Planta de licuación de 1 MTPA LNG Prico en Texas, EEUU

En este proyecto se ha realizado el dimensionamiento de los equipos básicos de una planta de licuación de gas natural cuya localización es Texas, EEUU. La capacidad de la planta es de 1 MTPA y funciona mediante un proceso de licuefacción de licencia Prico. Su objetivo fundamental es servir de apoyo en las puntas de consumo de gas natural (el cual varía considerablemente según la época del año) mediante reinyección del producto en los gaseoductos en los momentos de mayor demanda o incluso mediante su transporte en camiones cisterna. El proyecto ha comprendido el análisis del proceso Prico con su diagrama de flujo, el dimensionamiento de los intercambiadores de calor (carcasa y tubos y plate-fin), selección de los equipos rotativos, simulación del proceso y dimensionamiento de tuberías, así como un pequeño estudio económico. Abstract In this project, sizing of main equipment of a natural gas liquefaction plant has been developed. The plant is located in Texas, EEUU. Plant capacity is 1 MTPA and is designed to produce LNG by using a Prico liquefaction process. The main objective of the designed plant is to support the peaks of consumption of natural gas (which varies considerably along the year) by liquefying, storing and reinjecting the natural gas in the pipelines or even using tanker trucks to take LNG to consumers. The project includes the analysis of the Prico process flow diagram, sizing of the heat exchangers (shell & tube and plate-fin), selection of rotatory equipment, process simulation and pipe sizing, and a viability analysis.

New QR Survey Methodologies to Analyze User Perception of Service Quality in Public Transport: The Experience of Madrid

Customer Satisfaction Surveys (CSS) have become an important tool for public transport planners, as improvements in the perceived quality of service lead to greater use of public transport and lower traffic pollution. Until now, Intelligent Transportation System (ITS) enhancements in public transport have traditionally included fleet management systems based on Automatic Vehicle Location (AVL) technologies, which can be used to optimize routing and scheduling, and to feed real-time information into passenger information channels. However, surveys of public transport users could also benefit from the new information technologies. As most customers carry their smartphones when traveling, Quick Response (QR) codes open up the possibility of conducting these surveys at a lower cost.This paper contributes to the limited existing literature by developing the analysis of QR codes applied to CSS in public transport and highlighting their importance in reducing the cost of data collection and processing. The added value of this research is that it provides the first assessment of a real case study in Madrid (Spain) using QR codes for this purpose. This pilot experience was part of a research project analyzing bus service quality in the same case study, so the QR code survey (155 valid questionnaires) was validated using a conventional face-to-face survey (520 valid questionnaires). The results show clearly that, after overcoming a few teething troubles, this QR code application will ultimately provide transport management with a useful tool to reduce survey costs

Examining retirement housing preferences among international retiree migrants

Housing demand models based on individual consumer’s utility function reflect preferences about the structure and lot, neighborhood, and location as related to socioeconomic characteristics of the occupants. As a growing proportion of aging residents in many countries are undertaking late life moves, their preferences will have an influence on destination housing markets. We examine the characteristics, attitudes and preferences about retirement housing among immigrant retirees currently living in traditional housing in a retirement destination in Alicante, Spain. Using results from a survey of German and British retirees living in the region, we find through logistic regression that preference for retirement housing is associated with aging and gaining access to in-home support services.

Quarter bill for Samuel Abbot signed by Steward Caleb Gannett, 1782 November 28

Printed quarter bill for Samuel Abbot (Harvard AB 1785) with sizing and punishment totals, and handwritten credits, signed by Steward Caleb Gannett.

Quarter bill for Timothy Bigelow, 1785 February 25

Printed quarter bill for Timothy Bigelow (Harvard AB 1786) with sizing and punishment totals. Handwritten text of name, date, and bill totals is faded.

Quarter bills for Stephen Moody signed by Steward Caleb Gannett, 1786-1789

Four printed quarter bills for Stephen Moody (Harvard AB 1790) with sizing and punishment totals, each signed by Steward Caleb Gannett.

Quarter bills for Daniel Marrett signed by Steward Caleb Gannett, 1786-1790

Fourteen printed quarter bills for Daniel Marrett (Harvard AB 1790) with sizing and punishment totals, signed by Steward Caleb Gannett.

Quarter bills for Nathaniel Thayer signed by Steward Caleb Gannett, 1787-1789

Four printed quarter bills for Nathaniel Thayer (Harvard AB 1789) with sizing and punishment totals, signed by Steward Caleb Gannett.

Philadelphia, Pennsylvania, Reed's map, 1774 (Raster Image) (Image 1 of 2)

This layer is a georeferenced raster image of the historic paper map entitled: Fac simile of Reed's map : to the honourable House of Representatives of the freemen of Pennsylvania this map of the city and liberties of Philadelphia with the catalogue of purchasers is humbly dedicated by their most obedient humble servant, Iohn Reed, James Smither sculp. Facsimile of a map originally published in 1774. Republished by Charles L. Warner in 1870. Scale [1:23,760]. Covers portions of Philadelphia, Pa. This layer is image 1 of 2 total images of the two sheet source map, representing the eastern portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Pennsylvania South State Plane Coordinate System NAD83 (in Feet) (Fipszone 3702). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. Cadastral map showing property boundaries, areas, lot numbers, and names of landowers. Includes features such as roads, drainage, and more. Includes inset: A ground plan of the city of Philadelphia. Also includes extensive text and index of landowners. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Philadelphia, Pennsylvania, Reed's map, 1774 (Raster Image) (Image 2 of 2)

