The orbital siphon : A new space elevator concept

A new concept for propellantless payload transfer from the surface of the Earth to Earth escape is presented. Firstly, a simple model of a payload ascending or descending a conventional space elevator is developed to explore the underlying dynamics of the problem. It shown that an unconstrained payload at rest on a space elevator at synchronous radius is in an unstable equilibrium, and that this instability can be used to motivate the development of a new concept for payload transfer. It will be shown that a chain of connected payloads stretching from the surface of the Earth to beyond synchronous radius can be assembled which will lift new payloads at the bottom of the chain, while releasing payloads from the top of the chain. The complete system therefore acts as an 'orbital siphon', transporting mass from the surface of the Earth to Earth escape without the need for external work to be done. Indeed the system performs net work by transferring energy from the Earth's rotation to the escaping mass. The dynamics of the siphon effect are explored and key engineering issues are identified

Novel payload dynamics on space elevator systems

A simple model of a payload ascending or descending a space elevator is developed to explore the underlying dynamics of the problem. It shown that an unconstrained payload at rest on a space elevator at synchronous radius is in an unstable equilibrium, and that this instability can be used to motivate the development of new ideas for payload transfer. In particular, it will be shown that a chain of connected payloads can be assembled which will lift new payloads at the bottom of the chain, while releasing payloads from the top of the chain. The system therefore acts as an 'orbital siphon', transporting mass from the surface of the Earth to escape speed without the need for external work to be done

The Declining Number of Youth in Custody in the Juvenile Justice System

During the last decade, custody rates for youth in the US have declined significantly. This Focus describes this trend by race/ethnicity, gender, and state. Measured by arrest rates, juvenile crime, especially serious crime, has also decreased during this period, contrary to a prevalent misconception that young people pose a growing threat to society

The WiggleZ Dark Energy Survey: constraining the evolution of Newton's constant using the growth rate of structure

We constrain the evolution of Newton's constant using the growth rate of large-scale structure measured by the WiggleZ Dark Energy Survey in the redshift range $0.1 < z < 0.9$. We use this data in two ways. Firstly we constrain the matter density of the Universe, \omms (assuming General Relativity), and use this to construct a diagnostic to detect the presence of an evolving Newton's constant. Secondly we directly measure the evolution of Newton's constant, \Geff, that appears in Modified Gravity theories, without assuming General Relativity to be true. The novelty of these approaches are that, contrary to other methods, they do not require knowledge of the expansion history of the Universe, $H(z)$, making them model independent tests. Our constraints for the second derivative of Newton's constant at the present day, assuming it is slowly evolving as suggested by Big Bang Nucleosynthesis constraints, using the WiggleZ data is \ddotGeff(t_0)=-1.19\pm 0.95\cdot 10^{-20}h^2 \textrm{yr}^{-2}, where $h$ is defined via $H_0=100 h km s^{-1}Mpc^{-1}$, while using both the WiggleZ and the Sloan Digital Sky Survey Luminous Red Galaxy (SDSS LRG) data is \ddotGeff(t_0)=-3.6\pm 6.8\cdot 10^{-21}h^2 \rm{yr}^{-2}, both being consistent with General Relativity. Finally, our constraint for the rms mass fluctuation $\sigma_8$ using the WiggleZ data is $\sigma_8=0.75 \pm 0.08$, while using both the WiggleZ and the SDSS LRG data $\sigma_8=0.77 \pm 0.07$, both in good agreement with the latest measurements from the Cosmic Microwave Background radiation.Comment: 15 pages, 5 figures, 4 tables, changes match the published versio

Community-Based Learning Projects for the Real World

As we walked down the street to the next-door elementary school, the I 5 high school juniors with me began reflecting on their elementary school experiences. They remembered the Dr. Seuss stories their teachers had read to them, the art projects, the time to play, the time to just be kids. Life was simpler and more fun then, they all agreed. Now school mostly means sitting at desks and listening to teachers talk for a large portion of the day. And when teachers aren\u27t talking to them, they take tests, read a textbook chapter, write on a ditto, watch a film. On occasion they might be asked to discuss issues and ideas in large and small group discussions, but mostly their role is that of consumers of knowledge dispensed by their teachers. What they do produce usually has value only to their teacher since the teacher is the only person to ever see or grade the work

2015 AQ Summit: Oyster Sub-sector Update

A brief summary of the condition of the oyster sub-sector of aquaculture in Maine

The Long-Term Effects of Divorce and Parental Discord on the Adult-Child\u27s Socioeconomic Attainment

Some of the most recent divorce research suggests that a better descriptor of adult socioeconomic attainment is not divorce, nor its intermediary causes, but rather the existence of hostile and aggressive parental behavior during childhood (Keister, 2005; Amato, 2005). Accordingly, divorce may just be another measure of a more significant cause of diminished income attainment among children of divorce: poorly managed anger by parents. The present study seeks to explore these complex relationships and establish that the parental relationships in a household are as important as the legal outcome of the marriage itself with regard to long run adultchild effects