On a number of inflection points of activity curves for a regular solution

Concentration dependencies of components' activities in a binary non-ideal solution have at least one inflection point. It is proved that in the case of the regular solution, there is only one inflection point.     

More than just a plant: cushion plants as biodiversity protectors in high mountains of Siberia

The Siberian cushion plants have been little studied. This research aimed to reveal their morphological and ecological features as enabling them to survive and to protect biodiversity in a changing environment. The research was conducted in the Altai Mountains, Russia, at 1750–4000 m a.s.l. The temperature of cushion plants, the surrounding air and soil were studied. Substrate samples from cushions and topsoil were taken and analysed. Indices of hydrolytic acidity, loss on ignition and percentage of humus, phosphorus and nitrogen were taken into account in soil analysis. Bryophytes and vascular plants inhabiting cushions were studied. Fifty-four cushion plant species were classified into six morphological types based on the cushion skeleton construction and divided into ‘obligate’ and ‘facultative’ cushion plants. The temperature inside the cushions is much more stable, than that of their environment. Accumulation of organic matter within the cushions and in the sphere of their vital functions represents a process of local primary soil formation and makes cushion plant communities indifferent to the ground quality. The functional features of the cushion plants allow them to occupy high-mountain habitats and to be the centres of communities including other plants and animals, which can be found in an extreme environment only within or near the cushions, increasing the biological diversity of the alpine mountain zone.     

Governance in Houston: Growth Theories and Urban Pressures

Abstract: The article explores the political and social forces that have shaped local governance in Houston. This research will present a historical review of the role of local government and then examine two theoretical interpretations, the public choice and political economy perspectives, in explaining Houston's governance and public policy directions. The work will also show that recent events in Houston that might initially appear to contradict the city's historical development practices, such as greater ethnic sensitivity and increasing concern for the environment, have in no way challenged the city's pro‐growth agenda. The new directions in Houston's policy are simply a reflection of a different growth strategy reflecting changing demographics in the city and the new reality of Houston's diversifying economy.     

Efficient recovery of CO2 from flue gas by clathrate hydrate formation in porous silica gels

Thermodynamic measurements and NMR spectroscopic analysis were used to show that it is possible to recover CO2 from flue gas by forming a mixed hydrate that removes CO2 preferentially from CO2/N2 gas mixtures using water dispersed in the pores of silica gel. Kinetic studies with 1H NMR microimaging showed that the dispersed water in the silica gel pore system reacts readily with the gas, thus obviating the need for a stirred reactor and excess water. Hydrate phase equilibria for the ternary CO2-N2-water system in silica gel pores were measured, which show that the three-phase hydrate-water-rich liquid-vapor equilibrium curves were shifted to higher pressures at a specific temperature when the concentration of CO2 in the vapor phase decreased. 13C cross-polarization NMR spectral analysis and direct measurement of the CO2 content in the hydrate phase suggested that the mixed hydrate is structure I at gas compositions of more than 10 mol % CO2, and that the CO2 molecules occupy mainly the more abundant 5(12)6(2) cages. This makes it possible to achieve concentrations of more than 96 mol % CO2 gas in the product after three cycles of hydrate formation and dissociation. 1H NMR microimaging showed that hydrate yields of better than 85%, based on the amount of water, could be obtained in 1 h when a steady state was reached, although approximately 90% of this yield was achieved after approximately 20 min of reaction time.     

Calculation of parameters of internal heat and mass transfer during drying of fiber material

Using arguments and characteristic functions of the thermodynamics of irreversible processes, calculations are made of parameters of internal heat and mass transfer during drying of fiber material in melted paraffin.     

The IoT Architectural Framework,Design Issues and Application Domains

The challenge raised by the introduction of Internet of Things (IoT) concept will permanently shape the networking and communications landscape and will therefore have a significant social impact. The ongoing IoT research activities are directed towards the definition and design of open architectures and standards, but there are still many issues requiring a global consensus before the final deployment. The paper presents and discusses the IoT architectural frameworks proposed under the ongoing standardization efforts, design issues in terms of IoT hardware and software components, as well as the IoT application domain representatives, such as smart cities, healthcare, agriculture, and nano-scale applications (addressed within the concept of Internet of Nano-Things). In order to obtain the performances related to recently proposed protocols for emerging Industrial Internet of Things applications, the preliminary results for Message Queuing Telemetry Transport and Time-Slotted Channel Hopping protocols are provided. The testing was performed on OpenMote hardware platform and two IoT operating systems: Contiki and OpenWSN.     

Understanding bottom-up continuous hydrothermal synthesis of nanoparticles using empirical measurement and computational simulation

Continuous hydrothermal synthesis was highlighted in a recent review as an enabling technology for the production of nanoparticles. In recent years, it has been shown to be a suitable reaction medium for the synthesis of a wide range of nanomaterials. Many single and complex nanomaterials such as metals, metal oxides, doped oxides, carbonates, sulfides, hydroxides, phosphates, and metal organic frameworks can be formed using continuous hydrothermal synthesis techniques. This work presents a methodology to characterize continuous hydrothermal flow systems both experimentally and numerically, and to determine the scalability of a counter current supercritical water reactor for the large scale production (>1,000 T·year^–1) of nanomaterials. Experiments were performed using a purpose-built continuous flow rig, featuring an injection loop on a metal salt feed line, which allowed the injection of a chromophoric tracer. At the system outlet, the tracer was detected using UV/Vis absorption, which could be used to measure the residence time distribution within the reactor volume. Computational fluid dynamics (CFD) calculations were also conducted using a modeled geometry to represent the experimental apparatus. The performance of the CFD model was tested against experimental data, verifying that the CFD model accurately predicted the nucleation and growth of the nanomaterials inside the reactor.

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A numerical study concerning brain stroke detection by microwave imaging systems

In this paper, a numerical study devoted to evaluate the application of a microwave imaging method for brain stroke detection is described. First of all, suitable operating conditions for the imaging system are defined by solving the forward electromagnetic scattering problem with respect to simplified configurations and analyzing the interactions between an illuminating electromagnetic wave at microwave frequencies and the biological tissues inside the head. Then, preliminary inversion results are obtained by applying an imaging procedure based on an iterative Gauss-Newton scheme to a realistic model of the human head. The proposed imaging algorithm is able to deal with the nonlinear and ill-posed problem associated to the integral equations describing the inverse scattering problem. The aim of the inversion procedure is related to the determination of the presence of a hemorrhagic brain stroke by retrieving the distributions of the dielectric parameters of the human tissues inside a slice of the head model.