A framework for state-space estimation with uncertain models

Develops a framework for state-space estimation when the parameters of the underlying linear model are subject to uncertainties. Compared with existing robust filters, the proposed filters perform regularization rather than deregularization. It is shown that, under certain stabilizability and detectability conditions, the steady-state filters are stable and that, for quadratically-stable models, the filters guarantee a bounded error variance. Moreover, the resulting filter structures are similar to various (time- and measurement-update, prediction, and information) forms of the Kalman filter, albeit ones that operate on corrected parameters rather than on the given nominal parameters. Simulation results and comparisons with ℋ_∞ guaranteed-cost, and set-valued state estimation filters are provided     

Effects of DUT mismatch on the noise figure characterization: a comparative analysis of two Y-factor techniques

Device mismatch seriously degrades accuracy in noise figure characterization. The suitability of corrections to the gain definitions for a more precise noise figure evaluation for mismatched devices is investigated and compared to classical techniques. The effects of device mismatch on the noise figure of the noise-meter receiver and its impact on the final accuracy are analyzed.     

Comparison studies between cement and cement-kaolinite properties for incorporation of low-level radioactive wastes

Comparison between the properties of cement and cement mixed with 7.5% kaolinite was performed to choose the most suitable matrix to incorporate radio-active wastes. The cement-kaolinite mixtures were prepared as uncured, cured, and heated specimens. The physical properties of the cement-kaolinite mixture, namely density, porosity, and water absorption percent, were determined. Compressive strength, infrared spectra, thermal analysis, and the effect of gamma rays on the samples were studied. The studies were extended to the cement-kaolinite mixture in the presence of some chemical additives at different concentrations. Leachability of radioactive isotopes from the cement-kaolinite mixture was measured as a function of time. The physical and mechanical properties of cement were decreased in the presence of 7.5% kaolinite, whereas ¹³⁷Cs and ⁶⁰Co were less leached from the cement-kaolinite mixture.     

Investment Risk Analysis in Airport Parking Facility Development

Although parking revenue is a principal source of income, supply of parking infrastructure at airports is based largely on expected needs. Although that is a rational basis, high investment costs and management fees are requiring developers and financiers to carefully analyze investment risks. This paper focuses on sources of investment risk in airport parking infrastructure development and discusses the application of Monte Carlo simulation to estimate and understand the impacts of cash flow uncertainties on project feasibility. It is shown that cost overruns, which are common in construction project development, have the most significant impact on return risk.     

Progression from Graphene and Graphene Oxide to High Performance Polymer-Based Nanocomposite: A Review

In this article, various types of carbon nanofiller and modification of graphene oxide and graphene for the preparation of polymer-based nanocomposites are reviewed. Recently, polymer/graphene and graphene oxide-based materials have attracted tremendous interest due to high performance even at low filler content. The property enhancement is due to the high aspect ratio, high surface area and excellent electrical, thermal and mechanical properties of nanofiller. Different techniques have been employed to fabricate polymer/graphene and graphene oxide nanocomposite with uniform dispersion due to fine matrix/nanofiller interaction. Here we discuss the structure, properties and preparation of these nanocomposites.     

An Environmentally Benign,Highly Efficient Catalytic Reduction of p‐Nitrophenol using a Nano‐Sized Nickel Catalyst Supported on Silica‐Alumina

A green and effective method is reported for the reduction of p‐nitrophenol to p‐aminophenol using a nano‐sized nickel catalyst supported on silica‐alumina in the presence of hydrazine hydrate as an alternative source of hydrogen. It was found that nickel loaded on a silica‐alumina support is a very effective catalyst in the hydrogenation of p‐nitrophenol to p‐aminophenol. Thus it attained 100% conversion in only 69 seconds instead of 260 seconds for commercial Raney nickel. In addition, the possibility to reuse it more than one time with great efficiency gives it another advantage over commercial Rainey nickel which cannot be used more than once. This economical and environmentally friendly method provides a potentially new approach for the synthesis of the intermediate product of paracetamol in industry, which overcomes the drawbacks of the known reduction methods. The prepared catalysts were fully characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), and electron spin resonance (ESR) tehniques.     

Semisynthetic Latrunculin Derivatives as Inhibitors of Metastatic Breast Cancer: Biological Evaluations,Preliminary Structure–Activity Relationship and Molecular Modeling Studies

The microfilament cytoskeleton protein actin plays an important role in cell biology and affects cytokinesis, morphogenesis, and cell migration. These functions usually fail and become abnormal in cancer cells. The marine‐derived macrolides latrunculins A and B, from the Red Sea sponge Negombata magnifica, are known to reversibly bind actin monomers, forming 1:1 stoichiometric complexes with G‐actin, disrupting its polymerization. To identify novel therapeutic agents for effective treatment of metastatic breast cancer, several semisynthetic derivatives of latrunculin A with diverse steric, electrostatic, and hydrogen bond donor and acceptor properties were rationally prepared. Analogues were designed to modulate the binding affinity toward G‐actin. Examples of these reactions are esterification, acetylation, and N‐alkylation. Semisynthetic latrunculins were then tested for their ability to inhibit pyrene‐conjugated actin polymerization, and subsequently assayed for their antiproliferative and anti‐invasive properties against MCF7 and MDA‐MB‐231 cells using MTT and invasion assays, respectively.     

Removal of toxic aqueous ions using amorphous AlPO4

Aluminium phosphate (AlPO₄) was characterized using X-ray diffractometry (XRD), Fourier Transform infrared (FTIR), point of zero charge (PZC) and dissolution studies. XRD showed the sample to be amorphous, FTIR confirmed the presence of OH groups on the surface and PZC was determined at pH 3.45. The dissolution study illustrated a decrease in dissolution with an increase in the pH. Potentiometric titration data were fit to the Gaines–Thomas equation, which showed that AlPO₄ is a weakly acidic ion exchanger. Sorption studies were carried out at pH 4–6 and temperatures 293–323 K. The uptake of metal ions was observed to increase with an increase in the pH and temperature. The surface selectivity towards metal ions was found in the order Pb²⁺> Cu²⁺> Cd²⁺. Sorption data were fit to the new equation derived from the proposed mechanism for metal ion uptake. Various parameters such as stoichiometry of the surface H⁺ ion release, equilibrium constant, standard enthalpy, entropy and free energy changes were evaluated from the plots. The values of all these parameters were found to be closely related to the values reported in the literature.