Differentiation of interlayer and adsorbed water in hydrated portland cement by thermal analysis

Work leading to the new model of hydrated portland cement has shown that much of the water previously considered to reside on free surfaces exists as interlayer water. In the present work samples were conditioned at various relative humidities for times varying from to 14 months and were dried to two different levels before conditioning, one being d-dry. Conditions were chosen, based on the model, so that the different states of water could be clearly illustrated. It was concluded that thermal analysis allows differentiation of interlayer and physically adsorbed water and that the different degrees of drying and very long times allowed for equilibration support all sorption results on which the new model of hydrated portland cement was based.     

Enriched energy storage capability and bi-functional ability of boron-doped graphene as efficient electrode for supercapacitors and lithium sulfur batteries

This work depicts the preparation of boron-doped graphene (BG) and its application as bi-functional electrode material for both the supercapacitors and lithium–sulfur (Li–S) battery. Structural, morphological, and elemental analyses of the prepared material were acquired via X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, Scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. BG worked well in supercapacitors as a capacitive electrode, featuring a high specific capacitance of 239 F g^?1 at a current rate of 1 A g^?1 and high capacity retention of 85% over 10,000 charge/discharge cycles with average coulombic efficiency of 99.5%. In addition, the sulfur/boron-doped graphene (SBG) binary composite was prepared via melt diffusion method and used as the positive electrode material in Li–S batteries. BG is effective polysulfide adsorbent and its sheet-like structure accommodates more content of sulfur, which restricts the shuttle effect and volume changes of active material during cycling. The SBG composite shows an initial discharge capacity of 1355 mAh g^?1, and it retains the discharge capacity of 636 mAh g^?1 over the 50 cycles. The present work demonstrates that BG is an efficient electrode material for energy storage applications.

     

Determining the spatial variation of phosphorus in a lake system using remote sensing techniques

Lakes are versatile ecosystems, with eutrophication being a serious problem affecting their condition and trophic status. Eutrophication can lead to an over‐abundance of macrophytes in lakes, producing favourable conditions for mosquito larvae. Increased eutrophication is attributed in most to excessive phosphorus concentrations in lake water. Satellite imagery analysis now plays a prominent role for quickly assessing water quality over a large area. The present study is an attempt to illustrate the variation of phosphate and total phosphorus concentrations in Akkulam–Veli Lake, Kerala, India, using Indian Remote Sensing satellite (IRS P6‐ LISS III) imagery. A multiple regression equation derived using radiance in the red and MIR bands in the imagery was found to yield superior results for predicting the phosphate concentration, whereas a simple regression equation using radiance in red band was found to yield good results for the total phosphorus concentration in lake water. Accordingly, the trophic status of the lake system can be determined easily from satellite imagery in this manner.     

Alteration of structure and mobility of erythrocyte aggregates under normal- to microgravity conditions

An experimental analysis of the aggregates structure and their mobility under normal- and micro-g conditions is carried out. Fresh well mixed erythrocyte suspensions in plasma at 8.0% hematocrit are placed in a glass chamber and on-line video microscopic recording of the aggregation process under microgravity condition is carried out. The analysis of aggregate structure and mobility are carried out by an IBM-PC/AT based image processing system. The results show that (a) under normal gravity conditions the velocity of the formed aggregates depend on their sizes which tend to grow further by interacting with single cells and small aggregates, (b) under microgravity conditions the mobility of the aggregates reduces to zero and an alteration in their structural parameters is observed.     

Tracking humoral responses using self assembling protein microarrays

The humoral immune response is a highly specific and adaptive sensor for changes in the body's protein milieu, which responds to novel structures of both foreign and self antigens. Although Igs represent a major component of human serum and are vital to survival, little is known about the response specificity and determinants that govern the human immunome. Historically, antigen-specific humoral immunity has been investigated using individually produced and purified target proteins, a labor-intensive process that has limited the number of antigens that have been studied. Here, we present the development of methods for applying self-assembling protein microarrays and a related method for producing 96-well formatted macroarrays for monitoring the humoral response at the proteome scale. Using plasmids encoding full-length cDNAs for over 850 human proteins and 1700 pathogen proteins, we demonstrate that these microarrays are highly sensitive, specific, reproducible, and can simultaneously measure immunity to thousands of proteins without a priori protein purification. Using this approach, we demonstrate the detection of humoral immunity to known and novel self-antigens, cancer antigens, autoimmune antigens, as well as pathogen-derived antigens. This represents a powerful and versatile tool for monitoring the immunome in health and disease.     

