A Through-Life Cost Analysis Model to Support Investment Decision-Making in Concentrated Solar Power Projects

This research paper aims to propose a through-life cost analysis model for estimating the profitability of renewable concentrated solar power (CSP) technologies. The financial outputs of the model include net present value (NPV) and benefit-cost ratio (BCR) of the project, internal rate of return (IRR) and discounted payback period (DPBP) of the investment, and levelized cost of energy (LCoE) from the CSP technology. The meteorological data for a specific location in the city of Tucson in Arizona is collected from a network of automated weather stations, and the NREL System Advisor Model (SAM) is applied to simulate hourly energy output of the CSP plant. An Excel spreadsheet tool is designed to calculate, in a bottom-up approach, the financial metrics required for approval of CSP projects. The model is tested on a 50MW parabolic trough CSP plant and the results show an annual energy production of 456,351,232 kWh, NPV of over $64 million and LCoE of 0.16$/kWh. Finally, a sensitivity analysis is performed to identify the factors which have the most significant effect on the economic performance of CSP technologies. The proposed model can provide valuable guidance to support the strategic planning and investment decision-making in CSP projects

Performance Comparison Between Isothermal Hot Corrosion And In Situ Cyclic Hot Corrosion of Nickel-Based Superalloys

Although a lot of work has been done to understand both major mechanisms of hot corrosion, namely type I (high-temperature hot corrosion) and type II (low temperature hot corrosion), there is very little information available on more representative cyclic performance in these regimes. This work addresses this by assessing the performance of isothermal (type I and type II) hot corrosion tests against combined (short and long) cyclic corrosion tests. Single-crystal alloy PWA 1484 and directionally solidified alloy MAR-M247 were assessed in all test regimes. Pre- and post-exposure dimensional metrology was used to quantify the corrosion damage and characterised using SEM/EDX. This paper highlights that the results of short cycle test conditions are more damaging compared to long cycle and standard isothermal type I and II test conditions. The cast nickel-based alloy MAR-M247 was found to be a better performer compared to PWA 1484 single-crystal alloy

Performance Comparison Between Isothermal Hot Corrosion And In Situ Cyclic Hot Corrosion of Nickel-Based Superalloys

Although a lot of work has been done to understand both major mechanisms of hot corrosion, namely type I (high-temperature hot corrosion) and type II (low temperature hot corrosion), there is very little information available on more representative cyclic performance in these regimes. This work addresses this by assessing the performance of isothermal (type I and type II) hot corrosion tests against combined (short and long) cyclic corrosion tests. Single-crystal alloy PWA 1484 and directionally solidified alloy MAR-M247 were assessed in all test regimes. Pre- and post-exposure dimensional metrology was used to quantify the corrosion damage and characterised using SEM/EDX. This paper highlights that the results of short cycle test conditions are more damaging compared to long cycle and standard isothermal type I and II test conditions. The cast nickel-based alloy MAR-M247 was found to be a better performer compared to PWA 1484 single-crystal alloy

On the rotational dynamics of the Rattleback

The Rattleback is a very popular science toy shown to students all over the world to demonstrate the non-triviality of rotational motion. When spun on a horizontal table, this boat-shaped object behaves in a peculiar way. Although the object appears symmetric, the dynamics of its motion seem very asymmetric. When spun in the preferred direction, it spins smoothly, whereas in the other direction it starts to oscillate wildly. The oscillation soon dies out and the rattleback starts to spin in the preferred way. We will construct and go through an analytical model capable of explaining this behaviour in a simple and intelligible way. Although we aim at a semi-pedagogical treatise, we will study the details only when they are necessary to understand the calculation. After presenting the calculations we will discuss the physical validity of our assumptions and take a look at more sophisticated models requiring numerical analysis. We will then improve our model by assuming a simple friction force.Comment: 17 pages and 2 figures, typos corrected, some minor additions and rewording

Effects of oxidation and hot corrosion in a nickel disc alloy

This paper describes work to study oxidation and hot corrosion damage in nickel disc alloy RR1000. Oxidation damage has been characterised via mass change data from thermogravimetric analyses at temperatures from 700 to 800 ºC and cyclic oxidation testing at 700 and 750 ºC. Thin oxide scales rich in Cr and Ti have been found to grow in a parabolic dependence with time. Oxidation rate constants have been correlated with temperature using an Arrhenius equation. Through the use of simplifying assumptions, mass change data have been converted to oxide thickness values. These values have been compared with observed values of oxide scale and the depth of near-surface damage, which have been measured using focused ion beam (FIB) microscopy. Hot corrosion of RR1000 has been studied in the laboratory by ‘deposit' recoat experiments at 700ºC. In these tests, samples were coated with deposits of Na2SO4/NaCl salt in a gas stream of air-300 vpm SO2. Corrosion damage has been quantified by dimensional metrology of samples before and after exposure. This enabled metal losses, i.e. the depth of corrosion pits, to be determined. Distributions of metal loss data were then generated to produce median damage values and exceedance cumulative probabilities. Finally, the effect of contaminants on the hot corrosion resistance of RR1000 has also been evaluated

