Extraction of americium and europium with functionalized calixarenes from alkaline solutions

Extraction of ²⁴¹Am and ¹⁵²Eu from alkaline carbonate solutions with solutions of functionalized calix[4]arenes and their nonmacrocyclic analogs in m-nitrobenzotrifluoride was studied. The dependence of the distribution ratios and separation factors of the radionuclides on pH of the aqueous phase in the interval from 9.8 to 13.5 and on the position and electronic nature of functional groups (alkyl, pyridine, phosphoryl) in the calixarene core was examined. The composition of the extractable solvates of americium and europium with functionalized calix[4]arenes was determined. From both alkaline and nitric acid solutions, calixarenes extract americium more efficiently than their nonmacrocyclic analogs do. The calix[4]arene with the pyridine functional group exhibits the highest selectivity, with the Am/Eu separation factor exceeding 3. Calix[4]arenebis-(methanediphosphonates) extract europium and americium from both alkaline and nitric acid solutions with similar magnitude of the cooperative effect.     

Some exact solutions to equations of transient flow with suction for a viscous fluid

Self-adjoint asymptotic solutions to the equations of flow are constructed for a viscous fluid near a permeable plane boundary.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 2, pp. 328–333, August, 1981.     

Extraction of americium and europium with functionalized thiacalix[4]arenes from alkaline solutions

The extraction of ²⁴¹Am and ¹⁵²Eu from alkaline carbonate solutions with solutions of functionalized thiacalix[4]arenes in m-nitrobenzotrifluoride was studied. The dependence of the radionuclide distribution ratios and separation factors on pH of the aqueous phase in the interval from 10 to 13.5, kind of the organic diluent, and position and electronic characteristics of functional groups in the thiacalixarene platform was examined. The composition of the extractable solvates of Am and Eu with functionalized thiacalix[4]arenes was determined by slope analysis. The hydrolytic stability of tert-butylthiacalix[4]arene in alkaline and acid solutions was evaluated. Thiacalix[4]arenes efficiently extract Am from alkaline solutions. The bromine-substituted thiacalix[4]arene exhibits the maximal selectivity, with the Am/Eu separation factor in extraction with this agent exceeding 30.     

Endotoxemia after high cutoff hemodialysis for treatment of patient with multiple myeloma can be prevented by using ultrapure dialysate: A case report

To report endotoxemia presented in a case with multiple myeloma (MM) treated by high cutoff hemodialysis (HCO‐HD) being prevented by using ultrapure dialysate. A female inpatient with MM received six times HCO‐HD (HCO 2100 dialyzer) within 3 weeks after initiation of a chemotherapy based on vincristine + epirubicin + dexamethasone protocol. Conventional dialysate was used in the first three times and then changed to ultrapure dialysate due to elevation of body temperature after HCO‐HD. Free light chains (FLC) and endotoxin levels in blood and dialysate were monitored. After six times HCO‐HD, her serum FLC λ decreased from 4689 mg/L to 492.7 mg/L, with a trend of decline of serum creatinine. The clearance, reduction ratio, and removal amount of FLC λ was 38.4 mL/min, 71.0–85.2%, and 9.06–18.02 g, respectively, in the setting of dialysate flow rate 500 mL/min, while in the setting of dialysate flow rate 200 mL/min, the removal efficacy of FLC λ was lower than the former. A rise of body temperature up to 38.5°C after treatment and endotoxemia (endotoxin levels 0.122 EU/mL) was found when using conventional dialysate (endotoxin levels 0.112–0.145 EU/mL), but not seen after changing to ultrapure dialysate. Combined with appropriate chemotherapy, HCO‐HD can effectively remove and reduce blood FLC. Attention should be paid to the endotoxemia and the rise of temperature after treatment when conventional dialysate is used, which can be prevented by using ultrapure dialysate.     

Synthesis of magnetic chelating resins functionalized with tetraethylenepentamine for adsorption of molybdate anions from aqueous solutions

Magnetic resins were synthesized through polymerization of glycidyl methacrylate (GMA) in the presence of divinylbenzene (DVB) or N,N′-methylenebisacrylamide (MBA) as hydrophobic or hydrophilic crosslinker, respectively and in presence of suspended magnetite particles. The resins containing (DVB or MBA) as crosslinker were immobilized with tetraethylenepentamine (TEP) to give the amino resins, GMA/DVB/TEP (R1-en) and GMA/MBA/TEP (R2-en), respectively. The uptake behavior of the two resins was studied towards molybdate anions and uptake capacities of 4.24 and 6.18 mmol/g [as (Mo(VI)] were obtained using (R1-en) and (R2-en). Kinetic studies showed that the adsorption followed the pseudo-second-order model pointing the influence of the textural properties of the resin on the rate of adsorption. Thermodynamic data indicated an endothermic adsorption process. The uptake of Mo(VI) and regeneration of the resins were also studied using the column method. Regeneration efficiency up to 90–96% was reached using ammonia buffer.     

