Friction in ultra-thin conjunction of valve seals of pressurised metered dose inhalers

In many drug dispensing devices, such as syringes and inhalers, a rubber disk is used as a seal. During device actuation the seal is subjected to friction which in turn causes its deformation. This can lead to suboptimal performance of the device and consequent variability in delivered dose. Seal friction is complex, arising from adhesion of rubber in contact with the moving interface, viscous action of a thin film of fluid and deformation of seal asperities. Therefore, the first step in understanding the conjunctional behaviour of rubber seals is the fundamental study of mechanisms of friction generation. A developed model can then be validated against measurements. The validated model can then be used to predict product performance, robustness and variability due to manufacturing tolerances. A friction model, based on the aforementioned mechanisms, for prediction of seal friction has been developed and validated against measured friction tests performed on both nano and component level scales. Pressure changes in the metering chamber have been taken into account in the model. Friction data are presented for nitrile rubber, using a silicon nitride AFM tip for nano-scale interactions and polybutylene terephthalate (PBT) for asperity interactions at a component level, where a traditional friction test apparatus is utilised. Reasonable agreement is found between measurements and model predictions for the nano-scale coefficient of friction of rubber against silicon nitride. Similarly, good agreement has been obtained for the mean coefficient of friction of rubber against PBT. It was found that the model was capable of predicting static friction coefficient reasonably well and the contribution to the coefficient of friction was mostly due to adhesive friction. The inputs of viscous and ploughing friction were negligible

Разработка навесной системы для управления пропашным культиватором в автоматическом режиме

Weed control automation appears to be a very promising technology based on the tremendous advances in computer processing, machine vision and robotics. Machine vision systems are based on size differences between crops and weeds and or on the regular structure of crop rows, allowing the system to recognize crop plants and control surrounding weeds. The paper provides description of the mounted system for orienting the row cultivator in rows and its displacement relative to the tractor using vision systems and automatic control. The developed technical vision system is capable of clearly identifying sugar beet leaves based on the deep learning artificial neural networks technology, and a specially developed algorithm for identifying the center of the row spacing to control the moving part of the cultivator in the required direction to level the inaccuracy of the tractor. The use of controlled mounted device with a tractor and an implement based on vision systems, the accuracy of technological operations for the row crops care, will increase the technical level of the machine and tractor unit, and reduce labor costs. Technical vision systems and automatic control of the cultivator will improve the quality of inter-row cultivation of row crops and reduce the pesticide load on the environment. The results of these studies can be used to create machines for cultivation of agricultural crops with an automated control system.Автоматизация удаления сорняков представляется очень перспективной технологией исходя из огромных усовершенствований в сфере компьютерной обработки, машинного зрения и робототехники. Системы машинного зрения базируются на разнице в цвете между культурными растениями в рядке и почвы. В статье приводится описание навесной системы для ориентации пропашного культиватора по рядкам и его смещение относительно трактора с помощью систем технического зрения и автоматического управления. Разработанная система технического зрения способна на основе использования технологии искусственных нейронных сетей глубокого обучения чётко определять листья сахарной свеклы, а специально разработанный алгоритм выявления центра междурядья направлять подвижную часть культиватора в требуемую сторону для нивелирования неточности хода трактора. Применение управляемого навесного устройства с трактором и орудием на основе систем технического зрения точность выполнения технологических операций по уходу за пропашными культурами, повысит технический уровень машинотракторного агрегата, снизит трудозатраты. Использование систем технического зрения и автоматического управления культиватором позволит повысить качество междурядных обработок пропашных культур и уменьшит пестицидную нагрузку на окружающую среду. Результаты настоящих исследований могут быть использованы при создании машин для возделывания сельскохозяйственных культур с автоматизированной системой управления

Town Of Great Barrington, Massachusetts Annual Reports For The Fiscal Year 2016 July 1, 2015 to June 30, 2016

SABRE (Sodium-iodide with Active Background REjection) is a direct dark matter search experiment based on an array of radio-pure NaI(Tl) crystals surrounded by a liquid scintillator veto. Twin SABRE experiments in the Northern and Southern Hemispheres will differentiate a dark matter signal from seasonal and local effects. The experiment is currently in a Proof-of-Principle (PoP) phase, whose goal is to demonstrate that the background rate is low enough to carry out an independent search for a dark matter signal, with sufficient sensitivity to confirm or refute the DAMA result during the following full-scale experimental phase. The impact of background radiation from the detector materials and the experimental site needs to be carefully investigated, including both intrinsic and cosmogenically activated radioactivity. Based on the best knowledge of the most relevant sources of background, we have performed a detailed Monte Carlo study evaluating the expected background in the dark matter search spectral region. The simulation model described in this paper guides the design of the full-scale experiment and will be fundamental for the interpretation of the measured background and hence for the extraction of a possible dark matter signal

Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM) readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 x 15 x 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The new prototype uses a larger SiPM array to cover the entire top face of the tile. This paper details the comparative performance of the two prototype designs. A deuterium-tritium (DT) fast-neutron source was used to compare the relative light collection efficiency of the two designs. A collimated UV light source was scanned across the detector face to map the uniformity. The new prototype was found to have 9.5 times better light collection efficiency over the original design. Both prototypes exhibit spatial non-uniformity in their response. Methods of correcting this non-uniformity are discussed