This paper presents a theoretical and experimental study on controller design for the AMBs in a small-scale flywheel energy storage system,where the main goals are to achieve low energy consumption and improved rotord...This paper presents a theoretical and experimental study on controller design for the AMBs in a small-scale flywheel energy storage system,where the main goals are to achieve low energy consumption and improved rotordynamic stability.A H-infinity optimal control synthesis procedure is defined for the permanent-magnet-biased AMB-rotor system with 4 degrees of freedom.Through the choice of design weighting functions,notch filter characteristics are incorporated within the controller to reduce AMB current components caused by rotor vibration at the synchronous frequency and higher harmonics.Experimental tests are used to validate the controller design methodology and provide comparative results on performance and efficiency.The results show that the H-infinity controller is able to achieve stable rotor levitation and reduce AMB power consumption by more than 40%(from 4.80 to 2.64 Watts)compared with the conventional PD control method.Additionally,the H-infinity controller can prevent vibrational instability of the rotor nutation mode,which is prone to occur when operating with high rotational speeds.展开更多
The current research joins previous studies in examining post-traumatic stress disorder (PTSD) and burnout among healthcare workers. The research focuses on the experiences of pediatric residents working in an emergen...The current research joins previous studies in examining post-traumatic stress disorder (PTSD) and burnout among healthcare workers. The research focuses on the experiences of pediatric residents working in an emergency department both in normal times and during the Covid pandemic. Research conducted prior to and during the Covid pandemic outbreak shows negative psychological effects among healthcare workers. Most of that research was conducted within the positivistic-quantitative paradigm. The current study is qualitative and focuses on pediatric residents who provide medical services to a unique population in a peripheral region of Israel, namely the Bedouin-Arab population. The research questions are the following: What characterizes pediatric residents’ work, in general and during the pandemic? Do they show signs of burnout and secondary trauma? How do they perceive their work with the Bedouin-Arab population, especially during the pandemic? The study, conducted within the phenomenological genre, included 14 pediatric residents in a large hospital in Israel’s periphery. Semi-structured clinical interviews were employed, in addition to questionnaires that examined PTSD and burnout to enhance the reliability of the findings. The results show that all residents reported stressful incidents in which patients’ physical integrity was threatened. The residents described the special nature of the medical cases they treated in routine times and during the pandemic outbreak, which stems mostly from the specific characteristics the population of Israel’s periphery. While at the early stages of the pandemic, the residents experienced reduced work pressure, they reported substantial difficulties later in the crisis, which intensified their sense of physical and emotional stress. Most residents reported feeling inadequately prepared for dealing with traumatic events. According to the results, most residents displayed secondary trauma (12 participants in interviews and 11 in questionnaires), which can be classified into categories based on the DSM-5. In the interviews, all 14 participants reported various signs of burnout. The questionnaires indicated burnout symptoms among 10 participants. Giving a voice to pediatric residents, the study highlights the complexity of their routine work as well as their role during the Covid crisis. Based on the findings, recommendations have been made for policymakers. The study highlights the importance of raising awareness to the implications of the residents’ rough work conditions in routine and emergency times and to the need to develop social support and intervention programs that might improve their well-being during their professional work.展开更多
The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultraco...The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultracompact combined laser-beam shaper system provides a versatile illumination module for high-contrast imaging, thus leveraging biophotonics and lab-on-a-chip devices and facilitating life-science applications.展开更多
Production of economically viable bioethanol is potentially an environmentally and financially worthwhile endeavor.One major source for fermentable sugars is lignocellulose.However,lignocellulosic biomass is difficult...Production of economically viable bioethanol is potentially an environmentally and financially worthwhile endeavor.One major source for fermentable sugars is lignocellulose.However,lignocellulosic biomass is difficult to degrade,owing to its inherent structural recalcitrance.Cellulosomes are complexes of cellulases and associated polysaccharide-degrading enzymes bound to a protein scaffold that can efficiently degrade lignocellulose.Integration of the enzyme subunits into the complex depends on intermodular cohesin-dockerin interactions,which are robust but nonetheless non-covalent.The modular architecture of these complexes can be used to assemble artificial designer cellulosomes for advanced nanotechnological applications.Pretreatments that promote lignocellulose degradation involve high temperatures and acidic or alkaline conditions that could dismember designer cellulosomes,thus requiring separation of reaction steps,thereby increasing overall process cost.To overcome these challenges,we developed a means of covalently locking cohesin-dockerin interactions by integrating the chemistry of SpyCatcher-SpyTag approach to target and secure the interaction.The resultant cohesin-conjugated dockerin complex was resistant to high temperatures,SDS,and urea while high affinity and specificity of the interacting modular components were maintained.Using this approach,a covalently locked,bivalent designer cellulosome complex was produced and demonstrated to be enzymatically active on cellulosic substrates.The combination of affinity systems with SpyCatcher-SpyTag chemistry may prove of general use for improving other types of protein ligation systems and creating unconventional,biologically active,covalently locked,affinity-based molecular architectures.展开更多
The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensure...The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensures the reduction of energy consumption, optimal operation of the smart grid and coordination between all smart grids’ components from generation to the end users. This paper presents an overview of existing communication technologies such as ZigBee, WLAN, cellular communication, WiMAX, Power Line Communication (PLC), their implementation in smart grids, advantages and disadvantages. Moreover, the paper shows comparison of communication infrastructure between the legacy grid and the smart grid and smart grid communication standards. The paper also presents research challenges and future trends in communication systems for smart grid application.展开更多
基金supported by Thailand Science Research and Innovation and the National Research Council of Thailand under Grant RGU6280014.
