The Effects of Blowing Over Various Trailing-edge Flaps on an NACA 0006 Airfoil Section, Comparisons with Various Types of Flaps on other Airfoil Sections, and an Analysis of Flow and Power Relationships for Blowing Systems

The results are presented of a two-dimensional investigation conducted to determine the effect of blowing over various types of trailing-edge flaps on a wing having the NACA 0006 airfoil section and a drooped-nose flap. The position and profile of the trailing-edge flap, the nozzle height, and the location of the flap with respect to the nozzle were found to be important variables. Data from many investigations were used to make an evaluation of the effects of blowing on lift. An analysis was made of flow and power relationships for blowing systems

Securing a Stand of Clover on the Southern Iowa Loess

At the Sub-station at Leon, Decatur County, conducted by the Soil Section of the Iowa Experiment Station, clover was sown on the series of oat plots in the spring of 1905, some of the plots being treated with stable manure. It was noted during the season that the manured plots had the best stand, and much the best growth of clover. This is not a new discovery, but the cause seems to be a matter of speculation and conjecture. Clover is an important crop in Iowa, and is especially needed in that part of the State to supply lost humus and restore productiveness. Furthermore, it is often very difficult to get a good stand there especially on the points and clay hillsides

The Action of Manure on a Certain Iowa Soil

The soil on which these studies were made was Southern Iowa loess from the experiment field in Decatur County, Iowa. It is a fine loess soil containing considerable clay with the silt, and enough organic matter in the surface to make it dark brown. This loess differs from that of both eastern and western Iowa in its color, which is grey rather than yellow. It is the prevailing type of soil in southern Iowa. The field from which the sample was taken had been in cultivation thirty or forty years, and in that time had probably produced no clover crops. The productiveness was quite low owing to continuous cropping with grain and poor cultural methods

An assessment of an F2 or N2O4 atmospheric injection from an aborted space shuttle mission

Assuming a linear relationship between the stratosphere loading of NOx and the magnitude of the ozone perturbation, the change in ozone expected to result from space shuttle ejection of N2O4 was calculated based on the ozone change that is predicted for the (much greater) NOx input that would accompany large-scale operations of SSTs. Stratospheric fluorine reactions were critically reviewed to evaluate the magnitude of fluorine induced ozone destruction relative to the reduction that would be caused by addition of an equal amount of chlorine. The predicted effect on stratospheric ozone is vanishingly small

Little Cucuteni pots of hope: a challenge to the divine nature of figurines

Discussion of figurines is one of the most popular topics in the prehistory of Eastern Europe. They have been perceived as goddesses and gods, toys, individuals, dividuals, comforting miniatures, embodying personhood and more recently as “teaching devices”. Their relationship to fecundy and fertility is over-exploited but a safe haven for the majority of East European archaeologists. Here, we take on exactly the opposite view and try to build a case in which a set of figurines and a number of accompanying objects are interpreted as infertility aid-kits. The sets from Poduri-Dealul Ghindaru and Isaiia-Balta Popii are assessed in terms of recent tendencies in Western archaeological thought whereby representation and imposed meaning gives way to agency, action and performance. Rezumat: Figurinele reprezintă unul dintre cele mai preferate subiecte din preistoria Europei de Est. Acestea au fost percepute ca zeițe și zei, jucării, indivizi, divizi, miniaturi aducătoare de confort – încorporând personalitatea, și mai recent ca “instrumente de învățare”. Relația lor cu fecunditatea și fertilitatea este supralicitată, dar se constituie într-un rai sigur pentru majoritatea arheologilor est-europeni. În textul de față, adoptăm o perspectivă exact opusă și încercăm să construim un caz în care un set de figurine și un număr de obiecte asociate sunt interpretate drept seturi-de-ajutor împotriva infertilității. Seturile de la Poduri-Dealul Ghindaru și Isaiia-Balta Popii sunt evaluate în termenii tendințelor recente din gândirea arheologică Apuseană, în care reprezentarea și impunerea de sens lasă locul agenței, acțiunii și performării

The window of visibility: A psychological theory of fidelity in time-sampled visual motion displays

Many visual displays, such as movies and television, rely upon sampling in the time domain. The spatiotemporal frequency spectra for some simple moving images are derived and illustrations of how these spectra are altered by sampling in the time domain are provided. A simple model of the human perceiver which predicts the critical sample rate required to render sampled and continuous moving images indistinguishable is constructed. The rate is shown to depend upon the spatial and temporal acuity of the observer, and upon the velocity and spatial frequency content of the image. Several predictions of this model are tested and confirmed. The model is offered as an explanation of many of the phenomena known as apparent motion. Finally, the implications of the model for computer-generated imagery are discussed

Textural evolution of partially-molten planetary materials in microgravity

Recent Earth-based experiments examining the textural evolution of partially-molten rocks have revealed two important ways in which surface energy considerations affect magma. An initial experimental program addressing surface-energy effects on partially-molten materials in microgravity would involve simple, isothermal treatment of natural samples (meteorites, perioditic komatiite) at preselected temperatures in the melting range. Textural evolution would be assessed by time studies in which the only experiment variable would be run duration. Textural characterization of each sample would be done by quenching, recover, and sectioning for generally later, computer-aided interpretation of features

On the Use of Group Theoretical and Graphical Techniques toward the Solution of the General N-body Problem

Group theoretic and graphical techniques are used to derive the N-body wave function for a system of identical bosons with general interactions through first-order in a perturbation approach. This method is based on the maximal symmetry present at lowest order in a perturbation series in inverse spatial dimensions. The symmetric structure at lowest order has a point group isomorphic with the S_N group, the symmetric group of N particles, and the resulting perturbation expansion of the Hamiltonian is order-by-order invariant under the permutations of the S_N group. This invariance under S_N imposes severe symmetry requirements on the tensor blocks needed at each order in the perturbation series. We show here that these blocks can be decomposed into a basis of binary tensors invariant under S_N. This basis is small (25 terms at first order in the wave function), independent of N, and is derived using graphical techniques. This checks the N^6 scaling of these terms at first order by effectively separating the N scaling problem away from the rest of the physics. The transformation of each binary tensor to the final normal coordinate basis requires the derivation of Clebsch-Gordon coefficients of S_N for arbitrary N. This has been accomplished using the group theory of the symmetric group. This achievement results in an analytic solution for the wave function, exact through first order, that scales as N^0, effectively circumventing intensive numerical work. This solution can be systematically improved with further analytic work by going to yet higher orders in the perturbation series.Comment: This paper was submitted to the Journal of Mathematical physics, and is under revie

Children’s Independent Mobility: an international comparison and recommendations for action

This report is the latest in a series looking at the personal mobility and travel patterns of children. The first was published in 1971, looking at children’s mobility in England. A follow-up study, published in 1990, expanded the survey to look at children in what was then West Germany. A third study looking at childhood mobility was published in 2010, providing a unique set of longitudinal data, stretching over four decades. The changes in children’s independent mobility have been striking. For example, in 1971 in England, 55 per cent of children under 10 were allowed to travel alone to places other than school that were within walking distance; by 2010, almost no children under 10 were allowed to do so. This report expands the available data geographically, covering 16 countries: Australia, Brazil, Denmark, England, Finland, France, Germany, Ireland, Israel, Italy, Japan, Norway, Portugal, South Africa, Sri Lanka and Sweden. The children involved were aged from seven to 15