Physics Commons^™

Thermal And X-Ray Investigations Of Kowak Clay In Northwestern Tanzania And Its Possible Industrial Use, E. H. J. Lugwisha

Tanzania Journal of Science

A study of some properties of clays collected from selected sites in Kowak deposit in Tarime District was carried out in order to assess their suitability as raw materials in ceramic and its related industries. The silica (SiO2) content in the clays is predominant, and is about 66.89% followed by alumina (Al2O3) that is 20.2%. Haematite (Fe2O3) was found to be the third in abundance with an average of 3.58%. Other constituents are present in small proportions. Water loss at 105 oC lies between 2.70% and 2.76%. DTG, TG, XRD techniques and chemical analyses studied by AAS method were used …

Coastal Tanzania, A New Home To The Living Coelacanth: An Oceanographic Analysis, N. Nyandwi

Tanzania Journal of Science

Coelacanth is no longer a new fish in Tanzania. After it was first discovered in September 2003 off Kilwa Masoko in southern Tanzania and with awareness campaigns, fishermen have reported further landings since, mostly in Tanga, northern Tanzania at Kigombe village. Analysis of habitat conditions suitable for the coelacanth indicates that the oceanography may just be right for the fish to have a permanent residence as opposed to the theory of drifters from a natural home elsewhere. At one time three specimens were captured together in the same net indicating that they formed a group. Oceanographic studies of the habitat …

Afci Quarterly Input – Unlv October 1 Through December 31, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Scaling Tests Of The Cross Section For Deeply Virtual Compton Scattering, C. Muñoz Camacho, Timothy Holmstrom, Jefferson Lab Hall A Collaboration

Chemistry & Physics Faculty Publications

We present the first measurements of the e⃗p→epγ cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q² dependence (from 1.5 to 2.3  GeV²) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q². The helicity-independent cross section is also measured at Q²=2.3  GeV². We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.

An Investigation Of Thundersnow And Deep Snow Accumulations, Christina Crowe, Patrick Market, Brian Pettergrew, Chris Melick, Josef Podzimek

Physics Faculty Research & Creative Works

A comparison of 30 years of hourly surface weather observations (1960-1991) from first-order stations and 24-hour snowfall data from climate network stations over the upper Midwestern United States reveals an indirect association between the relatively rare occurrence of thundersnow (< 1 event yr-1 in this dataset) and the accumulation of significant 24-hour snowfall (> 15 cm) in 19 of 22 cases identified. Although no direct relationship is found between the location of thundersnow and the deepest 24-hour snow totals, significant snow accumulations frequently occurred in proximity (< 1° latitude) to thundersnow events. the presence of thundersnow tended to indicate a parent extratropical cyclone capable of producing significant snowfall totals; should thundersnow be anticipated, the operational meteorologist can have much greater confidence in forecasting deeper snow totals. Copyright 2006 by the American Geophysical Union.

The Coefficient Of Bohm Diffusion In Fully Ionized Plasma And Its Theoretical Proof, Ahmad Talaei, Reza Amrollahi

Graduate Student Presentations

As we know, the classical diffusion can not be able to respond the experimental results of the diffusion in the fully ionized and isothermal plasma. In this article, we purpose to extract the empirical coefficients of the Bohm diffusion and its confinement time, theoretically, in the fully ionized plasma, using the single fluid MHD equations.

