Physics Commons^™

Adsorption-Controlled Growth Of Bivo4 By Molecular-Beam Epitaxy, D. A. Hillsberry, D. A. Tenne

Physics Faculty Publications and Presentations

Single-phase epitaxial films of the monoclinic polymorph of BiVO₄ were synthesized by reactive molecular-beam epitaxy under adsorption-controlled conditions. The BiVO₄ films were grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates. Four-circle x-ray diffraction, scanning transmission electron microscopy (STEM), and Raman spectroscopy confirm the epitaxial growth of monoclinic BiVO₄ with an atomically abrupt interface and orientation relationship (001)_BiVO4 ∥ (001)_YSZ with [100]_BiVO4 ∥ [100]_YSZ. Spectroscopic ellipsometry, STEM electron energy loss spectroscopy (STEM-EELS), and x-ray absorption spectroscopy indicate that the films have a direct band gap of 2.5 ± 0.1 eV.

Measurement Of [Special Characters Omitted] (Pp[Special Characters Omitted]Tt) In The[Special Characters Omitted]+ Jets Channel Using 4.7 Fb-1 Of Data From The Atlas Experiment Of The Large Hadron Collider, Anirvan Sircar

Doctoral Dissertations

The top quark is the heaviest of the known elementary particles in the Standard Model. Top quark decay can result into various final states; therefore, careful study of its production rate and other properties is very important for particle physics. With the shutdown of the Tevatron, The Large Hadron Collider (LHC) is the only facility currently capable of studying top quark properties. The data obtained by proton-proton collisions in the LHC is recorded by two general purpose detectors, ATLAS and CMS. The results in the dissertation are from the ATLAS detector. A new measurement is reported of &sgr;(pp [special …

Harmonic Generation In Multiresonant Plasma Films, Maria Antonietta Vincenti, Domenico De Ceglia, Joseph W. Haus, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We investigate second- and third-harmonic generation in a slab of material that displays plasma resonances at the pump and its harmonic frequencies. Near-zero refractive indices and local field enhancement can deplete the pump for kW/cm² incident powers, without resorting to other resonant photonic mechanisms. We show that low-threshold, highly efficient nonlinear processes are possible in the presence of losses and phase mismatch in structures that are 10⁴ times shorter than typical nonlinear crystals, for relatively low irradiance values.

Exploiting Neutron-Rich Radioactive Ion Beams To Constrain The Symmetry Energy, Z. Kohley, G. Christian, T. Baumann, Paul A. Deyoung, J. E. Finck, N. Frank, M. Jones, J. K. Smith, J. Snyder, A. Spyrou, M. Thoennessen

Faculty Publications

The Modular Neutron Array (MoNA) and 4 Tm Sweeper magnet were used to measure the free neutrons and heavy charged particles from the radioactive ion beam induced Mg-32 + Be-9 reaction. The fragmentation reaction was simulated with the constrained molecular dynamics model (CoMD), which demonstrated that the < N/Z > of the heavy fragments and free neutron multiplicities were observables sensitive to the density dependence of the symmetry energy at subsaturation densities. Through comparison of these simulations with the experimental data, constraints on the density dependence of the symmetry energy were extracted. The advantage of radioactive ion beams as a probe of the …

Phases And Phase Transitions In Disordered Quantum Systems, Thomas Vojta

Physics Faculty Research & Creative Works

These lecture notes give a pedagogical introduction to phase transitions in disordered quantum systems and to the exotic Griffiths phases induced in their vicinity. We first review some fundamental concepts in the physics of phase transitions. We then derive criteria governing under what conditions spatial disorder or randomness can change the properties of a phase transition. After introducing the strong-disorder renormalization group method, we discuss in detail some of the exotic phenomena arising at phase transitions in disordered quantum systems. These include infinite-randomness criticality, rare regions and quantum Griffiths singularities, as well as the smearing of phase transitions. We also …

