Future Constraints Research Articles

Disturbance feedback-based model predictive control in uncertain dynamic environments

This paper presents a robust MPC scheme for linear systems subject to time-varying, uncertain constraints that arise from uncertain environments. The predicted input sequence is parameterized over future environment states to guarantee constraint satisfaction despite an imprecise environment prediction and unknown evolution of the future constraints. We provide theoretical guarantees for recursive feasibility and asymptotic convergence. Finally a brief simulation example showcases our results.

Improving the Performance of Flame-Retarding Sodium Bis(Oxalato)Borate in Triethyl Phosphate Electrolyte for Sodium Ion Batteries

An ever-growing demand for energy storage has highlighted potential future resource constraints for Li-ion batteries (LIBs), in particular with respect to Li.1-3 With this in mind Na-ion batteries (NIBs) hold promise as a complementary technology to LIBs, particularly for stationary energy storage.4 To be competitive with LIBs, NIBs need to become fully competitive on cost and on capacity density.5-7 NIBs can however offer more than simply a cost competitive option to LIBs, with potential to offer improvements on both safety and sustainability. A number of cathode materials exist that can avoid many of the unanswered question around the sustainability of state-of-the-art LIB cathodes.3 However, to address safety concerns of LIBs it is impossible to ignore the electrolyte. State of the art electrolyte in LIBs, regularly LiPF6 in a mix of carbonates, is both toxic (by virtue of LiPF6 and to a limited extent ethylene carbonate) and flammable (by virtue of the electrolyte solvents). Importing the Na analogue of state-of-the-art LIB electrolytes (i.e. NaPF6 in carbonates) creates the same problems of flammability and toxicity currently seen in LIBs (albeit the toxicity of NaPF6 is lower than that of LiPF6).Recently Mogensen et al.8 proposed sodium bis(oxalato)borate (NaBOB) in trimethyl phosphate (TMP) electrolyte that overcame the flammability concerns of NaPF6 in carbonate electrolytes. In addition to non-flammability, the use of NaBOB instead of NaPF6 allowed for higher temperatures to be used and produced an electrolyte that was halogen free. Switching from TMP to triethyl phosphate (TEP) allowed for a relatively less-toxic electrolyte (NaBOB and TEP are listed by the European Chemical Agency as ‘harmful if swallowed’ in comparison to ‘harmful if swallowed, in contact with skin or inhaled’ for NaPF6 in carbonates, although limited research has been conducted on the toxicity of NaBOB and so this should be received with limited certainty) without sacrificing cell performance.9 However, hurdles remain for NaBOB in organophosphate electrolytes. Principal amongst these has been the poor solubility of NaBOB in most solvents and the difficulties transferring promising low mass-loading full cell results to higher mass-loading full cells. The low solubility of NaBOB limits the concentration of NaBOB in organophosphate electrolytes to < 0.4 M, producing electrolytes with relatively low conductivities (for NaBOB in TMP, 4.5 mS/cm, and in TEP, 5 mS/cm). N-methyl pyrrolidone (NMP) has previously been shown to increase the solubility of NaBOB when used as a cosolvent with TMP, with conductivity improved to 6.5 mS/cm without sacrificing non-flammability and promising cycling shown in low mass-loading full-cells.10 A range of alternative cosolvents were here investigated to increase the solubility of NaBOB in TEP. Of these, NMP, N,N-dimethyl formamide (DMF) and N,N-dimethyl acetamide (DMAc) were evaluated as cosolvents with TEP for near-commercial mass loading full-cells (Prussian white||hard carbon at ~ 2 mAh/cm2). To maintain non-flammable characteristics, the cosolvents had to be kept below 40% (v/v) for DMAc and DMF and below 60% (v/v) for NMP, resulting in electrolyte conductivities of 5.7, 6.9 and 6.0 mS/cm respectively. These nearly doubled the conductivity we observed for NaBOB in TEP of 3.5 mS/cm. However, all electrolytes examined showed large polarisation, suspected to be due a thick, resistive SEI. A range of strategies have been employed in order to reduce this polarisation, with particular focus on improved formation protocols (studying the effects of temperature, current density and electrochemical method of formation) and their use in concert with film forming additives. Future work will aim to understand the interplay between formation conditions, the resultant SEI formation and the cell polarization in an effort to translate promising low mass-loading full cell results to near-commercial mass-loading full cells.

