Reverse logistics network design and planning utilizing conditional value at risk

Nowadays, due to some social, legal, and economical reasons, dealing with reverse supply chain is an unavoidable issue in many industries. Besides, regarding real-world volatile parameters, lead us to use stochastic optimization techniques. In location–allocation type of problems (such as the presented design and planning one), two-stage stochastic optimization techniques are the most appropriate and popular approaches. Nevertheless, traditional two-stage stochastic programming is risk neutral, which considers the expectation of random variables in its objective function. In this paper, a risk-averse two-stage stochastic programming approach is considered in order to design and planning a reverse supply chain network. We specify the conditional value at risk (CVaR) as a risk evaluator, which is a linear, convex, and mathematically well-behaved type of risk measure. We first consider return amounts and prices of second products as two stochastic parameters. Then, the optimum point is achieved in a two-stage stochastic structure regarding a mean-risk (mean-CVaR) objective function. Appropriate numerical examples are designed, and solved in order to compare the classical versus the proposed approach. We comprehensively discuss about the effectiveness of incorporating a risk measure in a two-stage stochastic model. The results prove the capabilities and acceptability of the developed risk-averse approach and the affects of risk parameters in the model behavior.     

A study of the thermal properties of single jersey fabrics of cotton, bamboo and cotton/bamboo blended-yarn vis-a-vis bamboo fibre presence and yarn count

In this study, the thermal properties of 100% cotton, 50/50 cotton/bamboo and 100% bamboo single jersey fabrics with differing yarn linear density are evaluated and analysed. The linear densities of the yarns composing the fabrics are 20^s, 25^s, 30^s Ne_c and the twist level in the yarns is kept the same. An increasing the presence of bamboo fibre in the fabric causes a reduction in fabric thickness and GSM for all linear densities of yarn. Air permeability and water-vapour permeability also increase with increase in bamboo fibre content while both thermal conductivity and thermal resistance show a decreasing trend. As the constituent yarn gets finer, fabric air and water-vapour permeability both increase in value while the thermal conductivity falls.     

Efficient synthesis of mono- and bis-arylated ethylenedioxy thiophene-based functional π-conjugated molecules via clay-supported palladium-catalysed direct arylation reactions

An active Pd catalyst was prepared by the modification of montmorillonite clay. The catalyst was found to be effective for the synthesis of ethylenedioxy thiophene-based π-conjugated molecules. The reaction proceeded through clay-supported Pd-catalysed direct C–H bond activation (arylation) mechanism. Preparation, characterization and application of the catalysts are reported. The products were analysed with LCMS, and comparison with reported spectral data (FT-IR, ¹H NMR). Reusability of clay-supported palladium catalyst towards direct arylation reaction was tested for three reaction cycles without a significant loss of catalytic activity.

     

The Attenuating Effect of Beta-Carotene on Streptozotocin Induced Diabetic Vascular Dementia Symptoms in Rats

This study investigated the ameliorative effects of beta-carotene (BC) on diabetes-associated vascular dementia and its action against biomolecule oxidation. The diabetic vascular dementia (VaD) was induced by administration of nicotinamide (NA; 50 mg/kg; i.p.) and streptozotocin (STZ; 50 mg/kg; i.p.). The test compound, BC (50 and 100 mg/kg; p.o.), and the reference compound, donepezil (DP) (1 mg/kg; p.o.), were administered for 15 consecutive days. Changes in learning and memory were assessed by escape latency time (ELT) and times spent in target quadrant (TSTQ) in the Morris water maze (MWM) test. The changes in neurotransmitter, i.e., acetylcholinesterase (AChE) and oxidative stress markers, i.e., thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH), were estimated in hippocampal tissue of the rat brain. The administration of STZ caused significant deterioration of cognitive function (decreased ELT and raised the TSTQ) as compared to the normal group. Treatment with BC and DP diminished the increased AChE activity, TBARS level and decreased GSH level caused by STZ. Thus, BC ameliorates the diabetic vascular complications in VaD due to its potential anticholinergic, antioxidative and free radical scavenging actions.     

