World Solar Challenge September 3 update

In the leadup to the 2019 Bridgestone World Solar Challenge in Australia this October, most cars have been revealed (see my recently updated illustrated list of teams), with JU’s reveal a few days ago (see below), and Tokai’s reveal due in a few hours.

There are now 9 international teams in Australia (more than the number of local teams). Eindhoven (#40), Agoria (#8), and part of Vattenfall (#3) are driving north to Darwin, while Top Dutch (#6) have a workshop in Port Augusta (and living quarters in Quorn).


JU’s solar car Axelent (photo credit)

The chart below shows progress in submitting compulsory design documents for the race. White numbers highlight eight teams with no visible car or no visible travel plans:

  • #86 Sphuran Industries Private Limited (Dyuti) – this team is probably not a serious entry. I will eat my hat if they turn up in Darwin.
  • #63 Alfaisal Solar Car Team – recently, they have gone rather quiet, but they have a working car.
  • #89 Estidamah – they have not responded to questions. They also might not turn up, although they have obtained several greens for compulsory documents.
  • #80 Beijing Institute of Technology – they never say much, but they always turn up in the end. I don’t expect this year to be any different.
  • #4 Antakari Solar Team – they are clearly behind schedule, but they are an experienced team. They will probably turn up. (edit: they have revealed a beautiful bullet car)
  • #55 Mines Rabat Solar Team – they seem to have run out of time. Can they finish the car and raise money for air freight? I’m not sure. (edit: it seems that they will attend the Moroccan Solar Challenge instead of WSC)
  • #98 ATN Solar Car Team and #41 Australian National University  – these teams are obviously in trouble but, being Australian, they should still turn up in Darwin with a car. (edit: both teams have since revealed cars)



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World Solar Challenge late August update

In the leadup to the 2019 Bridgestone World Solar Challenge in Australia this October, most cars have been revealed (see my recently updated illustrated list of teams), and the first few international teams (#2 Michigan, #3 Vattenfall, #6 Top Dutch, #8 Agoria, and #40 Eindhoven) have arrived in Australia (see map above). Bochum (#11), Twente (#21), and Sonnenwagen Aachen (#70) are not far behind. Eindhoven (#40) are currently engaged in a slow drive north, while Top Dutch (#6) have a workshop in Port Augusta (and living quarters in Quorn).

Meanwhile, pre-race paperwork is being filled in, with Bochum (#11) and Twente (#21) almost complete. Sphuran Industries from India (#86) is not looking like a serious entrant. On a more positive note, though, Jönköping University Solar Team (#46) is revealing their car later today!


Solar car map of the Netherlands plus borderlands

Below (click to zoom) is a solar car map of the Netherlands (north, south, east, west), plus the German cities of Aachen & Bochum and the Belgian city of Leuven, which are close enough to the Dutch border to be in the map region. That’s 7 solar car teams in a very small corner of the world! (base map modified from one by Alphathon).


Exploring the moral landscape with recursive partitioning

I’ve mentioned the World Values Survey before. Lately, I’ve been taking another look at this fascinating dataset, specifically at the questions on morality. The chart below provides an analysis of responses to the question “Is abortion justifiable?” These responses ranged from 1 (“never justifiable”) to 10 (“always justifiable”). I looked at the most recent data for Australia and the United States, plus one European country (the Netherlands) and one African country (Zambia), using recursive partitioning with the rpart package of R, together with my own tree-drawing code.

Attitude data such as this is often explained using political orientation, but political orientation is itself really more of an effect than a cause. Instead, I used age, sex, marital status, education level, language spoken at home, number of children, and religion as explanatory variables, with some grouping of my own. Demographic weightings were those provided in the dataset.

For the United States (US), the overall average response was 4.8 (as at 2011, having risen from 4.0 in 1995). However, among more religious people, who attended religious services at least weekly, the average response was lower. This group was mostly, but not entirely, Christian, and the area of the box on the chart gives an approximate indication of the group’s size (according to Pew Forum, this group has been slowly shrinking in size, down to 36% in 2014). The average response was 3.0 for those in the group who also engaged in daily prayer, and 4.3 for those who did not. Among those who attended religious services less than weekly, the responses varied by education level. The average response was 4.8 for those with education up to high school; 6.9 for those with at least some tertiary education who were Buddhist (B), Hindu (H), Jewish (J), Muslim (M), or “None” (N); and 5.4 for those with at least some tertiary education who were Catholic (C), Orthodox (Or), Protestant (P), or Other (Ot).