Particle filtering for dynamic systems with future constraints

This work focuses on a new state estimation problem for dynamic systems with future constraints. It is well known that constraints, as a priori, should always be satisfied by states of some dynamic systems, and thus sufficiently fusing the valuable information into filters will produce more accurate estimates. To this end, a particle smoothing framework is proposed by incorporating future constraints, instead of only current constraints. Next, we construct a criterion function by making the center value of dynamic model satisfy constraints to improve dynamic modeling accuracy, and investigate a cost function to compensate for the impact of the modified dynamic model on the original predicted distribution. Based on this, we present a new particle filter that future constraints are applied in importance sampling and updating particle weights. Especially, the modified dynamic model is chosen as the importance density function so that the sampled particles satisfy constraints at consecutive times as much as possible. Finally, two simulations verify the superiority of the proposed filter.

Isospin-violating dark matter at liquid noble detectors: new constraints, future projections, and an exploration of target complementarity

There is no known reason that dark matter interactions with the Standard Model should couple to neutrons and protons in the same way. This isospin violation can have large consequences, modifying the sensitivity of existing and future direct detection experimental constraints by orders of magnitude. Previous works in the literature have focused on the zero-momentum limit which has its limitations when extending the analysis to the Non-Relativistic Effective Field Theory basis (NREFT). In this paper, we study isospin violation in a detailed manner, paying specific attention to the experimental setups of liquid noble detectors. We analyse two effective Standard Model gauge invariant models as interesting case studies as well as the more model-independent NREFT operators. This work demonstrates the high degree of complementarity between the target nuclei xenon and argon. Most notably, we show that the Standard Model gauge-invariant formulation of the standard spin-dependent interaction often generates a sizeable response from argon, a target nuclei with zero spin. This work is meant as an update and a useful reference to model builders and experimentalists.

Neff constraints on light mediators coupled to neutrinos: the dilution-resistant effect

We investigate the impact of new light particles, carrying significant energy in the early universe after neutrino decoupling, on the cosmological effective relativistic neutrino species, Neff. If the light particles are produced from decoupled neutrinos, Neff is predominantly modified through the dilution-resistant effect. This effect arises because the energy stored in the mass of new particles is less diluted than the photon and neutrino energy as the universe expands. Our study comprehensively explores this effect, deriving Neff constraints on the couplings of light mediators with neutrinos, encompassing both scalar and vector mediators. We find that the dilution-resistant effect can increase Neff by 0.118 and 0.242 for scalar and vector mediators, respectively. These values can be readily reached by forthcoming CMB experiments. Upon reaching these levels, future Neff constraints on the couplings will be improved by many orders of magnitude.

Prediction of carbon emissions peak and carbon neutrality based on life cycle CO2 emissions in megacity building sector: Dynamic scenario simulations of Beijing

In order to design an optimal carbon peak and carbon neutralization pathway for the high-density building sector, a dynamic prediction model is established using system-dynamics coupled building life cycle carbon emission model (SD-BLCA) with consideration of future evolutionary trajectory and time constraints. The model is applied in Beijing using the SD-BLCA combined with scenario analysis and Monte Carlo methods to explore optimal trajectory for its building sector under 30-year timeframe. The results indicate that by increasing the proportion of renewable energy generation by 7% and retrofitting 60 million m2 of existing buildings, these two mature measures can offset the growth of carbon emissions and achieve the peak target by 2025. However, achieving carbon neutrality necessitates a shift from isolated technologies to a comprehensive net-zero emissions strategy. The study proposes a time roadmap that integrates a zero-carbon energy supply system and the carbon reduction measures of the whole life cycle. This strategy primarily relies on renewable sources to provide heat, power, and hydrogen, resulting in estimated reductions of 29.8 Mt, 28.1 Mt, and 0.7 Mt, respectively. Zero energy buildings, green buildings, and renovated buildings can reduce carbon emissions through their own energy-saving measures by 8.4, 18.2, and 11.8 kg/m2, respectively.

