Adsorptive separation of arsenate and arsenite anions from aqueous medium by using orange waste

Cellulose and orange waste were chemically modified by means of phosphorylation. The chemically modified gels were further loaded with iron(III) in order to create a suitable chelating environment for arsenate and arsenite removal. The loading capacity for iron(III) on the gel prepared from orange waste (POW) was 1.21 mmol g⁻¹ compared with 0.96 mmol g⁻¹ for the gel prepared from cellulose (PC). Removal tests of arsenic with the iron(III)-loaded gel were carried out batchwise and by using a column. Arsenite removal was favored under alkaline condition for both PC and POW gels, however, the POW gel showed some removal capability even at neutral pH. On contrary, arsenate removal took place under acidic conditions at pH=2–3 and 2–6 for the PC and POW gels, respectively. Since iron(III) loading is higher on the POW gel than on the PC gel greater arsenic removal has been achieved by the POW gel compared with the PC gel. It can be concluded that the POW gel can be used for the removal and recovery of both arsenite and arsenate from arsenic contaminated wastewater.     

Simultaneous measurements of thermal conductivity and thermal diffusivity of Se90?xTe5Sn5Inx (x?=?0, 3, 6, and 9) multi-component chalcogenide glasses

Measurements of thermal conductivity and thermal diffusivity of twin pellets of Se_90−x Te₅Sn₅In _x (x = 0, 3, 6, and 9) chalcogenide glasses were carried out at room temperature using transient plane source technique. The measured values of thermal conductivity and thermal diffusivity were used to determine the specific heat per unit volume of these glasses in the composition range of investigation. Results indicated that both values of thermal conductivity and thermal diffusivity were increased with addition of indium concentration at the cost of selenium, whereas the specific heat per unit volume was slightly decreases with increase of indium content. This compositional dependence behavior of the thermal conductivity and diffusivity can be explained in terms of the iono-covalent type of bonds, which In (indium) makes with Se as it is incorporated in the Se–Te–Sn glass.     

Comprehensive models for predicting aromaticity of coals

The principal objective of the present study is to develop suitable models to predict aromaticity of coals on the basis of atomic ratios of the H/C, O/C, O/H, and weight percentage volatile matter (V.M.) in coals. Based on dry mineral matter free (dmmf) basis, aromaticity (fa) of coal is computed through the following expressions: eqalignno{{rm fa}_1&= 1.202913 - 0.0126^{ast} {rm V.M}.,&(2)cr{rm fa}_2&= 1.36396 - 0.53715^{ast} {rm O}/{rm C} - 0.7846^{ast} {rm H}/{rm C},&(3)cr{rm fa}_3&= 1.365615 - 0.51187^{ast} {rm O}/{rm C} - 0.02108^{ast} {rm O}/{rm H} - 0.78645^{ast} {rm H}/{rm C},&(4)cr{rm fa}_4&= 174.4405 + 621.6823^{ast} {rm O}/{rm C} - 856.495^{ast} {rm O}/{rm H} - 629.617^{ast} {rm H}/{rm C}&(5) cr& quad+ 9.133897^{ast} {rm V.M}.} The absolute average % error of estimate and correlation coefficients of the developed models (Equations (2), (3), (4), and (5)) were found to be 7.48,0.91; 6.23, 0.92; 6.24, 0.92; and 6.23, 0.92 on (dmmf) basis, respectively.     

Evaluation of coherence interference in optical wireless communication through multiscattering channels

Optical wireless communication has been the subject of much research in recent years because of the increasing interest in laser satellite-ground links and urban optical wireless communication. The major sources of performance degradation have been identified as the spatial, angular, and temporal spread of the propagating beam when the propagation channel is multiscattering, resulting in reduced power reception and intersignal interference, as well as turbulence-induced scintillations and noise due to receiver circuitry and background illumination. However, coherence effects due to multipath interference caused by a scattering propagation channel do not appear to have been treated in detail in the scientific literature. We attempt a theoretical analysis of coherence interference in optical wireless communication through scattering channels and try to quantify the resultant performance degradation for different media. We conclude that coherence interference is discernible in optical wireless communication through scattering channels and is highly dependent on the microscopic nature of the propagation medium.     

