40 research outputs found

    Guidance Scheme for Solid Propelled Vehicle during Atmospheric Phase

    Get PDF
    Strategic ballistic missiles are the long-range missiles designed to intercept stationary, defined targets. Guidance is in the boost phase which represents only a small fraction of the total timeof flight of the missile. A missile has to be guided and steered to the required position and velocity states at the end of the boost phase. The problem of guiding a vehicle in atmospheric phase in the presence of drag and lift, poses a challenge for the designer. This paper describes an energy management guidance scheme for guiding the vehicle in atmospheric phase of theflight. The estimated drag is taken care of by the ghidance scheme. Uncertainty in velocity due to drag or impulse variation at the end of the boost phase are corrected by an augmented velocity package. A closed-loop guidance scheme has been used during this phase also. A ballistic reentry has been considered for this design study

    Pathogenesis of Cholera: Recent Prospectives in Rapid Detection and Prevention of Cholera

    Get PDF
    Cholera, also known as “blue death” is a potentially epidemic and life-threatening secretory diarrhea characterized by numerous voluminous watery stools, often accompanied by vomiting and resulting in hypovolemic shock and acidosis. The causative agent of this water-borne disease belongs to certain members of the species Vibrio cholerae (V. cholerae) which can also cause mild or unapparent infections. V. cholerae is a facultative anaerobic, Gram-negative bacilli, which possess the characteristic feature of darting motility under wet-mound preparations. Other members of the species may occasionally cause isolated outbreaks of milder diarrhea, whereas others—the vast majority—are free-living and not associated with disease. The emergence of new, virulent, drug-resistant strains of Vibrio is the main cause of protracted outbreaks leading to high fatality rates. The subsequent loss of fluid volume causes a drop in blood pressure and circulatory shock. If the patient remains untreated, they become progressively weaker, sometimes to the point of death, within 12–24 h of the onset of symptoms. The severity and fatality of the disease depend on the strain of Vibrio. The cholera toxin-producing (CT-producing) V. cholerae manifests the most fatal disease known as cholera gravis. Throughout most of the twentieth century, cholera was caused by V. cholerae of the O1 serogroup, and the disease was largely confined to Asia and Africa. The emergence of a pandemic in 1992 was caused by an unknown serogroup of V. cholerae (O139) wherein the targets were India and Bangladesh. The pathogenesis and virulence of the bacteria are due to an enterotoxin it produces—cholera toxin (CT). The mechanism of action of CT is discussed in this chapter at a later stage. Attempts have been made to produce vaccines through a number of trial-and-error methods, and still the possibility of an effective vaccine which gives a good prophylactic measure is under consideration. The identification of the bacteria as well as toxin detection is one of the main elements in the clinical microbiology field. The identification and confirmation of this epidemic disease commend from the morphological identification of Vibrio and end with serotyping and biotyping in addition to toxin detection by various means of assays—both in vitro and in vivo. This chapter will cover all of the mentioned areas of clinical microbiology with respect to cholera infection in addition to the recent outbreaks and epidemics which occurred across the globe

    Power Spectral Density Computation and Dominant Frequencies Identification from the Vibration Sensor Output under Random Vibration Environment

    Get PDF
    The objective of the modal and spectral analysis is to determine the vibration characteristics of structures such as natural frequencies, dominant frequencies and mode shapes. Such modal and spectral analyses have major relevance to the study of the dynamic properties of the structures undergoing dynamic vibration. Methods for the estimation of the power spectral density and identification of the dominant frequencies from the sensor responses under random vibrating environment are presented in this paper. Periodogram using FFT, Welch Method and MUSIC algorithm are used to analyse the known frequency sinusoids with additive white noise and output of the vibration sensor mounted on the test object. The resultant spectra obtained using the methods and their corresponding errors with the reference spectrum are analysed. The Welch method is further studied with three different windows, namely, Hann, Hamming and Blackman-Harris and with three different overlapping criteria viz. 0%, 25% and 50%. The same algorithm and methodology were adopted and compared in two different platforms: Mathematical Model Simulation and Hardware-In-Loop-Simulation. It is observed from the results that Welch Method with 25% overlap used in combination either with Hann or Blackman-Harris window yields more accurate results, compared to other combinations. Also, 25% overlap provides better execution time trade-off compared to 50% overlap

    An Architecture for On board Frequency Domain Analysis of Launch Vehicle Vibration Signals

    Get PDF
    The dynamic properties of the airborne structures plays a crucial role in the stability of the vehicle during flight. Modal and spectral behaviour of the structures are simulated and analysed. Ground tests are carried out with environmental conditions close to the flight conditions, with some assumptions. Subsequently, based on the flight telemetered data, the on-board mission algorithm and the auto-pilot filter coefficients are fine tuned. An attempt is made in this paper to design a novel architecture for analysing the modal and spectral random vibration signals on-board the flight vehicle and to identify the dominant frequencies. Based on the analysed results, the mission mode algorithm and the filter coefficients can be fine tuned on-board for better effectiveness in control and providing more stability. Three types of windows viz. Hann, Hamming and Blackman-Harris are configured with a generalised equation using FIR filter structure. The overlapping of the input signal data for better inclusiveness of the real-time data is implemented with BRAM. The domain conversion of the data from time domain to frequency domain is carried out with FFT using Radix-2 BF architecture. The FFT output data are processed for calculating the power spectral density. The dominant frequency is identified using the array search method and Goldschmidt algorithm is utilised for the averaging of the PSDs for better precision. The proposed architecture is synthesised, implemented and tested with both Synthetic and doppler signal of 300 Hz spot frequency padded with Gaussian white noise. The results are highly satisfactory in identifying the spot frequency and generating the PSD array

    Online Trajectory Reshaping for a Launch Vehicle to Minimize the Final Error Caused by Navigation and Guidance

