Static magnetic properties of Co and Ru substituted Ba-Sr ferrite

M-type hexagonal ferrite powders, Ba_0.5Sr_0.5Co_xRu_xFe_(12−2x)O₁₉ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2) have been synthesized by conventional ceramic method. Magnetic properties have been investigated as a function of substitution of Co and Ru ions at applied external field of 10 kOe. XRD and SEM revealed hexagonal structure for these ferrites. The Co and Ru ions substitution cause increase in saturation magnetization and rapid decrease in magnetocrystalline anisotropy at lower substitution. The magnetic parameters variation has been explained by taking into account preferential site occupancy of sublattice sites by substituted ions. Curie temperature decreases with substitution due to weakening of superexchange interaction. The obtained hysteresis parameters suggest that the proposed materials cannot be used for recording applications.     

Lumped Approach to a Multi-Period–Multi-Reservoir Cyclic Storage System Optimization

Cyclic storage system (CSS) refers to the joint development and operation of surface impoundment and subsurface subsystems with natural and physical interaction and a prespecified operating rule which manages the inter-relation between different components of the system. This paper presents a lumped modeling approach to a generalized large scale cyclic storage system. The model is capable to optimally design and operate a cyclic system in an irrigable area. The excitation units with pronounced impact and a complexity of the semi-distributed model are replaced with approximated lumped functions, while maintaining a desirable level of accuracy in the system’s performance in a long-term planning horizon. The proposed model has a MINLP structure, which is solved using powerful well-known LINGO solver. Design capacities of different components of the system and the associated operating rules parameters are considered as decision variables that minimize total cost of operating costs over the planning horizon. Extensive simulation runs show that the derived operating rules perform quite satisfactory with non-significant deficits over the entire horizon.     

Trastuzumab‐conjugated nanoparticles composed of poly(butylene adipate‐co ‐butylene terephthalate) prepared by electrospraying technique for targeted delivery of docetaxel

Human epidermal growth factor receptor 2 (HER‐2) is overexpressed in 20–30% of human breast cancers, associated with poor prognosis and tumour aggression. The aim of this study was the production of trastuzumab‐targeted Ecoflex nanoparticles (NPs) loaded with docetaxel and in vitro evaluation of their cytotoxicity and cellular uptake. The NPs were manufactured by electrospraying and characterised regarding size, zeta potential, drug loading, and release behaviour. Then their cytotoxicity was evaluated by MTT assay against an HER‐2‐positive cell line, BT‐474, and an HER‐2‐negative cell line, MDA‐MB‐468. The cellular uptake was studied by flow cytometry and fluorescent microscope. The particle size of NPs was in an appropriate range, with relatively high drug entrapment and acceptable release efficiency. The results showed no cytotoxicity for the polymer, but the significant increment of cytotoxicity was observed by treatment with docetaxel‐loaded NPs in both HER‐2‐positive and HER‐2‐negative cell lines, in comparison with the free drug. The trastuzumab‐targeted NPs also significantly enhanced cytotoxicity against BT‐474 cells, compared with non‐targeted NPs.Inspec keywords: cancer, proteins, biomedical materials, nanofabrication, drug delivery systems, cellular biophysics, biological organs, nanomedicine, toxicology, tumours, nanoparticles, biomedical optical imaging, fluorescence, particle sizeOther keywords: human breast cancers, tumour aggression, trastuzumab‐targeted Ecoflex nanoparticles, cellular uptake, zeta potential drug loading, HER‐2‐positive cell line, HER‐2‐negative cell line, MDA‐MB‐468, particle size, trastuzumab‐conjugated nanoparticles, electrospraying technique, human epidermal growth factor receptor, cytotoxicity, nontargeted nanoparticles, butylene adipate‐co‐butylene terephthalate, trastuzumab‐targeted NP, docetaxel‐loaded NP     

A Novel Cu–GNPs Nanocomposite with Improved Thermal and Mechanical Properties

Classical powder metallurgy followed by either hot isostatic pressing(HIPing) or repressing–annealing process was used to produce Cu–graphene nanoplatelets(GNPs) nanocomposites in this work. A wet mixing method was used to disperse the graphene within the matrix. The results show that a uniform dispersion of GNPs at low graphene contents could be achieved, whereas agglomeration of graphene was revealed at higher graphene contents. Density evaluations showed that the relative density of pure copper and copper composites increased by using the post-processing techniques.However, it should be noticed that the efficiency of HIPing was remarkably higher than repressing–annealing process, and through the HIPing, fully dense samples were achieved. The Vickers hardness results showed that the reconsolidation steps can improve the mechanical strength of the specimens up to 50% owing to the progressive porosity elimination after reconsolidation. The thermal conductivity results of pure copper and composites at high temperatures showed that the postprocessing techniques could enhance the conductivity of materials significantly.     

