A procedure for quantitative 13c-n.m.r. application to the characterisation of the naphtha fraction of petroleum crude

A method for optimising the conditions for the quantitative ¹³C-n.m.r. measurement is suggested and has been applied to the compositional studies of naphtha fractions (50–100°C and 100–150°C) of Darius crude oil. The novelty of the method is that we can pre-estimate the pulse repetition time for unknown samples. It has been shown that the various compositional parameters thus obtained are in satisfactory agreement with those obtained from the elemental analysis, fluorescent indicator adsorption (FIA) and ¹H-n.m.r. spectrometry.     

Burden of organochlorine pesticides in blood and its effect on thyroid hormones in women

Man has utilized a wide variety of pesticides to combat the crop pests and vectors of human diseases. However, in this process, he has overlooked the darker side of these noxious chemicals, the concentrations of which have reached the environment and pose serious threats, such as mutagenesis, teratogenesis, carcinogenesis and endocrine dysfunction in various components of the ecosystem. The present study was planned to assess the burden of organochlorine pesticides and their influence on thyroid function in women. The study included a total of 123 women from Jaipur City who visited the Thyroid clinic in SMS Medical College and Hospital. One hundred women showed normal thyroid hormone levels while the remaining 23 women had depleted T4 and high TSH levels. The qualitative and quantitative estimation of organochlorine pesticides was carried out by gas chromatography. Out of the analyzed pesticides, the concentration of p,p'-DDT and its metabolites was higher in all the subjects, but dieldrin was found to be significantly high in the hypothyroid women. The correlation analysis for dieldrin and depleted T4 levels in hypothyroid women elicited an inverse relationship between them.     

Robust optimization of Random Early Detection

Random Early Detection (RED) is the most widely used Adaptive Queue Management (AQM) mechanism in the internet. Although RED shows better performance than its predecessor, DropTail, its performance is highly sensitive to parameter settings. Under non-optimum parameter settings, the performance degrades and quickly approaches that of DropTail gateways. As the network conditions change dynamically and since the optimum parameter settings depend on these, the RED parameters also need to be optimized and updated dynamically. Since the interaction between RED and TCP is not well understood as analytical solutions cannot be obtained, stochastic approximation based parameter optimization is proposed as an alternative. However, simulation based approaches may yield a sub-optimal solution since for these to work, the network needs to be accurately simulated which is, however, infeasible with today’s internet. In this paper, we present an optimization technique for optimizing RED parameters that makes use of direct measurements in the network. We develop a robust two-timescale simultaneous perturbation stochastic approximation algorithm with deterministic perturbation sequences for optimization of RED parameters. A proof of convergence of this algorithm is provided. Network simulations, using direct implementation of the algorithm over RED routers, are carried out to validate the proposed approach. The algorithm presented here is found to show better performance as compared to a recently proposed algorithm that adaptively tunes a RED parameter.     

Effect of swift heavy ion irradiation on structure, optical, and gas sensing properties of SnO2 thin films

Swift heavy ion irradiation has been successfully used to modify the structural, optical, and gas sensing properties of SnO₂ thin films. The SnO₂ thin films prepared by sol-gel process were irradiated with 75 MeV Ni⁺ beam at fluences ranging from 1 × 10¹¹ ion/cm² to 3 × 10¹³ ion/cm². Structural characterization with glancing angle X-ray diffraction shows an enhancement of crystallinity and systematic change of stress in the SnO₂ lattice up to a threshold value of 1 × 10¹³ ions/cm², but decrease in crystallinity at highest fluence of 3 × 10¹³ ions/cm². Microstructure investigation of the irradiated films by transmission electron microscopy supports the XRD observations. Optical properties studied by absorption and PL spectroscopies reveal a red shift of the band gap from 3.75 eV to 3.1 eV, and a broad yellow luminescence, respectively, with increase in ion fluence. Gas response of the irradiated SnO₂ films shows increase of resistance on exposure to ammonia (NH₃), indicating p-type conductivity resulting from ion irradiation.     

Mechanical properties of injection molded long fiber polypropylene composites,Part 1: Tensile and flexural properties

Innovative polymers and composites are broadening the range of applications and commercial production of thermoplastics. Long fiber‐reinforced thermoplastics have received much attention due to their processability by conventional technologies. This study describes the development of long fiber reinforced polypropylene (LFPP) composites and the effect of fiber length and compatibilizer content on their mechanical properties. LFPP pellets of different sizes were prepared by extrusion process using a specially designed radial impregnation die and these pellets were injection molded to develop LFPP composites. Maleic‐anhydride grafted polypropylene (MA‐g‐PP) was chosen as a compatibilizer and its content was optimized by determining the interfacial properties through fiber pullout test. Critical fiber length was calculated using interfacial shear strength. Fiber length distributions were analyzed using profile projector and image analyzer software system. Fiber aspect ratio of more than 100 was achieved after injection molding. The results of the tensile and flexural properties of injection molded long glass fiber reinforced polypropylene with a glass fiber volume fraction of 0.18 are presented. It was found that the differences in pellet sizes improve the mechanical properties by 3–8%. Efforts are made to theoretically predict the tensile strength and modulus using the Kelly‐Tyson and Halpin‐Tsai model, respectively. POLYM. COMPOS., 28:259–266, 2007. © 2007 Society of Plastic Engineers     

Automation of human behaviors and its prediction using machine learning

Microsystem Technologies - Prediction is a method of detecting a person's behavior toward online buying by evaluating publically available evaluations on the web. Understanding expressive human...     

Knowledge-driven description synthesis for floor plan interpretation

International Journal on Document Analysis and Recognition (IJDAR) - Image captioning is a widely known problem in the area of AI. Caption generation from floor plan images has applications in...     

Effect of graphene templated fluorides of Ce and La on the de/rehydrogenation behavior of MgH2

The present investigation describes the hydrogen storage properties of MgH₂ ball milled with different additives i.e. graphene templated rare earth metal (La and Ce) fluorides, CeF₄ and LaF₃. MgH₂ ball milled with graphene templated CeF₄ (MgH₂:CeF₄@Gr) has onset desorption temperature of 245 °C, which is 50 °C, 52 °C and 75 °C lower than MgH₂ ball milled with LaF₃ templated graphene, CeF₄ and LaF₃ respectively. CeF₄@Gr also shows the superior effect amongst all additives during rehydrogenation where MgH₂:CeF₄@Gr absorbs 5.50 wt% within 2.50 min at 300 °C under 15 atm H₂ pressure. Dual tuning effect, i.e. lowering of thermodynamic (62.77 kJ/mol H₂: lower from 74 kJ/mol for pristine MgH₂) and kinetics barrier (93.01 kJ/mol) has been observed for MgH₂:CeF₄@Gr. Additionally, MgH₂ ball milled with CeF₄@Gr shows good reversibility up to 24 cycles of de/rehydrogenation. The feasible working mechanism of CeF₄@Gr as additive for MgH₂ has been studied in detail with the help of Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction characterizations (XRD).