Synthesis of SiC fibre with low oxygen content and high tensile strength using a polyblend precursor

SiC fibre with low oxygen content and high tensile strength was first synthesized in our laboratory. The SiC fibre was obtained by using a polyblend of polycarbosilane (PC) and hydroxy-terminated-polybutadiene (HTPB) as a precursor. It was found that PC could react with HTPB to form cross-linked polymers at temperatures around 260 ° C, so the HTPB can be used as a curing agent. Consequently, the need for oxygen to be introduced in the air-curing process is reduced and SiC fibre with low oxygen content and higher tensile strength can be made. The chemical compositions, the oxidation resistance and chemical stability of the SiC fibre were also studied here.     

Removal of water-soluble acid dyes from water environment using a novel magnetic molecularly imprinted polymer

Novel magnetic and hydrophilic molecularly imprinted polymers (mag-MIPs) were prepared by an inverse emulsion-suspension polymerization to remove water-soluble acid dyes from contaminated water with 1-(α-methyl acrylate)-3-methylimidazolium bromide (1-MA-3MI-Br) being utilized as a new functional monomer. The thermal stability, chemical structure and magnetic property of the 1-MA-3MI-Br-mag-MIPs were characterized by the thermal-gravimetric analyzer (TGA), Fourier transform infrared spectrometer (FT-IR) and vibrating sample magnetometer (VSM), respectively. Moreover, effect of concentration and pH value of water-soluble acid dye solutions was optimized. Compared with the methyl acrylic acid and 4-vinylpyridine modified mag-MIPs, the 1-MA-3MI-Br-mag-MIPs showed enhanced removal efficiency. Kinetic studies depicted that the adsorption process on 1-MA-3MI-Br-mag-MIPs followed pseudo-second-order rate mechanism. Investigation results of 5 times removal-regeneration cycles by employing the 1-MA-3MI-Br-mag-MIPs showed that the resulting material was with high stability.     

Adsorption characteristics of heavy metal ions onto a low cost biopolymeric sorbent from aqueous solutions

In this study, the adsorption conditions of Cu(II), Pb(II) and Cd(II) metal ions onto sporopollenin have been studied. The different variables effecting the sorption capacity such as pH of the solution, adsorption time, initial metal ion concentration and temperature have been investigated. Adsorption isotherms correlated well with the Freundlich type adsorption isotherm and adsorption capacities were found to be 0.0195, 0.0411 and 0.0146 mmol g(-1) for Cu(II), Pb(II) and Cd(II) metal ions, respectively. Experimental data were also evaluated to find out kinetic characteristics of the adsorption process. Adsorption processes for three target heavy metal ions were found to follow pseudo-second order type adsorption kinetics. Intraparticle diffusion was found to take part in adsorption processes but it could not be accepted as the primary rate-determining step. The mean free energies of adsorption (E) were found to be between 8 and 16 kJ mol(-1) for the metal ions studied and therefore adsorption mechanism for the adsorbent was explained as an ion-exchange process. But it was observed that chelating effect is also playing an important role in the adsorption of metal ions onto sporopollenin. Thermodynamic parameters, DeltaH degrees , DeltaS degrees and DeltaG degrees were also calculated from graphical interpretation of the experimental data. Standard heats of adsorption (DeltaH degrees ) were found to be endothermic and DeltaS degrees values were calculated to be positive for the adsorption of Cu(II), Pb(II) and Cd(II) ions onto the adsorbent. Negative DeltaG degrees values indicated that adsorption process for these three metal ions onto sporopollenin is spontaneous.     

