omenti

how to get 1000 miles per gallon

The impact of discovery and invention on society is usually unknown for years and sometimes decades and most have little impact, but a handful have led to fundamental change.  Some; the electric grid, safety elevator, air conditioning, automobile, airplane, electric water pump - to make a partial list - have brought about change that can easily be observed from low Earth orbit. 

The automobile is an interesting case.  The first real expansion of a technology that had been evolving for nearly a century began around WWI, but was limited by high costs and an undeveloped road and support infrastructure.  This began to change dramatically in the twenties and by the end of WWII most families could afford to own and operate at least a used car and the expansion of roads had reached a point where most people could easily travel between where they lived, worked, shopped and played.  

Most people justify about an hour's worth of daily commuting two and from work.  The automobile had increased the average commute distance from a few miles to something ten to twenty times greater.  The range of the average person was now greater than the size of most towns.  Cheap land and new houses in the fifties and sixties created suburbs around most cities.

At this point something around one and a half percent of the lower 48 states are covered with asphalt and concrete surfaces devoted to transportation.  Some negative aspects of burning hydrocarbons are threatening the environment, petroleum is becoming more expensive with the trend likely to continue,  and the cost of operating a car is about sixteen percent of the average families total cost of living - only housing is greater.  Congestion in many areas caused a lot of daydreaming about how to get around the traffic jams that began to appear around the major cities.  Fixes like personal helicopters and monorails were proposed in the futurist magazines of the day, but no real solutions have been implemented here.

At some point you have to ask the question “how efficient is our transportation system?” Probing a bit consider a bit more than forty percent of trips in the US are under three miles long, a third are under two miles, and a fifth are under a mile.  Cars seem ill-matched to journeys of this length, but for anything over a mile walking is probably going to be too slow and point to point public transit in most parts of the country is non-existent. 

Something like a bicycle makes a lot of sense for short trips assuming a few social problems can be solved.

It turns out this is how we can get to one thousand miles per gallon - so as promised in a recent post ...

Energy and power (power is just the energy you use divided by the time it takes to use it) have any number of units, but to physics energy is just energy.  It can’t be created or destroyed - just moved from one from to another.  If you are riding a bike the chain is something like fusion in the Sun producing light that travels to Earth and is converted into food by photosynthesis.  We eat plants directly or animals that eat plants, but basically we’re solar powered.  The same is true for a car - photosynthesis creates biomass that is stored and heated for a long time underground to produce petroleum.

I won’t go into any depth, but photosynthesis is very inefficient - usually under one percent of the energy falling on a green plant is transformed into stored chemical energy (food).  Fortunately the area under cultivation on our little planet is large enough to deal with our current population.  The process of making petroleum is even more inefficient, but it is done over millions of years which has given us enough for the past hundred years.  Unfortunately the creation of hydrocarbon fossil fuels is glacially slow.  We are currently burning them at ten to one hundred thousands times as fast as they are being created, so they are non-renewable and as such have some other nasty properties.

Nasty properties aside, gasoline and diesel fuel - liquid hydrocarbons - are excellent energy stores.  They are reasonably safe and easy to handle, relatively inexpensive (that is changing), and have a high energy density.  There are sound physical reasons why their discovery and use proved to be revolutionary. Without liquid hydrocarbons the development of the automobile would have been radically different and we are only now developing technologies that allow for ballpark similar performance.

To look at how many effective miles per gallon a person can get on a bike we need to know something about the fuel being burned and how much energy it takes to move the bike and rider over a known distance. 

Properly measuring a bike rider isn’t trivial.   You can look up carefully measured figures and make some adjustments for an approximation or you can do the measurements yourself.  Having access to a low speed wind tunnel and some serious measurement kit comes in handy.

I’ve done this for Colleen.  Riding in a comfortable upright position her tall frame isn’t exactly aerodynamic, but remember that the power needed to cut through the air goes up as the cube of the speed - at slow speeds being aerodynamically “dirty” isn’t a big thing.  If she wanted to decrease her drag, she could bend over to present a bit less surface area.

