Experimental investigation of Co and Fe-Doped CuO nanostructured electrode material for remarkable electrochemical performance

The current research work presents a facile and cost–effective co-precipitation method to prepare doped (Co & Fe) CuO and undoped CuO nanostructures without usage of any type of surfactant or capping agents. The structural analysis reveals monoclinic crystal structure of synthesized pure CuO and doped-CuO nanostructures. The effect of different morphologies on the performance of supercapacitors has been found in CV (cyclic voltammetry) and GCD (galvanic charge discharge) investigations. The specific capacitances have been obtained 156 (±5) Fg^?1, 168(±5) Fg^?1 and 186 (±5) Fg^?1 for CuO, Co-doped CuO and Fe-doped CuO electrodes, respectively at scan rate of 5 mVs^?1, while it is found to be 114 (±5) Fg^?1, 136 (±5) Fg^?1 and 170 (±5) Fg^?1 for CuO, Co–CuO and Fe–CuO, respectively at 0.5 Ag^-1 as calculated from the GCD. The super capacitive performance of the Fe–CuO nanorods is mainly attributed to the synergism that evolves between CuO and Fe metal ion. The Fe-doped CuO with its nanorods like morphology provides superior specific capacitance value and excellent cyclic stability among all studied nanostructured electrodes. Consequently, it motivates to the use of Fe-doped CuO nanostructures as electrode material in the next generation energy storage devices.     

Excellent Intrinsic Long-Term Thermal Stability of Co-Evaporated MAPbI3 Solar Cells at 85 °C

Thermal stability is a critical criterion for assessing the long-term stability of perovskite solar cells (PSCs). Here, it is shown that un-encapsulated co-evaporated MAPbI₃ (TE_MAPbI₃) PSCs demonstrate remarkable thermal stability even in an n-i-p structure that employs Spiro-OMeTAD as hole transport material (HTM). TE_MAPbI₃ PSCs maintain over ≈95% and ≈80% of their initial power conversion efficiency (PCE) after 1000 and 3600 h respectively under continuous thermal aging at 85 °C. TE_MAPbI₃ PSCs demonstrate remarkable structural robustness, absence of pinholes, or significant variation in grain sizes, and intact interfaces with the HTM, upon prolonged thermal aging. Here, the main factors driving TE_MAPbI₃ stability are assessed. It is demonstrated that the excellent TE_MAPbI₃ thermal stability is related to the perovskite growth process leading to a compact and almost strain-stress-free film. On the other hand, un-encapsulated PSCs with the same architecture, but incorporating solution-processed MAPbI₃ or Cs_0.05(MA_0.17FA_0.83)_0.95Pb(I_0.83Br_0.17)₃ as active layers, show a complete PCE degradation after 500 h under the same thermal aging condition. These results highlight that the control of the perovskite growth process can substantially enhance the PSCs thermal stability, besides the chemical composition. The TE_MAPbI₃ impressive long-term thermal stability features the potential for field-operating conditions.     

Magnetic field effect on electron emission from plasma

The influence of external magnetic field on the significant parameters of electrons from laser induced plasma (LIP) is investigated. A Q-switched Nd:YAG laser (1064 nm, 9-14 ns, 10 mJ, 1.1 MW) is focused on annealed, 4N pure (99.99%) Silver target (2 × 2 × 0.2 cm³) for production of plasma under vacuum ∼10⁻³ torr. Temperature, density and energy measurements for electrons were made by self fabricated Langmuir probe both in the absence and presence of external magnetic field (∼1.2 T) at different positions. The signals are recorded on 200 MHz UTT 2202 digital storage oscilloscope. The results thus obtained reveal decrease in electron temperature, energy and density in presence of external magnetic field. Confinement of plasma is also observed.     

Options for support tower design of a sensitive equipment under ambient vibrations

This paper describes the options and methodology adopted for the design of an 18‐m high support tower for a vibration sensitive optical telescope. The telescope was to be housed inside an existing building that provided shielding from atmospheric wind and thermal variations. However, proper functioning of the telescope was dependent on the support tower's structural configuration and stiffness to limit angular distortion of the telescope platform to less than 2 µ radians or 0·4 arc‐sec. This level of sensitivity required investigation of support tower response under ambient vibrations resulting from normal operation of the existing facility. The measured peak ambient vibration acceleration ranged from 0·04 m/s/s to 0·27 m/s/s for various recorded events. Two options for the tower were investigated viz. steel braced frame and concrete shaft. The effect of soil structure interaction (SSI) was also examined. It was concluded that the concrete tower option provided the desired performance for both fixed base and SSI cases. On the other hand, the steel tower performed well for the fixed base case but its performance was close to the threshold when SSI was also considered. Effect of soil properties variation on SSI was also examined for both tower options and was found to be relatively insignificant. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis,structure and calculated NLO properties of [(n-Bu)2Sn-μ-O-μ-OH-Sn(n-Bu)2(CH3CO2)]2 and its putative derivatives

Title compound[(n-Bu)₂Sn-μ-O-μ-OH-Sn(n-Bu)₂(CH₃CO₂)]₂ was obtained accidentally by the reaction of n-Bu₂SnCl₂ with the metalloligand K₂[Ni(CDC)₂] in ethanol - water mixture while synthesizing a heterobimetallic complex [n-Bu₂Sn Ni(CDC)₂]. This has been characterized by micro analysis, UV–Vis, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy and the single crystal X-ray. The complex forms an interesting supramolecular architecture via (acetate)O?HO hydrogen bonding interactions which generates hydrophobic “pseudo-cage”. The electronic absorption bands of the title complex were assigned with the help of the time dependent density functional theory (TD-DFT) calculations. Density functional theory (DFT) calculations have been performed at the optimized molecular geometry of some of its putative derivatives e. g. trans p-amino cinnamic acid derivative 2; trans p-amino cinnamic acid and trans p-nitro cinnamic acid derivative 3; trans p-amino cinnamic acid and trans p-(N,N dimethylamino) cinnamic acid derivative 4. The first static hyperpolarizability (β) of the title compound and its derivatives were calculated with double numerical differentiation of total energies. The derivatives 3 and 4 showed three times and five times enhancement in the non-linear optical (NLO) responses than the standard p-nitroaniline (pNA).     

