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1.
Russian Journal of Organic Chemistry - A highly efficient green protocol has been proposed for the synthesis of symmetrical S-aryl arenesulfonothioates by irradiation of N-hydroxy arenesulfonamides... 相似文献
2.
Zeolites have taken a leading position in petrochemical, fine, and bulk chemical industries due to their porous architecture, pore sizes, tunable acidity, and thermal stability. Various strategies of zeolites preparation, including template‐free, solvent‐free, and toxic mineral‐free strategies are summarized. Moreover, the zeolite synthesis using naturally occurring minerals and sustainable natural templates is also discussed, which involves the synthesis of nanocrystalline zeolites of different framework structures using plant‐based natural templates and biomass‐derived renewable chemicals. Overall this personal account provides the fundamentals of various sustainable synthetic strategies reported in the literature for the synthesis of zeolites with suitable examples that will be useful for the students and will motivate experienced researchers to develop various novel sustainable methods for the synthesis of zeolites and other inorganic materials of industrial relevance. 相似文献
3.
For the first time, intensification of monooleoyl glycerol (MOG) synthesis has been investigated in an ultrasonic-infrared-wave (USIRW) promoted batch reactor. Esterification of octadecanoic acid (ODA) with glycerol (Gl) has been conducted [using Amberlyst 36 wet catalyst] in three different reactors, namely traditional batch reactor (TBR), infrared wave promoted batch reactor (IRWPBR), and USIRW-promoted batch reactor (USIRWPBR) to assess the relative efficacy. The energy-efficient USIRWPBR remarkably intensifies the ODA-Gl esterification as manifested through superior ODA conversion (92.5 ± 1.25%) compared to that achieved in IRWPBR (79.8 ± 1.2%) and TBR (36.39 ± 1.25%). The most favorable reaction condition for optimum ODA conversion and maximum MOG yield was identified through statistical optimization over a selected parametric range, namely 3-5 Gl/ODA mole ratio, 0.004-0.006 g/mL Amberlyst 36 catalyst concentration, 300-700 rpm impeller speed, and 333-353 K reaction temperature. The present study also reports the formulation and validation of an innovative reaction kinetics, that is, concurrent noncatalytic and heterogeneously catalyzed (CNCHC) reaction mechanism in addition to the conventional heterogeneous kinetic models (LH and Eley-Rideal mechanisms). Under combined USIRW, the CNCHC esterification mechanism could best describe ODA-Gl esterification (R2 = 0.98) compared to LH (R2 = 0.97) and Eley-Rideal (R2 = 0.88) mechanisms. The optimal product (MOG) was characterized by differential scanning calorimetry and thermogravimetric analysis to assess its crystallization property and thermal stability for possible application as plasticizer/fuel additives. 相似文献
4.
Shashank Shukla Joseph Favata Vikas Srivastava Sina Shahbazmohamadi Anubhav Tripathi Anita Shukla 《Journal of polymer science. Part A, Polymer chemistry》2020,58(10):1365-1379
Developing optimized hydrogel products requires an in-depth understanding of the mechanisms that drive hydrogel tunability. Here, we performed a full 4 × 4 factorial design study investigating the impact of gellan, a naturally derived polysaccharide (1%, 2%, 3%, or 4% w/v) and CaCl2 concentration (1, 3, 7, or 10 mM) on the viscoelastic, swelling, and drug release behavior of gellan hydrogels containing a model drug, vancomycin. These concentrations were chosen to specifically provide insight into gellan hydrogel behavior for formulations utilizing polymer and salt concentrations expanding beyond those commonly reported by previous studies exploring gellan. With increasing gellan and CaCl2 concentration, the hydrogel storage moduli (0.1–100 kPa) followed a power-law relationship and on average these hydrogels had higher liquid absorption capability and greater total drug release over 6 days. We suggest that the effects of gellan and CaCl2 concentration and their interactions on hydrogel properties can be explained by various phenomena that lead to increased swelling and increased resistance to network expansion. 相似文献
5.
Divya Iyer Vaqar M. S. Syed Samanvaya Srivastava 《Journal of polymer science. Part A, Polymer chemistry》2021,59(22):2895-2904
The addition of monovalent salts to polyelectrolyte complexes (PECs) comprising oppositely charged polyelectrolytes results in diminishing propensity for complexation, leading to complexes with higher water contents and lower moduli. However, the corresponding influence of multivalent ions on polyelectrolyte complexation has not yet been explored beyond enhanced screening effects. Here, we elucidate the significant impact of the valency of the salt cation on the composition, ion partitioning, and viscoelasticity of charge-matched PECs comprising sodium salt of poly(acrylic acid) and poly(allylamine hydrochloride). Notably, preferential partitioning of divalent cations (Ca2+ and Sr2+) into the complexes is observed, in stark contrast to the depletion of monovalent ions (Na+) from the complexes. Concomitantly, electrostatic bridging of polyanion chains by divalent ions is found to hinder their relaxation, manifesting as a non-monotonic evolution of the shear moduli of the complexes with increasing divalent salt concentrations. Relatedly, a failure of time-salt and time-ionic strength superposition approaches in presence of divalent ions is demonstrated, highlighting the nontrivial influence of these ions on chain relaxation behavior. 相似文献
6.
