Mobile computing raises many new issues, such as lack of stable storage, low bandwidth of wireless channels, high mobility and limited battery life. These. issues make traditional checkpointing algorithms unsuitable for checkpointing mobile distributed systems. Minimum process Coordinated checkpointing is good approach to introduce fault tolerance in a distributed system transparently. This approach is domino-free and requires at most two checkpoints of each process on stable storage, and forces only interacting processes to checkpoint. Sometimes, it also requires piggybacking of information onto normal messages, blocking of the underlying computation or taking some useless checkpoints. In this paper, we propose a non-intrusive minimum process synchronous checkpointing protocol for mobile distributed systems, where only the minimum number of tentative checkpoints is taken. We also optimize and the number of useless forced (mutable) checkpoints and message overheads as compared to [4],

Chitosan coated FeO NPs are effective antimicrobial agents and so may be developed as a microbial resistant coating for biomedical devices.

Graphene quantum dots (GQDs) are one of the most promising luminescent carbon derived nanomaterials decorated with multiple useful functional groups and remarkable optoelectronic properties. Heteroatom doping of hexagonal carbon sheet of GQDs is an effective strategy to tailor their properties to meet desired application. In this work, sulfur doped GQDs (S-GQDs) were synthesized by simply pyrolyzing citric acid (CA) as a source of carbon and 3-Mercaptopropionic acid as a source of sulfur dopant. The optimal reaction conditions (ratio of the carbon to dopant source, temperature and time of reaction) were obtained while investigating their effect on the quantum yield and fluorescence properties of GQDs and, are hereby, reported for the first time. The as-synthesized S-GQDs were extensively characterized by different analytical techniques such as transmission electron microscopy (TEM), UV-vis Spectroscopy (UV), Fourier transform infrared spectroscopy, photoluminescence (PL) and x-ray Photoelectron Spectroscopy. S-GQDs were found uniform in size (∼4 nm) and spherical in shape with strong blue fluorescence. Further, for in-depth analysis of experimental results and underlying phenomena, theoretical studies based on density functional theory were performed for chemical structure optimization, possible sites of doping and density of states calculation. The synthesized S-GQDs exhibited excellent solubility in water, a stronger fluorescence and desirably higher quantum yield (57.44%) as compared to that of previously reported undoped GQDs. These successfully demonstrated unique and improved properties of S-GQDs present them as a potential candidate for biomedical, optical, electrical and chemical applications.

In this work, a new nanocomposite (Ag@S-GQDs) have been synthesized using one-step facile synthesis process and their antibacterial as well as cytotoxicity properties were investigated systematically.

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The study of the radiation hazards from building materials is of interest in many countries. So, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The present study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 226Ra, 232Th and 40K in building materials collected from the Northeastern part of Haryana state of India using gamma ray spectrometry. Places are in the vicinity of Shivalik range of Himalayas. The activity of radium, thorium and potassium in various soil samples varied from 27 ± 1.2 to 51 ± 1.5 Bq/kg, 42 ± 1.5 to77 ± 2.3 Bq/kg and 277 ± 3.2 to 584 ± 6.1 Bq/kg and in various building materials varied from 14 ± 0.4 to 87 ± 7.7 Bq/kg, 6 ± 0.3 to 24 ± 1.1 Bq/kg and 26 ± 0.4 to 245 ± 3.7 Bq/kg, respectively. The values of absorbed annual effective doses (indoors and outdoors) were found to vary in various soil samples from 50 to 95 nGyh−1, 0.24 to 0.46 mSv and 0.06 to 0.12 mSv and in various building materials found to vary from 11 to 57 nGyh−1, 0.05 to 0.28 mSv and 0.01 to 0.07 mSv, respectively.

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