An Adaptive Biased Single-Stage CMOS Operational Amplifier with a Novel Rail-to-Rail Constant-<Emphasis Type="Italic">g</Emphasis><Subscript><Emphasis Type="Italic">m</Emphasis></Subscript> Input Stage

Using rail-to-rail (R-R) swing analog circuits has become almost mandatory in the design of low supply voltage circuits. In this paper, a new architecture for constant-g_m rail-to-rail input stages is presented. The design features a less than 5% deviation in g_m over the entire range of the input common-mode voltage. Furthermore, a new structure for folded cascode amplifier based on the use of a floating current source is presented. By employing these techniques, a low-power operational amplifier (op-amp) with 100 MHz unity-gain bandwidth, 106 dB gain, 60^∘ phase margin, 2.65 V swing, and 6.4 nV/✓Hz input-referred noise with rail-to-rail input common-mode range is realized in a 0.8 μ m CMOS technology. This amplifier dissipates 10 mW from a 3 V power supply.     

Extraction of essential oils from Bunium persicum Boiss. using superheated water

A comparative study of superheated water extraction (SWE) with two conventional volatile isolation methods including hydrodistillation and Soxhlet extraction was performed on Bunium persicum Boiss. Influence of operating conditions such as temperatures from 100 to 150 °C, mean particle size from 0.5 to 1.0 mm and flow rates from 2 to 4 mL/min on the extraction process was investigated. The experiments were carried out using a laboratory-built apparatus. Separation and identification of the components were carried out by GC-FID and GC/MS. The optimum extraction efficiency for SWE was determined at 125 °C, 4 mL/min and 0.5 mm. At these operating conditions, the extraction efficiency was lower than hydrodistillation and Soxhlet extraction methods, but SWE was quicker and with respect to the valuable oxygenated components, it was more selective.     

Elaboration and dielectric study of ferroelectric or relaxor ceramics in the ternary system BaTiO3-NaNbO3-BaSnO3

The present work reports the elaboration and physical investigation of new compounds of the following composition Ba_1−xNa_x(Ti_1−ySn_y)_1−xNb_xO₃ (BTSnNxy). The studied ternary system presents some continuous solid solutions between the next 3 phases: the NaNbO₃ antiferroelectric phase that becomes easily ferroelectric at low rate substitutions, the BaTiO₃ ferroelectric phase and the paraelectric stannate phase BaSnO₃. Two different dielectric behaviors can be observed once some substitutions are made either in A or B sites of an ABO₃ perovskite. These substitutions modify the dielectric properties of the material. The introduction of Sn⁴⁺ and Ti⁴⁺ cations in the B site favors, respectively, a decrease of the transition temperature and an increase in the value of the real dielectric permittivity. The transition temperature should be modulated by varying the rate of cationic substitution. Some relaxor materials can be obtained at a temperature around room temperature.     

Synthesis of nanostructured BSCF by oxalate co-precipitation – As potential cathode material for solid oxide fuels cells

Ba_xSr_1−xCo_yFe_1−yO₃ (BSCF) cathode material for solid oxide fuel cells (SOFC) was synthesized in nanocrystalline form by a novel chemical alloying approach. Thermodynamic modeling has been performed using Medusa software for obtaining the optimum conditions for the fabrication of a precursor with the desired composition. Precursor powder was then calcined and annealed to produce the final mixed oxide BSCF composition. The thermal properties, phase constituents, microstructure and elemental analysis of the samples were characterized by TGA, XRD, SEM and EDS techniques respectively. Spark Plasma Sintering (SPS) has been used at 1080 °C and under 50 MPa pressure to obtain the pellets of BSCF with preserved nanostructure and rather high compaction density for electrical conductivity measurements. The results show that the powders have cubic perovskite-type structure with a high homogeneity. Finer resultant powder, compared to earlier reports, and SPS sintered BSCF with nanosized grains exhibited a significantly higher electrical conductivity up to 900 °C. Specific conductivity values have been measured in air and N₂ and the maximum of 63 S cm⁻¹ at 430 °C in air and 25 S cm⁻¹ at 375 °C in N₂ correspondingly show twice as much as conventional BSCF implying a high pledge for nano-BSCF as cathode material in intermediate-temperature SOFC. This is due to the lower interfacial resistance of preserved nanograins by the use of SPS sintering. Presented co-precipitation method is easy to handle and has a high promise to synthesize BSCF at large-scale for IT-SOFCs.     

