Moriond 2009, QCD and High Energy Interactions: Theory Summary

These proceedings provide a brief summary of the theoretical topics that were covered at Moriond QCD 2009, including non-perturbative QCD, perturbative QCD at colliders, a small component of physics beyond the standard model and heavy-ion collisions.Comment: 13 pages, 7 figures; v2 adds a reference; v3 includes small changes to tex

B−BˉB - \bar B Mixing in the HQET

We present a high statistics, quenched lattice calculation of the B-parameters $B_{B_d}$ and $B_{B_s}$, computed at lowest order in the HQET. The results were obtained using a sample of 600 quenched gauge field configurations, generated by Monte Carlo simulation at $\beta=6.0$ on a $24^{3}\times 40$ lattice. For the light quarks the SW-Clover action was used; the propagator of the lattice HQET was also tree-level improved. Our best estimate of the renormalization scale independent B-parameter is $\hat{B}_{B_d} = 1.03 \pm 0.06 \pm 0.18$. $\hat{B}_{B_d}$ has been obtained by using ``boosted'' perturbation theory to calculate the renormalization constants which relate the matrix elements of the lattice operators to the corresponding amplitudes in the continuum. Due to the large statistics, the errors in the extraction of the matrix elements of the relevant bare operators are rather small. The main systematic error, corresponding to $\pm 0.18$ in the above result, comes from the uncertainty in the evaluation of the renormalization constants, for which the one-loop corrections are rather large. The non-perturbative evaluation of these constants will help to reduce the final error. We also obtain $\hat{B}_{B_s}/\hat{B}_{B_d} = 1.01 \pm 0.01$ and $f^2_{B_s}\hat{B}_{B_s}/f^2_{B_d}\hat{B}_{B_d} = 1.38 \pm 0.07$.Comment: 15 pages, Latex, 2 figures, Small numerical errors corrected, no conclusions change

Can complex Langevin dynamics evade the sign problem?

I answer the question in the title for the relativistic Bose gas at finite chemical potential using numerical lattice simulations, complemented with analytical understanding.Comment: 7 pages, talk given at the XXVII International Symposium on Lattice Field Theory, July 26-31 2009, Peking University, Beijing, Chin

Inelastic effects in electron transport studied with wave packet propagation

A time-dependent approach is used to explore inelastic effects during electron transport through few-level systems. We study a tight-binding chain with one and two sites connected to vibrations. This simple but transparent model gives insight about inelastic effects, their meaning and the approximations currently used to treat them. Our time-dependent approach allows us to trace back the time sequence of vibrational excitation and electronic interference, the ibrationally introduced time delay and the electronic phase shift. We explore a full range of parameters going from weak to strong electron-vibration coupling, from tunneling to contact, from one-vibration description to the need of including all vibrations for a correct description of inelastic effects in transport. We explore the validity of single-site resonant models as well as its extension to more sites via molecular orbitals and the conditions under which multi-orbital, multi-vibrational descriptions cannot be simplified. We explain the physical meaning of the spectral features in the second derivative of the electron current with respect to the bias voltage. This permits us to nuance the meaning of the energy value of dips and peaks. Finally, we show that finite-band effects lead to electron back-scattering off the molecular vibrations in the regime of high-conductance, although the drop in conductance at the vibrational threshold is rather due to the rapid variation of the vibronic density of states.Comment: 38 pages, 14 figure

A Study of a Method to Predict Printing Quality of Paper by Means of Smoothness and Elongation Test Results

The object of this thesis is to investigate the use of smoothness and elongation test results as criterion for evaluating the printing quality of paper. The relationship of smoothness and printing quality has been known for many years and in all previous work it has been shown to be influential to printing quality. The relationship of elongation and printing quality has never been investigated. The experimental procedure consisted of testing the paper samples for smoothness and elongation, and determining the printing quality of the different papers with the I. G. T. Printability Tester. The results of the analysis of the experimental data can be used to indicate good or poor printing quality of paper

ANALISIS RISIKO DENGAN METODE HAZARD AND OPERABILITY STUDY (HAZOPS) DALAM PENENTUAN SAFETY INTEGRITY LEVEL (SIL) BERBASIS RISK GRAPH DAN QUANTITATIVE METHOD PADA UNIT BOILER PT X

Abstrak: Boiler beroperasi pada temperatur dan tekanan tinggi sehingga memiliki risiko ledakan. Untuk itu boiler memiliki sistem kontrol untuk mengendalikan bahaya temperatur dan tekanan tinggi menggunakan Safety Instrumented Systems (SIS). Tujuan penelitian ini untuk mengetahui Safety Integrity Level (SIL) yang menunjukan kinerja dari SIS pada boiler PT X. Penelitian ini dimulai dengan menganalisis risiko menggunakan metode hazard operability study (Hazops) untuk mendapatkan skor risiko. Hasil analisis metode Hazops menunjukkan skor risiko tertinggi pada unit boiler final superheater dan reheater sebesar 25, sedangkan skor risiko evaporator, low temperatur superheater, dan platen superheater sebesar 20. Skor tertinggi ini dikategorikan critical, sehingga risiko tidak dapat diterima dan pengendalian harus secepatnya dilakukan. Risiko terendah pada economizer dengan skor 10. Penentuan SIL menggunakan dua metode yaitu metode risk graph dan metode kuantitatif. Analisis dengan metode risk graph pada SIS unit boiler economizer menunjukkan kontrol dapat dilakukan secara manual. Sedangkan penentuan SIL pada evaporator dan low temperatur superheater menghasilkan SIL 1. Analisis risk graph pada unit boiler platen superheter, final superheater, dan reheater menghasilkan SIL 2 di semua SIS pada 3 unit ini. Penentuan SIL secara kuantitatif pada platen superheater dan final superheater menghasilkan SIL 1. Unit reheater menghasilkan SIL 2. Ini menunjukkan perlu adanya peningkatan dari SIL 1 menjadi SIL 2 pada platen superheater dan final superheater dengan mengubah desain safety instrumented function dan mengurangi waktu kalibrasi dari 1 tahun menjadi 6 bulan. Kata kunci: boiler, hazops, sil, risk graph, quantitative method Abstract: Boiler operated at high temperatures and pressures so it has a risk of explosion. Therefore, the boiler has an automatic control system to minimize the hazard of high temperatures and pressures using Safety Instrumented Systems (SIS). The purpose of this research is to determine Safety Integrity Level (SIL) which is the performance of SIS. This research begins to analyze risk using the hazard operability study method (Hazops) to get a risk score. The results of the Hazops method analysis showed the highest risk score on the final superheater and reheater boiler units of 25, while the evaporator score, the superheater low temperature, and the superheater platen were 20 categorized as critical so control must be done as soon as possible. The lowest risk on economists with a score of 10. SIL determination uses two methods are the risk graph method and the quantitative method. Analysis uses the risk graph method on the SIS boiler economizer unit shows that control can be done manually. While SIL on evaporator and low temperature superheater results SIL 1. Risk graph analysis on the superheter platen boiler unit, final superheater, and reheater produces SIL 2 in all SIS in these 3 units. Quantitative determination of SIL on the platen superheater and final superheater shows SIL 1. The reheater unit shows SIL 2. The results of the analysis indicate that there is an increase from SIL 1 to SIL 2 on the platen superheater and final superheater by changing the safety instrumented function design and reducing calibration time from 1 year to 6 months. Keywords: boiler, hazops, sil, risk graph, quantitative method