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Aldol reactions (self- and cross-aldol condensations) for conjugated enone synthesis were efficiently performed on large-sized Cs⁺ single sites (1 wt %) confined in β-zeolite channels in toluene, which showed the highest level of catalytic aldol condensation activity among reported zeolite catalysts. In general, aldol condensation reactions for C–C bond synthesis can proceed by acids (e.g., H⁺), bases (e.g., OH⁻), enolate species, and acidic or basic solid catalysts. However, the Cs⁺ single site/β sample without significant acid–base property showed unprecedented, efficient, and reusable catalysis for self-aldol and cross-aldol condensations. Intrinsically inactive Cs⁺ single sites due to the noble-gas electronic structure were transformed to active Cs⁺ single sites in β-zeolite channels. Cs⁺/β has many advantages such as broad substrate scope, eco-friendliness, high product selectivity and yield, and simple work-up procedure. Thus, the Cs⁺ single site/β provides an attractive and useful methodology for practical C–C bond synthesis. On the basis of the Cs⁺/β characterization by X-ray photoelectron spectroscopy (XPS), in situ X-ray absorption fine structure (XAFS) (X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)), and temperature-programmed desorption (TPD), density functional theory (DFT) calculations of the self- and cross-aldol condensation reaction pathways involving the transition states on the Cs⁺ single site in β-zeolite channel revealed nontraditional concerted interligand bond rearrangement mechanisms.

We report the transformation of Cs+ ions with an inactive noble gas electronic structure to active Cs+ single sites chemically confined in Y zeolite pores (Cs+/Y), which provides an unprecedented catalysis for oxidative cyanation (ammoxidation) of Csp3–H bonds with O2 and NH3, although in general, alkali and alkaline earth metal ions without a moderate redox property cannot activate Csp3–H bonds. The Cs+/Y catalyst was proved to be highly efficient in the synthesis of aromatic nitriles with yields >90% in the selective ammoxidation of toluene and its derivatives as test reactions. The mechanisms for the genesis of active Cs+ single sites and the ammoxidation pathway of Csp3–H bonds were rationalized by density functional theory (DFT) simulations. The chemical confinement of large-sized Cs+ ions with the pore architecture of a Y zeolite supercage rendered the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap reduction, HOMO component change, and preferable coordination arrangement for the selective reaction promotion, which provides a trimolecular assembly platform to enable the coordination-promoted concerted ammoxidation pathway working closely on each Cs+ single site. The new reaction pathway without involvement of O2-dissociated O atom and lattice oxygen differs from the traditional redox catalysis mechanisms for the selective ammoxidation.

Tiger Hill, a notified reserve forest is the highest point around Darjeeling town in Eastern Himalayan Hotspot. Soil nutrition of this forest area depends on nutrient recycling where phosphate solubilising microorganisms (PSM) has crucial role to play as it solubilises insoluble phosphorus salt to soluble forms. But, with rise in use of toxic chemicals these microbes are at threat. This research initiative explores isolation of PSM from Tiger hill forest soil to detect pesticide, antibiotic, antifungal and heavy metal tolerance. Soil sample from tiger hill has moisture (18.55%), pH (3.87), organic carbon (1.187%), total Nitrogen (1.02%) and Phosphorus in P2O5 form (10ppm). Isolation and screening of PSM were conducted on Pikovskaya’s agar medium. In vitro tolerance assay was performed to detect degree of tolerance in isolated PSM-consortium (PSMC). Pesticides like Fipronil, Thiomethoxame, Emamectin benzoate, Deltamethrin, Flubendiamide, Spiromesifen, Fenazaquin and Phorate exhibited complete to high degree of tolerance. PSMC was fully tolerant to antibiotic like Augmentin, Erythromycin, Chloramphenicol, Ofloxacin, Co-Trimoxazole, Cefotaxime; antifungal Itraconazole and Fluconazole. Mild tolerance towards heavy metal salts like As2O3, SnCl2, CdCl2, CuCl2, CdSO4 and CuSO4 were detected. Synergestic effect of cells present in the isolated PSMC may also be an added advantageous property to tolerate pesticides, antibiotic, antifungal and heavy metal salts.