Detection of folate binding protein with enhanced sensitivity using a functionalized quartz crystal microbalance sensor

In this report, we describe the development of a quartz crystal microbalance biosensor for detection of folate binding protein (FBP). Using a simple folate-BSA conjugate adsorbed onto a Au-coated quartz sensor, a detection limit of 30 nM was achieved. Binding of FBP to the sensor surface could be blocked at concentrations as high as 1 microM with a 100-fold excess of folic acid, indicating the specificity of the folate-FBP interaction and the absence of nonspecific binding to the functionalized surface. Moreover, capture could be achieved in the presence of blood serum, making the assay amenable to the analysis of bodily fluids. Further signal enhancement based on an anti-FBP antibody and protein-A-coated gold nanosphere sandwich assay extended the detection limit to 50 pM (approximately 3 orders-of-magnitude improvement). Given the overexpression of FBP in certain malignancies and inflammatory disorders, we expect the methodology described here to be useful to detect FBP as a possible biomarker for disease diagnosis.     

Removal of lead from aqueous solutions using an immobilized biomaterial derived from a plant biomass

Because of the severity of heavy metal contamination and potential adverse health impact on the public, a tremendous effort has taken place to purify waters containing toxic metal ions. Traditional methods which have been employed prove to be costly and prohibitive for low level waste remediation. Biosorption is presented as an alternative to traditional physicochemical means for removing toxic metals from ground and wastewaters. Most recently, plant based biomaterials have been of interest. The bark of Hemidesmus indicus, an extensively available plant biomass commonly called as Indian sarsaparilla was used as biomaterial for removal of lead from aqueous streams. Batch experiments were carried out with immobilized biomass of H. indicus (IPBFIX) to optimize the experimental parameters like effect of contact time, initial metal concentration, initial IPBFIX concentration and co-metal ion effect on biosorption of lead from contaminated waters. Column experiments were performed under flow conditions for regeneration and recycle efficiency of IPBFIX and was found to be effective for three cycles. Elution experiments were carried out to remove lead ions from loaded IPBFIX and 100% elution was achieved with a 0.1M HNO(3) solution. The effectiveness of the IPBFIX for biosorption of lead ions was demonstrated using the wastewater samples emanating from a non-ferrous metal industry and the results are presented in this paper. The results from these studies will be useful for a novel phytofiltration technology to remove and recover lead from wastewaters and this can also be well adapted for secondary treatment or polishing of wastewaters. An attempt has been made to remove lead from the lead polluted waters (both ground and surface) from an industrially contaminated sites.     

一种低成本高性能的巡逻保安机器人

为满足在办公室、仓库等建筑内巡逻的要求,研制了一种低成本、高性能的巡逻保安机器人.其传感器系统采用分层模糊理论,能够在比较复杂的情况下完成自主导航和障碍避碰等任务.火灾探测系统采用神经网络和灰色预测理论,提高了报警的灵敏度,减少了误报警,缩短了报警时间.无线通讯的方式更适合于网络监控和远程操纵.实验证明,该巡逻保安机器人具有低成本、高性能的特点,具有较高的性价比,适合办公室、仓库、厂房等环境的巡逻与监控.     

Most unstable waves of a stagnant planar liquid film blown by a high speed viscous gas with a Blasius velocity profile

Summary The linear most unstable waves generated on the surface of a stagnant planar liquid (gasoline) film with infinite thickness, blown by a high speed viscous gas (air) with a Blasius velocity profile, are computed and analyzed. The free-stream velocity of the gas ranges from 30 m/s to 50 m/s, which is typical of high speed atomization problems. The Reynolds number based on the local thickness of the boundarylayer lies between 200 and 2500. The numerical computation shows that the dimensional wavelength of the most unstable wave is a power functions of the boundary-layer thickness (or Reynolds number) with a power close to 3/4, while the growth rate is inversely proportional to the boundary-layer thickness. When reducing the boundary-layer thickness, the visocus results approach the inviscid results. This result shows that, under the present parameter range, the gas viscosity would have a secondary role on the atomization speed and important influence on the droplet size.     

Reduction of Pu(IV) and Np(VI) with hydroxylamine in solutions of low acidity with high uranium content

Decomposition of hydroxylamine in HNO₃ solutions containing 350 to 920 g l^?1 U(VI) was studied. In the absence of fission and corrosion products (Zr, Pd, Tc, Mo, Fe, etc.), hydroxylamine is stable for no less than 6 h at [HNO₃] < 1 M and 60°C. In the presence of these products, the stability of hydroxylamine appreciably decreases. The reduction of Pu(IV) and Np(VI) with hydroxylamine in aqueous 0.33 and 0.5 M HNO₃ solutions containing 850 g l^?1 U(VI) and fission and corrosion products at 60°C was studied. Np(VI) is rapidly reduced to Np(V), after which Np(V) is partially reduced to Np(IV). The rate of the latter reaction in such solutions is considerably higher than the rate of the Np(V) reduction with hydroxylamine in HNO₃ solutions without U(VI). At [HNO₃] = 0.33 M, the use of hydroxylamine results in the conversion of Pu to Pu(III) and of Np to a Np(IV,V) mixture, whereas at [HNO₃] = 0.5 M the final products are Pu(IV) and Np(V).     

