Biosorption of nickel ions from aqueous solutions by natural and modified peanut husks: equilibrium and kinetics

The toxicity and non‐biodegradation of heavy metals, as well as their tendency to accumulate in the soils, water resources and the living organisms, makes them the significant environmental pollutants. Therefore, the reduction and elimination of heavy metal ions from aqueous systems is very important from the ecological, nutritional and environmental reasons. The aim of this study is to investigate whether the natural peanut husks, an agricultural waste, and their chemically modified form are capable to remove Ni(II) ions from aqueous solutions using batch method and to compare their efficiency. The effects of the mass of the natural peanut husks and the initial pH of the solution were studied to find the optimal conditions for maximal removal of Ni(II) ions. MATLAB/Curve Fitting Toolbox was implemented to determine the adequate adsorption isotherm as well as to optimise the equilibrium state of the investigated systems.     

Geothermal energy in agriculture in Yugoslavia

SFR Yugoslavia has natural hot water springs practically all over its territory, indicating the presence of geothermal reservoirs underground. There is no final estimate of how much energy can be expected from this new resource, except for figures based on the results of studies and investigations.The first use of geothermal energy in Yugoslavia in numerous spas dates back to the 19th century. Some remarkable examples of central heating are known, but the most widespread use is in agriculture (in greenhouse heating, farm heating and drying of agricultural products).     

The Complexity of Modellability in Finite and Computable Signatures of a Constraint Logic for Head-Driven Phrase Structure Grammar

The SRL (speciate re-entrant logic) of King (1989) is a sound, complete and decidable logic designed specifically to support formalisms for the HPSG (head-driven phrase structure grammar) of Pollard and Sag (1994). The SRL notion of modellability in a signature is particularly important for HPSG, and the present paper modifies an elegant method due to Blackburn and Spaan (1993) in order to prove that

Expected utility analysis of infinite compound lotteries

Lotteries can be used to model alternatives with uncertain outcomes. Decision theory uses compound ordinary lotteries to represent a structure of lotteries within lotteries, but can only rank the finite compound lottery structure. We expand upon this approach to introduce solutions for infinite compound ordinary lotteries (ICOL). We describe a novel procedure to simplify any ICOL as much as possible to a maximum reduced ICOL, which is not a unique representation. We limit our discussion to ICOLs of first order, which are defined as maximum reduced ICOLs with a single maximum reduced ICOL in their direct outcome. Two special cases of ICOLs of first order are discussed. These are recursive and semi-recursive ICOLs. We provide an analytical approach to find the expected utility of recursive ICOLs, and a numerical algorithm for semi-recursive ICOLs. We demonstrate our solution methods by evaluating example decision problems involving: a randomizing device with unsuccessful trials, the St. Petersburg paradox, and training with virtual reality.     

Morphology,structure, and properties of metal oxide/polymer nanocomposite electrospun mats

Adding nanoparticles into polymer solutions before electrospinning creates unique hierarchical morphologies dispersed throughout small diameter nanoparticle‐polymeric fibers. Effects of polymer composition, nanoparticle (NP) type, loading, and electrospinning voltage conditions were studied. As examples, indium, iron, and titanium oxide engineered nanoparticles (NPs) were dispersed into polyvinylpyrrolidone or polystyrene and electrospun. NP loadings below 5 wt % did not affect critical voltage required for Taylor cone formation, whereas higher NP loadings require higher critical voltages. Polymeric fiber thickness and macroscopic morphology is not impacted by up to 5 wt % NP loadings, and NP dispersion throughout the fibers were similar to their dispersion in initial polymer suspension. NP loadings above 5 wt % increased viscosity, which decrease subsequent fiber diameter. Experiments in water containing inorganic and organic pollutants in water demonstrate that the polymer is largely nonporous. This work enables design of multifunctional nanomaterial‐polymer composite fibers for wide‐ranging applications such as water and air treatment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43811.     

