Coarsening Investigations of Precipitates in PM Tool Steel Grades: an Effect of Nitrogen

We present experimental and theoretical comparisons of the coarsening rate for the MX (X?=?C, N or C?+?N) precipitate in five different tool steel grades produced by Powder Metallurgy (PM). The alloys contain different amounts of nitrogen and carbon; ranging from high carbon/low nitrogen to high nitrogen/low carbon. Common for the grades is a high amount of precipitate forming alloying elements resulting in a high fraction of hard phase. Experimentally we have found out that the nitrogen rich precipitates coarsen slower, both for higher and lower carbon content, than the carbon rich precipitates. Coarsening simulations are performed utilizing the DICTRA software and an agreement between calculations and measurements can be concluded.     

Object loss, mourning, and adjustment to disability.

This article explores the relationship between concepts of object loss and mourning and the loss of a bodily part or psychological or physical function in a rehabilitation context. The psychoanalytic literature on object loss and the mourning process is reviewed and related to existing literature on the adjustment-to-disability process. Similarities and differences between the classical mourning process and the adjustment-to-disability process are discussed, and suggestions are offered for using psychoanalytic strategies to facilitate adjustment to disability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of Undergraduate Students’ Professional Skills

The development of engineering students’ professional skills has gained considerable national attention from Accreditation Board for Engineering and Technology, the National Academy of Engineering, ASCE, and other constituents. There is little debate that these professional skills are necessary. Engineering programs have tried many approaches to develop these skills in the undergraduate programs. Colorado State University (CSU) has developed a new approach modeled on the type of professional development that occurs in the professional environment. This new Professional Learning Institute (PLI) provides students with a broad array of workshops, presentations, and experiential opportunities addressing the areas of cross cultural communication and teamwork, innovation, leadership, ethics, and public service. This program introduces students to the concept of professional development through required extracurricular activities, includes minimum requirements along with requirements to earn certificates in specialty areas for motivated students. The majority of offerings in the PLI are presented by leaders from the engineering profession who have teamed with CSU to provide high quality programs for our students.     

Digital passband filtering of megabaud transmitted data stream

A digital filter architecture for spectral shaping of a transmitted QAM signal is described. The technique requires that a binary representation for a finite sequence of multilevel symbols be interpreted as an address to memory that stores a pre-emphasised output that uniquely defines the desired transmitted transfer function. Design of a 6-34 Mbaud 16-QAM filter is illustrated.<>     

Zur Chemie des Hopfens

Ohne ZusammenfassungMitteilung aus dem Gärungschemischen Laboratorium der Kgl. Technischen Hochschule in München. (Vorstand: Prof. Dr. C. Lintner.)     

The application of first order mixing statistics to the variation of the diffusivity of carbon in austenite

An expression for the variation with composition of the diffusivity of the solute atoms in interstitial solid solutions is derived. The diffusion model is based on the application of the absolute reaction rate theory to a solution whose mixing statistics are described by first order pairwise interactions. The theoretical expression is compared with experimental data for carbon in austenite and excellent agreement is found using a solute-solute binding energy identical to that found from the equilibrium thermodynamics of the system.     

Design of multiple edge blinders for pyramidal horn reflector antennas

The design of multiple edge blinders for pyramidal horn reflector antennas is discussed. The blinders eliminate high sidelobes in the azimuthal plane near90degfor horizontal polarization at 4, 6, and 11 GHz. The successful design of multiple edge blinders for simultaneous operation in each of the three common carrier bands depends upon the suppression of an off-axis major lobe at 4 GHz and grating lobes which typically appear at 6 and 11 GHz. Using the blinder array factor and element pattern, it is shown that these lobes can be suppressed by properly choosing the blinder tilt anglebeta_{c}, the inclination of an individual blinder edgedelta, and an adequate number of edgesN.     

Degradation of cyanide in agroindustrial or industrial wastewater in an acidification reactor or in a single-step methane reactor by bacteria enriched from soil and peels of cassava

During cassava starch production, large amounts of cyanoglycosides were released and hydrolysed by plant-borne enzymes, leading to cyanide concentrations in the wastewater as high as 200 mg/l. For anaerobic degradation of the cyanide during pre-acidification or single-step methane fermentation, anaerobic cultures were enriched from soil residues of cassava roots and sewage sludge. In a pre-acidification reactor this culture was able to remove up to 4 g potassium cyanide/l of wastewater at a hydraulic retention time (tHR) of 4 days, equivalent to a maximal cyanide space loading of 400 mg CN- 1(-1) day-1. The residual cyanide concentration was 0.2-0.5 mg/l. Concentrated cell suspensions of the mixed culture formed ammonia and formate in almost equimolar amounts from cyanide. Little formamide was generated by chemical decay. A concentration of up to 100 mmol ammonia/l had no inhibitory effect on cyanide degradation. The optimal pH for cyanide degradation was 6-7.5, the optimal temperature 25-37 degrees C. At a pH of 5 or lower, cyanide accumulated in the reactor and pre-acidification failed. The minimal tHR for continuous cyanide removal was 1.5 days. The enriched mixed culture was also able to degrade cyanide in purely mineralic wastewater from metal deburring, either in a pre-acidification reactor with a two-step process or in a one-step methanogenic reactor. It was necessary to supplement the wastewater with a carbon source (e.g. starch) to keep the population active enough to cope with any possible inhibiting effect of cyanide.