A new application of Hydroxyapatite extracted from dromedary bone: Adsorptive removal of Congo red from aqueous solution

The aim of this paper is to evaluate the efficiency of the natural hydroxyapatite powder for anionic dye (Congo red) elimination from water and optimization of adsorption process parameters that are contact time (0-360 min), solution pH (4-9), initial dye concentration (400-2400 mg/l), and adsorbent dosage (0.4-20 g/l). Natural hydroxyapatite with high surface area was prepared from animal agriculture waste dromedary bone. X-ray diffraction, transmission electron microscopy, transform infrared spectroscopy, and elemental analysis characterizations of the powder prepared show a hexagonal structure, the irregular form of hydroxyapatite and presence of other elements as trace element. The results of adsorption tests demonstrated the high efficiency of natural hydroxyapatite for removal of Congo red from water solution whose maximum experimental capacity adsorption of Congo red by natural hydroxyapatite is 900 mg/g at pH 4.5, equilibrium time 240 min and adsorbent dosage 2 g/l. According to the correlation coefficient value, the pseudo-second order kinetic model identified the sorption mechanism of pollutant used on natural hydroxyapatite. The Freundlich isotherm is the best representative theoretical model of the dye molecules’ adsorption on the natural hydroxyapatite support.     

Atmospheric flows of semi-volatile organic pollutants to the Great Lakes estimated by the United States' Integrated Atmospheric Deposition and Canada's Great Lakes Basin Monitoring and Surveillance Networks

We calculated the wet and dry deposition, vapor absorption, and volatilization flows (in kg/yr) of seven polychlorinated biphenyls (PCBs), nine organochlorine pesticides, and two polycyclic aromatic hydrocarbons (PAHs) into and out of the Great Lakes during 2010–2015 (inclusive). Particle, vapor, and precipitation concentrations from five rural and remote stations (one site on each lake) and two urban sites, operated by the United States and Canada, were used for the flow calculations. Output from the water to the air was the most important process for PCBs, chlordanes, and p,p′-DDE. The flows of endosulfan, p,p′-DDT, and phenanthrene were dominated by vapor absorption from the air to the water. The flow of benzo[a]pyrene was controlled by wet and dry deposition to the water. The flows of the hexachlorocyclohexanes (HCHs) into and out of the lakes were about equal, indicating air-water equilibrium for these compounds. Among the lakes, Lakes Superior and Erie had the highest input and output flows. The input and output flows for the five lakes were decreasing with halving times of 1–10 years and 10–40 years, respectively. Most chemicals had seasonal variations in their flows, with maximum inputs in the summer and maximum outputs in the fall. The flows of PCBs and PAHs into Lakes Michigan and Erie were associated with Chicago and Cleveland, respectively. Combining our data with previous data over the period 1992–2015, we estimated that the input flows of most of these chemicals have significantly decreased, but the output flows do not show consistent trends.     

The Cognitive Interview: A meta-analytic review and study space analysis of the past 25 years.

The Cognitive Interview (CI) is a well-established protocol for interviewing witnesses. The current article presents a study space analysis of laboratory studies of the CI together with an empirical meta-analysis summarizing the past 25 years of research. The study space comprises 57 published articles (65 experiments) on the CI, providing an assessment of the boundary conditions underlying the analysis and application of this interview protocol. The current meta-analysis includes 46 published articles, including 20 articles published since the last meta-analysis conducted a decade earlier (K?hnken, Milne, Memon, & Bull, 1999). Reassuringly for practitioners, the findings of the original meta-analysis were replicated with a large and significant increase in correct details and a small increase in errors. In addition we found that there were no differences in the rate at which details are confabulated. Importantly, the effect sizes were unaffected by the inclusion of recent studies using modified versions of the CI. The CI appeared to benefit older adult witnesses even more than younger adults. We highlight trends and gaps in research and discuss how our findings can inform policy and training decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Low temperature synthesis of <Emphasis Type="Italic">Manganese tungstate</Emphasis> nanoflowers with antibacterial potential: Future material for water purification

Pure water is the fundamental requisite for human life. The water has been recycled naturally but not in an adequate amount for consumption. Nanotechnology with extraordinary applications provides competent ways for the decontamination of contaminated water. In the present study MnWO₄ nanoflowers endorsed with inherent antibacterial activity were successfully synthesized by facile hydrothermal approach. XRD, SEM, EDX spectroscopy and UVDRS were used to characterize the as-synthesized nanoflowers. Gram negative Escherichia coli ATCC 52922 bacterium was used as model organism to test antibacterial activity of as-synthesized MnWO₄ nanoflowers. This study was conducted to optimize minimum concentration of MnWO₄ nanoflowers and maximum contact time required to achieve complete inactivation of bacteria present in contaminated water. Minimum inhibitory concentration (MIC) of MnWO₄ nanoflowers was found to be 10 μg/ml. The assessment and interpretation of bacterial viability was done using dual fluorescent staining. The synthesized 3D-nanoflowers were found as potent bactericides. Thus, MnWO₄ nanoflowers emerged to be very good future material for disinfection of biological pollutants present in the contaminated water reservoirs and as an anti-biofouling agent.     