Control System Of An Atomic Layer Deposition (Ald) Machine, Nitin Vishnu Hegde

Electrical & Computer Engineering Theses & Dissertations

Atomic Layer Deposition is one of the most efficient deposition processes for obtaining ultrathin films. The deposition by this process happens one atomic layer at a time. ALD is known for its precision and ability to develop quality films with great thickness control. ALD machines simultaneously control DC and AC currents, low pressure operations, temperature control and heating (up to 500'C), precision flow control, precision timing intervals for deposition (milli-second intervals) and constantly monitor temperature. Such a high control comes at a high price. Furthermore, at the university level, the capacity to modify or enhance a machine is critical but …

Synthesis And Optimization Of Vo₂ Thin Films For Phase Transition Applications By Atomic Layer Deposition And Rf Magnetron Sputtering, Madhavi Tangirala

Electrical & Computer Engineering Theses & Dissertations

Among many Vanadium oxides and suboxides, VO₂ has received considerable attention due to its remarkable metal-insulator transition (MIT) or semiconductor-metal transition (SMT) behavior, a reversible change in its electrical and optical properties that occurs due to a phase transition near a temperature of 68°C. Electrically, the resistivity of VO₂ can be changed as large as 4-5 orders of magnitude. Optically, the transmittance drops dramatically above the transition temperature in the metallic state where the VO₂ film becomes highly reflective in the infrared region. All these properties result in structural phase transformation from a low temperature monoclinic to …

Bayesian Approach For Uncertainty Analysis Of An Urban Storm Water Model And Its Applications To A Heavily Urbanized Watershed, Misgana K. Muleta, Jonathan Mcmillan, Geremew G. Amenu, Steven J. Burian

Physics

The significance of uncertainty analysis (UA) to quantify reliability of model simulations is being recognized. Consequently, literature on parameter and predictive uncertainty assessment of water resources models has been rising. Applications dealing with urban drainage systems are, however, very limited. This study applies formal Bayesian approach for uncertainty analysis of a widely used storm water management model and illustrates the methodology using a highly urbanized watershed in the Los Angeles Basin, California. A flexible likelihood function that accommodates heteroscedasticity, non-normality, and temporal correlation of model residuals has been used for the study along with a Markov-chain Monte Carlo-based sampling scheme. …

Measurement Of The Spin Structure Function Gd1 Of The Deuteron And Its Moments At Low Q2, Krishna P. Adhikari

Physics Theses & Dissertations

Double polarization cross section differences (Δσ ||) for proton and deuteron targets have been measured in the EG4 experiment using the CLAS detector at Jefferson Lab. Longitudinally polarized electron beams at relatively low energies of 1.056, 1.337, 1.989, 2.256 and 3.0 GeV from the CEBAF accelerator were scattered off longitudinally polarized NH₃ and ND₃ targets. Scattered electrons were recorded at very low scattering angles (down to θ= 6°) with the help of a new dedicated Cherenkov counter and a special magnetic field setting of the CLAS detector in order to measure the cross section differences in the …

Altered Cholesterol Metabolism In Human Cancers Unraveled By Label-Free Spectroscopic Imaging, Shuhua Yue

Open Access Dissertations

Despite tremendous scientific achievements, cancer remains the second leading cause of death in the United States. Metabolic reprogramming has been increasingly recognized as a core hallmark of cancer. My dissertation work identified novel diagnostic markers and therapeutic targets for human cancers through the study of cholesterol in cancer cells.

Enabled by label-free Raman spectromicroscopy, we performed the first quantitative analysis of lipogenesis at single cell level in human patient cancerous tissues. Our imaging data revealed an unexpected, aberrant accumulation of esterified cholesterol in lipid droplets of high-grade prostate cancer and metastases, but not in normal prostate, benign prostatic hyperplasia, or …

Atomistic Simulation Of Plasma Interaction With Plasma Facing Components In Fusion Reactors, Xue Yang

Open Access Dissertations

The interaction between plasma and fusion relevant materials is one of the critical issues in successfully using those materials in Tokamak reactors. This research uses molecular dynamics, kinetic Monte Carlo and binary collision approximation methods to model fusion relevant material bombarded by energetic particles to investigate retention, deposition, sputtering, erosion, blistering effects, diffusion, and so on.

