New Set Of Conditions Research Articles

Improved delay-dependent stability analysis of digital filters with generalized overflow arithmetic

This paper introduces a new set of conditions that establish Input-to-State Stability (ISS) for digital filters with external disturbance input and time-varying delays, all within the context of generalized overflow arithmetic. A unique augmented Lyapunov function and a novel summation inequality are applied to formulate a new criterion for ISS. This criterion assesses the ISS of digital filters in the presence of external disturbance, enabling the identification of asymptotic stability even in the absence of such disturbance. The criteria are developed using linear matrix inequalities (LMIs). The efficacy of the results is demonstrated through three numerical examples, highlighting that the proposed criteria are less conservative than some recent results.

Out of Order

Now hegemony is ending, and multipolarity has become real. Yet it is not actually an international order, but merely a new set of conditions under which states must operate. And it is not yet clear whether order is, in principle, possible under these conditions.

Event-triggered finite-time admissibilization of bio-economic singular semi-Markovian jump fuzzy systems

An event-triggered scheme-based admissibilization problem of bio-economic singular semi-Markovian jump systems over a finite-time interval is investigated in this study, where the commodity price is assumed to follow a semi-Markov process. To facilitate analysis, the addressed system is expressed using Takagi-Sugeno fuzzy modeling with two fuzzy rules, which is then generalized to a finite number of fuzzy rules. Following that, an affine membership-based event-triggered controller is proposed for the system under consideration to ensure the desired admissibility within a given finite-time interval. A new set of conditions that adequately guarantees the aforementioned problem is derived using the Lyapunov-Krasovskii stability theory, parameterized linear matrix inequality technique and dissipative theory. A numerical example based on the eel seedling harvesting model is considered to validate the developed theoretical findings, where the significance of the proposed control design method is clearly demonstrated.

Scaling up an Electrochemical Nitrogen Recovery Process from Lab Benchtop to Pilot Wastewater Plant

Municipal wastewater and agricultural runoff contain large amounts of reactive nitrogen, which can pollute the environment upon release, leading to harmful algal blooms and poor drinking water quality. At the same time, these reactive nitrogen species are valuable and can be recycled to generate fertilizers and commodity chemicals; it has been estimated that doing so would offset the need for ~30% of global Haber-Bosch ammonia production. For this reason, both removal and recovery of active nitrogen from wastewaters are important goals. An electrochemical separations technique known as Electrochemical Stripping (ECS) has been developed to achieve selective ammonia recovery from wastewater.1 This technique leverages pH swings induced by water-splitting, coupled with appropriate cation- and gas-selective membranes, to remove and recover ammonia nitrogen from wastewaters. ECS has been demonstrated at the benchtop scale with relatively high efficiency (>90% total ammonia nitrogen [TAN] recovery) in various wastewaters, and the effects of certain process variables such as temperature, influent TAN concentration, and gas-permeable membrane material have previously been reported.2 Our goal with this work is to initiate ECS process scale-up by at least 3 orders of magnitude in order to match the scale of municipal wastewater treatment. In order to do this, we set out to build a more complete fundamental process model to inform our design decisions during scale-up. Here we will present results of exploratory tests varying multiple process parameters, including current density, relative electrolyte volumes, reactor residence time, catholyte solution chemistry, and reactor geometry. We then translate these results into a process model comprising thermodynamic relationships as well as kinetic equations, describing both the rates of species generation/consumption as well as transport between reactor compartments. This model, which yields molecular-level insights, is then used in an iterative fashion to first predict performance at small scales under new sets of conditions, and then ultimately inform the design of a ~1000 L/day ECS reactor at a pilot-scale wastewater treatment facility.In addition, we will discuss findings from stakeholder engagement conducted in parallel to lab-scale tests, indicating utility limitations, priorities, needs for certain effluent specs, desired product specs, cost bounds, and details around hydrogen coproduct handling. These discussions additionally feed into design decisions and are crucial for eventual technology deployment.