In this paper, the Staff Transfer Problem (STP) in Human Resource Management is addressed as a stable matching problem. Earlier, formulation of this problem was of scheduling/allocation type. Here, the stable matching formulation is completely a new and more practical approach to the problem. This new formulation involves two preference lists: the first list contains the offices/locations preferred by the employees undergoing transfer and the second list contains the employees preferred by the employer of an office/location where those employees want to be transferred. The capacity of an office/location would act as a hard constraint. While matching these two lists, the objective is to maximize the number of transfers and at the same time to stabilize the matching, i.e., to minimize the number of blocking pairs. The resulting STP instance belongs to an instance of Maximum Size Minimum Blocking Pair Stable Matching with incomplete preference list (MAX SIZE MIN BP SMI) and has been proved in this paper to be NP-hard. As the problem is new in formulation, no previous work, method or result is available. There was no preference in selecting meta-heuristics. Among a large number of existing meta-heuristics, some most widely used meta-heuristics, namely, Simulated Annealing, Genetic Algorithms, Tabu Search and some variants of them have been chosen. Based on them four meta-heuristic approaches have been proposed, namely, btSA_match, gtSA_match, GA_match and TS_match. The variants btSA_match and gtSA_match are obtained from modifications made upon Simulated Annealing. EGA_match and TS_match are based on modified Genetic Algorithms and Tabu Search respectively. As there is no previous result in the existing literature, the performance has been compared among these four methods. It is observed that, variants of Simulated Annealing (SA) outperform others w.r.t. the performance metrics. The SA-variant with greedy nature, incorporated with a tabu list (gtSA_match) has shown that the best result on the basis of statistical analysis.

Catalytic benzene C-H activation toward selective phenol synthesis with O2 remains a stimulating challenge to be tackled. Phenol is currently produced industrially by the three-steps cumene process in liquid phase, which is energy-intensive and not environmentally friendly. Hence, there is a strong demand for an alternative gas-phase single-path reaction process. This account documents the pivotal confined single metal ion site platform with a sufficiently large coordination sphere in β zeolite pores, which promotes the unprecedented catalysis for the selective benzene hydroxylation with O2 under coexisting NH3 by the new inter-ligand concerted mechanism. Among alkali and alkaline-earth metal ions and transition and precious metal ions, single Cs+ and Rb+ sites with ion diameters >0.300 nm in the β pores exhibited good performances for the direct phenol synthesis in a gas-phase single-path reaction process. The single Cs+ and Rb+ sites that possess neither significant Lewis acidic-basic property nor redox property, cannot activate benzene, O2 , and NH3 , respectively, whereas when they coadsorbed together, the reaction of the inter-coadsorbates on the single alkali-metal ion site proceeds concertedly (the inter-ligand concerted mechanism), bringing about the benzene C-H activation toward phenol synthesis. The NH3 -driven benzene C-H activation with O2 was compared to the switchover of the reaction pathways from the deep oxidation to selective oxidation of benzene by coexisting NH3 on Pt6 metallic cluster/β and Ni4 O4 oxide cluster/β. The NH3 -driven selective oxidation mechanism observed with the Cs+ /β and Rb+ /β differs from the traditional redox catalysis (Mars-van Krevelen) mechanism, simple Langmuir-Hinshelwood mechanism, and acid-base catalysis mechanism involving clearly defined interaction modes. The present catalysis concept opens a new way for catalytic selective oxidation processes involving direct phenol synthesis.

Objective The primary objective is to compare miscarriage rates in frozen-thawed embryo transfer (FET) cycles, according to the endometrial preparation used either artificial through the administration of exogenous estrogen and progesterone or natural without any treatment, during a spontaneous ovulatory cycle. The secondary objective is to compare the live birth rates between the two endometrial preparations. Study design This is a retrospective study done at KK Women’s and Children’s Hospital Singapore. We included women who underwent FET cycles either with hormone replacement treatment (HRT) or no treatment (natural) for the endometrial preparation, regardless of their cycle number, from 1 January 2011 till 31 December 2015. Results A total of 2,752 FET cycles were included in our analysis. The natural cycle followed by vaginal progesterone support was used in 1,221 cycles and the HRT cycle with estrogen and vaginal progesterone was used in 1,531 cycles. There is a significantly higher miscarriage rate in the HRT group (38.4%) compared with the natural group (22.3%). The live birth rate is significantly higher in the natural group (22.8%) compared with the HRT group (17.3%). The multivariate analysis further shows that the HRT therapy is independently associated with an increased risk of miscarriage (adjusted odds ratio 2.05; 95% confidence interval 1.45–2.90; [Formula: see text] Conclusion We have shown in this study that the miscarriage rate is higher in the HRT FET group and that this increased miscarriage rate translates into a lower live birth rate in the HRT group. Thus, we conclude that patients with regular menstrual cycles should be offered a natural FET cycle to achieve better outcomes in terms of live birth rate and reducing the miscarriage rate.