Water quality and yield from polymer electrolyte membrane fuel cells

Water and energy production and demand are interconnected. Polymer electrolyte membrane fuel cells (PEMFCs) are devices that produce water while they generate power using hydrogen as a fuel. Herein, a lab-scale PEMFC was operated under variable experimental conditions, such as membrane chemical composition, operating temperature, operating current density, external humidification water quality, and fuel cell materials, to investigate the quality and quantity of the water produced. At each experimental condition the quantity and quality of the recovered product water was evaluated in the context of its suitability for use as drinking water. The results indicate that water produced by PEMFCs needs some treatment to comply with the US Environmental Protection Agency (US EPA) drinking water standards and World Health Organization (WHO) guidelines for drinking water quality. The measurements show a correlation between the fluoride concentration and the total organic matter (TOC) in the water samples when the fuel cell is operated with self-humidified membranes. A water collection efficiency up to 70% was obtained.     

Simultaneous removal of perchlorate and arsenate by ion-exchange media modified with nanostructured iron (hydr)oxide

Hybrid ion-exchange (HIX) media for simultaneous removal of arsenate and perchlorate were prepared by impregnation of non-crystalline iron (hydr)oxide nanoparticles onto strong base ion-exchange (IX) resins using two different chemical treatment techniques. In situ precipitation of Fe(III) (M treatment) resulted in the formation of sphere-like clusters of nanomaterials with diameters of approximately 5nm, while KMnO4/Fe(II) treatments yielded rod-like nanomaterials with diameters of 10-50nm inside the pores of the media. The iron content of most HIX media was >10% of dry weight. The HIX media prepared via the M treatment method consistently exhibited greater arsenate adsorption capacity. The fitted Freundlich adsorption intensity parameters (q=K x C(E)(1/n)) for arsenate (1/n<0.6) indicated favorable adsorption trends. The K values ranged between 2.5 and 34.7mgAs/gdry resin and were generally higher for the M treated media in comparison to the permanganate treated media. The separation factors for perchlorate over chloride (alpha(Cl-)(ClO4-)) for the HIX media were lower than its untreated counterparts. The HIX prepared via the M treatment, had higher alpha(Cl-)(ClO4-) than the HIX obtained by the KMnO(4)/Fe(II) treatments suggesting that permanganate may adversely impact the ion-exchange base media. Short bed adsorber (SBA) tests demonstrated that the mass transport kinetics for both ions are adequately rapid to permit simultaneous removal using HIX media in a fixed bed reactor.     

SOME MECHANICAL CHARACTERISTICS OF NITROGEN STRUCTURAL STEELS

In this paper, test conditions and microstructural factors have been investigated for newly developed nitrogen steels at load rates and test temperatures suitable for future operating conditions. Static tests have been carried out at ε～ 10^?4 s^-1 and dynamic tests at ε～ 10² s^?1. Different test temperatures enable fracture mechanisms and fracture toughness variations to be studied. Anisotropy of some characteristics in the initial (non-heat-treated) state, together with heat treatment effects and structural changes under two load rates have been analysed. Fracture appearance transition temperature (FATT) values have been obtained from absorbed energy and fracture surface crystallinity values. Using yield strength and fracture toughness data, an estimate has been made of critical crack lengths for unstable fracture.     

Promoting Hydroxyl Radical Production during Ozonation of Municipal Wastewater

Hydroxyl radical (HO^?) production during ozonation of municipal wastewater was investigated with and without liquid or solid-phase promoters. For liquid-phase promoters, an “ozone dose threshold” was observed, below which addition of H₂O₂ yielded no discernible increase in the rate of HO^? production. This threshold occurs because ozonation of bulk organics in wastewater promotes HO^? due to the presence of ambient promoters. Although solid-phase catalysts are reported to promote oxidation of contaminants, ozonation of effluent over TiO₂ or GAC was no more effective on trace organic removal than over inert surfaces.