Integrated investigation of piston–cylinder impact-induced noise and passive control of the piston’s secondary motion using nonlinear absorbers

Although alternative power sources are getting well-established, transportation will remain primarily dependent on IC engines using fossil fuels for at least a few more decades. The IC engines typically employ reciprocating pistons to convert the combustion pressure into mechanical work required by the vehicle. Engine NVH issues make their appearance at the piston-cylinder interface in the form of impulsive vibration signals. The piezo-viscous nature of the lubricant at the piston-cylinder conjunction can change the dynamic response of the impacting structures. Much of the published research to date has excluded the elasto-hydrodynamic effects of the lubricant on piston impact noise. Even when these effects were studied, the research focus has been primarily on the tribology of the contact. Thus, an accurate methodology is required to identify and predict piston impact noise using real in-cylinder conditions, especially at the lubricated piston-cylinder conjunction. [Continues.

Gate-Controlled Quantum Dots in Two-Dimensional Tungsten Diselenide and One-Dimensional Tellurium Nanowires

This work focuses on the investigation of gate-defined quantum dots in two-dimensional transition metal dichalcogenide tungsten diselenide (WSe2) as a means to unravel mesoscopic physical phenomena such as valley-contrasting physics in WSe2 flakes and its potential application as qubit, as well as realizing gate-controlled quantum dots based on elementaltellurium nanostructures which may unlock the topological nature of the host material carriers such as Weyl states in tellurium nanowires.The fabrication and characterization of gate-defined hole quantum dots in monolayer and bilayer WSe2 are reported. The gate electrodes in the device design are located above and below the WSe2 nanoflakes to accumulate a hole gas. For some devices we additionally used gates to deplete the gas to define the dot. Temperature dependence of Coulomb-blockade peak height complies with single-level transport and the small size of the dot leads to observation of excited states in the Coulomb diamond measurements. Further, magnetic field dependence of the excited states in the bilayer devices provides a lower bound for g factors. For the chiral crystals of elemental Te, the intriguing property of combining Weyl physics with a small semiconducting bandgap enables the creation of gate-tunable devices to probe and utilize the topological properties of Te. The formation of gate-defined quantum dots in Te would allow Coulomb blockade spectroscopy to provide information about the strength of exchange interaction, spin-orbit coupling, and g-factors associated with discrete quantum states in Te nanostructures. Using low-pressure physical vapor deposition, Te nanowires are grown that permits local control of carrier density using electrostatic gates. While atomically flat hexagonal boron nitride (hBN) gate dielectrics haves been widely used for high quality layered material devices, the relatively weak adhesion to Te nanowires makes hBN-insulated Te device assembly challenging. Therefore, the configuration of the device underwent a few iterations. The gate electrodes design and insulating strategy compare different methods involving more traditional dielectrics, as well as a hybrid approach that uses a global Si backgate and hBN-insulated local top gates for these Weyl semiconductor devices. Early measurements of Te devices demonstrate density control in these devices. Future work must be aimed at quantum transport measurements in Te dots

Use of XPS thermal insulator boards in design of educational spaces

This research refers to case study, Haghpanah girls' primary school that is of the standard schools designed and implemented by Isfahan Province Schools Renovation Organization. It deals to the importance and creation of an operational method for applying modern materials such as XPS thermal insulator in architectural design and its effect on educational spaces in section of primary school and how to design. It also deals to its effect and advantages on interior spaces that will help educational optimization significantly. Perhaps some believe that the implementation of thermal insulation of the building increases construction costs. However, we note that the implementation of thermal insulation not only saves energy consumption but also has a significant role in consumption of wasted heating and cooling energy of educational spaces. For example, the position of mentioned school is on the ground floor (pilot) and with external walls around the building. As it is obvious, the building floor and three sides of its perimeter are a part of the external shell (in contact with the outside perimeter). Cooling and heating of such a building requires spending high costs to provide equipment with high capacities. Heating and cooling equipment capacity becomes smaller than half after proper implementation of thermal insulation.As air conditioning equipment becomes small, implementation of optimization not only becomes free but also reduces the overall cost of construction.Keywords: School, modern materials, Building and Housing Research Center, XPS board

On the modeling of viscoelastic droplet impact dynamics

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this paper, a numerical modeling of the impact, spreading, and eventually rebound of a viscoelastic droplet is reported. The numerical model is based on the volume of fluid (VOF) method coupled with the FENE-CR constitutive equations, and accounts for both the surface tension and the substrate wettability. The FENE-CR constitutive equations are used to model the polymer solution, while taking advantage of its rheological characterization. The comparison is performed between droplets of Newtonian solvent and a monodisperse polymer solution. The droplet impact on both hydrophilic and superhydrophobic substrate is analyzed through a detailed analysis of the spreading diameter evolution. It is found that while the droplet kinematic phase seems independent of the substrate and fluids properties, the recoiling phase is highly related to all of them. In addition the model infers a critical polymer concentration above which the droplet rebound from a superhydrophobic substrate is suppressed. The simulation is of particular interest to ink-jet processing, and demonstrates the capability of the model to handle complex non-Newtonian droplet dynamics

Emergency nurses' requirements for disaster preparedness

Background: Natural and man-made disasters affect people, communities, and health systems. Nurses play a key role in the health system and must be prepared for appropriate response in disasters. Objectives: This study was done to assess the current knowledge of nurses in emergency departments for disaster preparedness. Patients and Methods: This cross-sectional study was conducted on 110 emergency nurses working in teaching hospitals affiliated to Iran University of Medical Sciences, Tehran, Iran. A questionnaire was used to collect data and the data were then analyzed using descriptive and inferential statistics with SPSS software version 16.0. Results: Based on the findings, most of the participants (64.5) were aged 30 - 39 years old. 84 of the cases were female and 97.3 had a bachelor's degree. The average perceived knowledge of nurses was 2.43 ± 1.01. The nurses had the highest familiarity with triage and lowest knowledge in epidemiology and decision-making. Conclusions: Lack knowledge of nurses regarding response to disaster situations indicates inefficiencies in the current system. Therefore, it is recommended to organize more workshops, annual training courses, and maneuvers based on staff needs and formulate continuous education courses for nurses. Copyright © 2015, Trauma Monthly

"Teacher...could you please allow us to play outside.." landscape design for children outdoor educational center

Playing in the outdoor kindergarten environment provides unique opportunities for children in the critical period of early childhood. However; such experiences became less in compare to children‘s indoor educational activities, as the conventional ―equipment based‖ playground does not fulfill the requirements of being outdoors. At the same time, preschool children‘s participation in design is poorly noticed as they are considered inadequate to recognize their own needs. The research hypothesizes that an understanding of children‘s perception of their kindergarten play yard can ensure their emotional satisfaction and increases their physical behavior. This study investigated preschooler‘s preferred outdoor learning elements and activities in UPM kindergarten (FACE). This study adopted photo elicitation method including children and teachers interview. The findings suggested that children have shown their own desire towards outdoor activities and play elements. Majority of the children prefer free play in natural play environment that incorporated sustainable elements with natural composition. Natural play environment was found to able to help in increasing their desire for outdoor activities and at the same time, addressed the health and learning issues. Having more time spent with free creative and cognitive activities in natural play area will then, promote awareness of natural environment, better health and learning condition of the children