Synthesis,characterization, thermal,electrical and electrochemical studies of oligo nitrobenzimidazoles and their p–n diode applications

Three novel nitro oligobenzimidazoles, oligo-2-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP2), oligo-3-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP3) and oligo-4-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP4) were synthesized by oxidative polycondensation of benzimidazole monomers with NaOCl in aqueous alkaline medium. The structure of the monomers and oligomers were confirmed by FT-IR, UV–Vis, ¹H and ¹³C NMR spectroscopic techniques. The monomer BINP2 and its oligomer are showing dual emission through excited state intramolecular proton transfer process. The band gap values of monomers and oligomers were calculated from both UV–Vis spectroscopic and cyclic voltammetric data. Theoretical band gap values of monomers obtained from DFT were compared with experimentally calculated band gap values. The electrical conductivity of I₂ doped and undoped oligomers were measured using two point probe technique and are showing good correlation with the charge densities on imidazole nitrogen obtained from Huckel method. The conductivity of oligomers increases with increase in iodine vapour contact time up to 144 h. The variation of dielectric properties of oligomers has been investigated at different frequency and temperature. Among the oligomers, OBINP3 is having greater thermal stability as evidenced by its high carbine residue of around 65% at 600 °C in thermogravimetric analysis.     

Adoption of Rainwater Harvesting: a Dual-factor Approach by Integrating Theory of Planned Behaviour and Norm Activation Model

The objective of the study is to identify the factors that lead to the adoption of rainwater harvesting in enabling sustainable ground water. The Theory of Planned Behavior and Norm Activation Model has been adopted. The sample consists of 400 participants who were either constructing and likely to construct houses have been considered for the study. Structural Equation Modelling was used to analyze the data. The study results exhibited the adoption of rainwater harvesting, and the moderation effect of intention to acquire rainwater harvesting knowledge on the relationship between environmental concern; environmental responsibility and rainwater harvesting. Based on the results, significant theoretical and practical implications have been made.

     

A film model analysis of non-equimolar distillation of multicomponent mixtures

Differences in the molar heats of vaporizations of component species in a multicomponent mixture lead to non-equimolar mass transfers during distillati     

Active noise control using a distributed mode flat panel loudspeaker

A flat panel distributed mode loudspeaker (DML) has many advantages over traditional cone speakers in terms of its weight, size, and durability. However, its frequency response is uneven and complex, thus bringing its suitability for active noise control (ANC) under question. This paper presents experimental results demonstrating the effective use of panel DML speakers in an ANC application. Both feedback and feedforward control techniques are considered. Effective feedback control with a flat panel speaker could open up a whole range of new noise control applications and has many advantages over feedforward control. The paper develops a new control algorithm to attenuate tonal noise of a known frequency by feedback control. However, due to the uneven response of the speakers, feedback control is found to be only moderately effective even for this narrow-band application. Feedforward control proves to be most capable for the flat panel speaker. Using feedforward control, the sound pressure level can be significantly reduced in close proximity to an error microphone. The paper demonstrates an interesting application of the flat panel in which the panel is placed in the path of sound and effectively used to block sound transmission using feedforward control. This is a new approach to active noise control enabled by the use of flat panels and can be used to prevent sound from entering into an enclosure in the first place rather than the traditional approach of attempting to cancel sound after it enters the enclosure.     

Experimental study and hydrodynamic modeling of countercurrent liquid–solid system with batch liquid

It is known that a transient effluent outlet concentration is obtained with a batch of adsorbent solids in any operation. A preferred steady state outlet concentration can be achieved with a continuous flow of solids. In the present work, information on pressure profiles, the total pressure drop across the column and holdup of solids are experimentally obtained for various solid flow rates, particle sizes and densities in a countercurrent liquid–solid system. These experimental results are compared with the prediction obtained using a phenomenological model containing continuity and momentum balance equations. The dominant drag force term was expressed in terms of various drag equations. The drag expression developed by Foscolo et al. (1983 Foscolo, P. U., Gibilaro, L. G., and Waldram, S. P. (1983). A unified model for particulate expansion of fluidized beds and flow in fixed porous media, Chem. Eng. Sci., 38(8), 1251–1260.[Crossref], [Web of Science ®] , [Google Scholar]) could predict the axial profiles of pressure drop and holdup, and the effect of various parameters on total pressure drop and solid holdup most satisfactorily.     