Lasing in active, sub-mean-free path-sized systems with dense, random, weak scatterers

We report enhanced emission and gain narrowing in Rhodamine 590 perchlorate dye in an aqueous suspension of polystyrene microspheres. A systematic experimental study of the threshold condition for and the gain narrowing of the stimulated emission over a wide range of dye concentrations and scatterer number densities showed several interesting features, even though the transport mean free path far exceeded the system size. The conventional diffusive-reactive approximation to radiative transfer in an inhomogeneously illuminated random amplifying medium, which is valid for a transport mean-free path much smaller than the system size, is clearly inapplicable here. We propose a new probabilistic approach for the present case of dense, random, weak scatterers involving the otherwise rare and ignorable sub-mean-free-path scatterings, now made effective by the high gain in the medium, which is consistent with experimentally observed features.     

Classification of mental tasks using stockwell transform

In recent years, various physiological signal based rehabilitation systems have been developed for the physically disabled in which electroencephalographic (EEG) signal is one among them. The efficiency of such a system depends upon the signal processing and classification algorithms. In order to develop an EEG based rehabilitation or assistive system, it is necessary to develop an effective EEG signal processing algorithm. This paper proposes Stockwell transform (ST) based analysis of EEG dynamics during different mental tasks. EEG signals from Keirn and Aunon database were used in this study. Three classifiers were employed such as k-means nearest neighborhood (kNN), linear discriminant analysis (LDA) and support vector machine (SVM) to test the strength of the proposed features. Ten-fold cross validation method was used to demonstrate the consistency of the classification results. Using the proposed method, an average accuracy ranging between 84.72% and 98.95% was achieved for multi-class problems (five mental tasks).     

Laminar radial flow electrochemical reactors. I. Flow fields

The velocity fields of three laminar radial flow electrochemical reactors are modeled using numerical and semi-analytical techniques. The capillary gap cell configuration is modeled using Galerkin finite element (GFEM) analysis and the asymptotic form of its velocities presented. An approximate asymptotic expression for entry length is also derived and compared to predicted entry lengths from the GFEM. Qualitative agreement is achieved. Two areas of flow separation are observed, their location being a function of gap width, flow Reynolds number (Re) and inlet pipe diameter. The rotating electrolyzer (REL) flow field is also simulated with the GFEM model. The insensitivity of the REL radial velocity profiles as a function of flow rate is shown. The shape of the radial velocity profiles and the degree of separation of the radial velocity jets are shown to be determined by the Taylor number (being the ratio of half-gap width over the theoretical boundary layer thickness). The asymptotic entry length solution is shown to provide a better estimate for this cell than for the capillary gap cell. Unlike the previous cells the pump cell shows less asymptotic behavior and is therefore more difficult to simulate. The GFEM approach is usually too costly for this cell and therefore perturbation techniques are applied. The resulting semi-analytical solution adequately represents laminar pump cell velocity profiles over a broad range of parameter values and is very short and easy to implement. One high Taylor number simulation is performed using the GFEM and the previously reported decoupling of electrodic mass transfer is interpreted via velocity profiles.Nomenclature a gap width - Q volumetric flow rate (m³ s^–1) - r dimensionless radius - R radius (m) - Re Reynolds number (v _c a/v) - Re _gap gap Reynolds number (a ²/v) - Re rotational Reynolds number (R ₀ ² /v) - Sc Schmidt number (v/D) - spin dimensionless group (Equation 8) - t time (s) - v _c characteristic velocity (m s^–1) two defined: for FEM analysis it wasQ/b ² for Perturbation analysis 6Q/(2R _in a) - v _r dimensionless radial velocity - v _z dimensionless axial velocity - v dimensionless azimuthal velocity - V velocity (m s^–1) - z dimensionless axial distance Greek symbols Taylor number (Equation 7) - ratio of characteristic lengths (a/R _o ) - viscosity (kg m^–1 s) - constant - density (kg m^–3) - azimuthal direction - kinematic viscosity (m² s^–1) - angular velocity (rad s^–1)