5,857 research outputs found

    Formulation And In Vitro/In Vivo Evaluation Of Olmesartan Medoxomil Solid Dispersions Incorporated E/R Trilayer Matrix Tablets By Geomatrix

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    An attempt has been made to develop and optimize an novel anti hypertensive trilayered controlled release matrix tablets incorporated with Olmesartan medoxomil solid dispersion prepared by direct compression and consisted of middle active layer with different grades of hydroxypropylmethylcellulose (HPMC), guar gum, ethyl cellulose. Upper and lower layers are prepared with Carnauba wax, guar gum and sodium CMC. The developed drug delivery system provided prolonged drug release rates over a period of 24 h. The release profile of the optimized formulation (HF14) was described by the Zero-order and Higuchi model. In-vivo bioavailability studies were carried out with the optimized formulation (HF14) and reference standard A fair correlation between the dissolution profile and bioavailability for the optimized formulation was observed. The results indicate that the approach used could lead to a successful development of a trilayer extended release formulation up to 24h. These results also demonstrated that the Olmesartan solid dispersion incorporated trilayer tablets shown more bioavailability because of its conversion from crystalline to amorphous form

    Dispersive Wave Analysis – Method and Applications

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    A technique for estimating the dispersion characteristics of propagating waves as measured by an array is detailed. The technique consists of bandpass filtering the data through a filterbank and then processing the filtered waveforms non-dispersively. The results can show the dispersion of the entire time series or be parsed in time to analyze the dispersion characteristics of any section of the time series. Processing LWD field data shows that this method can extract dispersion characteristics over a broadband of frequencies and with low amplitude signals. Both the field data and laboratory scale data show that multiple modes present over the same frequency band can be identified.Halliburton CompanyMassachusetts Institute of Technology. Earth Resources LaboratoryMassachusetts Institute of Technology. Borehole Acoustics and Logging Consortiu

    Bandwidth Recycling using Variable Bit Rate

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    IEEE 802.16 standard was designed to support the bandwidth demanding applications with quality of service (QoS). Bandwidth is reserved for each application to ensure the QoS. For variable bit rate (VBR) applications, however, it is difficult for the subscriber station (SS) to predict the amount of incoming data. To ensure the QoS guaranteed services, the SS may reserve more bandwidth than its demand. As a result, the reserved bandwidth may not be fully utilized all the time. In this paper, we propose a scheme, named Bandwidth Recycling, to recycle the unused bandwidth without changing the existing bandwidth reservation. The idea of the proposed scheme is to allow other SSs to utilize the unused bandwidth when it is available. Thus, the system throughput can be improved while maintaining the same QoS guaranteed services. Mathematical analysis and simulation are used to evaluate the proposed scheme. Simulation and analysis results confirm that the proposed scheme can recycle 35% of unused bandwidth on average. By analyzing factors affecting the recycling performance, three scheduling algorithms are proposed to improve the overall throughput. The simulation results show that our proposed algorithm improves the overall throughput by 40% in a steady network. Keywords: WiMAX, IEEE 802.16, Bandwidth Recyclin

    Development of efficient techniques for ASR System for Speech Detection and Recognization system using Gaussian Mixture Model- Universal Background Model

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    Some practical uses of ASR have been implemented, including the transcription of meetings and the usage of smart speakers. It is the process by which speech waves are transformed into text that allows computers to interpret and act upon human speech. Scalable strategies for developing ASR systems in languages where no voice transcriptions or pronunciation dictionaries exist are the primary focus of this work. We first show that the necessity for voice transcription into the target language can be greatly reduced through cross-lingual acoustic model transfer when phonemic pronunciation lexicons exist in the new language. Afterwards, we investigate three approaches to dealing with languages that lack a pronunciation lexicon. Secondly, we have a look at the efficiency of graphemic acoustic model transfer, which makes it easy to build pronunciation dictionaries. Thesis problems can be solved, in part, by investigating optimization strategies for training on huge corpora (such as GA+HMM and DE+HMM). In the training phase of acoustic modelling, the suggested method is applied to traditional methods. Read speech and HMI voice experiments indicated that while each data augmentation strategy alone did not always increase recognition performance, using all three techniques together did. Power normalised cepstral coefficient (PNCC) features are tweaked somewhat in this work to enhance verification accuracy. To increase speaker verification accuracy, we suggest employing multiple “Gaussian Mixture Model-Universal Background Model (GMM-UBM) and SVM classifiers”. Importantly, pitch shift data augmentation and multi-task training reduced bias by more than 18% absolute compared to the baseline system for read speech, and applying all three data augmentation techniques during fine tuning reduced bias by more than 7% for HMI speech, while increasing recognition accuracy of both native and non-native Dutch speech

    NIH COBRE-Natural Products Neuroscience Chemistry Services Under Chemistry and DM-PK CORE Facility

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    Department/Unit poster (BioMolecular Sciences). Corresponding author: Rama S. Gadepalli ([email protected])https://egrove.olemiss.edu/pharm_annual_posters_2022/1008/thumbnail.jp

    Scanning Electron Probe Microanalysis

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    Scanning electron probe microanalysis has grown over the pastthree decades into a powerful technique for the microchemicalcharacterisation of materials. This paper describes the principles andvarious features of a typical microanalyser, and illustrates its uniquecapabilities in the study of materials by means of selected case histories

    A NEW SPEECH ENHANCEMENT TECHNIQUE USING PERCEPTUAL CONSTRAINED SPECTRAL WEIGHTING FACTORS

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    This paper deals with musical noise result from perceptual speech enhancement type algorithms and especially wiener filtering. Although perceptual speech enhancement methods perform better than the non perceptual methods, most of them still return annoying residual musical noise. This is due to the fact that if only noise above the noise masking threshold is filtered then noise below the noise masking threshold can become audible if its maskers are filtered. It can affect the performance of perceptual speech enhancement method that process audible noise only. In order to overcome this drawback here proposed a new speech enhancement technique. It aims to improve the quality of the enhanced speech signal provided by perceptual wiener filtering by controlling the latter via a second filter regarded as a psychoacoustically motivated weighting factor. The simulation results shows that the performance is improved compared to other perceptual speech enhancement method

    Geomechanical Modeling of In-Situ Stresses Around a Borehole

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    In this paper, we present a modelling of the in-situ stress state associated with the severe hole enlargement of a wellbore. Geomechanical information is relevant to assure wellbore stability, i.e., to prevent damages in the formation and later on, the casing. Many of the drilling parameters, as mud weight or the optimal orientation of the borehole, require some knowledge of the mechanical behaviour of the rock. The lack of these kind of data in exploratory areas, where there are usually insufficient constraints for the geological model, increases even more the risk, hence the costs. The present model uses the concepts of poroelasticity theory to compute the stationary 2D, brittle response of the formation around a borehole that is submitted to effective compressive horizontal stresses. The numerical solution is obtained using a finite element approximation. The initial stress state at the far field was estimated combining a frictional-failure theory with the observations of dipmeter caliper in a particular borehole that presents elongations in a preferential direction. The direction and relative extension of the observed breakouts at a particular depth are modelled successfully using formation realistic parameters and dimensions, although the exact shape of the borehole (at all angles) was unknown. For the particular case study, the orientation of the breakout is NE-SW, at about 82 degrees azimuth. Therefore, the maximum horizontal stress lies at approximately 350 degrees azimuth. The ratios of horizontal principal stresses to vertical stress that best honor the observations are SHmax = 2.3Sv and Shmin = 1.7Sv. The compressive strength necessary for the rock to fail, as indicated by the caliper data under this stress field, is about 140 MPa.Massachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laborator
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