Physical Sciences and Mathematics Commons^™

Kinematic Effects In Large Transport Aircraft, Shem Malmquist, Dennis Vincenzi, Dahai Liu

Dahai Liu

The control of an aircraft relies on sensory feedback. It follows that any aspect that could create a situation where that feedback is faulty can lead to unintended outcomes. The size of very large jet aircraft can result in kinematic effects that impact the perceptions of the flight crew. Due to the large amount of inertia involved, coupled with aerodynamic factors, when the aircraft pitch (θ) is initially changed, the short term actual motion of the aircraft, as viewed from the center of gravity, remains relatively unchanged. As a consequence of aircraft design, this results in the flight deck changing …

Trends In The Prevalence And Mortality Of Cognitive Impairment In The United States: Is There Evidence Of A Compression Of Cognitive Morbidity, Kenneth Langa, Eric Larson, Jason Karlawish, David Cutler, Mohammed Kabeto, Scott Kim, Allison Rosen

Jason Karlawish

BACKGROUND: Recent medical, demographic, and social trends might have had an important impact on the cognitive health of older adults. To assess the impact of these multiple trends, we compared the prevalence and 2-year mortality of cognitive impairment (CI) consistent with dementia in the United States in 1993 to 1995 and 2002 to 2004. METHODS: We used data from the Health and Retirement Study (HRS), a nationally representative population-based longitudinal survey of U.S. adults. Individuals aged 70 years or older from the 1993 (N = 7,406) and 2002 (N = 7,104) waves of the HRS were included. CI was determined …

A New Family Of Nonexchangeable Copulas For Positive Dependence, Roy Cerqueti, Claudio Lupi

Claudio Lupi

Plasma Focus Device As A Breeder Of 14.66 Mev Protons To Produce Short-Lived Radioisotopes, A. Zaeem, S.M. Kaia, M. Sedaghatizadeh, Ahmad Talaei

Ahmad Talaei

In plasma focus devices filled deuterium gas with low pressure admixture gas, 3He, the deuterium creates high energy protons of 14.66 MeV through the 3He(d, p) 4He(Q = 18.35 MeV) fusion reaction. This reaction takes place due to the thermal and non-thermal (beam-target) mechanisms. The proton yield production for deuterium filling gas is determined by using the beam-target character of the pinched plasma and moving boiler model. If we use a low pressure admixture gas like 11B, these high energy protons in turn, could generate short-lived radioisotopes like 11C (used in positron emission tomography) via the …

Influence Of Admixture Gas On The Enhancement Of Neutron Production In Plasma Focus Devices, Ahmad Talaei, S.M. Kaia

Ahmad Talaei

In this article, considering the most important interactions between the ionized admixture particles and the working plasma ones, we have analyzed the effect of added gas on the current and confinement time of the pinched plasma in plasma focus devices. Moreover, we demonstrate how heating and cooling the pinched plasma can be controlled by the increase and decrease on the percentage of the added particles and by this way the rise in the rate of D–D nuclear reactions is calculated.

Theoretical Study Of The Endogenous Production Of N-13 In 115 Kj Plasma Focus Device Using Methane Gas, Saeedeh Haghani, A. Sadighzadeh, Ahmad Talaei, A. Zeem, S.M. Kiai, A. Heydarnia, V. Damideh

Ahmad Talaei

Mather type plasma focus device with the bank energy of 115 kJ (40 kV, 144μF) was studied for induced activity of N-13; a short-lived radioisotope β+ emitter with 511 keV of gamma rays and has a half-life of t1/2 = 9.93 min through 12C (d, n)13N nuclear reaction. N-13 radioisotope is used in Positron Emission Tomography (PET) for imaging and treatment. In this paper endogenous production of 13N is considered. It is shown by adding 3–4 % CH4 to the chamber, the induced activity of N-13 has increased about 4 %. Our study is representative of producing 106 − 109 …

Study The Output Characteristics Of A 90 Kj Filippove-Type Plasma Focus, S.M. Kiai, Ahmad Talaei, Et Al.

