Magnetization studies of near-room-temperature flux-trapping phenomenon in CuO-based materials

DC magnetization studies on a variety of ceramic and crystalline YBaCuO samples indicate a superconducting-like flux-trappinig behavior occurring at similar temperatures as zero-resistance transition temperatures observed near room temperature. The flux-trapping behavior is exemplified by diamagnetic-like deviations from a positive magnetic background in the zero-field-cooled magnetization, by a divergence between the zero-field-cooled and field-cooled magnetization data, or by a positive Meissner effect in the field-cooled magnetization. These behaviors are consistent with a high-T _c (>250 K) superconducting phase in an inhomogeneous superconductor where the superconducting regions exist as defect structures or surface coatings and whose volume fraction is less than a few percent.     

Enhanced Hydrogen Generation from Empty Fruit Bunches by Charcoal Addition into a Downdraft Gasifier

Hydrogen production by co-gasification of empty fruit bunches of palm oil could be enhanced by adding charcoal. Physiochemical characterization of raw feedstocks was performed to determine their exergy potentiality. The raw feedstocks, gasified charcoal, and the end product of produced gas were analyzed by different techniques. Gasification experiments were performed using a pilot-scale downdraft gasifier. The heating value, composition of product gas, yield of hydrogen, and exergy efficiency were used to verify the improvement of hydrogen production during the co-gasification process. Charcoal with empty fruit bunches of palm oil leads to a much higher yield of hydrogen than lower charcoal ratios or solely empty fruit bunches. This enhanced hydrogen fuel can contribute to future energy demand.     

Improving performance through deep value profiling and specialization with code transformation

Specialization of code is used to improve the performance of the applications. However, specialization based on ineffective profiles deteriorates the performance. Existing value profiling algorithms are not yet able to address the issue of code size explosion incurred due to specialization of code. This problem can be mitigated by capturing data through profiling that would be useful for specialization of code with minimum code size.In this article, we present an approach to optimize code through value profiling and specialization with code transformation. The values of the parameters selected through an analysis of code are captured in the intervals which are automatically adapted to dynamic behavior of the application. The code is then specialized based on value profiles. The specialized code contains optimizations and may be converted back to the generalized code through a transformation. This approach facilitates the code to obtain optimizations through specialization with minimum size, and no runtime overhead.Using this approach, the experiments performed on Itanium-II (IA-64) architecture with icc compiler v 9.0 show a significant improvement in the performance of the SPEC 2000 benchmarks.     

Task scheduling for heterogeneous systems using an incremental approach

Effective scheduling of the tasks of a distributed application is one of the key factors in achieving improved performance. It results in an adequate utilization of the underlying resources and also reduces the total execution time of the application. Generating an optimal schedule for a distributed application is not a trivial task as it exists in the class of NP-complete problems. In this paper, a novel strategy called incremental subgraph earliest finish time (INCSEFT) is proposed. It is aimed at scheduling tasks on heterogeneous systems. It incorporates the use of a subgraph that grows incrementally by adding critical paths. At each step, the scheduling strategy attempts to minimize the schedule length. Considering a large set of nodes at an instance makes this approach perform better than other scheduling strategies used for heterogeneous systems. The experiments performed with several graphs show that the INCSEFT strategy produces significant improvement over the well-known HEFT, LOOKAHEAD and CEFT strategies used for scheduling heterogeneous systems.     

A cost-effective power-aware approach for scheduling cloudlets in cloud computing environments

On a cloud platform, the user requests are managed through workload units called cloudlets which are assigned to virtual machines through cloudlet scheduling mechanism that mainly aims at minimizing the request processing time by producing effective small length schedules. The efficient request processing, however, requires excessive utilization of high-performance resources which incurs large overhead in terms of monetary cost and energy consumed by physical machines, thereby rendering cloud platforms inadequate for cost-effective green computing environments. This paper proposes a power-aware cloudlet scheduling (PACS) algorithm for mapping cloudlets to virtual machines. The algorithm aims at reducing the request processing time through small length schedules while minimizing energy consumption and the cost incurred. For allocation of virtual machines to cloudlets, the algorithm iteratively arranges virtual machines (VMs) in groups using weights computed through optimization and rescaling of parameters including VM resources, cost of utilization of resources, and power consumption. The experiments performed with a diverse set of configurations of cloudlets and virtual machines show that the PACS algorithm achieves a significant overall performance improvement factor ranging from 3.80 to 23.82 over other well-known cloudlet scheduling algorithms..