Cellulose fabric with enhanced water absorbance and permeability using microwave radiation: modeling and optimization by RSM

Body temperature control is one of the most interesting fields in the smart sportswear. Increasing the available hydrophilic sites on the fabric surface is one of the proposed methods for better thermal regulation. In this article, the cellulose fabric’s moisture absorbance capacity was increased by introducing carboxylate groups on the cellulosic fabric using microwave radiation. Response surface methodology was used to optimize the process conditions. Stoichiometric ratio, microwave power, and duration were taken as independent variables; moisture regain and softness were selected as dependent variables. Results show that modification with 1:1 stoichiometric ratio of the reactant to anhydroglucose unit using 1049 W power for 6 min is the optimum condition for obtaining cellulose fabric with highest hydrophilicity and softness. Water vapor permeability as well as static and dynamic contact angle show that the modified fabric is more hydrophilic and transfers vapor better than unmodified cellulose fabric. Also, tensile test shows that this treatment does not affect the mechanical properties of fabrics. Fourier transform infrared spectroscopy and scanning electron microscope were used for fabric characterization.     

Differential photo-voltage spectroscopy for characterizing epitaxial multilayered and quantum well structures

An improved photo-voltage spectroscopy (PVS) technique, capable of accurately characterizing multilayered and quantum well structures, is presented. The technique is developed by noise reduction and differentiation of the photovoltage signal which improves the accuracy and sensitivity of the standard photo-voltage spectroscopy dramatically. The resulting differential-photo-voltage spectroscopy is capable of measuring the energy gap (E_g) and hence the composition, of ternary and quaternary compounds in multilayered structures at room temperature, with a substantially higher degree of confidence than the standard PVS technique. Several structures have been examined successfully. Two representative AlGaAs/GaAs structures are reported here to establish the capabilities of this technique. These structures were found to provide values for E_g and Al mole fraction, in excellent agreement with both the targeted values based on reflective high-energy electron diffraction oscillations during molecular beam epitaxial growth, and the measured values from variable angle ellipsometry. Numerous exciton transitions from quantum wells are clearly resolved and shown to be in excellent agreement with the theoretically predicted ones.     

Picomolar detection of insulin at renewable nickel powder-doped carbon composite electrode

A sol-gel technique was used for fabrication of a renewable carbon composite electrode (CCE) modified with nickel powder. This modified electrode shows excellent catalytic activity for the oxidation of insulin in alkaline solutions. The nickel powder was then oxidized to form a nickel oxide film electrode, which was used as an amperometric detector for hydrodynamic amperometry and flow injection analysis of insulin. It was found that the calibration curve was linear up to 30 microM with a detection limit of 40 pM under the optimized conditions for hydrodynamic amperometry using a rotating disk modified CCE. Flow injection amperometric determination of insulin at this modified electrode yielded a calibration curve with the following characteristics; linear dynamic range of 15-1000 pM, sensitivity of 8659.23 pA pM-1 cm-2, and detection limit of 2 pM. This electrode shows many advantages as an insulin sensor such as simple preparation method without using any specific electron-transfer mediator or specific reagent, high sensitivity, excellent catalytic activity, short response time, long-term stability, and remarkable antifouling property toward insulin and its oxidation product. Sensitivity, detection limit, and antifouling properties of this insulin sensor are better than all of the reports in the literature. Additionally, it is promising for monitoring insulin in chromatographic effluents.     

Seismic retrofitting of old‐type RC columns with different lap splices by NSM GFRP and steel bars

This paper describes the experimental results from flexural strengthening of old‐type concrete columns reinforced with plain bars and different lap splices constructed before the 1970s. Nine half‐scale column specimens were tested under combined constant axial and quasi‐static cyclic lateral loads. The specimens included 3 control specimens and 6 other specimens strengthened via near surface mounted technique with glass‐fiber reinforced plastic and steel bars. The effect of different longitudinal bar lap splices of columns and the type of strengthening materials were also investigated. The results indicated that the proposed strengthening method significantly increases the flexural strength and improves the seismic parameters, for example, energy dissipation and hysteresis damping. The specimens strengthened with steel bars presented higher strength, ductility, and hysteresis damping compared to those strengthened with glass‐fiber reinforced plastic bars. The formation of struts at the control specimen with hooked lap splices caused severe damages at the spliced region; if appropriate wrapping is done at the column end, these damages will be constrained. Using steel bars as near surface mounted reinforcement, utilizing epoxy resins as bonding agent, and installing fiber‐reinforced polymer wrapping at the end of column will all make a more effective strengthening method. Finally, an analytical work was presented for predicting the capacity of test specimens, and the comparison between experimental results and theoretical predictions showed a good agreement.