Solid-state combustion synthesis of ceramics and alloys in reduced gravity

Possible microgravity effects are explored in the combustion synthesis of ceramics and alloys from their constituent elements. Molten intermediates are typically present during the combustion process, thereby offering the chance for natural convection to take place. Numerical simulations suggest that the combustion front in concert with gravity may act as a partial zone-refinement mechanism which is attempting to sweep out porosity in the sample. Contrary to suggestions by dimensional analysis, no effects on the combustion rate are seen. An analytical model of the combustion velocity as a function of the gravitational field and the spreading rate of molten material gives the correct order of magnitude of the gravity effect as measured by centrifuge experiments

MEDITATION TODAY: SCIENCE AND SHORTCUTS

A daily practice for millions of people around the world, akin to prayer, meditation is now welcome in many professional areas such as psychoneuroimmunology that have proven its efficacy. Medical doctors like D.S. Khalsa, say that meditation produces “optimal cognitive function” and have found that it is positively rejuvenating for the brain and physiologically harmonizing for the body. This article is an outgrowth of presentations to audiences at the U.S. Patent and Trademark Office and the U.S. Psychotronics Association.* It provides an introduction to the practice of meditation for Westerners, with some science and shortcuts

Effect of humidity on the creep response of cellulose nanocrystals films

Cellulose nanocrystals (CNCs) are a derivative of cellulose, the Earth’s most abundant source of a sustainable polymer. There are many applications for CNCs such as batteries, antimicrobial films, flexible displays and drug delivery. This research is focused on CNCs films and the mechanical properties once humidity was introduced. The creation of self-aligned CNCs films was utilized to perform dynamic mechanical analysis (DMA) testing. The Forest Products Lab (FPL) in Madison, Wisconsin provided the CNCs used. Both 3.5 wt.% and 9.1 wt.% films were made and tested. A DMA method was created to test the creep response of the CNCs films at humidity levels of 80%, 40% and 0%. This method was performed at both 30°C and 50°C. Before and after the films were tested in the DMA, optical microscopy images were taken to analyze the structure of the films. It was found that the films experienced a higher strain rate at 30°C, but regardless of temperature the trend of strain was non-linear, with the highest strain reached at 80% humidity. There was full creep recovery at 40% humidity and shrinkage of the films once the humidity level reached 0%

Global Environmental Forecast and Roadmap Based on 420 kY of Paleoclimatology

As the world’s population has tripled (3x) since 1950, with another 50% increase expected by 2100, global annual carbon dioxide emissions growth rate has quadrupled (4x) since 1950 and global energy demand has quintupled (5x), all in the same time period. This discontinuous combination can be called a “3-4-5 Triad” and the sudden acceleration in all three arenas is too stressful on the environment and the damaging effects will be felt globally for centuries to come unless drastic action is taken. More importantly, the energy demand at 5x is outstripping the other two. This clearly means that as the population explodes at 3x, the emerging middle class wants almost twice as much as their usual share as fossil-fueled generators spread around the globe and modern conveniences become more and more desirable. However, such energy demand at 5x is an artificial human need that is predicted by RMI.org to result in four to five billion new window-mounted air conditioners by 2050 that will add even more to the global warming caused by increasing atmospheric carbon. By an examination of paleoclimatology for the past 420,000 years, it is demonstrable that reducing the concentration of this single most prolific heat-trapping gas by geoengineering back to pre-industrial levels of less than 300 ppm can actually give humankind a collective control over the world’s rapidly rising average global temperature and once more, a temperate climate to live in

Outcomes following laminoplasty or laminectomy and fusion in patients with myelopathy caused by ossification of the posterior longitudinal ligament: A systematic review

Study Design Systematic review. Objective To compare laminoplasty versus laminectomy and fusion in patients with cervical myelopathy caused by OPLL. Methods A systematic review was conducted using PubMed/Medline, Cochrane database, and Google scholar of articles. Only comparative studies in humans were included. Studies involving cervical trauma/fracture, infection, and tumor were excluded. Results Of 157 citations initially analyzed, 4 studies ultimately met our inclusion criteria: one class of evidence (CoE) II prospective cohort study and three CoE III retrospective cohort studies. The prospective cohort study found no significant difference between laminoplasty and laminectomy and fusion in the recovery rate from myelopathy. One CoE III retrospective cohort study reported a significantly higher recovery rate following laminoplasty. Another CoE III retrospective cohort study reported a significantly higher recovery rate in the laminectomy and fusion group. One CoE II prospective cohort study and one CoE III retrospective cohort study found no significant difference in pain improvement between patients treated with laminoplasty versus patients treated with laminectomy and fusion. All four studies reported a higher incidence of C5 palsy following laminectomy and fusion than laminoplasty. One CoE II prospective cohort and one CoE III retrospective cohort reported that there was no significant difference in axial neck pain between the two procedures. One CoE III retrospective cohort study suggested that there was no significant difference between groups in OPLL progression. Conclusion Data from four comparative studies was not sufficient to support the superiority of laminoplasty or laminectomy and fusion in treating cervical myelopathy caused by OPLL

Energy dependence on fractional charge for strongly interacting subsystems

The energies of a pair of strongly-interacting subsystems with arbitrary noninteger charges are examined from closed and open system perspectives. An ensemble representation of the charge dependence is derived, valid at all interaction strengths. Transforming from resonance-state ionicity to ensemble charge dependence imposes physical constraints on the occupation numbers in the strong-interaction limit. For open systems, the chemical potential is evaluated using microscopic and thermodynamic models, leading to a novel correlation between ground-state charge and an electronic temperature.Comment: 4 pages, 3 figs.; as accepted (Phys. Rev. Lett.