Propagating and evanescent internal waves in a deep ocean model

We present experimental and computational studies of the propagation of internal waves in a stratified fluid with an exponential density profile that models the deep ocean. The buoyancy frequency profile $N(z)$ (proportional to the square root of the density gradient) varies smoothly by more than an order of magnitude over the fluid depth, as is common in the deep ocean. The nonuniform stratification is characterized by a turning depth $z_c$, where $N(z_c)$ is equal to the wave frequency $\omega$ and $N(z < z_c) < \omega$. Internal waves reflect from the turning depth and become evanescent below the turning depth. The energy flux below the turning depth is shown to decay exponentially with a decay constant given by $k_c$, which is the horizontal wavenumber at the turning depth. The viscous decay of the vertical velocity amplitude of the incoming and reflected waves above the turning depth agree within a few percent with a previously untested theory for a fluid of arbitrary stratification [Kistovich and Chashechkin, J. App. Mech. Tech. Phys. 39, 729-737 (1998)].Comment: 13 pages, 4 figures, 4 table

INVESTIGATION OF ADHESION AND COHESION OF METALS IN ULTRAHIGH VACUUM.

Adhesion and cohesion of metals in ultrahigh vacuu

What about us?:Experiences of relatives during end-of-life cancer care and bereavement

Cancer affects not only the patient, but also the relatives. This is perhaps even more so at the patient's end of life. Relatives provide support to the patient and help with day-to-day care, which can be tough. The role of the relatives in providing care is becoming increasingly important, partly due to the increasing pressure on the professional health care system in the Netherlands. It is important to support relatives well, so that they can continue to provide the necessary care to the patient on the one hand and maintain the best possible quality of life themselves on the other hand. The aim of this thesis was therefore to gain insight into the experiences of relatives of patients with advanced cancer in the Netherlands. With this information, we can improve the support for relatives, which will hopefully ensure that their quality of life also improves. To answer the research questions of this thesis, data from two large (inter)national studies, registration data and a literature study were used.One of the conclusions of this thesis is that potentially inappropriate end-of-life care for patients with advanced cancer leads to a decrease in the well-being of relatives. An example of this potentially inappropriate end-of-life care is that the treating physician continues to give medication to the patient, while the risks of the medication are likely to outweigh the benefits in the last phase of life. It appears that almost half of all patients with lung cancer (45%) continue to receive this type of medication in the last month of life.A second key finding is that the well-being of relatives decreases in the last year of life of patients with advanced cancer and the number of relatives experiencing emotional problems increases. Many relatives need more support with psychological problems, as well as information about and support with patient care. In addition, the impact of cancer for relatives does not stop with the death of the patient. After the patient's death, more than 40% of the relatives experience emotional problems.Some of the research was carried out during the COVID-19 pandemic. During the pandemic, a lot changed in care and in the possibilities to support each other. Yet, this thesis found no differences in the well-being of bereaved relatives who had lost a loved one to cancer before or during the COVID-19 pandemic. Research conducted in Sweden did show that bereaved relatives who had not been able to carry out death rituals as desired during the COVID-19 pandemic fared worse.This thesis shows that it is important that we do not forget the relatives in palliative care both during the last phase of life and after the patient's death. Support for relatives can come from healthcare providers, but also from the social environment of relatives (e.g. family and friends) and from the wider community such as neighbors, work and church. For the care that relatives give to the patient, it is important that relatives are well informed about what they can expect during the disease process (e.g. what symptoms may occur) and how they can get support in this regard._Kanker heb je niet alleen. De ziekte heeft niet alleen invloed op de patiënt zelf, maar ook op diens naasten. Dat is misschien nog meer het geval rond het levenseinde van de patiënt. Naasten bieden steun aan de patiënt en helpen bij de dagelijkse zorg, wat zwaar kan zijn. De rol van naasten wordt steeds belangrijker, mede door de toenemende druk op de gezondheidszorg in Nederland. Het is belangrijk om naasten goed te ondersteunen, zodat ze enerzijds de nodige zorg aan de patiënt kunnen blijven geven en anderzijds zelf een zo goed mogelijke kwaliteit van leven behouden. Het doel van dit proefschrift was daarom om inzicht te krijgen in de ervaringen van naasten van patiënten met gevorderde kanker in Nederland. Met die informatie kunnen we de ondersteuning voor de naasten verbeteren, wat er hopelijk voor zorgt dat hun kwaliteit van leven ook verbetert. Om de onderzoeksvragen van dit proefschrift te beantwoorden zijn gegevens gebruikt van twee grote (inter)nationale studies, registratiedata en een literatuurstudie. Eén van de conclusies van dit proefschrift is dat mogelijk niet-passende zorg voor patiënten met gevorderde kanker er toe leidt dat het welzijn van naasten afneemt. Een voorbeeld van deze mogelijk niet-passende zorg is dat de behandelend arts medicatie aan de patiënt blijft geven waarvan de risico’s waarschijnlijk groter zijn dan de voordelen in de laatste levensfase. Het blijkt dat bijna de helft van alle patiënten met longkanker (45%) nog dit soort medicatie krijgt in de laatste maand van hun leven. Een tweede belangrijke conclusie is dat het welzijn van naasten afneemt in het laatste levensjaar van patiënten met gevorderde kanker en het aantal naasten dat emotionele problemen ervaart toe neemt. Veel naasten hebben meer behoefte aan ondersteuning bij psychologische problemen, maar ook aan informatie over en steun bij de zorg voor de patiënt. Daarnaast stopt de impact van kanker voor de naaste niet bij het overlijden van de patiënt. Na het overlijden van de patiënt ervaart ruim 40% van de nabestaanden emotionele problemen. Een deel van de onderzoeken is uitgevoerd tijdens de COVID-19-pandemie. Tijdens deze pandemie veranderde er veel in de zorg én in de mogelijkheden om elkaar te steunen. Toch werden er in dit proefschrift geen verschillen gevonden in het welzijn van nabestaanden die voor of tijdens de COVID-19-pandemie een geliefde waren verloren aan kanker. Uit onderzoek dat we in Zweden uitvoerden bleek wel dat het slechter ging met nabestaanden die tijdens de COVID-19-pandemie overlijdensrituelen niet hadden kunnen uitvoeren zoals ze graag hadden willen doen. Dit proefschrift laat zien dat het belangrijk is dat we in de palliatieve zorg de naasten niet vergeten zowel tijdens de laatste levensfase als ná het overlijden van de patiënt. De steun voor naasten kan komen van zorgverleners, maar ook van de sociale omgeving van naasten (bijvoorbeeld familie en vrienden) en van de bredere gemeenschap zoals buren, werk en kerk. Voor de zorg die naasten geven aan de patiënt is het belangrijk dat naasten goed geïnformeerd worden over wat ze kunnen verwachten tijdens het ziekteproces (bijvoorbeeld welke symptomen kunnen optreden) en hoe ze hierbij ondersteuning kunnen krijgen