The deuterium bombardment of monocrystalline tungsten was modeled by LAMMPS code using Tersoff type interatomic potential. The deuterium trapping rate, implantation depth, and stopping time in 600-2000 K tungsten bombarded by 5-100 eV deuterium atoms were simulated. Irradiated monocrystalline tungsten became amorphous prior to …

Design And Assembly Of Nanostructured Complex Metal Oxide Materials For The Construction Of Batteries And Thermoelectric Devices, Gautam Ganapati Yadav

Open Access Dissertations

Thermoelectric devices and lithium-ion batteries are among the fastest growing energy technologies. Thermoelectric devices generate energy from waste heat, whereas lithium-ion batteries store energy for use in commercial applications. Two different topics are bound with a common thread in this thesis - nanotechnology! In fact, nanostructuring is a more preferred term for the approach I have taken herein. Another commonality between these two topics is the material system I have used to prove my hypotheses - complex metal oxides.

Complex metal oxides can be used for both energy generation and storage as they are stable at high temperatures, are benign …

Biophysical Studies Of Cholesterol In Unsaturated Phospholipid Model Membranes, Justin Adam Williams

Open Access Dissertations

Cellular membranes contain a staggering diversity of lipids. The lipids are heterogeneously distributed to create regions, or domains, whose physical properties differ from the bulk membrane and play an essential role in modulating the function of resident proteins. Many basic questions pertaining to the formation of these lateral assemblies remain. This research employs model membranes of well-defined composition to focus on the potential role of polyunsaturated fatty acids (PUFAs) and their interaction with cholesterol (chol) in restructuring the membrane environment. Omega-3 (n-3) PUFAs are the main bioactive components of fish oil, whose consumption alleviates a variety of health problems by …

Gamma-Ray Observations Of X-Ray Binaries, Angelo Varlotta

Open Access Dissertations

The detection of GeV/TeV emission from X-ray binaries (XRBs) has established a new class of high-energy (HE, >0.1 GeV) and very-high-energy (VHE, >100 GeV) gamma-ray emitters. XRBs are formed by a compact object, either a neutron star or a black hole, and by an optical companion star. Some XRBs are known to possess collimated relativistic jets, and are called microquasars. VERITAS has conducted observations of the high-mass X-ray binary (HMXB) 1A 0535+262 and of the microquasar Cygnus X-3. Many theoretical models predict VHE emission when these sources manifest persistent relativistic jets or transient ejections. In light of these considerations, VERITAS …

The Formation Of Distal Impact Ejecta, Brandon C. Johnson

Open Access Dissertations

Here we present two models for the dynamics of ejection and formation of distal impact ejecta. The first model focuses on the most highly shocked material that forms a massive expanding vapor plume or fireball. In this model molten droplets or spherules condense from the vapor. We model the expanding vapor plume using a one dimensional Lagrangian hydrocode. The condensation of droplets is treated by directly coupling the equations for homogeneous nucleation and growth with our hydrocode. The second model is focused on less energetic material ejected as part of the excavation flow. Using the iSALE hydrocode, we determine the …

Measurement Of A Weak Transition Moment Using Coherent Control, Dionysios Antypas

Open Access Dissertations

We have developed a two-pathway Coherent Control technique for measurements of weak optical transition moments. We demonstrate this technique through a measurement of the transition moment of the highly-forbidden magnetic dipole transition between the 6s²S_1/21/2 and 7s²S_1/21/2 states in atomic Cesium. The experimental principle is based on a two-pathway excitation, using two phase-coherent laser fields, a fundamental field at 1079 nm and its second harmonic at 539.5 nm. The IR field induces a strong two-photon transition, while the 539.5 nm field drives a pair of weak one-photon transitions: a Stark-induced transition of …

Experimental Studies Of Lirb: Spectroscopy And Ultracold Molecule Formation By Photoassociation, Sourav Dutta