Longitudinal Double-Spin Asymmetry And Cross Section For Inclusive Jet Production In Polarized Proton Collisions At √S = 200 Gev, B.I. Abelev, M.M. Aggarwal, Z. Ahammed, J. Amonett, B.D. Anderson, M. Anderson, D. Arkhipkin, G.S. Averichev, Y. Bai, J. Balewski, O. Barannikova, L.S. Barnby, J. Baudot, S. Bekele, V.V. Belaga, A. Bellingeri-Laurikainen, R. Bellwied, F. Benedosso, S. Bhardwaj, A. Bhasin, A.K. Bhati, H. Bichsel, J. Bielcik, J. Bielcikova, L.C. Bland, S-L. Blyth, B.E. Bonner, M. Botje, J. Bouchet, A.V. Brandin, A. Bravar, T.P. Burton, M. Bystersky, R.V. Cadman, X.Z. Cai, H. Caines, M. Calderón De La Barca Sánchez, J. Castillo, O. Catu, D. Cebra, Z. Chajecki, P. Chaloupka, S. Chattopadhyay, H.F. Chen, J.H. Chen, J. Cheng, M. Cherney, A. Chikanian, W. Christie, J.P. Coffin, T.M. Cormier, M.R. Cosentino, J.G. Cramer, H.J. Crawford, D. Das, S. Das, S. Dash, M. Daugherity, M.M. De Moura, T.G. Dedovich, M. Dephillips, A.A. Derevschikov, L. Didenko, T. Dietel, P. Djawotho, S.M. Dogra, W.J. Dong, X. Dong, J.E. Draper, F. Du, V.B. Dunin, J.C. Dunlop, M.R. Dutta Mazumdar, V. Eckardt, W.R. Edwards, L.G. Efimov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, M. Estienne, P. Fachini, R. Fatemi, J. Fedorisin, P. Filip, E. Finch, V. Fine, Y. Fisyak, J. Fu, C.A. Gagliardi, L. Gaillard, M.S. Ganti, V. Ghazikhanian, P. Ghosh, J.E. Gonzalez, Y.G. Gorbunov, H. Gos, O. Grebenyuk, D. Grosnick, S.M. Guertin, K.S.F.F. Guimaraes, N. Gupta, T. D. Gutierrez, B. Haag, T.J. Hallman, A. Hamed, J.W. Harris, W. He, M. Heinz, T.W. Henry, S. Hepplemann, B. Hippolyte, A. Hirsch, E. Hjort, A.M. Hoffman, G.W. Hoffmann, M.J. Horner, H.Z. Huang, S.L. Huang, E.W. Hughes, T.J. Humanic, G. Igo, P. Jacobs, W.W. Jacobs, P. Jakl, F. Jia, H. Jiang, P.G. Jones, E.G. Judd, S. Kabana, K. Kang, J. Kapitan, M. Kaplan, D. Keane, A. Kechechyan, V.Yu. Khodyrev, B.C. Kim, J. Kiryluk, A. Kisiel, E.M. Kislov, S.R. Klein, A. Kocoloski, D.D. Koetke, T. Kollegger, M. Kopytine, L. Kotchenda, V. Kouchpil, K.L. Kowalik, M. Kramer, P. Kravtsov, V.I. Kravtsov, K. Krueger, C. Kuhn, A.I. Kulikov, A. Kumar, A.A. Kuznetsov, M.A.C. Lamont, J.M. Landgraf, S. Lange, S. Lapointe, F. Laue, J. Lauret, A. Lebedev, R. Lednicky, C-H. Lee, S. Lehocka, M.J. Levine, C. Li, Q. Li, Y. Li, G. Lin, X. Lin, S.J. Lindenbaum, M.A. Lisa, F. Liu, H. Liu, J. Liu, L. Liu, Z. Liu, T. Ljubicic, W.J. Llope, H. Long, R.S. Longacre, W.A. Love, Y. Lu, T. Ludlam, D. Lynn, G.L. Ma, J.G. Ma, Y.G. Ma, D. Magestro, D.P. Mahapatra, R. Majka, L.K. Mangotra, R. Manweiler, S. Margetis, C. Markert, L. Martin, H.S. Matis, Yu.A. Matulenko, C.J. Mcclain, T.S. Mcshane, Yu. Melnick, A. Meschanin, J. Millane, M.L. Miller, N.G. Minaev, S. Mioduszewski, C. Mironov, A. Mischke, D.K. Mishra, J. Mitchell, B. Mohanty, L. Molnar, C.F. Moore, D.A. Morozov, M.G. Munhoz, B.K. Nandi, C. Nattrass, T.K. Nayak, J.M. Nelson, P.K. Netrakanti, L.V. Nogach, S.B. Nurushev, G. Odyniec, A. Ogawa, V. Okorokov, M. Oldenburg, D. Olson, M. Pachr, S.K. Pal, Y. Panebratsev, S.Y. Panitkin, A.I. Pavlinov, T. Pawlak, T. Peitzmann, V. Perevoztchikov, C. Perkins, W. Peryt, S.C. Phatak, R. Picha, M. Planinic, J. Pluta, N. Poljak, N. Porile, J. Porter, A.M. Poskanzer, M. Potekhin, E. Potrebenikova, B.V.K.S. Potukuchi, D. Prindle, C. Pruneau, J. Putschke, G. Rakness, R. Raniwala, S. Raniwala, R.L. Ray, S.V. Razin, J. Reinnarth, D. Relyea, A. Ridiger, H.G. Ritter, J.B. Roberts, O.V. Rogachevskiy, J.L. Romero, A. Rose, C. Roy, L. Ruan, M.J. Russcher, R. Sahoo, T. Sakuma, S. Salur, J. Sandweiss, M. Sarsour, P.S. Sazhin, J. Schambach, R.P. Scharenberg, N. Schmitz, J. Seger, I. Selyuzhenkov, P. Seyboth, A. Shabetai, E. Shahaliev, M. Shao, M. Sharma, W.Q. Shen, S.S. Shimanskiy, E. Sichtermann, F. Simon, R.N. Singaraju, N. Smirnov, R. Snellings, G. Sood, P. Sorensen, J. Sowinski, J. Speltz, H.M. Spinka, B. Srivastava, A. Stadnik, T.D.S. Stanislaus, R. Stock, A. Stolpovsky, M. Strikhanov, B. Stringfellow, A.A.P. Suaide, E. Sugarbaker, M. Sumbera, Z. Sun, B. Surrow, M. Swanger, T.J.M. Symons, A. Szanto De Toledo, A. Tai, J. Takahashi, A.H. Tang, T. Tarnowsky, D. Thein, J.H. Thomas, A.R. Timmins, S. Timoshenko, M. Tokarev, T.A. Trainor, S. Trentalange, R.E. Tribble, O.D. Tsai, J. Ulery, T. Ullrich, D.G. Underwood, G. Van Buren, N. Van Der Kolk, M. Van Leeuwen, A.M. Vander Molen, R. Varma, I.M. Vasilevski, A.N. Vasiliev, R. Vernet, S.E. Vigdor, Y.P. Viyogi, S. Vokal, S.A. Voloshin, W.T. Waggoner, F. Wang, G. Wang, J.S. Wang, X.L. Wang, Y. Wang, J.W. Watson, J.C. Webb, G.D. Westfall, A. Wetzler, C. A. Whitten Jr., H. Wieman, S.W. Wissink, R. Witt, J. Wood, J. Wu, N. Xu, Q.H. Xu, Z. Xu, P. Yepes, I-K. Yoo, V.I. Yurevich, W. Zhan, H. Zhang, W.M. Zhang, Y. Zhang, Z.P. Zhang, Y. Zhao, C. Zhong, R. Zoulkarneev, Y. Zoulkarneeva, A.N. Zubarev, J.X. Zuo

