Photoelectrocatalytic humic acid degradation kinetics and effect of pH,applied potential and inorganic ions

This study addresses the removal of humic acid (HA) dissolved in an aqueous medium by a photoelectrocatalytic process. UV₂₅₄ removal and the degradation of color (Vis₄₀₀) followed pseudo‐first order kinetics. Rate constants were 1.1 × 10^?1 min^?1, 8.3 × 10^?2 min^?1 and 2.49 × 10^?2 min^?1 (R² > 0.97) for UV₂₅₄ degradation and 1.7 × 10^?1 min^?1, 6.5 × 10^?2 min^?1 and 2.0 × 10^?2 min^?1 for color removal from 5 mg dm^?3, 10 mg dm^?3 and 25 mg dm^?3 HA respectively. Following a 2 h irradiation time, 96% of the color, 98% of the humic acid and 85% of the total organic carbon (TOC) was removed from an initial 25 mg dm^?3 HA solution in the photoanode cell. Photocatalytic removal on the same photoanode was also studied in order to compare the two methods of degradation. Results showed that the photoelectrocatalytic method was much more effective than the photocatalytic method especially at high pH values and with respect to UV₂₅₄ removal. The effect of other important reaction variables, eg pH, external potential and electrolyte concentration, on the photoelectrocatalytic HA degradation was also studied. Copyright © 2003 Society of Chemical Industry     

Functional polyamides. 3. Synthesis and chelating properties of a new poly(amide thioether)

Polymerization of β,β′-(ethylenedithio)dipropionitrile

1 IUPAC name: 4,7-dithiadecane dinitrile.

with formaldehyde in the presence of sulfuric acid was carried out in order to permit the synthesis of polymides containing thioether groups. The obtained poly(amide thioether)s were characterized; they coordinate mercury (II) with a high degree of selectivity.     

A combo technology of autotrophic and heterotrophic denitrification processes for groundwater treatment

In this study,a sequential process (heterotrophic up-flow column and completely mixed membrane bioreactors) was proposed combining advantages of the both processes.The system was operated for 249 days with simulated and real groundwater for nitrate removal at concentrations varying from 25 to 145 mg·L-1 NO3-N.The contribution of heterotrophic process to total nitrate removal in the system was controlled by dozing the ethanol considering the nitrate concentration.By this way,sulfur based autotrophic denitrification rate was decreased and the effluent sulfate concentrations were controlled.The alkalinity requirement in the autotrophic process was produced in the heterotrophic reactor,and the system was operated without alkalinity supplementation.Throughout the study,the chemical oxygen demand in the heterotrophic reactor effluent was (23.7 ± 22) mg·L-1 and it was further decreased to(7.5 ± 7.2) mg·L-1 in the system effluent,corresponding to a 70％ reduction.In the last period of the study,the real groundwater containing 145 mg·L-1 NO3-N was completely removed.Membrane was operated without chemical washing in the first 114 days.Between days 115-249 weekly chemical washing was required.     

Topology-Aware Multiple Routing Configurations for Fault Tolerant Networking

Real-time services require reliable and fault tolerant communication networks to support their stringent Quality of Service requirements. Multi Topology Routing based IP Fast Re-route (MT-IPFRR) technologies provide seamless forwarding of IP packets during network failures by constructing virtual topologies (VTs) to re-route the disrupted traffic. Multiple Routing Configurations (MRC) is a widely studied MT-IPFRR technique. In this paper, we propose two heuristics, namely mMRC-1 and mMRC-2, to reduce the number of VTs required by the MRC to provide full coverage for single link/node failures, and hence, to decrease its operational complexity. Both heuristics are designed to construct more robust VTs against network partitioning by taking their topological characteristics into consideration. We perform extensive experiments on 3200 topologies with diverse structural properties using our automated topology generation and analysis tool. Numerical results show that the amount of reductions in VT requirements get higher up to 31.84 %, as the networks tend to have more hub nodes whose degree is much higher than the rest of the network.     

Physical and Mechanical Properties of PP Composites based on Different Types of Lignocellulosic Fillers

The presents preparation and characterization of different types of lignocellulosic fillers (pine wood sawdust/ walnut shell flour/ black rice husk powder) reinforced polypropylene composites were presented. The effect of MAPP as coupling agent (4wt%) on the physical and mechanical properties was also investigated. Polypropylene composites were prepared at different rates of filler/matrix (wt%) by using extrusion (for melt blending) and hot compression molding process. Maximum values of tensile and flexural strength were obtained as 26.1 and 43.4 MPa, respectively, whereas the elongation at break value was 4.11% at 10% pine wood sawdust reinforced PP. Tensile and flexural modulus of composites reached the maximum values as 3855 and 3633 MPa with the composite of 30% walnut shell flour reinforced PP. Characterization of composites was carried out by using tensile test, flexural test, FT-IR, and SEM.     

