Superfluidity of Dense 4^4He in Vycor

We calculate properties of a model of $^4$He in Vycor using the Path Integral Monte Carlo method. We find that $^4$He forms a distinct layered structure with a highly localized first layer, a disordered second layer with some atoms delocalized and able to give rise to the observed superfluid response, and higher layers nearly perfect crystals. The addition of a single $^3$He atom was enough to bring down the total superfluidity by blocking the exchange in the second layer. Our results are consistent with the persistent liquid layer model to explain the observations. Such a model may be relevant to the experiments on bulk solid $^4$He, if there is a fine network of grain boundaries in those systems.Comment: 4 pages, 4 figure

Baghdad Subgrade Resilient Modulus and liquefaction Evaluation for Pavement Design using Load Cyclic Triaxial Strength

Pavements fail for different reasons; poor design, poor materials and poor construction methods are the most common. The pavement foundation (subgrade) represents one of the key elements in the pavement design. The American Association of State Highway and Transportation officials (AASHTO) published the AASHTO Guide for Design of Pavement Structures (AASHTO, 1986) in which the use of Resilient Modulus (Mr) was adopted as the principal soil property contributing to the design of flexible pavements. It can consider that resilient modulus (Mr) is a key value in pavement design. The present study uses the standard laboratory test for load cyclic Triaxial strength to evaluate the resilient modulus and liquefaction condition of some Baghdad soils ,as well as using the neural network approach to develop a model that can be used to predict resilient modulus values for Baghdad soils . The model uses the results of routine laboratory tests like specific gravity, water content, Atterberg limits, soil classification and unconfined compressive strength to predict Mr. It is well-known that the Performance of resilient modulus tests are difficult, expensive and time consuming and hence there has been an interest in adopting the Ohio State University  mathematical model (OSU Model) introduced by Kim 2004 and confirmed by Rodgers 2006 that satisfactorily predicts resilient modulus values without the necessity of a laboratory test. It is very important for a mathematical model to accommodate new data as it becomes available. It is concluded that soil brought from Baghdad City exhibited the resilient modulus (Mr) of pavement subgrade soils which has been adopted by the American Association of State Highway and Transportation Officials (AASHTO) for the purpose of designing flexible roadway pavement systems, values ranging from 40 MPa to about 100MPa. Based on ASTM subgrade resilient modulus criterion, the A-7-5 and A-6 untreated subgrade soil would be classified as fair to poor (unacceptable as a competent subgrade). To prove the capability of the network, Mr predicted values for Baghdad soil were compared with its corresponding Mr measured. It is concluded that Baghdad soils need to be provided with new network and model with some modification needed to be done on the OSU models to provide a good estimation of Mr for the Baghdad soils. The results of cyclic load test carried out in laboratory to conduct Liquefaction indicate that for a given initial water content and specific dry density with initial effective stress, it is concluded that generally all samples didn’t exhibit significant gain in liquefaction condition and didn’t show conflict values due to the reduction in the rate of pore water pressure generation and shear strain of all samples subjected to cyclic loading. they shows withstanding against liquefaction by reaching high value of Normalized principal Stress when reaching to critical built up of Pore water pressure which lead to the fact that a liquefied condition could not possibly develop in those soils. Keywords: Resilient Modulus, C.B.R, Subgrade Compaction, Pavement Desig

A critically systemic approach for understanding information systems failure in the UK public sector

