Abstract: A new reductive catalytic fractionation biorefinery process (RCF) is currently being developed transforming wood into high-value end-products. RCF is considered to be in the pilot stage with a technology readiness level of 5–6. Apart from the RCF-process characteristics, the economic feasibility also depends on the investment decisions that are made upstream and downstream within the wood value chain, increasing the level of uncertainty. Two investment options within the value chain are considered: an option to invest in harvesting equipment and an option to invest in the RCF. To understand the impact of multiple sources of uncertainty on the decision to invest in an innovative RCF-driven wood value chain, an analytical two-factor real options model is presented, accounting for correlated cost and price uncertainties. Two different scenarios, separated and united investments in harvesting equipment and RCF, are analyzed. In both scenarios, market uncertainty postpones investment in comparison to the traditional NPV approach. When both investments are considered separately, the investment in RCF is expected to be earlier than the investment in harvesting equipment. When both investment decisions are united, the probability of investment increases. The study reveals that RCF has the potential to stimulate investments from different investors, –upstream and midstream–, within the wood value chain. Besides, the introduced real options model proofs its ability to assess the economic feasibility of innovative technologies (e.g RCF) individually or within the value chain, taking into account multiple sources of uncertainty.

Abstract: Most farm adaptations are reactive actions that run the risk of locking farm systems into suboptimal long-term trajectories. This is especially the case with regard to water management as water scarcity will be aggravated by climate change. This paper looks into farm irrigation choices in combination with crop choices because a proper crop choice has the potential to reduce water requirements. It proposes an extended Ricardian model to capture multiple adaptation decisions explicitly. The new simultaneous irrigation-crop farm decision model uses spatially detailed farm-level data of over 18,000 European farms on irrigation and seven different crop choices. The analysis shows that larger farmers and farmers in less water-scarce regions that use irrigation are more sensitive to temperature increases than rain-fed agriculture. This might be explained by the fact that these farmers do not experience the real cost of water scarcity because of which they take less efficient decisions.

Abstract: Farmers should increasingly adopt more water‐efficient irrigation technologies—such as drip irrigation—as a result of climate warming and aggravating water scarcity. We analyze how Italian farmers adapt to climate change by changing their irrigation technology mix. We apply a two‐stage econometric model to data from 5876 Italian farms. We find that farmers' initial reaction to increasing temperatures is reducing their surface‐irrigated fractions. When temperatures increase further, farmers switch toward more sprinkler irrigation. Our results show that farmers are not autonomously moving to drip irrigation in response to climate change, suggesting that government incentives are needed to encourage this transition.

Abstract: In 2023, the European Union will vote on the reauthorization of glyphosate use, renewed in 2017 despite concern on impacts on the environment and public health. A ban is supported by several Member States but rejected by most farmers. What are citizens’ preferences to phase out glyphosate? To assess whether taxation could be an alternative to a ban, we conducted a discrete choice experiment in five European countries. Our results reveal that the general public is strongly willing to pay for a reduction in glyphosate use. However, while 75.5% of respondents stated to support a ban in the pre-experimental survey, experimental results reveal that in 73.35% of cases, earmarked taxation schemes are preferred when they lead to a strong reduction in glyphosate use for an increase in food price lower than that induced by a ban. When glyphosate reduction is balanced against its costs, a tax may be preferred.

Abstract: Permanent magnets generally require a favorable, but difficult-to-achieve combination of high magnetization, Curie point, and magnetic anisotropy. Thus there have been few, if any, viable permanent magnets developed since the 1982 discovery of Nd2Fe14B [M. Sagawa, S. Fujimura, H. Yamamoto, Y. Matsuura, and S. Hirosawa, J. Appl. Phys. 57, 4094 (1985)]. Here we point out, both by direct first-principles calculations on the iron carbides and silicides Fe5C2, Fe5SiC, and Fe7C3 as well as a discussion of recent experimental findings, that there are numerous rare-earth-free iron-rich potential permanent-magnet materials with sufficient intrinsic magnetic properties to reasonably achieve room-temperature energy products of 20-25 MG Oe. This is substantially better than the performance of the best available rare-earth-free magnets based on ferrite, as well as shape-anisotropy-employing alnico. These magnets could plausibly fill, at low cost, the present performance “gap” [J. M. D. Coey, Scr. Mater. 67, 524 (2012)] between the best rare-earth-free magnets and rare-earth magnets such as Nd2Fe14B and Sm-Co.

