Integrated River Basin Management in the Multi-jurisdictional River Basins: The Case of the Mekong River Basin

Achieving integrated river basin management in large multi-jurisdictional river basins is a difficult task. In the Mekong River basin some of the countries have begun to implement a cooperative framework, which indicates a desire to achieve a form of integrated management. Significant progress has been made but results still fall short of the ideal. The primary reasons for this includes the lack of institutional capacity of the multi-jurisdictional cooperative authority and its counterpart organizations in each of the participating countries, together with a lack of political drive to develop integrated management as a priority.     

A hybrid variational‐collocation immersed method for fluid‐structure interaction using unstructured T‐splines

We present a hybrid variational‐collocation, immersed, and fully‐implicit formulation for fluid‐structure interaction (FSI) using unstructured T‐splines. In our immersed methodology, we define an Eulerian mesh on the whole computational domain and a Lagrangian mesh on the solid domain, which moves arbitrarily on top of the Eulerian mesh. Mathematically, the problem reduces to solving three equations, namely, the linear momentum balance, mass conservation, and a condition of kinematic compatibility between the Lagrangian displacement and the Eulerian velocity. We use a weighted residual approach for the linear momentum and mass conservation equations, but we discretize directly the strong form of the kinematic relation, deriving a hybrid variational‐collocation method. We use T‐splines for both the spatial discretization and the information transfer between the Eulerian mesh and the Lagrangian mesh. T‐splines offer us two main advantages against non‐uniform rational B‐splines: they can be locally refined and they are unstructured. The generalized‐α method is used for the time discretization. We validate our formulation with a common FSI benchmark problem achieving excellent agreement with the theoretical solution. An example involving a partially immersed solid is also solved. The numerical examples show how the use of T‐junctions and extraordinary nodes results in an accurate, efficient, and flexible method. Copyright © 2015 John Wiley & Sons, Ltd.     

Second harmonic generation diagnostic of layer-by-layer deposition from Disperse Red 1 – functionalized maleic anhydride copolymer

Layer-by-layer (LBL) electrostatic assembly of polyelectrolytes is proving to be an increasingly rich and versatile technique for the formation of multilayered thin films with a wide range of electrical, magnetic, and optical properties. In the present work we synthesized a new non-linear optical (NLO) maleic acid copolymer containing Disperse Red 1 moieties, built-up multilayer assemblies by alternate adsorption of poly(allylamine hydrochloride) (PAH) and maleic copolymer derivative, and carried out an investigation on their second harmonic generation (SHG) properties. The resulting multilayer assemblies exhibit SHG which arises from the non-centrosymmetric alignment of the chromophores in the copolymer. The SHG signal increases with the number of chromophore-containing polymer layers, up to five layers. Further assembly reduces the signal.     

A predictive mechanism for dynamic strain ageing in aluminium-magnesium alloys

Dynamic strain ageing (DSA) is the phenomenon in which solute atoms diffuse around dislocations and retard dislocation motion, leading to negative strain-rate sensitivity (nSRS) and thus to material instabilities during processing, an important issue in commercial metal alloys. Here, we show the mechanism of DSA and nSRS on experimental strain-rate, temperature and stress scales for Al-Mg to be single-atomic-hop motion of solutes from the compression to the tension side of a dislocation core. We derive an analytic expression for the strengthening versus strain rate and temperature that justifies widely used phenomenological forms, provides specific dependences of the parameters on material properties and is supported by atomistic kinetic Monte Carlo simulations. Using literature material properties, the predicted strengthening quantitatively agrees with the experimentally derived behaviour of Al-2.5% Mg at 300 K, and qualitatively agrees with the strain rate and temperature ranges of DSA and nSRS in Al-Mg alloys. The analyses herein show a clear path for multiscale design, from quantum to continuum mechanics, of solute strengthening in face-centred-cubic metal alloys.     

Thermoelastic stresses in a bonded layer due to repetitively pulsed laser radiation

