commercial biomedical Ti‒50.8Ni alloys. The Ti‒Ni‒Cu alloys exhibit excellent antibacterial properties while maintaining the good cytocompatibility, which would further guarantee the potential application of Ti‒Ni‒Cu alloys as future biomedical implants and devices without inducing bacterial infections.
We experimentally demonstrate all-optical amplitude regeneration of 4-level pulse amplitude modulated signals (PAM4) based on a single nonlinear optical loop mirror (NOLM). Four power-plateau regions ...are achieved using return-to-zero (RZ) pulses of narrow pulse-width, enabling large nonlinear phase shifts within the highly nonlinear fiber (HNLF). We quantify noise suppression characteristics at each amplitude level and obtain an overall EVM improvement of 0.92dB by optimizing input power and distortion strength. A theoretical analysis has been also carried out matching the experimental results and revealing the design characteristics of the regenerator's nonlinear transfer function.
We developed a new ordinary differential equation (ODE) to represent subsurface flows from a hillslope with artificial subsurface drainage (tiling) into an adjacent channel. Our ODE is based on a ...derived storage‐discharge relationship from high‐resolutions HYDRUS3D simulations that solve 3D partial differential Richards' equations for a hillslope (plot scale) with internal drainage surfaces, variable soil depth, hydraulic conductivity, and varying slope in the direction of flow. The ODE does not capture the hysteresis in the storage‐drainage relation that can only be captured using partial differential equations (PDEs), however the simplification does not have major impacts on the modeled flows. The nondimensional representation of the equation is consistent with, and provides an explanation for, the empirical equation used in classical hydrological models such as the ARNO (Arno River) and Variable Infiltration Capacity (VIC) model to simulate subsurface flows, which removes the need for parameter calibration. Our equation captures the features not captured by other ODE simplifications such as DRAINMOD. The ODE can be coupled to the Hillslope Link Model (HLM) flood forecasting system allowing real‐time regional simulation of streamflow fluctuations and floods over large domains. We show that (i) the new equation improves the capability to model watershed scale hydrograph recessions and to better capture the timing above flood thresholds for multiple spatial scales from 0.1 to 18,000 km2; (ii)using realistic values of slope combined with typical values of tile separation and soil depth provides good predictive power at gauged basin outlets; and (iii) parameters can be derived for particular situations using the 3D PDE framework.
Plain Language Summary
A new equation to calculate the subsurface drainage from landscapes modified by artificial drainage tiles has been developed. The equation has been coupled to the Hillslope Link Model to show that the equation captures the main features of this physical process. The predicted streamflow at many gauged locations in Iowa draining landscapes which are artificially drained coincide with observations.
Key Points
We develop an ordinary differential equation (ODE) to represent subsurface flow in a drained (tiled) and undrained hillslope
When our equation is applied in a hillslope model and combined into a network using a Hillslope Link Model, it can replicate streamflows
This process‐driven model can help to explain recession curves in hydrographs at the watershed scale
The economics of long haul trucking on both continuous and intermittent Electric Highways were evaluated from a technical perspective as alternatives to using conventional megawatt chargers. The ...study revealed complex and sensitive interplay between the various technical factors related to the vehicle, its battery pack and the configuration and construction of the electrified highway. Key preliminary outcomes showed that a 250 kW highway power supply level allows a 36 tonne truck to drive continuously without requiring off-road recharging, and it can operate with a battery pack of about 50% of the size required for a truck only using megawatt charging. For now, while there is no overwhelming case in favour of any particular technology, the study serves to highlight the relevant factors impacting anticipated design criteria for the electrification of highways.
► A novel cascading thermophotovoltaic (TPV) and thermoelectric (TE) power generation system is proposed and developed. ► The used heat stream is taken from the TPV and applied to the input of a TE ...converter in the system. ► A prototype was built and tested where GaSb TPV cells and PbSnTe-based TE converter were used. ► The TPV cells generate 123.5
We whereas the TE converter generates 306.2
We in the prototype. ► It is shown the cascading power generation is feasible in fuel-fired furnaces and can be applied to micro-CHP.
Thermophotovoltaic (TPV) cells can convert infrared radiation into electricity. They open up possibilities for silent and stand-alone power production in fuel-fired heating equipment. Similarly, thermoelectric (TE) devices convert thermal energy directly into electricity with no moving parts. However, TE devices have relatively low efficiency for electric power generation. In this study, the concept of cascading TPV and TE power generation was developed where the used heat stream is taken from the TPV and applied to the input of a TE converter. A prototype cascading TPV and TE generation system was built and tested. GaSb TPV cells and an integrated semiconductor TE converter were used in the cascading power system. The electric output characteristics of the TPV cells and the TE converter have been investigated in the power generation system at various operating conditions. Experimental results show that the cascading power generation is feasible and has the potential for certain applications.
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