Podcasts about debye

Technology which harnesses lightning's nitrogen-fixing properties could revolutionise fertiliser production and supply, cut carbon emissions and support soil health. The Agri-Tech Centres are working with innovative start-up Debye Ltd. to trial its ground-breaking system, which simulates lightning's ability to capture nitrogen in the form of nitrates when it strikes water. Innovative Lightning-based fertiliser tech Debye envisage modular and containerised systems sited on farms or hubs, giving farmers on-the-spot or local supply of nitrate-based fertiliser using only air, water and electricity. The 18-month feasibility R&D project is taking place on lettuce crops in Agri-Tech Centre CHAP's vertical farming facility at Stockbridge, with fellow Centre Agri-EPI providing project management and life-cycle analysis, measuring the product's environmental and economical sustainability at each stage of its development. The objective is to develop a one-kilowatt proof-of-concept prototype, to quantify and compare crop yields and post-harvest properties for standard nitrogen fertiliser and fertiliser produced by Debye Ltd.'s machine and to determine its commercial viability. If the trial is successful, Debye could undertake small-scale pilot projects on a farm setting within three years, subject to funding. The project is funded by Innovate UK and the Biotechnology and Biological Sciences Research Council's Novel low-emission food production systems: Feasibility studies competition. The Agri-Tech Centres help innovative start-ups throughout their journey; securing funding, providing access to research facilities to test, demonstrate and validate new ideas to overcome the agri-industry's critical challenges, such as climate change and environmental sustainability. Burak Karadag, who developed the technology, was originally a space engineer, working on satellite propulsion, when he became interested in the properties of lightning and realised that he would like to see how he could apply space technology to grand challenges on earth. Dr. Burak Karadag, chief technical officer, Debye Ltd said: "Fertiliser is critical to global food security, but current production methods cause environmental harm and are subject to market disruption. "Our technology harnesses nature's own elegant solution: lightning strikes water with such energy that it breaks apart atmospheric nitrogen molecules, creating nitrogen dioxide, which is soluble in water and readily absorbed by plants. Our technology replicates these principles using only air, water and electricity. "Farmers rely mostly on ammonia-based fertiliser, whose economic model relies on mid- to large-scale production using natural gas and with well-documented negative effects on air, soil and water quality. Manufacturers are trying to move to green hydrogen reduce the fertiliser's carbon footprint, but local, renewably powered direct nitrogen capture technology could make it a near zero-emission process, locally and securely available and with far better soil health outcomes. "Today's synthetic fertiliser production accounts for five per cent of global greenhouse gas emissions, equivalent to half the total emissions produced by the EU27 in 2021. Just imagine if we could remove those emissions! Being a rocket scientist was undeniably exciting, but I was so motivated by the challenge of tackling climate change and enhancing food security through innovation that I was glad to make the career shift to agriculture." Dr. Harry Langford, Innovation Network Lead at CHAP, said: "Fertilisers are critical to secure food production, but economic and environmental concerns are driving a renewed focus on both diversification in practice, towards alternative fertiliser types, and technological innovation, to enhance production and application efficiency. The Agri-Tech Centres are delighted to be working with Debye Ltd. to test the feasibility of this exciting technology and help to determine its value proposition....

Lecture 2 in a series of 21 lectures on solid state physics, delivered by Professor Steven H. Simon in early 2014.

Enjoy this rebroadcasting of Zoe and Friends' Exclusive Interview with Debye Swilley and keep posted for a follow-up interview! This amazing woman has served in ministry for over 22 years as a CFO and Executive Administrator at Church In The Now in Conyers, Georgia. She has been a public speaker for over 20 years in the pulpit, conferences, and in civic events. Debye Swilley (Deb Swill) is now available as a Katapult Coach and Speaker! Visit http://katapultent.com/coaches to hire Debye as a coach or contact us at http://katapultent.com/contact to book her as a speaker!

