Flame Retardance and Smoke Suppression of Poly(vinyl chloride) Using Multicomponent Systems

Metal-based organic complexes (MBO) are a class of FRSS additives that comprise a transition metal and an organic ligand that cleaves at an elevated temperature thereby releasing the metal in a reactive state. They help in the formation of char and thus act as an effective smoke suppressant. Use of MBO complexes as flame retardant smoke suppressants, phosphate ester as a flame retardant and active filler as endothermic material is reported here as multicomponent FRSS systems. MBOs used in the present study are the chelates of pentanediono. They were used alone as well as in combination with aluminum trihydrate (ATH) as filler were used to impart flame retardancy and smoke suppression to poly vinylchloride. Their performance was measured in terms of flammability, smoke generation, char formation and evolution of combustion gases. MBOs of molybdenum and chromium were found to be very efficient flame retardant smoke suppressants.     

A preliminary study of wind–solar hybrid systems potential in Jammu and Kashmir

ABSTRACT

This paper deals with the study of wind–solar hybrid systems in the region of Jammu and Kashmir. Due to scarcity of less renewable energy resources in the J&K region, National Institute of Wind Energy, Chennai had installed different wind monitoring stations to measure the wind data at different locations. The survey reveals that four districts (LEH, KARGIL, POONCH and REASI) are suitable for small wind–solar hybrid systems. BIDDA (REASI) and CHUSHUL (LEH) are the two sites for small wind farm development due to the highest wind speed (more than 7?m/s) and power density (more than 400?W/m²) at 100?m agl.     

Probable risk estimation due to reservoir induced seismicity at Jamrani dam Project,Kumaon Himalaya,India

A lake of about 4.5 sq. km. spread having 208 millions cubic meter storage capacity is proposed to be created in outer Himalaya for meeting irrigation, industrial and domestic supplies, downstream of 130 m high Jamrani dam. The bedrock around the lake consists of alternate bands of sandstone, clayshale and siltstone of siwalik Formations, (Middle Miocene to Pliocene) and thrust mass of Amritpur granite. The tectonic plane (Main Boundary fault) lies about 3.5 km upstream of the dam. The problem of Reservoir Induced Seismicity (RIS) though complex and unpredictable has been studied the world over at several major dam projects which provide some information on the factors responsible for RIS such as (i) geo-tectonic, setting (ii) pore-water pressure (iii) background seismicity and (iv) reservoir water load. Any one or the combination of these factors play an important role in inducing, earthquakes. The subject of RIS has been discussed in the light of the analysis of the seismic risk related to Jamrani reservoir in its geo-tectonic setting.     

Studies of interaction of amines with TOPO/TOP capped CdSe quantum dots: Role of crystallite size and oxidation potential

This work reports the interaction of aliphatic (triethyl amine, butyl amine) and aromatic amines (PPD, aniline) with CdSe quantum dots of varied sizes. The emission properties and lifetime values of CdSe quantum dots were found to be dependent on the oxidation potential of amines and crystallite sizes. Smaller CdSe quantum dots (size 5 nm) ensure better surface coverage of amines and hence higher quenching efficiency of amines could be realized as compared to larger CdSe quantum dots (size 14 nm). Heterogeneous quenching of amines due to the presence of accessible and inaccessible set of CdSe fluorophores is indicated. PPD owing to its lowest oxidation potential (0.26 V) has been found to have higher quenching efficiency as compared to other amines TEA and aniline having oxidation potentials 0.66 and >1.0 V, respectively. Butyl amine on the other hand, plays a dual role: its post-addition acts as a quencher for smaller and enhances emission for larger CdSe quantum dots, respectively. The beneficial effect of butyl amine in enhancing emission intensity could be attributed to enhance capping effect and better passivation of surface-traps.     

Adsorption of Cr(VI) from aqueous solutions by spent activated clay

Adsorption of Cr(VI) onto spent activated clay (SAC), a waste produced from an edible oil refinery company, was investigated for its beneficial use in wastewater treatment. After pressure steam treatment, SAC was used as an adsorbent. The adsorption kinetic data were analyzed and fitted well in a pseudo-first-order equation and the rate of removal was found to speed up with decreasing pH and increasing temperature. Activation energy for the adsorption process was found to be 4.01–5.47 kcal/K mol. The Langmuir adsorption isotherm was used to fit the equilibrium data and the effect of pH, temperature and ionic strength were studied. The maximum adsorption capacities for Cr(VI) ranged from 0.743 to 1.422 mg/g for temperature between 4 and 40 °C under a condition of pH 2.0. The studies conducted show the process of Cr(VI) removal to be spontaneous at high temperature and endothermic in nature. From the waste utilization and environment point of view, the work carried out is important and useful. Results obtained can serve as baseline data for designing a treatment process using this low-cost adsorbent for the treatment of wastewater rich in Cr(VI).     