Physics

We report a measurement of the longitudinal double-spin asymmetry ALL and the differential cross section for inclusive midrapidity jet production in polarized proton collisions at √s=200  GeV. The cross section data cover transverse momenta 5

Thickness Profiles Through Fatigued Bulk Ceramic Lead Zirconate Titanate, Nina Balke, Doru C. Lupascu, Thomas Blair

Alexei Gruverman Publications

Wedge-cut samples of fatigued ferroelectric lead zirconate titanate ceramics were investigated using piezoresponse force microscopy in conjunction with conventional electrical hysteresis measurements. The local clamping of domains is monitored at different depths in the sample. The coercive fields in grains near the electrodes differ for different materials and preparation methods of the electrodes. For silver, fatigue consistently generates a space charge in the depth of the sample. For platinum electrodes, the fatigue behavior scatters strongly. Microscopically, it either occurs directly underneath the electrodes or resembles the behavior of the silver electrodes in other samples.

Structure Inhomogeneities, Shallow Defects, And Charge Transport In The Series Of Thermoelectric Materials K2bi8−Xsbxse13, Jeffrey S. Dyck, T. Kyratski, E. Hatzikraniotis, K. M. Paraskevopoulos, C. D. Malliakas, C. Uher, M. G. Kanatzidis

Physics

The charge transport properties of the low-dimensional thermoelectric materials K₂Bi_8-xSb_xSe₁₃ (02Bi_8-xSb_xSe₁₃ was analyzed on the basis of the classical semiconductor theory and discussed in the context of recent band calculations. The results suggest that the K₂Bi_8-xSb_xSe₁₃ materials possess coexisting domains with semimetallic and semiconducting characters whose ratio is influenced by the value of x and by local defects. The extent and relative distribution of these domains control the charge transport properties. Electron diffraction experiments performed on samples of K_{2 …}