Present and future constraints on flavor-dependent long-range interactions of high-energy astrophysical neutrinos

The discovery of new, flavor-dependent neutrino interactions would provide compelling evidence of physics beyond the Standard Model. We focus on interactions generated by the anomaly-free, gauged, abelian lepton-number symmetries, specifically Le – Lμ, Le – Lτ , and Lμ – Lτ , that introduce a new matter potential sourced by electrons and neutrons, potentially impacting neutrino flavor oscillations. We revisit, revamp, and improve the constraints on these interactions that can be placed via the flavor composition of the diffuse flux of high-energy astrophysical neutrinos, with TeV–PeV energies, i.e., the proportion of νe, νμ, and ντ in the flux. Because we consider mediators of these new interactions to be ultra-light, lighter than 10−10 eV, the interaction range is ultra-long, from km to Gpc, allowing vast numbers of electrons and neutrons in celestial bodies and the cosmological matter distribution to contribute to this new potential. We leverage the present-day and future sensitivity of high-energy neutrino telescopes and of oscillation experiments to estimate the constraints that could be placed on the coupling strength of these interactions. We find that, already today, the IceCube neutrino telescope demonstrates potential to constrain flavor-dependent long-range interactions significantly better than existing constraints, motivating further analysis. We also estimate the improvement in the sensitivity due to the next-generation neutrino telescopes such as IceCube-Gen2, Baikal-GVD, KM3NeT, P-ONE, and TAMBO.

Youth and newcomers in Icelandic fisheries: opportunities and obstacles

Privatized fishery management schemes, alongside other cultural and social changes, have led to a high average age in some fisheries, where youth and newcomers are not meaningfully present in the industry. This research explored the current and future opportunities and constraints for youth and newcomers in Icelandic fisheries, which are managed by an Individual Transferable Quota system. Data were collected through participant observation and 25 semi-structured interviews with key individuals in fisheries. Inductive qualitative analysis of interview data determined recurrent themes that illustrate how rural outmigration, cost, and changing social expectations have led to a decrease of youth and newcomers in Icelandic fisheries. Results show that the perception of fishers in Iceland by the general society fluctuates as the economic and cultural climate of the country changes. The ageing of the fleet in small-scale fisheries is explained by the limited access to consolidated fisheries rights, and the inability for youth to secure capital and invest in a fishery operation. Large-scale fisheries, on the other hand, have a different set of barriers for youth, such as lack of career advancement opportunities and a heavy workload. This research also documents how the absence of youth in small-scale fisheries is partially linked to a high turnover of youth in large-scale fisheries. Youth have more opportunities in large-scale fisheries, but over time, they do not receive adequate training or support to further an independent career, thereby creating a negative feedback loop leading to further reduction of recruitment in small-scale fisheries. Findings from the study support the continued call from academics and practitioners to include issues of access for newcomers in fishery management goals.

Accumulation and transport of nutrient and pollutant elements in riparian soils, sediments, and river waters across the Thames River Watershed, Connecticut, USA

Understanding drivers of nutrient and pollutant elements (NPEs) in soils, sediments, and river water is important for protecting water resources and aquatic ecosystems. The objectives of this study were to quantify accumulation and transport of NPEs (P, As, Cd, Cu, Ni, Pb, and Zn) in riparian soils, sediments, river water, and watershed-scale exports within seven post-industrial subwatersheds of the Thames River, Connecticut, USA. Suspended sediments and river water samples were collected from February 2019 to January 2020. Arsenic concentrations in soil (6 to 18 mg kg−1) and sediments (8 to 85 mg kg−1) generally exceeded state and federal EPA quality targets but not river water. Elevated Pb ‘hot spots’ occurred in some riparian soils (>2000 mg kg−1) and sediments (>200 mg kg−1), but the other NPEs concentrations were below toxic thresholds. Riparian soil concentrations and watershed land cover were generally weak predictors for NPE concentrations in bottom sediments, suspended sediments, and river water. DOC, Mn, and Fe concentrations were important predictors for area-normalized dissolved and sediment-bound export of NPEs across the seven watersheds. Dissolved export was greater than sediment export for Mn, P, As, Cd, Cu, and Ni but not for Fe, Pb, and Zn. Watersheds with higher farmland had higher P river water concentrations, but the larger, more urbanized watershed had the highest total and area-normalized P export. An estuarine sediment core that captures sediment from the whole watershed and spans pre-industrial conditions through present shows that export of most NPEs has decreased since its peak, but all remain above baseline throughout the Thames River watershed. Future constraints on surface soil-river exchange and erosion inputs are needed to investigate rates of NPE sourcing to the watersheds.

