Effects of residual charge on the performance of electro-adhesive grippers

Electro-adhesion is the new technology for constructing gripping solutions that can be used for automation of pick and place of a variety of materials. Since the technology works on the principle of parallel plate capacitors, there is an inherent ability to store charge when high voltage is applied. This causes an increased release time of the substrate when the voltage is switched off. This paper addresses the issue of residual charge and suggests ways to overcome the same, so that the performance of the gripper can be improved in a cycle of pick and release. Also a new universal equation has been devised, that can be used to calculate the performance of any gripping solution. This equation has been used to define a desired outcome (K) that has been evaluated for different configurations of the suggested electro-adhesive gripper

Experimental study of a flexible and environmentally stable electroadhesive device

Electroadhesion is a promising adhesion mechanism for robotics and material handling applications due to several distinctive advantages it has over existing technologies. These advantages include enhanced adaptability, gentle/flexible handling, reduced complexity, and ultralow energy consumption. Unstable electroadhesive forces, however, can arise in ambient environments. Electroadhesive devices that can produce stable forces in changing environments are thus desirable. In this study, a flexible and environmentally stable electroadhesive device was designed and manufactured by conformally coating a layer of barium titanate dielectric on a chemically etched thin copper laminate. The results, obtained from an advanced electroadhesive “normal force” testing platform, show that only a relative difference of 5.94% in the normal force direction was observed. This was achieved when the relative humidity changed from 25% to 53%, temperature from 13.7 �C to 32.8 �C, and atmospheric pressure from 999 hPa to 1016.9 hPa. This environmentally stable electroadhesive device may promote the application of the electroadhesion technology

PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec

Metamorphism of the Mullerneset Formation, St. Jonsfjorden, Svalbard

The metamorphism of upper greenschist facies metasediments exposed in the extreme southwestern portion of St. Jonsjorden, Svalbard, is described. The rocks form part of the Miillerneset Formation of the late Precambrian age Kongsvegen Group and constitute a portion of the central-western Spitsbergen Caledonides. Four deformations (DI-D~) and two metamorphic episodes (MI and Mz) have affected the rocks of the Miillerneset area. MI was a prograde event which was initiated prior to the onset of the D1 and continued through this deformation. Pre-DI metamorphism reached biotite grade whereas garnet grade was attained syn-DI. MZ was a lower-middle greenschist facies metamorphism associated with Dz. The results of quantitative geothermometry in the pelitic rocks show that peak MI metamorphic temperatures decrease southwards across the field area from about 540&deg;C to 510&deg;C. Geobarometry and estimates of depth of burial indicate that MI pressures were in the range of 5-7kb. The data are consistent with geothermal gradients in the range of 21 f 4"C/km to 24 f S"C/km. MZ metamorphic conditions are not precisely determinable but temperatures and pressures were probably less than those attained during MI. It is suggested that the rocks of central-western Spitsbergen were originally deposited in an aulacogen before the initiation of Caledonian diastrophism