INTERNET‐BASED REAL‐TIME CONTROL ARCHITECTURES WITH TIME‐DELAY/PACKET‐LOSS COMPENSATION

The main objective of this paper is to demonstrate the feasibility of Internet‐based real‐time control. A novel client/server‐based architecture for Internet‐based supervisory control with a Common Gateway Interface/Hyper Text Markup Language (CGI/HTML) interface is presented. A real‐time operating environment was established for closed‐loop control over Ethernet. We conceived of an autoregressive (AR) prediction scheme and a novel compensation algorithm to compensate for network‐induced time delays and data‐packet losses simultaneously. We constructed an open‐loop unstable ball magnetic‐levitation (maglev) setup as a test bed to validate the two proposed control architectures. Experimental results proved the feasibility of Internet‐based real‐time control and verified the effectiveness of the proposed time‐delay/packet‐loss compensation algorithm in networked feedback control systems.     

Effects of fiber surface grafting by functionalized carbon nanotubes on the interfacial durability during cryogenic testing and conditioning of CFRP composites

Carbon fiber reinforced epoxy (CE) composite is ideal for a cryogenic fuel storage tank in space applications due to its unmatched specific strength and modulus. In this article, inter-laminar shear strength (ILSS) of carbon fiber/epoxy (CE) composite is shown to be considerably improved by engineering the interface with carboxyl functionalized multi-walled carbon nanotube (FCNT) using electrophoretic deposition technique. FCNT deposited fibers from different bath concentrations (0.3, 0.5, and 1.0 g/L) were used to fabricate the laminates, which were then tested at room (30°C) and in-situ liquid nitrogen (LN) (−196°C) temperature as well as conditioning for different time durations (0.25, 0.5, 1, 6, and 12 h) followed by immediate RT testing to study the applicability of these engineered materials at the cryogenic environment. A maximum increment in ILSS was noticed at bath concentration of 0.5 g/L, which was ~21% and ~ 17% higher than neat composite at 30°C and − 196°C, respectively. Short-term LN conditioning was found to be detrimental due to developed cryogenic shock, which was further found to be compensated by cryogenic interfacial clamping upon long-term exposure.     

3D‐Printing of High‐κ Thiol‐Ene Resins with Spiro‐Orthoesters as Anti‐Shrinkage Additive

Tri(ethylene glycol) divinyl ether and the spiro‐orthoester 2‐((allyloxy)methy)‐1,4,6‐trioxospiro[4.4]nonane can be formulated in different ratios and crosslinked by thiol‐ene reactions. The spiro‐orthoester is used as anti‐shrinkage additive, enabling shrinkage reduction of up to 39%. Addition of a radical photoinitiator for the thiol‐ene reaction and a cationic photoinitiator for the double ring‐opening of the spiro‐orthoester enables dual‐curing for application in 3D‐printing. The formulation free of the spiro‐orthoester shows gelation during the printing process and, correspondingly, low resolution. The formulations containing the spiro‐orthoester exhibit higher resolutions in the range of 50 µm. The resins containing mixtures of tri(ethylene glycol) divinyl ether and the spiro‐orthoester show permittivities as high as 10⁴. The dielectric loss factor of the resins is in the range of 0.5–7.6, and the conductivity in the range of 1.3?10^?11 to 2.0?10^?11 S cm^?1. These high‐κ materials can be 3D‐printed by digital light processing for the next generation of electronic materials.     

Efficacious Doxorubicin Delivery Using Glutathione-Responsive Hollow Non-phospholipid Vesicles Bearing Lipoyl Cholesterols

In this study, we developed redox-sensitive vesicles using synthesised lipoyl cholesterol derivatives, a non-ionic surfactant and an optimum level of free cholesterol. Interestingly, concentration-dependent self-assembly was observed by scanning electron microscopy, wherein vesicles manifested as hollow spherical (at 0.15 mm ) and triangular (0.50 mm ). The redoxresponsive characteristics of the vesicles was probed in the presence of dithiothreitol; they underwent a clear increase in size as observed by dynamic light scattering measurements. These vesicles could easily encapsulate an anticancer drug, doxorubicin, and were observed to be stable in the presence of serum. They showed substantial release of the drug in response to biologically relevant stimulus, that is, glutathione. A toxicity assessment on HeLa and HepG2 cancer cells demonstrated activities of the drug-loaded vesicles comparable to that of free drug, whereas significantly enhanced toxicity and apoptotic induction were observed against drug-resistant HeLa cells, which was determined by studying the cellular internalisation of doxorubicin.     

Biofilter in water and wastewater treatment

Biofilter is one of the most important separation processes that can be employed to remove organic pollutants from air, water, and wastewater. Even though, it has been used over a century, it is still difficult to explain theoretically all the biological processes occurring in a biofilter. In this paper, the fundamental of biological processes involved in the biofilter is critically reviewed together with the mathematical modeling approach. The important operating and design parameters are discussed in detail with the typical values used for different applications. The most important parameter which governs this process is the biomass attached to the medium. The relative merits of different methods adopted in the measurement of the biomass are discussed. The laboratory-and full-scale applications of the biofilter in water and wastewater treatment are also presented. Their performances in terms of specific pollutant removal are highlighted.