Adsorptive removal of phosphate from aqueous solutions using raw and calcinated dolomite

This study explored the feasibility of utilizing raw and calcinated dolomite under CO2 atmosphere for phosphate removal in laboratory experiments. The experimental work emphasized the evaluation of phosphate adsorption characteristics of this adsorbent material. Studies were conducted to delineate the effect of contact time, initial phosphate concentration, temperature, pH, stirring speed, adsorbent dose and calcination temperature. Phosphate removal decreased with increasing temperature and slightly increased with increasing of pH. The observed decrease in the adsorption capacity with increase of the temperature from 20 to 40 and to 60 degrees C indicates that the low temperatures favor the phosphate removal by adsorption onto dolomite. Phosphate removal was seen to decrease with increasing calcination temperature due to the structural changes occurring in the structure and pore size distribution of dolomite samples during calcination. The experimental data obtained were applied to the Freundlich, Langmuir, BET, Halsey, Harkins-Jura, Smith and Henderson isotherm equations to test the fit of these equations to raw and calcinated dolomite samples. By considering the experimental results and adsorption models applied in this study, it can be concluded that adsorption of phosphate occurs predominantly through physical interactions, and the dolomite sample has a heteroporous structure. The large values of the constants for Henderson equation and the high value of y(m) obtained from BET equation indicate the microporous structure is more stable in raw and calcinated dolomite samples.     

Some Properties of Digital Covering Spaces

In this paper, we study digital versions of some properties of covering spaces from algebraic topology. Among our results are some that correct or improve upon the presentation of assertions in earlier papers (Boxer and Karaca in J. Math. Imaging Vis. 32:23–29, 2008; Han in Inf. Sci. 177:3731–3748, 2007; Han in Inf. Sci. 178:550–561, 2008).     

Calculating Roller Requirements for Chip Seal Projects

This paper details a mathematical algorithm to determine the required number of rollers for a chip seal project’s equipment spread based on maximizing the asphalt distributor’s production and adhering to specified roller time requirements. The paper reports one of the findings of a three-year constructability review of the Texas Department of Transportation’s statewide seal coat program. One of the findings of that study was that there was a correlation between the number of rollers used on a job and the loss of aggregate after construction was completed. The roller is the tool used to seat the aggregate and create embedment in the asphaltic binder. Thus, the failure to achieve design embedment depth is primarily a function of achieving quality control requirements for roller linger time. The paper illustrates a straightforward method to calculate the required number rollers to achieve both maximum productivity for the chip seal paving train and to ensure a uniform distribution of roller coverage across the width of the shot. The paper concludes that designing the roller spread is in the best interests of both the chip seal contractor and the owner.     

Application Oriented Multi Criteria Optimization in WSNs Using on AHP

With the increasing number and variety of Wireless Sensor Network (WSN) applications the need to define a suitable protocol design model that fits their specific requirements and operation has become even more pressing. The traditional methods and the well known OSI layered model prove to be inadequate for WSNs. Utilizing cross layer interactions on the other hand leads to increased efficiency in operation and prolonging the network lifetime. Similarly, proper optimization can even further add to improving the performance and reducing energy consumption in WSN. However there is no common ground to compare the suggested solutions or there is no well defined methodology for determining the optimization parameters for each specific case. In this paper we discuss two major issues: the first one is definition of optimization parameters for WSN and check for their consistency, the second one is how the suggested approach can be incorporated in a cross layer framework to provide adaptivity to different application requirements while maximizing the network performance and prolonging the network lifetime.     

Effects of enzymatic treatments on surface morphology and chemical structure of linen fabrics

In previous studies; effects of enzymatic treatments on linen fabrics have been mostly investigated in terms of wettability, sorption properties, whiteness-yellowness index, and K/S values after dyeing. However, surface chemistry and topography of enzyme-treated linen fabrics have not been reported enough. The aim of this work was to examine the effect of pectinase treatments on surface structure and chemical properties of greige linen fabrics by using instrumental techniques. After enzymatic treatment, adequate removal of noncellulosic impurities from the fiber surface has been proved by AFM images and O₁/C₁ ratio of the treated surface. Water drop test measurement and absorbance spectrographs of FTIR analysis have supported the results. It was observed that achievement in bioscouring is familiar to conventional alkaline scouring. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The effect of severe marforming on shape memory characteristics of a Ti-rich NiTi alloy processed using equal channel angular extrusion

