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The present work aims at developing a methodology for designing a swash-plate axial-piston pump whose barrel kidneys are wider than the bridges separating the kidney ports on the plate. Besides reducing pressure ripples and avoiding cavitation for minimizing the fluid-borne noise, maximization of the pump discharge has also been considered in formulating an objective function to be minimized. A comprehensive mathematical model considering oil compressibility and inertia has been developed and implemented in MATLAB/Simulink for dynamic simulation of the pump flow. The model has been found acceptable by observing a good match between its predictions of mean discharge and delivery pressure and available experimental results. A detailed parametric study has been performed and the optimum angles for the valve-plate pre-compression and the barrel kidneys have been obtained.

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Naticid taxonomy is in a state of flux owing to non-descript shell morphology and frequent convergence. Inadequate preservation of naticid body fossils has further complicated the matter in determining the true affinity and the exact time of origin of the clade. As a result, a plethora of classificatory schemes of naticid phylogeny and times of origin has been proposed. In many previous studies, true naticid affinities of fossils have been sought based on single or a few morphological characters, which are susceptible to poor preservation. In the present paper, we have attempted a holistic reappraisal of naticid taxonomy based on an extensive database of shell morphological characters and identified many distinct family- and subfamily-specific characters that survived fossilization. This approach has enabled us to identify three new naticid species from the Late Jurassic horizons of Kutch, India, thus extending back the time of origin of the family Naticidae by 30 Ma.Analysis of character matrix data reveals that the present species—Gyrodes mahalanobisi new species, Euspira jhuraensis new species, and Euspira lakhaparensis new species—belong to two subfamilies, Gyrodinae and Polinicinae. The occurrence of typical naticid drill holes on various coeval gastropod and bivalve taxa along with these body fossils provides strong supporting evidence for the naticid affinity of these forms.UUID http://zoobank.org/94188d64-075b-4bd0-8303-1ce9a0d86eb0

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