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An equation log [10 (NA/NB)] = -0.234 + 0.874 serves to calculate NA for the 251 reported alcohol-alkane azeotropes with an average ANa of 0.050. The calculated value of NA for 1108 azeotropes involving 15 different types of azeotropes has an average ANa of 0.056. A modification of the equation gives an average ANa of 0.028 for the alcohol-alkane azeotropes and an average ANa of 0.046 for the 1108 azeotropes.

Hydrate blockage detection, remediation and removal are successfully applied in a hydrate plug incident in the GOM. A hydrate plug occurred in mid-October 2002 in the Williams Field Services (WFS) owned and operated, 36-mile long, 10- inch gas export pipeline from ChevronTexaco's Genesis Green Canyon 205 (GC 205) platform (2,600 ft water depth) to the downstream Ship Shoal 354 platform (SS 354) platform (460 ft water depth). ChevronTexaco's Flow Assurance experts, ChevronTexaco's Genesis Asset Team, and WFS team worked together to detect, locate and remediate the hydrate plug in a safe and timely fashion while ensuring personnel safety, maintaining pipeline and riser integrity and minimizing loss of production. This paper shows how a concentrated team effort and deployment of the right tools such as transient models, hydrate formation and dissociation models, can be used to predict and alleviate a flow assurance problem, such as hydrates, which can occur in deepwater oil and gas production in a subsea system. Introduction The Genesis development1 was brought on stream in February 1, 1999. In mid-October 2002, following two major shutdowns due to strong hurricanes and one for WFS planned maintenance, gas flow into the dry gas export pipeline to SS 354 was obstructed and gas delivery to shore was halted. Analysis of the measured hydraulic data prior to and during the incident showed that the obstruction in the gas pipeline was due to the presence of hydrates corresponding to low spots in the pipeline. Operations personnel in New Orleans, working in conjunction with Flow Assurance personnel in Houston were able to locate the hydrate plug via hydraulic and hydrate models based on the measured pressure, temperature and gas flow rate during the incident. Hydrate formation caused by the presence of water and natural gas components at high pressures and low temperatures in a deep-water subsea pipeline can occur during shutdown or start-up of a pipeline as was the case with Genesis. Under normal flowing conditions, dehydrated gas flows through the uninsulated Genesis export gas pipeline. Although pressures in the line were high (~1,600 psig at inlet) and temperatures as low as 42 °F in the coldest sections of the pipeline, hydrate formation was not expected due to the low water content of gas from dehydration at GC 205. However, in the presence of sufficient water, pressures and temperatures of the flowing stream in the pipeline were conducive to hydrate formation. Since water content of gas entering the pipeline was routinely monitored below hydrate formation content while flowing, hydrates should not have formed in the pipeline during steady state flow. When hydrates did form in the pipeline, many factors may have contributed to that formation such as the multiple shutdowns within a few days of each other and the added complexity in the procedures of shutting the platform down and starting it back up. During these back to back platform shut downs and start-ups, if any water had entered into the pipeline due to non-optimal dehydrator performance, the potential for hydrate formation would have been be high. Overview Genesis is ChevronTexaco's first deepwater oil and natural gas drilling and production facility located in 2,600 ft of water in the Gulf of Mexico, 150 miles south of New Orleans. The field is operated by ChevronTexaco with 56.67% working interest, and partner ExxonMobil with 38.38% working interest and PetroFina Delaware, Incorporated, with 4.95% working interest.

As energy code requirements for the thermal performance of buildings increase over time, the requirements of roofing systems are becoming more stringent. One of the requirements focuses on the minimum amount of insulation within a roofing system when it is installed in a continuous manner, entirely above the deck. However, the energy code does not clearly address the reduction of the roof system's thermal performance due to penetrations that create thermal bridges through the system. These penetrations can come in the form of fasteners used in a mechanically attached roof system or from much larger penetrations used to support rooftop equipment and accessories. It is common for roofs to contain several different types and combinations of penetrations such as roof drains, vent pipes, mechanical ducts, duct supports, mechanical equipment, roof screens, parapet bracing, ships ladders, and photovoltaic panels. Two- and three-dimensional thermal modeling will be utilized to study and quantify the impact of the thermal bridging of typical penetrations through a roof system. Results from previous studies related to the thermal impact of mechanically fastened roofs will be reviewed to gain additional insight related to this issue. A low-slope roof with a single-ply roof cover and industry standard roof details will be utilized as the basis for this evaluation. This paper will compare a variety of penetrations to a roof without any penetrations to evaluate the impact on the overall thermal performance of a roofing system. In addition, various thicknesses of insulation will be evaluated in this study.

<p>The Data Services of IRIS and the Geodetic Data Services of UNAVCO have been supporting the seismological and geodetic research communities for many decades.  Historically, these two facilities have independently managed data repositories on self-managed systems.  As part of merger activities between IRIS and UNAVCO, we have established a project to design, develop and implement a common, cloud-based platform.  Goals of this project include operational improvements such as cost-effectiveness, robustness, on-demand scalability, significant growth potential and increased adaptability for new data types.  While we expect a number of operational improvements, we anticipate a number of additional benefits for the research communities we serve.</p><p>The new platform will provide services for data queries across the internal repositories.  This will provide researchers with an easier path to discovery, and access to integratable data sets of related geophysical data.</p><p>Researchers will be able to conduct their data processing in the same, or data-proximate, cloud as the platform, taking advantage of copious and affordable computation offered by such environments.  Following the paradigm of moving the computation to the data, this will avoid the time and resource consuming need to transfer the data over the internet.  Furthermore, the adoption of cloud-optimized data containers and direct access by researchers will support efficient processing.  In cases where transferring large volumes of data are still necessary, the large capacity of cloud storage systems will allow enhanced mechanisms such as Globus for transfer, which we will be exploring.</p><p>For many users a transition of the data repositories to a new environment will be nearly seamless.  This will be made possible by implementing many of the same services already supported by the current facilities, such as the suite of FDSN web services.  The project is currently in a prototyping stage, and we anticipate having a complete design by the end of 2022.  We will report on the status of the project, anticipated directions and challenges identified so far.</p>