     

Learning to dislike safe water products: results from a randomized controlled trial of the effects of direct and peer experience on willingness to pay

Low-cost point-of-use (POU) safe water products have the potential to reduce waterborne illness, but adoption by the global poor remains low. We performed an eight-month randomized trial of four low-cost household water treatment products in Dhaka, Bangladesh. Intervention households (n = 600) received repeated educational messages about the importance of drinking safe water along with consecutive two-month free trials with each of four POU products in random order. Households randomly assigned to the control group (n = 200) did not receive free products or repeated educational messages. Households' willingness to pay for these products was quite low on average (as measured by bids in an incentive-compatible real-money auction), although a modest share was willing to pay the actual or expected retail price for low-cost chlorine-based products. Furthermore, contrary to our hypotheses that both one's own personal experience and the influence of one's peers would increase consumers' willingness to pay, direct experience significantly decreased mean bids by 18-55% for three of the four products and had no discernible effect on the fourth. Neighbor experience also did not increase bids. Widespread dissemination of safe water products is unlikely until we better understand the preferences and aspirations of these at-risk populations.     

Tuning Specific Biomolecular Interactions Using Electro‐Switchable Oligopeptide Surfaces

The ability to regulate biomolecular interactions on surfaces driven by an external stimuli is of great theoretical interest and practical impact in the biomedical and biotechnology fields. Herein, a new class of responsive surfaces that rely on electro‐switchable peptides to control biomolecular interactions on gold surfaces is presented. This system is based upon the conformational switching of positively charged oligolysine peptides that are tethered to a gold surface, such that bioactive molecular moieties (biotin) incorporated on the oligolysines can be reversibly exposed (bio‐active state) or concealed (bio‐inactive state) on demand, as a function of surface potential. The dynamics of switching the biological properties is studied by observing the binding events between biotin and fluorescently labeled NeutrAvidin. Fluorescence microscope images and surface plasmon resonance spectral data clearly reveal opposite binding behaviors when +0.3 V or ?0.4 V vs. SCE are applied to the surface. High fluorescence intensities are observed for an applied positive potential, while minimal fluorescence is detected for an applied negative potential. Surface plasmon resonance spectroscopy (SPR) results provided further evidence that NeutrAvidin binding to the surface is controlled by the applied potential. A large SPR response is observed when a positive potential is applied on the surface, while a negative applied potential induces over 90% reduction in NeutrAvidin binding.     

Modulation of Biointeractions by Electrically Switchable Oligopeptide Surfaces: Structural Requirements and Mechanism

Understanding the dynamic behavior of switchable surfaces is of paramount importance for the development of controllable and tailor‐made surface materials. Herein, electrically switchable mixed self‐assembled monolayers based on oligopeptides have been investigated in order to elucidate their conformational mechanism and structural requirements for the regulation of biomolecular interactions between proteins and ligands appended to the end of surface tethered oligopeptides. The interaction of the neutravidin protein to a surface appended biotin ligand was chosen as a model system. All the considerable experimental data, taken together with detailed computational work, support a switching mechanism in which biomolecular interactions are controlled by conformational changes between fully extended (“ON” state) and collapsed (“OFF” state) oligopeptide conformer structures. In the fully extended conformation, the biotin appended to the oligopeptide is largely free from steric factors allowing it to efficiently bind to the neutravidin from solution. While under a collapsed conformation, the ligand presented at the surface is partially embedded in the second component of the mixed SAM, and thus sterically shielded and inaccessible for neutravidin binding. Steric hindrances aroused from the neighboring surface‐confined oligopeptide chains exert a great influence over the conformational behaviour of the oligopeptides, and as a consequence, over the switching efficiency. Our results also highlight the role of oligopeptide length in controlling binding switching efficiency. This study lays the foundation for designing and constructing dynamic surface materials with novel biological functions and capabilities, enabling their utilization in a wide variety of biological and medical applications.     

Current conveyor-based voltage-mode two-phase and four-phase quadrature oscillators

A voltage mode two-phase quadrature oscillator using plus-type second generation current conveyors [CCIIs(+)] is realized by using a simple technique. The basic building block for this technique is a voltage mode non-inverting band-pass filter. The two-phase quadrature oscillator is then transformed into a four-phase quadrature oscillator by replacing the two CCIIs(+) by two dual output, current conveyors [DO-CCIIs]. The proposed circuits enjoy attractive features such as use of grounded passive components, independent frequency control, outputs of almost equal magnitude and low sensitivity figures. Both the oscillator circuits are designed and verified using PSPICE simulation.     

Towards efficient XML parsing through minimization of JVM parameter space

The Journal of Supercomputing - A significant increase in the usage of Extensible Markup Language (XML) data for various protocols and standards emphasizes the development of efficient XML parsers....