SILICA PHOSPHORIC ACID/NaNO2 AS A NOVEL HETEROGENEOUS SYSTEM FOR THE COUPLING OF THIOLS TO THEIR CORRESPONDING DISULFIDES

Silica phosphoric acid was prepared via reaction of silica chloride (I) and phosphoric acid. Thiols can be readily converted to their corresponding thionitrites with a combination of silica phosphoric acid (II), wet SiO ₂ , and sodium nitrite in dichloromethane at room temperature. Disulfides result from the homolytic cleavage of the sulfur–nitrogen bond of the unstable thionitrite and subsequent coupling of the resultant thiyl radicals.     

Al2O3/MeSO3H: A Novel and Recyclable Catalyst for One-Pot Synthesis of 3,4-Dihydropyrimidinones or Their Sulfur Derivatives in Biginelli Condensation

Al₂O₃/CH₃SO₃H (AMA) is an efficient catalyst for the three-component condensation reaction of aldehyde, 1,3-dicarbonyl compound, and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2-(1H)-ones in high isolated yield via this procedure, which works very effectively regardless of the electronic nature of the substituent on the ring, although electron-donating groups precipitate the rate of reaction. The catalyst is recyclable and stable at room temperature, and the reaction protocol is simple, is cost-effective, and gives good isolated yield with high purity.     

Community detection in social networks based on improved Label Propagation Algorithm and balanced link density

Nowadays, community detection has been raised as one of the key research areas in the online social networks mining. One of the most common algorithms in this field is label propagation algorithm (LPA). Even though the LPA method has advantages such as simplicity in understanding and implementation, as well as linear time complexity, it has an important disadvantage of the uncertainty and instability in outcomes, that is, the algorithm detects and reports different combinations of communities in each run. This problem originates from the nature of random selection in the LPA method. In this paper, a novel method is proposed based on the LPA method and the inherent structure, that is, link density feature, of the input network. The proposed method uses a sensitivity parameter (balance parameter); by choosing the appropriate values for it, the desired qualities of the identified communities can be achieved. The proposed method is called Balanced Link Density-based Label Propagation (BLDLP). In comparison with the basic LPA, the proposed method has an advantage of certainty and stability in the output results, whereas its time complexity is still comparable with the basic LPA and of course lowers than many other approaches. The proposed method has been evaluated on real-world known datasets, such as the Facebook social network and American football clubs, and by comparing it with the basic LPA, the effectiveness of the proposed method in terms of the quality of the communities found and the time complexity has been shown.     

Maps preserving a certain product of operators

Let $$\mathcal {A}$$ be a standard operator algebra on a Banach space $$\mathcal {X}$$ with $$ \dim \mathcal {X}\ge 3$$. In this paper, we determine the form of the bijective maps $$\phi :\mathcal {A}\longrightarrow \mathcal {A}$$ satisfying $$\begin{aligned} \phi \left( \frac{1}{2}(AB^2+B^2A)\right) = \frac{1}{2}[\phi (A)\phi (B)^{2}+\phi (B)^{2}\phi (A)], \end{aligned}$$for every $$A,B \in \mathcal {A}$$.     

Application of ZnO‐Al2O3 Nanocomposite as Nanocatalyst for Photodegradation of Acid Violet 5B

ZnO‐Al₂O₃ nanocomposite (ZANC) is used as nanocatalyst for photodegradation of acid violet 5B (AV5B) as an industrial dye. The experimental data shows that the degradation of AV5B is accelerated by ZANC and UV light. The effects of various parameters such as pH, hydrogen peroxide and ethanol are investigated on the photodegradation efficiency. Photocatalytic degradation rate of AV5B is increased by ethanol and hydrogen peroxide. Based on the kinetic studies, the rate constant of the photodegradation reaction is estimated 2.829 × 10^‐1 min^‐1.     

Comparative essential oil composition of aerial parts of Tanacetum dumosum Boiss. from Southern Zagros,Iran.

The essential oils of leaves and flowers of Tanacetum dumosum Boiss., an endemic medicinal shrub, were extracted by using hydrodistillation method and analysed using GC and GC–MS. A total of 43 and 44 compounds were identified in the essential oils from the leaves and flowers of T. dumosum, respectively. The major chemical constituents of leaves oil were borneol (27.9%), bornyl acetate (18.4%), 1,8-cineol (17.5%), α-terpineol (5.3%), cis-chrysanthenyl acetate (3.3%), camphene (2.7%) and terpinene-4-ol (1.9%), while the main components of the flower oil were isobornyl-2-methyl butanoate (41.1%), trans-linalyl oxide acetate (11.9%), 1,8-cineole (7.7%), thymol (4.2%), linalool (3.9%), camphor (2.9%), isobornyl propanoate (2.9%), α-terpineol (2.1%) and caryophyllene oxide (2.0%). Major qualitative and quantitative variations for some main chemical compounds among different aerial parts of T. dumosum were identified. High contents of borneol, bornyl acetate, 1,8-cineol and linalool in the leaves and flowers of T. dumosum show its potential for use in the food and perfumery industry.     

A rewarding-punishing coordination mechanism based on Trust in a divergent supply chain

Coordination of decentralized supply chains using contract design is a problem that has been widely addressed in the literature. We consider a divergent supply chain including a supplier and several retailers producing fashion products with short sale seasons. The retailers cooperate with the supplier as sales agents; i.e., they work in the framework of revenue sharing contracts. Because of their proximity to the market, retailers can provide more accurate demand forecasts to the supplier that is used to decide on issues such as capacity building and market prices with regard to retailers stiff due dates, different lead times and different price-dependent demand functions. To ensure abundant supply and cope with the demand variability, the retailers have an incentive to exaggerate their private forecast information. In this study, we propose a new rewarding-punishing coordination mechanism based on trust between supply chain tiers, considered as a differentiation factor between honest and deceptive partners. An optimization model is developed as a building block of this mechanism. An approximation method is used to simplify and solve the problem. The model is then implemented using Monte-Carlo simulation in four different situations, according to 10 different strategies for forecast information sharing. The findings from the tests show that the mechanism including trust as a decisional factor performs better than ‘No Trust’ mechanism in all situations. These results suggest that taking into account Trust in designing coordination mechanism may have significant influence on the financial performance of the supply chain.     

Study on the effect of laser parameters on wakefield excitation in femtosecond pulsed laser–plasma interaction using PIC method

Propagation of an intense short laser pulse through under-dense plasma can produce huge amplitude plasma wake field. A 3D particle in cell (PIC) method was used to simulate the wakefield generation for different laser parameters such as intensity, pulse duration, spot size and temporal pulse shape. Our study shows that the amplitude of wakefield is increased with laser intensity, but it is decreased with spot size. The results for pulse shape and pulse duration depend on their optimum values.