Abstract: The adsorption of various environmental gas molecules, including H-2, N-2, CO, CO2, O-2, NO, NO2, SO2 H2O, H2S, NH3 and CH4, on the surface of the recently synthesized two dimensional MoSi2N4 (MSN) monolayer has been investigated by means of spin-polarized first-principles calculations. The most stable adsorption configuration, adsorption energy, and charge transfer have been computed. Due to the weak interaction between molecules studied with the MSN monolayer surface, the adsorption energy is small and does not yield any significant distortion of the MSN lattice, i.e., the interaction between the molecules and MSN monolayer surface is physisorption. We find that all molecules are physisorbed on the MSM surface with small charge transfer, acting as either charge acceptors or donors. The MSN monolayer is a semiconductor with an indirect band gap of 1.79 eV. Our theoretical estimations reveal that upon adsorption of H-2, N-2, CO, CO2, NO, H2O, H2S, NH3 and CH4 molecules, the semiconducting character of MSN monolayer is preserved and the band gap value is decreased to similar to 1.5 eV. However, the electronic properties of the MSN monolayer can be significantly altered by adsorption of O-2, NO and SO2, and a spin polarization with magnetic moments of 2, 1, 2 mu(B), respectively, can be introduced. Furthermore, we demonstrate that the band gap and the magnetic moment of adsorbed MSN monolayer can be significantly modulated by the concentration of NO and SO2 molecules. As the concentration of NO2 molecule increases, the magnetic moment increase from 1 mu(B) to 2 and 3 mu(B). In the case of the SO2 molecule with increasing of concentration, the band gap decreases from 1.2 eV to 1.1 and 0.9 eV. Obviously, our theoretical studies indicate that MSN monolayer-based sensor has a high application potential for O-2, NO, NO2 and SO2 detection.

Abstract: We compare three first-principles methods of calculating the Curie temperature in two-dimensional (2D) ferromagnetic materials (FM), modeled using the Heisenberg model, and propose a simple formula for estimating the Curie temperature with high accuracy that works for all common 2D lattice types. First, we study the effect of exchange anisotropy on the Curie temperature calculated using the Monte Carlo (MC), the Green's function, and the renormalized spin-wave (RNSW) methods. We find that the Green's function method overestimates the Curie temperature in high-anisotropy regimes compared to the MC method, whereas the RNSW method underestimates the Curie temperature compared to the MC and the Green's function methods. Next, we propose a closed-form formula for calculating the Curie temperature of 2D FMs, which provides an estimate of the Curie temperature that is greatly improved over the mean-field expression for magnetic material screening. We apply the closed-form formula to predict the Curie temperature 2D magnets screened from the C2DB database and discover several high Curie temperature FMs, with Fe2F2 and MoI2 emerging as the most promising 2D ferromagnets. Finally, by comparing to experimental results for CrI3, CrCl3, and CrBr3, we conclude that for small effective anisotropies, the Green's-function-based equations are preferable, while for larger anisotropies, MC-based results are more predictive.

Abstract: In this work, the carbon (C) and silicon (Si) doping and codoping effects on beta-arsenene (As) monolayer structural, electronic, and magnetic properties have been comprehensively investigated using first-principles calculations. The studied two-dimensional (2D) materials exhibit good stability. Pristine beta-As single layer is an indirect gap semiconductor with a band gap of 1.867(2.441) eV as determined by PBE(HSE06) functional. Due to the difference in atomic size and electronic interactions, C and Si substitution induces a significant local structural distortion. Depending upon dopant concentration and doping sites, feature-rich electronic properties including non-magnetic semiconductor, magnetic semiconductor and half-metallicity may be obtained, which result from p-p interactions. High spin-polarization at the Fermi level vicinity and significant magnetism suggest As:1C, As:2C, As:1Si, As:2Si, and As:CSi systems as prospective spintronic 2D materials. While, the C-C, Si-Si, and C-Si dimer doping decreases electronic band gap, making the layer more suitable for applications in optoelectronic devices. Results presented herein may suggest an efficient approach to create novel multi-functional 2D materials from beta-As monolayer.

Abstract: Recently, a two-dimensional (2D) MoSi 2N 4 (MSN) structure has been successfully synthesized [Hong et al., Science 369(6504), 670-674 (2020)]. Motivated by this result, we investigate the structural, electronic, and optical properties of MSN monolayer (MSN-1L) and bilayer (MSN-2L) under the applied electric field (E-field) and strain using density functional theory calculations. We find that the MSN-2L is a semiconductor with an indirect bandgap of 1.60 (1.80)eV using Perdew-Burke-Ernzerhof (HSE06). The bandgap of MSN-2L decreases as the E-field increases from 0.1 to 0.6V/angstrom and for larger E-field up to 1.0V/angstrom the bilayer becomes metallic. As the vertical strain increases, the bandgap decreases; more interestingly, a semiconductor to a metal phase transition is observed at a strain of 12 %. Furthermore, the optical response of the MSN-2L is in the ultraviolet (UV) region of the electromagnetic spectrum. The absorption edge exhibits a blue shift by applying an E-field or a vertical compressive strain. The obtained interesting properties suggest MSN-2L as a promising material in electro-mechanical and UV opto-mechanical devices.