An illustration of the physical robustness of silica monolithic rod columns

A commercial silica monolithic rod column (100 × 4.6 mm) was cut into smaller sections using a saw. Each time a section was cut from the column, the performance of the remaining intact monolith was retested. No significant change in the performance of the bed was recorded following the removal of 40 mm of the column in three separate cut sections. The work illustrates that monoliths are extremely robust and that they can be remodelled to different lengths if required, or a blocked section of the column (i.e. inlet) could be removed in much the same manner as for GC columns.

Combustion simulations for a self controlling variable compression ratio connecting rod

Variable compression ratio enables an engine to achieve increased efficiency at part loads, where the majority of driving occurs, without sacrificing full load power requirements or increasing the risk of engine knock. Although over 100 patents and patent applications exist none of these systems has been commercialized yet due to issues related to feasibility, cost and frictional loss. A new approach of a self controlling variable compression ratio connecting rod is presented that does not need a friction intensive external activation and that could even be retrofitted. The potential in fuel consumption and exhaust emission reduction as well as increased power and torque output for this concept has been verified in combustion simulations utilizing the latest research results related to the dynamic heat transfer in the combustion chamber from Professor Kleinschmidt from the University of Siegen, Germany. The self controlling variable compression ratio connecting rod allows the con rod to compress at high load conditions thereby increasing cylinder volume to alleviate combustion pressures and temperatures and therefore limit knock onset. The biggest efficiency gains can be achieved at medium load where the reduction of heat loss during the compression of the connecting rod plays a major role additional to the well known efficiency gains of an increased compression ratio. The combustion simulation results shows fuel consumption can be reduced by between 3% and 5% during part load and wide open throttle operation at various engine speeds. Emissions are also reduced significantly; particularly NOx and CO emissions were reduced by up to 35%.The self controlling variable compression ratio connecting rod allows the con rod to compress at high load conditions thereby increasing cylinder volume to alleviate combustion pressures and temperatures and therefore limit knock onset. The biggest efficiency gains can be achieved at medium load where the reduction of heat loss during the compression of the connecting rod plays a major role additional to the well known efficiency gains of an increased compression ratio.The combustion simulation results shows fuel consumption can be reduced by between 3% and 5% during part load and wide open throttle operation at various engine speeds. Emissions are also reduced significantly; particularly NOx and CO emissions were reduced by up to 35%.

Bearing e.g. connecting rod bearing, mounting method for reciprocating piston engine of motor vehicle, involves fixedly connecting bearing housing parts by welding process, where welding of parts is performed in defined external region

The method involves dividing a bearing housing into bearing housing parts (4A, 4B) by fracture-splitting. Bearing half-shells (5) are inserted into the parts. The parts are combined to a bearing that encloses a shaft, and are fixedly connected with each other by a welding process such as resistance welding, ultrasonic welding or cold pressure welding process. The welding of the parts is performed in a defined external region. An insulation material is applied between the half-shells and/or the shaft and the housing parts before welding. The parts are pressed on each other during welding.

Large compound vesicles from amphiphilic block copolymer/rigid-rod conjugated polymer complexes

Morphology evolution in complexes of amphiphilic block copolymers poly(styrene)-b-poly(acrylic acid) (PS-b-PAA) and poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO) in the presence of polyaniline (PANI) in aqueous solution is reported. Transmission electron microscopy, atomic force microscopy, and dynamic light scattering techniques were used to study the morphologies at various PANI contents [aniline]/[acrylic acid] ([ANI]/[AA]) ranging from 0.1 to 0.7. The interpolyelectrolyte complex formed between PAA and PANI plays a key role in the morphology transformation. Spherical micelles formed from pure block copolymers were transformed into large compound vesicles upon increasing PANI concentration due to internal block copolymer segregation. In addition to varying PANI content, the kinetic pathway of nanoparticle formation was controlled through different water addition methods and was critical in the formation of multigeometry nanoparticles.

Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO2 overlay coating on TiO2 nanoparticle working electrode

Novel TiO2 single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO2 nanorods on TiO2 nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO2 nanorods had lower dye loading than TiO2 nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO2 nanorods received less resistance than that in TiO2 nanoparticle aggregation. By just applying a thin layer of TiO2 nanorods on TiO2 nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO2 nanoparticle layer covered with 3 μm thick TiO2 nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs.

