562 research outputs found
Measurements in the near-wall region of a relaxing three-dimensional low speed turbulent air boundary layer
An experimental investigation was conducted at selected locations of the near-wall region of a three dimensional turbulent air boundary layer relaxing in a nominally zero external pressure gradient behind a transverse hump (in the form of a 30 deg swept, 5-foot chord wing-type model) faired into the side wall of a low speed wind tunnel. Wall shear stresses measured with a flush-mounted hot-film gage and a sublayer fence were in very good agreement with experimental data obtained with two Preston probes. With the upstream unit Reynolds number held constant at 325,000/ft. approximately one-fourth of the boundary layer thickness adjacent to the wall was surveyed with a single rotated hot-wire probe mounted on a specially designed minimum interference traverse mechanism. The boundary layer (approximately 3.5 in thick near the first survey station where the length Reynolds number was 5.5 million) had a maximum crossflow velocity ratio of 0.145 and a maximum crossflow angle of 21.875 deg close to the wall
A three-dimensional turbulent boundary layer undergoing transverse strain and streamwise pressure gradient
Results from an experimental investigation designed to provide data on both mean and turbulence quantities in the axisymmetric, swirling boundary layer (with and without pressure gradient) flowing over a stationary cylinder downstreams of a spinning cylindrical section are presented. The pressure gradient was introduced into the flow field by a 25.4 mm-high, forward-facing, circular step mounted on the stationary cylinder, the step height being nearly equal to the thickness of the approaching boundary layer. All the measurements were made at a nominal upstream reference Reynolds number of 2.4 x 10 to the 6th power/m (corresponding to an upstream reference velocity of 36 to 37 m/sec) with the rotation of the spinner set to make its peripheral speed equal the reference velocity. The data reported included measurements of surface pressure and the mean surface shear-stress vector taken with a miniature, directional, surface-fence gage. These measurements were supplemented by oil-flow visualization studies of the stationary cylinder. The data indicates that the streamwise pressure gradient controls the development of the streamwise component of wall shear, but leaves the peripheral component of wall shear practically unaffected
Prospective study of fine needle aspiration cytology of clinically palpable breast lump with histopathological correlation
Background and objectives: This study was conducted to compare the diagnostic accuracy of fine needle aspiration cytology in differentiating the benign and malignant lesions of palpable breast lump with histopathological correlation and also to study the accuracy of the needle tip localizing the tumor during fine needle aspiration cytology procedure.Methods: Two years prospective study was conducted in our institution and in that 100 patients underwent fine needle aspiration cytology of the palpable breast lump after thorough physical examination. The cytological diagnosis was classified in to 3 groups benign, suspicious and malignant. After this reporting all the patients were later subjected to open/excision biopsy and its histopathological confirmation. Later diagnostic accuracy of cytology reporting was compared with that of histopathology. Accuracy of the needle tip in localizing the tumor in fine needle aspiration cytology was also studied by comparing the normal glandular cell aspirate with tumor cell aspirate. Repeat cytology was carried out before open/excision biopsy if the pathologist reports the cytology slide as “inadequate”.Results: We had accuracy rate of 100% for benign lesion and 93.10% for malignant lesion with false negative rate of 6.9% and false positive rate of zero with fine needle aspiration cytology in the diagnosis of palpable breast lump. The overall sensitivity of fine needle aspiration in diagnosing the palpable breast lump is 93.10%, specificity is 100%, positive predictive value is 100% and negative predictive value is 90.47%. Since inadequate sampling rate is 2% in our study, the accuracy rate of needle tip in localizing the tumor in fine needle aspiration cytology is 98%.Conclusion: Since our diagnostic accuracy rate and predictive values are very high and comparable to any other published series it can be advised that the patients in which fine needle aspiration cytology is unequivocally diagnostic for cancer can be managed directly by mastectomy (or any other definitive therapy). A diagnosis of suspicious for cancer must be confirmed by an open biopsy or intraoperative frozen section or rapid hemotoxyline and eosine staining (depending on availability). Since the accuracy of the needle tip in localizing the lump is very high (98%), the diagnostic accuracy of fine needle aspiration cytology can be increased by performing repeat aspiration on the lump for which previously being reported as inadequate or unsatisfactory sampling before advising for open biopsy
Validation of a new ovarian malignancy suspicion index for preoperative evaluation of adnexal masses