Measurement Of The BS0 Lifetime Using Semileptonic Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

We report a measurement of the B_s⁰ lifetime in the semileptonic decay channel B_s⁰ → D_s^- μ⁺νX (and its charge conjugate), using approximately 0.4 fb^-1 of data collected with the D0 detector during 2002–2004. Using 5176 reconstructed D_s^- μ⁺ signal events, we have measured the B_s⁰ lifetime to be τ(B_s⁰) = 1.398 ± 0.044(stat) _-0.025^+0.028(syst) ps. This is the most precise measurement of the B_s⁰ lifetime to date.

Model For Light Scalars In Qcd, Joseph Schechter, Amir H. Fariborz, Renata Jora

Physics - All Scholarship

We propose a systematic procedure to study a generalized linear sigma model which can give a physical picture of possible mixing between q{\bar q} and qq{\bar q}{\bar q} low lying spin zero states. In the limit of zero quark masses, we derive the model independent results for the properties of the Nambu Goldstone pseudoscalar particles. For getting information on the scalars it is necessary to make a specific choice of terms. We impose two plausible physical criteria - the modeling of the axial anomaly and the suppression of effective vertices representing too many fermion lines - for limiting the large …

Measurement Of BD Mixing Using Opposite-Side Flavor Tagging, V. M. Abazov, Kenneth A. Bloom, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We report on a measurement of the B_d⁰ mixing frequency and the calibration of an opposite-side flavor tagger in the D0 experiment. Various properties associated with the b quark on the opposite side of the reconstructed B meson are combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance is tested with data, using a large sample of reconstructed semileptonic B → μD⁰X and B → μD^*X decays, corresponding to an integrated luminosity of approximately 1 fb^-1. The events are divided into groups depending on …

Harmonic Detection Of Resonance In Micro- And Nano- Cantilevers, Jay Gaillard

All Dissertations

Over the past decade there has been an explosion in the study of cantilevered beams on the micron and submicron dimension. The applications and research that involve these structures include state-of-the-art electronic components, sensors, and more recently, studies aimed at elucidating the mechanical properties of cantilevered carbon nanotubes and semiconducting nanowires. In nanoelectro-mechanical systems (NEMS), it is desirable to develop a capacitive readout method involving only two electrodes that are fully compliant with standard CMOS technology. However, the main drawback with this method is the ability to detect resonance in the presence of parasitic capacitance, which is due to the …

Assembly And Modification Of A Hyperthermal And Low Energy Ion Beamline For Detecting Electron-Hole Pair Production In Schottky Diodes, Matthew Ray

All Theses

A hyperthermal and low energy ion beamline to measure electron-hole pair production due to ion bombardment of Schottky diodes has been modified and assembled.
A brief overview of the instrument is given and the reason for operating the ion beamline in the hyperthermal and low energy regime is discussed. The capabilities of the ion beamline are unique and provide the means to measure quantities that offer insight into various energy exchange mechanisms that occur at surfaces. Combined with the ability to accept Schottky diode samples, the beamline is capable of measuring both charge transfer and electron-hole pair production caused by …

Geometry, Electronic Properties, And Thermodynamics Of Pure And Al-Doped Li Clusters, Mal-Soon Lee, Gowtham S, Haiying He, Kah Chun Lau, Lin Pan, D G. Kanhere

Data Science Publications

The first-principles density functional molecular dynamics simulations have been carried out to investigate the geometric, the electronic, and the finite temperature properties of pure Li clusters (Li₁₀, Li₁₂) and Al-doped Li clusters (Li₁₀Al, Li₁₀Al₂). We find that the addition of two Al impurities in Li₁₀ results in a substantial structural change, while the addition of one Al impurity causes a rearrangement of atoms. Introduction of Al impurities in Li₁₀ establishes a polar bond between Li and nearby Al atom(s), leading to a multicentered bonding, which weakens the Li-Li …

Why Should Primordial Perturbations Be In A Vacuum State?, Christian Armendariz-Picon

