Structural and Dielectrical Properties of Ag- and Ba-Substituted Hydroxyapatites

Ag- and Ba-doped hydroxyapatite (HAp) samples were synthesized by sol–gel method. The crystallite sizes for all the samples were found to vary from 26 to 39 nm. Neither Ag nor Ba did result in dramatic changes in the morphology of all the samples, and the Ca/P molar ratio was varied. The dielectric parameters of the samples were changed with the dopant content. The maximum and minimum values of the dielectric constant were observed for 2.0 %Ba-HAp and 0.5 %Ba-HAp samples. The alternating current conductivity indicates that all the samples exhibit the insulator behavior. The results of the biological tests revealed that Ag-containing samples have an antimicrobial activity, while no antimicrobial activity was detected for both HAp and Ba-doped HAp samples.     

Antibody purification from human plasma by metal‐chelated affinity membranes

The aim of this study is to investigate in detail the feasibility of poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐(L )‐histidine methyl ester), PHEMAH membranes for purification of immunoglobulin G (IgG) from human plasma. PHEMAH membranes were prepared by photo‐polymerization technique. Then, Zn²⁺, Ni²⁺, Co²⁺, and Cu²⁺ ions were chelated directly on the PHEMAH membranes. Elemental analysis assay was performed to determine the nitrogen content and polymerized MAH was calculated as 168.5 μmol/g. The nonspecific IgG adsorption onto the plain PHEMA membranes was negligible (about 0.25 mg/mL). A remarkable increase in the IgG adsorption capacities were achieved from human plasma with PHEMAH membranes (up to 68.4 mg/mL). Further increase was observed with the metal‐chelated PHEMAH membranes (up to 118 mg/mL). The metal‐chelate affinity membranes allowed the one‐step separation of IgG from human plasma. The binding range of metal ions for surface histidines from human plasma followed the order: Cu²⁺ > Ni²⁺ > Zn²⁺ > Co²⁺. Adsorbed IgG was eluted using 250 mM EDTA with a purity of 94.1%. IgG molecules could be repeatedly adsorbed and eluted with the metal‐chelated PHEMAH membranes without noticeable loss in their IgG adsorption capacity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The removal of Cr(VI) through polymeric supported liquid membrane by using calix[4]arene as a carrier

In this work, the transport and removal of Cr(VI) were achieved through supported liquid membrane (SLM) by using a 5,17, di-tert-butyl-11,23-bis[(1,4-dioxa-8-azaspiro [4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene carrier, dissolved in 2-nitrophenyl octyl ether dichloromethane. The studied parameters are the solvent effect in the membrane phase, the effect of carrier concentration, and the acid type in the donor phase. The Celgard 2500 was used as a membrane support. We used the Danesi mass transfer model to calculate the permeability coefficients for each studied parameter. In addition, AFM and SEM techniques were used to characterize the surface morphology of the prepared Celgard 2500 membrane that included the calix[4]arene carrier.     

V2O5–polyimide hybrid material: synthesis,characterization, and sulfur removal properties in fuels

We describe the synthesis of a new sorbent material for desulfurization of gasoline, which is composed of polyimide (PI) and vanadium pentoxide via the solution direct-dispersing method. The highly porous PI–V₂O₅ hybrid materials, containing different concentrations of V₂O₅ ranging from 1 to 10 wt%, were prepared from pyromellitic dianhydride, 2,4,6-triaminopyrimidine, and vanadium pentoxide. The produced PI–V₂O₅ composites were investigated by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscope, and thermal analysis techniques. The effect of V₂O₅ on the sulfur removal properties as well as the thermal stability and porous structure of composites were investigated. Then the obtained material was investigated to determine their sorption characteristics for sulfur compounds from fuels. By use of this material, 91 wt% of the sulfur content was removed from sulfur-containing standard oil. An economic sensitive and simple method for the removal and separation of sulfur in fuel samples, using an PI–V₂O₅ packed mini chromatographic column, was established.     