Lévy-type solutions for the buckling analysis of unsymmetrically laminated plates with rotational restraints for various plate theories

The stability behaviour of unsymmetrical laminated structures made of fibre-reinforced plastics is significantly influenced by bending–extension coupling and the comparatively low transverse shear stiffnesses. The aim of this work is to improve the analytical stability analysis of unsymmetrically laminated structures. With the discrete plate theory, the stability of laminated structures can be reduced to single laminated plates. The structure is divided into individual segments, and the surrounding structure is modelled by rotational elastic restraints. The governing equations for single plates under specific boundary conditions can be solved exactly with Lévy-type solutions. In this study, Lévy-type solutions for the mentioned boundary conditions under biaxial compressive load is described for the classical laminated plate theory, the first-order shear deformation theory and the third-order shear deformation theory (TSDT). In addition to transverse shear, bending–extension couplings of unsymmetrical cross-ply and antisymmetrical angle-ply laminates are considered. For the implementation of boundary conditions for the rotational restraints in the context of TSDT, a new set of conditions is formulated. The investigation shows very good agreement of the buckling load with comparative finite element analyses for different layups.

Exponential state estimate of positive systems with time-varying delays: a Lyapunov–Razumikhin approach

AbstractIn this paper, for the first time, a linear Lyapunov–Razumikhin function is introduced to find an $\alpha$-exponential state estimate for positive systems with time delays. A new set of conditions for the existence of exponential state boundedness of positive systems with bounded time-varying delays is established. Two procedures are then proposed to find the factor vector of $\alpha$-exponential state estimate, in which some techniques of optimization are applied to find the smallest possible factor vector. Numerical experiments are presented to demonstrate the effectiveness of the linear Lyapunov–Razumikhin function as well as of the optimization techniques.

Masing Manifolds: Reconciling the Masing Conditions with Real Hysteresis in Jointed Structures

The Masing conditions establish a criterion to relate the loading curve of a hysteretic system (e.g., systems with friction or plasticity) to its complete hysteresis loop. For the field of joint mechanics, where hysteretic models are often used to describe the dissipative, tangential behavior within an interface, the Masing conditions allow for significant computational savings when the normal load is constant. In practice, though, jointed systems experience time varying normal forces that modify the tangential behavior of the system. Consequently, the hysteretic behavior of jointed structures do not adhere to the Masing conditions. In this work, this discrepancy between the Masing conditions and behavior exhibited by jointed structures is explored, and it is hypothesized that if the Masing conditions accounted for variations in normal force, then they would more accurately represent jointed structures. A new set of conditions is introduced to the original set of Masing conditions, yielding a « Masing manifold » that spans the tangential displacement-tangential force-normal force space. Both a simple harmonic oscillator and a built-up structure are investigated for the case of elastic dry friction, and the results show that the hysteresis of both of these systems conforms to the three dimensional Masing manifold exactly, provided that a set of constraints are satisfied, even though the hysteresis does not conform with the original Masing conditions.

Can we expect re-emergence of infectious diseases in the near future?

Ever since Hippocrates expressed the view that environmental factors can influence disease incidence, attempts have been made to link the emergence of disease, especially outbreaks of infectious diseases, with the various factors that contribute to their occurrence. Among the possible causes favoring the spread of pathogens and the increase in the incidence of infectious diseases, environmental and social conditions are mentioned. An unprecedented set of new conditions has made the human population more vulnerable and more susceptible to infectious diseases than ever before. It is possible that the observed contemporary patterns of development and spread of infectious diseases may be seen as heralds of a new stage of epidemiological transformation characterized by an increased risk of infectious disease epidemics. In past centuries, one of the hallmarks of infectious disease plagues has been their unpredictability. Currently, warning forecasts prepared by scientists do not always translate into preventive measures.

Desymmetric Partial Reduction of Malonic Esters

Desymmetrization of easily available disubstituted malonic esters is a rewarding strategy to access structurally diverse quaternary stereocenters. Particularly, asymmetric reduction of malonic esters would generate a functional group with a lower oxidation state than the remaining ester, thus allowing for more chemoselective derivatization. Here, we report a new set of conditions for the zinc-catalyzed desymmetric hydrosilylation of malonic esters that afford aldehydes as the major product. Compared with alcohol-selective desymmetrization, the partial reduction uses a higher concentration of silanes and new pipecolinol-derived tetradentate ligands, proposedly to switch the pathway of zinc hemiacetal intermediates from elimination to silylation. As a result, high aldehyde-to-alcohol ratios and enantioselectivity of aldehydes are obtained from malonic esters with a large collection of substituents. Together with the abundant reactivity of aldehydes, the partial reduction has enabled an expeditious synthesis of bioactive compounds and natural metabolites containing a quaternary stereocenter.