Complex plasmas consist of neutrals, ions, electrons and additional micrometer-sized grains. Fluxes of plasma particles onto the grain surface charge it, and the microparticles interact with each other. When the particles are illuminated, e.g., with a laser, recording the scattered light allows to perform fully resolved kinetic studies at all relevant frequencies, e.g., the Einstein frequency, Debye frequency, and plasma frequency. In this thesis, dynamical effects in fluid complex plasmas are investigated using the PK-3 Plus setup, consisting of a radio-frequency plasma chamber, on the International Space Station (ISS), during a parabolic flight, and on the ground. The objective is the study of dynamical phenomena on the particle level, e.g., to determine when "corpuscular" effects become important and when fluid dynamics provides an accurate description. "Periodgrams" are used to examine the global dynamic structures. Velocities and forces acting on individual particles were analyzed by studying the particle motion. In the ground laboratory, self-excited highly resolved wave structures were analyzed. Thermophoresis was used to vary the extent to which the particles were pushed into the sheath regions of the chamber. The self-excitation of the waves is due to the free energy in plasma ions, which stream fast relative to the microparticles, especially in the sheath region. This excitation mechanism also explains the observed pressure dependence of the excitation threshold. Using a simple model of the microparticle dynamics, the grain charge is estimated, which agrees well with that calculated using known theories. Self-excited waves were neither observed when the particles were completely suspended in the center of the chamber by the thermophoretic force nor during dedicated experiments during the microgravity phase of the parabolic flight. Microparticle waves were externally excited in a complex plasma under microgravity conditions on board the ISS by a variable, low frequency modulation voltage. In addition to the vertical slashing at the externally imposed frequency f_mod, waves propagated both in the vertical and horizontal direction. The horizontal oscillation did not depend on f_mod. When f_mod was resonant with the frequency of the horizontal oscillation, the excitation region of the vertically propagating waves started spreading obliquely towards the left part of the cloud. The dispersion relation of the oblique waves was quasi-sound like. Around f_mod = 9 Hz, the wave activity spread over the whole cloud. At higher frequencies, the oblique waves disappeared. The particle dynamics resembled those accompanying the self-excited waves observed in the ground setup. Under similar conditions as for the self-excited waves, a new phenomenon occurring near the surface of the particle cloud was investigated - the formation of microparticle bubbles, blobs, and surface cusps. The behavior of microparticles was similar to that observed in fluid drops and with sedimenting particles, including the breakup mechanism and vortex motion of particles inside the blobs. The forces acting on the microparticles are analyzed and the velocity scaling with pressure is shown to be compatible with a possible flow induced by thermal creep inside the plasma chamber. Various effects indicate the presence of surface tension, such as the formation of cusps with angles like in Taylor cones, the self-confinement of blobs inside the void, and the break-up of bubble lids. Qualitative agreement with the Rayleigh-Taylor instability is demonstrated.

Deriving Planck's law of blackbody radiation. How to use it to tell the temperature of a star. Discussions about stars -- absorption lines and redshifts, and how to get the temperature correct anyway. Student demo of astronomy course software -- very cool. Counting photons is like counting phonons. (Phonons are quantized vibrational modes in solids.) Visual aid: model of a squishy crystal to demonstrate phonons. Debye law of heat capacity due to phonons in solids. Lecture Audio