    Get PDF
    Autonomous launch vehicles, once lifted off from the launch pad, equipped with an onboard intelligence which aids in achieving the mission objectives with high accuracy. The accuracy of the mission depends basically on navigation and guidance errors caused at burnout condition, after which the vehicle follows an elliptical path upto impact. The paper describes how to handle the final impact and injection error caused by these navigation and guidance errors. In the current work the initial burnout conditions are tuned and corrected such that the terminal impact point is achieved within the desired tolerance bounds. A two point boundary value problem is solved using the gradient method, for determining the impact errors. The algorithm is validated by simulation studies for various burnout conditions.Defence Science Journal, 2013, 63(3), pp.254-261, DOI:http://dx.doi.org/10.14429/dsj.63.241

    Teaching Internationally, Learning Collaboratively: Intercultural Perspectives on Information Literacy and Metaliteracy (IPILM)

    Get PDF
    Intercultural Perspectives on Information Literacy and Metaliteracy (IPILM) is a discourse- oriented learning environment that engages students from diverse cultural backgrounds to participate in collaborative knowledge construction. The objective is to evolve a thematic approach to course design that includes elements of open pedagogy, information literacy, and metaliteracy. IPILM invites participation from educators and learners from around the world and has witnessed an increase in participating countries. This paper describes the concept of IPILM and demonstrates the implementation of this approach in practice. The initiative was well received by students and is both feasible and sustainable as an intercultural learning endeavor. IPILM is an ongoing project and a work in progress that is an adaptable model which may be transferred to disparate fields of teaching and learning or adopted by international communities of instructors

    Do guidelines for treating chest disease in children use Cochrane Reviews effectively?: a systematic review

    Get PDF
    Cochrane Reviews summarise best evidence and should inform guidelines. We assessed the use of Cochrane Reviews in the UK guidelines for paediatric respiratory disease. We found 21 guidelines which made 1025 recommendations, of which 96 could be informed by a Cochrane Review. In 38/96 recommendations (40%), some or all of the relevant Cochrane Reviews were not cited. We linked recommendations to 140 Cochrane Reviews. In 37/140 (26%) cases, the guideline recommendation did not fully agree with the Cochrane Review. Guideline developers may fail to use Cochrane Reviews or may make recommendations which are not in line with best evidence

    scFASTCORMICS: A Contextualization Algorithm to Reconstruct Metabolic Multi-Cell Population Models from Single-Cell RNAseq Data

    Get PDF
    Tumours are composed of various cancer cell populations with different mutation profiles, phenotypes and metabolism that cause them to react to drugs in diverse manners. Increasing the resolution of metabolic models based on single-cell expression data will provide deeper insight into such metabolic differences and improve the predictive power of the models. scFASTCORMICS is a network contextualization algorithm that builds multi-cell population genome-scale models from single-cell RNAseq data. The models contain a subnetwork for each cell population in a tumour, allowing to capture metabolic variations between these clusters. The subnetworks are connected by a union compartment that permits to simulate metabolite exchanges between cell populations in the microenvironment. scFASTCORMICS uses Pareto optimization to simultaneously maximise the compactness, completeness and specificity of the reconstructed metabolic models. scFASTCORMICS is implemented in MATLAB and requires the installation of the COBRA toolbox, rFASTCORMICS and the IBM CPLEX solver

    Moral Injury and Moral Resilience in Health Care Workers during COVID-19 Pandemic.

    Get PDF
    BACKGROUND: The 2019 coronavirus (COVID-19) pandemic placed unprecedented strains on the U.S. health care system, putting health care workers (HCWs) at increased risk for experiencing moral injury (MI). Moral resilience (MR), the ability to preserve or restore integrity, has been proposed as a resource to mitigate the detrimental effects of MI among HCWs. OBJECTIVES: The objectives of this study were to investigate the prevalence of MI among HCWs, to identify the relationship among factors that predict MI, and to determine whether MR can act as buffer against it. DESIGN: Web-based exploratory survey. SETTING/SUBJECTS: HCWs from a research network in the U.S. mid-Atlantic region. MEASUREMENTS: Survey items included: our outcome, Moral Injury Symptoms Scale–Health Professional (MISS-HP), and predictors including demographics, items derived from the Rushton Moral Resilience Scale (RMRS), and ethical concerns index (ECI). RESULTS: Sixty-five percent of 595 respondents provided COVID-19 care. The overall prevalence of clinically significant MI in HCWs was 32.4%; nurses reporting the highest occurrence. Higher scores on each of the ECI items were significantly positively associated with higher MI symptoms (p < 0.05). MI among HCWs was significantly related to the following: MR score, ECI score, religious affiliation, and having ≥20 years in their profession. MR was a moderator of the effect of years of experience on MI. CONCLUSIONS: HCWs are experiencing MI during the pandemic. MR offers a promising individual resource to buffer the detrimental impact of MI. Further research is needed to understand how to cultivate MR, reduce ECI, and understand other systems level factors to prevent MI symptoms in U.S. HCWs

    Do guidelines for treating chest disease in children use Cochrane Reviews effectively?: a systematic review

    Get PDF
    Cochrane Reviews summarise best evidence and should inform guidelines. We assessed the use of Cochrane Reviews in the UK guidelines for paediatric respiratory disease. We found 21 guidelines which made 1025 recommendations, of which 96 could be informed by a Cochrane Review. In 38/96 recommendations (40%), some or all of the relevant Cochrane Reviews were not cited. We linked recommendations to 140 Cochrane Reviews. In 37/140 (26%) cases, the guideline recommendation did not fully agree with the Cochrane Review. Guideline developers may fail to use Cochrane Reviews or may make recommendations which are not in line with best evidence
    corecore