Evaluating the feasibility of implementing direct analysis in real time - mass spectrometry for the forensic examination of post-blast debris

Improvised explosive devices (IEDs) continue to be a national threat to the safety and security of the public. Research in explosives analysis for intact and post-blast samples continue to be a topic in which practitioners are constantly improving and searching for faster methods and techniques to analyze these sample types. The key role crime laboratories play in analyzing these sample types can have limitations, such as increasing turnaround times and backlogs. This concern additionally plays a role in the safety of the public if an unknown individual has not been discovered. Current analytical instrumentation in which explosives are analyzed includes Gas Chromatography – Mass Spectrometry (GC-MS), Liquid Chromatography – Mass Spectrometry (LC-MS), and Ion Mobility Spectrometry (IMS). Each instrument has benefits in the analytical results obtained. Direct Analysis in Real Time - Mass Spectrometry (DART-MS) has shown a significant promise as an analytical approach that can help remedy the time an explosive sample is analyzed, while additionally providing discriminating analytical results. Previous research has shown that DART-MS is capable of analyzing explosives, including smokeless powder. A limitation currently in the area of smokeless powder analysis with DART-MS is the application of utilizing this method and technology to realistic casework that may be encountered in forensic laboratories. Intact and post-blast explosive samples encountered in forensic laboratories arrive in various states and conditions. For example, the severity of the blast and environmental factors may play a role in the detection of smokeless powder on these sample types. To provide objective information and additional research, studies were conducted with mixture samples of smokeless powder and potential matrices that may be encountered in real world case samples. Faster processing time, in addition to the discrimination of smokeless powder, was the ultimate goal of this research. Due to the complexity of the mass spectra that may be generated from sample mixtures, an extraction technique coupled with DART-MS was investigated. A liquid-liquid extraction (LLE) method and dynamic headspace concentration using Carbopack™ X coated wire mesh were tested for the effectiveness of separating the analytes of interest of smokeless powder from various matrix interferences. Hodgdon Hornady LEVERevolution (HHL) smokeless powder, Pennzoil 10W-40 (P10W40) motor oil, and residue from metal end caps (China SLK brand) and black steel pipe nipples (Schedule 40) were used during the course of the matrix interference study. The method of applying dynamic headspace concentration using Carbopack™ X coated wire mesh and analysis by DART-MS provides an effective alternative to obtaining mass spectral data in a shorter amount of time, compared to techniques currently used in forensic laboratories. Effective separation was not achieved using the various LLE methods tested. Further testing would be required in order to evaluate the feasibility of implementing the technique as a sample preparation approach prior to analysis by DART-MS

Time reversal invariance - a test in free neutron decay

Time reversal invariance violation plays only a small role in the Standard Model, and the existence of a T-violating effect above the predicted level would be an indication of new physics. A sensitive probe of this symmetry in the weak interaction is the measurement of the T-violating ''D''-correlation in the decay of free neutrons. The triple-correlation D{sigma}{sub n}{center_dot}p{sub e} x p{sub v} involves three kinematic variables, the neutron spin, electron momentu, and neutrino (or proton) momentum, and changes sign under time reversal. This experiment detects the decay products of a polarized cold neutron beam with an octagonal array of scintillation and solid-state detectors. Data from first run at NIST's Cold Neutron Research Facility give a D-coefficient of -0.1 {+-} 1.3(stat.) {+-} 0.7(syst) x 10{sup -3}. This measurement has the greatest bearing on extensions to the Standard model that incorporate leptoquarks, although exotic fermion and lift-right symmetric models also allow a D as large as the present limit

The Greatest Relationship

My story is about my journey of learning to enjoy my own company and love myself

An application of the Mossbauer effect to the study of some magnetic properties of ilmenite

The investigations described in this thesis clarify and supplement, by means of Mossbauer spectroscopy, the magnetic properties and chemical composition of natural ilmenite and its oxidation products. Natural ilmenite was found by some investigators, using a m.agnetic measurement method, to be weakly ferrimagnetic but was revealed to be in a paramagnetic state by others using Mossbauer spectroscopy. There was an uncertainty about the nature of the magnetic properties of an ilmenite sample which had been partially oxidised by heat treatment. The types of compounds existing in natural ilmenite and its oxidation products were not clearly determined

Faculty perceptions regarding the infusion of global perspectives into the College of Agriculture and Life Sciences curriculum: A comparative study

A comparative study was conducted to explore faculty perceptions regarding the infusion of global perspectives into the College of Agriculture and Life Sciences (CALS) curriculum at Iowa State University. King (1991) provided the original base for the study which enabled a comparison with data recently collected. This study may fill a void in the literature published in the context of the CALS faculty members’ perceptions in infusing a global perspective into the curriculum over the periods covered. The gap between the original and current study may reveal a possible new mindset and trend in the perceived benefits and barriers of infusing global perspectives into the curriculum. An online survey using Qualtrics was used to collect data. The survey material was comprised of five parts: perception statements, critical content/topics, activities used to add global perspectives, opinions on the infusion of global perspectives and demographic information. Descriptive and inferential analyses were used to compare the data collected. Significant differences were found in the demographic and occupational information of gender, age and primary workload. There were also significant differences in students’ activities used to add international perspectives, comparative reasons for the departmental curriculum problems, and activities for curriculum improvement. Four of the 16 identified perception statements and 10 of the 48 identified critical content/topics were found to be statistically different in the two years that were compared. ANOVA results for both perception statements and the critical content/topics were significantly different on the identified races in the 1991 study but not on the 2016 study. Even after 25 years, the perceptions of CALS faculty members regarding the infusion of global perspectives has remained the same on majority of the statements for internationalization and perceived critical topics to be taught from a global perspectives

