ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymerization. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

Human-induced climate change : an interdisciplinary assessment

Abstract: Bringing together many of the world’s leading experts, this volume is a comprehensive, state-of-the-art review of climate change science, impacts, mitigation, adaptation, and policy. It provides an integrated assessment of research on the key topics that underlie current controversial policy questions. The first part of the book addresses recent topics and findings related to the physical–biological earth system, including air pollution–climate interactions, climate interactions with the carbon cycle, and quantitative probability estimates of climate sensitivity and change. The next part of the book surveys estimates of the impacts of climate change for different sectors and regions, describes recent studies for individual sectors, and examines how this research might be used in the policy process. The third part examines current topics related to mitigation of greenhouse gases and explores the potential roles of various technological options that would limit greenhouse-gas emissions and enhance terrestrial carbon sinks. The last part focuses on policy design under uncertainty. Dealing with the scientific, economic, and policy questions at the forefront of the climate change issue, this book will be invaluable for graduate students, researchers, and policymakers interested in all aspects of climate change and the issues that surround it.

JPEG compression history estimation for color images

Abstract: We routinely encounter digital color images that were previously compressed using the Joint Photographic Experts Group (JPEG) standard. En route to the image's current representation, the previous JPEG compression's various settings-termed its JPEG compression history (CH)-are often discarded after the JPEG decompression step. Given a JPEG-decompressed color image, this paper aims to estimate its lost JPEG CH. We observe that the previous JPEG compression's quantization step introduces a lattice structure in the discrete cosine transform (DCT) domain. This paper proposes two approaches that exploit this structure to solve the JPEG Compression History Estimation (CHEst) problem. First, we design a statistical dictionary-based CHEst algorithm that tests the various CHs in a dictionary and selects the maximum a posteriori estimate. Second, for cases where the DCT coefficients closely conform to a 3-D parallelepiped lattice, we design a blind lattice-based CHEst algorithm. The blind algorithm exploits the fact that the JPEG CH is encoded in the nearly orthogonal bases for the 3-D lattice and employs novel lattice algorithms and recent results on nearly orthogonal lattice bases to estimate the CH. Both algorithms provide robust JPEG CHEst performance in practice. Simulations demonstrate that JPEG CHEst can be useful in JPEG recompression; the estimated CH allows us to recompress a JPEG-decompressed image with minimal distortion (large signal-to-noise-ratio) and simultaneously achieve a small file-size.

Desulfurization and Structural Transformation of Thiophene on the Pt(111) Surface

Abstract: The temperature dependence of near-edge x-ray-absorption fine-structure spectra above the C $K$ edge and S ${L}_{2,3}$ edge for thiophene (${\mathrm{C}}_{4}$${\mathrm{H}}_{4}$S) on Pt(111) reveals changes in the chemisorption geometry and the cleavage of the carbon-sulfur bond. Our results suggest the formation of a metallocycle intermediate after desulfurization with the S atom replaced by a Pt surface atom. The near-edge x-ray-absorption fine-structure results are corroborated by thermal-desorption, x-ray photoemission, and electron-energy-loss data.