An environmentally benign and cost-effective synthesis of benzonitrile is reported by direct oxidative cyanation of aromatic Csp3-H bonds of toluene over Ag(I)/Cr2O3 nanostructured catalyst. The catalyst was prepared by a hydrothermal route using cationic surfactant cetyltrimethylammonium bromide and was characterized by powder XRD, XPS, SEM, TEM, TGA, TPD, TPR, UV-visible, FTIR, XANES, and ICP-AES methods. Conjugal effect of Lewis plus Bronsted acidity coupled with Ag Cr interfacial synergistic interaction appears as detrimental for its high catalytic activity and selectivity (98.4%) for benzonitrile. In situ DRIFTS analysis suggested that the catalytic system proceeded via a reaction pathway explained by Mars-van Krevelen mechanism.

Re-orchestration is a crucial operational requirement secured by Software-Defined Wireless Sensor Networks (SDWSN). Herein, WSN flexibility involves functional identification, definition, modularization, and virtualization. These components support sensor network software-control and allow for dynamically redefining the network topology and operational behavior. This paper reflects the core ideology behind the proposed cloud-based cyber-physical organizational structure. This utilizes the virtualization and testing of the functionalities that edge towards desired re-orchestrations. The physical implementation of re-orchestration process, however, may cause network operational disruption for a brief period of time. This research work reflects the parameters involved in network re-orchestration process. Analysis of an example performance indicator that influences the downtime in SDWSN during re-orchestration is offered. Clarity of these involvements can offer significant help in supporting planning for reducing this ‘down time’.

The well-known cumene process via an explosive cumene hydroperoxide intermediate in liquid phase currently employed for phenol production is energy-intensive and not environmentally friendly. Therefore, there is a demand for an alternative single-step gas-phase catalysis process. According to the conventional catalysis concept, selective oxidation reactions are promoted by redox catalysts and not by acid–base catalysts. In general, alkali and alkaline earth metal ions cannot activate each of benzene, O2, and N2O when they adsorb separately. However, we observed an unprecedented catalysis of single alkali and alkaline earth metal ion sites incorporated into zeolite pores for the selective oxidation of benzene to phenol with N2O and O2 + NH3, thereby providing a single-site catalytic platform with high selectivity. Among alkali and alkaline earth metal ions, single Cs+ and Rb+ sites with ion diameters of >300 pm in the pores of β-zeolites exhibited remarkable selectivity for benzene C–H activation to phenol catalysis in a concerted reaction pathway.

While the equivalence between online and traditional classrooms has been well-researched, very little of this includes college-level introductory Physics. Only one study explored Physics at the whole-class level rather than specific course components such as a single lab or a homework platform. In this work, we compared the failure rate, grade distribution, and withdrawal rates in an introductory undergraduate Physics course across several learning modes including traditional face-to-face instruction, synchronous video instruction, and online classes. Statistically significant differences were found for student failure rates, grade distribution, and withdrawal rates but yielded small effect sizes. Post-hoc pair-wise test was run to determine differences between learning modes. Online students had a significantly lower failure rate than students who took the class via synchronous video classroom. While statistically significant differences were found for grade distributions, the pair-wise comparison yielded no statistically significance differences between learning modes when using the more conservative Bonferroni correction in post-hoc testing. Finally, in this study, student withdrawal rates were lowest for students who took the class in person (in-person classroom and synchronous video classroom) than online. Students that persist in an online introductory Physics class are more likely to achieve an A than in other modes. However, the withdrawal rate is higher from online Physics courses. Further research is warranted to better understand the reasons for higher withdrawal rates in online courses. Finding the root cause to help eliminate differences in student performance across learning modes should remain a high priority for education researchers and the education community as a whole.

Connecting wireless sensor networks (WSNs) to remote servers or clouds through the Internet of Things inspires the formation of a highly complex system. This has significant potential to encourage WSN softwarization. Such a network enables interaction between the physical and virtual sensor network, allowing for flexibility within the physical system to adapt with the dynamics of the service requirements. An architecture of a test environment with adaptive quality of service (AQoS) has been presented. The concept provides an avenue for a flexible system that is capable of reacting to dynamic changes of process demands. Physical network performance can be predicted by analyzing the historical data in the background on a network simulator or virtual network. This in turn allows for estimation of the necessary adjustments needed to improve the network performance without disturbing the physical system. This paper reports the experimentation and applicability of user-driven AQoS models on the system. Early stages of testing the organization, taking into account the system behavior and subsequent reaction to necessary adjustment of the WSN operational configuration, has shown encouraging results.