Ahmad Talaei

The output characteristics of a Filippove-Type plasma focus “Dena” (288 μF, 25 kV, 90 kJ) is numerically investigated by considering the voltage, current, current derivative, and maximum current as a function of capacitor bank energy in the constant Argon gas pressure and compared to the experiment. It is shown that increase on the bank energy leads to the increment on the maximum current and decrement on the pinch time.

Effects Of Admixture Gas On The Production Of 18f Radioisotope In Plasma Focus Devices, Ahmad Talaei, S.M. Kaia, A. Zeem

Ahmad Talaei

In this article, the effect of admixture gas on the heating and cooling of pinched plasma directly related to the enhancement or reduction of ¹⁸F production through the ¹⁶O(³He, p)¹⁸F is considered in the plasma focus devices. It is shown that by controlling the velocity of added Oxygen particles mixed with the working helium gas into the plasma focus chamber, one can increase the current and decrease the confinement time (plasma heating) or vice verse (plasma cooling). The highest level of nuclear activities of ¹⁸F was found around 16% of the Oxygen admixture …

Study The Influence Of The Bank Energy On The Dynamical Pinch In Plasma Focus, Ahmad Talaei, S.M. Kaia

Ahmad Talaei

The plasma focus discharge can generate, accelerate and pinch the plasma up to high density and temperature in a pulsed mode manner. Applications aspects of discharge require high efficiency of the fusion products. This situation acquires optimized operational parameters for the proper discharge. In this article, we have studied the plasma parameters and neutron performance dependency on bank energy. First, analytical expressions are derived from the equation of motion for the plasma particles in the radial phase. Then, the related fusion neutrons, both thermal and non-thermal, together with the discharge anisotropy in the low pressure regimes for the ‘Dena’ plasma …

Pinched Plasma Study In A Filippov-Type Plasma Focus “Dena”, Ahmad Talaei, S. Kaia, S. Adlparvar

Ahmad Talaei

A characteristic feature of physical processes occurring in pinched plasma is their tendency to generate thermal and nonthermal emissions. In this case, the roles played by plasma compression dynamics such as pinch formation, pinch disruption, expansion, etc., are predominant. In this paper, first, we present some of the experimental results concerning the thermal and nonthermal neutron emissions. Then, a new approach based on some theoretical assumptions and the experimental data for which the pinched plasma density evolution was studied are introduced. In the new approach, the compression dynamics are divided into two phases: plasma compression (thermal) and plasma expansion (nonthermal). …

Development Of Practical Method Using A Monte Carlo Code For Evaluation Of Optimum Fuel Pitch In A Typical Vver-1000 Core, Navid Taheranpoura, Ahmad Talaei

Ahmad Talaei

In this work, we developed a practical method to evaluate the optimum moderator-to-fuel ratio of a typical VVER reactor using a Monte Carlo code. To reach this aim, by analyzing the curves of the infinite multiplication factor (k_∞) versus moderator-to-fuel ratio, the optimum fuel pitch is determined for different fuel diameters of the proposed fuel elements using the MCNPX code. Optimum moderator-to-fuel ratio and fuel pitch were determined from the curves where the value of k_∞ is maximum for cold conditions and is located in an under-moderated region for hot conditions. Also, the void reactivity coefficient …

Investigation Of The High Pressure Regimes Effects On The Neutron Production In Plasma Focus, Ahmad Talaei, S.M. Kaia

Ahmad Talaei

Effects of high pressure regimes on the thermal mechanism of neutron yield and anisotropy factor with respect to the capacitor bank energy are presented by using moving boiler model. It is found that at high pressures, the thermal fusion reactions have a considerable effect on the neutron yield and anisotropy factor. We have compared the manner of the anisotropy in two low and high pressure discharges to investigate different behavior of the anisotropy factor as a function of bank energy in the difference working regimes of pressure for Dena PF.

