552 research outputs found
Toxic Power: What the Toxics Release Inventory Tells Us About Power Plant Pollution
Examines nationwide and state electric utility data to show the quantity and nature of toxic pollutants reported by power plants, and describes the potential health damage they can cause. Suggests ways for reducing toxic power plant pollution
Kinetics and moving species during Co2Si formation by rapid thermal annealing
We have investigated the growth kinetics and identified the moving species during Co2Si formation by rapid thermal annealing (RTA). For the kinetics study, samples which consisted of a thin Co film on an evaporated Si substrate were used. To study which species moves, samples imbedded with two very thin Ta markers were employed. Upon RTA, only one silicide phase, Co2Si, was observed to grow before all Co was consumed. The square root of time dependence and the activation energy of about 2.1±0.2 eV were observed during the Co2Si formation up to 680 °C. The marker study indicated that Co is the dominant mobile species during Co2Si formation by RTA. We conclude that Co2Si grows by the same mechanisms during RTA and conventional thermal annealing
Vassiliev Invariants for Links from Chern-Simons Perturbation Theory
The general structure of the perturbative expansion of the vacuum expectation
value of a product of Wilson-loop operators is analyzed in the context of
Chern-Simons gauge theory. Wilson loops are opened into Wilson lines in order
to unravel the algebraic structure encoded in the group factors of the
perturbative series expansion. In the process a factorization theorem is proved
for Wilson lines. Wilson lines are then closed back into Wilson loops and new
link invariants of finite type are defined. Integral expressions for these
invariants are presented for the first three primitive ones of lower degree in
the case of two-component links. In addition, explicit numerical results are
obtained for all two-component links of no more than six crossings up to degree
four.Comment: 44 pages, LaTex, epsf.sty, 15 figure
Nonequilibrium quantum-impurities: from entropy production to information theory
Nonequilibrium steady-state currents, unlike their equilibrium counterparts,
continuously dissipate energy into their physical surroundings leading to
entropy production and time-reversal symmetry breaking. This letter discusses
these issues in the context of quantum impurity models driven out of
equilibrium by attaching the impurity to leads at different chemical potentials
and temperatures. We start by pointing out that entropy production is often
hidden in traditional treatments of quantum-impurity models. We then use simple
thermodynamic arguments to define the rate of entropy production. Using the
scattering framework recently developed by the authors we show that the rate of
entropy production has a simple information theoretic interpretation in terms
of the Shannon entropy and Kullback-Leibler divergence of nonequilibrium
distribution function. This allows us to show that the entropy production is
strictly positive for any nonequilibrium steady-state. We conclude by applying
these ideas to the Resonance Level Model and the Kondo model.Comment: 5 pages, 1 figure new version with minor clarification
KAJIAN PERBEDAAN CAMPURAN BERASPAL PANAS YANG MENGGUNAKAN BAHAN AGREGAT DENGAN BERAT JENIS (SPESIFIK GRAFITY) YANG BERBEDA