Materials behave differently when subjected to loads at different strain rates. The study of this field is very important in the analysis of the behavior and failure of components and structures that are subjected to dynamic loads. In the present work, the high strain rate behavior of steel used in armour applications has been investigated through tensile tests at low and medium strain rates and high rate compression tests in SHPB set up. The study shows that the material exhibits moderate strain rate sensitivity and is fairly constant over a wide range of strain rates.

Catalytic benzene C-H activation toward selective phenol synthesis with O

Ag nanoparticles (with 2–5 nm size) supported on Mn3O4 nanorods were prepared in the presence of the cationic surfactant cetrimonium bromide using a hydrothermal method. The material was characterized in detailed by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning transmission electron microscopy-mapping, Raman spectroscopy, Fourier-transformed infrared spectroscopy and inductively coupled plasma-atomic emission spectroscopy. Electron microscopy studies revealed the formation of 1D nanorods morphology. XRD revealed the formation of Mn3O4 spinel phase and TEM showed that ultrasmall-sized metallic Ag-nanoparticles deposited on Mn3O4 spinel (nanorods). This Ag/Mn3O4 nanomaterial exhibited excellent catalytic activity in the cyclohexane oxidation reaction at room temperature. The impacts of various reaction parameters (e.g. time, substrate : H2O2 molar ratio etc.) were investigated in detail. A detailed characterization study demonstrated the correlation between the physicochemical properties of the Ag–Mn oxide nanorods and their catalytic performance. A cyclohexane conversion of 88% with 75% cyclohexanone selectivity with an overall C6 selectivity (cyclohexanol + cyclohexanone) of 100% was accomplished at room temperature. The Ag/Mn3O4 catalyst hardly exhibited leaching up to eight reuses, proving its true heterogeneous nature.

We have synthesized Ag nanoparticles (with sizes of 2–5 nm) supported on 1D Mn3O4 spinel nanorods by a surfactant-assisted single-step preparation method using a room-temperature synthesis protocol for the first time. The unique 1D rod-like morphology increases the amount of adsorption sites of the support, leading to less sintering and higher dispersion of Ag nanoparticles, resulting in significantly enhanced catalytic activity for the industrially important selective oxidation of 3-picoline to niacin. The catalyst was thoroughly characterized by XRD, XPS, SEM, TEM, Raman, FTIR and UV-visible spectroscopy. XRD revealed the formation of Ag nanoparticles supported on hausmannite-type tetragonal Mn3O4. Electron microscopy studies confirmed the formation of the 1D structure of the catalyst. The generation of this 1D nanostructure has been revealed in detail and correlated with its superior catalytic activity. Various reaction parameters like temperature, substrate : H2O2 molar ratio, reaction time, etc. were studied. A niacin selectivity of 97%, with a 3-picoline conversion of 55%, was achieved over this catalyst at 70 °C. It was noticed that, when halide ions (Br−) were present in the synthesis gel mixture, only then were the morphology and activity of the catalyst proven to be superior. The thorough dispersion of Ag nanoparticles on Mn3O4 nanorods and the synergy displayed between Ag nanoparticles and Mn3O4 are the detrimental factors for its high activity. The catalyst was reused 5 times and thereby displayed its true heterogeneous character.

We report the preparation of Ag/WO 3 nanobars, mediated by cationic surfactant CTAB through hydrothermal route. XRD revealed the formation of metallic Ag supported on monoclinic WO 3 phase and TEM diagram showed the formation of bar-like structure, where supported Ag nanoparticles are in the range between 2 and 7 nm. The catalyst exhibited high activity for selective oxidation of cyclohexanone to caprolactone with H 2 O 2 . A cyclohexanone conversion of 97% with 99% caprolactone selectivity was achieved over this catalyst at 80 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 5 reuses and proved its efficiency in the oxidation of other cycloalkanones also.

Silver–tungsten oxide wafer-like nanoarchitectures were prepared for the first time for selective epoxidation of a wide range of alkenes to their corresponding epoxides with high yield. The wafer-like nanostructure provides sufficient contact between the substrate/catalyst and overcomes the steric influence of the bulkier substrates. The influence of various reaction parameters, such as temperature, substrate to oxidant molar ratio, reaction time, and so forth, were investigated in detail. The catalyst was characterized by XRD, XPS, EXAFS, ICP-AES, RAMAN, SEM, and TEM. Raman studies prove that the formation of peroxo tungsten species is responsible for epoxiation reaction. High stability and recyclability of the Ag–W catalyst is also observed under the investigated conditions.