Open Access Dissertations

Heteronuclear polar molecules have recently attracted enormous attention owing to their ground state having a large electric dipole moment. The long range anisotropic dipole-dipole interaction in such systems is the basis for a variety of applications including quantum computing, precision measurements, ultracold chemistry and quantum simulations. Heteronuclear bi-alkali molecules, only a small subset of polar molecules, have received special attention mainly because the constituent alkali atoms are easy to laser cool and can be relatively easily associated to form molecules at ultracold temperatures. Our choice, the LiRb molecule, is motivated by the relatively high dipole moment (4.1 Debye) of the …

Applicability Of Continuum Fracture Mechanics In Atomistic Systems, Shao-Huan Cheng

Open Access Dissertations

By quantitating the amplitude of the unbounded stress, the continuum fracture mechanics defines the stress intensity factor K to characterize the stress and displacement fields in the vicinity of the crack tip, thereby developing the relation between the stress singularity and surface energy (energy release rate G). This G-K relation, assigning physical meaning to the stress intensity factor, makes these two fracture parameters widely used in predicting the onset of crack propagation. However, due to the discrete nature of the atomistic structures without stress singularity, there might be discrepancy between the failure prediction and the reality of nanostructured materials. Defining …

Nanoscale Semiconductor Materials And Devices Employing Hybrid 1d And 2d Structures For Tunable Electronic And Photonic Applications, Suprem Ranjan Das

Open Access Dissertations

Das, Suprem R. Ph.D., Purdue University, December 2013. Nanoscale Semiconductor Materials and Devices employing Hybrid 1D and 2D structures for Tunable Electronic and Photonic Applications. Major Professor: Dr. David B. Janes.

Continued miniaturization of microelectronic devices over past decades has brought the device feature size towards the physical limit. Likewise, enormous `waste energy' in the form of self-heating in almost all of the electronic and optoelectronic devices needs an `energy-efficient low power' and `high performance' material as well as device with alternate geometry. III-V semiconductors are proven to be one of the alternate systems of materials for various applications including …

Measuring The Angle-Dependent Photoionization Cross Section Of Nitrogen Using High-Harmonic Generation, Xiaoming Ren, Varun Makhija, Anh-Thu Le, Jan Troß, Sudipta Mondal, Cheng Jin, Vinod Kumarappan, Carlos A. Trallero-Herrero

Physics Faculty Research & Creative Works

We exploit the relationship between high harmonic generation (HHG) and the molecular photorecombination dipole to extract the molecular-frame differential photoionization cross section (PICS) in the extreme ultraviolet (XUV) for molecular nitrogen. A shape resonance and a Cooper-type minimum are reflected in the pump-probe time delay measurements of different harmonic orders, where high-order rotational revivals are observed in N₂. We observe the energy- and angle-dependent Cooper minimum and shape resonance directly in the laboratory-frame HHG yield by achieving a high degree of alignment, [SEE FORMULA IN ABSTRACT cos2 θ] 0.8. The interplay between PICS and rotational revivals is confirmed by simulations …

Fcnc Top Quark Production Via Anomalous Couplings, Nikolaos Kidonakis, Elwin Martin

Faculty Articles

We calculate flavor-changing neutral current (FCNC) processes with top-quark production via anomalous couplings at LHC energies. We report on progress on the FCNC processes gu -> tZ, gu -> t gamma and gu -> tg. We go beyond leading order and include soft-gluon corrections through next-to-next-to-leading order.

On The Origin Of Mode- And Bond-Selectivity In Vibrationally Mediated Reactions On Surfaces, Daniel Killelea, Arthur L. Utz

Chemistry: Faculty Publications and Other Works

The experimental observations of vibrational mode- and bond-selective chemistry at the gas–surface interface indicate that energy redistribution within the reaction complex is not statistical on the timescale of reaction. Such behavior is a key prerequisite for efforts to use selective vibrational excitation to control chemistry at the technologically important gas–surface interface. This paper outlines a framework for understanding the origin of non-statistical reactivity on surfaces. The model focuses on the kinetic competition between intramolecular vibrational energy redistribution (IVR) within the reaction complex, which in the long-time limit leads to statistical behavior, and quenching, scattering, or desorption processes that restrict the …

Response To David Quigley, John D. Cunningham

Physics: Faculty Publications and Other Works

No abstract provided.