This layer is a georeferenced raster image of the historic paper map entitled: Fac simile of Reed's map : to the honourable House of Representatives of the freemen of Pennsylvania this map of the city and liberties of Philadelphia with the catalogue of purchasers is humbly dedicated by their most obedient humble servant, Iohn Reed, James Smither sculp. Facsimile of a map originally published in 1774. Republished by Charles L. Warner in 1870. Scale [1:23,760]. Covers portions of Philadelphia, Pa. This layer is image 2 of 2 total images of the two sheet source map, representing the western portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Pennsylvania South State Plane Coordinate System NAD83 (in Feet) (Fipszone 3702). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. Cadastral map showing property boundaries, areas, lot numbers, and names of landowers. Includes features such as roads, drainage, and more. Includes inset: A ground plan of the city of Philadelphia. Also includes extensive text and index of landowners. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Burnt district of Boston, Massachusetts, 1873 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan of burnt district (by fire of Nov. 9th and 10th, 1872) : showing street improvements as adopted by Board of Street Commissioners and City Council, 1873, Thos. W. Davis, city surveyor ; presented by the Boston Safe Deposit and Trust Co. It was published in 1876. Shows street improvements, property lots, lot ownership, and square footage of lots affected by the fire of 1872. Covers area bounded by Washington St. to Oliver St., State St. to Summer St. and Atlantic Ave., Boston, Massachusetts. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

A hybrid genetic algorithm for the multi-depot vehicle routing problem

The distribution of finished products from depots to customers is a practical and challenging problem in logistics management. Better routing and scheduling decisions can result in higher level of customer satisfaction because more customers can be served in a shorter time. The distribution problem is generally formulated as the vehicle routing problem (VRP). Nevertheless, there is a rigid assumption that there is only one depot. In cases, for instance, where a logistics company has more than one depot, the VRP is not suitable. To resolve this limitation, this paper focuses on the VRP with multiple depots, or multi-depot VRP (MDVRP). The MDVRP is NP-hard, which means that an efficient algorithm for solving the problem to optimality is unavailable. To deal with the problem efficiently, two hybrid genetic algorithms (HGAs) are developed in this paper. The major difference between the HGAs is that the initial solutions are generated randomly in HGA1. The Clarke and Wright saving method and the nearest neighbor heuristic are incorporated into HGA2 for the initialization procedure. A computational study is carried out to compare the algorithms with different problem sizes. It is proved that the performance of HGA2 is superior to that of HGA1 in terms of the total delivery time.

Gas-fired radiant heaters

This dissertation covers four areas of particular interest for the successful application of radiant heating in industrial environments. In it the author tackles the problem of how to predict the thermal comfort produced both by single heaters and also systems of heaters; proposes a method for modelling the mechanisms by which heaters interact with the buildings in which they are installed, in the static and dynamic cases; explores techniques for measuring the radiation produced by heaters; and presents experiments concerned with finding the temperatures and power balances prevailing during normal operation. It is contended that, whilst the generally accepted guides for sizing and operating space heating plant were a good first approximation, there are intrinsic subtleties arising from the fact that the primary mode of heat transfer in this instance is radiative. These nuances are concerned with how best to maximise the heat transfer from the heat source to the heated object; the placement of heaters within a system; and an assessment of the various techniques and strategies involved in controlling a radiant heating system. The conclusions reached are that: if sized and controlled correctly radiant heating systems offer considerable operational advantages over other types of space heating systems in certain applications, in terms of both economy and controllability. The efficacy of radiant heating systems is affected primarily by the control strategy implemented; secondarily, by the structure of the building into which it is installed; and only marginally by all other factors.

A solar-powered reverse osmosis system for high recovery of freshwater from saline groundwater

Desalination of groundwater is essential in arid regions that are remote from both seawater and freshwater resources. Desirable features of a groundwater desalination system include a high recovery ratio, operation from a sustainable energy source such as solar, and high water output per unit of energy and land. Here we propose a new system that uses a solar-Rankine cycle to drive reverse osmosis (RO). The working fluid such as steam is expanded against a power piston that actuates a pump piston which in turn pressurises the saline water thus passing it through RO membranes. A reciprocating crank mechanism is used to equalise the forces between the two pistons. The choice of batch mode in preference to continuous flow permits maximum energy recovery and minimal concentration polarisation in the vicinity of the RO membrane. This study analyses the sizing and efficiency of the crank mechanism, quantifies energy losses in the RO separation and predicts the overall performance. For example, a system using a field of linear Fresnel collectors occupying 1000 m2 of land and raising steam at 200 °C and 15.5 bar could desalinate 350 m3/day from saline water containing 5000 ppm of sodium chloride with a recovery ratio of 0.7.

Development of an integrated reverse osmosis-greenhouse system driven by solar photovoltaic generators

The development of a system that integrates reverse osmosis (RO) with a horticultural greenhouse has been advanced through laboratory experiments. In this concept, intended for the inland desalination of brackish groundwater in dry areas, the RO concentrate will be reduced in volume by passing it through the evaporative cooling pads of the greenhouse. The system will be powered by solar photovoltaics (PV). Using a solar array simulator, we have verified that the RO can operate with varying power input and recovery rates to meet the water demands for irrigation and cooling of a greenhouse in north-west India. Cooling requires ventilation by a fan which has also been built, tested and optimised with a PV module outdoors. Results from the experiments with these two subsystems (RO and fan) are compared to theoretical predictions to reach conclusions about energy usage, sizing and cost. For example, the optimal sizing for the RO system is 0.12–1.3 m2 of PV module per m2 of membrane, depending on feed salinity. For the fan, the PV module area equals that of the fan aperture. The fan consumes <30 J of electrical energy per m3 of air moved which is 3 times less than that of standard fans. The specific energy consumption of the RO, at 1–2.3 kWh ?m-3, is comparable to that reported by others. Now that the subsystems have been verifi ed, the next step will be to integrate and test the whole system in the field.