Physics - All Scholarship

In order to calculate the power spectrum generated during a stage of inflation, we have to specify the quantum state of the inflaton perturbations, which is conventionally assumed to be the Bunch-Davies vacuum. We argue that this choice is justified only if the interactions of cosmological perturbations are strong enough to drive excited states toward the vacuum. We quantify this efficiency by calculating the decay probabilities of excited states to leading order in the slow-roll expansion in canonical single-field inflationary models. These probabilities are suppressed by a slow-roll parameter and the squared Planck mass, and enhanced by ultraviolet and infrared …

Proton-Λ Correlations In Central Au+Au Collisions At √SNn = 200 Gev, J. Adams, M.M. Aggarwal, Z. Ahammed, J. Amonett, B.D. Anderson, D. Arkhipkin, G.S. Averichev, S.K. Badyal, Y. Bai, J. Balewski, O. Barannikova, L.S. Barnby, J. Baudot, S. Bekele, V.V. Belaga, A. Bellingeri-Laurikainen, R. Bellwied, J. Berger, B.I. Bezverkhny, S. Bharadwaj, A. Bhasin, A.K. Bhati, V.S. Bhatia, H. Bichsel, J. Bielcik, J. Bielcikova, A. Billmeier, L.C. Bland, C.O. Blyth, S.-L. Blyth, B.E. Bonner, M. Botje, A. Boucham, J. Bouchet, A.V. Brandin, A. Bravar, M. Bystersky, R.V. Cadman, X.Z. Cai, H. Caines, M. Calderón De La Barca Sánchez, J. Castillo, O. Catu, D. Cebra, Z. Chajecki, P. Chaloupka, S. Chattopadhyay, H.F. Chen, J.H. Chen, Y. Chen, J. Cheng, M. Cherney, A. Chikanian, H.A. Choi, W. Christie, J.P. Coffin, T.M. Cormier, M.R. Cosentino, J.G. Cramer, H.J. Crawford, D. Das, S. Das, M. Daugherity, M.M. De Moura, T.G. Dedovich, M. Dephillips, A.A. Derevschikov, L. Didenko, T. Dietel, S.M. Dogra, W.J. Dong, X. Dong, J.E. Draper, F. Du, A.K. Dubey, V.B. Dunin, J.C. Dunlop, M.R. Dutta Mazumdar, V. Eckardt, W.R. Edwards, L.G. Efimov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, M. Estienne, P. Fachini, J. Faivre, R. Fatemi, J. Fedorisin, K. Filimonov, P. Filip, E. Finch, V. Fine, Y. Fisyak, K.S.F. Fornazier, J. Fu, C.A. Gagliardi, L. Gaillard, J. Gans, M.S. Ganti, F. Geurts, V. Ghazikhanian, P. Ghosh, J.E. Gonzalez, H. Gos, O. Grachov, O. Grebenyuk, D. Grosnick, S.M. Guertin, Y. Guo, A. Gupta, N. Gupta, T.D. Gutierrez, T.J. Hallman, A. Hamed, D. Hardtke, J.W. Harris, M. Heinz, T.W. Henry, S. Hepplemann, B. Hippolyte, A. Hirsch, E. Hjort, G.W. Hoffmann, M.J. Horner, H.Z. Huang, S.L. Huang, E.W. Hughes, T.J. Humanic, G. Igo, A. Ishihara, P. Jacobs, W.W. Jacobs, M. Jedynak, H. Jiang, P.G. Jones, E.G. Judd, S. Kabana, K. Kang, M. Kaplan, D. Keane, A. Kechechyan, V.Yu. Khodyrev, B.C. Kim, J. Kiryluk, A. Kisiel, E.M. Kislov, J. Klay, S.R. Klein, D.D. Koetke, T. Kollegger, M. Kopytine, L. Kotchenda, K.L. Kowalik, M. Kramer, P. Kravtsov, V.I. Kravtsov, K. Krueger, C. Kuhn, A.I. Kulikov, A. Kumar, R. Kh. Kutuev, A.A. Kuznetsov, M.A.C. Lamont, J.M. Landgraf, S. Lange, F. Laue, J. Lauret, A. Lebedev, R. Lednicky, C.