Modeling and Simulation of Condensation on Plastic Condenser Cooling under Night Sky

The Kutch region of north-west India is hot and semiarid, chronically short of drinking water. Dew forms frequently in the areas near the coast, over a span of eight-month (October- May) coinciding with the entire dry part of the year. Dew water is potable and safe. Dew harvest systems - devices to condense and collect dew - have been developed which could be installed on building roofs (condenser-on-roof), open ground (condenser-on-ground) and on frames (condenser-on-frames). The key component is the condenser, made of thin plastic film insulated underneath, which cools at night by radiative exchange with cloud-free sky. Condensation occurs when the film cools to or below the dew point of the surrounding air and humidity level is high - upwards of 85%. Over the season of eight months, 15 – 20 mm of dew water can be harvested. In this region where rainfall is very erratic and in normal years only 300 mm, harvested dew water can be an appreciable supplement. It can also be a small but critical supply for plants in nurseries. Design principle of efficient dew condenser is discussed and dew water collection in some recently installed working systems reported.

Fourier Representation of Climatic Data of Kothara-Kutch

Fourier series representations of some climatic variables were developed using data from the site of an experimental greenhouse at Kothara (Kutch). Hourly data was averaged over a month to yield a profile of an average day of that month. That was put through harmonic analysis to determine Fourier coefficients . Analytical expressions would be useful to those working on modelling.

Evidence-Based Management in "Macro" Areas: The Case of Strategic Management

Despite its intuitive appeal, evidence-based management (EBMgt) faces unique challenges in "macro" areas such as Organization Theory and Strategy Management, which emphasize actions by organizations, and business and corporate leaders. The inherent focus on complex, multi-level and unique problems present serious challenges. EBMgt will nurture the establishment of a new model of research that is not only cumulative in its knowledge-building but also promotes engaged scholarship. Further, the uncertainty and conflict that characterize "macro" decision contexts heighten the need for EBMgt. We put forward four recommendations to advance EBMgt: (1) using more sophisticated meta-analyses; (2) providing syntheses that go beyond quantitative summaries; (3) engaging in a disciplined conversation about our implicit "levels of evidence" frameworks; and (4) developing decision supports.

Decision Support System for Design and Evaluation of Pipeline Projects

Petronet India Limited (PIL) was created to give impetus to investments in pipeline projects for transportation of petroleum products in the country. Since these projects have a long life and require large investments, correct assessment of location, capacity and financial viability are of critical importance. This paper is based on the study undertaken for PIL to evaluate a few of their pipeline projects. The study resulted in creation of a comprehensive software package that is capable of operational and financial evaluation of pipeline projects based on countrywide view on production and distribution of petroleum products. The core of the package is an LP based optimization model. The package is capable of performing sensitivity analysis to investigate the impact of uncertainty on the proposed project due to from changes in the values of key factors including distribution network and capacities, refining capacities and pattern of demand. •A model is developed for identification of viable pipeline projects, taking into account the demand and capacity additions to production and distribution network for petroleum products in the future. •The model can be used for financial evaluation of such projects based on appropriate assumptions to forecast the investments required as well as the net cash flows from the project. •The solution procedure is implemented for the models developed in the form of a software package that would allow the decision maker to experiment with assumption and generate solutions with ease and with little manual intervention. •The software package developed above is further embellished so that it also provides additional information to the decision maker in the form of reports that contain details of movement of products and the mode combinations used for the movements.

Indian Convertible Bonds with Unspecified Terms: An Empirical Study

Indian convertible bonds have two peculiar features that make them possibly unique in the world: a) the bonds are compulsorily converted into equity without any option, and b) the conversion terms are not specified at the time of issue but are left to be determined subsequently by the Controller of Capital Issues (CCI) who is the government functionary regulating capital issues in India. A naive model would say that the market simply forms an estimate of the likely conversion terms and then values the bond as if these terms were prespecified. This paper examines the market prices of one of the largest issues of Indian convertible bonds with unspecified terms. The empirical investigation convincingly rejects the naive model and demonstrates that changes in the markets expectation of the conversion terms are a significant factor affecting the pricing relationship. These changes are significantly correlated with the stock price itself. We do not, however, find any evidence that the market expects the CCI to adjust the conversion terms on the basis of the actual market price to protect the bondholder. But, there is strong evidence that changes in expected conversion terms affect the share price through the dilution effect. Since the unspecified terms have only added to the uncertainty of the bondholders without giving them any perceived benefits we recommend that this system should be abolished. In a companion paper, Barua and Varma (1991) present a theoretical valuation model for the Indian convertible bonds with unspecified terms. The empirical results in this paper confirm the predictions of that model.

Kruskal coordinates as canonical variables for Schwarzschild black holes

We derive a transformation from the usual ADM metric-extrinsic curvature variables on the phase space of Schwarzschild black holes, to new canonical variables which have the interpretation of Kruskal coordinates. We explicitly show that this transformation is non-singular, even at the horizon. The constraints of the theory simplify in terms of the new canonical variables and are equivalent to the vanishing of the canonical momenta. Our work is based on earlier seminal work by Kuchar in which he reconstructed curvature coordinates and a mass function from spherically symmetric canonical data. The key feature in our construction of a nonsingular canonical transformation to Kruskal variables, is the scaling of the curvature coordinate variables by the mass function rather than by the mass at left spatial infinity.Comment: 18 pages, no figure

On the resolution of the big bang singularity in isotropic Loop Quantum Cosmology

In contrast to previous work in the field, we construct the Loop Quantum Cosmology (LQC) of the flat isotropic model with a massless scalar field in the absence of higher order curvature corrections to the gravitational part of the Hamiltonian constraint. The matter part of the constraint contains the inverse triad operator which can be quantized with or without the use of a Thiemann- like procedure. With the latter choice, we show that the LQC quantization is identical to that of the standard Wheeler DeWitt theory (WDW) wherein there is no singularity resolution. We argue that the former choice leads to singularity resolution in the sense of a well defined, regular (backward) evolution through and beyond the epoch where the size of the universe vanishes. Our work along with that of the seminal work of Ashtekar, Pawlowski and Singh (APS) clarifies the role, in singularity resolution, of the three `exotic' structures in this LQC model, namely: curvature corrections, inverse triad definitions and the `polymer' nature of the kinematic representation. We also critically examine certain technical assumptions made by APS in their analysis of WDW semiclassical states and point out some problems stemming from the infrared behaviour of their wave functionsComment: 26 pages, no figure

The non-vanishing effect of detuning errors in dynamical decoupling based quantum sensing experiments

Characteristic dips appear in the coherence traces of a probe qubit when dynamical decoupling (DD) is applied in synchrony with the precession of target nuclear spins, forming the basis for nanoscale nuclear magnetic resonance (NMR). The frequency of the microwave control pulses is chosen to match the qubit transition but this can be detuned from resonance by experimental errors, hyperfine coupling intrinsic to the qubit, or inhomogeneous broadening. The detuning acts as an additional static field which is generally assumed to be completely removed in Hahn echo and DD experiments. Here we demonstrate that this is not the case in the presence of finite pulse-durations, where a detuning can drastically alter the coherence response of the probe qubit, with important implications for sensing applications. Using the electronic spin associated with a nitrogen-vacancy centre in diamond as a test qubit system, we analytically and experimentally study the qubit coherence response under CPMG and XY8 dynamical decoupling control schemes in the presence of finite pulse-durations and static detunings. Most striking is the splitting of the NMR resonance under CPMG, whereas under XY8 the amplitude of the NMR signal is modulated. Our work shows that the detuning error must not be neglected when extracting data from quantum sensor coherence traces