An Improved Flexibility Formulation for Nonlinear Analysis of Reinforced Concrete Frames

In this paper the finite element flexibility-based formulation for a reinforced concrete frame element is discussed. The formulation takes account of material non-linearity on the basis of the onedimensional stress-strain relationships akin to the traditional fibre element. However, the fibres in this method are replaced by transverse integration points to improve the efficiency of the method. The compatibility of strain in each section is satisfied by adopting the Navier-Bernoulli hypothesis and effect of shear tractions on the nonlinear response of the material is neglected. Two different iterative solution strategies based on secant and tangent stiffness, consistent with the flexibility formulation are employed for solving the governing equation. The accuracy of assumptions and performance of the solution schemes are studied by a numerical example

Consistent Mass and Exact Displacement Shape Function for a Tapered Curved Frame Element

The principle of virtual force is employed to derive the exact shape function for a taperedcurved frame element in space and these shape functions ca n be employed to calculate the exact consistent mass and geometric stiffness matrixes for curved-tapered frame elements. The lack of any displacement shape function with exact fulfilment of equilibrium equations by an accurate force interpolation is the salient feature of this approach. The formulation adopts the linear elastic behaviour of the material and the strain compatibility is satisfied based on the Nevier-Bernoulli hypothesis. Shear deformations are considered and the Saint-Venat hypothesis for torsion is adopted. The efficiency and accuracy of the formulation are verified using some numerical examples

Evaluation of Various Flow Control Methods in Reducing Drag and Aerodynamic Heating on the Nose of Hypersonic Flying Objects

Effective deduction of air heating load and drag is a critical issue in hypersonic vehicle engineering applications. In this research, seven various geometrical models have been proposed to study and compare the effect of each configuration on the flow field, drag, and aerodynamic heating deduction under the same flow conditions. The presented configurations in this study: (a) blunt-body geometry as a reference of comparison, (b) blunt-body geometry with a spike, (c) blunt-body geometry with an counter flow jet, (d) blunt-body geometry with a spike and counter flow jet, (e) blunt-body geometry with a spike and aerodisk, (f) blunt-body geometry with a spike, aerodisk, and root counter flow jet, (g) blunt-body geometry with a spike, four aerodisks and root counter flow jet. The Reynolds-Averaged equations have been solved using the Finite Volume Method (FVM) along with the shear stress turbulence model (k-ω SST). The flow is assumed compressible, steady-state, and axisymmetric with a free stream Mach number of 6. According to the study of each configuration’s performance related to the parameters of drag, maximum pressure, and maximum heat flux factors on the blunt-body walls, (g) configuration with a drag factor of 0.2699, maximum pressure factor of 209.8, and maximum heat flux factor of 25.1, has the most deduction on the blunt-body walls among the seven configurations. The deduction percentage of drag, maximum pressure, and maximum heat flux factors of (g) configuration to (a) configuration are %72.1, %94.5, and %79.9, respectively, which significantly diminished drag and heat flux. Also, the best configuration scenarios for drag and aerodynamic heating deduction are geometrical models of g, f, d, e, c, b, and a, respectively

Experimental Investigations & Effects of Cutting Variables on MRR and Tool Wear for AISI S2 Tool Steel

AbstractMachining is the most important of the manufacturing processes which involves the process of removing material from a work piece in the form of chips. Machining is necessary where tight tolerances on dimensions and finishes are required. Generally a machining process involves a large number of variables that affect its performance. Some of them are cutting parameters, geometry of cutting tool, coolant conditions, properties of tool material, properties of work piece, machine capabilities, etc. Among them, cutting parameters have profound effect on all kinds of performances when the same tool material and the same work piece material are used for machining. Therefore cutting parameters of speed, feed and depth of cut are considered as the process control variables and two important performance measures of CNC turning, namely, Metal Removal Rate (MRR) and Tool wear (TW) are considered for investigation. This paper presents the experimental investigations on the effects of cutting variables like Spindle speed, Feed and Depth of cut on the Material removal rate and tool wear. The experiments were conducted on AISI S2 tool steel grade on a CNC turning machine using carbide insert. The experiments were conducted as per the design of experiments. Initial trial experiments were conducted to fix the ranges for the control parameters. After conducting the experiments the MRR and Tool wear were measured and recorded. The effects were studied after plotting the graphs between the Input process parameters versus the responses using Design expert software. The results obtained in this study can by further used for optimizing the process parameters there by the optimized results help the operator to enhance the quality as well as machining rate