Exploring The Dimensions Of Nomophobia: Developing And Validating A Questionnaire Using Mixed Methods Research, Caglar Yildirim

Caglar Yildirim

Nomophobia is defined as the fear of being out of mobile phone contact and is considered a modern age phobia introduced to our lives as a byproduct of the interaction between people and mobile information and communication technologies, especially smartphones. This research study sought to contribute to the nomophobia research literature by identifying and describing the dimensions of nomophobia and developing a questionnaire to measure nomophobia. Consequently, this study adopted a two-phase, exploratory sequential mixed methods design. The first phase was a qualitative exploration of nomophobia through semi-structured interviews conducted with nine undergraduate students at a large Midwestern university in …

Magnetic Properties Of (Γ-Fe₂O₃)₈₀Ag₂₀ Nanocomposites Prepared In Reverse Micelles, Joan Wiemann, Jianbiao Dai, Jinke Tang, Gary Long, Leonard Spinu

Jinke Tang

The magnetic properties of nanoparticles of γ-Fe2O3 prepared by reverse micelles have been studied by dc magnetization, transverse ac susceptibility, and Mössbauer spectroscopy. The nanoparticles of γ-Fe2O3 in the nanocomposite (γ- Fe2 O3) 80Ag20 exhibit superparamagnetic behavior. The blocking temperatures determined by the three methods indicate the superparamagnetic nature of (γ- Fe2 O3) 80Ag20 above 70-80 K and show correlation with measuring time. The average particle diameter obtained by transmission electron microscopy of the γ-Fe2O3 particles is 10 nm and that of the Ag particles is 20 nm. The average particle size determined from the magnetic analyses for the γ-Fe2O3 …

Effect Of Gadolinium Doping On The Electronic Band Structure Of Europium Oxide, Juan Colon Santana, Joonhee Michael An, Ning Wu, Kirill Belashchenko, Xianjie Wang, Pan Liu, Jinke Tang, Yaroslav Losovyj, I. N. Yakovkin, Peter Dowben

Jinke Tang

High quality films of EuO and Eu_0.96Gd_0.04O were grown on p-type Si(100) via pulsed laser deposition. X-raydiffraction results show that the addition of Gd changes the growth texture from [001] to [111]. Angular-resolved photoemission spectroscopy reveals electron pockets around the X points in Gd-doped EuO, indicating that the band gap in EuO is indirect. Combined photoemission and inverse photoemission measurements showan apparent transition from n-type to p-type behavior, which is likely due to band bending near the polar (111) surface.

Teaching College General Chemistry: Techniques Designed To Communicate A Conceptual Framework, Ronald Duchovic

Ronald J. Duchovic

General chemistry at the college level is often perceived as a major hurdle by typical undergraduates. Both Freshmen and more advanced students undertake courses in general chemistry either ill-prepared or convinced that the subject matter is beyond their comprehension. With the exception of potential chemistry majors, the vast majority of general chemistry students enter the class simply to satisfy a graduation requirement of their degree program. Consequently, instructors must both communicate an understanding of the subject matter and overcome major barriers to the learning process itself. This paper discusses two techniques which have been utilized for five semesters in general …

Potlib 2001: A Potential Energy Surface Library For Chemical Systems, Ronald Duchovic, Y Volobuev, G Lynch, D Truhlar, T Allison, A Wagner, B Garret, J Corchado

Ronald J. Duchovic

POTLIB 2001 is a computer program library of global chemical potential energy surface (PES) functions (91 functions in version 1.0) along with test data, a suite of utility programs, and a convenient user interface. The PES programs are written in ANSI standard FORTRAN77 and can be used to determine the Born–Oppenheimer potential energy of chemical systems as a function of the internal coordinates. The accompanying test data allow users to verify local implementations of this library. Finally, the utility programs permit use of this library in conjunction with a variety of chemical dynamics and chemical kinetics computer codes. Interface routines …

Thermal Rate Constants For H + Ch3  Ch4 Recombination. Ii. Comparison Of Experiment And Canonical Variational Transition State Theory, W Hase, S Mondro, Ronald Duchovic, D Hirst

Ronald J. Duchovic

Canonical variational transition state theory is used to calculate bimolecular rate constants for H + CH, and D + CH, recombination. The calculations are performed on an analytic potential energy surface derived from recent ab initio calculations. Rate constants calculated for this surface are in very good agreement with the experimental values. The H(D)- - -CH3 transitional rocking modes are treated as quantum harmonic oscillators or classical hindered rotors in the calculations. These two treatments give rate constants which agree to within 15%. The variational transition states become tighter as the temperature is increased.