Spatial adaptability evaluation and optimal location of electric vehicle charging stations: A win-win view from urban travel dynamics

The contradiction between charging stations (CSs) and electric vehicles (EVs) is a “chicken-and-egg” problem. Multiple factors and stakeholders, including the goals of the government's industry planning, CS operators' profits, and EV consumers' charging demand, influence the CS layout. Using multisource open data, this study proposes a time series optimization layout model based on the supply-demand balance by constructing EV customers' urban travel dynamics index and CS adaptability index. The results show that: the supply-demand imbalance is widespread in Shenzhen, a Chinese city. The “mismatch”, “unmatch” and “overmatch” of CSs are prevalent. Addressing this supply-demand imbalance will help reduce consumer concerns regarding “range anxiety”. Facing potential future power supply constraints, the government needs to expand the existing CS development strategy to include battery swap stations (BSs) and mobile charging stations (MCSs).

Present and future constraints on secluded dark matter in the Galactic Halo with TeV Gamma-ray observatories

The dark matter relic density may be governed by the presence of new mediators that connect the dark matter field with the Standard Model particles. When the dark matter particle mass is larger than the mediator's, the pair production of mediators is kinematically open. This setup is known in the literature as secluded dark matter. Motivated by the appearance of secluded dark matter in several model building endeavours, we investigate the sensitivity of TeV gamma-ray instruments in the Southern Hemisphere namely, H.E.S.S., CTA, and SWGO to secluded dark matter annihilating in the Galactic Halo. We exploit the complementarity aspects of these detectors to find restrictive bounds on the annihilation cross-section for different annihilation channels. In particular, for a dark matter particle mass of 2 TeV, H.E.S.S. is able to constraint 〈σv〉 ≥ 4 × 10-26 cm3 s-1 at 95% confidence level for the 4q and 4τ channel, while CTA will be sensitive to 〈σv〉 ≥ 7 × 10-27 cm3 s-1 and SWGO 〈σv〉 ≥ 6 × 10-27 cm3 s-1 for the 4τ channel, both well below the thermal relic cross-section. In fact, the combination of CTA and SWGO will be able to probe cross-sections below the thermal relic value for dark matter particles in the whole mass range between 100 GeV and 100 TeV in the 4q and 4τ channels, and between 100 GeV and ∼ 40 TeV in the 4b channel.

Toward neutrino mass from cosmology without optical depth information

With low-redshift probes reaching unprecedented precision, uncertainty of the cosmic microwave background (CMB) optical depth is expected to be the limiting factor for future cosmological neutrino mass constraints. In this paper, we discuss to what extent combinations of CMB lensing and galaxy survey measurements at low redshifts $z\ensuremath{\sim}0.5--5$ will be able to make competitive neutrino mass measurements without relying on any optical depth constraints. We find that the combination of LSST galaxies and CMB-S4 lensing should be able to achieve constraints on the neutrino mass sum of 25 meV without optical depth information, an independent measurement that is competitive with or slightly better than the constraint of 30 meV possible with CMB-S4 and present-day optical depth measurements. These constraints originate in both structure growth probed by cross-correlation tomography over a wide redshift range as well as, most importantly, the shape of the galaxy power spectrum measured over a large volume. We caution that possible complications such as higher-order biasing and systematic errors in the analysis of high-redshift galaxy clustering are only briefly discussed and may be non-negligible. Nevertheless, our results show that new kinds of high-precision neutrino mass measurements at and beyond the present-day optical depth limit may be possible.

The First Stars: Formation, Properties, and Impact

The first generation of stars, often called Population III (or Pop III), form from metal-free primordial gas at redshifts z ∼ 30 and below. They dominate the cosmic star-formation history until z ∼ 15–20, at which point the formation of metal-enriched Population II stars takes over. We review current theoretical models for the formation, properties, and impact of Pop III stars and discuss existing and future observational constraints. Key takeaways from this review include the following: ▪Primordial gas is highly susceptible to fragmentation and Pop III stars form as members of small clusters with a logarithmically flat mass function.▪Feedback from massive Pop III stars plays a central role in regulating subsequent star formation, but major uncertainties remain regarding its immediate impact.▪In extreme conditions, supermassive Pop III stars can form, reaching masses of several 105M⊙. Their remnants may be the seeds of the supermassive black holes observed in high-redshift quasars.▪Direct observations of Pop III stars in the early Universe remain extremely challenging. Indirect constraints from the global 21-cm signal or gravitational waves are more promising.▪Stellar archeological surveys allow us to constrain both the low-mass and the high-mass ends of the Pop III mass distribution. Observations suggest that most massive Pop III stars end their lives as core-collapse supernovae rather than as pair-instability supernovae.