文摘This paper presents a theoretical and experimental study on controller design for the AMBs in a small-scale flywheel energy storage system,where the main goals are to achieve low energy consumption and improved rotordynamic stability.A H-infinity optimal control synthesis procedure is defined for the permanent-magnet-biased AMB-rotor system with 4 degrees of freedom.Through the choice of design weighting functions,notch filter characteristics are incorporated within the controller to reduce AMB current components caused by rotor vibration at the synchronous frequency and higher harmonics.Experimental tests are used to validate the controller design methodology and provide comparative results on performance and efficiency.The results show that the H-infinity controller is able to achieve stable rotor levitation and reduce AMB power consumption by more than 40%(from 4.80 to 2.64 Watts)compared with the conventional PD control method.Additionally,the H-infinity controller can prevent vibrational instability of the rotor nutation mode,which is prone to occur when operating with high rotational speeds.
文摘The current research joins previous studies in examining post-traumatic stress disorder (PTSD) and burnout among healthcare workers. The research focuses on the experiences of pediatric residents working in an emergency department both in normal times and during the Covid pandemic. Research conducted prior to and during the Covid pandemic outbreak shows negative psychological effects among healthcare workers. Most of that research was conducted within the positivistic-quantitative paradigm. The current study is qualitative and focuses on pediatric residents who provide medical services to a unique population in a peripheral region of Israel, namely the Bedouin-Arab population. The research questions are the following: What characterizes pediatric residents’ work, in general and during the pandemic? Do they show signs of burnout and secondary trauma? How do they perceive their work with the Bedouin-Arab population, especially during the pandemic? The study, conducted within the phenomenological genre, included 14 pediatric residents in a large hospital in Israel’s periphery. Semi-structured clinical interviews were employed, in addition to questionnaires that examined PTSD and burnout to enhance the reliability of the findings. The results show that all residents reported stressful incidents in which patients’ physical integrity was threatened. The residents described the special nature of the medical cases they treated in routine times and during the pandemic outbreak, which stems mostly from the specific characteristics the population of Israel’s periphery. While at the early stages of the pandemic, the residents experienced reduced work pressure, they reported substantial difficulties later in the crisis, which intensified their sense of physical and emotional stress. Most residents reported feeling inadequately prepared for dealing with traumatic events. According to the results, most residents displayed secondary trauma (12 participants in interviews and 11 in questionnaires), which can be classified into categories based on the DSM-5. In the interviews, all 14 participants reported various signs of burnout. The questionnaires indicated burnout symptoms among 10 participants. Giving a voice to pediatric residents, the study highlights the complexity of their routine work as well as their role during the Covid crisis. Based on the findings, recommendations have been made for policymakers. The study highlights the importance of raising awareness to the implications of the residents’ rough work conditions in routine and emergency times and to the need to develop social support and intervention programs that might improve their well-being during their professional work.
文摘The integration between vertical-cavity surface-emitting lasers and metasurfaces has been demonstrated to enable on-chip high-angle illumination for total internal reflection and dark-field microscopy. Such an ultracompact combined laser-beam shaper system provides a versatile illumination module for high-contrast imaging, thus leveraging biophotonics and lab-on-a-chip devices and facilitating life-science applications.
基金Russian Foundation for Basic Research and Japan Society for the Promotion of Science for support within the grantRFBR(12-02-92107-ЯФ)Israeli Ministry of Science&Technology(3-9754)
文摘Production of economically viable bioethanol is potentially an environmentally and financially worthwhile endeavor.One major source for fermentable sugars is lignocellulose.However,lignocellulosic biomass is difficult to degrade,owing to its inherent structural recalcitrance.Cellulosomes are complexes of cellulases and associated polysaccharide-degrading enzymes bound to a protein scaffold that can efficiently degrade lignocellulose.Integration of the enzyme subunits into the complex depends on intermodular cohesin-dockerin interactions,which are robust but nonetheless non-covalent.The modular architecture of these complexes can be used to assemble artificial designer cellulosomes for advanced nanotechnological applications.Pretreatments that promote lignocellulose degradation involve high temperatures and acidic or alkaline conditions that could dismember designer cellulosomes,thus requiring separation of reaction steps,thereby increasing overall process cost.To overcome these challenges,we developed a means of covalently locking cohesin-dockerin interactions by integrating the chemistry of SpyCatcher-SpyTag approach to target and secure the interaction.The resultant cohesin-conjugated dockerin complex was resistant to high temperatures,SDS,and urea while high affinity and specificity of the interacting modular components were maintained.Using this approach,a covalently locked,bivalent designer cellulosome complex was produced and demonstrated to be enzymatically active on cellulosic substrates.The combination of affinity systems with SpyCatcher-SpyTag chemistry may prove of general use for improving other types of protein ligation systems and creating unconventional,biologically active,covalently locked,affinity-based molecular architectures.
文摘The smart grid is a new generation of standard power distribution grid. The communication infrastructure is critical for the successful operation of the modern smart grids. The use of communication technologies ensures the reduction of energy consumption, optimal operation of the smart grid and coordination between all smart grids’ components from generation to the end users. This paper presents an overview of existing communication technologies such as ZigBee, WLAN, cellular communication, WiMAX, Power Line Communication (PLC), their implementation in smart grids, advantages and disadvantages. Moreover, the paper shows comparison of communication infrastructure between the legacy grid and the smart grid and smart grid communication standards. The paper also presents research challenges and future trends in communication systems for smart grid application.
