Improved computational treatment of transonic flow about swept wings

Relaxation solutions to classical three-dimensional small-disturbance (CSD) theory for transonic flow about lifting swept wings are reported. For such wings, the CSD theory was found to be a poor approximation to the full potential equation in regions of the flow field that are essentially two-dimensional in a plane normal to the sweep direction. The effect of this deficiency on the capture of embedded shock waves in terms of (1) the conditions under which shock waves can exist and (2) the relations they must satisfy when they do exist is emphasized. A modified small-disturbance (MSD) equation, derived by retaining two previously neglected terms, was proposed and shown to be a consistent approximation to the full potential equation over a wider range of sweep angles. The effect of these extra terms is demonstrated by comparing CSD, MSD, and experimental wing surface pressures

Gauge invariant generalization of the 2D chiral Gross-Neveu model

By means of the Lee-Shrock transformation we generalize the 2D Gross-Neveu (GN$_2$) model to a U(1) gauge theory with charged fermion and scalar fields in 2D ($\chi U \phi_2$ model). The $\chi U \phi_2$ model is equivalent to the GN$_2$ model at infinite gauge coupling. We show that the dynamical fermion mass generation and asymptotic freedom in the effective four-fermion coupling persist also when the gauge coupling decreases. These phenomena are not influenced by the XY$_2$ model phase transition at weak coupling. This suggests that the $\chi U \phi_2$ model is in the same universality class as the GN$_2$ model and thus renormalizable.Comment: Contribution to Lattice 95, LaTeX file (4 pages), 4 ps-figures appended (uuencoded), abstract correcte

Design Requirements for AI-based Services Enriching Legacy Information Systems in Enterprises: A Managerial Perspective

Information systems (IS) have been introduced in enterprises for decades to generate business value. Historically systems that are deeply integrated into business processes and not replaced remain vital assets, and thus become legacy IS (LISs). To secure the future success, enterprises invest in innovative technologies such as artificial intelligence-based services (AIBSs), enriching LISs and assisting employees in the execution of work-related tasks. This study develops design requirements from a managerial perspective by following a mixed-method approach. First, we conducted ten interviews to formulate requirements to design AIBSs. Second, we evaluated their business value using an online survey (N = 101). The results indicate that executives consider design requirements as relevant that create strategic advancements in the short term. With the help of our findings, researchers can better understand where further in-depth studies are needed to refine the requirements. Practitioners can learn how AIBSs generate business value when enriching LISs

Towards Successful Collaboration: Design Guidelines for AI-based Services enriching Information Systems in Organisations

Information systems (IS) are widely used in organisations to improve business performance. The steady progression in improving technologies like artificial intelligence (AI) and the need of securing future success of organisations lead to new requirements for IS. This research in progress firstly introduces the term AI-based services (AIBS) describing AI as a component enriching IS aiming at collaborating with employees and assisting in the execution of work-related tasks. The study derives requirements from ten expert interviews to successful design AIBS following Design Science Research (DSR). For a successful deployment of AIBS in organisations the D&M IS Success Model will be considered to validated requirements within three major dimensions of quality: Information Quality, System Quality, and Service Quality. Amongst others, preliminary findings propose that AIBS must be preferably authentic. Further discussion and research on AIBS is forced, thus, providing first insights on the deployment of AIBS in organisations

Modern secondary cooling technology in continuous casting of steel

Continuous casting machines are now required to cast a wide range of steel grades while maximising production output. Consistent production of prime quality product requires increased operational and maintenance flexibility of the caster so that the optimum casting parameters can be maintained for each steel grade. This flexibility extends not only to the machine elements and control systems, but also to the secondary cooling system and demands more efficient and reliable spray cooling. Attentive design of secondary cooling systems, through cooling zone positioning, nozzle layout, nozzle selection and the use of appropriate secondary cooling control systems can provide these requirements. Minimum down time for maintenance is a key factor in maximising caster production; the use of the latest piping header systems and nozzle mounting arrangements can contribute to minimum secondary cooling maintenance. These header systems provide a rigid and self-aligning mounting for the nozzle, ensuring both nozzle alignment and maintenance accessibility

Insight into Protein–Polymer Conjugate Relaxation Dynamics: The Importance of Polymer Grafting

The bio and chemical physics of protein–polymer conjugates are related to parameters that characterize each component. With this work, it is intended to feature the dynamical properties of the protein–polymer conjugate myoglobin (Mb)–poly(ethyl ethylene phosphate), in the ps and ns time scales, in order to understand the respective roles of the protein and of the polymer size in the dynamics of the conjugate. Elastic and quasi-elastic neutron scattering is performed on completely hydrogenated samples with variable number of polymer chains covalently attached to the protein. The role of the polymer length in the protein solvation and internal dynamics is investigated using two conjugates formed by polymers of different molecular weight. It is confirmed that the flexibility of the complex increases with the number of grafted polymer chains and that a sharp dynamical transition appears when either grafting density or polymer molecular weight are high. It is shown that protein size is crucial for the polymer structural organization and interaction on the protein surface and it is established that the glass properties of the polymer change upon conjugation. The results give a better insight of the equivalence of the polymer coating and the role of water on the surface of proteins

Multiple-scattering effects on incoherent neutron scattering in glasses and viscous liquids

Incoherent neutron scattering experiments are simulated for simple dynamic models: a glass (with a smooth distribution of harmonic vibrations) and a viscous liquid (described by schematic mode-coupling equations). In most situations multiple scattering has little influence upon spectral distributions, but it completely distorts the wavenumber-dependent amplitudes. This explains an anomaly observed in recent experiments