Photon Counting Compressive Depth Mapping, Gregory A. Howland, Daniel J. Lum, Matthew R. Ware, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We demonstrate a compressed sensing, photon counting lidar system based on the single-pixel camera. Our technique recovers both depth and intensity maps from a single under-sampled set of incoherent, linear projections of a scene of interest at ultra-low light levels around 0.5 picowatts. Only two-dimensional reconstructions are required to image a three-dimensional scene. We demonstrate intensity imaging and depth mapping at 256 × 256 pixel transverse resolution with acquisition times as short as 3 seconds. We also show novelty filtering, reconstructing only the difference between two instances of a scene. Finally, we acquire 32 × 32 pixel real-time video for …

Efektivitas Sekolah Menengah Kejuruan Berstandar Iso 9001:2008 Terhadap Pencapaian Standar Isi, Standar Proses, Dan Standar Kompetensi Lulusan, Yeni Ratih Pratiwi

Jurnal Pendidikan Sains

Penelitian ini bertujuan untuk mengetahui perbedaan efektivitas pencapaian standar isi, standar proses, dan standar kompetensi lulusan pada Sekolah Menengah Kejuruan (SMK) yang telah menerapkan standar mutu ISO 9001:2008 dan SMK yang belum menerapkannya, baik pada sekolah negeri maupun swasta. Pengumpulan data dilakukan menggunakan kuesioner tertutup dengan skala Likert. Analisis data menggunakan uji ANOVA satu arah dengan bantuan program SPSS. Hasil penelitian menunjukkan bahwa terdapat perbedaan efektivitas antara SMK negeri berstandar ISO dan SMK swasta berstandar ISO (p = 0,001), antara SMK negeri berstandar ISO dan SMK negeri belum berstandar ISO (p = 0,000), serta antara SMK negeri berstandar ISO dan …

Pengaruh Penggunaan Peta Konsep Dalam Pembelajaran Inkuiri Terbimbing Ditinjau Dari Kemampuan Bernalar Siswa Kelas Xi, Agung Wahyudi

Jurnal Pendidikan Sains

Penelitian ini bertujuan untuk: (1) mengetahui perbedaan hasil belajar fisika antara siswa yang belajar menggunakan pembelajaran inkuiri terbimbing melalui peta konsep (PITPK) dan siswa yang belajar menggunakan pembelajaran inkuiri terbimbing (PIT); (2) menguji interaksi antara model pembelajaran dan kemampuan bernalar terhadap hasil belajar fisika; (3) mengetahui efektivitas PITPK dibandingkan PIT pada siswa dengan kemampuan bernalar tinggi; dan (4) mengetahui efektivitas PITPK dibandingkan PIT pada siswa dengan kemampuan bernalar rendah. Penelitian ini menggunakan rancangan faktorial 2 × 2 dengan teknik pengambilan sampel simple random sampling. Instrumen penelitian meliputi instrumen perlakuan berupa silabus, RPP, dan lembar observasi keterlaksanaan pembelajaran, serta instrumen pengukuran …

Pengaruh Pendekatan Genius Learning Berbasis Kerja Ilmiah Terhadap Prestasi Belajar Fisika Ditinjau Dari Pengetahuan Awal Siswa Smpn 13 Balikpapan Tahun 2012, Suliyono Suliyono

Jurnal Pendidikan Sains

Penguasaan konsep-konsep fisika siswa akan lebih optimal apabila pendidik menerapkan strategi pembelajaran yang mampu meningkatkan keaktifan dan motivasi belajar siswa dengan tetap berlandaskan pada pendekatan konstruktivis. Pendekatan Genius Learning Berbasis Kerja Ilmiah (GLBKI) diyakini mampu menjawab tuntutan perkembangan pendidikan serta mempermudah siswa dalam mempelajari konsep-konsep fisika. Penelitian ini bertujuan untuk menguji perbedaan prestasi belajar fisika antara siswa yang belajar menggunakan pendekatan Genius Learning Berbasis Kerja Ilmiah dan siswa yang belajar menggunakan pembelajaran konvensional. Penelitian ini menggunakan desain eksperimen dengan pemberian perlakuan berupa pendekatan GLBKI pada kelas eksperimen yang dipilih secara acak, sedangkan kelas kontrol diberikan pembelajaran konvensional. Data prestasi belajar …

