Dynamics of an experimental two bladed horizontal axis wind turbine with blade cyclic pitch variation

The turbine under study incorporates the combination of two features: the application of blade cyclic pitch variation; and the use of yaw angle control for rotor speed and torque regulation. Due to its emasculation by passive cyclic pitch variation the rotor can be rapidly yawed without encountering gyroscopic and aerodynamic hub moments and without noticeable out of plane excursions. The two bladed upwind rotor is vane stabilized and of very simple and rugged design. The principle was first checked out with a small scale wind tunnel model and then tested in the atmosphere with a 7.6 meter diameter experimental fully instrumented wind turbine driving a 3 phase alternator. The test results are summarized with respect to structural dynamics and yaw dynamics

A comparison of the haemodynamic and cardic autonomic responses following an acute bout of isometric wall squat and isometric handgrip exercise

Purpose. Isometric exercise (IE) training has been shown to be effective at reducing resting blood pressure (BP). However, there is a lack of clarity as to which IE modality is more effective at reducing resting BP. Acute responses following a single session of IE have been shown to predict long-term training adaptions. It was hypothesised that when using a comparative workload, exercises that recruit more muscle mass have a greater proclivity to induce transient reductions in BP than those that use smaller amounts of muscle mass. To test this hypothesis, the current study set out to compare the acute haemodynamic and autonomic responses following a single session of isometric wall squat (IWS) and isometric handgrip (IHG). Method. Twenty-six sedentary participants performed a single IWS and IHG session comprised of 4 x 2-min contractions, with 2-min rest, at 95 HRpeak and 30% MVC, respectively. Total power spectral density of HR variability and associated low-frequency and high-frequency power spectral components were recorded in absolute and normalized units before, during, and 10-min and 1hour after each IE session. Heart rate (HR) was recorded via electrocardiography and baroreceptor reflex sensitivity via the sequence method. Continuous BP was recorded via the vascular unloading technique and stroke volume and cardiac output (Q̇) via impedance cardiography. Total peripheral resistance (TPR) was calculated according to Ohm’s law. The change from baseline for each variable was used for comparative analysis. Results. During IE, there was a significantly greater increase in systolic BP, diastolic BP, mean BP, HR and Q̇ in the IWS condition (all P= <0.001). There was also significantly less TPR during IWS exercise (P= 0.006). During the 10-min recovery window, there was a significantly greater reduction in systolic BP, diastolic BP, mean BP (all P= 0.005) and TPR (P= <0.001). There were no differences in any autonomic variables during recovery, and no differences in any variables 1-hour post exercise. Conclusion. Isometric wall squat exercise produces a greater cardiovascular response during exercise, with a greater reduction in BP and TPR during a 10-min recovery period. These acute responses may be mechanistically linked to the chronic reductions in resting BP reported after IE training interventions

First record of Curius chemsaki Nearns and Ray, 2006 (Coleoptera: Cerambycidae: Cerambycinae: Curiini) in Colombia

Curius chemsaki Nearns and Ray, 2006 (Coleoptera: Cerambycidae: Cerambycinae: Curiini), is reported from Colombia for the first time. In addition, the range of this taxon within Venezuela is extended to the Andean Province of Táchira

Designing dual-plate meteoroid shields: A new analysis

Physics governing ultrahigh velocity impacts onto dual-plate meteor armor is discussed. Meteoroid shield design methodologies are considered: failure mechanisms, qualitative features of effective meteoroid shield designs, evaluating/processing meteoroid threat models, and quantitative techniques for optimizing effective meteoroid shield designs. Related investigations are included: use of Kevlar cloth/epoxy panels in meteoroid shields for the Halley's Comet intercept vehicle, mirror exposure dynamics, and evaluation of ion fields produced around the Halley Intercept Mission vehicle by meteoroid impacts

The Use of Quantitative and Qualitative Analysis in the General Chemistry Laboratory

Author Institution: California Institute of Technology, Pasadena, Californi

It\u27s a Little Scar : A Phenomenological Study of Nurses\u27 Responses Following Direct Involvement in a Nursing Error

The frequency of errors in the healthcare environment is staggering, and nurses are often responsible for potentially or actually inflicting unintentional harm on patients. The patient and family are the first victims of a nursing error, but the incident can be a traumatic experience for the nurse as well, establishing him or her as a second victim. The purpose of this phenomenological research study is to describe the lived experience of nurses as a second victim following involvement in an unanticipated nursing error. The study is grounded in the existential phenomenological philosophy of Merleau-Ponty and guided by research procedures developed by Thomas and Pollio (2002). The study answers the question: How do nurses involved in an unintentional nursing error perceive and describe their response to the experience as a second victim? The research design methodology included a purposeful networking approach to recruit participants. In-depth, unstructured phenomenological interviews were conducted with 12 nurses willing to be interviewed about their personal, direct involvement in an unanticipated nursing error, with or without patient injury. Participants ranged in age from 24 to 64 years, and length of nursing experience at time of the error ranged from one month to 30 years. Data analysis included reading and analyzing all transcripts for meaning units and global themes to develop the thematic structure. The researcher, Interpretive Research Group, and willing participants agreed upon the final thematic structure. An encompassing central theme of “it’s a little scar” was woven throughout the interviews as participants described their experience. Four figural themes manifested within this central theme: (1) “That was a traumatic experience”; (2) “My god, am I still competent?”; (3) “They did not treat me bad” – “I am being thrown under the bus”; and (4) “I still think about it.” Study rigor was maintained through bracketing, data saturation, peer debriefing, member checking, and the use of direct quotes to support findings. This research offers an intensified awareness of what it is truly like to live as a nurse following involvement in a nursing error. Findings add to the nursing literature and have implications for nursing education, practice, and policy

Rigidity Modulus of Lead Single Crystals (Abstract)

The isothermal rigidity modulus has been measured for lead crystals of various orientations. The reciprocal bending-torsion effect and its influence on the measurement are considered