Molecular machines are at the ultimate limit of miniaturization. Living organisms provide a variety of examples for such molecular machines, but in order to utilize and to control them, they need to be interfaced with the macroscopic world. On the other h and, there are synthetic molecular machines. Some have been interfaced already but usually in high vacuum at very low temperatures, which is clearly not desirable for technical applications. In this thesis, AFM-based single molecule force spectroscopy (S M FS) was utilized to investigate the mechanical change in single synthetic molecules upon environmental changes (external stimuli) in liquid environment at room temperature. The molecules are either from theory or from bulk experiments supposed to be ab le to convert such an external stimulus into mechanical work, which is a prerequisite for molecular motors. Three different types of molecules and various external energy inputs were investigated which led to the realization of a light driven synthetic mo le cular machine: - Polyelectrolytes should, by OSF-theory, change their persistence length (and therefore the overall length at a constant force) with the Debye screening length of the solvent (which is manipulated by the salt concentration). Therefore, t he elasticity of the polyelectrolyte polyvinylamine, which could be covalently attached to the substrate and the AFM tip, was investigated in dependence on the salt concentration. It was found that the dependence of persistence length on salt concentr atio n is much smaller than expected from OSF-theory, which made this system less attractive for a molecular machine, but led to new theoretical insights. - The adhesive properties of polyelectrolytes onto charged solid supports in aqueous solution are a subj ect of current research in industry and academia. A manipulation of polymer – substrate adhesion, e. g. at an AFM tip, could lead to a molecular 'grab and release' device. Therefore, the desorption force of single polyvinylamine-molecules from solid suppo rts was investigated. Polyvinylamine was physisorbed to a glass substrate and covalently attached to the cantilever. Then, the charge-charge interaction was manipulated by variation in salt concentration and polymer charge. While this has not led t o a sin gle molecule device yet, it gave new insights into the desorption of polyelectrolytes from charged substrates. The measurements performed here revealed that van der Waals forces and other non-covalent chemical interactions such as hydrogen and coo rdinative bonds can by far outweigh the electrostatic coulomb force (namely at short distances), and are therefore a more promising candidate for the tuning of adhesion forces. - Elastin-based polypeptides have proven various kinds of energy conversion i n cross-linked bulk samples. The mechanism is based on a hydrophobic folding transition, which can be manipulated by temperature, salt, pH, electrochemistry, and/or by the composition (hydrophobicity) of the polymers. The difference between the folded and random state could be detected and investigated here at the level of individual polymer chains and characterized by the force-extension traces of the two polypeptides (GVGVP)nx251 and (GVGIP)nx260. Because of their different hydophobicity their folding t emperatu res lie above and below room temperature, respectively. With the polypeptide (GVGIP)nx260 the folded state was investigated extensively. All observations support the conjecture, that intermolecular aggregation dominates intramolecular aggregatio n. This i s further supported by the finding that neither a change in temperature nor the treatment with sodium dodecyl sulfate or guanidinium hydrochloride could force any of the two polypeptides from the folded to the random state or vice versa within a n experime nt, which in turn would be a prerequisite for a polypeptide based molecular motor. - The most successful approach to building an AFM-interfaced molecular machine was in taking advantage of reversible configurational changes in azobenzene poly mer molecul es upon irradiation with light. Azobenzene can be driven from a shorter 'cis' to a longer 'trans' configuration by illumination with l = 420 nm light and vice versa by l = 365 nm. In order to utilize azobenzene, a setup had to be developed and built, whic h allows for the coupling of light into the AFM experiment. Total internal reflection geometry was necessary to avoid any artifacts due to direct effects of the light on the cantilever. A polypeptide chain with multiple functional azobenzene units was cov alently fixed to both, a gold coated cantilever and a flint glass substrate. In the force-extension traces lengthening as well as shortening of the polyazopeptide was observed even under an applied external force. This is not only a proof of principle for the first single molecule motor interfaced to the macroscopic world, but also generates discussion concerning potential energy landscapes under external force.

A dynamical LEED intensity analysis is reported for Cu(001)−c(2 × 2)-Pb. The adsorbate layer distance from the substrate is determined as 2.29 Å, and the topmost interlayer spacing for the substrate is the same as in bulk Cu, in contrast to a contraction for clean Cu(001). This structural result is, within the accuracy reached, insensitive to changes in the assumed scattering potential models. The r-factors suggest a weak preference for an energy-dependent exchange correlation and a moderate one for adding a localized adsorption part inside the muffin-tin spheres. The sensitivity of spectra and r-factors to changes in the assumed isotropic Debye temperature for Pb suggests that vibrational anisotropy should be taken into account in order to improve the accuracy of the analysis. Calculated spin polarization spectra are very sensitive to the exchange approximation, the localized absorption and the Debye temperature. Together with experimental data, they should be useful in particular for determining the vibrational anisotropy.