High fidelity multidisciplinary design optimization of a wing using the interaction of low and high fidelity models

This paper presents an efficient metamodel building technique for solving collaborative optimization (CO) based on high fidelity models. The proposed method is based on a metamodeling concept, that is designed to simultaneously utilize computationally efficient (low fidelity) and expensive (high fidelity) models in an optimization process. A distinctive feature of the method is the utilization of interaction between low and high fidelity models in the construction of high quality metamodels both at the discipline level and system level of the CO. The low fidelity model is tuned in such a way that it approaches the same level of accuracy as the high fidelity model; but at the same time remains computational inexpensive. In this process, the tuned low fidelity models are used in the discipline level optimization process. In the system level, to handle the computational cost of the equality constraints in CO, model management strategy along with metamodeling technique are used. To determine the fidelity of metamodels, the predictive estimation of model fidelity method is applied. The developed method is demonstrated on a 2D Airfoil design problem, involving tightly coupled high fidelity structural and aerodynamic models. The results obtained show that the proposed method significantly reduces computational cost, and improves the convergence rate for solving the multidisciplinary optimization problem based on high fidelity models.     

Polarization of 'water-skies' above arctic open waters: how polynyas in the ice-cover can be visually detected from a distance

The foggy sky above a white ice-cover and a dark water surface (permanent polynya or temporary lead) is white and dark gray, phenomena called the 'ice-sky' and the 'water-sky,' respectively. Captains of icebreaker ships used to search for not-directly-visible open waters remotely on the basis of the water sky. Animals depending on open waters in the Arctic region may also detect not-directly-visible waters from a distance by means of the water sky. Since the polarization of ice-skies and water-skies has not, to our knowledge, been studied before, we measured the polarization patterns of water-skies above polynyas in the arctic ice-cover during the Beringia 2005 Swedish polar research expedition to the North Pole region. We show that there are statistically significant differences in the angle of polarization between the water-sky and the ice-sky. This polarization phenomenon could help biological and man-made sensors to detect open waters not directly visible from a distance. However, the threshold of polarization-based detection would be rather low, because the degree of linear polarization of light radiated by water-skies and ice-skies is not higher than 10%.     

Separation of 2,6-dimethylnaphthalene from a mixture of its isomers using lithium-incorporated zeolite Y synthesized by rapid crystallization method

Lithium-incorporated zeolite Ys (Li-NaYs) were directly synthesized under a hydrothermal condition from a gel mixture of Li₂O·Na₂O·SiO₂·Al₂O₃·H₂O. It was confirmed by XRD, NMR and elementary analysis, that lithium ions could be introduced onto the ion sites of zeolite Y during the course of crystallization. Usage of lithium citrate as the lithium source is the indispensable factor to achieve the synthesis. In adsorption of mixtures of 2,6-dimethylnaphthalene and its isomers, Li-NaYs exhibited greater adsorptive capacities and higher adsorption selectivities to 2,6-dimethyl naphthalene than NaY. Direct hydrothermal synthesis of Li-incorporated zeolite Y prevents the blockage of pore openings and/or channels during lithium ion-exchange. Furthermore, the difference in adsorptive properties between Li-NaY and Li ion-exchanged NaY is due to Li ions being introduced onto the S₁ ion sites, which can hardly be ion-exchanged, during the hydrothermal synthesis.     

Preparation of high performance (Bi,Pb)-2223 superconductor using a sol–gel synthesized amorphous precursor through controlled gelation

A controlled gelation method through an acrylate route is identified for the synthesis of high quality precursors for the production of bulk (Bi,Pb)-2223 superconductors. The method overcomes the problem of undesirable precipitation of crystallites during gelation by controlling the vapour loss from the sol and the temperature and leads to an amorphous gel which on subsequent processing results in a highly reactive and homogenous precursor. (Bi,Pb)-2223 superconductors prepared from the precursor have shown highly enhanced properties with respect to final phase purity, sintered density, microstructure and critical current density compared to those prepared from conventional solid state precursors.