X-ray fluorescence spectroscopic analysis of coal ash

Several coal ashes and prepared mixtures were analyzed by x-ray fluorescence spectroscopy. Various techniques were studied to determine the most reliable procedure for quantitatively estimating, from fluorescent peak intensities, the concentrations of seven major oxides typically present in the ash. These ashes were analyzed with only minimal sample preparation. In order to determine the self-consistency of the procedure, several mixtures of known composition were prepared containing the major elements present in an ash. Because of inter-element absorption and enhancement effects, several computational techniques were used to calculate composition from spectrum peak intensities. The method that yielded the most accurate estimates of the mixtures was an empirical form devised by Criss and Burkes. Comparison of the estimated coal ash compositions by this procedure did not agree with results obtained by atomic absorption analysis. However, it is believed that this is not because of the x-ray fluorescence procedure applied; inconsistent ash sampling and preparation and improper standards are the probable causes

Blending Learning: The Evolution of Online and Face-to-Face Education from 20082015

In 2008, iNACOL produced a series of papers documenting promising practices identified throughout the field of K–12 online learning. Since then, we have witnessed a tremendous acceleration of transformative policy and practice driving personalized learning in the K–12 education space. State, district, school, and classroom leaders recognize that the ultimate potential for blended and online learning lies in the opportunity to transform the education system and enable higher levels of learning through competency-based approaches.iNACOL's core work adds significant value to the field by providing a powerful practitioner voice in policy advocacy, communications, and in the creation of resources and best practices to enable transformational change in K–12 education.We worked with leaders throughout the field to update these resources for a new generation of pioneers working towards the creation of student-centered learning environments.This refreshed series, Promising Practices in Blended and Online Learning, explores some of the approaches developed by practitioners and policymakers in response to key issues in K–12 education, including:Blended Learning: The Evolution of Online and Face-to-Face Education from 2008-2015;Using Blended and Online Learning for Credit Recovery and At-Risk Students;Oversight and Management of Blended and Online Programs: Ensuring Quality and Accountability; andFunding and Legislation for Blended and Online Education.Personalized learning environments provide the very best educational opportunities and personalized pathways for all students, with highly qualified teachers delivering world-class instruction using innovative digital resources and content. Through this series of white papers, we are pleased to share the promising practices in K–12 blended, online, and competency education transforming teaching and learning today

On the Indeterministic Nature of Star Formation on the Cloud Scale

Molecular clouds are turbulent structures whose star formation efficiency (SFE) is strongly affected by internal stellar feedback processes. In this paper we determine how sensitive the SFE of molecular clouds is to randomised inputs in the star formation feedback loop, and to what extent relationships between emergent cloud properties and the SFE can be recovered. We introduce the yule suite of 26 radiative magnetohydrodynamic (RMHD) simulations of a 10,000 solar mass cloud similar to those in the solar neighbourhood. We use the same initial global properties in every simulation but vary the initial mass function (IMF) sampling and initial cloud velocity structure. The final SFE lies between 6 and 23 percent when either of these parameters are changed. We use Bayesian mixed-effects models to uncover trends in the SFE. The number of photons emitted early in the cluster's life and the length of the cloud provide are the strongest predictors of the SFE. The HII regions evolve following an analytic model of expansion into a roughly isothermal density field. The more efficient feedback is at evaporating the cloud, the less the star cluster is dispersed. We argue that this is because if the gas is evaporated slowly, the stars are dragged outwards towards surviving gas clumps due to the gravitational attraction between the stars and gas. While star formation and feedback efficiencies are dependent on nonlinear processes, statistical models describing cloud-scale processes can be constructed.Comment: 24 pages, 16 figures, 6 tables. Accepted to MNRAS, version updated with published titl

Effect of Developer Temperature on Photoresist Contrast in Grayscale Lithography

SPR 220-3 photoresist was spin-coated onto a silicon wafer, exposed using a Heidelberg DWL66+ laserwriter at different laser powers, and developed at different temperatures. The effect of developer temperature on photoresist contrast was examined. Results show that increasing developer temperature decreased photoresist contrast and increased required dose

How to cleave wafers: LatticeGear protocol

We report on the process protocol to cleave wafers using LatticeGear cleaving and scribing tools sets

Manheim Auctions

Manheim Auctions, the world\u27s largest auction house, recently developed Manheim Online (MOL) to sell program cars (cars that have been leased or hired) in response to the Japanese company AUCNET\u27s efforts to penetrate the US car auction business. This Internet-based electronic sales system has tremendous potential to change the car auction business. There are over 80,000 used car dealers in the US and Manheim auctions some 6 million cars each year. Trying to leverage its knowledge of the automobile market to provide services to its customers, Manheim developed two other products, Manheim Market Report and AutoConnect. It is also expanding its auction business in Europe. Manheim wants to continue to add value to Manheim Online as a way of discouraging competition and of extending sales through the Internet without cannibalizing Manheim\u27s core business

Correction of pattern size deviations in the fabrication of photomasks made with a laser direct-writer

When using Heidelberg DWL66+ laser writer to fabricate the photomask, the pattern feature dimensions may have deviations. These deviations can be caused by the lithography process and the undercut in the metal etch process. The same deviation value of 0.8µm was found to appear in all the patterns independent of the pattern original size and local pattern density. To overcome this universal deviation, a universal bias is suggested to be applied to the original patterns during the data preparation for the lithography process. In order to ensure this pre-exposure bias method can work, both the laser direct-write exposure conditions (laser power, filters, focus parameters) and the metal etch time should be kept consistent

Optimization of Bilayer Lift-Off Process to Enable the Gap Size of 1μm Using LOR 3A and S1813

Bilayer lift-off process for 1μm feature size is demonstrated using LOR 3A and S1813 photoresist. The thickness of photoresists was fixed, whereas development time is varied. The process was further investigated by measuring the undercut depth and undercut rate by scanning electron microscopy. An optimized and reproducible recipe is provided

Biorelevant drug release of Metformin dosage forms using complementary in vitro tools

Drug release from immediate release (IR) and extended release (ER) metformin products was investigated using the Dow Chemical Company’s FloVitroTM biorelevant dissolution instrument. This was complemented by using the Sirius SDi2 (Surface Dissolution Imaging) platform to investigate mechanistic differences accounting for drug release. Level A IVIVC was demonstrated for metformin IR dosage forms, using FloVitroTM, whilst ER tablets demonstrated lower Cmax and Tmax using the same method. The SDi2 showed disintegration as the main release mechanism for IR tablets, whilst swelling and drug diffusion was observed for ER tablets. FloVitroTM and SDi2 technologies can be used to compare behaviour of formulations during dosage form selectio

Press scrums: some preliminary observations

Press scrums: some preliminary observation