IRONSperm swimming by rigid-body rotation versus transverse bending waves influenced by cell membrane charge

Cell membrane potential affects the electrostatic self-assembly of magnetizable nanoparticles around the flagellum of sperm cells, leading to the formation of biohybrid microrobots (i.e., IRONSperm) with various bending stiffness. Here we explain the influence of bull sperm cell membrane potential on the formation of two types of IRONSperm samples that are produced by electrostatic self-assembly. The first type is a proximal-coated soft body with nanoparticles concentrated on the head to maintain high flexibility of the flagellum and create a passively propagating transverse bending wave under the influence of an external rotating magnetic field. The second type is a rigid-body with nanoparticles approximately uniformly distributed along the length to provide arbitrary geometry that maintains a constant chiral shape and propel by rotation about its long axis. We present a magneto-elastohydrodynamic model to predict the swimming speed at low Reynolds number for rigid IRONSperm with arbitrary shapes, and show that decreasing the bending stiffness allows the model to capture the behavior of its soft counterpart. While the response of a rigid chiral IRONSperm is distinguished by a greater swimming speed with a smooth decay with frequency, the benefit of a soft flagellum in certain scenarios would present a much smaller range of frequencies for wireless actuation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic

Fleksibilni slijedni sustav s koncentriranim parametrima sa suzbijanjem vibracija korištenjem LQR-a bez senzora

This work attempts to achieve motion control along with vibration suppression of flexible systems by developing a sensorless closed loop LQR controller. Vibration suppression is used as a performance index that has to be minimized so that motion control is achieved with zero residual vibration. An estimation algorithm is combined with the regular LQR to develop sensorless motion and vibration controller that is capable of positioning multi degrees of freedom flexible system point of interest to a pre-specified target position with zero residual vibration. The validity of the proposed controller is verified experimentally by controlling a sensorless dynamical system with finite degrees of freedom through measurements taken from its actuator.U ovom radu opisan je fleksibilni slijedni sustav sa suzbijanjem vibracija upravljan LQR regulatorom u zatvorenom upravljačkom krugu bez senzora. Vibracije su korištene u težinskoj funkciji koja se minimizira s ciljem eliminiranja rezidualnih vibracija iz slijednog sustava. Kombinirajući algoritam estimacije s klasičnim LQRom, razvijen je regulator za upravljanje gibanjem i vibracijama bez korištenja senzora, koji je sposoban pozicionirati određenu točku fleksibilnog sustava s više stupnjeva slobode u predefiniranu željenu točku bez preostalih vibracija. Validacija predloženog regulatora provedena je eksperimentalno upravljajući dinamičkim sustavom s konačnim brojem stupnjeva slobode uz korištenje mjerenja s aktuatora

Measuring the Effect of Healthcare Service Quality Dimensions on Patient’s Satisfaction in The Algerian Private Sector

There is a gap in marketing literature related to impact of service quality dimensions on perceived service quality and patient satisfaction, in the private healthcare industry. The healthcare system is responsible for improving the general population’s health in a country. To differentiate from competitors, the quality of service is mainly considered a critical success factor for hospitals (Azmit et al., 2017). Therefore, competition is essential for improving quality and patient satisfaction in healthcare institutions (Kitapci et al., 2014). This article aims to determine the relationship between health service quality dimensions and patient satisfaction in the healthcare sector. Specifically, the paper seeks to find out the most critical dimensions of service quality, which is used to evaluate the characteristics of private healthcare service quality as perceived by patients. A field study was carried out on a sample of 208 patients in Tlemcen city in Algeria. The questionnaire developed for this study was based on a SERVQUAL model specifically, based on Parasuraman, Zeithaml, and Berry, (1985) variables that identified the influence of five dimensions (i.e., reliability, tangibility, assurance, responsibility, and empathy) in healthcare service environments on patient satisfaction. The results have found after the application of structural equation modelling that: reliability, tangibility, assurance, responsibility was more significant in contributing to patient satisfaction, while empathy was not significant. This indicates that patients tend to have a positive perception about the health service if they consider the perceived quality of the health service to be credible, reliable, tangible, and responsive, even though they may feel that the health provider does not empathize with them. Hence, healthcare industry practitioners can consider this model as an instrument to assess healthcare and help improve their service quality. Therefore, service provider managers can use this instrument to assess private hospital service quality in Algeria and other African countries

Yüksek hassasiyetli montaj işlemleri için minyatür delta robot tasarımı, en iyilemesi ve denetimi

Bu makalede yüksek hassasiyetli montaj uygulamaları için minyatür delta robot tasarımı, en iyilemesi ve denetimi sunulmaktadır. Bu delta robot modüler bir mikro fabrika kavramının bir parçası olup esas olarak hızlı ve hassas al-bırak işlemlerini gerçekleştirecek bir manipülatör olarak kullanılacaktır. Robotun önceden belirlenmiş 40 mm3 kübik şekilli bir çalışma uzayı için gerekli olan kinematik parametrelerin elde edilmesi için kinematik analiz gerçekleştirilmiştir. En iyileme sürecinden elde edilen parametreler kullanılarak tasarım süreci gerçekleştirilmiş ve robot üretilmiştir. Tasarlanan gerekli elektronik aksam ile ve denetim algoritmasıyla tasarım testleri gerçekleştirilmiş ve ümit verici sonuçlar elde edilmiştir. Tasarımın iyileştirilmesine yönelik yapılacak çalışmalar belirtilmiş ve yeni bir tasarım üzerinde çalışılmaya başlanmıştır