Activity patterns and behavior of Myocastor coypus in a gated community in the metropolitan area of Buenos Aires (Argentina)

Abstract Anthropization processes confront local wildlife with a new set of conditions that may lead to local extinctions or allow the expansion of some species. This is what happens with the coypu (Myocastor coypus) in gated communities in the metropolitan area of Buenos Aires (Argentina), where its rapid population growth results in continuous conflicts with the local inhabitants. The aim of this study was to document the daily and seasonal activity patterns and behavior of the coypu in an urban landscape within their natural distribution range. To achieve this, we conducted a camera-trap survey within areas occupied by the species from February to November 2018. The coypu activity was mainly crepuscular and nocturnal with variations between seasons. We found that the seasons with the greatest activity patterns overlap were winter and autumn (84%), while the least overlap was observed between summer and winter (53%). During the active periods, time spent on foraging behavior was dominant. Time dedicated to vigilance was greater in summer than in winter. This result, alongside an increase in nocturnal activity during summer, shows that coypu in this urban landscape shift its behavior when exposed to an increasing human activity. This study brings up more ecological data of this species, which is key to find alternative control methods within gated communities to lead to a harmonic relationship between inhabitants and the species in its native distribution.

A different view on (world) heritage. The need for multi-perspective data analyses in historical landscape studies: The example of Schokland (NL)

The awareness that cultural heritage plays an influential role in shared identities and in both spatial and environmental development has significantly increased in recent years. International collaboration and treaties, such as the ‘FARO-convention’ in 2005 emphasize the importance of heritage in relation to aspects of human rights and demography. Furthermore, it is becoming increasingly clear that historical perspectives are essential for making well-informed choices regarding environmental challenges (e.g. spatial planning, sustainable development, climate adaptation). This increased awareness not only emphasizes the importance of cultural heritage for present-day challenges, but equally presents a new set of conditions and standards, and requires the development of new methodologies. Besides conservation, more than ever there is a need for cultural heritage to become contextualized and sustainably accessible. The organisational pinnacle of cultural-heritage conservation is world heritage: sites that are judged to contain a set of cultural and/or natural values which are of outstanding value to humanity. However, to what extent world heritage meets these newly set criteria is unknown. Nevertheless, these sites often reflect an eminent status, scientifically as well as economically (i.e. through tourism). Consequently, world heritage often enjoys interest from multiple stakeholders including governmental, scientific, public, and commercial parties, all of whom engage in contrasting activities and have different interests and needs. As a result the need for accessibility and integrated overviews of these sites is high but equally challenging. In this paper we will focus on the world-heritage site of Schokland (NL). This former island in the Dutch Zuiderzee both reflects outstanding historical and archaeological importance. We will show that the dynamics surrounding this site require tailormade conservation methodologies, which greatly depend on data integration. We present a new Historical Geographical Information System (HGIS) specifically designed to integrate cultural and geoscientific data and facilitate dynamic heritage management. Results show that such a system greatly adds to the contextualization and (digital) accessibility of the heritage site and is essential for substantiating conservation methodologies. Furthermore, it shows great research potential for diachronological reconstructions of dynamic-lowland development. The system facilitates multidisciplinary scientific analyses, integrated monitoring, and public outreach and shows great application potential for other (world-)heritage sites.

Variability of plasmid fitness effects contributes to plasmid persistence in bacterial communities

Plasmid persistence in bacterial populations is strongly influenced by the fitness effects associated with plasmid carriage. However, plasmid fitness effects in wild-type bacterial hosts remain largely unexplored. In this study, we determined the fitness effects of the major antibiotic resistance plasmid pOXA-48_K8 in wild-type, ecologically compatible enterobacterial isolates from the human gut microbiota. Our results show that although pOXA-48_K8 produced an overall reduction in bacterial fitness, it produced small effects in most bacterial hosts, and even beneficial effects in several isolates. Moreover, genomic results showed a link between pOXA-48_K8 fitness effects and bacterial phylogeny, helping to explain plasmid epidemiology. Incorporating our fitness results into a simple population dynamics model revealed a new set of conditions for plasmid stability in bacterial communities, with plasmid persistence increasing with bacterial diversity and becoming less dependent on conjugation. These results help to explain the high prevalence of plasmids in the greatly diverse natural microbial communities.