(I'll use a tiny bit of high school physics - some wrote to complain about the bit of math in a recent post, so I'll highlight this section in blue ..  skip over it if you like)

At 22.5 kilometers per hour she needs about 80.6 kilojoules to cruise along for a kilometer.¹  In units more people may recognize this is about 14 miles per hour and 31 food Calories per mile.  She is burning something like 434 Calories over her basic needs to cycle for an hour.

It is interesting to calculate the power she is getting from the metabolism of her food at this steady pace.  In an hour she requires about 1814 kilojoules of energy, so dividing by the seconds in an hour we get a bit more than 500 watts. Not all this food energy is being converted into useful mechanical work.  It turns out many of the muscle movements we make have efficiencies around twenty percent (some are much lower, others a bit higher - if your exercise equipment reports Calories burned, it is probably integrating power over time and multiplying by about 5).  Colleen happens to be a trained athlete with wonderfully smooth motions and is a bit over twenty percent efficient on a bike.

In other words she is delivering about 100 watts of power to the crank.

One hundred watts is an interesting result for a human.  An average person might eat about 2000 Calories per day.  To make the arithmetic a bit easier assume it is 2064 Calories per day. Converting to watt-hours we get 2400 watt-hours per day.  Divide by 24 hours in a day to find the average power- an average person gets about one hundred watts from her metabolism. 

Much of this - around eighty percent - is given off as heat and you can warm a cold room by having a few dozen good friends over for a party.

You can approximate the power requirement of a person as being the same as that of a 100 watt light bulb.

Increasing physical effort requires more energy.  Experimenters a few hundred years ago found an average man in good physical shape can produce about one hundred watts of power, over and above his basic needs, for an eight to ten hour period.  Farm hands doing mechanical work can eat a lot of food.  So do athletes, When Colleen was in training she required five to six thousand Calories per day and remained thin. (note - her basic needs are somewhat above 100 watts as her body isn't exactly average)

A bit of arithmetic shows 30 miles per gallon of gasoline is about 2750 kilojoules per kilometer.  The car uses about 34.1 times the energy Colleen does to travel the same distance.  

Colleen is getting close to 1025 miles per gallon - if she is drinking a vegetable oil.  That doesn’t work for her so you can figure out what she gets on a gallon of Ben & Jerry’s if you like.  

You can probably get a similar result and there are tricks, aerodynamic and otherwise, to improve it.

But a thousand miles per gallon is an impressive figure.  A bike rolls easily, has a very efficient transmission, is much lighter than the rider and doesn’t have a lot of wind resistance at low speeds.  At normal cruising speeds it is one of the most efficient ways for a person to get around (about three times as efficient as walking).  A three mile trip requires less than fifteen minutes which may be short enough to be practical for many of us.  In theory bikes could be used for about forty percent of trips in the US .. but only in theory.

The problem is making bikes practical.  I’ve spent a good deal of time on the problem for some clients as well as my own curiosity and it turns out to be surprisingly rich.  Bikes need to be perceived as “safe enough” which makes demands on roadways and motorists.  The bike needs to be available when you need it.  It must be socially acceptable to ride and so on...

In the mid seventies a few Northern European countries took very different paths from the US and each other to reduce car use and increase “active” transportation (biking and walking).  Their solutions vary and are very much a systems approach, but cycling has become socially acceptable in these and participation is extremely high by American standards (some cities see more than half of trips under five kilometers being taken on foot or bikes).  

Some of the problems caused by cars are being reduced.  There are lower demands on the area required for parking and roads, noise and air pollution has dropped, the average family outlay for transportation is lower than in the US (even though gasoline is regularly over $9 a gallon now), and there is a correlation with improved health.  

Improved health may be the greatest benefit and it was not predicted.  It turns out people seem to require at least a half hour of aerobic exercise per day to stay healthy - some suggest the number is more like an hour.  Children require more.  Americans have become extremely sedentary and often find it difficult to find time or motivation for exercise.  Cycling is excellent exercise and a visit to Amsterdam or Copenhagen shows a population with much less obesity than in the US.  Jheri, a friend in Copenhagen, notes Danish women have the best butts and legs in the world and it is all from biking...

This just scratches the surface - make a comment or send an email if you are interested in going deeper.  How these countries evolved and met obstacles is fascinating.  Matching transportation to time and distance in the US is not as optimized and moving towards something better may well be socially impossible, but interesting things are happening in a few cities.

