Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073–2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127–135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260–1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and atomic number (Z) reconstructions to a significant extent.S.J.L., G.R.M., and A.M.K. acknowledge funding through the DigiCore consortium and the support of a linkage grant (LP150101040) from the Australian Research Council and FEI Company

AVIRIS as a tool for carbonatite exploration: Comparison of SPAM and Mbandmap data analysis methods

Data acquired with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) of the Mountain Pass, San Bernadino County, California, area were analyzed to evaluate the use of narrow-band imaging data for carbonatite exploration. Carbonatites are igneous carbonate-rich rocks that are economically important in part because they are the major source for rare-earth minerals. Because the 224 AVIRIS spectral channels have a nominal spectral resolution of 10 nm, narrow absorption features such as those displayed by the rare-earth elements neodymium (Nd) and samarium (Sm) may be detected. The Mountain Pass region encompasses a well-exposed sequence of sedimentary, metamorphic, and igneous rocks, including an alkalic carbonatite intrusion. The carbonatite was emplaced in Precambrian granitic rocks that are fault bounded by a thick suite of Paleozoic, sedimentary rock, predominantly dolomite. The carbonatite stock, the major source of light rare-earth elements (REE) in the United States, affords the opportunity to test AVIRIS capabilities for detecting REE absorption features. Nd-bearing minerals display narrow, sharp and distinctive spectral features at 580, 740, 800, and 870 nm. Minerals bearing Sm display similarly sharp features near 1090, 1250, 1410, and 1550 nm. The more common REE, lanthanum and cerium, do not display absorption features in the visible/near-infrared region in their natural oxidation states

Tabulation, bibliography, and structure of binary intermetallic compounds. II. Compounds of berylium, magnesium, and calcium

This is a tabulation, bibliography, and structure of binary intermetallic compounds, including those of berylium, magnesium, and calcium. This report is the second in a series. ISC-795 ~ the first in this series~ listed the compounds of lithium, sodium, potassium, and rubidium

Rapid production of therapeutic proteins using plant system

Plant molecular farming is simply defined as the production of proteins therapeutics (PT) in plants, which involves transient gene expression in plants and purification of expressed protein to a great scale for diagnosis, treatment and other applications.  This is therapid,economical, safe and reproducible approach for the production of PTas compared to bacterial and mammalian systems. Protein yield and post-translational modifications are the major roadblocks that can be overcome byhigh expression strategies includes over expression constructs, suitable plant host systems and glycoengineering of proteins. The inherent ability of ideally producing safe, functional protein is the most striking phenomenon recognized by the pharmaceutical industries and developed many therapeutic products within few weeks to meet escalating demands during pandemic/epidemic outbreaks recentl

Detection and classification of Bacteria using Raman Spectroscopy Combined with Multivariate Analysis

Vibrational spectroscopic techniques have advantages over conventional microbiological approaches towards identification & detection of pathogens. Since unique spectral fingerprint is obtained, one can identify very closely related bacteria using such methods. In this study Raman microspectroscopy in combination with chemometric method has been used to classify four strains of E. coli (two pathogenic & two non-pathogenic). Different multivariate approaches such as hierarchical cluster analysis, principal component analysis & linear discriminant analysis were explored to obtain efficient classification of the Raman signals obtained from the four strains of E.coli. It was observed that multivariate analysis was able to classify the bacteria at strain level. Linear discrimination analysis using PC scores (PC-LDA) was found to give very good result with as high as 100% accuracy. This hybrid technique (Raman spectroscopy & multivariate analysis) has tremendous potential to be developed as a tool for bacterial identification.

Covariation Among Vowel Height Effects on Acoustic Measures

Covariation among vowel height effects on vowel intrinsic fundamental frequency (IF0), voice onset time (VOT), and voiceless interval duration (VID) is analyzed to assess the plausibility of a common physiological mechanism underlying variation in these measures. Phrases spoken by 20 young adults, containing words composed of initial voiceless stops or /s/ and high or low vowels, were produced in habitual and voluntarily increased F0 conditions. High vowels were associated with increased IF0 and longer VIDs. VOT and VID exhibited significant covariation with IF0 only for males at habitua

The Anti-social Behaviour, Crime and Policing Act 2014: implications for sex workers and their clients

© 2015 Taylor & Francis. The Anti-social Behaviour, Crime and Policing Act 2014 introduced new powers to deal with behaviour deemed to be ‘anti-social’. In this paper we consider how the new law could be used against sex workers and their clients and the impact this may have. Although the new powers were not intentionally designed to respond to prostitution, we suggest that they will be utilised to tackle it. We argue that the law will be used inconsistently in a way which will go directly against policy which seeks to ‘tackle demand’ and take a less punitive approach to dealing with sex workers. Despite a policy shift to see sex workers more as victims and less as offenders, we draw on existing evidence to demonstrate that the new anti-social behaviour order law will be utilised to exclude street sex workers from public spaces. We claim that a degree of ‘policy re-fraction’ will occur when the new laws are implemented by practitioners

‘It’s better than daytime television’: questioning the socio-spatial impacts of massage parlours on residential communities

It has been shown that street sex work is problematic for some communities, but there is less evidence of the effects of brothels. Emerging research also suggests that impact discourses outlined by residential communities and in regulatory policies should be critiqued, because they are often based on minority community voices, and limited tangible evidence is used to masquerade wider moral viewpoints about the place of sex work. Using a study of residents living in close proximity to brothels in Blackpool, this paper argues that impact is socially and spatially fluid. Impact needs to be evaluated in a more nuanced manner, which is considerate of the heterogeneity of (even one type of) sex work, and the community in question. Brothels in Blackpool had a variety of roles in the everyday socio-spatial fabric; thus also questioning the common assumption that sex work only impacts negatively on residential communities