Background: The currently available ovarian malignancy probability scores incorporate biochemical markers such as CA 125 (Carbohydrate Antigen 125), which is not routinely available in peripheral centers. There is a need for tumour marker independent prediction model to differentiate malignant ovarian masses from their benign counterparts in order to plan appropriate surgery. To formulate and prospectively validate a new Ovarian Malignancy Suspicion Index (OMSI) independent of serum CA 125 level, in preoperative evaluation of adnexal masses admitted for surgery.Methods: This was a combined retrospective and prospective cohort study conducted in a tertiary referral hospital over a period of one and half years. Retrospective sample included 100 subjects who had undergone surgery for adnexal masses and who had definite histopathological report. Detailed data were obtained with respect to age, menopausal status, sonographic findings including solid areas, ascites, mean diameter, bilateralism, and presence of septa. A logistic multivariate regression analysis was carried out to find the best prediction score (OMSI - Ovarian Malignancy Suspicion Index). This model was further evaluated prospectively in 60 subjects for its diagnostic ability to identify benign and malignant ovarian pathology.Results: OMSI at the cut off value of 3.9 differentiated effectively malignant ovarian mass from benign variety with a good diagnostic performance (Sensitivity 100%, Specificity 90.5%, Positive Predictive Value 81.8% and Negative Predictive Value 100%) as good as currently recommended RMI (Risk Malignancy Index) score. It was also found that OMSI > 3.9 was associated with positive ultrasound evidence for ovarian malignancy such as presence of thick septae (90%), solid areas within the tumour (93.8%), papillary projections (100%), bilaterality (90%) and ascites (100%).Conclusions: This study shows that it is possible to derive ovarian malignancy prediction model such as OMSI without including CA 125 with diagnostic ability in par with risk scoring systems such as WHO recommended RMI. Using this model, physicians working in peripheral centers without facilities for estimating serum tumour markers can arrive at the possible diagnosis and plan appropriate management strategies
Influence of Various Sources and Levels of Fertilizer Applied through Fertigation on Hybrid Watermelon Grown in Rabi-Summer
A field experiment was conducted at Bangalore during 2006-2008 to study the effect of fertigation on growth and yield of rabi-summer grown watermelon. Seven treatments comprising varying rates and sources of fertilizers were applied. Application of water soluble fertilizer @ 70:70:70kg N:P2O5:K2O per hectare through fertigation gave significantly higher vine length, number of branches per plant and leaf area index. In general, fertigation treatments recorded higher values for number of fruits per plant, fruit weight and total soluble solids than conventional soilapplication of fertilizers. All the fertigation treatments recorded higher average marketable watermelon yield over conventional soil-application of fertilizers amounting to 7.22 to 26.4% increase. Among fertigation treatments, though recommended dose of fertilizer applied as water soluble fertilizer resulted in highest marketable-fruit yield, highest net income (Rs. 229775) and B:C ratio (3.03) was obtained in treatment with 70% of recommended dose of NPK using conventional fertilizers supplied through fertigation
Effect of Microsprinkler Fertigation on Growth and Yield of Rabi Onion
A field experiment was conducted during rabi 2005-2006 at Indian Institute of Horticultural Research, Bangalore, to study the performance of onion cv. Arka Niketan as influenced by microsprinkler fertigation using different sources and levels of fertilizers. Results indicated that crop growth in terms of leaf production, plant height, radial and equatorial diameter was not significantly influenced by the treatments. Fertigation treatments were superior for marketable bulb yield as compared to soil application of fertilizer. Also bulb yield through soil application of fertilizer increased by changing over from surface-irrigation to microsprinkler irrigation. However, bulb yield did not significantly decrease by applying just 75% of the recommended NPK fertilizers, using common or water soluble fertilizers supplied through fertigation. For achieving maximum yield, however, it is recommended to apply 100% recommended dose of fertilizers through sprinkler fertigation using water soluble fertilizers
Quantification of yield gaps in rain-fed rice, wheat, cotton and mustard in India
Rainfed farming / Crop yield / Simulation / Rice / Wheat / Cotton / Mustard / India
NETWORK ATTACK DETECTION USING MACHINE LEARNING APPROACH
With the massive growth of computer networks and the enormous increase in the number of applications that rely on it, network security is becoming very important. Moreover, almost all computer systems in any organization suffer from security vulnerabilities which are both technically difficult and economically expensive to be solved by the manufacturers. Network intrusion Detection System is one of the fundamental components to monitor and analyze the traffic to find out any possible attacks in the network. They are the safety measurements of any network. NIDS plays an important role in privacy security. But the problem is that at what level these NIDS will efficiently able to work? In this paper, the framework for the network intrusion using anomaly method by considering machine learning algorithm is proposed. And the comparison result of using different classifier is achieved
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Higher order asymptotics for large deviations – Part I
The file archived on this institutional repository is a preprint available online at https://arxiv.org/abs/1811.06793. It has not been certified by peer review. Please consult the version of record available published by IOS Press at https://doi.org/10.3233/ASY-201602 .For sequences of non-lattice weakly dependent random variables, we obtain asymptotic expansions for Large Deviation Principles. These expansions, commonly referred to as strong large deviation results, are in the spirit of Edgeworth Expansions for the Central Limit Theorem. We show that the results are applicable to Diophantine iid sequences, finite state Markov chains, strongly ergodic Markov chains and Birkhoff sums of smooth expanding maps & subshifts of finite type.P. Hebbar was partially supported by the ARO grant W911NF1710419
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