1,116 research outputs found

    Refractive indices, density and order parameter of some technologically important liquid crystalline mixtures

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    Temperature variation of the refractive indices, birefringence, density and order parameter of liquid crystalline mixtures E7, E8, N10 and PCH-1132 are reported. The birefringence of PCH-1132 is found to be abnormally low compared to other mixtures

    Refractive indices, density and order parameter of some liquid crystals

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    The temperature variation of the refractive indices (no, ne) and density are reported for two liquid crystals. The order parameter is evaluated by both Vuks' and Neugebauer's approaches. The possible sources of error in evaluating the order parameter from refractive indices measurements have been discussed. The contradictory behavior of Δ n and ΔX during the nematic-smectic B phase transition of HBT has been explained on the basis of polydomain formation and the order parameter in the SB phase is estimated. The order parameter of two liquid crystals, HBT and OBT, is also evaluated by NMR measurements, confirming the polydomain formation in the SB phase of HBT

    Refractive indices, density and order parameter of two liquid crystals HBT and OBT

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    The temperature variation of refractive indices (ne ne), birefringence (δn), density (ρ) and order parameter (S) of two liquid crystals, namely, N-(p-hexyloxybenzylidene)-p-toluidine (HBT) and N-(p-octyloxybenzylidene)-p-toluidine (OBT) are reported in the smectic (SA in OBT and SB in HBT), nematic and isotropic phases. For accurate measurement of δn, the wedge method was modified to eliminate the need to measure the wedge angle. Density measurements indicate that the smectic-nematic and nematic-isotropic phase transitions in these materials are of first order. Using refractive index values and the density data, the internal field factors (γe, γo), the ratio of principal polarizabilities f(=αeαo) and the order parameter, S, have been evaluated and their temperature dependence discussed in the light of molecular geometry. The order parameter has been determined using the isotropic internal field model (Vuks approach) and the anisotropic internal field model (Neugebauer's approach). The S values determined using these two models agree in the nematic phase but differ considerably in the smectic phase

    Case report of a successful term pregnancy following renal transplantation

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    Pregnancy with renal disease is associated with high risk for both mother and fetus with adverse outcomes. Criteria for considering pregnancy in renal transplanted patients include good post-transplant health for 2 years, stable allograft function with a serum creatinine <1.5 mg/dl, absence of rejection, control of blood pressure, absence of proteinuria. Authors report a case of 26-year-old, primigravida had renal transplantation done in NRI Medical College and treated with immunosuppressive therapy with tablets Tacrolimus 1mg twice daily, Azathioprine 50mg twice daily, Prednisolone 10mg once daily and continued till delivery. Developed gestational hypertension treated with tablet Amlodipine 5mg once daily. Elective caesarean section done for contracted pelvis. Post-natal period was uneventful and discharged on immunosuppressive therapy and contraceptive advice. Post-renal transplantation pregnancy should have multidisciplinary approach for. With close medical and obstetric follow up, successful outcome for both mother and infant is possible

    Two quantum analogues of Fisher information from a large deviation viewpoint of quantum estimation

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    We discuss two quantum analogues of Fisher information, symmetric logarithmic derivative (SLD) Fisher information and Kubo-Mori-Bogoljubov (KMB) Fisher information from a large deviation viewpoint of quantum estimation and prove that the former gives the true bound and the latter gives the bound of consistent superefficient estimators. In another comparison, it is shown that the difference between them is characterized by the change of the order of limits.Comment: LaTeX with iopart.cls, iopart12.clo, iopams.st

    Assessing the impact of soil moisture-temperature coupling on temperature extremes over the Indian region

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    While previous model sensitivity studies have mainly focused on discerning the soil moisture-precipitation feedback processes over the Indian region, the present study investigates the impact of soil moisture-temperature (SM-T) coupling on the temperature extremes (ExT) using the high-resolution (~60 km) model simulations. These simulations include the control and soil moisture (SM) sensitivity experiments (DRY-SM and WET-SM) initialized by perturbing (decreasing/increasing) SM from the historical (HIST: 1951-2010) and future 4K warming (FUT: 2051-2100) control runs. The analysis identifies the transitional regions of north-central India (NCI) as the hotspot of strong SM-T coupling. Over NCI, the HIST experiment shows an occurrence of 4-5 extreme events per year, with an average duration of 5-6 days per event and intensity exceeding 46oC. Whereas, FUT estimates indicate relatively severe, long-lasting, and more frequent extreme events. The SM sensitivity experiments reveal the significant influence of SM-T coupling on the ExT over NCI in both historical and future climates. We find that the DRY-SM results in significant enhancement of frequency, duration and intensity of ExT, in contrast to WET-SM. We note that the difference between DRY-SM and WET-SM 50-year return value of the block maxima GEV fit can reach upto 1.25oC and 3oC for historical and future climate, respectively. The enhanced (reduced) extreme temperature conditions in DRY-SM (WET-SM) simulation are caused by the intensification (abridgement) of sensible heat flux by limiting (intensifying) available total energy for evaporative cooling due to faster (slower) dissipation of positive soil moisture anomalies (also called as soil moisture memory). In addition, the influence of SM on ExT over NCI is found to be larger during the post-monsoon season as compared to the pre-monsoon and monsoon seasons.Comment: 60 pages, 13 figure

    Droplet actuation induced by coalescence: experimental evidences and phenomenological modeling

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    This paper considers the interaction between two droplets placed on a substrate in immediate vicinity. We show here that when the two droplets are of different fluids and especially when one of the droplet is highly volatile, a wealth of fascinating phenomena can be observed. In particular, the interaction may result in the actuation of the droplet system, i.e. its displacement over a finite length. In order to control this displacement, we consider droplets confined on a hydrophilic stripe created by plasma-treating a PDMS substrate. This controlled actuation opens up unexplored opportunities in the field of microfluidics. In order to explain the observed actuation phenomenon, we propose a simple phenomenological model based on Newton's second law and a simple balance between the driving force arising from surface energy gradients and the viscous resistive force. This simple model is able to reproduce qualitatively and quantitatively the observed droplet dynamics

    Asymptotic estimation theory for a finite dimensional pure state model

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    The optimization of measurement for n samples of pure sates are studied. The error of the optimal measurement for n samples is asymptotically compared with the one of the maximum likelihood estimators from n data given by the optimal measurement for one sample.Comment: LaTeX, 23 pages, Doctoral Thesi

    Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

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    A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)

    Harmonic Analysis of Boolean Networks: Determinative Power and Perturbations

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    Consider a large Boolean network with a feed forward structure. Given a probability distribution on the inputs, can one find, possibly small, collections of input nodes that determine the states of most other nodes in the network? To answer this question, a notion that quantifies the determinative power of an input over the states of the nodes in the network is needed. We argue that the mutual information (MI) between a given subset of the inputs X = {X_1, ..., X_n} of some node i and its associated function f_i(X) quantifies the determinative power of this set of inputs over node i. We compare the determinative power of a set of inputs to the sensitivity to perturbations to these inputs, and find that, maybe surprisingly, an input that has large sensitivity to perturbations does not necessarily have large determinative power. However, for unate functions, which play an important role in genetic regulatory networks, we find a direct relation between MI and sensitivity to perturbations. As an application of our results, we analyze the large-scale regulatory network of Escherichia coli. We identify the most determinative nodes and show that a small subset of those reduces the overall uncertainty of the network state significantly. Furthermore, the network is found to be tolerant to perturbations of its inputs
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