Peer Mediated Instruction And Intervention (Pmii) Tipe Classwide Peer Tutoring (Cwpt) Dan Kemampuan Akademik Pada Pembelajaran Ipa Biologi Smk, Hamsiah Hamsiah

Jurnal Pendidikan Sains

Pembelajaran IPA di SMKN 1 Bontang masih didominasi dengan strategi belajar konvensional yaitu metode belajar dengan ceramah. Hal ini berdampak terhadap hasil belajar kognitif IPA biologi yang cenderung masih rendah karena siswa belum terlatih menjadi pebelajar yang mandiri, sehingga inovasi pembelajaran PMII tipe CWPT dapat digunakan sebagai terobosan untuk mengembangkan hasil belajar kognitif. Penelitian ini dilakukan untuk mengetahui penerapan strategi CWPT dan kemampuan akademik pada pembelajaran IPA Biologi SMK. Penelitian eksperimen semu dengan rancangan pretest-posttest Nonequivalent Control Group. Hasil penelitian, yaitu: (1) ada pengaruh CWPT terhadap hasil belajar kognitif, (2) ada pengaruh kemampuan akademik terhadap hasil belajar kognitif, dan (3) …

Pengaruh Penerapan Model Pembelajaran Pemerolehan Konsep Dipadu Pembelajaran Kooperatif Stad Terhadap Prestasi Belajar, Keaktifan, Dan Respons Siswa Pada Pembelajaran Ikatan Kimia, Putri Ridha Ilahi

Jurnal Pendidikan Sains

Penelitian ini bertujuan untuk mengetahui perbedaan: (1) prestasi belajar siswa menggunakan model pembelajaran pemerolehan konsep dipadu pembelajaran kooperatif STAD dan prestasi belajar siswa menggunakan model pembelajaran pemerolehan konsep dalam pembelajaran konvensional; (2) keaktifan siswa menggunakan model pembelajaran pemerolehan konsep dipadu pembelajaran kooperatif STAD dan keaktifan siswa menggunakan model pembelajaran pemerolehan konsep dalam pembelajaran konvensional; (3) respon siswa terhadap pembelajaran pemerolehan konsep dipadu pembelajaran kooperatif STAD dan respon siswa terhadap pembelajaran pemerolehan konsep dalam pembelajaran konvensional. Penelitian ini menggunakan rancangan penelitian deskriptif dan rancangan eksperimen semu (quasy experiment design). Data prestasi belajar dikumpulkan menggunakan tes objektif dan koefisien reliabilitas dihitung dengan …

Degradasi Anaerob Sampah Organik Dengan Bioaktivator Effective Microorganism-5 (Em-5) Untuk Menghasilkan Biogas, Metri Dian Insani

Jurnal Pendidikan Sains

Tujuan penelitian ini adalah untuk: (1) menganalisis perbedaan penggunaan tongkol jagung, kelaras pisang, dan kulit pisang dengan penambahan kotoran sapi terhadap tekanan biogas, (2) menganalisis perbedaan penggunaan tongkol jagung, kelaras pisang, dan kulit pisang dengan penambahan kotoran sapi terhadap lama waktu nyala api biogas yang dihasilkan, dan (3) menganalisis perbedaan penggunaan tongkol jagung, kelaras pisang, dan kulit pisang dengan penambahan kotoran sapi terhadap rasio C/N akhir. Penelitian eksperimen didesain menggunakan rancangan acak lengkap (RAL), dengan tiga perlakuan masing-masing dalam 3 kali ulangan. Hasil penelitian membuktikan bahwa: (1) terdapat perbedaan tongkol jagung, kelaras pisang, dan kulit pisang dengan penambahan kotoran sapi …