Lot‐sizing policies for deterioration items under two‐level trade credit with partial trade credit to credit‐risk retailer and limited storage capacity 下载免费PDF全文
Jui‐Jung Liao Kuo‐Nan Huang Kun‐Jen Chung Pin‐Shou Ting Shy‐Der Lin H. M. Srivastava 《Mathematical Methods in the Applied Sciences》2017,40(6):2122-2139
The main purpose of this article is to investigate the optimal wholesaler's replenishment decisions for deterioration items under two levels of the trade credit policy and two storage facilities in order to reflect the supply chain management situation within the economic order quantity framework. In this study, each of the following assumptions have been made: (1) The own warehouse with limited capacity always is not sufficient to store the order quantity, so that a rented warehouse is needed to store the excess units over the capacity of the own warehouse; (2) The wholesaler always obtains the partial trade credit, which is independent of the order quantity offered by the supplier, but the wholesaler offers the full trade credit to the retailer; (3) The wholesaler must take a loan to pay his or her supplier the partial payment immediately when the order is received and then pay off the loan with the entire revenue. Under these three conditions, the wholesaler can obtain the least costs. Furthermore, this study models the wholesaler's optimal replenishment decisions under the aforementioned conditions in the supply chain management. Two theorems are developed to efficiently determine the optimal replenishment decisions for the wholesaler. Finally, numerical examples are given to illustrate the theorems that are proven in this study, and the sensitivity analysis with respect to the major parameters in this study is performed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
7.
On the growth and approximation of entire functions represented by Laplace–Stieltjes’ transformation
In the present paper, we obtain the characterization of various growth parameters of an entire function F(s) represented by Laplace–Stieltjes transformation in terms of the rate of decrease of \(E_n ( {F,\beta } ),\)where \(E_n ( {F,\beta } )\) represents the error in approximating the function F(s) by exponential polynomials. 相似文献
8.
M.?A.?BouticheEmail author M.?Rahmani H.?M.?Srivastava 《Mediterranean Journal of Mathematics》2017,14(2):89
In this paper, we propose and derive several new explicit formulas of the generalized Bernoulli and Euler polynomials in terms of the generalized Stirling numbers of the second kind. A study of some families of the modified generalized Euler polynomials yields an interesting algorithm for calculating the generalized Euler polynomials. 相似文献
9.
The demand for quick, accurate, and affordable point-of-care (POC) devices increases with the advancement in the dimensions of nanotechnology and digital interfaces (Internet of Things). The future of diagnostic requires the platform which can provide us the following benefits i. e., on-site detection, qualitative as well as quantitative analysis, easy to use, portable, low sample requirement, cost-effective, and have multiplexing proficiency. Multiplex biosensing platforms (MBPs) have the above following advantages so are going to be mostly used in various healthcare applications in near future. MBPs have the potential to fulfill the ‘ASSURED’ criteria specified by the World Health Organization (WHO) for remote-limited settings. This review paper focuses on miniaturized platforms that have multiplexing benefits for the bioanalysis of different clinical samples related to various healthcare applications. In addition to this, screening of pesticides, antibiotics, and hazardous metal ions with these surface-engineered devices has also been accounted in food and environmental samples. Some of the advanced techniques including microfluidics (Lab-on-a-chip), wearable smart devices, and CRISPR/Cas system for multiplexing applications are briefly described here. Furthermore, various needs, challenges, and prospects in commercializing these multiplexed surface-engineered devices have been discussed in this review. 相似文献
10.
Ranveer Singh Maxime Vallet Vijay Singh Sanjeev K. Srivastava Alain Claverie Tapobrata Som 《Surface and interface analysis : SIA》2023,55(2):151-161
Due to its outstanding physical properties, CdTe is used to fabricate high efficiency solar cells. However, its high work function poses a challenge, and hence, to fabricate an efficient CdTe-based solar cell, Cu-doping may be useful. Here, we present the role of temperature-dependent Cu-doping in radio frequency sputter-deposited CdTe films and the related changes occurring in their optical, electrical, structural and microstructural properties. For instance, Cu-doping at different temperatures leads to an increase in the grain size and a reduction in the optical reflectance with increasing temperature. In addition, Kelvin probe force microscopy measurements reveal that the work function is found to be smaller corresponding to the annealing temperature of 473 K, whereas resistivity measurements show that it decreases with increasing temperature (the lowest value of resistivity is found to be 1.8 × 10−2 Ω-cm). To understand the electronic structure of CdTe before and after Cu-doping, we have carried out first-principles density functional theory (DFT) simulation, which reveals a strong hybridization among Cu, Cd and Te atoms. This study paves the way to fabricate efficient Cu-doped CdTe-based solar cells. 相似文献