Securing a compiler transformation

A compiler optimization may be correct and yet be insecure. This work focuses on the common optimization that removes dead (i.e., useless) store instructions from a program. This operation may introduce new information leaks, weakening security while preserving functional equivalence. This work presents a polynomial-time algorithm for securely removing dead stores. The algorithm is necessarily approximate, as it is shown that determining whether new leaks have been introduced by dead store removal is undecidable in general. The algorithm uses taint and control-flow information to determine whether a dead store may be removed without introducing a new information leak. A notion of secure refinement is used to establish the security preservation properties of other compiler transformations. The important static single assignment optimization is, however, shown to be inherently insecure.     

The Jamiołkowski Isomorphism and a Simplified Proof for the Correspondence Between Vectors Having Schmidt Number <Emphasis Type="Italic">k</Emphasis> and <Emphasis Type="Italic">k</Emphasis>-Positive Maps

Positive maps which are not completely positive are used in quantum information theory as witnesses for convex sets of states, in particular as entanglement witnesses and, more generally, as witnesses for states having Schmidt number not greater than k. Such maps and witnesses are related to k-positive maps, and their properties may be investigated by making use of the Jamiołkowski isomorphism. In this article we review the properties of this isomorphism, noting that there are actually two related mappings bearing that name. As a new result, we give a simplified proof for the correspondence between vectors having Schmidt number k and k-positive maps and thus for the Jamiołkowski criterion for complete positivity. Another consequence is a special case of a result by Choi, namely that k-positivity implies complete positivity, if k is the dimension of the smaller one of the Hilbert spaces on which the operators act.     

Modelling of GaAs-MMIC microstrip line up to 40 GHz

Modelling of MMIC multidielectric microstrip line on GaAs substrate for its precise characterization has been presented in this article. An accurate design database for the characteristic parameters of the microstrip line, namely, effective dielectric constant, characteristic impedance, and attenuation coefficient, has been generated using the spectral-domain method (SDM). The accuracy of the developed database for the frequency range 1 to 40 GHz has been verified with the experimental results. On-wafer measurements have been carried out to minimize the parasitic losses at the high frequencies and the effect of CPW-pads has been de-embedded from the measured S-parameters to obtained accurate characteristic parameters of the microstrip line. The theoretical and the measured values of the characteristic parameters of microstrip lines show good agreement within 1% to 2%. This work is expected to be useful in GaAs foundries for accurate MMIC-CAD modelling of microstrip lines up to 40 GHz. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 475–482, 2004.     

Local proofs for global safety properties

This paper explores locality in proofs of global safety properties of concurrent programs. Model checking on the full state space is often infeasible due to state explosion. A local proof, in contrast, is a collection of per-process invariants, which together imply the desired global safety property. Local proofs can be more compact than global proofs, but local reasoning is also inherently incomplete. In this paper, we present an algorithm for safety verification that combines local reasoning with gradual refinement. The algorithm gradually exposes facts about the internal state of components, until either a local proof or a real error is discovered. The refinement mechanism ensures completeness. Experiments show that local reasoning can have significantly better performance over the traditional reachability computation. Moreover, for some parameterized protocols, a local proof can be used as the basis of a correctness proof over all instances.     

IVIM–DKI for differentiation between prostate cancer and benign prostatic hyperplasia: comparison of 1.5 T vs. 3 T MRI

Magnetic Resonance Materials in Physics, Biology and Medicine - To implement an advanced spatial penalty-based reconstruction to constrain the intravoxel incoherent motion (IVIM)–diffusion...     

Infrared holography using a microbolometer array

We describe a series of experiments to demonstrate holography at far-infrared wavelengths using an uncooled microbolometer array. Simple interference patterns and Fresnel zone holograms are recorded with a 10 W cw CO(2) laser illumination in a Mach-Zehnder interferometer setup. A sparse-sampling method is used to sample the hologram at a rate dependent on the bandwidth of the object wavefront rather than the carrier frequency. The samples are then used to reconstruct the complex object wavefront in the hologram plane, which is Fresnel backpropagated for image reconstruction. Uncooled microbolometer arrays are most commonly used in passive mode to image the thermal-blackbody radiation. Their technology has matured to include the wavelength range of far-infrared to submillimeter radiation. The use of microbolometers with active illumination for holography, as described in this paper, suggests their interesting future applications.