1,797 research outputs found

    Actuator and sensor placement in linear advection PDE with building system application

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    AbstractWe study the problem of actuator and sensor placement in a linear advection partial differential equation (PDE). The problem is motivated by its application to actuator and sensor placement in building systems for the control and detection of a scalar quantity such as temperature and contaminants. We propose a gramian based approach to the problem of actuator and sensor placement. The special structure of the advection PDE is exploited to provide an explicit formula for the controllability and observability gramian in the form of a multiplication operator. The explicit formula for the gramian, as a function of actuator and sensor location, is used to provide test criteria for the suitability of a given sensor and actuator location. Furthermore, the solution obtained using gramian based criteria is interpreted in terms of the flow of the advective vector field. In particular, the almost everywhere stability property of the advective vector field is shown to play a crucial role in deciding the location of actuators and sensors. Simulation results are performed to support the main results of this paper

    Noncommutative Chiral Anomaly and the Dirac-Ginsparg-Wilson Operator

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    It is shown that the local axial anomaly in 2−2-dimensions emerges naturally if one postulates an underlying noncommutative fuzzy structure of spacetime . In particular the Dirac-Ginsparg-Wilson relation on SF2{\bf S}^2_F is shown to contain an edge effect which corresponds precisely to the ``fuzzy'' U(1)AU(1)_A axial anomaly on the fuzzy sphere . We also derive a novel gauge-covariant expansion of the quark propagator in the form 1DAF=aΓ^L2+1DAa\frac{1}{{\cal D}_{AF}}=\frac{a\hat{\Gamma}^L}{2}+\frac{1}{{\cal D}_{Aa}} where a=22l+1a=\frac{2}{2l+1} is the lattice spacing on SF2{\bf S}^2_F, Γ^L\hat{\Gamma}^L is the covariant noncommutative chirality and DAa{\cal D}_{Aa} is an effective Dirac operator which has essentially the same IR spectrum as DAF{\cal D}_{AF} but differes from it on the UV modes. Most remarkably is the fact that both operators share the same limit and thus the above covariant expansion is not available in the continuum theory . The first bit in this expansion aΓ^L2\frac{a\hat{\Gamma}^L}{2} although it vanishes as it stands in the continuum limit, its contribution to the anomaly is exactly the canonical theta term. The contribution of the propagator 1DAa\frac{1}{{\cal D}_{Aa}} is on the other hand equal to the toplogical Chern-Simons action which in two dimensions vanishes identically .Comment: 26 pages, latex fil

    Hybrid Spectral-IRDx: Near-IR and Ultrasound Attenuation System for Differentiating Breast Cancer from Adjacent Normal Tissue

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    OBJECTIVE: While performing surgical excision for breast cancer (lumpectomy), it is important to ensure a clear margin of normal tissue around the cancer to achieve complete resection. The current standard is histopathology; however, it is time-consuming and labour-intensive requiring skilled personnel. METHOD: We describe a Hybrid Spectral-IRDx - a combination of the previously reported Spectral-IRDx tool with multimodal ultrasound and NIR spectroscopy techniques. We show how this portable, cost-effective, minimal-contact tool could provide rapid diagnosis of cancer using formalin-fixed (FF) and deparaffinized (DP) breast biopsy tissues. RESULTS: Using this new tool, measurements were performed on cancerous/fibroadenoma and its adjacent normal tissues from the same patients (N=14). The acoustic attenuation coefficient () and reduced scattering coefficient (s) (at 850, 940, and 1060 nm) for the cancerous/fibroadenoma tissues were reported to be higher compared to adjacent normal tissues, a basis of delineation. Comparing FF cancerous and adjacent normal tissue, the difference in s at 850 nm and 940 nm were statistically significant (p=3.17e-2 and 7.94e-3 respectively). The difference in between the cancerous and adjacent normal tissues for DP and FF tissues were also statistically significant (p=2.85e-2 and 7.94e-3 respectively). Combining multimodal parameters and s (at 940 nm) show highest statistical significance (p=6.72e-4) between FF cancerous/fibroadenoma and adjacent normal tissues. CONCLUSION: We show that Hybrid Spectral-IRDx can accurately delineate between cancerous and adjacent normal breast biopsy tissue. SIGNIFICANCE: The results obtained establish the proof-of-principle and large-scale testing of this multimodal breast cancer diagnostic platform for core biopsy diagnosis

    A comparative study of efficacy of argyreia speciosa and orlistat for their anti-obesity action in high fat diet induced obese rats

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    Background: To compare the anti-obesity action of Argyreia speciosa root extract with standard anti-obesity drug orlistat. Healthy Sprague-Dawley rats (100-200g, n=50) were obtained from the animal house. Dose of Orlistat was 32.4mg/kg/day and Dose of Argyreia speciosa root was 500mg/kg/day.Methods: Food induced obesity model was used. Following parameters were evaluated: Total Cholesterol (mg/dl), Triglyceride (mg/dl), HDL-cholesterol (mg/dl), LDL cholesterol (mg/dl), atherogenic index, serum lipase (U/L). Analysis was done by one way ANOVA followed by post-hoc test and Graph Pad Prism version 5.00 was used for the analysis.Results: Total cholesterol, triglcerides, LDL cholesterol and Atherogenic index was significantly lesser in the rats fed with CD+O group and CD+ASE group than in the animals from CD group (p<0.05). It was also significantly lesser in the rats fed with CD+O+ASE than in the animals from CD group (p<0.05). HDL cholesterol was significantly greater in the rats fed with CD+O group and CD+ASE group than in the animals from CD group (p<0.05). It was also significantly greater in the rats fed with CD+O+ASE than in the animals from CD group (p<0.05).Conclusions: ASE significantly reduces total cholesterol (mg/dl), triglyceride (mg/dl), LDL cholesterol (mg/dl) and atherogenic index, it significantly increases HDL- cholesterol (mg/dl) and it is comparable to orlistat. Thus the anti-obesity action of ASE is comparable to orlistat

