Improved liquid-level sensor for cryogenics

Liquid-level indicator, consisting of a diode heated by a resistor, allows simultaneous use of two or three of the liquids nitrogen, hydrogen, and helium. Operation depends on strong temperature-dependence of the forward resistance of a germanium diode and the difference between liquid and vapor in heat-transfer properties

Advances in travel geometry and urban modelling

Urban travel geometry is a generalization of patterns of movement in cities and regions where route configuration and prevailing traffic speeds constrain or direct movement in distinctive and repeatable patterns. In this paper we use these properties to construct time surfaces on which distance equates to the time of travel in the urban plane. Such surfaces can be two- or three-dimensional and are useful in the study of urban structure, locational analysis, transport planning and traffic management. A particular niche addressed in this paper is non-conformal time surface transformations in which speed or the cost of travel is constrained according to co-ordinate directions. It is argued that such models may be more suited to gridded and orbital-radial cities than previously used conformal transformations. After explaining the rationale behind the approach, a mathematical basis is developed and several calibrated examples are provided based on regions in the UK. The paper concludes with some examples of potential applications, and an annex provides a detailed mathematical framework

Toll optimisation on river crossings serving large cities

There is renewed interest in the private sector financing and operation of major transportation projects, in which a significant financial contribution comes from toll revenues. Tolling is ideally suited to river crossings, where the tolls are relatively easy to administer and collect. Because of their span, bridges over river estuaries are particularly expensive to build and maintain and so need to be put on a firm financial footing. Toll revenue is therefore a key consideration if such projects are to be financially viable and risk is to be minimised. There may be other issues to do with who benefits from the bridge and whether differential tolls should apply to local residents and non-resident bridge users. In addition, such bridges may be linked to wider economic objectives, such as local development and regeneration. This paper describes a model for estimating optimum bridge tolls, from both a financial and a welfare perspective and provides a case study that illustrates a range of scenarios that are of general interest

Market area analysis under orbital-radial routing with applications to the study of airport location

The study of market areas provides one indication of the economic and strategic value of a facility or attraction and is a commonly used tool in geographical and economic analysis. In this paper, we study a class of models for use in stereotypical urban regions with an associated orbital–radial network. The aim of the paper is to provide the theoretical and analytical tools needed to understand the shapes, size and markets of an attraction as a function of both its location and the speeds of radial and orbital access to competing attractions. As a result, we need to identify several hitherto unrecognised constructs such as eclipsing in which, due to proximity to a fast orbital road, one attraction can eliminate the market of another. We outline a facility location methodology in a case study, based on London, concerning access to airports serving the metropolis. Among other things, we identify inner and outer eclipsing envelopes for a new airports, which substantially narrows the area of search for an optimum location

Optimizing the benefits of urban road user charging

Traffic congestion is a feature of most modern cities but attempts to control it or limit its effects have met with only modest success. There is significant and continuing interest in the concept of charging city vehicle users, although apart from the use of parking charges actual operational schemes are few and far between. In this paper we compare three alternative charging policies using a simplified model of travel demand and supply, which we combine with cost benefit techniques. The charging policies are area-based charging in which users pay to locate in or enter an area, terminal-charging based on supplementary parking fees in residential and non-residential locations and distance-based charging which is a charge related to how far users travel. The model allows for behavioural effects resulting from trip diversion and demand suppression, as well as capacity restraint (speed-flow feedback effects based on limited route capacity). In the case study we parameterize the model using data and geographical dimensions based on London. We show that area based charging delivers the least benefits whilst a hybrid policy based on terminal and distance based charges delivers the most. Because it is of topical interest we compare our results and predictions with the Mayor’s strategy for London, which is an area-based scheme. We conclude that the revenue generated using a hybrid policy would be as great as for an area based scheme whilst at the same time delivering substantially greater benefits to road users in terms of travel time and other savings

ELDER LAW—MY LIFE, MY CHOICE

As the most recent past president of the National Academy of Elder Law Attorneys (NAELA) I have been involved in elder law for over thirty years, even before there was a sub-practice of estate planning called elder law. In fact, for estate planning, I recall when the primary document a client needed was a will. The required document has expanded and now includes a will, health proxy, power of attorney, a POLST form (Physician’s Order for Life Sustaining Treatment), sometimes a living will, and other various documents a client may desire, such as a cremation order, a pre-arranged burial, and the like. Many years ago, it was also the norm that many wished to be kept alive by machines, or did not take a stand as to their preference, with many families refusing to talk about it. It was also the norm that most people were buried and not cremated. Times have changed, and the pendulum has swung the other way in many cases. I remember how my mother was ill for many years, and it was determined that all measures would be taken to keep her alive, even at the end of her life when there was absolutely no chance of recovery