An Application Of Conventional Transition State `Theory To Compute High--Pressure Limit Thermal Rate Coefficients For The Reaction: H(D) + O2  H(D)O2*  Oh(D) + O, Ronald Duchovic, J Pettigrew

Ronald J. Duchovic

Several ab initio studies have focused on the minimum energy path region of the hydroperoxyl potential energy surface (PES) (J. Chem. Phys. 1988, 88, 6273) and the saddle point region for H-atom exchange via a T-shaped HO2 complex (J. Chem. Phys. 1989, 91, 2373). Further, the results of additional calculations (J. Chem. Phys. 1991, 94, 7068) have been reported which, when combined with the earlier studies, provide a global description (but not an analytic representation) of the PES for this reaction. In this work, information at the stationary points of the ab initio PES is used within the framework of …

Observations Of Mesospheric Gravity Wave Dynamics In The Southern Hemisphere, Jonathan Pugmire, Michael Taylor

Jonathan Pugmire

Observations of mesospheric OH rotational temperature by the Mesospheric Temperature Mapper located at Cerro Pachon, Chile (30.3°S, 70.7°S) show a large range of variation. Temperature variances reveal increased activity due to mountain waves. Comparative studies with the satellite carried SABER instrument show agreement on nightly, as well as seasonal, temperature measurements. Comparisons with similar temperature measurements from Maui, Hawaii (20.8°N) reveal mountain wave activity to be enhanced over the Andes in the winter months. Initial gravity wave measurements from McMurdo Base, Antarctica are highlighted.

Mesospheric Temperature Variability And Seasonal Characteristics Over The Andes, Jonathan Pugmire, Yucheng Zhao, Michael Taylor, P Pautet

Jonathan Pugmire

The Utah State University CEDAR Mesospheric Temperature Mapper (MTM) is a high-quality CCD imager capable of remote sensing faint optical emissions from the night sky to determine mesospheric temperature and its variability at an altitude of ~87 km. The MTM was operated at the new Andes Lidar Observatory (ALO)located at Cerro Pachon, Chile (30.2° S, 70.7° W) since August 2009 to investigate the seasonal characteristic of the mesopause at mid-latitudes. Measurement were made alongside a powerful lidar capable of height sounding the mesosphere. In this study, the MTM data have been analyzed to determine night to night variability and seasonal …

The Lyman Alpha Reference Sample: Iii. Properties Of The Neutral Ism From Gbt And Vla Observations, Stephen Pardy, John Cannon, Göran Östlin, Matthew Hayes, Thøger Rivera-Thorsen, Andreas Sandberg, Angela Adamo, Emily Freeland, E. Herenz, Lucia Guaita, Daniel Kunth, Peter Laursen, J. Mas-Hesse, Jens Melinder, Ivana Orlitova, Hecto Otí-Floranes, Johannes Puschnig, Daniel Schaerer, Anne Verhamme

John Cannon

No abstract provided.

Virtual Inorganic Pedagogical Electronic Resource Learning Objects In Organometallic Chemistry, Barbara Reisner, Joanne Stewart, B Williams, Laurel Goj, Patrick Holland, Hilary Eppley, Adam Johnson

Hilary J. Eppley

Four Virtual Inorganic Pedagogical Electronic Resource (VIPEr) learning objects featuring organometallicChemistry are highlighted.

Building An Online Teaching Community: An Evolving Tale Ofcommunication, Collaboration, Andchemistry, Barbara Reisner, Hilary Eppley, Margret Geselbracht, Elizabeth Jamieson, Adam Johnson, Sheila Smith, Joanne Stewart, Lori Watson, Scott Williams

Hilary J. Eppley

The Interactive Online Network of Inorganic Chemists (IONiC) has grown from a small group of faculty to a national and international network focused on improving inorganicChemistry learning. IONiC’s vision is to create a community of teachers and learners who make teaching visible using social networking tools to share, discuss, test, and assess their teaching methods. The features that have allowed the IONiC community to develop and grow and IONiC’s vision for the future are described. It is likely that the lessons learned apply to other groups seeking to develop professional communities through social networking.