Cu (II) nanoclusters supported on nanocrystalline zirconia catalyst (with size ~15 nm), was prepared by using cationic surfactant cetyltrimethylammonium in a hydrothermal synthesis method. The catalyst was characterized by XRD, XPS, TGA, SEM, TEM, FTIR and ICP-AES. The catalyst was found to be efficient in selective oxidation of n-hexane to 2-hexanol. An n-hexane conversion of 55%, with a 2-hexanol selectivity of 70% was achieved over this catalyst in liquid phase, without the use of any solvent. The catalyst can be reused several times without any significant activity loss.

Phenol is an important commodity chemical, and the catalytic conversion of benzene to phenol by molecular oxygen with minimum waste production is of high significance from an academic as well as industrial point of view. We have developed a facile synthesis method for the preparation of 2–8 nm Cu(II) oxide nanoparticles supported on CuCr2O4 spinel nanoparticles (with size ∼55 nm). Detailed characterization of the material was carried out by XRD, SEM, TEM, XPS, FTIR, TGA, TPR, BET surface area, XANES, and ICP-AES methods. XRD and XPS analyses revealed that the main phase is CuCr2O4 spinel, where a small amount of CuO is dispersed on it. The catalyst was highly active for selective oxidation of benzene to phenol with air as oxidant. The influence of reaction parameters was investigated in detail. The high catalytic performance of the catalyst is due to the ultrasmall size of Cu(II) oxide nanoparticles and the strong synergy between ultrasmall Cu(II) oxide and CuCr2O4 spinel nanoparticles that plays a pivota...

Heterogeneous catalysts comprising silver nanoparticles supported on nanostructured tungsten oxide were applied for room temperature oxidative coupling of aniline to azoxybenzene, an important chemical intermediate and a chemical of industrial interest. The catalytic protocol features high activity and selectivity to the target product azoxybenzene with a turnover number of ∼368. The catalyst was characterized by XRD, XPS, ICP-AES, FT-IR, TGA, EXAFS, SEM and TEM. The silver-tungsten nanomaterial acts as an excellent catalyst for selective oxidation of aniline to azoxybenzene using H2O2 as an oxidant. An aniline conversion of 87% with 91% selectivity of azoxybenzene was achieved without the use of any external additives. Moreover, a high stability and recyclability of the catalyst is also observed under the investigated conditions.

We report here cetyl alcohol-promoted synthesis of spherical CuCr2O4 spinel nanoparticles with almost uniform morphology, prepared hydrothermally. Detailed characterization of the material was carried out by XRD, XPS, ICP-AES, SEM, TEM, and TGA. XRD revealed the exclusive formation of the CuCr2O4 spinel phase and TEM showed the formation of a 20–40 nm particle size. The catalyst was highly active for selective oxidation of benzene to phenol with H2O2. The influence of reaction parameters was investigated in detail. The catalyst was found to be selective for hydroxylation of other aromatic alkanes as well. The reusability of the catalyst was tested by conducting the same experiments with the spent catalyst and it was found that the catalyst does not show any significant activity loss even after 5 reuses. The benzene conversion of 67% with 94% phenol selectivity was achieved at 75 °C temperature.

We report here preparation of CuCr 2 O 4 spinel nanoparticle catalyst, mediated by cationic surfactant CTAB in hydrothermal route. XRD revealed the formation of CuCr 2 O 4 spinel phase and TEM showed the particle size of 30–60 nm. The catalyst was speculated to be highly active for selective oxidation of cyclohexane to cyclohexanone with H 2 O 2 . A cyclohexane conversion of 70% with 85% cyclohexanone selectivity was achieved over this catalyst at 50 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 8 reuses and proved its efficacy in the oxidation of other cycloalkanes also.