A microstructure based analytical model for tensile twinning in a rod textured Mg alloy

Abstract A model for tensile twinning during the compression of rod textured magnesium is developed based on the idea that these twins nucleate at grain boundaries and that when the twin number density per grain is low these twins readily give rise to the formation of other 'interaction' twins in adjacent grains. Experimental observations of twin aspect ratios measured at a single grain size and twin number densities measured over four grain sizes were used to determine model material parameters. Using these, the model provides reasonable predictions for the observed magnitudes and trends for the following observations:Effect of grain size and stress on twin volume fraction, fractional twin length and the fraction of twin contact.Effect of grain size on the yield stress.Effect of grain size on the general shape of the stress-strain curve at low strains. A parametric study shows the model to be quite robust but that it is particularly sensitive to the value of the exponent assumed for the twin nucleation rate law. It is seen that preventing the formation of interaction twins provides an important avenue for hardening and that the flow stress is also particularly sensitive to the relaxation of the twin back stresses. The model shows the importance of taking microstructure into account when modelling twinning.

Rod length influence in torque measurement of SPT-T test

Since Ranzini suggested supplementing the SPT test with measurement of the torque required to turn the split spoon sampler after driving, many Brazilian engineers have been using this in the design of pile foundations. This paper presents a study of the rod length influence in the torque measurement. A theoretical study of material resistance considering torsion and bending in a thin wall tubular steel shaft was performed. It makes possible to conclude that the shearing tension caused by the proper weight represents less than 1% of the shearing tension caused by the turning moment. In addition, an experimental study was done with electric torquemeters fixed in a horizontal rod system. The tests were being carried out to analyze rods of one meter to twenty meters in length and the measurements were collected at the ends of each rod length verifying the efficiency data. As a result, it is possible to verify that the torque difference through rod length is lower than minimum scales of mechanical torquemeters that are used on practical engineering. Also a fact to be considered is a big torque loss for values under 20 N.m of applied torque. This way, the SPT-T is not adequate to low consistency soil. Copyright ASCE 2007.

The fractional and nonlinear magneto-flexible rod

This paper deals with a system involving a flexible rod subjected to magnetic forces that can bend it while simultaneously subjected to external excitations produces complex and nonlinear dynamic behavior, which may present different types of solutions for its different movement-related responses. This fact motivated us to analyze such a mechanical system based on modeling and numerical simulation involving both, integer order calculus (IOC) and fractional order calculus (FOC) approaches. The time responses, pseudo phase portraits and Fourier spectra have been presented. The results obtained can be used as a source for conduct experiments in order to obtain more realistic and more accurate results about fractional-order models when compared to the integer-order models. © Published under licence by IOP Publishing Ltd.

A América Latina, de Manoel Bomfim, e Ariel, de José Enrique Rodó: ensaios de interpretação latino-americana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A nação escrita entre a prática e o ideal: os projetos de Monteiro Lobato e de José Enrique Rodó

Pós-graduação em Ciências Sociais - FFC

Ideologia e política em José Enrique Rodó: liberalismo e jacobinismo no Uruguai (1895-1917)

Pós-graduação em História - FCHS

Análise estrutural de Tie-Rod pelo método dos elementos finitos e através de cálculos analíticos

Currently one of the great concerns of the aeronautical industry is in relation to the security and integrity of the aircraft and its equipments / components when under critical flight maneuvers such as during landing / takeoff and emergency maneuvers. The engineers, technicians and scientists are constantly developing new techniques and theories to reduce the design time and testing, ir order to minimize costs. More and more the Finite Element Method is used in the structural analysis of a project as well as theories based on experimental results. This work aimed to estimate the critical load to failure for tensile, compression and buckling of the Tie-Rod, a fixture aircraft widely used on commercial aircrafts. The analysis was performed by finite element method with the assistance of software and by analytical calculations. The results showed that the Finite Element Method provides relative accuracy and convenience in the calculations, indicating critical load values slightly lower than those found analytically for tension and compression. For buckling, the Finite Element Method indicates a critical load very similar to that found analytically following empirical theories, while Euler's theory results in a slightly higher value. The highest risk is to fail by buckling, but the geometric irregularity of Tie-Rod pieces makes difficult the calculations, therefore a practical test must be done before validation of the results

Book Review of Improved Earth: Prairie Space as Modern Artefact, 1869-1944 by Rod Bantjes

In this short but suggestive study, sociologist Rod Bantjes examines how contending visions of modernity shaped the social and physical landscapes of the Canadian prairies. "[B]oth statesmen and prairie farmers were infused with the modernist spirit of innovation, the will creatively (and destructively) to transform their worlds," Bantjes argues. His provocative view of farmers as agents of modernity reflects recent scholarship that seeks to explore "multiple modernities," or the notion that ideas and practices of modernism must be regarded not as monolithic but rather as contested and multivocal, and must be examined in their historical and geographical contexts.

Tribute to Rod Gangwish and Mark Gustafson

President Williamson, honored guests and friends, it is such a pleasure to be here with you tonight, and such a privilege to deliver this tribute to our 2004 Nebraska Hall of Agricultural Achievement honorees, Rod Gangwish and Mark Gustafson.