61 research outputs found
The shoelace book: a mathematical guide to the best (and worst) ways to lace your shoes
No full textCrisscross, zigzag, bowtie, devil, angel, or star: which are the longest, the shortest, the strongest, and the weakest lacings? Pondering the mathematics of shoelaces, the author paints a vivid picture of the simple, beautiful, and surprising characterizations of the most common shoelace patterns. The mathematics involved is an attractive mix of combinatorics and elementary calculus. This book will be enjoyed by mathematically minded people for as long as there are shoes to lace. Burkard Polster is a well-known mathematical juggler, magician, origami expert, bubble-master, shoelace charmer, a
Corrupting Capitalism: Michael Ende’s Momo and “Cathedral Station”
No full textMichael Ende, the well-known author of The Neverending Story , foresaw dramatic changes in the fabric of society resulting from a turn toward neoliberal policies. One such far-reaching and dangerous change has to do with a diminishing of temporal autonomy, the ability to freely determine the use and meaning of our time. This article explores how neoliberalism is shaping our concept of time and our experience of it. In an effort to demonstrate the process and the line of reasoning behind the monetization of time, and to connect time to more qualitative considerations of the human condition, I shall demonstrate how Ende conceptualizes time as an integral part of the accumulation process of capitalism. I also discuss a fairly cryptic short story, “Cathedral Station,” that envisions “the mystery of money.” Utilizing Walter Benjamin’s critique issued in his 1921 fragment “Capitalism as Religion,” I outline Ende’s dystopian vision of the uncontested, unquestioned reign of capitalism as a religious cult. Read together, the novel and the short story offer a way of contrasting two extreme byproducts of capitalism’s colonization of time, namely what I would call an “ideology of work” and an “ideology of growth.” The first of these is a result of capitalism’s commodification of time according to liberal ideals such as choice, freedom, and self-interest. The second is a decidedly neoliberal phenomenon in that the “financialization of everything,” to use David Harvey’s phrase, results in the ever-present expectation of unlimited, exponential growth. By drawing out these two interconnected ideologies through close readings, the subtle processes of capitalism’s colonization of time are revealed
Learning From Experience: The Oaklander Approach to Teaching Child Psychotherapists
No full textAbstract
Gestalt therapy theory places great importance on the role of the client's authentic experience in the therapeutic process (Latner, 1973; Perls, Hefferline, & Goodman, 1951; Polster & Polster, 1973; Wheeler, 1991). Authentic experience is also considered central when Gestalt therapy theory is applied to educational settings (Brown, 1971; Woldt & Toman, 2005). Dr. Violet Oaklander, a prominent Gestalt-based child psychotherapist, author, and therapist teacher/mentor, places great importance on the role of authentic experience for adults in her two-week intensive summer program on how to work therapeutically with children and adolescents. The aspects and implications of her experiential approach to teaching adults are explored and analyzed in the article with emphasis placed on the ways in which her approach to adult education is both developmentally appropriate and cross culturally relevant.</jats:p
Enabling Battery-powered Train Operation: Power Forecast Model for Overhead Catenary Islands in Regional Passenger Railway
No full textThe amendment of the German Federal Climate Protection Act of 2022 defines targets to reduce greenhouse gas emissions by 65% by 2030 and 88% by 2040 compared to 1990 levels. In Germany, the transport sector accounts for 20% of CO2 equivalent emissions. While most of these emissions stem from road bound traffic, diesel vehicles are still common in rail-transport. For instance, a significant share of commuter transport services is currently achieved with diesel propelled multiple units. To reduce tailpipe emissions, these vehicles are ought to be replaced with electric multiple units. As the installation of overhead catenary along the entire track is often cost intensive and not economically viable, battery electric multiple units (BEMU) are going to be utilized in various railway networks, some of them already in operation.
A major challenge of BEMU is the limited autonomy. Common market ready vehicles may cover autonomy ranges between 80 and 200 km, while circulation plans require often considerably larger ranges of not electrified kilometers over an operational day. The limited range of BEMU can be accounted for by installing additional recharging infrastructure at selected stations or track sections, typically designed as overhead catenary islands (OCI), as they are not connected to a wider rail catenary network. The vehicles can recharge the traction battery at these OCI the same way they do under conventional overhead catenary with a pantograph mounted at the vehicle roof. This way, the vehicles can also recharge under already electrified sections. Vehicles often drive under existing electrification when regional commuter lines meet long distance connections; i.e. at the centers of larger cities.
OCI`s are usually installed on rural sides, with fewer connections and fewer passengers and, uncommonly in Europe, OCI are connected to the public electricity grid instead of the rail electricity grid. These rural electricity distribution grids are often not designed for the high-power loads occurring in the recharging of rail vehicles. Therefore, it is crucial to quantify occurring peaks and loads to equip weak grids to cope with these new challenges.
As BEMU-vehicles are just entering market (for instance, as of 02/2024 only one railway network in Germany is operating BEMU), there is little to no experience in the operation of BEMU and OCI. To gain a better understanding of the implications of these novel technologies, we developed a model to i) model vehicle energy flows, battery state of charge and power at the converter to the catenary and ii) aggregate the overall power at OCI by considering comprehensive circulation plans.
