Removal of mercury (II) from aqueous solution by using rice residues

Sorption potential of rice residues for Hg(II) removal from aqueous solution was investigated. Rice husk (RH) and rice straw (RS) were selected and treated with sodium hydroxide (NaOH). The raw and modified adsorbents were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and BET surface area measurements. The effects of pH, initial ion concentration, and agitation time on the removal process were studied in batch adsorption experiments. Two simple kinetic models, which are pseudo-first-order and pseudo-second-order, were tested to investigate the adsorption mechanisms. The kinetic data fits to pseudo second order model with correlation coefficients greater than 0.99 for all adsorbents. The equilibrium data fitted well with the Langmuir compared to Freundlich isotherm models. Alkali-treated adsorbent obtained larger surface area and RH-NaOH showed highest adsorption capacity followed by RS-Pure > RH-Pure > RS-NaOH. The maximum removal efficiency obtained by RH-NaOH and RS-Pure was 42 mg/l (80%) at pH 6.5 and with 2 days contact time (for 50 mg/l initial concentration and 25 mg adsorbents)

Nonlinear robust controller design for multi-robot systems with unknown payloads

This work is concerned with the control problem of a multi-robot system handling a payload with unknown mass properties. Force constraints at the grasp points are considered. Robust control schemes are proposed that cope with the model uncertainty and achieve asymptotic path tracking. To deal with the force constraints, a strategy for optimally sharing the task is suggested. This strategy basically consists of two steps. The first detects the robots that need help and the second arranges that help. It is shown that the overall system is not only robust to uncertain payload parameters, but also satisfies the force constraints

Energy and momentum deposited into a QCD medium by a jet shower

Hard partons moving through a dense QCD medium lose energy by radiative emissions and elastic scatterings. Deposition of the radiative contribution into the medium requires rescattering of the radiated gluons. We compute the total energy loss and its deposition into the medium self-consistently within the same formalism, assuming perturbative interaction between probe and medium. The same transport coefficients that control energy loss of the hard parton determine how the energy is deposited into the medium; this allows a parameter free calculation of the latter once the former have been computed or extracted from experimental energy loss data. We compute them for a perturbative medium in hard thermal loop (HTL) approximation. Assuming that the deposited energy-momentum is equilibrated after a short relaxation time, we compute the medium's hydrodynamical response and obtain a conical pattern that is strongly enhanced by showering.Comment: 4 pages, 3 figures, revtex4, intro modified, typos correcte

Radiotherapy: Impact of quality of life and need for psychological care: Results of a longitudinal study

Background: In the framework of a prospective longitudinal study, the quality of life (QoL) and support requirements of patients from a university hospital department of radiotherapy were evaluated for the first time by means of established psychodiagnostic questionnaires. Patients and Methods: At first, 732 patients were screened, of whom 446 (60.9%) fulfilled the criteria for inclusion; 39.1% did not (refusals 21.0%, low Karnofsky performance status 6.6%, management problems 3.4%, language barriers 3.0%, cognitive restrictions 2.6%, death 2.5%). Disease-specific aspects of QoL (Functional Assessment of Cancer Treatment - General, FACT-G) and moderating variables {[}Social Support Scale (SSS), Disease Coping (FKV), Self-Assessment Depression Scale (SDS), and Self-Defined Care Requirements (BB)] were self-rated by patients with different tumor types before radiotherapy (T1), after radiotherapy (T2), and 6 weeks after the end of radiotherapy (T3). We studied 265 patients (157 male, 108 female; median age 58.6 years) with complete data of three time points. Results: In general, QoL of patients decreased significantly over all time points in all subscales. Social support was rated high and remained constant throughout the treatment. Apparent coping mechanisms were active problem-oriented coping, leisure activities, and self-support. The patients' depression proved to be an important and constant factor without significant changes. The support requirement is characterized by the need for more medical information and dialogue with a physician. Conclusions: Early specific support from personnel with radiotherapeutic skills, during the disease-coping process as well as during rehabilitation, should be a permanent component of an integrated radiooncological treatment schedule

Bose-Einstein condensation in linear sigma model at Hartree and large N approximation

The BEC of charged pions is investigated in the framework of O(4) linear sigma model. By using Cornwall-Jackiw-Tomboulis formalism, we have derived the gap equations for the effective masses of the mesons at finite temperature and finite isospin density. The BEC is discussed in chiral limit and non-chiral limit at Hartree approximation and also at large N approximation.Comment: 11 pages, 9 figure

Air Passenger Duty and Outbound Tourism Demand from the United Kingdom

On November 1, 1994 an Air Passenger Duty (APD) was introduced in the United Kingdom, and since, this tax continues to be controversial. This article examines the effect of the ADP on UK outbound tourism demand for 10 international destinations. An autoregressive distributed lag model is developed and income, price, and tax elasticities are estimated. The income and price elasticities obtained, ranged between 0.36 and 4.11 and −0.05 and −2.02, respectively. The estimated tax elasticities suggest that the implementation of APD had a negative effect on UK outbound travel for five destinations and the demand is inelastic to changes in taxes although the magnitudes vary across destinations. The general message is that although the stated objective of APD is to reduce travel and associated carbon emissions, the effectiveness of APD, however, has been marginal; travelers are prepared to pay more in the main to maintain their demand

Entanglement creation and distribution on a graph of exchange-coupled qutrits

We propose a protocol that allows both the creation and distribution of entanglement, resulting in two distant parties (Alice and Bob) conclusively sharing a bipartite Bell State. The system considered is a graph of three-level objects ("qutrits") coupled by SU(3) exchange operators. The protocol begins with a third party (Charlie) encoding two lattice sites in unentangled states, and allowing unitary evolution under time. Alice and Bob perform a projective measurement on their respective qutrits at a given time, and obtain a maximally-entangled Bell state with a certain probablility. We also consider two further protocols, one based on simple repetition and the other based on successive measurements and conditional resetting, and show that the cumulative probability of creating a Bell state between Alice and Bob tends to unity.Comment: Added seven references, clarified argument for eqn (16