Influence of Residual Elements on Mechanical Properties of Two Carbon Steel Grades

Experiments were carried out to study the influence of residual elements on microstructure and mechanical properties of two carbon steel grades (i.e. 0.04% C and 0.20% C). The effect of residuals on the microstructure of the carbon steels was mainly to decrease ferrite grain sizes. The effect of residuals on tensile properties was mainly to increase yield and tensile strengths and to slightly decrease ductility, which reflected a combination of solid solution hardening by residuals and grain refinement. The 40 J notch toughness transition temperature (TT) was determined by fitting Charpy absorbed energies to a hyperbolic function and by finding the temperature corresponding to 40 J in the fitted curve; a statistical analysis was performed to ensure the repeatability of TTs defined by this procedure. After the step‐cooling heat treatment to maximize segregation, the 40 J TT of a 0.04% C steel with high Mn and Si contents increased by 28K and the 40 J TT of 0.20 % C steels with the highest residual level (0.085% Sn, 0.4% Cu and 0.4% Ni) increased by 24K, indicating that the upward shift of TT is small even for high levels of residuals. Grain boundary segregation was semi‐quantitatively analysed by Auger electron spectroscopy. Small amounts of Sn segregation were observed, most notably in the low‐C grade.     

Numerical verification of stress intensity factor solution for clamped single edge notched tension (SENT) specimens

Stress intensity factor solutions for clamped single edge notched tension (SENT) specimens, including a closed‐form function recently proposed by Zhu along with a function by CanmetMATERIALS referenced in the British Standard BS 8571, have been assessed. Solutions for an SENT specimen with a daylight‐to‐width ratio of 10 have been compared with new finite element results generated in this work to assess their accuracies. The results of this study show that the polynomial proposed by Zhu differs by no more than 0.23% compared with the numerical results over the range of 0.2 ≤a/W ≤ 0.7. The CANMET function differs by no more than 0.69% over the same range.     

An adaptive management approach for implementing multi-jurisdictional response to grass carp in Lake Erie

The Great Lakes are influenced by established aquatic invasive species (AIS) and the threat of new invaders persists. Grass carp, one of four species commonly referred to as Asian carp, are considered invasive because of their ability to adversely modify aquatic habitat through consumption of aquatic macrophytes. Grass carp have been infrequently detected in the Great Lakes since the mid-1980s. More frequent reports of grass carp captures from commercial fishermen in the early 2010’s elevated the concern of the potential risk of colonization in Lake Erie. This paper provides a case study detailing the development and implementation of a multi-jurisdictional response strategy for grass carp in Lake Erie. To respond to threats of grass carp in Lake Erie, Michigan and Ohio Departments of Natural Resources led targeted responses using a collaborative multi-jurisdictional approach, while simultaneously investing in reducing critical life-history uncertainties to refine strategies in an adaptive and science-based manner. Efforts to address uncertainties about grass carp life history documented spawning in two Lake Erie tributaries. Building on these early responses, the binational Lake Erie Committee developed a five-year adaptive response framework to guide response actions. The collaborative response efforts resulted in the capture and removal of 184 fertile grass carp since 2014, and efforts are ongoing to increase effectiveness of strategies to achieve desired population reduction. Coordinated grass carp response actions under the five-year strategy will continue using adaptive management principles with outcomes providing useful insights for adapting existing response frameworks and more broadly for AIS responses implemented elsewhere.     

Chemical Potential of Vacancies in Metal Crystals

In this paper, a concept, the chemical potential of vacancies in metal crystals, has been derived from the partial mole free energy of vacancies based on a model of an atom-vacancy binary solution.For a pure metal crystal containing the mole concentration of vacancies, Cv and it's value in thermal equilibrium,C0, at temperature T the chemical potential can be expressed respectively as: μ v(Cv)=RT[1+1n(C√Co)]and μ v (Co)=RT The second term in μ v(Cv) is the chemical potential of the vacancies referred to the standardstate concentration given by J. P. Hirth [1] and first term is the standard-state one presented in this paper.     

Bit-error rate for free-space adaptive optics laser communications

An analysis of adaptive optics compensation for atmospheric-turbulence-induced scintillation is presented with the figure of merit being the laser communications bit-error rate. The formulation covers weak, moderate, and strong turbulence; on-off keying; and amplitude-shift keying, over horizontal propagation paths or on a ground-to-space uplink or downlink. The theory shows that under some circumstances the bit-error rate can be improved by a few orders of magnitude with the addition of adaptive optics to compensate for the scintillation. Low-order compensation (less than 40 Zernike modes) appears to be feasible as well as beneficial for reducing the bit-error rate and increasing the throughput of the communication link.     

Exploring the importance of the relative solubility of matrix and analyte in MALDI sample preparation using HPLC

New insight into the role of solubility in the sample preparation process for MALDI MS is reported. Reversed-phase gradient HPLC conditions were developed that enable the analysis of a broad range of analyte polarities with a single method. This HPLC method was used to establish a relative polarity scale for a series of 15 MALDI matrix materials, a set of example peptides, and a series of model polymer materials with a broad range of polarity. Examples of each polymer type within the range of 6000-10,000 were analyzed with six matrixes that cover a broad range of polarity using MALDI TOFMS. With regard to polymer signal-to-noise ratio, the matrix and polymer combinations that had a close match of HPLC retention time produced the best MALDI spectra. Conversely, the matrix and polymer combinations that have a large difference in HPLC retention time produced poor MALDI spectra. The results suggest that there is a relationship between polarity (solubility) and effective MALDI sample preparation. The relative HPLC retention time of an unknown polymer can serve as a starting point for predicting the matrix (or range of matrixes) that would be most effective.     

Human cerebral neoplasms studied using MR spectroscopy: a review

Of primary central nervous system tumors treated each year, the majority are glioma, followed by meningioma and then pituitary adenoma. While the use of magnetic resonance (MR) and computed tomographic imaging is well established in the diagnosis and management of such tumors, these techniques have a limited role in determining the metabolic state, either prior to or following therapy. Multinuclear MR spectroscopy, on the other hand, provides information on tumor metabolism and the effect of therapy on tumor viability. This paper reviews MR spectroscopic studies performed on patients with central nervous system tumors and discusses the impact that such studies have had on tumor diagnosis and management.     

A set of BASIC programs to evaluate relationships among protein sequences by optimum alignment and distance matrix analysis.

These six programs evaluate relationships among a number (> 2) of protein (or DNA) sequences. Program 1 automatically computes optimum alignments and total distances for all pairwise sequence combinations over any user desired range of the two gap penalties. Programs 2, 3 and 4 generate a square, symmetrical distance matrix, which can be exported for cluster analysis, or further analysed with programs 5 and 6 to give specific distances between sequences and extract sequence relationships. Data and results are exchanged among these programs, which are written in BASIC and compiled to run on Macintosh (68020/030/040) type machines with coprocessor and at least one MB of RAM. BASIC graphics commands or those for the Macintosh interface are avoided to facilitate use on other machines. Two groups of sequences are used to demonstrate (a) alignment, inter sequence distance calculation and dendrogram generation and (b) specific distance calculation and its usage in detecting sub groups of related sequences in dendrograms.