Notched tensile strength for long- and short-fiber reinforced polyamide

The point stress criterion and the average stress criterion are applied for evaluating the notched tensile strength of injection-moulded plates with machined and moulded-in notches. Use is made of a characteristic length which is found to be geometry and material dependent.     

Synthesis,characterization, electrochemical and photophysical properties of bimetallic complexes of rhenium(I) and osmium(II)

Monometallic and bimetallic diimine complexes of rhenium(I) and osmium(II), [(CO)₃(bpy)Re(4,4′-bpy)](PF₆) I, [(CO)₃(bpy)Re(4,4′-bpy)Re(bpy)(CO)₃](PF₆)₂II, [Cl(bpy)₂Os(4,4′-bpy)](PF₆) III and [Cl(bpy)₂Os(4,4′-bpy)Os(bpy)₂Cl](PF₆)₂IV, and a new heterobimetallic complex of rhenium(I) and osmium(II) [(CO)₃(bpy)Re(4,4′-bpy)Os(bpy)Cl](PF₆)₂V (bpy = 2,2′-bipyridine; 4,4′-bpy = 4,4′-bipyridine) have been synthesized and characterized by various spectral techniques. The photophysical properties of all the complexes have been studied and a comparison is made between the heterobimetallic and corresponding monometallic and homobimetallic complexes. Emission and transient absorption spectral studies reveal that excited state energy transfer from the rhenium(I) chromophore (∗Re) to osmium(II) takes place. The energy transfer rate constant is found to be 8.7 × 10⁷ s⁻¹.     

X-ray photoelectron spectroscopic investigations on cubic BaTiO3, BaTi0.9Fe0.1O3 and Ba0.9Nd0.1TiO3 systems

X-ray photoelectron spectroscopic (XPS) studies were carried out on wet-chemically synthesized cubic BaTiO₃, Ba_0.9Nd_0.1TiO₃ and BaTi_0.9Fe_0.1O_3−δ powders. The compounds were prepared by hydrothermal and gel to crystallite conversion technique; and phases formed readily at 420 K. The phase purity of the powders was confirmed from X-ray diffractometry. Chemical state and chemical environment of the constituent elements in the compositions were examined by XPS. Ba²⁺ was found to exist in two different chemical environments in these titanates. The Ti 2p_3/2 photoelectron peak in BaTi_0.9Fe_0.1O_3−δ was found to be broadened after Fe³⁺ substitution. Any resolvable broadening was not observed distinctly in the Ti 2p peak for Ba_0.9Nd_0.1TiO₃, unsintered BaTiO₃ and BaTiO₃ annealed in hydrogen (8% H₂ + Ar) at 1000 K. The prevalence of mixed-valent titanium and iron in BaTi_0.9Fe_0.1O_3−δ composition was evident from the XPS results and was further supported by the enhanced electrical conductivity at 298-550 K for BaTi_0.9Fe_0.1O_3−δ in comparison to BaTiO₃ and Ba_0.9Nd_0.1TiO₃. Hydroxyl incorporation was facilitated by substituting Nd³⁺ in Ba-sublattice. The presence of hydroxyls was observed from the broadening of the O 1s peak in XPS studies of the compounds.     

Symmetry and <Emphasis Type="Italic">p</Emphasis>-Stability

A symmetry of a game is a permutation of the player set and their strategy sets that leaves the payoff functions invariant. In this paper we introduce and discuss two relatively mild symmetry properties for set-valued solution concepts (that are equivalent when the solution concepts are single-valued) and show using examples that stable sets satisfy neither version. These examples also show that for every integer q, there exists a game with an equilibrium component of index q.Received February 2002/Revised November 2003Supported by an EPSRC doctoral grant.     

Eco-friendly decoration of graphene oxide with green synthesized silver nanoparticles: cytotoxic activity

Research on Chemical Intermediates - The aim of the present study was to focus on the green synthesis of silver nanoparticles (AgNPs) using the aqueous extract of dried jujube fruit and the...