On the "general acceptance" of eyewitness testimony research: A new survey of the experts.

In light of recent advances, this study updated a prior survey of eyewitness experts (S. M. Kassin, P. C. Ellsworth, & V. L. Smith, 1989). Sixty-four psychologists were asked about their courtroom experiences and opinions on 30 eyewitness phenomena. By an agreement rate of at least 80%, there was a strong consensus that the following phenomena are sufficiently reliable to present in court: the wording of questions, lineup instructions, confidence malleability, mug-shot-induced bias, postevent information, child witness suggestibility, attitudes and expectations, hypnotic suggestibility, alcoholic intoxication, the cross-race bias, weapon focus, the accuracy–confidence correlation, the forgetting curve, exposure time, presentation format, and unconscious transference. Results also indicate that these experts set high standards before agreeing to testify. Despite limitations, these results should help to shape expert testimony so that it more accurately represents opinions in the scientific community. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of a redox-modified clay mineral with respect to its suitability as a barrier in radioactive waste confinement

Engineered barriers for high-level nuclear waste (HLW) consist of excavated repositories in sub-surface rock formations where canisters holding the radionuclide are stored. Clay minerals, particularly the swelling 2:1 types, are used as backfill material, both in the canisters and in the bore hole, in order to prevent radionuclide transport to surrounding groundwater. One of the most important risks that can occur is the corrosion of the canister, which could be coupled with reduction of iron (Fe) in the clay structure. Such changes could greatly decrease the long-term stability of the clay and, consequently, of the barriers themselves. In order to test the potential effects of such redox interactions, an Fe-bearing clay mineral from a commercial source located in the Kutch region, India, was selected for study. This particular mineral is one of the candidate clay minerals to serve as such a barrier material, and is the one with the largest structural Fe content. Results from it should, therefore, provide maximum insight into the potential effects of redox interactions between the barrier and its surroundings. The unaltered clay was characterized by X-ray powder diffractometry (XRD), thermal gravimetric analysis (TGA/DTGA), Fourier-transform infrared (FTIR) spectroscopy, and variable-temperature Mössbauer spectroscopy. The chemically reduced and reoxidized forms of the clay were characterized by variable-temperature Mössbauer spectroscopy and chemical analysis. In the unaltered state the clay is comprised of smectite, maghemite, superparamagnetic goethite, and hematite, with a possible trace of kaolinite. In the reduced state the Fe (oxyhydr)oxides were dissolved. Upon reoxidation no six-line pattern was observed, indicating that the Fe remained only in the structure of the silicates. The final structure of the reduced–reoxidized clay contained more defects than the original clay, as revealed by greater quadrupole splitting values for structural Fe(III) in the clay. These findings indicate that upon exposure to natural redox cycles the Kutch clay could undergo permanent changes in its mineralogical composition and clay mineral structure, but further study is required to ascertain the effects that such changes would have on its long-term stability as a barrier material.     

Electrolyte—solvent interaction in the dipolar aprotic solvent dimethyl sulphoxide at 25°C

Conductance measurements are reported for s-alkylisothiouronium bromide, iodide and picrate salts in the dipolar aprotic solvent DMSO at 25°C. The data were analysed by Fuoss's equation (1975–1980) for 1:1 electrolytes, from which the values of Λ₀, the Gurney's cosphere diameter R and K_A are obtained. The results are discussed in the light of the recorded values of the constants K_R and K_S and the free energy term G_s.     

Advanced modeling and control of wind conversion systems based on hybrid generators using fractional order controllers

The focus of this study is on modeling and management of a Wind Energy Conversion System (WECS) based on a Hybrid Excitation Synchronous Generator (HESG). Using a wind simulator, two controllers, CRONE and H_∞, are evaluated for Maximum Power Point Tracking (MPPT) and optimal rotation speed. The results show the CRONE controller's higher tracking capability, and robustness tests investigate the influence of parametric uncertainty. Space harmonic effects, commutation effects, and turbine shaft flexibility are all addressed in the sophisticated models. The introduction of Fractional Order Proportional-Integral (FOPI) control for MPPT is a game changer. Although fractional calculus-based accuracy and robustness are uncommon in WECS, they show promise for emissions reduction and increased energy efficiency. This work validates a dependable control approach inside an isolated HESG-based WECS's power-maximizing range. Extensive investigation of the parameters impacting FOPI control efficiency yields useful insights for effective MPPT control. A variable-speed wind turbine (WT) is linked to a HESG through a multiplier, with a controller controlling generator coil excitation voltages and a rectifier connecting the WECS to a load. A thorough 3 kW HESG electrical model that includes generator space harmonics and converter commutation effects is among the contributions. For HESG-based WECS stability, frequency analysis finds important resonant and anti-resonant frequencies. These issues are addressed by a FOPI control technique, which ensures system stability and performance. The necessity of exact frequency analysis in HESG-based WECS is highlighted by a step-by-step controller parameter tuning approach.