174 research outputs found

    Suitability of Indian Hot-Rolled Parallel Flange Sections for Use in Seismic Steel Moment Resisting Frames

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    Use of parallel flange I beam sections is advantageous than tapered flange I beam sections due to, increased lateral stiffness, sections do not have sloping flanges and excessive material in web and easy to weld and bolt. Nowadays the hot rolled parallel flange, narrow parallel flange beams (NPB) and wide parallel flange beams (WPB) sections as per Indian standards, having yield stress, 300 MPa, 350 MPa and 410 MPa are being manufactured. Available range of these sections can be used for steel moment resisting frames (SMRF’s) and prequalified connections as per AISC codes. When the cross section of a steel shape is subjected to large compressive stresses, the thin plates that make up the cross section may buckle before the full strength of the member is attained if the thin plates are too slender. This failure mode may be prevented by selecting suitable width-to-thickness ratios of component plates. In the present exercise, a suitability of NPB and WPB section for use in SMRF’s as per width-to-thickness limitations of AISC 341-2010 and AISC 341-2005 codal provisions is studied

    Modern Strengthening Strategies for Steel Moment Resisting Frames: State – of – the – Art –Review

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    The Northridge (1994) and Kobe (1995) earthquakes caused widespread brittle fracture in the connections of steel moment-resisting frames. As a response to this unexpected damage, a variety of new designs have been proposed. Among many connections investigated recently, two categories of connections are mostly used to enhance ductility under severe earthquake loads. One of the two categories is the reinforced connections, in which the cover plate or haunch are used to strengthen the connections. The other category is the reduced beam section (RBS) connections. In present paper recent studies of strengthening strategies or reinforced connections are discussed. In this design philosophy, the portion of the beam adjacent to the column, where the maximum moment occurs during seismic loading, is strengthened. This will force the plastic hinge to form away from the joint. The strengthening may be done using: haunches cover plates, rib plates, side plates…etc. Keywords: Strengthening schemes, reinforced connections, cover plates, rib plates, side plates, haunche

    MMC: Multiple Metric Cost Routing Metric for Wireless Mesh Networks

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    Wireless Mesh Networks (WMNs) are bringing revolutionary changes in the field of wireless communication. Routing metric is the most important factor to find the optimized route. Researchers have shown that integrating multiple performance metrics into a routing protocol is effective for attaining optimal performance because a single metric will not be able to satisfy the comprehensive requirements of WMNs. In this paper, we propose a new routing metric for WMNs, Multiple Metric Cost (MMC), integrating three metrics: 1) Available bandwidth, 2) Residual energy and 3) Expected Transmission Count (ETX).MMC results in a better throughput. We evaluated the performance of MMC for proactive, reactive and opportunistic routing protocols using the OMNET++ network simulator. Our evaluation shows that MMC performs well in all three classes of routing protocols.

    LOW COST CARBON CATHODE FOR NATURAL DYE SENSITIZED SOLAR CELL

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    Objective: Platinum film on fluorine doped tin oxide (FTO) glass surface has been used commonly in the research of dye sensitized solar cells (DSSCs). However, cost of platinum is too high to fabricate a cost effective ecofriendly DSSC. The current study has been done to replace the high cost platinum counter electrode by low cost carbon electrode. Material and Method: TiO2 nanoparticles has been synthesized and used to synthesize Photo anode of DSSC on fluorine doped tin oxide (FTO) glass surface. Platinum and Carbon cathodes has been synthesized on fluorine doped tin oxide (FTO) glass surface fabricated and their photovoltaic properties have been compared. Area of the cathode and anode has been maintained 1square centimeter. Results: Study of DSSCs reveals, carbon cathode can successfully replace the platinum cathode as efficiencies of DSSCs have been found to be more using carbon cathode as compare to the platinum cathode. Ecofriendly Eosin Y dye sensitized TiO2 nanoparticles photo anode has been used for the fabrication of DSSC. Conclusions: Investigation leads to the conclusion that carbon cathode can replace the platinum cathode in dye sensitized solar cell

    In Silico Prediction of Evolutionarily Conserved GC-Rich Elements Associated with Antigenic Proteins of Plasmodium falciparum

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    The Plasmodium falciparum genome being AT-rich, the presence of GC-rich regions suggests functional significance. Evolution imposes selection pressure to retain functionally important coding and regulatory elements. Hence searching for evolutionarily conserved GC-rich, intergenic regions in an AT-rich genome will help in discovering new coding regions and regulatory elements. We have used elevated GC content in intergenic regions coupled with sequence conservation against P. reichenowi, which is evolutionarily closely related to P. falciparum to identify potential sequences of functional importance. Interestingly, ~30% of the GC-rich, conserved sequences were associated with antigenic proteins encoded by var and rifin genes. The majority of sequences identified in the 5′ UTR of var genes are represented by short expressed sequence tags (ESTs) in cDNA libraries signifying that they are transcribed in the parasite. Additionally, 19 sequences were located in the 3′ UTR of rifins and 4 also have overlapping ESTs. Further analysis showed that several sequences associated with var genes have the capacity to encode small peptides. A previous report has shown that upstream peptides can regulate the expression of var genes hence we propose that these conserved GC-rich sequences may play roles in regulation of gene expression

    Behavior of Reduced Beam Section Moment Connection with Varying Thickness of Continuity Plate