On the longer term there is the a new challenge of what a car is and how the landscape and people will change with it.  Megacity cars are likely to be a radical departure from what we know today.  It will be interesting to see if they come in time to change the landscape of China, India and countries that are only now emerging economically.

Some city and megacity solutions have been tried and failed as the social impact was not considered.  The Segway is an interesting case.  Imagine taking a light weight low speed vehicle and putting an electric motor on it, the intention being to increase the range of walking by a factor of three or four.  After all - human muscles turn energy into motion at about twenty percent efficiency, but a small electric motor can exceed eighty percent.  

In theory it would be a nice way to get around a city, but in practice the user experience leaves much to be desired.  They are too bulky and heavy to easily move around wherever you go, they are expensive, they are too fast for safe integration with pedestrian lanes and too slow for normal roadways and so on.  Many of these issues can be made for bicycles, but the Segway has its own some set that need to be addressed.  But perhaps most important is something an anthropologist friend said to me the day the Segway was announced:

people will never go for them as the riding posture makes you look stupid

She nailed it (I've come to consult with and trust anthropologists for many issues associated with the acceptance of new technologies).  But it raises the question of why cars are often viewed as objects of desire - often going beyond their utilitarian nature. How and when did the car become romanticized?

The question is clearly complex but there are fascinating hints.  Studying the history of advertising, one comes across references to Ned Jordan - a reporter who became involved in the auto industry forming the Jordan Motor Car Company in Cleveland in 1918.

Folklore has it that he saw a beautiful woman racing her horse by the train on a trip through Wyoming. He asked the conductor where they were and heard: Oh, somewhere west of Laramie. He penned an ad for the Jordan Playboy which was published in The Saturday Evening Post. I seen it cited as a watershed moment for associating a product with romance rather than the product itself.

... the text of the ad (if it is difficult to read)

Somewhere west of Laramie there’s a broncho-busting, steer-roping girl who knows what I’m talking about.

 

She can tell what a sassy pony, that’s a cross between greased lightning and the place where it hits, can do with eleven hundred pounds of steel and action when he’s going high, wide and handsome.

The truth is--the Playboy was built for her.

Built for the lass whose face is brown with the sun when the day is done of revel and romp and race.

She loves the cross of the wild and the tame.

There’s a savor of links about that car--of laughter and lilt and light--a hint of old loves--and saddle and quirt.  It’s a brawny thing--yet a graceful thing for the sweep o’ the Avenue.

Step into the Playboy when the hour grows dull with things gone dead and stale.

Then start for the land of real living with the spirit of the lass who rides, lean and rangy, into the red horizon of a Wyoming twilight.

The copy and illustration are in stark contrast with other ads of the period.

 

And that, Virginia, is how they sell SUVs... (and everything else)

 

In Copenhagen and a few other cities there are efforts to show biking commuting as normal, cool, and even sexy - anything but pure recreation and sport.  Riders in street clothing rather than lycra on mostly non-exotic bikes and an upright riding position. Safety is built into the behavior of car drivers - for example when a Danish or Dutch driver opens a car door she is taught to do it with her right hand.  This forces her to swivel her head and watch for close bike traffic so she won't accidentally "door" someone.  There are dozens of little differences like this that are part of the culture.

It would be fascinating to understand the difference in attitudes and towards different types of transportation as a function of country and culture.

__________

¹ Approximations for calculating bicycle energy use range from about 1 to 1.6 kJ/(km-kg) and depend on bike speed, terrain and traffic, assumptions of the rider's efficiency and cadence, assumptions about the bike's efficiency, and aerodynamics. Most of the measurements have been conducted at slightly higher speeds and some have assumptions about normal use (how many starts and stops per hour) built-in.  While Colleen's figure presents a relatively large surface area due to her height and riding position;  the speed is somewhat lower, the tires are low resistance, the terrain flat and the measurement is at a constant speed. She also happens to be an athlete with a smooth and efficient motion.

Walking is generally around 4 kJ/(kg-km) at optimal cadence.  Cycling and walking are both very sensitive to cadence and surprisingly, long legs are not an advantage and in the case of walking are as important as many assume in determining optimal walking speed.  Efficiency drops dramatically if you are off cadence on a bike and are off optimal speed walking.