Future Constraints on Dark Matter with Gravitationally Lensed Fast Radio Bursts Detected by BURSTT

Understanding dark matter is one of the most urgent questions in modern physics. A very interesting candidate is primordial black holes (PBHs). For the mass ranges <10−16 M ⊙ and >100 M ⊙, PBHs have been ruled out. However, they are still poorly constrained in the mass range 10−16–100 M ⊙. Fast radio bursts (FRBs) are millisecond flashes of radio light of unknown origin, mostly from outside the Milky Way. Due to their short timescales, gravitationally lensed FRBs, which are yet to be detected, have been proposed as a useful probe for constraining the presence of PBHs in the mass window of <100 M ⊙. Up to now, the most successful project in finding FRBs has been CHIME. Due to its large field of view, CHIME has detected at least 600 FRBs since 2018. However, none of them is confirmed to be gravitationally lensed. Taiwan plans to build a new telescope, the Bustling Universe Radio Survey Telescope in Taiwan (BURSTT), dedicated to detecting FRBs. Its survey area will be 25 times greater than CHIME. BURSTT can localize all of these FRBs through very long baseline interferometry. We estimate the probability to find gravitationally lensed FRBs, based on the scaled redshift distribution from the latest CHIME catalog and the lensing probability function from Munõz et al. BURSTT-2048 can detect ∼24 lensed FRBs out of ∼1700 FRBs per annum. With BURSTT’s ability to detect nanosecond FRBs, we can constrain PBHs to form a part of dark matter down to 10−4 M ⊙.

A Note on Temporary Supply Shocks with Aggregate Demand Inertia

We study optimal monetary policy during temporary supply contractions when aggregate demand has inertia and the central bank is concerned about future constraints on expansionary policy. In this environment, it is optimal to run the economy hot until supply recovers. However, the policy does not remain loose throughout the low-supply phase. Overall, when the initial aggregate demand is low, the goal is to frontload the rate cuts to raise demand in anticipation of the recovery of supply. If inflation also has inertia, the central bank still overheats the economy during the low-supply phase but gradually cools it down over time. (JEL E12, E21, E23, E31, E43, E52)

Robust Design of Electric Charging Infrastructure Locations under Travel Demand Uncertainty and Driving Range Heterogeneity

The rising demand for electric vehicles (EVs), motivated by their environmental benefits, is generating an increased need for EV charging infrastructure. Also, it has been recognized that the adequacy of such infrastructure helps promote EV use. Therefore, to facilitate EV adoption, governments seek guidance on continued investments in EV charging infrastructure development. Such investment decisions, which include EV charging station locations and capacities, and the timing of such investments require robust estimates of future travel demand and EV battery range constraints. This paper develops and implements a framework to establish an optimal schedule and locations for new charging stations and decommissioning gasoline refueling stations over a long-term planning horizon, considering the uncertainty in future travel demand forecasts and the driving range heterogeneity of EVs. A robust mathematical model is proposed to solve the problem by minimizing not only the worst-case total system travel cost but also the total penalty for unused capacities of charging stations. This study uses an adaptation of the cutting-plane method to solve the proposed model. Based on two key decision criteria (travelers’ cost and charging supply sufficiency), the results indicate that the robust scheme outperforms its deterministic counterpart.

Microbe-Plant Interactions Targeting Metal Stress: New Dimensions for Bioremediation Applications.

