Bays in Peril: A Forecast for Freshwater Flows to Texas Estuaries

Takes a look at increasing water demands in Texas, and what would happen to the inflows to the seven major estuaries if existing water permits were fully used and wastewater reuse increased. Provides recommendations for action

Two Screen Viewing and Social Relationships. Exploring the invisible backchannel of TV viewing

Use of social networks to create a real-time backchannel of\ud communication among viewers of television programs has been documented, and has been termed “two-screen viewing,” with one screen devoted to the program being watched, and a second screen (usually a laptop, tablet, or cell/mobile\ud phone) devoted to maintaining the backchannel. Prior research has examined twoscreen viewing through content analysis of social media posts. However, little has been done to explore the way in which two screen viewing qualitatively changes the viewing experience, or to understand how this behavior contributes to the construction or maintenance of social relationships. Couch (1992) noted that social interaction require a shared focus, a social objective, and congruent functional identities. The first screen program provides the shared focus. Using online interviews, this small pilot project seeks to discover whether social objectives and congruent functional identities are established through two-screen viewing. That is, the study explores how one might go about determining whether this communication actually contributes to social relationships or serves some other, asocial purpose. The present study is a small pilot project only. Preliminary\ud data suggest that there are two types of two-screen viewing defined by different degrees of visible and invisible online practice

A Consistent Model of the Accretion Shock Region in Classical T Tauri Stars

We develop a consistent model of the accretion shock region in Classical T Tauri Stars (CTTSs). The initial conditions of the post-shock flow are determined by the irradiated shock precursor and the ionization state is calculated without assuming ionization equilibrium. Comparison with observations of the C IV resonance lines (λλ 1550 Å) for CTTSs indicate that the post-shock emission predicted by the model is too large, for a reasonable range of parameters. If the model is to reproduce the observations, C IV emission from CTTSs has to be dominated by pre-shock emission, for stars with moderate to large accretion rates. For stars with low accretion rates, the observations suggest a comparable contribution between the pre- and post-shock regions. These conclusions are consistent with previous results indicating that the post-shock will be buried under the stellar photosphere for moderate to large accretion rates

Supersonic flutter of cylindrical shells

The general theories of thin elastic cylindrical shells as derived by Love and Novozhilov are compared and then used in a simple binary flutter analysis which permits the existence of both axial and circumferential waves of deformation. Linear piston theory has been used and the results obtained indicate that the axi-symmetric mode of deformation is the most critical. Comparisons are then made with other published results and apparent inconsistencies in those papers are found to arise from certain assumptions made in the deformation equations used. In a further axisymmetric mode analysis the use of a travelling wave form of radial deflection is shown to give similar results as standing wave forms when applied to a shell of finite length

Thermal stresses in thin cylindrical shells, stiffened by plane bulkheads, for arbitrary temperature distributions

A study has been made of the thermal stresses reulting near the joint of a cylinder and internal bulkhead due to arbitrary temperature distributions in the configuration and to the consequent compatability forces and moments at the joint. The method is general enough to permit the inclusion of joint thermal resistance but certain limitations are placed on the form of the axial temperature distribution in the cylinder. An approximate method to determine the transient temperatures for completely general heating programmes is also proposed

Optimum design of a multicell box subjected to a given bending moment and temperature distribution

The optimum geometry of a multicell box of given depth, under a given bending moment and temperature distribution, is obtained. The method is general enough to permit the skin thickness to be either specified, e.g. by stiffness requirements, or not

The flutter of thin, plane, elliptic panels

The effect of various parameters on the flutter of elliptic panels is studied by simple theoretical analyses. For clamped edge panels, compressive membrane stresses are shown to have destabilising effects. Structural damping is, in general, destabilising, except for very low values of the ratio of structural and aerodynamic damping coefficients. The addition of a concentrated mass may also have a destabilising effect, depending upon the position of the added mass. The effect of sweepback is stabilising or destabilising, depending on whether the panel aspect ratio is less than, or greater than, unity. The effect of variations in the edge conditions is shown for the case of circular panels where the difference between simply supported and fully clamped edges corresponds to a difference of 20% in critical panel thickness

Some design problems of thin shell structures

Simplified analyses are presented which illustrate some of the design problems of typical space vehicle structures, with the emphasis on thin, circular cylindrical shells. Amongst the problems considered are panel flutter, thermal buckling and buckling under axial compression

Supersonic flutter of cylindrical shells

The general theories of thin elastic cylindrical shells as derived by Love and Novozhilov are compared and then used in a simple binary flutter analysis which permits the existence of both axial and circumferential waves of deformation. Linear piston theory has been used and the results obtained indicate that the axi-symmetric mode of deformation is the most critical. Comparisons are then made with other published results and apparent inconsistencies in those papers are found to arise from certain assumptions made in the deformation equations used. In a further axisymmetric mode analysis the use of a travelling wave form of radial deflection is shown to give similar results as standing wave forms when applied to a shell of finite length