A Ti-49.8 at. pct Ni alloy was severely deformed at three different temperatures using equal-channel angular extrusion (ECAE). Three deformation temperatures—room temperature (below the martensite finish temperature), 50 °C (below the austenite start temperature), and 150 °C (above the austenite finish temperature)—were selected such that the initial deforming phase (B2 austenite or B19’ martensite) and the initial governing deformation mechanism (martensite reorientation, stress-induced martensitic transformation, or dislocation slip in martensite) would be different. The X-ray analysis results revealed that all processed samples mostly contained a deformed martensitic phase, regardless of the initial deforming phase and the deformation mechanism. Although the martensite start temperature did not change, the austenite start temperature decreased significantly in all deformation conditions, probably because of the effect of the internal stress field caused by the deformed microstructure. All deformation conditions led to an increase in the strength levels and some deterioration of shape-memory characteristics. However, a subsequent low-temperature annealing treatment significantly improved pseudoelastic strain levels while preserving the ultrahigh strength levels. The sample deformed at room temperature followed by the low-temperature annealing resulted in the most promising strength and shape-memory characteristics under compression, such that a 5.3 pct shape-memory strain at a 2200 MPa strength level and a 3.3 pct pseudoelastic strain at a 1900 MPa strength level were achieved. The differences between the strength levels and the shape-memory characteristics after severe deformation at different temperatures were attributed to the different amounts of plastic deformation and the resulting deformation textures, since at each deformation temperature the deformation mechanism was different. It is concluded that the severe marforming using ECAE could easily improve strength levels of NiTi alloys while preserving the shape-memory and pseudoelasticity (PE) characteristics and, thus, improve the thermomechanical fatigue behavior. However, lower deformation temperatures are necessary to hinder formation of macroshear bands, and ECAE angles larger than 90 deg should be used to reduce the amount of strain applied in one pass.     

Remediation of fungicide residues on fresh produce by use of gaseous ozone

Ozone fumigation was explored as a means for degrading organic fungicide residues on fresh produce. Fungicides sorbed onto model abiotic glass surfaces or onto grape berries were fumigated separately in a flow-through chamber. Gaseous ozone at a constant concentration of 150 ± 10 ppmv (μL·L(-1)) selectively oxidized fungicides sorbed to model surfaces. Over 140 min, boscalid and iprodione levels did not change significantly based on a single-factor analysis of variance (ANOVA) at the 95% level of confidence (p = 0.05); however, pseudo-first-order losses resulted in observable rate constants of ozonolysis, k(ozonolysis) (min(-1)), of 0.0233 ± 0.0029 (t(1/2) ≈ 29.7 min), 0.0168 ± 0.0028 (t(1/2) ≈ 41.3 min), and 0.0127 ± 0.0010 (t(1/2) ≈ 54.6 min) for fenhexamid, cyprodinil, and pyrimethanil, respectively. The relative degradation of fungicides on berries at gaseous ozone concentrations of 900 ± 12 ppmv (μL·L(-1)) over 2 h was similar to that on glass; decreases in residue concentration were observed for only fenhexamid (～ 64%), cyprodinil (～ 38%), and pyrimethanil (～ 35%) with corresponding k(ozonolysis) (min(-1)) of 0.0085 ± 0.0021 (t(1/2) ≈ 81.5 min), 0.0039 ± 0.0008 (t(1/2) ≈ 177.7 min), and 0.0036 ± 0.0007 (t(1/2) ≈ 192.5 min). Heterogeneous rate constants of gaseous ozone reacting with a sorbed fungicide, k(O(3)) (M(-1)·min(-1)), were calculated for both surfaces and indicate losses proceed ～ 15-fold slower on grapes. The kinetics and mechanism of fungicide removal, supported by gas chromatography- and liquid chromatography-mass spectrometry product analyses, is discussed in the context of facilitating compliance with maximum residue level (MRL) tolerances for fresh produce.     

Ischemia/reperfusion injury in flow-through venous flaps

This study was designed to test the activity and feasibility of 5'-deoxy-5-fluorouridine (5'-DFUR) and cisplatin combination therapy in the treatment of advanced gastric cancer. Nineteen patients with inoperable and/or metastatic gastric cancer, which was histologically proven, were orally administered 5'-DFUR 1,200 mg/m2 on days 1 to 4 and days 15-18 combined with 70 mg/m2 of cisplatin being repeated every 4 weeks. Five partial responses (PRs) were achieved. Seven patients had stable disease and 6 progressed on therapy. The overall response rate was 27.7% (95% confidence interval: 9.69% to 53.5%). The median survival duration of all 18 patients was 25 weeks (9-64). The majority of patients had WHO grade I/II toxicity, but there was no treatment-related death. These data support that the combinations of oral 5'-DFUR and cisplatin are well tolerable and have a moderate activity with low toxicity in the treatment of advanced gastric cancer.     

Characterising high mass materials in heavy oil fractions by size exclusion chromatography and MALDI-mass spectrometry

Several petroleum vacuum residues and a Maya asphaltene have been examined using size exclusion chromatography (SEC), using 1-methyl-2-pyrrolidinone as eluent. Aliphatic components are not dissolved in this solvent. All the samples showed a bimodal distribution. Material under the early eluting peak, excluded from column porosity corresponded to apparently very large molecular masses. The later eluting peak corresponded to molecules with a smaller range of masses and was relatively intense. The material excluded from column porosity is concentrated in the heptane-insoluble fraction; the peak of this fraction corresponding to smaller molecules shifted to earlier times than was found for the whole sample. In UV-fluorescence spectrometry, the heptane-insoluble materials did not fluoresce strongly. Materials excluded from column porosity showed no fluorescence, indicating that UV-fluorescence based methods are unable to detect high mass materials. MALDI-mass spectrometry indicated a bimodal distribution for the Maya asphaltene with a mass range up to m/z 40,000. Comparison of the low mass range of the spectrum with the small-size molecules detected by SEC indicated broad agreement for masses up to about 5000 u. However, if the excluded peak of SEC corresponds to the higher mass range up to m/z 40,000, then it is likely that these molecules are adopting three-dimensional conformations. Data from the hydrocracking of heavy oils was used to confirm some of the outlined findings.