In the age of industrialization, numerous non-biodegradable pollutants like plastics, HMs, polychlorinated biphenyls, and various agrochemicals are a serious concern. These harmful toxic compounds pose a serious threat to food security because they enter the food chain through agricultural land and water. Physical and chemical techniques are used to remove HMs from contaminated soil. Microbial-metal interaction, a novel but underutilized strategy, might be used to lessen the stress caused by metals on plants. For reclaiming areas with high levels of heavy metal contamination, bioremediation is effective and environmentally friendly. In this study, the mechanism of action of endophytic bacteria that promote plant growth and survival in polluted soils-known as heavy metal-tolerant plant growth-promoting (HMT-PGP) microorganisms-and their function in the control of plant metal stress are examined. Numerous bacterial species, such as Arthrobacter, Bacillus, Burkholderia, Pseudomonas, and Stenotrophomonas, as well as a few fungi, such as Mucor, Talaromyces, Trichoderma, and Archaea, such as Natrialba and Haloferax, have also been identified as potent bioresources for biological clean-up. In this study, we additionally emphasize the role of plant growth-promoting bacteria (PGPB) in supporting the economical and environmentally friendly bioremediation of heavy hazardous metals. This study also emphasizes future potential and constraints, integrated metabolomics approaches, and the use of nanoparticles in microbial bioremediation for HMs.

Recent Advancements of Polymeric Membranes in Anion Exchange Membrane Water Electrolyzer (AEMWE): A Critical Review.

Water electrolysis coupled with renewable energy is one of the principal methods for producing green hydrogen (or renewable hydrogen). Among the different electrolysis technologies, the evolving anion exchange membrane water electrolysis (AEMWE) shows the utmost promise for the manufacture of green hydrogen in an inexpensive way. In the present review, we highlight the most current and noteworthy achievements of AEMWE, which include the advancements in increasing the polymer anionic conductivity, understanding the mechanism of degradation of AEM, and the design of the electrocatalyst. The important issues affecting the AEMWE behaviour are highlighted, and future constraints and openings are also discussed. Furthermore, this review provides strategies for producing dynamic and robust AEMWE electrocatalysts.

Development and performance of particleboard from various types of organic waste and adhesives: A review

Environmentally friendly or green building materials are more commonly used in the construction industry and furniture making industry. The knowledge of the environmental risks including the depletion of natural resources, the impact of pesticides, as well as the amplifier and enforcement criteria of good practice have led to an increase in the practice of recycling waste materials, and in particular, the recycling of abandoned trees in particleboard production. From the adhesive aspect, in view of future constraints of formaldehyde use, suitable alternatives to formaldehyde-based adhesive systems would have to be developed and implemented in the wood processing industry. The present review represents a critical appraisal of various organic wastes and adhesives used as raw materials in particleboard development. The core of this review is an assessment of physical and mechanical properties of particleboards based on various types of organic waste and adhesive. Based on these data, we evaluated their potential to identify suitable alternative raw materials having a certain probability to meet the requirements of a large-scale industry sector. Characteristics such as density, thickness swelling, modulus of rupture (MOR) and modulus of elasticity (MOE) are significant in the studies carried out by researchers worldwide. However, they also depend on the types of raw materials, adhesives, parameters and indicators used throughout particleboard production. As an overall conclusion, some organic wastes have the potential to replace wood fibers as raw materials in particleboard production with similar performances. Natural-based adhesives have also shown the potential to substitute formaldehyde-based adhesives in terms of performance. However, toxicological investigations should be performed before a decision can been made to ensure they are safe and add value as replacements for formaldehyde-based adhesives.

SU(6) gauge-Higgs grand unification: minimal viable models and flavor

Gauge-Higgs grand unification theories are models of gauge-Higgs unification that extend the electroweak group into a simple group that includes the color symmetry. The minimal option is a gauge-Higgs grand unification based on the SU(6) gauge group, mirroring SU(5) grand unification in 4D while providing a solution to the hierarchy problem. We explore different minimal and realistic novel incarnations of SU(6) gauge-Higgs grand unification. We submit the setup to the various flavor hierarchies observed in nature and, utilizing the power of the fifth dimension, identify an embedding that provides a compelling model of quarks and leptons that naturally explains the mass hierarchies and the CKM/PMNS structure. We perform a detailed study of quark- and lepton-flavor constraints (which are intimately related due to the GUT nature) together with an analysis of the Higgs potential which arises at the loop level. Electroweak precision constraints on the model are discussed and the rich scalar sector is analyzed. Future flavor constraints from upcoming experiments will provide a stringent test for this class of models, while a scalar singlet and leptoquark provide unique targets for current and future collider experiments to probe this solution to various open questions in nature.