The most efficient swimming strokes require about 17 kJ/(kg-km) - distance swimming requires a lot of energy.

 If you prefer English units multiply kJ/(km-kg) by 0.173 to convert to Calories/(mile-pound)

 

 

cartographers of passions

For the longest time I didn't understand fashion.  Apparel was apparel and struck me as something that is by design mostly functional.   This lack of understanding translated into my own fashion sense.  I'm semi-famously informal rarely going beyond jeans and tshirts although these days my tees come from places like Theadless and a few are of my own design.

My habit of trying to learn about the passions of others by working with them on their projects has resulted in a much richer and broader education than I had anticipated.  Sometimes there is serendipity crackling in the air - serendipity that sometimes I recognize and act on... 

One of the more unusual projects was a helping a startup fashion magazine.  There were only four people and they had no idea how to network their computers.  I volunteered to get that piece working for them, but visiting their office was much more exotic than traveling overseas - these were enormously interesting and curious people who were doing things I had not imagined.   I started helping with a few other things - something very easy to find in any startup -  and found I was a bit better with Photoshop and Quark than they were.  I kept coming in one day a week and ultimately became their unpaid digital art editor.  Such an excellent vacation from my real work and such an education.  

It led to some interesting connections to the fashion world.  Eventually I came to recognize the difference between fashion and apparel and, more importantly, what might motivate people to do fashion.   Eventually these connections helped me notice street fashion - the diametric opposite of how I originally perceived the process of fashion.  I was away from it for several years, but recently thinking about this and some aspects of social media has led to some fascinating and rich threads about potential new frameworks for change in a massive industry.   It is exciting and feels like the music industry began to feel in the mid 90s.

When you start wandering about a new moonscape it is important to find a good cartographer.  

I had caught glimpses of him on his bicycle cruising the streets of Manhattan long before bikes became common in the city.  A thin elderly figure carrying a camera and sometimes stopping for a photograph.  At the time I had no idea that this was Bill Cunningham - one of fashion's important cartographers.  Perhaps the first serious cartographer of street fashion and still, even at 82, vital and important.

He deeply understands why some dress themselves in ephemeral art forms to make statements to themselves, their friends and complete strangers.  Reading and watching his pieces and beginning to take note of what was unfolding on the streets of New York City finally caused me to recognize the difference between fashion and apparel and that it can be a rich form of non-verbal communication.  

He must be excited these days as the bit of the world he loves is seeing an explosion of change at the grassroot level.  Blogs like The Sartoralist are communicating this change as are his own pieces in the fashion section of The New York Times. 

What is "in" and who sets style is not really in the hands of the designers and magazines, but it is more ephemeral and is set by those who wear are wearing it.  He caused me realize there are several feedback mechanisms and started me thinking about what this means with respect to mass customization and co-design in fashion and apparel.  This line of questioning leads to deeper questions and more interesting thoughts.  As a clumsy explorer of moonscapes you can't ask for more.

There is an excellent new movie about him - Bill Cunningham New York - that is making its way around the art film theater circuit. Check it out if you want to understand this bit of popular culture a bit better.

 

 

how much power do you need to go fast?

There is a compelling reason why the old 55 mph speed limit made sense if conservation was a goal.  The power required to move something through a fluid (air for example) increases as the cube of the velocity.  At slow speeds the power required to move may be dominated by other effects and, in cars, there are several complicating factors that need to be considered, but once you are past a certain velocity, air resistance is the major force to overcome.

It sometimes surprises people to learn the power requirement is proportional to the cube of velocity - in fact if you ask a lot of college educated people (I have) they'll guess it should go as the square.  They are probably confusing energy with power.  Power is simply the rate at which energy is "used".  So if you have a gallon of gasoline you can get a lot of power by burning it quickly in your engine with the throttle wide open or you can produce lower levels of power and consume it at a miserly rate.

Here is a simple physical explanation of why power goes as the cube.  Consider something moving through the air that presents an area to the air.  You can approximate the amount of energy being transferred to the air in some time by calculating the mass of the air moved aside in that time.  Now calculate the kinetic energy (rho is the density of the air, so the mass is just the volume of the shape traced out in time t, and the velocity is the velocity the object is traveling relative to the air) and divide by t to get the power.  