Reducing power of Eucalyptus oleosa leaf extracts and green synthesis of gold nanoparticles using the extract

Assay of the antioxidant content and reducing power of the plant extracts is a crucial point in phytochemistry, the food industry, and nutrition. On the other hand, green synthesis of noble metal nanoparticles, such as gold by the aid of plant extract is dependent on the reducing power and antioxidant content of the extract. In this work, cyclic voltammetry was utilized as a facile technique for screening antioxidant properties and estimating the reducing power of the medicinal plant extracts. The effect of different extraction conditions on the reducing power of the aqueous extract was also determined through the cyclic voltammetry technique. The extract of Eucalyptus oleosa leaves obtained at optimum conditions of this study (with maximum reducing power based on cyclic voltammetry assay) was utilized for the green synthesis of gold nanoparticles. Furthermore, the kinetic of the synthesis reaction was investigated by the aid of ultraviolet-visible spectrophotometry based on surface Plasmon resonance for gold nanoparticles at 552 nm. Meanwhile, the synthesized gold nanoparticles were characterized by the transmission electron microscopy technique.     

Developing an integrated inventory management model for multi-item multi-echelon supply chain

As the industrial environment becomes more competitive, supply chain management (SCM) has attained growing attention from practical and academic societies as a crucial discipline. Among the involved decisions in the field of SCM, integrated inventory management is addressed in this paper. In this regards, this paper proposes an integrated inventory management model within a multi-item, multi-echelon supply chain (SC). The considered SC comprises multiple agents in upper layers supplying those of lower layer to enhance flexibility of the SC. Furthermore, three inventory models are developed with respect to different layers of SC in an integrated manner, seeking to optimize total cost of the whole SC. Due to nonlinear structure of the proposed model; high level of computational complexity is resulted. To cope with the complexity of proposed model, a differential evolution algorithm is adopted. Conducted numerical results indicate validity of the developed algorithm.     

Investigating the influence of gamma ray energies and steel fiber on attenuation properties of reactive powder concrete

A smoothing algorithm for energy spectrum based on differential nonlinearity (DNL) error elimination with total counts conservation for high-energy particle detector systems is presented.It is physics based and is only determined by the DNL error of analog-to-digital converter device itself.From the experimental results,this algorithm slightly improves both noise performance and energy resolution,while greatly reduces the testing errors by almost a half compared to their original values.In addition,the reduced-x2 statistic for evaluating the Gaussian fitting goodness is significantly reduced by almost two orders after smoothing.As a typical verification example,this algorithm is successfully applied in the ground calibration of the Low Energy X-ray Instrument onboard the Hard X-ray Modulation Telescope (HXMT-LE) satellite,lending it a powerful,nondestructive and low-cost tool for both calibration and data processing for high-energy particle detector systems.     

3D Modeling of the Elastic-Plastic Behavior of Thin Aeronautical Adhesive Films Suited for a Wide Range of Tensile/Compression-Shear Loads

Adhesive bonding is an interesting structural assembling technique for weight saving in modern commercial aircraft, in which the use of composites materials is increasing. In order to meet both optimization and respect of safety conception constraints, the development of accurate numerical strategies is required. Thus, improvement in the experimental characterization and in the design of reliable numerical tools for bonded assemblies is necessary. This paper presents the characterization of the elastic-plastic behaviour of four aeronautical adhesive films, consisting of two epoxy-based resins supported by two types of carrier. The characterization over a wide range of monotonic proportional tensile-shear loads is performed using a modified Arcan test device designed to strongly limit the influence of edge effects. Moreover, to obtain an accurate definition of the initial elastic limit of the adhesives, further experimental tests have been performed using a pressure vessel especially designed to study the influence of the hydrostatic stress. Inverse identification techniques using finite element analysis have been used to identify the material parameters of an elastic-plastic model based on the experimental results (the load-displacement curves). Results underline the potential of such a model to represent the non-linear behaviour of ductile adhesives under tensile/compression-shear proportional monotonic loads.     

An artificial intelligence approach for fuzzy possibilistic-stochastic multi-objective logistics network design

In this paper, a logistics network is investigated which includes multi-suppliers, collection centers, transfer stations, treatment stations, and products. For this purpose, a multi-objective mathematical programming model is proposed that minimizes the total costs including the fixed costs for opening facilities and transportation costs between facilities, minimizes the distance between each waste-generating facilities and transfer stations, maximizing the distance between treatment and disposal stations and customer zones, and maximizes the sum of the reliability of coverage for the potential facilities which will be open. In order to make the results of this paper more realistic, a case study in the iron and steel industry has been investigated. Besides, a new solution approach is proposed by combining fuzzy possibilistic programming, stochastic programming, and fuzzy multi-objective programming. Moreover, an imperialist competitive algorithm is proposed to obtain near optimal solution in comparison with other evolutionary algorithms. Finally, computational experiments are provided to demonstrate the applicability and suitability of the proposed model and solution approaches.