Recommending metamodel concepts during modeling activities with pre-trained language models

Software and Systems Modeling - The design of conceptually sound metamodels that embody proper semantics in relation to the application domain is particularly tedious in model-driven engineering....     

A combinatorial approach to a class of parallel-machine,continuous-time scheduling problems

The paper analyzes a manufacturing system with N non-identical, parallel machines continuously producing one product type in response to its demand. Inventory and backlog costs are incurred when tracking the demand results in inventory surpluses and shortages respectively. In addition, the production cost of a machine is incurred when the machine is not idle. The objective is to determine machine production rates so that the inventory, backlog, and production costs are minimized. For problems with demand defined as an arbitrary function of time, numerical methods are suggested to approximate an optimal solution. The complexity of the approximation methods is polynomial, while finding an exact optimal solution requires exponential time. In a case when production is to cope with a special form of a single-mode, K-level piece-wise constant demand, we prove, with the aid of the maximum principle, that the exact optimal solution can be found as a combination of analytical and combinatorial tools in O(KN ²( max {K,2N})²) time.     

Complex RNA-DNA hybrid nanoshapes from iterative mix-and-match screening

Hybrid nucleic acid nanostructures partition architectural and functional roles between ribonucleic acid(RNA)joints and deoxyribonucleic acid(DNA)connectors.Nanoshapes self-assemble from nucleic acid modules through synergistic stabilization of marginally stable base pairing interactions within circularly closed polygons.Herein,we report the development of hybrid nanoshapes that include multiple different RNA modules such as internal loop and three-way junction(3WJ)motifs.An iterative mix-and-match screening approach was used to identify suitable DNA connectors that furnished stable nanoshapes for combinations of different RNA modules.The resulting complex multicomponent RNA-DNA hybrid nanoshapes were characterized by atomic force microscopy(AFM)imaging.Our research provides proof of concept for modular design,assembly and screening of RNA-DNA hybrid nanoshapes as building blocks for complex extended nucleic acid materials with features at the sub-10 nm scale.     

The set of lagrange and routh formulations for non-linear networks

Formulations of systems of Lagrange and Routh equations for arbitrary non-linear electrical circuits are given. the use of Routh equations for this purpose is new. It is proved that these formulations are equivalent to the complete system of Kirchhoff equations (instead of only a part of it as in prior works). the vector of generalized coordinates for the system of Lagrange equations consists of four subvectors (loop charges for fundamental loops, cut-set fluxes for fundamental cut-sets, branch fluxes for voltage and flux controlled elements and branch charges for current and charge controlled elements). For the defined set of Lagrange formulations, the uniqueness of a parametric representation is proved. the structure of the Lagrange (Hamilton, Routh) formulation set is then studied and it is proved that this set is an Abelian group. A duality of Lagrange triples for electrically and topologically dual circuits is established and it is proved that this relation between the sets of Lagrange triples is an isomorphism. It is also shown that the Brayton-Moser equations and the anti-Lagrangian equations similar to those of M. Mili? and L. Novak represent partial cases of the formulated set.     

Interactions of Cold Radiofrequency Plasma with Solid Wood I. Nitrogen Permeability along the Grain

Exposure of 1.5 cm diameter × 1.2 cm long white fir and Douglas-fir heart-and sapwood samples to the action of cold radiofrequency oxygen, nitrogen, and helium plasmas strongly increased wood permeability to nitrogen flow along the grain. Oxygen was most effective, followed by nitrogen and helium. While an increase in radiofrequency energy level increased the effect, the opposite was true for an increase in reactant gas flow rate. With white fir the rate of permeability increase was higher at the beginning of the plasma treatment. This was attributed to differing ablation rates of cellulose, hemicelluloses, and lignin. No significant time difference in the rate of permeability increase was observed with Douglas-fir. Extractives suppressed the plasmainduced permeability increase; thus extraction with water and ethanol, followed by oxygen plasma treatment increased permeability of Douglas-fir heartwood 32 times, while plasma treatment of the unextracted Douglas-fir increased permeability only 8 times. The permeability of extracted and oxygen plasma-treated wood did not vary much across the grain, but did decrease with distance from the ends of the samples due to incomplete removal of extractives from the center.     

Analysis of dietary interventions. A simple payoff matrix for display of comparative dietary trials

Objective  

To provide a simple method for presentation of data in comparative dietary trials.     

Dielectric Constant and Optical Reflectance of Ceramic Filler-Added BaO–ZnO–B2O3–P2O5 Glass Composites

This study examined the influence of the addition of ceramic fillers (up to 20 wt% of TiO₂, Al₂O₃, and ZnO, respectively) to a BaO–ZnO–B₂O₃–P₂O₅ glass matrix on the dielectric and optical properties with the aim of using this material as the barrier ribs in plasma display panels. The modification of the dielectric constant by the fillers was related to the formation of secondary phases, the changes in the glass composition by the partial dissolution of the fillers, and the presence of pores. The reflectance of the composites ranged from 60% to 80% with the addition of 20 wt% filler.     

Ballistic performance of armour ceramics: Influence of design and structure. Part 1

The use of advanced ceramics for armour systems allows the defeating of the projectile and ballistic impact energy dissipation providing adequate ballistic protection. The development of lightweight and inexpensive ceramics and armour designs is under ongoing attention by both ceramic armour manufacturers and armour users. This paper summarizes the results of extensive studies of ballistic performance of different armour ceramics, mostly obtained during development, as well as of the materials manufactured by other recognized armour ceramic suppliers, and the designed ceramic-based armour systems. The studied armour ceramics include homogeneous oxide and carbide ceramics and heterogeneous ceramic materials. Composition, structure and main properties of the considered ceramics, which affect ballistic performance, are examined and analyzed. Only a combination of all relevant physical properties and microstructure, including the ability to dissipate ballistic energy, as well as optimization of manufacturing processes, should be considered for proper selection and evaluation of ceramic armour. Ballistic performance of the studied ceramics as function of their structure and properties, armour system design and type of projectile has been discussed.     

Phase Constitution and Dynamic Properties of Spark Plasma‐Sintered Alumina–Titanium Composites

Al₂O₃/Ti composites of various metal to ceramic ratios were fabricated by the spark plasma sintering (SPS) technique. The effects of titanium concentration in the initial mixture on phase composition, and on the static and dynamic (planar impact testing) mechanical properties of the SPS‐processed composites were investigated. It was observed that the significant alumina dissolution in titanium takes place during SPS treatment. The composites fabricated from starting alumina/titanium powder mixtures with a mass fraction of titanium less than 0.8 consisted of two phases, alumina and a solid solution of oxygen and aluminum in titanium. For starting mixtures with higher titanium content, the presence of a Ti₃Al intermetallic phase with a relatively low fraction of dissolved oxygen was detected. Changes in phase composition could explain the effect of titanium content in the starting mixture on physical and mechanical properties of the composites. Mechanisms governing the dynamic response of the composites under loading of different intensities are discussed.