Synthesis and Characterization of PEG-Sr Hexaferrite by Sol–Gel Conversion

Sr-M-type hexagonal ferrites have been prepared via a sol?Cgel route, and the effects of addition of different molecular weight polyethylene glycol (PEG) into the sol solutions on the static magnetic properties and particle morphology have been studied. Crystalline phases of the samples were determined by XRD analysis. FT-IR and TG analyses were used to prove the presence of PEG on SrFe₁₂O₁₉. The results showed that adding PEG with different molecular weight into the sol solutions affected the formation mechanism of SrFe₁₂O₁₉. Sr-M precursors prepared by various PEG types show different magnetic behaviors after pre-calcination at 150?^°C. This discrepancy is explained by the formation of a different phase during the synthesis of SrM particles.     

Transcranial Magnetic Stimulation of the Supplementary Motor Area in the Treatment of Obsessive-Compulsive Disorder: A Multi-Site Study

Recently, strategies beyond pharmacological and psychological treatments have been developed for the management of obsessive-compulsive disorder (OCD). Specifically, repetitive transcranial magnetic stimulation (rTMS) has been employed as an adjunctive treatment in cases of treatment-refractory OCD. Here, we investigate six weeks of low frequency rTMS, applied bilaterally and simultaneously over the sensory motor area, in OCD patients in a randomized, double-blind placebo-controlled clinical trial. Twenty-two participants were randomly enrolled into the treatment (ACTIVE = 10) or placebo (SHAM = 12) groups. At each of seven visits (baseline; day 1 and weeks 2, 4, and 6 of treatment; and two and six weeks after treatment) the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was administered. At the end of the six weeks of rTMS, patients in the ACTIVE group showed a clinically significant decrease in Y-BOCS scores compared to both the baseline and the SHAM group. This effect was maintained six weeks following the end of rTMS treatment. Therefore, in this sample, rTMS appeared to significantly improve the OCD symptoms of the treated patients beyond the treatment window. More studies need to be conducted to determine the generalizability of these findings and to define the duration of rTMS’ clinical effect on the Y-BOCS. Clinical Trial Registration Number (NCT) at www.clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT00616486","term_id":"NCT00616486"}}NCT00616486.     

Filtering of satellite images in geological lineament analyses: An application to a fault zone in Central Turkey

Lineament extraction and analysis is one of the routines in mapping large areas using remotely-sensed data, most of which is the satellite images. In this study, we aimed to test different lineament extraction techniques including single band, multiband enhancements and spatial domain filtering techniques. A fast algorithm has been developed for time and cost limited surveys in an area with known dominant and/or any selected orientation of lineaments. During the study for single band analysis, histogram equalization and stretching, for multiband, Principal Components Analysis (PCA) and for spatial domain filtering Prewitt and Sobel filters are utilized. Furthermore, we have developed a new algorithm which consists of a combination of large smoothing filters and gradient filters, in order to get rid of the artificial lineaments which are out of interest and to determine discontinuous and/or closely spaced regional lineaments. The results are as follows; the number of lineaments and their total lengths are 218 285.3 km using the single band; 255 343.9 km in multiband enhancements, and 347644.9 km in the combination of spatial domain filtering including our algorithm. The 59.17 per cent increase in the number of lineaments and the 126.04 per cent increase in the total lengths indicate that a combination of spatial domain filters is the most cost-time efficient algorithm in lineament analyses.     

Effect of Synthesis and Sintering Conditions on the Thermoelectric Properties of n-Doped Mg2Si

Magnesium silicide (Mg₂Si)-based alloys are promising candidates for thermoelectric (TE) energy conversion in the middle–high temperature range. The detrimental effect of the presence of MgO on the TE properties of Mg₂Si based materials is widely known. For this reason, the conditions used for synthesis and sintering were optimized to limit oxygen contamination. The effect of Bi doping on the TE performance of dense Mg₂Si materials was also investigated. Synthesis was performed by ball milling in an inert atmosphere starting from commercial Mg₂Si powder and Bi powder. The samples were consolidated, by spark plasma sintering, to a density >95%. The morphology, and the composition and crystal structure of samples were characterized by field-emission scanning electronic microscopy and x-ray diffraction, respectively. Moreover, determination of Seebeck coefficients and measurement of electrical and thermal conductivity were performed for all the samples. Mg₂Si with 0.1 mol% Bi doping had a ZT value of 0.81, indicative of the potential of this method for fabrication of n-type bulk material with good TE performance.