Thermodynamic Properties of YbRhO<Subscript>3</Subscript> and Phase Relations in the System Yb-Rh-O

Thermodynamic properties of the ternary oxide YbRhO₃ were determined by using a solid-state electrochemical cell incorporating calcia-stabilized zirconia as the solid electrolyte in the temperature range from 900 to 1300 K. The standard Gibbs energy of formation of YbRhO₃ from component binary oxides Yb₂O₃ with C-rare earth type structure and Rh₂O₃ with orthorhombic structure can be represented by the equation,

$$\Delta_{\text{f(ox)}} G^{\text{o}} ( \pm 130)/{\text{J/mol}} = - 43164 + 3.436\,({\text{T/K}}).$$

Standard enthalpy of formation of YbRhO₃ from elements in their normal standard states is ?1153.18(±3) kJ/mol and its standard entropy is 100.93(±0.6) J/K/mol at 298.15 K. The decomposition temperature of YbRhO₃ is 1671(±3) K in pure oxygen, 1566(±3) K in air and 1047(±3) K at an oxygen partial pressure of \(\left( {P_{{{\text{O}}_{2} }} /{\text{P}}^{\text{o}} } \right) = 10^{ - 6}\), where P^o = 0.1 MPa is the standard pressure. Decomposition temperature was confirmed by DTA/TGA. Phase diagrams for the system Yb-Rh-O are computed using the thermodynamic data.

     

Core/shell nanoassembly of amphiphilic naproxen‐polyethylene glycol: synthesis,characterisation and evaluation as drug delivery system

Small molecule‐based amphiphiles self‐assemble into nanostructures (micelles) in aqueous medium which are currently being explored as novel drug delivery systems. Here, naproxen‐polyethylene glycol (N‐PEG), a small molecule‐derived amphiphile, has been synthesised, characterised and evaluated as hydrophobic drug carrier. ¹ H, ¹³ C Nuclear magnetic resonance (NMR), mass spectrometry (MS) and Fourier‐transform infrared spectroscopy (FTIR) confirmed the formation of N‐PEG and dynamic light scattering (DLS) revealed the formation of nano‐sized structures of ∼228 nm. Transmission electron microscope (TEM) analysis showed aggregation behaviour of the structures with average size of ∼230 nm. Biodegradability aspect of the micellar‐structured N‐PEG was demonstrated by lipase‐mediated degradation studies using DLS and TEM. High encapsulation efficiency followed by release in a sustained manner of a well‐known anticancer drug, doxorubicin, demonstrated the feasibility of the new drug delivery system. These results advocate the promising potential of N‐PEG micelles as efficient drug delivery system for specific delivery to cancerous cells in vitro and in vivo.Inspec keywords: cancer, biodegradable materials, cellular biophysics, encapsulation, biomedical materials, drugs, nanofabrication, drug delivery systems, nanomedicine, self‐assembly, nanoparticles, transmission electron microscopy, colloids, molecular biophysics, light scattering, hydrophobicity, biochemistry, enzymes, core‐shell nanostructures, nanocomposites, proton magnetic resonance, Fourier transform infrared spectra, mass spectroscopic chemical analysisOther keywords: hydrophobic drug carrier, nanosized structures, transmission electron microscope analysis, doxorubicin, N‐PEG micelles, core/shell nanoassembly, amphiphilic naproxen‐polyethylene glycol, drug delivery system, small molecule‐based amphiphiles self‐assemble, small molecule‐derived amphiphile, ¹ H NMR, ¹³ C NMR, MS, FTIR, dynamic light scattering, aggregation behaviour, biodegradability aspect, lipase‐mediated degradation studies, encapsulation efficiency, cancerous cells     

Timing Traceability and the Link Between ISRO-NPLI

We present an algorithm for timescale prediction of IRNSS Network Time (IRNWT) using a GNSS link for daily exchange of data between Indian Space Research Organization and CSIR-NPL. A link between CSIR-NPL and IRNWT through Two Way Satellite Time and Frequency Transfer is also being established.     

Enhanced field emission and improved supercapacitor obtained from plasma-modified bucky paper

The surface morphology of bucky papers (BPs) made from single-walled carbon nanotubes (CNTs) is modified by plasma treatment resulting in the formation of vertical microstructures on the surface. The shapes of these structures are either pillarlike or conelike depending on whether the gas used during plasma treatment is Ar or CH(4) . A complex interplay between different factors, such as the electric field within the plasma sheath, polarization of the CNT, intertubular cohesive forces, and ion bombardment, result in the formation of these structures. The roles played by these factors are quantitatively and qualitatively analyzed. The final material is flexible, substrate-free, composite-free, made only of CNTs, and has discrete vertically aligned structures on its surface. It shows enhanced field emission and electrochemical charge-storage capabilities. The field enhancement factor is increased by 6.8 times, and the turn-on field drops by 3.5 times from an initial value of 0.35 to 0.1 V μm(-1) as a result of the treatment. The increase in Brunauer-Emmett-Teller surface area results in about a fourfold improvement in the specific capacitance of the BP electrodes. Capacitance values before and after the treatments are 75 and 290 F g(-1) , respectively. It is predicted that this controlled surface modification technique could be put to good use in several applications based on macroscopic CNT films.     