Preparation and Thermodynamic Properties of Camphene/Stearic Acid Composites as Phase-Change Materials in Buildings

In this study, a series of shape-stabilized phase-change materials (PCMs) of camphene/stearic acid (CS) were prepared and their thermal properties were measured by differential scanning calorimetry. The results indicated that the mixture consisting of 60 mass% camphene and 40 mass% stearic acid is the most favorable as a PCM, in terms of the phase-change temperature and latent heat. Thereafter, the CS was absorbed in fly ash, pyroclastic, barite, and marble powder, which acts as a supporting material, to prepare four kinds of composite-based PCMs. DSC, FT-IR, and scanning electron microscopy measurements were made to investigate the structures and properties of the PCMs. DSC results showed that the latent heats of melting and freezing of the composite PCMs were sharply decreased. Morphology and structural characterization revealed that, in form-stable PCMs, the dispersion of the supporting materials in the camphene/stearic acid matrix is homogeneous and there is no chemical interaction between the CS and composites. The composite PCMs showed excellent thermal stabilities and reliabilities, when their phase-change temperatures were concerned. These indicate that the prepared composite-based PCMs are suitable for thermal energy storage because of their applicable temperature range, thermal reliability, and chemical stability.     

Utilization potential lignocellulosic waste biomass to produce carbon support by using new activation reagent (H3BO3 and SrCl2): structural and adsorptive properties

ABSTRACT

Activated carbons series were produced from the orange peel by chemical activation using strontium chloride (SrCl₂) and boric acid (H₃BO₃). The activation temperature effects and type of activation reagents on the surface and chemical properties of activated carbon have been investigated. The surface area of the activated carbons is 577 and 290 m² g^?1 for H₃BO₃ and SrCl₂ activation_, respectively. An increase in the temperature for both H₃BO₃ and SrCl₂ led to a decrease in the yields of the activated carbons. The yield of H₃BO₃ series is higher than the yield of SrCl₂. The obtained activated carbons were heteroporous with the mesopore. Orange peel can be used alternative waste biomass for the mesoporous activated carbon productions. Samples were characterized by XRD, SEM, FTIR, and TGA analysis.     

A CASE STUDY FOR CONTROL STRUCTURE SELECTION: CHLORINATION STAGE IN THE BLEACHING PROCESS OF A PULP AND PAPER PLANT

The minimization of chlorinated organic compounds in the effluents of the chlorination unit of a pulp mill is proposed by the use of a control structure for the chlorination unit. Bleached pulp properties are related to the unbleached pulp properties: lignin content, brightness, and viscosity, as well as the amount of chlorinated organics in the bleachery effluent. The best feasible control pairings are studied by RGA and SVD methods. Kappa number of the bleached pulp (a measure of lignin content) and percent consistency of the pulp to be bleached; residual chlorine (which affects the amount of chlorinated organics discharged) and percent chlorine/pulp ratio adapted in the chlorination stage; and exit pulp viscosity (which directly affects strength and tear resistance of the paper) and residence time in the chlorinator are chosen to be the best pairings.     

Cross‐layer MAC design for location‐aware wireless sensor networks

In this paper, we propose an optimization of MAC protocol design for wireless sensor networks, that accounts for cross‐layering information, in terms of location accuracy for nodes and residual energy levels. In our proposed solution we encode this cross‐layer information within a decreasing backoff function in the MAC. The protocol is optimized by appropriately selecting priority window lengths, and we have shown that accurate cross‐layer information plays a crucial role in achieving an optimal performance at the MAC layer level. The estimation accuracy can be characterized spatially using a location reliability probability distribution function. We show that this distribution function greatly influences the design of the optimal backoff window parameters, and the overall throughput performance of the MAC protocol. Copyright © 2010 John Wiley & Sons, Ltd.     

Targeted use of LEDs in improvement of production efficiency through phytochemical enrichment

Based on available literature, ecology and economy of light emitting diode (LED) lights in plant foods production were assessed and compared to high pressure sodium (HPS) and compact fluorescent light (CFL) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco‐friendly lighting devices. The present review indicates also that LEDs have many practical benefits compared to other lamp types. In addition, they are applicable in many purposes in plant foods production. The main focus of the review is the targeted use of LEDs in order to enrich phytochemicals in plants. This is an expedient to massive improvement in production efficiency, since it diminishes the number of plants per phytochemical unit. Consequently, any other production costs (e.g. growing space, water, nutrient and transport) may be reduced markedly. Finally, 24 research articles published between 2013 and 2017 were reviewed for targeted use of LEDs in the specific, i.e. blue range (400–500 nm) of spectrum. The articles indicate that blue light is efficient in enhancing the accumulation of health beneficial phytochemicals in various species. The finding is important for global food production. © 2017 Society of Chemical Industry