4′-(2,4-Dichloro­phen­yl)-1,1′-dimethyl­piperidine-3-spiro-3′-pyrrolidine-2′-spiro-3′′-indoline-4,2′′-dione

In the title compound, C23H23Cl2N3O2, the pyrroline ring adopts an envelope conformation and the piperidinone ring assumes a slightly twisted chair form. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate an R 2 8 graph-set motif and a short Cl⋯Cl contact of 3.478 (1) Å occurs

Arctic warming by abundant fine sea salt aerosols from blowing snow

The Arctic warms nearly four times faster than the global average, and aerosols play an increasingly important role in Arctic climate change. In the Arctic, sea salt is a major aerosol component in terms of mass concentration during winter and spring. However, the mechanisms of sea salt aerosol production remain unclear. Sea salt aerosols are typically thought to be relatively large in size but low in number concentration, implying that their influence on cloud condensation nuclei population and cloud properties is generally minor. Here we present observational evidence of abundant sea salt aerosol production from blowing snow in the central Arctic. Blowing snow was observed more than 20% of the time from November to April. The sublimation of blowing snow generates high concentrations of fine-mode sea salt aerosol (diameter below 300 nm), enhancing cloud condensation nuclei concentrations up to tenfold above background levels. Using a global chemical transport model, we estimate that from November to April north of 70° N, sea salt aerosol produced from blowing snow accounts for about 27.6% of the total particle number, and the sea salt aerosol increases the longwave emissivity of clouds, leading to a calculated surface warming of +2.30 W m−2 under cloudy sky conditions

Rapid growth of new atmospheric particles by nitric acid and ammonia condensation

New-particle formation is a major contributor to urban smog$^{1,2}$, but how it occurs in cities is often puzzling$^{3}$. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below −15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid–base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms$^{4,5}$

Activated Carbon - Mn<sub>3</sub>O<sub>4</sub> Nanocomposites – Synthesis and Magnetic Studies

Keywords: Activated carbon; Nanocomposites; Mn3O4; Saturation magnetization Abstract: Activated carbon-Mn3O4 nanocomposites have been prepared by in situ decomposition of metal carboxylates into activated carbon matrix using acetate and benzoate of manganese as precursor for metal oxide. The morphology and size of the Mn3O4 particles inserted into activated carbon matrix have been investigated by IR, XRD, Scanning electron microscope and Transmission electron microscope. The magnetic nature of composites has been investigated by Vibrating Sample Magnetometer.</jats:p

EXPERIMENTAL AND PERFORMANCE ANALYSIS OF SOLAR REFRIGERATION SYSTEM USING NANO FLUIDS

In today’s world refrigeration systems play a vital role to fulfil the human needs. A continuous research is being carried out by many researchers in order to improve the performance of these systems. Presently used, vapour compression refrigeration system does not work efficiently due to shortage of electric power. This study covers a broad overview of solar photovoltaic technology, which uses easily available solar energy for refrigeration purpose. It includes a motor, a compressor, an inverter and battery, a photovoltaic controller and panels. This can be done by converting solar energy in to electricity by means of photovoltaic devices, which can be utilized by the electric motor to drive vapour compression refrigeration system. The main objective of the study is managing the shortage of electric power, in living environments by using a cooling system coupled to a solar installation. In this solar refrigeration system, when conventional refrigerants like (R22, HFCR134a, R600, etc.) are used it leads to low thermal conductivity, heat transfer rate and COP level and some of the other impacts are acid rain, melting of glaciers, sea level raising, health impacts, atmospheric pollution, ozone depletion, which is very hazardous to the environment. To avoid these threats, one of the ways is to use nanofluids which are not harmful to the environment. The usage of nanofluids results in high thermal conductivity, heat transfer rate and give better COP level. The following three nanofluids Al2o3, Zro2, Cu2o have been already used in the refrigeration system. Some of the properties of given nanofluids will be changed to innovate new nanofluids. The innovated nanofluids will be used in refrigeration system and the same will be compared with other nanofluids like R22, R134a, R290, and R600a. Even though Al2o3, Zro2, Cu2o gives good results, the new nanofluids have been innovated for better results.</jats:p