In the United Kingdom, the implementation of large-scale Information System (IS) projects has led to multifarious problems over the last few decades, and this seems to be an ongoing situation. As a result, within the public sector organisations, a number of information systems have failed to meet their pre-specified goals in spite of the large amount money and effort spent on IS projects. Information system projects are highly complex and the complexity is varied based on the different aspects involved including technical, organisational, and social, while the traditional concepts have less of an effect when aiming to achieve considerable improvement to cope with the increasing complexity of the situation. This was apparent in the study of two examples of large-scale IS failures in the UK public sector, whereas the attention was on examining discrete elements without considering the potential relationships between the elements. The current study, therefore, proposes a system approach as an alternative to understanding the nature of large-scale IS failures in the UK public sector. The systems approach, as an advanced movement in management science, seeks to identify social context and organizational issues and to use a combination of methodologies, methods, tools, and techniques to help problem solvers better control problematic situations. Thus, the Systems Approach is privileged because it offers a holistic approach to look at the problematic situation rather than being focused solely on a particular aspect instead of the interconnected relationships among its parts. The alternative approach benefits from the new problem solving and practical intervention strategies toward a better understanding of the complexity, diversity, and change of the problematic situations, while providing a comprehensive insight into the real-world problem of IS failure. This extends to identifying the contradictory issues related to power, conflict, and culture affecting the situation. Within the Systems Approach the researcher employed critical pluralism to the current study, which is theoretically built upon a combination of methodologies and methods designed for a particular intervention.Some findings of the research disclose that large-scale IS failure in the UK public sector is treated inadequately, and solutions proposed to reduce the rate of failure ignore this complexity. The findings also reveal that there are four factors affecting large-scale IS failure in the UK public sector: political factors; organisational factors; technical factors; and human factors. The founding related to the methodology, the researcher found that critical pluralism appears able to capture a set of systemic processes: appreciation; analysis; assessment; and action. All these processes were conducted collectively and supported by a particular type of collected data activities in the way of identifying the natures of the IS system and its associated sub-systems. Finally, by conducting a particular Systems Approach technique to assess the IS failure problem in the UK public sector context, it cannot be claimed that the solution is applicable to other situations in another context because the approach itself views any problematic situation as unique and hard to be generalised. Nevertheless, the discovery of such solutions leads to the accumulation of knowledge that contributes to reductions in the rates of IS failure in general

Characterizing the Performance of a Ferrofluid-Based Electromagnetic Energy Harvester under Direct and Parametric Excitations

When a container carrying a magnetized ferrofluid is subjected to external mechanical stimuli, the sloshing motion of the magnetized ferrofluid generates a time-varying magnetic flux, which can be used to induce an electromotive force in a coil placed adjacent to the container. This process generates an electric current in the coil, and therewith, can be used to transduce external vibrations into electric energy providing a unique approach for vibration energy harvesting using liquid-state transduction materials. As compared to traditional vibratory energy harvesters that employ soli transduction elements, this approach offers several advantages including, but not limited to, conformability to different shapes and increased sensitivity to external excitations. In this dissertation, a bench-top experiment was first constructed to demonstrate the feasibility of the proposed concept for vibratory energy harvesting. A rectangular plastic container carrying ferrofluid was placed inside a pick-up coil which is wound around a ferrite core. The whole setup was mounted on an electrodynamic shaker table which provided a controlled acceleration at the containers base. The external magnetization is applied using permanent magnets with maximum magnetic field intensity of 92 mT. Series of experiments were carried out to determine the optimal configuration of coil windings with respect to the sloshing and magnetic field directions. It was found that the output power of the device increases an order of magnitude when the coil is wound perpendicular to the sloshing motion and magnetic field lines. For the optimal configuration determined experimentally, a nonlinear analytical model which governs the electro-magneto-hydrodynamics of the harvester was developed. An approximate analytical solution of the model was obtained using perturbation methods for two different types of excitation; namely for a case involving the primary resonance excitation of the first mode and a case involving the principle parametric resonance of the first two modes. For the case involving the primary resonance of the first mode, it was observed the approximate analytical solution fails to capture the qualitative behavior of the harvester’s response for some ferrofluid height to container width ratios. Upon further inspection, it was observed that for those critical height-to-width ratios, the sloshing conditions are such that a two-to-one internal resonance between the first two sloshing modes can be activated. To account for the internal resonance, a modified version of the perturbation solution was devised and used to obtain a solution of the governing equations capable of capturing the influence of the internal resonance on the dynamics. Overall, it was shown that the developed model is capable of capturing the qualitative behavior of the dynamics of the harvester for both cases of excitation and for various magnetic field distributions. It was observed that the orthogonality of the magnetic field distribution along the width the container to the shape of the mode being excited plays a critical role in determining the output power of the harvester. Specifically, regardless of the input excitation level and the size of the induced sloshing waves, very little energy can be harnessed from the environment when the magnetic field distribution is an even (odd) function of the containers width while the mode shape being excited is an odd (even) function of the width. It was shown that, unlike the primary resonance scenario, a threshold excitation level must be achieved in the principle parametric resonance case before the harvester can produce measurable voltage levels. This threshold increases with the strength of the applied magnetic field

The concept of unnatural roof garden to reduce energy consumption and electricity bills for houses in Bahrain