Self-healing materials and products survey and workshop data

This data set are the results of: an online survey distributed to manufacturers and a workshop carried out with industry participantsThis is the dataset used for the Haines-Gadd et al. (2021) article "Self-healing materials: a pathway to immortal products or a risk to circular economy systems?" published in the Journal of Cleaner production

Dipolar interactions in arrays of nickel nanowires studied by ferromagnetic resonance

Using a planar microstrip transmission line, the dipolar interactions in electrodeposited Ni nanowires arrays an characterized as a function of the membrane porosity (4% to 38%) and the wire diameter (56 to 250 nm). The dipolar interactions between the wires can be modeled in a mean-field approach as an effective uniaxial anisotropy field oriented perpendicular to the wire axis and proportional to the membrane porosity. The dipolar interaction field opposes the self-demagnetization field of an isolated single wire which keeps the magnetization parallel to the wire axis. An increase in the porosity therefore induces a switching of the effective anisotropy easy axis from parallel to perpendicular to the win axis above a critical porosity of 35-38% independent of the wire diameter

Smallholders’ Preferences for Improved Quinoa Varieties in the Peruvian Andes

Due to an increase in international demand, quinoa production has boomed tremendously in the Andes since the early 2010s. This has led to significant investments into developing improved varieties for large-scale agribusinesses, but breeding programs are not tailored to the needs of smallholders. In this paper, we study farmers’ preferences and willingness to pay for improved quinoa varieties in the Junín region in Peru. We use data from a choice experiment among 458 smallholders and estimate generalized multinomial logit models to control for preference and scale heterogeneity. We find that farmers generally prefer improved varieties over traditional varieties, with mildew-resistance as the most important crop trait. In general, farmers prefer varieties that are characterized by larger grain sizes, higher yield levels, lower levels of saponin, and a reduced maturation period. Yet, food-insecure farmers are found to be indifferent to early maturity and a larger grain size, which can be explained by a lower degree of commercialization among these farmers. Our results imply that developing mildew-tolerant and higher-yielding varieties with a medium to low saponin content is a priority if investments in quinoa technologies are to benefit small-scale and food insecure farmers in the Andean highlands of Peru

Effect of dipolar interactions on the ferromagnetic resonance properties in arrays of magnetic nanowires

The microwave absorption properties of arrays of magnetic nanowires electrodeposited in nanoporous membranes have been studied using a strip transmission line configuration. From the measurements, the ferromagnetic resonance properties of the magnetic wires have been extracted at frequencies ranging from 100 MHz to 40 GHz for various angles between the wire axis and an external static magnetic field up to 8 kOe. We report on extensive data obtained on the ferromagnetic resonance properties in arrays of nanowires of Ni, NiFe, and NiFeCo alloys with various diameters and packing densities. In such arrays, apart from the shape anisotropy, a strong dipolar coupling between wires is present which can be modulated by the wire density. Both ferromagnetic resonance spectra and hysteresis loops show that this coupling acts as an additional uniaxial anisotropy favoring an easy axis perpendicular to the wires. In particular, it is shown that the easy axis of magnetization can be tuned parallel or perpendicular to the wire axis by changing the wire packing density. Furthermore, ferromagnetic resonance occurs even at zero field and the resonance frequency is fixed by the saturation magnetization of the material independent of the packing density. (C) 2001 American Institute of Physics

Microwave and ferromagnetic properties of magnetic nanowires

This paper shows the microwave properties of a magnetic nanowired substrate studied in a microstrip line configuration. The ferromagnetic resonance (FMR) properties are investigated using a scalar network analyzer (SNA) in the frequency range from 100 MHz to 40 GHz and under a static magnetic field up to 10 kOe. The FMR properties extracted from measurements are in very good agreement with those expected for the classical FMR theory. At the FMR frequency, the microwave energy transported by the electromagnetic wave propagating inside the microstrip, is completely absorbed. Absorption phenomena have been observed in the presence but also in the absence of the DC magnetic field. The application of such a DC field is necessary for classical ferrites but not suitable for compact devices. Hence, a magnetic nanowired substrate is a good choice for designing microwave planar devices such as stopband filters, attenuators, and thin magnetic field sensors.Anglai