Antioxidant activity of lettuce tree (Pisonia morindifolia R.Br.) and tamarind tree (Tamarindus indica L.) and their efficacy in peanut oil stability

Different solvent extracts of lettuce tree (Pisonia morindifolia R. Br.) and tamarind tree (Tamarindus indica L.) were tested for antioxidant activities. The extracts exhibited effective reducing power and higher radical scavenging efficacy against DPPH and hydroxyl radicals. They also showed metal chelating ability and inhibited peroxidation in the β-carotene/linoleic acid emulsion system. The extracts contained considerable levels of vitamin C, vitamin E, total phenolics, tannins, and total flavonoids estimated through standard spectrophotometric methods. As the acetone and methanol extracts of lettuce and tamarind tree recorded pronounced activities, their protective effects in stabilizing peanut oil were tested in terms of their peroxide value, free fatty acid contents, and p-anisidine values in comparison with the synthetic antioxidants butylated hydroxyanisole and butylated hydroxytoluene. Additionally, the antioxidant activity of the extract-treated oil samples and their phenolic contents were monitored to obtain a complete perspective of the influence of the phenolic compounds in oil stability. Results indicated that the selected leafy vegetables, besides acting as good sources of antioxidants, may serve as substitute for synthetic antioxidants in the stabilization of peanut oil.     

Time tick based method for measuring static errors of ADC

This paper presents a novel Time Tick based Built In Self Test (TT BIST) for measuring the static errors of an Analog to Digital Converter (ADC). The proposed method determines the period elapsed during transition between two consecutive digital levels and compares it with the ideal period of transition. A counter that works, at higher speed relative to the sampling rate of the ADC under test, is used. It counts the number of time ticks occurred during every transition. The required ramp signal is generated dynamically, using current source with digital switch for selecting the equivalent test signal. Further to support testing of errors in ratiometric ADC, a slope conditioning module is also implemented. The entire computation cycle is done in a single ramp cycle whereas in conventional histogram method multiple waveforms are required. Thus, the proposed TT method requires less time to achieve desired accuracy levels by choosing the appropriate slope of the ramp signal.     

Efficiency of a dye-sensitized photoelectrochemical device using thionine and triturated zinc oxide at different potency

A new and novel material, triturated zinc oxide nanoparticles, which is eco-friendly, easily available, low in cost, has been used here for the first time for enhancement of photovoltage generation and efficiency of a dye-sensitized photoelectrochemical device. This material when diluted and strongly agitated, together termed as potentized, is used as nanomedicine for centuries. This study using this material at two different potencies (6C and 30C) shows that addition of this material to thionine dye of concentration 0.85 μM enhances photovoltage generation significantly. The efficiency obtained with the latter is ~0.41%, whereas it is ~0.003% with dye only.     

Resource provisioning based on preempting virtual machines in distributed systems

Resource provisioning is one of the main challenges in large‐scale distributed systems such as federated Grids. Recently, many resource management systems in these environments have started to use the lease abstraction and virtual machines (VMs) for resource provisioning. In the large‐scale distributed systems, resource providers serve requests from external users along with their own local users. The problem arises when there is not sufficient resources for local users, who have higher priority than external ones, and need resources urgently. This problem could be solved by preempting VM‐based leases from external users and allocating them to the local ones. However, preempting VM‐based leases entails side effects in terms of overhead time as well as increasing makespan of external requests. In this paper, we model the overhead of preempting VMs. Then, to reduce the impact of these side effects, we propose and compare several policies that determine the proper set of lease(s) for preemption. We evaluate the proposed policies through simulation as well as real experimentation in the context of InterGrid under different working conditions. Evaluation results demonstrate that the proposed preemption policies serve up to 72% more local requests without increasing the rejection ratio of external requests. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and characterisation of nanobioactive glass for biomedical applications

In recent years, bioactive materials have become important in applications such as implantation, bone regeneration, scaffold, oral implantation and antioxidant materials because of their excellent bioactivity, biocompatibility, osteoconductivity and osteoinductive properties. When exposed to simulated body fluid, bioactive glasses have the ability to bond with both hard and soft tissues through the formation of a hydroxyapatite layer. Nowadays, nanotechnology is emerging as a nascent technology in all disciplines because of its high surface-to-volume ratio and unique properties at nanoscale length. The impact of nanotechnology in biomaterials is of interest because of the enhancement in their biocompatibility and bioactivity. In this investigation, the preparation of nanobioactive glasses by using different methods (such as sol-gel, hydrothermal and sonochemical) is discussed in detail. The structural and morphological characterisation of the prepared samples was made.     

OpenStack Neat: a framework for dynamic and energy‐efficient consolidation of virtual machines in OpenStack clouds

Dynamic consolidation of virtual machines (VMs) is an efficient approach for improving the utilization of physical resources and reducing energy consumption in cloud data centers. Despite the large volume of research published on this topic, there are very few open‐source software systems implementing dynamic VM consolidation. In this paper, we propose an architecture and open‐source implementation of OpenStack Neat, a framework for dynamic VM consolidation in OpenStack clouds. OpenStack Neat can be configured to use custom VM consolidation algorithms and transparently integrates with existing OpenStack deployments without the necessity of modifying their configuration. In addition, to foster and encourage further research efforts in the area of dynamic VM consolidation, we propose a benchmark suite for evaluating and comparing dynamic VM consolidation algorithms. The proposed benchmark suite comprises OpenStack Neat as the base software framework, a set of real‐world workload traces, performance metrics and evaluation methodology. As an application of the proposed benchmark suite, we conduct an experimental evaluation of OpenStack Neat and several dynamic VM consolidation algorithms on a five‐node testbed, which shows significant benefits of dynamic VM consolidation resulting in up to 33% energy savings. Copyright © 2014 John Wiley & Sons, Ltd.