    Polyurethane Based Inhibition for High Flame Temperature Nitramine Based Composite Modified Double Base propellant

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    The findings for polypropylene glycol (PPG) and hydroxyl-terminated polybutadiene (HTPB)-based inhibition systems are reported. These findings established that the inhibition system comprising HTPB-IPDI-IDP binder and Sb/sub 2/O/sub 3/-C black filler is most suitable for advanced nitramine-based composite modified double-base propellants in terms of mechanical properties and processibility. The promising composition was characterised for glass-transition behaviour and propellant-inhibition bond strength. Propellant grains inhibited with selected formulations were subjected to static evaluation at extreme temperatures and limited aging studies to obtain data of practical value

    Study of fetomaternal outcome in pre-eclampsia at tertiary care centres, South Gujarat

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    Background: Hypertensive disorders are among the most common medical disorder during pregnancy and continue to be a serious challenge in obstetric practice. It affects about 7-15% of all gestations. In India it accounts for the third most important cause of maternal mortality. Aim if this study was to study the prevalence of pre-eclampsia and feto-maternal outcome in cases of pre-eclampsia. Methods: This was a descriptive observational study conducted over a period from February 2019 to July 2021. This study enrolled 106 cases of pre-eclampsia, cases were selected by inclusion and exclusion criteria, data were entered and analysed by using SPSS version 20. Results: A total of 106 patients were analysed. It was observed that it was more common in age group of 26 to 30 years 51%, 56% were unbooked patients. Maximum number of patients were primigravida 60%, 96% patients were from lower socioeconomic class, 37% patients had normal vaginal delivery, 63% had caesarean delivery. The most common maternal complication was eclampsia (12%), HELLP Syndrome 12%, abruptio occurred in 8% of patients. Maternal mortality occurred in 4 cases. Out of 106 babies 37 (34.93%) babies had normal outcome while 29% (27.35%) had low birth weight, 16 (15.09%) babies were IUGR, 15 (14.5%) babies were IUFD, 7 (6.6%) babies had RDS and 2 (1.8%) babies were stillbirth 40 (44.94%) babies were admitted in NICU. Conclusions: This study concludes that foetal and maternal outcome were markedly affected by pre-eclampsia and also the grave complications were more common in pre-eclampsia. So proper antenatal care, early diagnosis of pre-eclampsia and timely intervention will decrease maternal perinatal morbidity and mortality

    Iterative Approximate Consensus in the presence of Byzantine Link Failures

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    This paper explores the problem of reaching approximate consensus in synchronous point-to-point networks, where each directed link of the underlying communication graph represents a communication channel between a pair of nodes. We adopt the transient Byzantine link failure model [15, 16], where an omniscient adversary controls a subset of the directed communication links, but the nodes are assumed to be fault-free. Recent work has addressed the problem of reaching approximate consen- sus in incomplete graphs with Byzantine nodes using a restricted class of iterative algorithms that maintain only a small amount of memory across iterations [22, 21, 23, 12]. However, to the best of our knowledge, we are the first to consider approximate consensus in the presence of Byzan- tine links. We extend our past work that provided exact characterization of graphs in which the iterative approximate consensus problem in the presence of Byzantine node failures is solvable [22, 21]. In particular, we prove a tight necessary and sufficient condition on the underlying com- munication graph for the existence of iterative approximate consensus algorithms under transient Byzantine link model. The condition answers (part of) the open problem stated in [16].Comment: arXiv admin note: text overlap with arXiv:1202.609

    Functional intercomparison of intraoperative radiotherapy equipment – Photon Radiosurgery System

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    BACKGROUND: Intraoperative Radiotherapy (IORT) is a method by which a critical radiation dose is delivered to the tumour bed immediately after surgical excision. It is being investigated whether a single high dose of radiation will impart the same clinical benefit as a standard course of external beam therapy. Our centre has four Photon Radiosurgery Systems (PRS) currently used to irradiate breast and neurological sites. MATERIALS AND METHODS: The PRS comprises an x-ray generator, control console, quality assurance tools and a mobile gantry. We investigated the dosimetric characteristics of each source and its performance stability over a period of time. We investigated half value layer, output diminution factor, internal radiation monitor (IRM) reproducibility and depth-doses in water. The half value layer was determined in air by the broad beam method, using high purity aluminium attenuators. To quantify beam hardening at clinical depths, solid water attenuators of 5 and 10 mm were placed between the x-ray probe and attenuators. The ion chamber current was monitored over 30 minutes to deduce an output diminution factor. IRM reproducibility was investigated under various exposures. Depth-dose curves in water were obtained at distances up to 35 mm from the probe. RESULTS: The mean energies for the beam attenuated by 5 and 10 mm of solid water were derived from ICRU Report 17 and found to be 18 and 24 keV. The average output level over a period of 30 minutes was found to be 99.12%. The average difference between the preset IRM limit and the total IRM count was less than 0.5%. For three x-ray sources, the average difference between the calculated and actual treatment times was found to be 0.62% (n = 30). The beam attenuation in water varied by approximately 1/r(3). CONCLUSION: The x-ray sources are stable over time. Most measurements were found to lie within the manufacturer's tolerances and an intercomparison of these checks suggests that the four x-ray sources have similar performance characteristics
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