Solution approaches for highly primal- and dual-degenerate all-integer programming problems

In this paper, we discuss solution approaches to the important but difficult class of all-integer programming problems that are highly primal and dual-degenerate. In particular, we note our success with an “objective function cut” in this regard, and exhibit a computational comparison with other cutting plane techniques.     

A Surrogate cutting plane algorithm for all-integer programming

In this paper we present an all-integer cutting plane technique called the surrogate cutting plane algorithm (SCPA), for solving the all-integer (otherwise linear) programming problem. We develop and solve a smaller surrogate problem based on the solution of the LP relaxation, and thereby speed convergence to the optimal solution of the original problem. We exhibit the operation of the SCPA on three small example problems, and discuss computational results on a set of standard test problems.     

Multi-walled carbon nanotubes (MWCNTs) and room temperature ionic liquids (RTILs) carbon paste Er(III) sensor based on a new derivative of dansyl chloride

Solution studies showed the strong interaction of [5-(dimethylamino) naphthalene-1-sulfonyl 4-phenylsemicarbazide] (NSP) with Er(III) ions. NSP was used as a sensing material during construction of carbon paste Er(III) sensors. The electrodes were modified with 1-n-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF₄, as room temperature ionic liquid (RTIL) and multi-walled carbon nanotube (MWCNT). Potentiometric sensors constructed with [bmim]BF₄ and MWCNTs show better sensitivity, selectivity, response time, and response stability compared to Er(III) carbon paste sensors. The best performance for the modified sensor was obtained with an electrode composition of 20% [bmim]BF₄, 20% NSP, 45% graphite powder and 15% MWCNT. This particular sensor formulation exhibits a Nernstian response (19.8 ± 0.3 mV decade⁻¹) toward Er(III) ions in the range of 1.0 × 10⁻⁷ to 1.0 × 10⁻¹ mol L⁻¹ with a detection limit of 5.0 × 10⁻⁸ mol L⁻¹. The proposed modified Er(III) sensor can be used over the pH range from 3.5 to 9.0.     

Curcumin Attenuates Environment-Derived Osteoarthritis by Sox9/NF-kB Signaling Axis

Inflammation has a fundamental impact on the pathophysiology of osteoarthritis (OA), a common form of degenerative arthritis. It has previously been established that curcumin, a component of turmeric (Curcuma longa), has anti-inflammatory properties. This research evaluates the potentials of curcumin on the pathophysiology of OA in vitro. To explore the anti-inflammatory efficacy of curcumin in an inflamed joint, an osteoarthritic environment (OA-EN) model consisting of fibroblasts, T-lymphocytes, 3D-chondrocytes is constructed and co-incubated with TNF-α, antisense oligonucleotides targeting NF-kB (ASO-NF-kB), or an IkB-kinase (IKK) inhibitor (BMS-345541). Our results show that OA-EN, similar to TNF-α, suppresses chondrocyte viability, which is accompanied by a significant decrease in cartilage-specific proteins (collagen II, CSPG, Sox9) and an increase in NF-kB-driven gene proteins participating in inflammation, apoptosis, and breakdown (NF-kB, MMP-9, Cox-2, Caspase-3). Conversely, similar to knockdown of NF-kB at the mRNA level or at the IKK level, curcumin suppresses NF-kB activation, NF-kB-promotes gene proteins derived from the OA-EN, and stimulates collagen II, CSPG, and Sox9 expression. Furthermore, co-immunoprecipitation assay shows that curcumin reduces OA-EN-mediated inflammation and chondrocyte apoptosis, with concomitant chondroprotective effects, due to modulation of Sox-9/NF-kB signaling axis. Finally, curcumin selectively hinders the interaction of p-NF-kB-p65 directly with DNA—this association is disrupted through DTT. These results suggest that curcumin suppresses inflammation in OA-EN via modulating NF-kB-Sox9 coupling and is essential for maintaining homeostasis in OA by balancing chondrocyte survival and inflammatory responses. This may contribute to the alternative treatment of OA with respect to the efficacy of curcumin.     

Evaluation of Four Tree Algorithms in Predicting and Investigating the Changes in Aquifer Depth

One of the key elements in improved management and better planning for aquifer maintenance is the ability to predict changes in aquifer depth. In order to forecast changes in aquifer depth in Qazvin plain, four methods, including Classification and Regression Tree (CART), Reduced Error Pruning Trees (RepTree), M5-Pruned (M5P), and M5Rule, were used in this work. The absolute mean error (MAE) and coefficient of determination (R2) data show that the CART algorithm performs better than other algorithms at forecasting changes in aquifer depth. The CART algorithm's prediction findings showed that the aquifer's behavior in the two seasons was entirely different. In the first stage, which began in November and continued through April, there was an annual average depth of 0.045 m. The aquifer depth has been greatly influenced by rising precipitation and falling air temperature. The aquifer experiences an average decline of 0.15 m in the second portion, which runs from May to October. Aquifer depth has significantly decreased as a result of declining natural water supplies and rising agricultural water use. It is advised to utilize a crop scheme with reduced water need when rainfall reduces due to the strong effect of changes in aquifer depth from rainfall with a delay of one to three months ago.