Summary A method is presented for the calculation of thermoelastic stress and displacement fields in a bonded layer that absorbs thermal energy from a repetitively pulsed laser in its surface plane. A function with three adjustable parameters is used to simulate the temporal variation of each pulse while the radial intensity distribution (or mode structure) of each pulse follows a Gaussian profile. The pulse duration is of the order of the characteristic time for heat to diffuse across the layer thickness, and hence axial heat conduction cannot be neglected. Stress and displacement components due to heat absorption from three successive pulses are calculated and examined specifically at the free surface, at selected points within the layer, and at the bonded interface. The stress components at the bonded interface are also examined over a range of layer thicknesses to illustrate key differences between the thermoelastic responses of thin and thick layers.List of symbols a, b, c temporal shape parameters - g(r, z, t/r, 0, 0) function defined by Eq. (6) - g₁(z, p/) function defined by Eq. (27) - g₂(z, p/) function defined by Eq. (29) - j summation index - k _c parameter related to characteristic beam radius - m parameter defined by Eq. (22) - n summation index - p Laplace transform variable - r radial spatial variable - t time - t _r pulse rise time - t _w pulse width - t ^p(j) time at which pulsej achieves peak power - u _r radial displacement - u _z normal displacement - z normal position variable - A, B, C, D functions defined by Eq. (43) - F ₁ function defined by Eq. (39) - F ₂ function defined by Eq. (40) - F ₃ function defined by Eq. (48) - F ₄ function defined by Eq. (53) - G(t–/) function defined by Eq. (33) - (z, t–/) function defined by Eq. (32) - H _i() functions defined by Eqs. (74)-(81) - H(t) unit step function - K thermal conductivity - L layer thickness - N number of pulses in pulse train - P _a average power - P _p peak power - Q _o maximum incident flux for Gaussian source - Q(r) radial intensity distribution - T(r, z, t) auxiliary temperature field - (t) temporal profile of a single pulse - Y(t) temporal profile of pulse train Greek symbols thermal diffusivity - integration variable - o(t) Dirac delta function - duty cycle or ratio of temporal pulse width to pulse train period - ₁ parameter defined by Eq. (39) - ₂ parameter defined by Eq. (40) - coefficient of thermal expansion - shear modulus - v Poisson's ratio - _ij (r, z, t) thermoelastic stress field - temporal integration variable - (r, z, t) thermoelastic displacement potential - pulse train period - (r, z, t) temperature field due to repetitive pulsing - (r, z, t) Love function - (t) function defined by Eq. (15) - ₁ functions defined by Eqs. (64)-(69) Dimensionless quantities are indicated with an asterisk (r ^*, ^*, etc.). An overbar indicates a Laplace transform.Dedicated to Prof. Dr. Dr. h. c. Franz Ziegler on the occasion of his 60th birthday     

A Modular Analog NLMS Structure for Adaptive Filtering

This paper proposes a modular Analog Adaptive filter (AAF) algorithm, in which the coefficient adaptation is carried out by using a time varying step size analog normalized LMS (NLMS) algorithm, which is implemented as an external analog structure. The proposed time varying step size is estimated by using the first element of the crosscorrelation vector between the output error and reference signal, and the first element of the crosscorrelation vector between the output error and the adaptive filter output signal, respectively. Proposed algorithm reduces distortion when additive noise power increases or DC offsets are present, without significatively decreasing the convergence rate nor increasing the complexity of the conventional NLMS algorithms. Simulation results show that proposed algorithm improves the performance of AAF when DC offsets are present. The proposed VLSI structure for the time varying step size normalized NLMS algorithm has, potentially, a very small size and faster convergence rates than its digital counterparts. It is suitable for general purpose applications or oriented filtering solution such as echo cancellation and equalization in cellular telephony in which high performance, low power consumption, fast convergence rates and small size adaptive digital filters (ADF) are required. The convergence performance of analog adaptive filters using integrators like first order low pass filter is analyzed.     

Surface chemistry of carbon nanotubes impacts the growth and expression of water channel protein in tomato plants

Specific properties of carbon nanotubes, such as their level of agglomeration in the medium and their surface characteristics, can be critical for the physiological response of plants upon application of carbon nanotubes. The correlations among the level of aggregation, the type of functional group on the surface of the carbon nanotubes, and the growth performance of tomato plants are documented.     

Renal‐Clearable PEGylated Porphyrin Nanoparticles for Image‐Guided Photodynamic Cancer Therapy

Nanomaterials with renal clearance from the body within a reasonable timescale have shown great promises in the area of nanomedicine recently. However, the integration of theranostic and renal clearance properties into a single ultrasmall nanostructure remains a great challenge. Herein, meso‐tetra(4‐carboxyphenyl)porphyrin (TCPP) structure is utilized as a model, for the first time using noninvasive dynamic positron emission tomography (PET) imaging to investigate the balance of the renal clearance and tumor uptake behaviors of polyethylene glycol (PEG)‐modified porphyrin nanoparticles (TCPP‐PEG) with various molecular weights. This study finds that TCPP‐PEG nanoparticles with larger molecular weight show higher tumor uptake due to the enhanced permeability and retention effect, while the lower ones tend to be better for renal clearance. Based on dynamic PET and fluorescence dual‐modal imaging modalities, the TCPP‐PEG_10K nanoparticles seem to be an excellent choice for the balance of renal clearance and tumor retention. In vitro and in vivo photodynamic therapy confirms an excellent therapeutic efficacy. Therefore, this work presents a simplified approach to fabricate and select biocompatible multifunctional TCPP‐PEG‐based theranostic agents with renal clearance behavior, which highlights the clinical application potential of TCPP‐PEG nanoparticles as theranostic probes for imaging‐guided cancer therapy.     

Cloud Networking Computing

Wireless Personal Communications -     

Using multi-threshold threshold gates in RTD-based logic design: A case study

The basic building blocks for resonant tunneling diode (RTD) logic circuits are threshold gates (TGs) instead of the conventional Boolean gates (AND, OR, NAND, NOR) due to the fact that, when designing with RTDs, TGs can be implemented as efficiently as conventional ones, but realize more complex functions. Recently, RTD structures implementing multi-threshold threshold gates (MTTGs) have been proposed which further increase the functionality of the original TGs while maintaining their operating principle and allowing also the implementation of nanopipelining at the gate level. This paper describes the design of n-bit adders using these MTTGs. A comparison with a design based on TGs is carried out showing advantages in terms of power consumption and power delay product.