Debris slides of Varandh Ghat, west coast of India

 On 28 June 1994 when 240 mm of rainfall occurred, a huge debris slide took place at Parmachi village in the Varandh Ghat of the Konkan district on the west coast of India. The debris slide resulted in extensive damage to property and killed 20 people in addition to numerous animals. The slide is considered to have occurred due to the development of hydrostatic pressure at the base of colluvial material, such that slope failure took place at the rock/soil interface. In view of the significance of such slides to settlements and highways, it is proposed that a warning system is developed based on a rainfall threshold of 170 mm in a 24-hour period. Received: 21 February 1997 · Accepted: 5 January 1998     

A framework to practical predictive maintenance modeling for multi-state systems

A simple practical framework for predictive maintenance (PdM)-based scheduling of multi-state systems (MSS) is developed. The maintenance schedules are derived from a system-perspective using the failure times of the overall system as estimated from its performance degradation trends.

The system analyzed in this work is a flow transmission water pipe system. The various factors influencing PdM-based scheduling are identified and their impact on the system reliability and performance are quantitatively studied. The estimated times to replacement of the MSS may also be derived from the developed model.

The results of the model simulation demonstrate the significant impact of maintenance quality and the criteria for the call for maintenance (user demand) on the system reliability and mean performance characteristics. A slight improvement in maintenance quality is found to postpone the system replacement time by manifold. The consistency in the quality of maintenance work with minimal variance is also identified as a very important factor that enhances the system's future operational and downtime event predictability.

The studies also reveal that in order to reduce the frequency of maintenance actions, it is necessary to lower the minimum user demand from the system if possible, ensuring at the same time that the system still performs its intended function effectively.

The model proposed can be utilized to implement a PdM program in the industry with a few modifications to suit the individual industrial systems’ needs.     

Nanoscale domain switching behaviour in polycrystalline ferroelectric thin films

We report on the nanoscale domain switching behaviour in polycrystalline tetragonal perovskite lead zirconate titanate (PZT) ferroelectric thin films investigated via piezoresponse force microscopy (PFM). Local domain structures were imaged as a function of varying biasing conditions and spatial location of the tip within 50-100?nm sized grains. Nanoscale piezoresponse images provided direct visual evidence of the complex interplay between electrical and mechanical fields in a polycrystalline system, which causes effects such as correlated switching between the grain of interest and neighbouring grains, ferroelastic domain switching, inhomogeneous piezostrain profiles and domain pinning on very minute length scales. Detailed investigations on mechanisms which induce such domain behaviour are presented.     

Astragaloside IV Attenuates Ocular Hypertension in a Mouse Model of TGFβ2 Induced Primary Open Angle Glaucoma

Elevated intraocular pressure (IOP) is a major risk factor in developing primary open angle glaucoma (POAG), which is the most common form of glaucoma. Transforming growth factor-beta 2 (TGFβ2) is a pro-fibrotic cytokine that plays an important role in POAG pathogenesis. TGFβ2 induced extracellular matrix (ECM) production, deposition and endoplasmic reticulum (ER) stress in the trabecular meshwork (TM) contribute to increased aqueous humor (AH) outflow resistance and IOP elevation. Drugs which alter the glaucomatous fibrotic changes and ER stress in the TM may be effective in reducing ocular hypertension. Astragaloside IV (AS.IV), a novel saponin isolated from the roots of Astragalus membranaceus, has demonstrated antifibrotic and ER stress lowering effects in various tissues during disease conditions. However, the effect of AS.IV on glaucomatous TM fibrosis, ER stress and ocular hypertension has not been studied. Primary human TM cells treated with AS.IV decreased TGFβ2 induced ECM (FN, Col-I) deposition and ER stress (KDEL, ATF4 and CHOP). Moreover, AS.IV treatment reduced TGFβ2 induced NF-κB activation and αSMA expression in TM cells. We found that AS.IV treatment significantly increased levels of matrix metalloproteases (MMP9 and MMP2) and MMP2 enzymatic activity, indicating that the antifibrotic effects of AS.IV are mediated via inhibition of NF-κB and activation of MMPs. AS.IV treatment also reduced ER stress in TM3 cells stably expressing mutant myocilin. Interestingly, the topical ocular AS.IV eye drops (1 mM) significantly decreased TGFβ2 induced ocular hypertension in mice, and this was associated with a decrease in FN, Col-1 (ECM), KDEL (ER stress) and αSMA in mouse TM tissues. Taken together, the results suggest that AS.IV prevents TGFβ2 induced ocular hypertension by modulating ECM deposition and ER stress in the TM.