Numerical simulation of a supercritical CO2 geothermosiphon

The thermo-hydraulic performance of a CO₂ geothermosiphon has been numerically investigated using the commercially available software CFX. A simple Engineered (or Enhanced) Geothermal System, EGS, consisting of an injection and a production well as well as a reservoir is numerically simulated. Both water and carbon dioxide have been examined as the working fluid. While the former fluid has been very popular for its availability, the latter offers advantages such as favorable thermodynamic properties as well as the inherent possibility of geosequestration. However, detailed analysis of such CO₂ geothermosiphon systems is not available in the open literature. Higher heat extraction rate from the reservoir at lower pressure drops for a CO₂ geothermosiphon, compared to water-based systems, can be achieved and general criteria for that are presented.     

Biosynthesis and characterisation of solid lipid nanoparticles and investigation of toxicity against breast cancer cell line

Solid lipid nanoparticles (SLNs) comprise non‐toxic surface‐active lipidic agents combined with appropriate ratios of drugs or essential oils. The goal of this research was to investigate the effects of the SLN synthesised using essential oils of Foeniculum vulgare on the MCF‐7 breast cancer cell line. SLNs were prepared by homogenisation and ultrasound techniques and characterised by dynamic light scattering (DLS), zeta potential assessment, and transmission electron microscopy (TEM). 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay (MTT assay), flow‐cytometry, and Acridine‐Orange assay were employed for assessing the biological activities of the SLNs. The average particle size was 55.43 nm and the net surface charge was −29.54 ± 11.67 mV. TEM showed that the mean particle size was 33.55 nm and the synthesised SLNs had a uniform round morphology. The MTT assay showed that the prepared SLNs had high toxicity against MCF‐7 cells and low toxicity against normal HUVECs cells. Flow‐cytometry revealed a noteworthy rise in the subG1 peak of the cell cycle in the cancer cells treated with SLNs compared to the controls, indicating apoptosis in cancer cells. The results also showed discolouration in SLNs‐treated cells, which further confirmed the induction of apoptosis and the toxicity of the SLNs against MCF‐7 cells.     

Compositional verification of a distributed real-time arbitration protocol

A distributed real-time arbitration protocol is specified and verified using an assertional method. The formalism is based on classical Hoare triples which have been extended to deal with real-time properties. To verify design steps, a compositional proof system has been formulated for these extended triples. The intention of the protocol is to resolve contention between a number of concurrent modules that compete to acquire control of a common bus. Therefore our proof method has been adapted to deal with concurrent processes that communicate by means of a common bus. Compositionality makes it possible to verify the required properties of the protocol using only the specifications of the modules. Next we give a top-down derivation of a program implementing a module according to its real-time specification.     

Algorithm and Architecture of Fully-Parallel Associative Memories Based on Sparse Clustered Networks

Associative memories retrieve stored information given partial or erroneous input patterns. A new family of associative memories based on Sparse Clustered Networks (SCNs) has been recently introduced that can store many more messages than classical Hopfield-Neural Networks (HNNs). In this paper, we propose fully-parallel hardware architectures of such memories for partial or erroneous inputs. The proposed architectures eliminate winner-take-all modules and thus reduce the hardware complexity by consuming 65 % fewer FPGA lookup tables and increase the operating frequency by approximately 1.9 times compared to that of previous work. Furthermore, the scaling behaviour of the implemented architectures for various design choices are investigated. We explore the effect of varying design variables such as the number of clusters, network nodes, and erased symbols on the error performance and the hardware resources.     

Multiple expectations: assessing the assumed roles of theory in relation to urban design

Designers take different approaches when dealing with urban problems. Some find solutions in existing theories, some rely on their creativity, and many take a middle way. The questions here are what they expect from theory and how they follow their expectations. This paper examines the ways in which theory is being applied within the field of urban design following on from recent discussions on this topic. The paper then identifies four models for employing theory within urban design: as servant of innovation, as scientific formulation, as a means to control wicked problems, and finally as the subject for critique. In a comparison, these four models are assessed in relation to their use within both design and research contexts. The final part of this paper examines how urban design professionals employ theory in their work within practice and academia. The paper concludes by examining the advantages and disadvantages of each model, and adds that being confined to one model of employing theory would exacerbate urban problems. Reflecting on the interviews, the paper advocates multiple models be used, specifically chosen according to the problem in hand.     

Correction to: Salient object detection using the phase information and object model

Multimedia Tools and Applications - The article Salient object detection using the phase information and object model, written by Hooman Afsharirad and Seyed Alireza Seyedin, was originally...     

A PSO-ANFIS framework for prediction of density of bitumen diluted with solvents

One of the important properties in petroleum engineering calculations in heavy oil reservoirs is the density of bitumen diluted with solvents. It is required in newly developed solvent based enhanced oil recovery methods. Hence, developing accurate models for prediction of this parameter is essential. To tackle this issue, this study presents an accurate model based on adaptive neuro-fuzzy inference system trained by particle swarm optimization (PSO-ANFIS) for estimation of density of bitumen diluted with solvents and hydrocarbon mixtures using experimental data from literature. The accuracy and reliability of results were evaluated by utilizing various statistical and graphical approaches and comparing the predictions of the developed model with literature models. The analysis showed that the PSO-ANFIS model is capable to predict the experimental data with acceptable error and high accuracy. The predictions of the PSO-ANFIS model were also better than the literature models.     

Integration of CATHENA Thermal-Hydraulic Model with CANDU 6 Analytical Simulator Controller

This paper introduces a powerful design and analysis tool named SIMCAT, that is developed to support applications to license a CANDU nuclear reactor, refurbish projects, and support the existing CANDU stations. It consists of the CATHENA （Canadian Algorithm for Thermo-Hydraulic Network Analysis）, the control logics from C6SIM （CANDU 6 Analytical Simulator）, and a communication protocol, PVM （parallel virtual machine）. This is the first time that CATHENA has been successfully coupled directly with a program written in another language. The independence of CATHENA and the C6SIM controllers allows the development of both CATHENA and C6SIM controller to proceed independently.