Probing Quarkonium Production Mechanisms with Jet Substructure

We use fragmenting jet functions (FJFs) in the context of quarkonia to study the production channels predicted by NRQCD (3S_1^(1), 3S_1^(8), 1S_0^(8), 3P_J^(8)). We choose a set of FJFs that give the probability to find a quarkonium with a given momentum fraction inside a cone-algorithm jet with fixed cone size and energy. This observable gives several lever arms that allow one to distinguish different production channels. In particular, we show that at fixed momentum fraction the individual production mechanisms have distinct behaviors as a function of the the jet energy. As a consequence of this fact, we arrive at the robust prediction that if the depolarizing 1S_0^(8) matrix element dominates, then the gluon FJF will diminish with increasing energy for fixed momentum fraction, z, and z > 0.5.Comment: 13 pages, 6 figures; v2: Typos fixed, figures updated and new figure added to reflect nontrivial error correlation in long-distance matrix element determination which leads to stronger prediction for our observables; v3: Operational discussion of fragmenting jet function expanded and figure typo fixe

Modelling and optimisation of the operation of a radiant warmer

This paper presents numerical calculations of the temperature field obtained for the case of a neonate placed under a radiant warmer. The results of the simulations show a very non-uniform temperature distribution on the skin of the neonate, which may cause increased evaporation leading to severe dehydration. For this reason, we propose some modifications on the geometry and operation of the radiant warmer, in order to make the temperature distribution more uniform and prevent the high temperature gradients observed on the surface of the neonate. It is concluded that placing a high conductivity blanket over the neonate and introducing additional screens along the side of the mattress, thus recovering the radiation heat escaping through the side boundaries, helped providing more uniform temperature fields.The European Union for the Marie Curie Fellowship grant awarded to the Centre for CFD, University of Leeds

Improved Gas Sensing Performance of ALD AZO 3-D Coated ZnO Nanorods

This paper reports an enhancement on the sensing performance of ZnO nanorod ethanol sensors with a new approach by utilizing nested coatings of Aluminum doped ZnO (AZO) thin films by Atomic Layer Deposition (ALD) technology. ZnO nanorods were grown by the hydrothermal method with the ZnO seed layer synthesized on Silicon wafers by ALD. To enhance the sensing performance of ZnO nanorod ethanol sensors, multiple coated AZO thin film 3-D coatings were deposited on the surface of the intrinsic ZnO nanorods by ALD.To investigate the sensing performance of the ZnO nanorods sensor for the detection of ethanol vapor, a gas sensor testing system was designed and built with a sealed reaction chamber and a temperature controller. The demonstrated sensing performance results include the sensing response comparison between ZnO nanorods before and after ALD coatings with AZO films at different temperatures and with various concentrations of input ethanol vapor. The response times and recovery times of ZnO nanorods before and after ALD coatings with AZO thin films were analyzed to investigate the sensing enhancement. The sensing response improvement peaks at 25°C room temperature with approximately 200% enhancement. However, the sensing response improvement decreases as a function of increasing operating temperature

METHODOLOGICAL CONSIDERATIONS FOR COMPARISONS OF UPPER EXTREMITY EMG BETWEEN INDIVIDUALS WITH AND WITHOUT PARAPLEGIA

This study compared normalization methods for surface electromyography (sEMG) for comparing individuals with (Para) and without (AB) paraplegia. Participants (Para, n=7, AB, n=11) performed 4 minutes of arm-cycling at several submaximal intensities, and an incremental maximal test to exhaustion, while sEMG of the right biceps brachii was recorded. This study analyzed sEMG at two intensities: rate of perceived exertion (RPE) 13 and at 60 W, with four methods of normalization: non-normalized, against a maximal voluntary contraction (MVIC), against a rate of perceived exertion (RPE) 9, and against the max test. Using submaximal exercise intensity based on RPE or power output will affect the results when comparing sEMG of Para and AB groups, regardless of which normalization method is used to inspect the data

Picosecond Laser Pulse Irradiation of Crystalline Silicon

Morphology changes introduced by picosecond laser pulses at λ = 532 nm and 355 nm in (111) and (100) silicon samples are studied by means of optical and high-voltage electron microscopy. Depending on energy fluence, orientation and wavelength, amorphous or highly defective regions may be created. From an analysis of damage thresholds and damage depth distributions it is concluded that melting and energy confinement precedes the formation of the structural changes

Systematic Improvement of Parton Showers with Effective Theory

We carry out a systematic classification and computation of next-to-leading order kinematic power corrections to the fully differential cross section in the parton shower. To do this we devise a map between ingredients in a parton shower and operators in a traditional effective field theory framework using a chain of soft-collinear effective theories. Our approach overcomes several difficulties including avoiding double counting and distinguishing approximations that are coordinate choices from true power corrections. Branching corrections can be classified as hard-scattering, that occur near the top of the shower, and jet-structure, that can occur at any point inside it. Hard-scattering corrections include matrix elements with additional hard partons, as well as power suppressed contributions to the branching for the leading jet. Jet-structure corrections require simultaneous consideration of potential 1 -> 2 and 1 -> 3 branchings. The interference structure induced by collinear terms with subleading powers remains localized in the shower.Comment: 54 pages, 24 figures, plus a few appendices. v2: included a parameter "eta" to account for energy loss, title improved, journal versio

Nanomechanical and Morphological Characterization of Tungsten Trioxide (WO3) Thin Films Grown by Atomic Layer Deposition

This study investigates the nanomechanical properties and surface morphology of tungsten oxide WO3thin films deposited on p-type Si(100) substrates using atomic layer deposition (ALD) technology with 2000 ALD deposition cycles at a growth temperature of 300°C and annealed at different temperatures. The samples were further furnace annealed at 500, 600 and 700°C for 60 min. The influence of the deposition process on the structure and properties of the WO3 films is discussed, presented and correlated to the characteristic features of the ALD technique. The results depict significant difference in the hardness and modulus measurements between the as deposited sample and the annealed ones. The hardness and modulus drop from 14 and 170 GPa for the as deposited sample to 10 and 140 GPa for the annealed ones respectively. Surface roughness was observed to increase with annealing temperature and the initially amorphous as deposited sample reached complete recrystallization and transformed into polycrystalline films as indicated by XRD

Atomic Layer Deposition of Nanolaminate Structures of Alternating PbTe and PbSe Thermoelectric Films

For this study PbTe and PbSe thin film nanolaminates have been prepared on silicon substrates with native oxide by Atomic Layer Deposition (ALD) using lead(II)bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (Pb(C11H19O2)(2), (trimethylsilyl) telluride ((Me3Si)2Te) and bis-(triethyl silyl) selane ((Et3Si)2Se) as ALD precursors for lead, tellurium and selenium. The experimental evidence revealed the ALD growth of lead telluride and lead selenide followed the Vollmer-Weber island growth mode. We found a strong dependence of the nucleation process on the temperature. In this paper, we present the optimized conditions for growing PbTe and PbSe thin film nanolaminates within the ALD process window range of 170 degrees C to 210 degrees C and discuss an early nano-scale PbTe/PbSe bilayer structure. Results of various physical characterizations techniques and analysis are reported

Broadband Dielectric Spectroscopic Detection of Ethanol: A Side-by-Side Comparison of ZnO and HKUST-1 MOFs as Sensing Media

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal-organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (\u3c100 \u3e°C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, the metrological technique avoids the inimical measurand distortions due to parasitic electrical effects inherent in the conductometric volatile organic compound detection