Elastic liposomal formulation for sustained delivery of antimigraine drug: in vitro characterization and biological evaluation

The aim of this study was to prepare and characterize a topical formulation for sustained delivery of rizatriptan. Elastic liposomal formulation of rizatriptan was prepared and characterized for different characteristics by evaluating in vitro and in vivo parameters. The in vivo performance of optimized formulation was evaluated for antimigraine activity in mice using morphine withdrawal-induced hyperalgesia. The in vitro skin permeation study across rat skin suggested carrier-mediated transdermal permeation for different elastic liposomal formulation to range between 18.1 +/- 0.6 and 42.7 +/- 2.3 microg/h/cm(2), which was approximately 8-19 times higher than that obtained using drug solution. The amount of drug deposited was 10-fold higher for elastic liposome (39.9 +/- 3.2%) than using drug solution (3.8 +/- 1%); similarly the biological activity of optimized elastic liposome formulation was found to be threefold higher than the drug solution. On the basis of the results, it can be concluded that the elastic liposomal formulation provided sustained action of rizatriptan due to depot formation in the deeper layer of skin.     

A new method of chaining carbon nanofibers in epoxy

In this paper, a new and innovative process for assembling chains of carbon nanofibers (CNFs) in epoxy, uniquely different from those generally used for chaining particles in a liquid medium, is presented. Chains of aligned CNFs are assembled in a region rich in CNFs and extended into regions where there are no CNFs. A physical explanation of the process is provided based on the conductive nature of the CNFs. By contacting the chains with the electrodes, the process of chain growth is expedited and well-ordered parallel chains with equal?spacing are grown over distances of 2?cm.     

Quantum dot microdrop laser

We report single-mode and multimode lasing from isolated spherical liquid microcavities containing CdSe/ZnS nanocrystal quantum dots. Lasing is observed at densities more than 2 orders of magnitude lower than previously demonstrated or theoretically predicted, assuming a uniform nanocrystal quantum dot distribution. Charged droplets, between 10 and 40 microm in size, are electrodynamically levitated and optically pumped. Substantial laser signals at low thresholds are measured from the directional emission normal to the pump beam, owing to the high Q cavity modes.     

Thickness dependent structural, electronic, and optical properties of Ge nanostructures

In the present paper, we have investigated structural, optical as well as electronic properties of electron beam evaporated Ge thin films having layer thicknesses ranging from ultra-thin (5 nm) to thick (200 nm). The Raman spectra show that all peaks are shifted towards lower wave number as compared to their bulk counterparts and are considered as a signature of nanostructure formation and quantum confinement effect. The Raman line exhibits transformation from nanocrystalline to microcrystalline phase with a reduction in blue shift of peak position with increase in Ge film thickness (>5 nm). Similarly, the optical absorption spectra corresponding to these films also show reduction in blue shift effect, although Ge 5 nm film shows the absorption behaviour quite different from higher thickness films. The corresponding band gap values obtained from absorption measurements are much larger than bulk Ge and are mainly attributed to the effect of quantum confinement as expected for small size particles calculated from GIXRD patterns. AFM data in each case are correlated and discussed with structural as well as optical results to support the effect of growth morphology on the above-mentioned observations. The results are further supported by photoelectron spectroscopy (PES), photoluminescence (PL) and resistivity measurements and are interpreted in terms of crystallinity and quantum confinement effect.     

On a Non-linear Electronic Circuit Filtering

The stochastic versions of non-linear dynamic circuits are formalized using non-linear stochastic differential equations. Stochastic differential equations (SDEs) are exploited to analyse dynamical systems in noisy environments. A potential application of the SDEs can be regarded as ‘stochastic processes in electronic circuits’. The noisy sampling mixer, a component of digital wireless communications, is an appealing and standard case from the dynamical systems’ viewpoint. It assumes the structure of a non-linear SDE, and its linearized version becomes time-varying bilinear SDE. This paper derives the filtering equations for the noisy non-linear sampling mixer circuit utilizing the filtering density evolution equation. The filtering model for the stochastic problem of concern here comprises the following: (1) a non-linear SDE describing the noisy sampling mixer and (2) a non-linear noisy observation equation. It is interesting to note that the filtered estimate accounts for observations. On the other hand, the predicted estimate does not account for the observation terms in evolution equations. As a result of this, the filtered estimate confirms the greater accuracy of estimated state trajectory in contrast to the predicted trajectory. The filtering equation of this paper can be further utilized for control of the noisy sampling mixer, where the observations are available.