Inorganic Chemistry And Ionic: An Online Community Bringing Cutting-Edge Research Into The Classroom, Elizabeth Jamieson, Hilary Eppley, Margret Geselbracht, Adam Johnson, Barbara Reisner, Sheila Smith, Joanne Stewart, Lori Watson, B Williams

Hilary J. Eppley

This Viewpoint highlights creative ways that members of the Interactive Online Network of Inorganic Chemists (IONiC) are using journal articles from InorganicChemistry to engage undergraduate students in the classroom. We provide information about specificEducational materials and networking features available free of charge to the inorganic community on IONiC's web home, the Virtual Inorganic Pedagogical Electronic Resource (VIPEr, www.ionicviper.org) and describe the benefits of joining this community.

Ionic: A Cyber-Enabled Community Of Practice For Improving Inorganic Chemicaleducation, Hilary Eppley, Adam Johnson, Ethan Benatan, Margret Geselbracht, Joanne Stewart, Barbara Reisner, Lori Watson, B. Williams

Hilary J. Eppley

IONiC’s purpose is to enhance the inorganicChemistry classroom and laboratory experience for students and faculty members through the development of a vibrant virtual “community of practice”.

Jce Viper: An Inorganic Teaching And Learning Community, Ethan Benatan, Jezmynne Dene, Hilary Eppley, Margret Gesebracht, Elizabeth Jamieson, Adam Johnson, Barbara Reisner, Joanne Stewart, Lori Watson, B. Williams

Hilary J. Eppley

To facilitate the effective sharing of teaching tools among faculty and the development of deep subject knowledge in support of teaching, a group of faculty from predominantly undergraduate institutions has established a virtual community of inorganic chemists, IONiC (Interactive Online Network of Inorganic Chemists). Our mission is to enhance the inorganicChemistry classroom and laboratory experience for students and faculty members through the development of a vibrant, collaborative, and open community. VIPEr, the Virtual Inorganic Pedagogical Electronic Resource, is a Web site that forms the online home for our community. VIPEr is an interactive Web resource that combines a repository of …

Viper: An Online Academic Resource Enhancing Undergraduate Research, Sheila Smith, Sibrina Collins, Hilary Eppley, Margaret Geselbracht, Elizabeth Jamieson, Adam Johnson, Chip Nataro, Barbara Reisner, Joanne Stewart, B. Williams, Lori Watson

Hilary J. Eppley

No abstract provided.

Unconventional Gas Development: Why A Regional Community Said No, Hanabeth Luke, David Lloyd, William Boyd, Kristin Den Exter

Dr Kristin den Exter

Public concern resulting from unconventional coal seam gas (CSG) exploration and production has become a contentious planning issue in regional Australia, with public concern drawing attention to government planning obligations. To assist Lismore City Council (Northern New South Wales) in its deliberations on the topic, a referendum-style poll on the issue of CSG industry development was held in conjunction with the local government elections of September 2012. The poll question, ‘Do you support CSG exploration and production in the Lismore City Council area?’, elicited a poll response rate of 97% of eligible voters, of which 87% voted ‘no’. This paper …

Effects Of Particle Shape On Growth Dynamics At Edges Of Evaporating Drops Of Colloidal Suspensions, Peter Yunker, Matthew Lohr, Tim Still, Alexei Borodin, Douglas Durian, Arjun Yodh

Douglas J. Durian

We study the influence of particle shape on growth processes at the edges of evaporating drops. Aqueous suspensions of colloidal particles evaporate on glass slides, and convective flows during evaporation carry particles from drop center to drop edge, where they accumulate. The resulting particle deposits grow inhomogeneously from the edge in two dimensions, and the deposition front, or growth line, varies spatiotemporally. Measurements of the fluctuations of the deposition front during evaporation enable us to identify distinct growth processes that depend strongly on particle shape. Sphere deposition exhibits a classic Poisson-like growth process; deposition of slightly anisotropic particles, however, belongs …