-H. Lee, S. Lehocka, M.J. Levine, C. Li, Q. Li, Y. Li, G. Lin, S.J. Lindenbaum, M.A. Lisa, F. Liu, H. Liu, J. Liu, L. Liu, Q.J. Liu, Z. Liu, T. Ljubicic, W.J. Llope, H. Long, R.S. Longacre, M. Lopez-Noriega, W.A. Love, Y. Lu, T. Ludlam, D. Lynn, G.L. Ma, J.G. Ma, Y.G. Ma, D. Magestro, S. Mahajan, D.P. Mahapatra, R. Majka, L.K. Mangotra, R. Manweiler, S. Margetis, C. Markert, C. Markert, L. Martin, J.N. Marx, H.S. Matis, Yu.A. Matulenko, C.J. Mcclain, T.S. Mcshane, F. Meissner, Yu. Melnick, A. Meschanin, M.L. Miller, N.G. Minaev, C. Mironov, A. Mischke, D.K. Mishra, J. Mitchell, B. Mohanty, L. Molnar, C.F. Moore, D.A. Morozov, M.G. Munhoz, B.K. Nandi, S.K. Nayak, T.K. Nayak, J.M. Nelson, P.K. Netrakanti, V.A. Nikitin, L.V. Nogach, S.B. Nurushev, G. Odyniec, A. Ogawa, V. Okorokov, M. Oldenburg, D. Olson, S.K. Pal, Y. Panebratsev, S.Y. Panitkin, A.I. Pavlinov, T. Pawlak, T. Peitzmann, V. Perevoztchikov, C. Perkins, W. Peryt, V.A. Petrov, S.C. Phatak, R. Picha, M. Planinic, J. Pluta, N. Porile, J. Porter, A.M. Poskanzer, M. Potekhin, E. Potrebenikova, B.V.K.S. Potukuchi, D. Prindle, C. Pruneau, J. Putschke, G. Rakness, R. Raniwala, S. Raniwala, O. Ravel, R.L. Ray, S.V. Razin, D. Reichhold, J.G. Reid, J. Reinnarth, G. Renault, F. Retiere, A. Ridiger, H.G. Ritter, J.B. Roberts, O.V. Rogachevskiy, J.L. Romero, A. Rose, C. Roy, L. Ruan, M.J. Russcher, R. Sahoo, I. Sakrejda, S. Salur, J. Sandweiss, M. Sarsour, I. Savin, P.S. Sazhin, J. Schambach, R.P. Scharenberg, N. Schmitz, K. Schweda, J. Seger, I. Selyuzhenkov, P. Seyboth, E. Shahaliev, M. Shao, W. Shao, M. Sharma, W.Q. Shen, K.E. Shestermanov, S.S. Shimanskiy, E. Sichtermann, F. Simon, R.N. Singaraju, N. Smirnov, R. Snellings, G. Sood, P. Sorensen, J. Sowinski, J. Speltz, H.M. Spinka, B. Srivastava, A. Stadnik, T.D.S. Stanislaus, R. Stock, A. Stolpovsky, M. Strikhanov, B. Stringfellow, A.A.P. Suaide, E. Sugarbaker, M. Sumbera, B. Surrow, M. Swanger, T.J.M. Symons, A. Szanto De Toledo, A. Tai, J. Takahashi, A.H. Tang, T. Tarnowsky, D. Thein, J.H. Thomas, A.R. Timmins, S. Timoshenko, M. Tokarev, T.A. Trainor, S. Trentalange, R.E. Tribble, O.D. Tsai, J. Ulery, T. Ullrich, D.G. Underwood, G. Van Buren, N. Van Der Kolk, M. Van Leeuwen, A.M. Vander Molen, R. Varma, I.M. Vasilevski, A.N. Vasiliev, R. Vernet, S.E. Vigdor, Y.P. Viyogi, S. Vokal, S.A. Voloshin, W.T. Waggoner, F. Wang, G. Wang, G. Wang, X.L. Wang, Y. Wang, Y. Wang, Z.M. Wang, H. Ward, J.W. Watson, J.C. Webb, G.D. Westfall, A. Wetzler, C. A. Whitten Jr., H. Wieman, S.W. Wissink, R. Witt, J. Wood, J. Wu, N. Xu, Z. Xu, Z.Z. Xu, E. Yamamoto, P. Yepes, I-K. Yoo, V.I. Yurevich, I. Zborovsky, H. Zhang, W.M. Zhang, Y. Zhang, Z.P. Zhang, C. Zhong, R. Zoulkarneev, Y. Zoulkarneeva, A.N. Zubarev, J.X. Zuo