Disasters as Catalysts for Energy Transition

The concept of disaster as a positive force for change seems intuitive, but is covered only occasionally in the energy transition literature. We review disaster risk and recovery literature to assess how these types of transformations may be different, and provide a change pathway within the popular Multi-Level Perspective framework. While incumbent systems are, by definition, stable (making change difficult), disaster can override these challenges by providing simultaneous disruption at all structure levels. By exceeding the capacity of the regime and its established processes and practices, disaster provides an opportunity to reformat social structures through reconstruction and recovery processes. Importantly, significant disruption has the ability to plasticize the landscape for a short timeframe, with potential change within a finite deviation from existing trends. During this disruptive period, the regime and landscape become co-dependent, with any meso-level void filled by a combination of new and reconstructed fragments, working to restore the stability of the foundation. The new regime must then satisfy the resultant set of socially dictated conditions set by the revised landscape to maintain the new structure. The challenge then is not to be restrained by the swift recovery of the previous regime, and to form a new set of conditions to deliver improved outcomes that better balance the needs of natural and anthropogenic systems.

Dialkyl Ether Formation at High-Valent Nickel.

In this article, we investigated the I2-promoted cyclic dialkyl ether formation from 6-membered oxanickelacycles originally reported by Hillhouse. A detailed mechanistic investigation based on spectroscopic and crystallographic analysis revealed that a putative reductive elimination to forge C(sp3)–OC(sp3) using I2 might not be operative. We isolated a paramagnetic bimetallic NiIII intermediate featuring a unique Ni2(OR)2 (OR = alkoxide) diamond-like core complemented by a μ-iodo bridge between the two Ni centers, which remains stable at low temperatures, thus permitting its characterization by NMR, EPR, X-ray, and HRMS. At higher temperatures (>−10 °C), such bimetallic intermediate thermally decomposes to afford large amounts of elimination products together with iodoalkanols. Observation of the latter suggests that a C(sp3)–I bond reductive elimination occurs preferentially to any other challenging C–O bond reductive elimination. Formation of cyclized THF rings is then believed to occur through cyclization of an alcohol/alkoxide to the recently forged C(sp3)–I bond. The results of this article indicate that the use of F+ oxidants permits the challenging C(sp3)–OC(sp3) bond formation at a high-valent nickel center to proceed in good yields while minimizing deleterious elimination reactions. Preliminary investigations suggest the involvement of a high-valent bimetallic NiIII intermediate which rapidly extrudes the C–O bond product at remarkably low temperatures. The new set of conditions permitted the elusive synthesis of diethyl ether through reductive elimination, a remarkable feature currently beyond the scope of Ni.

A NOTE ON DERIVABILITY CONDITIONS

AbstractWe investigate relationships between versions of derivability conditions for provability predicates. We show several implications and non-implications between the conditions, and we discuss unprovability of consistency statements induced by derivability conditions. First, we classify already known versions of the second incompleteness theorem, and exhibit some new sets of conditions which are sufficient for unprovability of Hilbert–Bernays’ consistency statement. Secondly, we improve Buchholz’s schematic proof of provable $\Sigma_1$ -completeness. Then among other things, we show that Hilbert–Bernays’ conditions and Löb’s conditions are mutually incomparable. We also show that neither Hilbert–Bernays’ conditions nor Löb’s conditions accomplish Gödel’s original statement of the second incompleteness theorem.

High-dimensional limits of eigenvalue distributions for general Wishart process

In this article, we obtain an equation for the high-dimensional limit measure of eigenvalues of generalized Wishart processes, and the results are extended to random particle systems that generalize SDEs of eigenvalues. We also introduce a new set of conditions on the coefficient matrices for the existence and uniqueness of a strong solution for the SDEs of eigenvalues. The equation of the limit measure is further discussed assuming self-similarity on the eigenvalues.