MAST flight system dynamic performance

The MAST Flight System as a test bed for large space structure control algorithms is discussed. An overview is given of the control system architecture. The actuators, the sensors, the control computer, and the baseline damping algorithm are discussed

Report of the Secretary, 1942-45, inclusive

Detailed reports of the annual spring meetings of the Arkansas Academy of Science have been sent out to all members. Therefore, only a summary of Academy activities for a more permanent record will be reviewed. Further secretarial information will be found in tabular forms elsewhere. While the period under discussion has never been equaled before in history, the Academy has held meetings each spring, though on a smaller scale. In the meantime new evidence that the people of our part of the country sense the importance of research in industry may be seen in the new research organizations such as the University Bureau of Research, The Southern Association of Science and Industry, The Gulf of Southwest Industrial and Agricultural Conference, Inc. and the Midwest Research Institute

Wind Tunnel Generation of Sinusoidal Lateral and Longitudinal Gusts by Circulation of Twin Parallel Airfoils

A gust generator capable of producing sinusoidal lateral and longitudinal gusts was developed for the purpose of studying the gust response of a model rotor-propeller in a wind tunnel. The gust generator utilized harmonic circulation control of twin parallel airfoils to achieve the harmonic lift variation required for gust generation. The gust generator design, construction, and testing is described. Typical test results are presented in the form of lateral and longitudinal gust perturbation velocities as a function of generator reduced frequency

Aerodynamic interference effects on tilting proprotor aircraft

The Green's function method was used to study tilting proprotor aircraft aerodynamics with particular application to the problem of the mutual interference of the wing-fuselage-tail-rotor wake configuration. While the formulation is valid for fully unsteady rotor aerodynamics, attention was directed to steady state aerodynamics, which was achieved by replacing the rotor with the actuator disk approximation. The use of an actuator disk analysis introduced a mathematical singularity into the formulation; this problem was studied and resolved. The pressure distribution, lift, and pitching moment were obtained for an XV-15 wing-fuselage-tail rotor configuration at various flight conditions. For the flight configurations explored, the effects of the rotor wake interference on the XV-15 tilt rotor aircraft yielded a reduction in the total lift and an increase in the nose-down pitching moment. This method provides an analytical capability that is simple to apply and can be used to investigate fuselage-tail rotor wake interference as well as to explore other rotor design problem areas