A facile hydrothermal synthesis method is developed to prepare Cu(II) nanoclusters supported on a nanocrystalline W(VI) oxide catalyst with sizes between 35 and 65 nm. Detailed characterization of the material was carried out by XRD, XPS, SEM, TEM, STEM-mapping, Raman, FTIR, TGA, UV-visible spectroscopy and ICP-AES. The catalyst was highly active for selective oxidation of cyclohexane to adipic acid with H2O2. The influence of reaction parameters such as temperature, substrate to oxidant molar ratio, reaction time, etc. was investigated in detail. The reusability of the catalyst was tested by conducting the same experiments with the spent catalyst and it was found that the catalyst did not show any significant activity loss even after 4 reuses. A cyclohexane conversion of 75% with 88% adipic acid selectivity was achieved over this catalyst at 70 °C temperature.

Cetyl alcohol-mediated water-based preparation of nanocrystalline Ag/Mn3O4 catalyst has been reported in a one-pot preparation method. This catalyst has been characterized by XRD, XPS, SEM, TEM, STEM-mapping, FTIR, Raman and ICP-AES. Electron microscopy displayed the formation of whisker-like one-dimensional structure. TEM-images revealed the formation of ultrasmall Ag (with average size 5 nm), anchored on hausmannite-type tetragonal Mn3O4 spinel (with diameter 30–40 nm). It was found that the catalyst can effectively oxidize styrene with molecular O2 as oxidant. The effect of different reaction parameters like reaction temperature, pressure of oxygen gas, reaction time etc. have been investigated in detail. A styrene conversion of 67% with a styrene-oxide selectivity of 100% accomplished over this catalyst. Nano-whiskers like unique morphology of the catalyst and the thorough dispersion of Ag nanoparticles on Mn3O4 spinel support are the detrimental factors of the reactivity of the catalyst. The catalyst did not show any leaching up to five reuses, showing its true heterogeneity nature.

Cationic surfactant cetyltrimethylammonium bromide-mediated water-based preparation of nanocrystalline Ag–WO3 catalyst has been reported in a one-pot preparation method. This catalyst has been characterized by XRD, XPS, SEM, TEM, STEM-mapping, FTIR, Raman, TGA, and ICP-AES. SEM images displayed the formation of an aloevera-like structure. TEM-images revealed the formation of ultrasmall Ag (with average size 5 nm), anchored on monoclinic WO3 rods (with diameters in the range between 80 and 120 nm). It was found that the catalyst can effectively oxidize styrene with H2O2 as the oxidant. The effects of different reaction parameters have been studied in detail. A styrene conversion of 75% with a styrene-oxide selectivity of 55% and a styrene conversion of >99% with a benzaldehyde selectivity of 88% were accomplished over this catalyst, varying different reaction conditions. The catalyst did not show any leaching for up to five reuses, showing the true heterogeneity of the catalyst. However, significant H2O2 decomposition occurs on the catalyst necessitating its usage in four-fold excess.

We report a facile hydrothermal synthesis method to prepare CuCr2O4 spinel catalyst nanoparticles 20−60 nm in size, mediated by cationic surfactant cetyltrimethylammonium bromide. Detailed characterization of the material was carried out by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and inductively coupled plasma–atomic emission spectroscopy (ICP-AES). XRD analysis revealed the formation of a CuCr2O4 spinel phase and TEM analysis showed that the particle size was 20−60 nm. The catalyst was highly active for selective oxidation of ethylbenzene to acetophenone with H2O2. The influence of reaction parameters such as temperature, substrate-to-oxidant molar ratio, reaction time, etc. were investigated in detail. The reusability of the catalyst was tested by conducting same experiments with the spent catalyst, and it was found that th...

We have prepared silver nanoparticles (AgNPs) supported on tungsten oxide (WO3) in presence of cetyltrimethyl ammonium bromide (CTAB), a catinic surfactant. The catalyst was characterized by XRD, ICP-AES, FT-IR, SEM and TEM. The catalyst was highly active for selective oxidation of cyclooctene to cyclooctene oxide at room temperature with H2O2. The reusability of the catalyst which is a prerequisite for practical applications was performed and it was found that the catalyst exhibits no significant changes in its catalytic activity even after three reuses. A cyclooctene conversion of 55% with cyclooctene oxide selectivity of ~99% was achieved over this catalyst

We have developed a facile one-pot synthetic strategy to prepare Ag/WO3 nanostructure materials with different morphologies using a cationic surfactant, cetyltrimethylammonium bromide. These materials were employed as catalysts in the direct synthesis of toluene to benzaldehyde using H2O2. The morphology of the Ag/WO3 materials can be varied by changing the synthesis parameters. The size and shape of the Ag/WO3 nanostructure catalyst has direct influence on the toluene conversion and benzaldehyde selectivity. The effect of different reaction parameters like reaction temperature, H2O2 to toluene molar ratio, reaction time, and so forth have been studied in detail. The Ag/WO3 catalyst with ∼7 nm silver nanoparticles on the WO3 nanorod with a diameter ∼60 nm showed the best catalytic activity of 42% toluene conversion with 93% benzaldehyde selectivity. The catalyst did not show any leaching up to four reuses, showing the true heterogeneity of the catalyst.