The impact of epistemology on learning: A case study from introductory physics

We discuss a case study of the influence of epistemology on learning for a student in an introductory college physics course. An analysis of videotaped class work, written work, and interviews indicates that many of the student's difficulties were epistemological in nature. Our primary goal is to show instructors and curriculum developers that a student's epistemological stance - her ideas about knowledge and learning - can have a direct, causal influence on her learning of physics. This influence exists even when research-based curriculum materials provide implicit epistemological support. For this reason, curriculum materials and teaching techniques could become more effective by explicitly attending to students' epistemologies.Comment: 11 pages, 1 figure, accepted to the American Journal of Physic

Deeply subrecoil two-dimensional Raman cooling

We report the implementation of a two-dimensional Raman cooling scheme using sequential excitations along the orthogonal axes. Using square pulses, we have cooled a cloud of ultracold Cesium atoms down to an RMS velocity spread of 0.39(5) recoil velocity, corresponding to an effective temperature of 30 nK (0.15 T_rec). This technique can be useful to improve cold atom atomic clocks, and is particularly relevant for clocks in microgravity.Comment: 8 pages, 6 figures, submitted to Phys. Rev.

Psychosexuelle Disposition und weibliche Lebensgeschichte

Grundlage des Beitrags ist die Erkenntnis, daß die Veränderungsmöglichkeiten menschlicher Objektwahl und Sexualbedürfnisse größer sind als dies gemeinhin angenommen wird, d.h. daß die heterosexuelle oder homosexuelle Disposition letztlich doch veränderbar ist. Davon ausgehend wird die Tragfähigkeit des psychoanalytischen Dispositionsbegriffs im Hinblick auf sogenannte heterosexuell disponierte Frauen in Frage gestellt und ein an der weiblichen Lebensgeschichte orientiertes Erklärungsmodell für psychosexuellen Identitätswandel entwickelt. Anhand der Spezifik der psychosexuellen Entwicklungsprozesse von Frauen im lebensgeschichtlichen Kontext wird die These erklärt, daß die heterosexuelle Disposition von Frauen nicht in jedem Fall eine lebenslange Determination darstellt, sondern unter bestimmten sozialen Bedingungen in ausschließlich homosexuelle Bedürfnisse und Beziehungen umschlägt, also ein psychosexueller Identitätswandel erfolgt. Für die Erklärung wird im Unterschied zum statischen psychoanalytischen Phasenmodell von der Dynamik der gesamten weiblichen Lebensgeschichte ausgegangen und diese als Versuch der Selbstfindung oder als psychosozialer Prozeß der Subjektwerdung verstanden. Zusammenfassen wird behauptet, daß die bisher noch seltenen Beziehungen zwischen Frauen weit weniger eine Frage der psychosexuellen Disposition sind als eine Frage der gesellschaftlichen Stützung von heterosexuellen Beziehungen und der gesellschaftlichen Diskriminierung von Frauenbeziehungen. (RW

The D coefficient in neutron beta decay in effective field theory

In this paper we explore the time-reversal-odd triple-correlation coefficient in neutron beta decay, the so-called "D coefficient", using heavy-baryon effective field theory with photon degrees of freedom. We find that this framework allows us to reproduce the known results for the contribution which comes from final-state interactions, and also to discuss higher-order corrections. In particular we are able to show that in the heavy-baryon limit all electromagnetic contributions vanish. By calculating the leading correction to the known result, we give a final expression which is accurate to better than 1%. Hence we extend downwards the range over which the D coefficient could be used to explore time-violation from new physics.Comment: 12c pages, 3 eps figures Version accepted for publication in Physics Letters B; minor changes of wordin

Comparison of two experiments on radiative neutron decay

Over 10 years ago we proposed an experiment on measuring the characteristics of radiative neutron decay in papers [1, 2]. At the same time we had published the theoretical spectrum of radiative gamma quanta, calculated within the framework of the electroweak interactions, on the basis of which we proposed the methodology for the future experiment [3,4]. However, because we were denied beam time on the intensive cold neutron beam at ILL (Grenoble, France) for a number of years, we could only conduct the experiment in 2005 on the newly opened FRMII reactor of Technical University of Muenchen. The main result of this experiment was the discovery of radiative neutron decay and the measurement of its relative intensity B.R.= (3.2+-1.6)10-3 with C.L.=99.7% for radiative gamma quanta with energy over 35 kev [5,6]. Over a year after our first announcement about the results of the conducted experiment, "Nature" [7] published a letter asserting that its authors have also measured the branching ratio of radiative neutron decay B.R.= (3.13+-0.34)10-3 with C.L.=68% and gamma quanta energy from 15 to 340 kev. This article aims to compare these two experiments. It is shown that the use of strong magnetic fields in the NIST (Washington, USA) experiment methodology not only prevents any exact measurement of the branching ratio and identification of radiative neutron decay events, but also makes registration of ordinary neutron decay events impossible.Comment: contribution on conference ISINN-1