Physics

We report on p−Λ,p− ¯Λ¯ ,¯p¯−Λ, and ¯p¯− ¯Λ¯ correlation functions constructed in central Au-Au collisions at √s_NN=200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p−Λ and p− ¯Λ¯; correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The ¯p¯− Λ and p− ¯Λ¯ correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real …

Modified Control Software For Imaging Ultracold Atomic Clouds, Dwight L. Whitaker, A. Sharma, J. M. Brown

Pomona Faculty Publications and Research

A charge-coupled device (CCD) camera capable of taking high-quality images of ultracold atomic samples can often represent a significant portion of the equipment costs in atom trapping experiment. We have modified the commercial control software of a CCD camera designed for astronomical imaging to take absorption images of ultracold rubidium clouds. This camera is sensitive at 780 nm and has been modified to take three successive 16-bit images at full resolution. The control software can be integrated into a Matlab graphical user interface with fitting routines written as Matlab functions. This camera is capable of recording high-quality images at a …

Structural Study Of Mn-Doped Zno Fi Lms By Tem, Xingzhong Li, Jun Zhang, David J. Sellmyer

David Sellmyer Publications

The structural study of diluted magnetic semiconductors is important for interpreting the ferromagnetic behavior associated with the materials. In the present work, a series of low concentration Mn-doped ZnO thin films synthesized by pulsed laser deposition was studied by electron microscopy. All films show the wurtzite structure with (001) preferred growth orientation on the Si substrate. Electron diffraction experiments indicate the deterioration of the growth orientation in some areas of the films with increasing Mn concentration, and the existence of a secondary phase, of Mn₂O₃-type, in the films with larger Mn concentrations. High-resolution electron microscopy images …

Modulational Instability In A Layered Kerr Medium: Theory And Experiment, Martin Centurion, Mason A. Porter, Ye Pu, P. G. Kevrekidis, D. J. Frantzeskakis, Demetri Psaltis

Martin Centurion Publications

We present the first experimental investigation of modulational instability in a layered Kerr medium. The particularly interesting and appealing feature of our configuration, consisting of alternating glass-air layers, is the piecewise-constant nature of the material properties, which allows a theoretical linear stability analysis leading to a Kronig-Penney equation whose forbidden bands correspond to the modulationally unstable regimes. We find very good quantitative agreement between theoretical, numerical, and experimental diagnostics of the modulational instability. Because of the periodicity in the evolution variable arising from the layered medium, there are multiple instability regions rather than just one as in a uniform medium.

Lifecycle Analysis Of Cumulus Clouds Using A 3d Virtual Reality Environment, Thijs Heus, Harm J.J. Jonker, Eric J. Griffith, Frits H. Post

Physics Faculty Publications

No abstract provided.

Physics Department News, December 2006, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 5, Issue 2:

• Editor’s Note
• From the Chair
• What’s New at the University
• Faculty Highlights
• Staff Highlights
• PhysTEC
• International Week
• ICPEAC Program Meeting
• Student News
• Annual Student Awards
• Recent Graduates
• Department Roster
• Photo Gallery
• Feedback/Update Reply Form

The Influence Of The Sub-Cloud Moisture Field On Cloud Size Distributions And The Consequences For Entrainment, Harm J.J. Jonker, Remco A. Verzijlbergh, Thijs Heus, A. Pier Siebesma

Physics Faculty Publications

No abstract provided.

Why Do Descending Shells Around Cumulus Clouds Exist?, Thijs Heus, Harm J.J. Jonker

Physics Faculty Publications

No abstract provided.

Optical And X-Ray Variability Of Agns, C. Martin Gaskell

C. Martin Gaskell Publications

I present new comparisons of AGN optical, UV, and X-ray variations. These reveal complex relationships between the different passbands that can change with time in a given object. While there is evidence from several objects that X-ray and optical activity levels are correlated on long timescales, variations on shorter timescales can occur independently. It is proposed that the combination of correlated and uncorrelated short-timescale variability is a consequence of anisotropic high-energy emission. It is also argued that the correlation between X-ray and optical variability on long timescales must be due to a common underlying factor and not to reprocessing of …