Propylene oxide (PO) is a versatile chemical intermediate, and by volume it is among the top 50 chemicals produced in the world. The catalytic conversion of propylene to PO by molecular oxygen with minimum waste production is of high significance from an academic as well as an industrial point of view. We have developed a new synthesis strategy to prepare 2–5 nm metallic silver nanoparticles (AgNPs) supported on tungsten oxide (WO3) nanorods with diameters between 30 and 40 nm, in the presence of cationic surfactant (cetyltrimethylammonium bromide: CTAB), capping agent (polyvinylpyrrolidone: PVP), and hydrazine. The synergy between the surface AgNPs and WO3 nanorods facilitates the dissociation of molecular oxygen on the metallic Ag surface to produce silver oxide, which then transfers its oxygen to the propylene to form PO selectively. The catalyst exhibits a PO production rate of 6.1 × 10–2 mol gcat–1 h–1, which is almost comparable with the industrial ethylene-to-ethylene oxide production rate.

Cationic surfactant cetyltrimethylammonium chloride-mediated hydrothermal preparation of CuCr2O4 spinel nanoparticles has been reported. This CuCr2O4 spinel nanoparticle catalyst has been characterized by XRD, XPS, SEM, TEM, TGA, and ICP-AES. Characterization results showed the formation of CuCr2O4 spinel nanoparticles with sizes between 25 and 50 nm. It was found that the catalyst can selectively convert aniline to azoxybenzene with H2O2 as oxidant. The effect of different reaction parameters like reaction temperature, H2O2 to aniline molar ratio, reaction time, and so forth have been studied in detail. An aniline conversion of 78% with azoxybenzene selectivity of 92% can be achieved over this catalyst at 70 °C. The catalyst did not show any leaching up to five reuses, showing the true heterogeneity of the catalyst. However, significant H2O2 decomposition occurs on the catalyst necessitating its usage in five-fold excess.

CuCr2O4 spinel nano.particles with size between 30 and 60 nm were prepared by a hydrothermal synthesis method in the presence of a surfactant, cetyltrimethylammonium bromide (CTAB). It was found that the catalyst is highly active in the selective oxidation of toluene with H2O2 at 75° C. The catalyst was characterized by XRD, ICP-AES, XPS, BET-surface area, SEM, TEM and EXAFS. Factors effecting reaction parameters, such as the substrate to oxidant molar ratio, weight of the catalyst, reaction time, etc., were investigated in detail. The investigation revealed that the size of the catalyst as well as the spinel phase plays a crucial role in the activity by favoring the oxidation of toluene. The reusability of the catalyst was examined by conducting repeat experiments with the same catalyst; it was observed that the catalyst displayed no significant changes in its activity even after 5 reuses. A toluene conversion of 57.5% with 84.4% selectivity towards benzaldehyde was observed after 10 hours over the CuCr2O4 spinel nanoparticles catalyst.

A facile hydrothermal synthesis method is developed to prepare CuCr2O4 spinel nanoparticle catalysts with sizes between 25–50 nm. A detailed characterization of the material was carried out by XRD, ICP-AES, XPS, EXAFS, SEM, TEM, and TGA. XRD revealed the formation of a CuCr2O4 spinel phase and TEM showed the that particles size was 20–50 nm. The catalyst was highly active for the selective oxidation of benzene to phenol with H2O2. The influence of reaction parameters such as temperature, solvent, substrate to oxidant molar ratio, reaction time, etc. were investigated in detail. The reusability of the catalyst was tested by conducting the same experiments with the spent catalyst and it was found that the catalyst did not show any significant activity loss, even after 5 reuses. A benzene conversion of 72.5% with 94% phenol selectivity was achieved over this catalyst at 80 °C. However, significant H2O2 decomposition occurs on the catalyst, necessitating its usage in five-fold excess.

