Influence of Fluid Compressibility and Movements of the Swash Plate Axis of Rotation on the Volumetric Efficiency of Axial Piston Pumps

This paper describes the design of a swash plate axial piston pump and the theoretical models describing the bulk modulus of aerated and non-aerated fluids. The dead space volume is defined and the influence of this volume and the fluid compressibility on the volumetric efficiency of the pump is considered. A displacement of the swash plate rotation axis is proposed to reduce the dead space volume for small swash plate swing angles. A prototype design of a pump with a displaced axis of rotation of a swash plate with two directions of delivery is presented, in which the capacity is changed by means of a valve follow-up mechanism. Comparative results for a pump with a displaced and a non-displaced swash plate rotation axis are presented, which confirm that displacement of the swash plate rotation axis causes an increase in volumetric efficiency that is apparent for high pressure discharge and small swash plate angles. The determined characteristics were compared with a mathematical model taking into account the compressibility of the fluid in the dead space volume and a satisfactory consistency was obtained.

ДОСЛІДЖЕННЯ ЕНЕРГОВИТРАТ ТАРІЛЧАСТИХ ЖИВИЛЬНИКІВ ДЛЯ СИПКИХ МАТЕРІАЛІВ

Creation of mathematical models that allow determining the relationship between the design and technological parameters of the plate feeders and the energy consumption arising during their operation. Methodology. The work uses the classical mechanics principles, the contact interaction of solids theory and the mathematical modeling method. Findings. The paper considers the design and operation principle of a continuous plate feeder, defines its main design and technological parameters. The factors that create mechanical loads on the drive of the feeder plate are investigated. Mathematical models have been developed that make it possible to determine the moments of resistance and the power consumed by an electric motor during the equipment operation. The proposed models make it possible to determine the load on the drive in static and dynamic operation modes and take into account the design, technological parameters of the equipment and the bulk material physical and mechanical properties. The study results of the friction coefficients influence, the knife position and the force of its pressing on the plate surface, the plate rotation speed on the loads acting on the electric drive are presented. It has been found that the drive calculation is expedient for the mode in which the distance between the knife edge and the rotation axis of the plate is maximum, which corresponds to the operation at maximum load. It has been determined that a change in the feeder technological parameters (plate rotation speed, knife position) can lead to a change in the load on the electric drive by 86%, which must be taken into account when choosing a drive. Originality. Mathematical models of the continuous plate feeder operation have been developed, which make it possible to determine the relationship between the design and technological parameters of the plate feeders and energy consumption. Practical value. The results obtained make it possible to determine the load on the plate drive by the known design, technological parameters and bulk material physical and mechanical properties.

A record of plume-induced plate rotation triggering seafloor spreading and subduction initiation

<p>The formation of a global network of plate boundaries surrounding a mosaic of lithospheric fragments was a key step in the emergence of Earth’s plate tectonics. So far, propositions for plate boundary formation are regional in nature but how plate boundaries are being created over 1000s of km in short periods of geological time remains elusive. Here, we show from geological observations that a >12,000 km long plate boundary formed between the Indian and African plates around 105 Ma with subduction segments from the eastern Mediterranean region to a newly established India-Africa rotation pole in the west-Indian ocean where it transitioned into a ridge between India and Madagascar. We find no plate tectonics-related potential triggers of this plate rotation and identify coeval mantle plume rise below Madagascar-India as the only viable driver. For this, we provide a proof of concept by torque balance modeling revealing that the Indian and African cratonic keels were important in determining plate rotation and subduction initiation in response to the spreading plume head. Our results show that plumes may provide a non-plate-tectonic mechanism for large plate rotation initiating divergent and convergent plate boundaries far away from the plume head that may even be an underlying cause of the emergence of modern plate tectonics.</p>

Insight into the dynamics of magneto-casson hybrid nanoliquid caused by a plate rotation