Synthesis of cube-shaped gold nanostructures by electron irradiation

The needle-like gold nanostructures were synthesized by using chloroauric acid (HAuCl₄) as a metal precursor and sodium borohydride (NaBH₄) as the reducing agent. These needle-like nanostructures of gold were irradiated with high energy electrons (E ~ 6 MeV, ? ~ 10¹² e cm⁻² s⁻¹). The pre- and post-irradiated gold nanostructures were characterized by Scanning Electron Microscopy (SEM), UV-vis spectroscopy, X-ray Diffraction (XRD) and contact angle measurement (GBX-Model Digidrop) techniques. The results of the SEM revealed that after electron irradiation, the needle-like gold structures got fragmented into identical cube-shaped gold nanostructures, though of different sizes. The XRD analysis indicated that the average crystallite size of the gold nanostructures remained unchanged even after irradiation with high energy electrons. A glass surface showed hydrophilic behavior when coated with needle-like nanostructures and became ultra hydrophilic when coated with cube-shaped gold nanostructures.     

Quality of chilled ready-to-bake pizza stored in air and under modified atmospheres: Microbiological and sensory attributes

Modified atmosphere packaging (MAP) studies on microbiological and sensory analysis were conducted to extend the shelf life of ready-to-bake pizza stored at 7±1°C. The gas combinations used were: atm1: air (control), atm2: CO₂ (100%), atm3: N₂ (100%), atm4: 50% CO₂/50% N₂. Total plate count (TPC), yeasts/molds (Y/M), coliforms, lactic acid bacteria (LAB), psychrotrophs, and anaerobic spore formers were estimated at time intervals of 0, 5, 10, 15, and 20 days. TPC and LAB of pizza samples (atm1) reached 7.10 and 8.14 log CFU/g after 10 days of storage, respectively. Coliforms, psychrotrophs, and Y/M were significantly higher (p<0.05) for pizza samples stored in atm1 than other storage conditions of MAP. Finally, counts of anaerobic spore formers were low (<3 log CFU/g) irrespective of the packaging conditions throughout the entire storage period. It was concluded that among the 4 atmospheres examined, atm2 (100% CO₂) was the best, followed by atm4>atm3>atm1 respectively, in descending order. MAP conditions under this study may extend shelf life of pizza to considerable amount of time.     

Thirty years of a ban on the sale of noniodized salt: impact on iodine nutrition in children in Himachal Pradesh, India

BACKGROUND: A survey conducted by the central iodine-deficiency disorders team in Himachal Pradesh, a state in the goiter-endemic belt of India, revealed that 10 of its 12 districts have an endemic prevalence of goiter. The survey was conducted to provide health program managers data to determine whether it would be necessary to initiate intervention measures. OBJECTIVE: To assess the status of urinary iodine excretion and household salt iodization levels after three decades of a complete ban on the sale of noniodized salt in this goiter-endemic state in India as measured by assessment of urinary iodine excretion levels and iodine content of salt at the household level. METHODS: The guidelines recommended by WHO/ UNICEF/ICCIDD for a rapid assessment of salt iodization were adopted. In each of the 12 studied districts, all senior secondary schools were enlisted and one school was selected by using a random sampling procedure. Two hundred fifty children 11 to 18 years of age were included in the study. Urine samples were collected from a minimum of 170 children and analyzed using the wet digestion method. Salt samples were also collected from a minimum of 170 children and analyzed using the spot testing kit. RESULTS: All districts had a median urinary iodine excretion level > 200 microg/L and 82% of the families were consuming salt with an iodine content of 15 ppm or higher. CONCLUSIONS: The results of the present study high-light the successful implementation of the salt iodization program in the state of Himachal Pradesh. This positive impact may be due to the comprehensive strategy adopted by the state government to improve the quality of salt, development of an effective monitoring information system and effective information, education, and communication activities.     

Understanding critical factors for the quality and shelf-life of MAP fresh meat: a review

Due to increased demands for greater stringency in relation to hygiene and safety issues associated with fresh food products, coupled with ever-increasing demands by retailers for cost-effective extensions to product shelf-lives and the requirement to meet consumer expectations in relation to convenience and quality, the food packaging industry has rapidly developed to meet and satisfy expectations. One of the areas of research that has shown promise, and had success, is modified atmosphere packaging (MAP). The success of MAP-fresh meat depends on many factors including good initial product quality, good hygiene from the source plants, correct packaging material selection, the appropriate gas mix for the product, reliable packaging equipment, and maintenance of controlled temperatures and humidity levels. Advances in plastic materials and equipment have propelled advances in MAP, but other technological and logistical considerations are needed for successful MAP systems for raw chilled meat. Although several parameters critical for the quality of MA packed meat have been studied and each found to be crucial, understanding of the interactions between the parameters is needed. This review was undertaken to present the most comprehensive and current overview of the widely available, scattered information about the various integrated critical factors responsible for the quality and shelf life of MA packed meat with an interest to stimulate further research to optimize different quality parameters.     

Laboratory studies on combustion cavity growth in lignite coal blocks in the context of underground coal gasification

Cavity formation is an important phenomenon in the underground coal gasification (UCG) process. In the early stages of cavity formation, only the combustion reaction is performed in order to stabilize the temperature field. In the present work, we study the formation of the combustion cavity and the effect of various design and operating parameters such as the distance between the wells, feed flow rate and operation time, on its evolution. This paper presents details of laboratory-scale experiments that demonstrate the shape and size of the combustion cavity, and their dependence on various parameters. Empirical correlations for the cavity volume and dimensions in various directions are developed, which indicate the strong effects of mass transport. Results from computational fluid dynamics (CFD), which map the velocity profiles in the cavity, support the experimental observations.