Optical Variability Of The Three Brightest Nearby Quasars, C. Martin Gaskell, Andrew J. Benker, Jeffrey S. Campbell, Thomas A. George, Cecilia H. Hedrick, Mary E. Hiller, Elizabeth S. Klimek, Joseph P. Leonard, Shoji Masatoshi, Bradley W. Peterson, Kelly S. Peterson, Kelly M. Sanders

C. Martin Gaskell Publications

We report on the relative optical variability of the three brightest nearby quasars, 3C 273, PDS 456, and PHL 1811. All three have comparable absolute magnitudes, but PDS 456 and PHL 1811 are radio quiet. PDS 456 is a broadline object, but PHL 1811 could be classified as a high-luminosity Narrow-Line Seyfert 1 (NLS1). Both of the radio-quiet quasars show significant variability on a timescale of a few days. The seasonal rms V-band variability amplitudes of 3C 273 and PDS 456 are indistinguishable, and the seasonal rms variability amplitude of PHL 1811 was only exceeded by 3C 273 once in …

The Origin Of Wavelength-Dependent Continuum Delays In Agns – A New Model, C. Martin Gaskell

C. Martin Gaskell Publications

A model of wavelength-dependent lags in optical continuum variability of AGNs is proposed which avoids the problems of the popular “lamppost” model. Rather than being due to reprocessing of high-energy radiation from a hypothetical source above the accretion disk, the wavelength-dependent delays observed from the B to I bands are instead due to contamination of an intrinsically coherently variable continuum with the Wien tail of the thermal emission from the hot dust in the surrounding torus. The new model correctly gives the size, wavelength dependence, and luminosity dependence of the lags, and quantitatively predicts observed color hysteresis. The model also …

Mesospheric Gravity Waves Observed Near Equatorial And Low-Middle Latitude Stations: Wave Characteristics And Reverse Ray Tracing Results, C. M. Wrasse, T. Nakamura, H. Takahshi, A. F. Medeiros, Michael J. Taylor, D. Gobi, C. M. Denardini, J. Fechine, R. A. Buriti, A. Salatun, Suratno, E. Achmad, A. G. Admiranto

All Physics Faculty Publications

Gravity wave signatures were extracted from OH airglow observations using all-sky CCD imagers at four different stations: Cachoeira Paulista (CP) (22.7° S, 45° W) and São João do Cariri (7.4° S, 36.5° W), Brazil; Tanjungsari (TJS) (6.9° S, 107.9° E), Indonesia and Shigaraki (34.9° N, 136° E), Japan. The gravity wave parameters are used as an input in a reverse ray tracing model to study the gravity wave vertical propagation trajectory and to estimate the wave source region. Gravity waves observed near the equator showed a shorter period and a larger phase velocity than those waves observed at low-middle latitudes. …

Effects Of Temperature Gradients On Transverse Oscillations Of Solar Magnetic Flux Tubes, Shilpa Subramaniam

Physics Theses - Archive

Solar magnetic flux tubes support three fundamental modes: longitudinal, transverse and torsional tube waves. Previous studies showed that the propagation of longitudinal and transverse waves along thin and isothermal magnetic flux tubes is affected by the cutoff frequency, which are global quantities that restricts the wave propagation to only those frequencies that are higher than the cutoff. It was also demonstrated that the tubes respond to freely propagating longitudinal and transverse tube waves by oscillating at the corresponding cutoff frequency. No cutoff frequency was found for torsional waves propagating along thin and isothermal magnetic flux tubes. Since the solar atmosphere …

Spin-Lattice Relaxation Of Heavy Spin-1/2 Nuclei In Diamagnetic Solids: A Raman Process Mediated By Spin-Rotation Interaction, Alexander J. Vega, Peter A. Beckmann, Shi Bai, Cecil Dybowski

Physics Faculty Research and Scholarship

We present a theory for the nuclear spin-lattice relaxation of heavy spin-1/2 nuclei in solids, which explains within an order of magnitude the unexpectedly effective lead and thallium nuclear spin-lattice relaxation rates observed in the ionic solids lead molybdate, lead chloride, lead nitrate, thallium nitrate, thallium nitrite, and thallium perchlorate. The observed rates are proportional to the square of the temperature and are independent of magnetic field. This rules out all known mechanisms usually employed to model nuclear spin relaxation in lighter spin-1/2 nuclei. The relaxation is caused by a Raman process involving the interactions between nuclear spins and lattice …