Purpose This paper aims to present the analytical investigation on an unsteady magneto-convective rotation of an electrically conducting non-Newtonian Casson hybrid nanoliquid past a vertical porous plate. The effects of thermal radiation, heat source/sink and hydrodynamic slip phenomenon are also taken into account. Ethylene glycol (EG) is adopted as a base Casson fluid. The Casson fluid model is accounted for to describe the rheological characteristics of non-Newtonian fluid. EG with copper and alumina nanoparticles is envisaged as a non-Newtonian Casson hybrid nanoliquid. The copper-alumina-ethylene glycol hybrid nanoliquid is considered as the regenerative coolant. Design/methodology/approach The perturbation method is implemented to develop the analytical solution of the modeled equations. Acquired solutions are used to calculate the shear stresses and the rate of heat transfer in terms of amplitudes and phase angles. Numerical results are figured out and tabled to inspect the physical insights of various emerging parameters on the pertinent flow characteristics. Findings This exploration discloses that the velocity profiles are strongly diminished by the slip parameter. Centrifugal and Coriolis forces caused by the plate rotation are found to significantly change the entire flow regime. The supplementation of nanoparticles is to lessen the amplitude of the heat transfer rate. A comparative study is carried out to understand the improvement of heat transfer characteristics of Casson hybrid nanoliquid and Casson nanoliquid. However, the Casson hybrid nanoliquid exhibits a lower rate of heat transfer than the usual Casson nanoliquid. Practical implications This proposed model would be pertinent in oceanography, meteorology, atmospheric science, power engineering, power and propulsion generation, solar energy transformation, thermoelectric and sensing material processing, tumbler in polymer manufacturing, etc. Motivated by such practical implications, the proposed study has been unfolded. Originality/value The novelty of this paper is to examine the simultaneous effects of the magnetic field, Coriolis force, suction/injection, slip condition and thermal radiation on non-Newtonian Casson hybrid nanoliquid flow past an oscillating vertical plate subject to periodically heating in a rotating frame of reference. A numerical comparison is also made with the existing published results under some limiting cases and it is found that the results are in good agreement with them. An in-depth review of the literature and the author’s best understanding find that such aspects of the problem have so far remained unexplored.

Taking time to twist a continent—Multistage origin of the New Zealand orocline

In New Zealand, a giant coherent “Z” shape is defined by several curvilinear pre-Cenozoic basement terranes that extend across Zealandia for >1500 km along strike. It is widely assumed that this curvature was the result of bending during the Neogene, which together with ∼450 km of dextral displacement on the Alpine fault accommodated a total of ∼750 km of dextral shear through the New Zealand plate boundary zone between the Australian and Pacific plates. This would make it a very simple form of orocline. In fact, we show that its development was surprisingly complex and protracted, with a composite origin. Its western and southern parts were bent as much as 70° in the Mesozoic. In the Late Cretaceous, the already bent terranes were offset sinistrally by ∼250 km along the cross-cutting proto–Alpine fault, which acted as a transform to the rift between East and West Antarctica. Since the Eocene, and after Zealandia had completely separated from Antarctica, the two sides of the Alpine fault have undergone 45° of relative plate rotation, further bending the terranes. However, the eastern part of what appears today to be the same oroclinal structure has been created entirely since the Eocene, and mainly during the Neogene phase of dextral shear through the plate boundary, with large-scale internal bending and shortening. We suggest that multistage and composite evolutions may be typical features of oroclines, which would be difficult to unravel without a rich tectonic and plate motion database, such as that available for the New Zealand region.

Detecção e avaliação de efeitos geodinâmicos em uma porção das estações GNSS brasileiras

