Transport on flexible Rydberg aggregates using circular states

Assemblies of interacting Rydberg atoms show promise for the quantum simulation of transport phenomena, quantum chemistry and condensed matter systems. Such schemes are typically limited by the finite lifetime of Rydberg states. Circular Rydberg states have the longest lifetimes among Rydberg states but lack the energetic isolation in the spectrum characteristic of low angular momentum states. The latter is required to obtain simple transport models with few electronic states per atom. Simple models can however even be realized with circular states, by exploiting dipole-dipole selection rules or external fields. We show here that this approach can be particularly fruitful for scenarios where quantum transport is coupled to atomic motion, in adiabatic excitation transport or quantum simulations of electron-phonon coupling in light harvesting. Additionally, we explore practical limitations of flexible Rydberg aggregates with circular states and to which extent interactions among circular Rydberg atoms can be described using classical models.Comment: 9 Pages, 5 Figure

Interfacial shear in adiabatic downward gas/liquid co-current annular flow in pipes

Interfacial friction is one of the key variables for predicting annular two-phase flow behaviours in vertical pipes. In order to develop an improved correlation for interfacial friction factor in downward co-current annular flow, the pressure gradient, film thickness and film velocity data were generated from experiments carried out on Cranfield University’s Serpent Rig, an air/water two-phase vertical flow loop of 101.6 mm internal diameter. The air and water superficial velocity ranges used are 1.42–28.87 and 0.1–1.0 m/s respectively. These correspond to Reynolds number values of 8400–187,000 and 11,000–113,000 respectively. The correlation takes into account the effect of pipe diameter by using the interfacial shear data together with dimensionless liquid film thicknesses related to different pipe sizes ranging from 10 to 101.6 mm, including those from published sources by numerous investigators. It is shown that the predictions of this new correlation outperform those from previously reported studies

Offshore Topside Rotating Packed Bed as Process Intensified Alternative for Natural Gas Sweetening and Dehydration

This work is aimed at investigating the benefits of replacing conventional process unit operations with process intensified ones in offshore applications. This ensures that better use is made of raw materials, lower energy consumption and a reduced plant volume was achieved. Specifically, a rotating packed bed technology has been used for gas dehydration and sweetening. To achieve the aim of this study, a process intensification approach is used to redesign mature absorption processes to more compact and efficient one. Process simulation using Aspen Hysys was carried out for Triethylene glycol dehydration and monoethanolamine sweetening. More than 36-fold absorption unit size reduction was achieved thereby effecting large decrease in capital and operating costs compared to the conventional packed columns currently utilized in the offshore oil and gas industry. The process intensified technologies therefore can be deployed for offshore applications where space and size considerations are of utmost importance

Developing Oral Communication Skills through Collaborative Learning: Implications for Nigerian Teachers

Considering the need for effective oral communication skills in academic and professional successes, this paper reviews oral communication skills and collaborative learning. It highlights some benefits of collaborative learning. Specifically, it discusses how to develop students' oral communication skills through collaborative learning. Finally, the paper suggests that empirical studies should be conducted to provide teachers with methods that would allow students to collaborate in the learning process in order develop their oral communication skills. It also gives some pedagogical implications for teachers

Quasi-potential landscape in complex multi-stable systems

Developmental dynamics of multicellular organism is a process that takes place in a multi-stable system in which each attractor state represents a cell type and attractor transitions correspond to cell differentiation paths. This new understanding has revived the idea of a quasi-potential landscape, first proposed by Waddington as a metaphor. To describe development one is interested in the "relative stabilities" of N attractors (N>2). Existing theories of state transition between local minima on some potential landscape deal with the exit in the transition between a pair attractor but do not offer the notion of a global potential function that relate more than two attractors to each other. Several ad hoc methods have been used in systems biology to compute a landscape in non-gradient systems, such as gene regulatory networks. Here we present an overview of the currently available methods, discuss their limitations and propose a new decomposition of vector fields that permit the computation of a quasi-potential function that is equivalent to the Freidlin-Wentzell potential but is not limited to two attractors. Several examples of decomposition are given and the significance of such a quasi-potential function is discussed.Comment: 30 pages, 6 figure

Gas/liquid flow behaviours in a downward section of large diameter vertical serpentine pipes

An experimental study on air/water flow behaviours in a 101.6 mm i.d. vertical pipe with a serpentine configuration is presented. The experiments are conducted for superficial gas and liquid velocities ranging from 0.15 to 30 m/s and 0.07 to 1.5 m/s, respectively. The bend effects on the flow behaviours are significantly reduced when the flow reaches an axial distance of 30 pipe diameters or more from the upstream bend. The mean film thickness data from this study has been used to compare with the predicted data using several falling film correlations and theoretical models. It was observed that the large pipe data exhibits different tendencies and this manifests in the difference in slope when the dimensionless film thickness is plotted as a power law function of the liquid film Reynolds number

Application of multi-group cfa in analysing moderation effect of socioeconomic attributes on public housing performance

This study analysed moderation effect of socioeconomic attributes of income and education on public housing performance model using the multi-group confirmatory factor analysis (CFA) method. The objectives of the study was to evaluate the influence of socioeconomic attributes of income and education on public housing performance using occupants’ experience, with a view to proffer recommendations on objective indicator of public housing performance. Literature revealed how little attention is given to effects of socioeconomic attributes on building performance in post occupancy evaluation (POE). This leads to misuse of resources in facilities management. Sample households of 350 were selected in Gombe metropolis, Nigeria, by systematic random sampling to answer questionnaires as the major instrument of data collection. SPSS Version 22 was used for preliminary analyses and AMOS version 21 was used to validate the constructs and develop Structural Equation Model (SEM) of building performance. Results indicated an acceptable SEM model for use in building performance evaluation, with all factor loadings above 0.5 and required fitness indexes achieved. Moderation effect of occupants’ education and income were proved not significant on their experience responses. The finding portrayed occupants’ experience as objective tool for measuring building performance Implication of this finding is in supporting the notion that experience is objective medium of measuring performance than satisfaction. Hence, scholars and professionals in housing should be cautious of the use of these terminologies interchangeably

Interference-aware multipath video streaming in vehicular environments

The multipath transmission is one of the suitable transmission methods for high data rate oriented communication such as video streaming. Each video packets are split into smaller frames for parallel transmission via different paths. One path may interfere with another path due to these parallel transmissions. The multipath oriented interference is due to the route coupling which is one of the major challenges in vehicular traffic environments. The route coupling increases channel contention resulting in video packet collision. In this context, this paper proposes an Interference-aware Multipath Video Streaming (I-MVS) framework focusing on link and node disjoint optimal paths. Specifically, a multipath vehicular network model is derived. The model is utilized to develop interference-aware video streaming method considering angular driving statistics of vehicles. The quality of video streaming links is measured based on packet error rate considering non-circular transmission range oriented shadowing effects. Algorithms are developed as a complete operational I-MVS framework. The comparative performance evaluation attests the benefit of the proposed framework considering various video streaming related metrics