     

Host (nanopores of zeolite Y)-guest (oxovanadium(IV) tetradentate schiff-base complexes) nanocomposite materials: synthesis,characterization and liquid phase hydroxylation of phenol with hydrogen peroxide

Oxovanadium(IV) tetradentate Schiff-base complexes; [VO(X₂-haacac)] (X = H, Cl, CH₃ and NO₂), X₂-haacac = substituted bis(2-hydroxyanil)acetylacetone; and encapsulated in the nanopores of zeolite NaY; [VO(X₂-haacac)]-NaY; have been synthesized and characterized. The host-guest nanocomposite materials; [VO(X₂-haacac)]-NaY; was characterized by chemical analysis and spectroscopic methods (FT-IR, UV/VIS, XRD, BET and DRS). The analytical data indicated a composition corresponding to the mononuclear complex of Schiff-base ligand. The characterization data showed the absence of extraneous complexes, retention of zeolite crystalline structure and encapsulation in the nanopores. Substitution of the aromatic hydrogen atoms of the Schiff-base ligand by electron withdrawing groups like −Cl, and −NO₂ has two major effects: (1) retention and concentration of the oxovanadium(IV) complex in the zeolite cavities is enhanced (due to the larger size of the substituents) and (2) the electronic and spectral properties of the encapsulated complex are modified. Liquid-phase selective hydroxylation of phenol with H₂O₂ to a mixture of catechol and hydroquinone in CH₃CN has been reported using oxovanadium(IV) Schiff-base complexes encapsulated in zeolite-Y as catalysts. Reaction conditions have been optimized by considering the concentration of substrate and oxidant, amount of catalyst, effect of time, volume of solvent and temperature. Under the optimized reaction conditions, [VO((NO₂)₂-haacac)]-NaY has shown the highest conversion of 42.3% after 6 h. All these catalysts are more selective toward catechol formation. Encapsulated oxovanadium(IV) complex is catalytically very efficient as compared to other neat complexes for the hydroxylation of phenol and is stable to be recycled without much deterioration.     

Determination of terbium(III) ions in phosphate rock samples by a Tb3+–PVC membrane sensor based on N,N-Dimethyl-N′, N″-bis(4-methoxyphenyl)phosphoramidate

A poly (vinyl chloride)-based membrane of N, N-Dimethyl-N′, N″-bis(4-methoxyphenyl)phosphoramidate (DMP) as a neutral carrier was prepared and investigated as a Tb³⁺-selective electrode. This electrode constructed with sodium tetraphenylborate (NaTPB) as the anion excluder and 2-nitrophenyl octyl ether (NPOE) as the plasticizer. Its performance was found to be the following: a Nernstian slope of 19.7 ± 0.4 mV per decade across a broad range (1.0 × 10^− 6 to 1.0 × 10^− 1 M); a detection limit of 8.0 × 10^− 7 M between the pH values of 3.5 and 8.0; additionally, the response time was about 10 s; usage of more than 2 months without any potential divergence; good Tb³⁺ selectivity over a wide variety of other metal ions. The membrane sensor was applied to the Tb³⁺ recovery from different water samples, determination of fluoride ions in mouth wash samples and the determination of Tb³⁺ in phosphate rock samples. It was also used as an indicator electrode in the potentiometric titration of Tb³⁺ ions with EDTA.     

An Experimental Investigation on the Copper Recovery from Flotation Tailing Dams by Reflotation

In this study, the possibility of copper recovery from flotation tailing of Mazraeh copper mine was investigated. Magnetic separation method was used for concentration of non-magnetic minerals, especially copper bearing minerals, from iron minerals. As a result, copper grade increased up to 0.18% and its recovery reached 86%. Due to mineral’s oxidized surface, accompanied oxide minerals and large quantities of fine particles (i.e. about 80% and 57% were finer than 37 and 15 μm in the sample, respectively), flotation of copper was very difficult. In this regard, the effects of important factors including solution pH, type and collector dosage, dispersant, impeller speed, type of frother, percent solid and surface sulfurization were studied. It was concluded that copper recovery of 52% and copper grade of 2.7% could be obtained under following conditions: pH: 11, Collector: Z11 with 40 g/t, Impeller speed: 1400 rpm, Frother: A65, percent solid: 10% and surface sulfurization by Na₂S with 1000 g/t. On the other hand, the addition of sodium silicate as a dispersant showed a negative effect on the flotation performance.     

Synthesis and characterization of new proton conducting hybrid membranes for PEM fuel cells based on poly(vinyl alcohol) and nanoporous silica containing phenyl sulfonic acid

Organic-inorganic hybrid proton exchange membranes were prepared from poly(vinyl alcohol) (PVA) and various amounts of nanoporous silica containing phenyl sulfonic acid groups. These hybrid membranes were prepared via co-condensation of functionalized nanoporous SBA-15 (SBA-ph-SO₃H) as hydrophilic inorganic modifier, glutaraldehyde (GLA) as cross-linking agent in a PVA matrix. These membranes were characterized for their morphology, thermal stability, electrochemical and physicochemical properties using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and water uptake studies. The SBA-ph-SO₃H/PVA composite membranes have a higher water retention and thermal stability than that of Nafion 117, perhaps because of responsibility of both acidic groups and nanoporous structure of silica additive. This work demonstrates the promising potential of new composite membranes for the development of high-performance and high-stability PEM fuel cells with improved proton conductivity.     

Influence of Aging Treatment on In-Situ Electrical Resistance Variation During Aging of Nickel-Rich NiTi Shape Memory Wires

Electrical resistance variations of Ni_50.9Ti_49.1 shape memory wires were studied during aging treatment at different temperatures via in-situ electrical resistance measurement. The results showed that during aging treatment, a cyclic behavior was observed in the electrical resistance variations, which could be related to the precipitation process. The evaluation of transition temperatures was conducted, after aging, using differential scanning calorimetry (DSC) analysis. The precipitation process is found to occur in four different stages. The results show that depending on the stress level around precipitates, two-, three-, or four-step martensitic transformation could be observed in DSC curves. In the points with maximum stress level (during precipitation process), four-step martensitic transformation is observed.