Neste trabalho apresentamos uma metodologia para detecção de possíveis efeitos geodinâmicos, utilizando dados GNSS, modelos de velocidade SIRGAS, Geológico e Geofísico. As observações GNSS foram processadas para obtenção da variação da coordenada vertical e horizontal. Os modelos de velocidade VEMOS2009 e 2015 serviram como base comparativa para verificar os resultados obtidos com o processamento GNSS. A partir do conjunto de vetores de velocidades das estações da Rede Brasileira de Monitoramento Contínuo (RBMC) obtidos do NNR-NUVEL-1A, estimaram-se os elementos definidores do movimento da placa SOAM. Em seguida, foram realizadas algumas análises e comparações com os vetores de rotação da placa SOAM obtidas pelo modelo APKIM2008. As análises conduzidas tiveram por base observações contínuas, desde 2007 até 2016, junto a uma porção de estações GNSS pertencentes à RBMC (estações SIRGAS-CON). Os resultados considerando os modelos de velocidade de SIRGAS mostraram que após o terremoto no Chile em algumas regiões do Brasil houveram efeitos geodinâmico. Em comparação aos modelos geológico e geofísico observou-se que o campo de velocidade definido no processamento GNSS conseguiu retratar a realidade, como caso de estudo foi considerado a estação de Imbituba. Detection and assessment of geodynamic effects on a portion of Brazilian GNSS stations A B S T R A C TThis work presents a methodology for detecting possible geodynamic effects using GNSS data, SIRGAS, Geological, and Geophysical velocity models. GNSS observations were processed to obtain the variation for the vertical (up) and horizontal coordinates. The VEMOS2009 and 2015 velocity models served as a comparative basis to verify the results obtained with GNSS processing. From the set of velocity vectors of stations belonging to the Brazilian Network for Continuous Monitoring of the GNSS (RBMC) obtained from NNR-NUVEL-1A, estimated the defining elements of the movement of the SOAM plate. Then, it performed some analyses and comparisons with the SOAM plate rotation vectors obtained by the APKIM2008 model. The studies conducted were based on continuous observations, from 2007 to 2016, on a portion of GNSS stations belonging to RBMC (SIRGAS-CON stations). The results considering the SIRGAS velocity models showed that after the earthquake in Chile, in some regions of Brazil, there were geodynamic effects. Comparison to the geological and geophysical models, it was observed that the velocity field defined in GNSS processing was able to portray reality, as well as case study, which was considered the Imbituba station.Keywords: geodynamic, geophysics, geologic, lithospheric plate.

Separation of tectonic and local components of horizontal GPS station velocities: a case study for glacial isostatic adjustment in East Antarctica

SUMMARY Accurate measurement of the local component of geodetic motion at GPS stations presents a challenge due to the need to separate this signal from the tectonic plate rotation. A pressing example is the observation of glacial isostatic adjustment (GIA) which constrains the Earth’s response to ice unloading, and hence, contributions of ice-covered regions such as Antarctica to global sea level rise following ice mass loss. While both vertical and horizontal motions are of interest in general, we focus on horizontal GPS velocities which typically contain a large component of plate rotation and a smaller local component primarily relating to GIA. Incomplete separation of these components introduces significant bias into estimates of GIA motion vectors. We present the results of a series of tests based on the motions of GPS stations from East Antarctica: (1) signal separation for sets of synthetic data that replicate the geometric character of non-separable, and separable, GIA-like horizontal velocities; and (2) signal separation for real GPS station data with an appraisal of uncertainties. For both synthetic and real motions, we compare results where the stations are unweighted, and where each station is areal-weighted using a metric representing the inverse of the spatial density of neighbouring stations. From the synthetic tests, we show that a GIA-like signal is recoverable from the plate rotation signal providing it has geometric variability across East Antarctica. We also show that areal-weighting has a very significant effect on the ability to recover a GIA-like signal with geometric variability, and hence on separating the plate rotation and local components. For the real data, assuming a rigid Antarctic plate, fitted plate rotation parameters compare well with other studies in the literature. We find that 25 out of 36 GPS stations examined in East Antarctica have non-zero local horizontal velocities, at the 2σ level, after signal separation. We make the code for weighted signal separation available to assist in the consistent appraisal of separated signals, and the comparison of likely uncertainty bounds, for future studies.

Topological optimization of variable area plate capacitors for coupled electromechanical energy harvesters

This article examines how topological optimization can be applied to identify nonintuitive capacitor plate patterning that maximizes average power dissipated through an electrical circuit during energy harvesting. Coupled electromechanical equations of motion are derived that include both the instantaneous and change in overlapping conductive area as functions of plate rotation. A genetic algorithm is used to optimize these terms and then map them to physical plate configurations. The results obtained apply specifically to the case presented; however, the methods are general and can be used to solve a broad range of electrostatic energy harvesting problems.