For Australia (AU), the overall average response was 5.8 (as at 2012, having risen from 4.3 in 1981), with a pattern broadly similar to the US. Here the “more religious” category included those attending religious services at least monthly (but it was still smaller a smaller group than in the US). The average response was 2.7 for those in the group who also engaged in daily prayer, and 4.6 for those who did not. The group most supportive of abortion were those attending religious services less than monthly, with at least some tertiary education, and speaking English or a European language at home. Those speaking Non-European languages at home clustered with the religious group (and those with at least some tertiary education speaking Non-European languages at home are a growing segment of the population, increasing from 6.2% of adults in the 2011 Census to 8.3% of adults in the 2016 Census).

For the Netherlands (NL), the overall average response was 6.5 (as at 2012). Those most opposed to abortion either attended religious services at least weekly (3.2), or were Hindu or Muslim (3.3). Then came those who either attended religious services monthly (5.2), or who attended religious services less often, but were still Catholic (C), Orthodox (Or), Protestant (P), or Other (Ot), and had not completed high school (5.3). The group most supportive of abortion were those attending religious services less than monthly, with at least some tertiary education, and who were Buddhist, Jewish, or “None” (7.9).

For Zambia (ZM), opposition to abortion was strong, with an overall average response of 3.2 (as at 2007). It was highest for those whose marital status was “separated” (4.5), and lowest for those aged 28 and up whose marital status was anything else (2.8).

Of the explanatory variables I used, all except sex, age, and number of children were important in at least one country. However, sex was important for “Is prostitution justifiable?” or “Is violence against other people justifiable?” Age was important for “Is homosexuality justifiable?” or “Is sex before marriage justifiable?” Number of children was important for “Is divorce justifiable?” or “Is suicide justifiable?” For example, here is an analysis of attitudes to divorce:


New solar car teams #1: Top Dutch

Top Dutch Solar Racing  (click: ) is a new solar car team sponsored by the northern (“top”) region of the Netherlands: the provinces Groningen, Friesland, and Drenthe (see topdutch.com). This is a region with a long history and a strong environmental focus (see montage above).

The team is associated with the Hanze University of Applied Sciences, the University of Groningen, the NHL Stenden University of Applied Sciences, and local high schools. They are building a Challenger-class car for the 2019 Bridgestone World Solar Challenge. Although I wasn’t aware of it at the time, they had observers at the 2017 event, so they know what they are up against. They will be joining three other teams from the Netherlands (Nuon, Twente, and the Cruiser-class team from Eindhoven), which means that, for the first time, an all-Dutch podium becomes a possibility.

Team manager Jeroen Brattinga explains the project in this (Dutch) video. They have also been driving a test chassis around for some time.


L.E.J. Brouwer, fifty years later

Luitzen Egbertus Jan Brouwer (27 February 1881 – 2 December 1966) was a Dutch mathematician who founded intuitionism and made important contributions to topology, such as his fixed-point theorem, which states that every continuous function f mapping a compact convex set into itself has a fixed point a [i.e. f(a) = a]. A consequence of the theorem is when a crumpled sheet of paper is placed on top of (and within the boundaries of) a copy of itself, at least one point on the top sheet lies over the corresponding point on the bottom sheet.

Brouwer had a huge impact on mathematics and logic in the Netherlands, influencing people such as Arend Heyting (student), Dirk van Dalen (grandstudent), and Henk Barendregt (great-grandstudent).

The Dutch Royal Mathematical Society (Koninlijk Wiskundig Genootschap) is organising a special event marking 50 years since Brouwer’s death. The event is on 9 December in the Amsterdam Science Park. It looks to be an interesting event. Details here.


Mathematics in action: tiling the plane

In the next post of our mathematics in action series, we look at tessellations of the plane. The most familiar of these are the three regular tilings, using tiles that are regular triangles, squares, or (as below) hexagons.


Photo: Claudine Rodriguez

The great Dutch artist M. C. Escher is famous for his distorted versions of such tilings, such as this tiling on the wall of a museum in Leeuwarden:


Photo: Bouwe Brouwer

Alternatively, the regular tilings can be extended by mixing different kinds of regular polygon. Of particular interest are the eight semiregular tilings, in which the tiles all meet edge-to-edge, and each vertex is equivalent to each other vertex (i.e. each vertex can be mapped to each other vertex through rotations, reflections, translations, or glide reflections). Here is one of the eight:


Photo: “AnnekeBart”

Because of the high level of symmetry, an exhaustive list of the 11 regular and semiregular tilings can be made by considering all possible meetings of polygons at a vertex, such as these two:

    

Penrose tilings, discovered by Roger Penrose in 1974, loosen the regularity and symmetry conditions, while still using a fixed number of kinds of tile, and while still being “almost” symmetrical. In the image below, Penrose is standing on a Penrose tiling. His 1974 discovery goes to show that fairly simple mathematical truths can still be discovered today.


Photo: “Solarflare100”