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    Reduced beam section (RBS) connection is investigated and is widely used in US, Japan and Europe. However, very limited study is conducted with respect to Indian profiles. This study is conducted to give advantageous factors related to RBS connections with continuity plate (CP) and to learn usefulness of those connections for Indian sections. Analytical work of reduced beam section moment connections by providing continuity plates of varying thickness under monotonic drift is presented in this paper. The model is created with finite element method (FEM) and analyzed by ANSYS workbench 16.0 software. Observations were noted for the connections with varying thickness of continuity plates and without continuity plates respectively. Similarity of the results is observed between the, the connections with CP having same thickness of beam flange and with CP having half the thickness of beam flang

    Halo mass function in scale invariant models

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    Sheth-Tormen mass function has been widely used to quantify the abundance of dark matter halos. It is a significant improvement over the Press-Schechter mass function as it uses ellipsoidal collapse in place of spherical collapse. Both of these mass functions can be written in a form that is universal, i.e., independent of cosmology and power spectrum when scaled in suitable variables. However, cosmological simulations have shown that this universality is approximate. In this paper, we investigate the power spectrum dependence of halo mass function through a suite of dark-matter-only N-body simulations of seven power-law models in an Einstein-de Sitter cosmology. This choice of cosmology and a power-law power spectrum ensures the self-similar evolution of dark matter distribution, allowing us to isolate the power spectrum dependence of mass function. We find that the mass function shows a clear non-universality. We present fits for the parameters of the Sheth-Tormen mass function for a range of power-law power-spectrum indices. We find a mild evolution in the overall shape of the mass function with the epoch. Finally, we extend our result to LCDM cosmology. We show that the Sheth-Tormen mass function with parameter values derived from a matched power-law EdS cosmology provides a better fit to the LCDM mass function than the standard Sheth-Tormen mass function. Our results indicate that an improved analytical theory is required to provide better fits to the mass function.Comment: 11 pages, 10 figures. This is a much expanded and upgraded version of 0908.2702. Submitted to MNRA

    A retrospective study on maternal and perinatal outcome in pregnancy requiring DJ stent and PCN during pregnancy

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    Background: Gestational hydronephrosis (GH) is result of dilatation effect of the progesterone and mechanical compression of the gravid uterus. Management during pregnancy is challenging as routine radiological investigations and surgical treatments cannot be applied due to the potential harm to the fetus. Intervention is indicated in women who fail to respond to conservative management. Acute hydronephrosis and renal colic are common etiologies for loin pain, and can lead to severe form of urinary tract infection affecting perinatal outcome. Ureteric stenting and percutaneous nephrostomy (PCN) during pregnancy are safe, requiring no intra-operative imaging, and inserted under local anaesthesia. It provides good symptom relief, low complication rate, efficient and safe modality for women with refractory symptoms.Methods: A retrospective study of pregnant women admitted under obstetric units with acute hydronephrosis requiring DJ stenting and/or PCN. Aim was to evaluate the course and pregnancy outcomes in a tertiary center of Southern India over a period of five years.Results: Descriptive statistical analysis was done in 12 women with acute hydronephrosis in pregnancy. 66.7% were nulliparous and mean gestational age at admission was 31 weeks. Diagnosis was done by USG. One-fourth had pyelonephritis and calculus being the main pathology (n=9;75%).Women requiring DJ stent and PCN were 41.6% and 58.4% respectively. 41.7% had preterm labour. 66.7% delivered vaginally, birth weight was more than 2.5kg in 50%.Conclusions: Maternal and neonatal outcome mainly depends on the early diagnosis. In this study we emphasize on the importance of multidisciplinary team approach in the management of women with acute hydronephrosis. DJ stent and PCN are efficient and safe modalities in women with refractory symptoms

    COX-2 and PPARγ expression are potential markers of recurrence risk in mammary duct carcinoma in-situ

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    <p>Abstract</p> <p>Background</p> <p>In women with duct carcinoma in-situ (DCIS) receiving breast conservation therapy (BCT), in-breast recurrences are seen in approximately 10%, but cannot be accurately predicted using clinical and histological criteria. We performed a case-control study to identify protein markers of local recurrence risk in DCIS.</p> <p>Methods</p> <p>Women treated for DCIS with BCT, who later developed in-breast recurrence (cases) were matched by age and year of treatment to women who remained free of recurrence (controls).</p> <p>Results</p> <p>A total of 69 women were included in the study, 31 cases and 38 controls. Immunohistochemical evaluation of DCIS tissue arrays was performed for estrogen receptor, progesterone receptor, HER-2/neu, cyclin D1, p53, p21, cycloxygenase-2 (COX-2) and peroxisome proliferator activated receptor γ (PPARγ). Two markers were significantly different between cases and controls on univariate analysis: strong COX-2 expression was associated with increased risk of recurrence, with 67% vs. 24% positivity in cases and controls p = 0.006; and nuclear expression of PPARγ was associated with protection from recurrence with 4% vs. 27% positivity in cases and controls, p = 0.024. In a multivariate model which included size, grade, COX-2 and PPARγ positivity, we found COX-2 positivity to be a strong independent risk factor for recurrence (OR 7.90, 95% CI 1.72–36.23)., whereas size and grade were of borderline significance. PPARγ expression continued to demonstrate a protective trend, (OR 0.14, 95% CI 0.06–1.84).</p> <p>Conclusion</p> <p>Our findings suggest that COX-2 and PPARγ should be investigated further as biologic markers to predict DCIS recurrence, particularly since they are also potential therapeutic targets.</p
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