Berat jenis agregat dari berbagai sumber tidak akan sama, tergantung pada sifat fisik dan mekanik. Campuran beraspal panas dari berbagai sumber itu akan berbeda satu sama lain, Berat jenis akan mempengaruhi parameter-parameter pengujian Marshall berupa Stabilitas, Flow, VIM, VMA, VFB, kepadatan, (Spesifikasi Bina Marga tahun 2010 revisi 3). Penelitian ini akan mengkaji perbedaan campuran beraspal panas yang menggunakan bahan agregat dengan berat jenis (spesifik grafity) yang berbeda. Benda uji Marshall dibuat dengan menggunakan material batu pecah yang bersumber dari tiga tempat yaitu Kakaskasen Tomohon, Tateli Minahasa dan Matali Kotamobagu, dengan aspal penetrasi 60/70 ex Pertamina sebagai bahan pembentuk campuran beraspal panas. Setelah dilakukan pemeriksaan bahan selanjutnya dicari komposisi agregat yang memenuhi syarat untuk masing-masing campuran yaitu AC-WC dan dibuat campuran benda uji untuk 5 variasi kadar aspal untuk setiap sumber material. Hasil penelitian untuk ketiga material yang kadar aspalnya dibuat sama dan penambahan PC sebesar 1%, Maka nilai-nilai marshall menunjukkan angka yang berbeda, seperti berat jenis material Matali termasuk tinggi, sehingga berada di angka 2.7. pada pengujian Marshall di kadar aspal 6.5%, nilai stabilitas di dapat sebesar 2045 kg; flow = 2.70 mm; VIM = 3.53%; VMA = 17.67%; VFB = 80.10%; density =2.40 gr/cc; rasio filler = 0.85. Berat jenis material Tateli termasuk rendah, sehingga berada di angka 2.4 dan 2.3. pada pengujian Marshall di kadar aspal 6.5%, nilai stabilitas di dapat sebesar 1450 kg; flow= 3.01mm; VIM = 3.67%; VMA = 15.43%; VFB = 76.24%; density = 2.18 gr/cc; rasio filler = 1.41. Berat jenis material Kakaskasen termasuk rendah, sehingga berada di angka 2.4 dan 2.3. pada pengujian Marshall di kadar aspal 6.5%, nilai stabilitas di dapat sebesar 1535 kg, flow = 3.49mm; VIM = 4.58%; VMA=15.10%; VFB = 69.71%, density= 2.15 gr/cc; rasio filler = 1.07. Jika harga satuan pekerjaan Hotmix aspal diukur dalam satuan berat, maka dalam 1ton/m³ campuran yang dikalikan dengan harga satuan pekerjaan masih relatif menguntungkan.Hasil penelitian menunjukkan bahwa material Matali merupakan material yang memiliki nilai density terbesar yaitu kisaran 2.40 sedangkan material Tateli dan material Kakaskasen memiliki nilai density yang relatif rendah sehingga menghasilkan nilai yang hampir sama yaitu sebesar 2.18 dan 2.15. hal ini disebabkan semakin tinggi nilai berat jenis pada material maka nilai density semakin tinggi. Jika satuan pembayaran dari campuran beraspal panas diukur dari satuan berat, maka menggunakan agregat yang mempunyai berat jenis yang lebih besar relatif lebih mengguntungkan. Dari kesimpulan tersebut disarankan pada pekerjaan perkerasan jalan, jika sebaiknya menggunakan material yang berat jenis tinggi seperti material Matali Kata kunci: Besaran Marshall, Berat jenis, AC-WC, Material, Densit
Formality of the chain operad of framed little disks
We extend Tamarkin's formality of the little disk operad to the framed little
disk operad.Comment: 5 page
Renormalization Ambiguities in Chern-Simons Theory
We introduce a new family of gauge invariant regularizations of Chern-Simons
theories which generate one-loop renormalizations of the coupling constant of
the form where can take any arbitrary integer value. In
the particular case we get an explicit example of a gauge invariant
regularization which does not generate radiative corrections to the bare
coupling constant. This ambiguity in the radiative corrections to is
reminiscent of the Coste-L\"uscher results for the parity anomaly in (2+1)
fermionic effective actions.Comment: 10 pages, harvmac, no changes, 1 Postscript figure (now included
The Sum over Topologies in Three-Dimensional Euclidean Quantum Gravity
In Hawking's Euclidean path integral approach to quantum gravity, the
partition function is computed by summing contributions from all possible
topologies. The behavior such a sum can be estimated in three spacetime
dimensions in the limit of small cosmological constant. The sum over topologies
diverges for either sign of , but for dramatically different reasons:
for , the divergent behavior comes from the contributions of very
low volume, topologically complex manifolds, while for it is a
consequence of the existence of infinite sequences of relatively high volume
manifolds with converging geometries. Possible implications for
four-dimensional quantum gravity are discussed.Comment: 12 pages (LaTeX), UCD-92-1
- …