The green roof technology has become one of the most important techniques in present days to reduce energy consumption inside buildings especially in hot climates. Bahraini residential roofs are usually constructed with precast concrete, which, alongside with natural plant needs (soil and irrigation) makes the natural roof garden technique difficult to implement. This research will present a new option to reduce the energy consumption inside residential buildings in Bahrain. The new concept depends on using unnatural grass (turf) added on the concrete roofs for residential buildings in Bahrain. A simulation computer program "e-QUEST" will be used as simulation tool; to calculate the energy consumption and energy costs for each case study. The use of unnatural grass on the concrete roofs will reduce (150,321.6B.D = 414.88 Dollars) annually for the selected model and an annual energy consumption reduction of (68 kWh). The annual reduction in energy consumption for each square meter is (7.556 kWh). The maximum reduction for bills' energy consumption is verified in July, while the minimum reduction for bills' energy consumption is verified in January. Keywords: Reduce energy, Energy costs, Energy consumption, Unnatural roof garden, Bahraini houses

Hepatic glucokinase promoter polymorphism is associated with hepatic insulin resistance in Asian Indians.

BACKGROUND: The role of glucokinase (GCK) in the pathogenesis of maturity-onset diabetes of the young is well established. However, its role in the common form of type 2 diabetes is far from convincing. We investigated the role of the G-to-A polymorphism in the hepatic GCK promoter on insulin sensitivity and beta cell function in 63 normotensive Asian Indians with normal glucose tolerance. As proposed by Matsuda and DeFronzo, hepatic insulin sensitivity (ISI(H)) and total body insulin sensitivity (ISI(M)) were estimated from the oral glucose tolerance test. Beta cell function was estimated using %B from the Homeostasis Model Assessment and insulingenic index (dI/dG). RESULT: We identified 38 GG, 24 GA, and one AA subjects. The AA subject was pooled with the GA subjects during the analysis. No difference was noted in the demographic features between the two genotypic groups (GG vs. GA/AA). Compared to the GG group, the GA/AA group had a lower ISI(H) (p=0.002), a lower ISI(M) (p=0.009), a higher %B (p=0.014), and a higher dI/dG (p=0.030). Multivariate analysis revealed that this polymorphism is an independent determinant for ISI(H) (p=0.019) and along with age, waist-hip ratio, gender, and diastolic blood pressure accounted for 51.5% of the variation of ISI(H). However, this polymorphism was a weak, but independent determinant for ISI(M) (p=0.089) and %B (p=0.083). Furthermore, it had no independent effect on dI/dG (p=0.135). CONCLUSIONS: These data suggest that the G-to-A polymorphism in the hepatic GCK promoter is associated with hepatic insulin resistance in Asian Indians

Criterion for polynomial solutions to a class of linear differential equation of second order

We consider the differential equations y''=\lambda_0(x)y'+s_0(x)y, where \lambda_0(x), s_0(x) are C^{\infty}-functions. We prove (i) if the differential equation, has a polynomial solution of degree n >0, then \delta_n=\lambda_n s_{n-1}-\lambda_{n-1}s_n=0, where \lambda_{n}= \lambda_{n-1}^\prime+s_{n-1}+\lambda_0\lambda_{n-1}\hbox{and}\quad s_{n}=s_{n-1}^\prime+s_0\lambda_{k-1},\quad n=1,2,.... Conversely (ii) if \lambda_n\lambda_{n-1}\ne 0 and \delta_n=0, then the differential equation has a polynomial solution of degree at most n. We show that the classical differential equations of Laguerre, Hermite, Legendre, Jacobi, Chebyshev (first and second kind), Gegenbauer, and the Hypergeometric type, etc, obey this criterion. Further, we find the polynomial solutions for the generalized Hermite, Laguerre, Legendre and Chebyshev differential equations.Comment: 12 page

Effect of manganese doping on the size effect of lead zirconate titanate thin films and the extrinsic nature of dead layers

We have investigated the size effect in lead zirconate titanate (PZT) thin films with a range of manganese (Mn) doping concentrations. We found that the size effect in the conventional Pt/PZT/Pt thin-film capacitors could be systematically reduced and almost completely eliminated by increasing Mn doping concentration. The interfacial layer at the electrode-film interface appears to disappear almost entirely for the PZT films with 2% Mn doping levels, confirmed by the fits using the conventional in-series capacitor model. Our work indicates that the size effect in ferroelectrics is extrinsic in nature, supporting the work by Saad et al. Other implications of our results have also been discussed. By comparing a variety of experimental studies in the literature we propose a scenario that the dead layer between PZT (or barium strontium titanate, BST) and metal electrodes such as Pt and Au might have a defective pyrochlore/fluorite structure (possibly with a small portion of ferroelectric perovskite phase).Comment: 21 pages, 6 figure