Control Of Active And Reactive Power Using Distributed Energy System For Power Generation In Distribution Network

At present decentralized energy sources are more beneficial than conventional centralized energy sources, distributed energy sources are decentralized energy sources. Decentralized energy sources use renewable energy sources such as small wind power, solar power, biomass, etc. In this work wind energy is used as the distributed energy source in the distribution network. Active power is generated from distributed energy source but it is unregulated as it depends on wind. D-STATCOM inverter regulates both real and reactive power with delta and modulation index controllers respectively. The proposed Fuzzy logic controller (FLC) is used in the modulation index and delta controllers to mitigate the transient period by reducing the settling time which is caused due to energy storing elements. Simulation is done using MATLAB and results are compared between without and with FLC

A rare case of mixed germ cell tumor in a teenage girl: a case report

Germ cell tumors represent only 20% to 25% of all benign and malignant ovarian neoplasms. Mixed germ cell tumors are a rare variety of non–dysgerminomatous germ cell tumors. They contain two or more elements; the most frequent combination being a dysgerminoma and an EST (Endodermal Sinus Tumor). We present a case of malignant mixed germ cell tumor comprising of yolk sac tumor, embryonal carcinoma and choriocarcinoma. A 13-year-old girl presented with a huge 25 x 18 cm mass in abdomen with raised values of CA-125, hCG, AFP (alpha-feto protein) and LDH (lactate dehydrogenase). She underwent laparotomy followed by unilateral salpingoopherectomy and infracolic omentectomy. Histopathology report revealed malignant mixed germ cell tumor comprising predominantly of EST with elements of embryonal carcinoma and non-gestational choriocarcinoma. Following surgery, she was started on adjuvant chemotherapy (Bleomycin, Etoposide and Cisplatin regimen). Mixed germ cell tumor (YST/EST, non-gestational choriocarcinoma and embryonal carcinoma) is a very rare tumor. Careful initial surgery with adequate staging biopsies followed by combination chemotherapy can greatly improve the prognosis of these patient

NORM Technique based PAPR Reduction in MC-CDMA Systems

Multicarrier code division multiple access (MC-CDMA) is one of the promising technologies for future-generation wireless networks. It offers high data rates, protection against frequency-selective fading and efficient utilization of the spectrum. The peak to average power ratio (PAPR) is very high in MCCDMA systems. The partial transmit sequence technique (PTS) and the selective mapping technique (SLM) reduce the PAPR with more computational complexity. In this study, the NORM technique was used for PAPR reduction in MC-CDMA systems. The performance of NORM was analyzed with PTS and SLM in terms of cumulative complementary distribution, power saving gain, amplifier efficiency, computational complexity and bit error rate. Simulation results showed that NORM has better PAPR reduction with less computational complexity

Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum

We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the Paleocene-Eocene Thermal Maximum (PETM) in a borehole at Ancora, New Jersey. Aside from previously-described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4 μm long and hexaoctahedral prisms up to 1.4 μm long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailability – a product of dramatic changes in weathering and sedimentation patterns driven by severe global warming – drove diversification of magnetite-forming organisms, likely including eukaryotes

Recognition of effective variables on physical safety in elementary school

One of the most important steps in planning the design of educational facilities, is attention to the physical safety of these spaces, especially in elementary schools. For this reason, the priority in the designing  is safety of the child and then due to the flexibility of the environment and tools, to give the child's chance of imagination. This study aimed to evaluate the importance of physical security and safety, environmental variables that creates safety in the educational spaces, in order to achieve a more favorable atmosphere has been done. In case study examples, solutions can be found to solve the problem in schools and in planning for the future, measures to promote safety in our schools. The research study, so that in the first phase, the theoretical research gathered through library studies, that was based on the results of the research. In the next step is to test hypotheses, field studies and interviews have been done on 8 elementary schools in Rasht, and the questionnaires were distributed in two stages, the required results gathered and analyzed. The findings showed that for respondents so many factors such as correct location of schools, access, privacy and security in the performance of schools and educational facilities described have special significance, despite the fact that is, the level of security in schools body was moderate, however, physical security, enhancing the utility of educational facilities and increase children's learning outcomes will follow