On the Improved Rates of Convergence for Matérn-Type Kernel Ridge Regression with Application to Calibration of Computer Models

Kernel ridge regression is an important nonparametric method for estimating smooth functions. We introduce a new set of conditions under which the actual rates of convergence of the kernel ridge re...

Average Cost Optimality Inequality for Markov Decision Processes with Borel Spaces and Universally Measurable Policies

We consider average-cost Markov decision processes (MDPs) with Borel state and action spaces and universally measurable policies. For the nonnegative cost model and an unbounded cost model with a Lyapunov-type stability character, we introduce a set of new conditions under which we prove the average cost optimality inequality (ACOI) via the vanishing discount factor approach. Unlike most existing results on the ACOI, our result does not require any compactness and continuity conditions on the MDPs. Instead, the main idea is to use the almost-uniform-convergence property of a pointwise convergent sequence of measurable functions as asserted in Egoroff's theorem. Our conditions are formulated in order to exploit this property. Among others, we require that for each state, on selected subsets of actions at that state, the state transition stochastic kernel is majorized by finite measures. We combine this majorization property of the transition kernel with Egoroff's theorem to prove the ACOI.

Municipal Solid Waste as a valuable recycled asset for small-scale electricity production in rural communities

Municipal solid waste provides an opportunity for electricity production. This strategy provides the rural communities a potential waste-to-energy opportunity to manage its costly residues problem, turning them into a valuable recycled asset. To address this issue, a techno-economic study of an integrated system comprising gasification of Acacia residues and Portuguese Municipal Solid Waste (PMSW) with an Internal Combustion Engine-Generator (ICEG) for electricity generation at small-scale (100 kW) was developed. Current studies only devote attention to biomass residues and do not explore MSW potential to eschew biomass supply shortage. Conventional systems are generally part of biomass supply chains, limiting flexibility and all year operation for their operators. Experimental data was gathered at a downdraft gasifier to provide a clear assessment of particle and tar concentration in the syngas and levers conditioning a satisfactory ICE operation. Once the potential of using Acacia residues and PMSW has been proven during gasification runs testing, and validation, a set of new conditions was also explored through a high-fidelity CFD model. We find that residues blends have the highest potential to generate high-quality syngas and smallest exposure to supply disruption. Despite both substrates showing potential at specific conditions, they also present individual drawbacks which will be best mitigated by executing a hybrid supply comprising the mix of substrates. An economic model coupling the financial indicators of net present value (NPV), internal rate of return (IRR) and the payback period (PBP) considering a project lifetime of 25 years was developed. Cost factors include expenses with electricity generation, initial investment, amortizations and operation and maintenance (containing fuels costs). Revenues were estimated from electricity generated and sales to the national grid. A sensitivity analysis based on the Monte Carlo method was used to measure the economic model performance and to determine the risk in investing in such venture. The risk appraisal yielded favorable investment projections, with an NPV reaching positive values, an IRR superior to the discount rate and PBP lower than the project life span. This work allowed to confirm the positive effect of the generation of energy from downdraft gasification plants on a small-scale. Regardless of the project’s feasibility, the economic performance depended to a large extent on the electricity prices which present considerable variability and are subject to political decisions.

Electrochemical Atomic Layer Deposition of CuInSe2 on Au Surface

CuInSe2 (CIS) thin film growth on Au/glass slide surface was investigated by electrochemical atomic layer deposition (E‐ALD) in superlattice sequence in ambient laboratory conditions without any heat treatment processes involved. The electrochemical behavior of Cu, In, and Se on the Au surface was surveyed, the underpotential deposition phenomena of In was demonstrated for the first time and a various set of potentials for the three elements were considered to fabricate thin CIS films by specific superlattice sequencing. The crystal structure, elemental composition, topography, and photoelectrochemical behavior of each film produced were evaluated with the aim of finding a new set of conditions for producing stoichiometric CIS films. A good stoichiometric film of Cu0.99In0.98Se2.00 was successfully prepared by applying 50 periods of the superlattice sequence of 3(In aSe b) + 1(Cu cSe d) with the new deposition potentials of 0.08, −0.55, and −0.05 V for Cu, In, and Se precursor solutions, respectively. The resulting E‐ALD film was found to exhibit a p‐type semiconductivity.