Ni-nanoparticle supported on mesoporous ZSM-5 was prepared by dispersing colloidal Ni-nanoparticle over mesoporous ZSM-5. The resulting material was found thermally stable even at 900 °C and has uniform pore diameter of around 5 nm. The material was characterized by XRD, FE-SEM, TEM, XPS, TPR and N 2 adsorption/desorption. Reforming of methane with CO 2 was performed over Ni supported on mesoporous ZSM-5 at atmospheric pressure. The catalyst shows 96.2% methane conversion at 800 °C with the production of synthetic gas with the H 2 /CO mole ratio of 1:1. Various reaction parameters like temperature, weight hour space velocity (WHSV), Ni loading and time on stream were also studied.

The dielectric relaxation times τjk’s and dipole moments μjk’s of the binary (jk) polar liquid mixture of N,N-dimethyl acetamide (DMA) and acetone (Ac) dissolved in benzene (i) are estimated from the measured real σ′ijk and imaginary σ″ijk parts of complex high frequency conductivity σ*ijk of the solution for different weight fractions wjk’s of 0.0, 0.3, 0.5, 0.7 and 1.0 mole fractions xj of Ac and temperatures (25, 30, 35 and 40°C) respectively under 9.88 GHz electric field. τjk’s are obtained from the ratio of slopes of σ″ijk-wjk and σ′ijk-wjk curves at wjk → 0 as well as linear slope of σ″ijk-σ′ijk curves of the existing method (Murthy et al, 1989) in order to eliminate polarpolar interaction in the latter case. The calculated τ’s are in excellent agreement with the reported τ’s due to Gopalakrishna’s method. μjk’s are also estimated from slopes β’s of total conductivity σijk-wjk curves at wjk → 0 and the values agree well with the reported μ’s from G.K. method. The variation of τjk’s and μjk’s with xj of Ac reveals that solute-solute molecular association occurs within 0.0–0.3xj of Ac beyond which solute-solvent molecular association is predicted. The theoretical dipole moments μtheo’s are calculated from bond angles and bond moments to have exact μ’s only to show the presence of inductive, mesomeric and electromeric effects in the substituent polar groups. The thermodynamic energy parameters are estimated from ln(τjkT) against 1/T linear curve from Eyring’s rate theory to know the molecular dynamics of the system and to establish the fact that the mixture obeys the Debye-Smyth relaxation mechanism.

The role of Internet of Things (IoT) in facilitating connectivity of the wireless sensor network (WSN) to the remote server or cloud over the Internet encourages the formation of a highly complex system with significant potential. This enable the interaction between the physical and virtual sensor clouds resulting in the ability to allow for flexibility within the physical system to adapt with the service requirements. The study of quality of service (QoS) in the domain of WSN-IoT brings forward potentials and challenges, especially due to cost and scalability limitations in physical testbeds and low credibility of simulation results. In this paper, system architecture of a testbed with Adaptive Quality of Service (AQoS) is proposed. AQoS testbed concept provides an avenue for a flexible experimentation system which is capable of reacting to dynamic changes of network conditions. By employing network simulator tools to derive the network performance information based on historical data of a physical testbed, realistic prediction of network performance can be made, and adjustment to the physical network can be proposed. This paper reports the preliminary experiences of implementing an organization for encouraging AQoS. Early stages of testing the organization for absorbing the system behavior and reacting with necessary actuation to the WSN reconfiguration has shown encouraging results.

A halide ion promoted two dimensional silver tungsten-based nanomaterial was synthesized by a facile one-pot synthesis protocol at room temperature. The 2D morphology features high activity and selectivity for the oxidation of a wide range of tertiary N-compounds to their corresponding N-oxides. The morphology of Ag/WO3 materials can be varied by changing the synthesis parameters. The unique 2D plate like morphology of tungsten oxide increases adsorption sites of the support, leading to less sintering and higher dispersion of silver nanoparticles, resulting in significantly enhanced activity for the reaction. The influence of reaction parameters such as temperature, substrate to oxidant molar ratio, reaction time, etc. was investigated in detail. The catalyst was characterized by XRD, XPS, ICP-AES, TGA, FT-IR, UV-vis, Raman, SEM, TEM and STEM. Raman studies further provide mechanistic insight which proves that the formation of peroxo tungsten species is responsible for the N-oxidation reaction. High stability and recyclability of the 2D Ag/WO3 nanoplates are also observed under the investigated conditions.

A three dimensional (3D) hierarchical silver supported tungsten oxide flower-like microsphere catalyst has been fabricated using a cationic surfactant CTAB. It was found that the crystal-splitting mechanism plays a key role in the formation of this flower-like structure. This catalyst was proved to be highly effective in the liquid phase selective oxidation of m-xylene to isophthalic acid.