Competing risk theory approach to the nature of the outcome of conception

An attempt has been made to obtain the probabilities of pregnancy termination by live birth, still birth and abortion, in any particular order, assuming that the termination of pregnancy is associated with three competing ‘risks’, i.e. live birth, still birth and abortion, which need not necessarily operate at the same point of time. A probability model has been constructed to obtain the conditional probability of live birth/still birth/abortion given that the previous pregnancy has been terminated by a particular one of the three. The correlation coefficient between the outcomes of two particular consecutive pregnancy terminations, viz. live birth and reproductive wastage (which includes both abortion and still birth), has also been obtained. Given data pertaining to sample correlation coefficients between the nature of consecutive orders of the outcomes of conception from first to sixth, an exercise has been undertaken to estimate parameters relating to the ‘hazard’ rates of live births, still birth and abortion. The exercise further enables one to test the well-known demographic hypothesis that reproductive wastages follow each other in succession over consecutive orders of the outcomes of conception.     

Combustion synthesis of graphene and ultracapacitor performance

Graphene sheets are synthesized by a simple method starting from graphitic oxide as a precursor. Reaction of graphitic oxide at 250 °C with a combustion mixture of urea and ammonium nitrate results in the formation of thin graphene sheets. Graphene formation is characterized by XRD, TGA, XPS and TEM. Graphene materials synthesized by this method are investigated as an ultracapacitor material. Specific capacitance values of about 70 F/g are obtained at a current density of 100 mA/g by using KOH as an electrolyte.     

COVID-19: Review on Its Etiology,Pathogenesis, and Existence in Humans

The world is facing a new healthcare crisis with the rise and spread of novel coronavirus since December 2019. Also known as Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2), the disease associated with SARSCoV-2 is even called COVID-19. The infection is said to have originated from the bat community and transmitted to humans through an intermediate host (yet unknown) in Wuhan, in the Hubei region of China. COVID-19 is having a pulverizing impact on the scientific community. As of August 13, 2020, the number of confirmed cases had reached up to 20,439,814 and the death toll to 744,385, affecting more than 188 territories across the globe. In these difficult times, the world is looking towards research and clinical work from different scientific communities to lead the way to a solution to the issue. In this review, we are focusing on COVID-19 emergence, pathogenicity, and existence in humans, as well as the SARS-CoV-2 infection mechanism and its similarities to previous coronavirus strains.     

Thermal Performance of ‘Still-on-Roof’ System with Water Flowing through the Roof

In the present communication, authors propose and analyze a system which consists of a solar still kept over the roof of a room, and a water-flowing arrangement in the roof. The performance of the system is studied under two modes of heat extraction, viz., constant flow rate, and constant collection temperature, An analytical model has been developed which provides explicit expressions for various performance parameters of the system. The model is useful in evaluating the system performance under the variation of different parameters. In order to appreciate the proposed configuration, numerical calculations are carried out corresponding to the typical climate of Delhi, India. The calculations show that the system is effective in reducing the heat flux entering the room and provides warm water in addition to the distilled water.     

Pyrolysis of petroleum asphaltenes from different geological origins and use of methylnaphthalenes and methylphenanthrenes as maturity indicators for asphaltenes

Asphaltenes separated from two different crude oils from upper Assam, India, having different geological origins, viz. DK (eocene) and JN (oligocene–miocene) were pyrolysed at 600 °C and the products were analysed by gas chromatography–mass spectrometry (GC/MS) especially for the generated alkylnaphthalenes and alkylphenanthrenes. Both the asphaltenes produce aliphatic as well as aromatic compound classes. Alkylnaphthalenes and alkylphenanthrenes were identified by using reference chromatograms and literature data and the distributions used to assess thermal maturity of the asphaltenes. The ratios of β -substituted to α -substituted isomers of both alkylnaphthalenes and alkylphenanthrenes revealed higher maturity of the JN asphaltenes than the DK asphaltenes. For both the asphaltenes, the abundance of 1-methylphenanthrene dominates over that of 9-methylphenanthrene showing the terrestrial nature of the organic matter.     

Aged rare earth doped silicates as optoelectronic material

Samples of various concentrations were prepared and kept unsintered for a period of three years to study the consistency of composition prepared and structural evolution of glass. The expanded peaks in the Raman spectra arise due to thermal agitation, and a Boltzmann type of distribution was expected in the silicate gels. The behavior of the gels during the dehydroxylation and dehydration is conditioned by its microstructure, which depends upon the physical conditions, I.e., pH, and drying conditions.     

Synthesis and characterization of CuO nanoparticles using strong base electrolyte through electrochemical discharge process

In the present study, cupric oxide (CuO) nanoparticles were synthesized by electrochemical discharge process using strong base electrolytes. The experiments were carried out separately using NaOH and KOH electrolytes. The mass output rate and the crystal size were obtained with variation of the rotation speed of magnetic stirrer for both types of electrolytes. The mass output rate of CuO nanoparticles increased with the increase in the speed of rotation, and, after an optimum speed, it started decreasing. However, the size of the particles reduced with the increase of the rotation speed. The crystal plane of the obtained CuO nanoparticles was similar for both the electrolytes whereas the yield of nanoparticles was higher in KOH as compared with NaOH under the same experiment conditions. In this set of experiments, the maximum output rates obtained were 21.66 mg h^?1 for NaOH and 24.66 mg h^?1 for KOH at 200 rpm for a single discharge arrangement. The average crystal size of CuO particles obtained was in the range of 13–18 nm for KOH electrolyte and 15–20 nm for NaOH electrolyte. Scanning electron microscopy images revealed that flower-like and caddice clew-shaped CuO nanocrystalline particles were synthesized by the electrochemical discharge process. Fourier transform infrared spectrum showed that the CuO nanoparticles have a pure and monolithic phase. UV–vis–NIR spectroscopy was used to monitor oxidation course of Cu → CuO and the band gap energy was measured as 2 and 2.6 eV for CuO nanoparticle synthesized in NaOH and KOH solutions, respectively.