The model first links timetable data with vehicle circulation plans and adds infrastructure data such as station locations, max speed, track electrification and inclination. These inputs are run through a longitudinal simulation to calculate the traction power at wheel level. Vehicle energy flows are then modeled to calculate the power at the battery and the resulting state-of-charge of the on-board traction batteries. A geospatial sub-model is incorporated, to match the vehicle trajectories to the OCI. Vehicle recharges are aggregated with regard to the location of the corresponding OCI and the specific time of day. The aggregated curves serve as 24 hour demand profile forecasts of OCI. A sub model is set up to understand the implications of additionally installed stationary battery buffer storages to reduce peak loads on electricity grids.
The model is applied on a German regional passenger railway network where BEMU operation is ought to start operation in the upcoming years. The demand profiles are analyzed in regard to peak power, average power and 15 minutes rolling average peaks. The implications on the BEMU operation and on the power grid are analyzed and discussed. As the model utilizes real world circulation plans, the OCI power forecast model generates a power demand profile as it would appear during uninterrupted operation including trips from and to vehicle depots and other additional transfer trips as they are common in many operational plans.
The forecast model results can be useful for tendering authorities, railway operators, vehicle manufacturers and grid operators for designing recharging infrastructure and coordinating tradeoffs of dimensions on traction batteries and the density of recharging infrastructure in a railway network
D1.1 - Report concerning line and use-case based requirements
No full textThe project ‘Fuel Cell Hybrid Power Pack for Rail Applications’ was an innovation action in Horizon 2020, the most significant research programme in the European Union. Aimed at reducing the production costs of fuel cell systems in transport applications while increasing their service life to levels that can compete with conventional technologies, the programme has awarded the project entitled FCH2Rail, under Grant Agreement No. 101006633 ([1]).
FCH2Rail is a project focused on developing, building, testing, demonstrating and homologating a scalable, modular and multi-purpose Fuel Cell Hybrid PowerPack (FCHPP) applicable for different rail applications (multiple units, mainline locomotives and shunting locomotives). It is also suitable for retrofitting existing electric and diesel trains, to reach TRL7.
The purpose of Deliverable D1.1 is to analyse and gather requirements on hydrogen trains from operational and infrastructural parameters. This is done within two steps. First a high-level line analysis is performed to collect infrastructural and operational characteristics for various countries in the European Union. In the second steps, representative use-cases are identified and simulated to evaluate detailed requirements on the FCHPP.
The first part of the document (section 1) defines requirements of interests. The defined requirements are described. A methodology is described to gather and evaluate these requirements from various data sources. Section 2 describes and characterises then the data used such as timetables, digital elevation models and Open Street Map. Section 3 states the rolling stock of the investigating countries Spain, Portugal, Germany and Slovakia. The vehicles, their fleet sizes and ages are shown and
categorised by their usages. Section 4 characterises all railway services suited for the operation of hydrogen (bi-mode) trains (i.e. line-based requirements) in the investigating countries on a higher level. For each service, the requirements defined in section 1 are visualised and put in respective to each other and to vehicle
usages. The investigated countries are compared with each other. Section 5 describes a detailed investigation of various use-cases. A use-case is the specific operation of a vehicle on a certain line over a business day. A mechanical energy simulation is performed for each use-case. Simulation results are finally compared. In section 6 the findings of this study and achievable market potentials for generic FC trains are discussed
Herr Gott, dich loben alle wir Der alte Drache brennt vor Neid, Aria Nr. 3 aus der Kantate BWV 130
No full textNatural vegetation succession and sustainable reclamation
No full textNatural vegetation successional forces can be used to enhance
reclamation of drastically disturbed sites. This paper presents
a concept for land reclamation which is based on the use of
successional processes. Identification of the factors which are
precluding vegetation growth or which are limiting the
establishment of additional species is the first step in the
formulation of a sustainable reclamation program. Solutions for
overcoming these growth limiting factors are sought from those
which would occur under natural circumstances. These are then
utilized in the reclamation program. Successional reclamation
programs can revegetate sites which otherwise defy revegetation
attempts. Examples are drawn from reclamation programs
conducted by the author in western Canada.Non UBCUnreviewedOthe
Bases for Integer Generalized Splines on Graphs, an Investigation
No full textv, 20 p.Let R be a ring and G a graph whose edges are labeled by ideals of R. A vertex labeling of G by elements of the ring is called a generalized spline if for each edge, the difference of the labels of the two connected vertices lies in the edge's ideal. The author examines the algebraic structure of the set of generalized splines -it is actually an R-module- and present results of Handschy, Melnick and Reinders concerning the existence of splines where the graph is a cycle and the ring is Z. The author also summarizes more general results of Gilbert, Polster and Tymoczcko regarding existence of nontrivial splines on arbitrary graphs. They show that when working over an integral domain, the set of all splines on a graph contains a free submodule whose rank is the number of vertices. The author gives examples of their construction working over the ring of integers
Influence of Structural Modification and Chirality on the Odor Potency and Odor Quality of Thiols
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