Simple and sweet...

It turns out bikes at normal cruising speeds - say about 10 to 14 mph - are in a region where most people can develop enough power to move easily, but increasing the speed to 20 mph requires serious effort.  Changing the effective surface area of the bike is a way to deal with the challenge, which is why you bend down into a more aerodynamic shape.  Most cars begin to see serious power requirements for moving air aside at around 40 or 45 mph. 

more on this topic later - we'll talk about how you can get the equivalent of 1000 miles per gallon on a bike and even more on an e-bike. 

 

(I'm just talking about a cross section of air here.  If you move a body through the air its shape is important and described by C_d - a coefficient of drag.  The area in the equation becomes C_d * cross section area of the object)

 

 

on model building

I spend a lot of time trying to think about the basics of a problem as opposed to jumping into the middle of an existing framework and turning the crank.  Basic assumptions of existing framework are often not appropriate, frequently leading to fuzzy thinking and wrong result.

Starting with the basics usually involves simple modeling and a lot of playfulness. Playfulness is fundamentally important as it allows you to sort through ideas and learning from mistakes and bad paths with no real penalty.  Building this spirit into a project into a team that is starting down a new path is non-trivial and incredibly important.  

I spend a lot of time working on projects associated with energy and find it astonishing how many companies have teams where the participants lack an understanding of simple basics like the difference between energy and power, let alone a feeling for the problem at hand.  This is even more important in problems that introduce serious complexity.  A great example is how social and technical issues mix as computation and networking interact directly with our lives.  Multi-disciplinary approaches are necessary and the core thinking needs to reflect this very early on.  The needs of the world have moved well beyond simple engineering.  

As it happens physics is an incredibly playful sport.  It is concerned with understanding fundamentals and approaching new problems involves observation and more than a little model building.  It is important to find good and bad paths at this point and that will inform work as you go on as well as build your experience.  Much of this is done in collaboration and that is often a delightful experience.

Dick Feynman was a master of the approach and crisply summed up why people do physics - the same can be said for other disciplines where passion and curiosity are motivators:

 

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

Sanjoy Mahajan gives a simple example of this way of thinking applied to a simple problem at a recent Caltech TED^x.  Sorting these things out for yourself and building a model that gives a ballpark result is much more important than looking a formula up in a book..

 

This approach is certainly not unique to physics - it is core to all of the sciences and can easily be extended to other disciplines as well as your own recreation.  Probably most significantly, and what has become very important to me, is that the basic approach can be applied to extremely cross disciplinary projects.  The basics of a problem are not necessarily confined to the artificial boundaries of single disciplines. 

A delightful side effect of working on richly multi-disciplinary projects is you learn a lot that, at first glance, might seem orthogonal to your background.  This is a good thing.  While you may not become a subject matter expert in the areas of the other folks in your collaboration, you will develop a deeper sense of their way of thinking and that adds greatly to your own tools.  

When I started out in physics I double majored in physics and math and didn't see much use for anything else.  I needed the basics - it turns out a Ph.D. in physics is just a starting point for the field where you can begin your real education.  But it turned out to form way of thinking that allows a bit of insight into diverse areas when you find great people and a bridge to communicate over disciplinary boundaries.

Over the years I've been lucky enough to have become deeply involved in perception (particularly sight and sound), astrophysics, music, art, human computer interaction, anthropology, more electrical and mechanical engineering than I would care to admit, computer science, geology, natural language, sports science, film making, anthropometrics, and even fashion.  Over time you find yourself learning to listen to others and hopefully share a bit with them.   

I'm sure this is true for many others.  Education can easily last a lifetime.  

 

working on a personal change and the necessary information flow

Last January I came to the conclusion that I had to lose some weight.  At a basic level the process should be simple - simply decrease your energy intake to some level below your energy expenditure and maintain the process.  In reality it is a complex and fascinating subject.  I found I have to balance exercise with my diet and also learned some techniques to fight food cravings.  

Much has been written on the subject and a lot of the information is folklore and poppycock with some being downright dangerous. Sorting through the science, even though I'm not a specialist, turned out to be very useful - at least I know where to find good review papers and have a firm understanding of statistics and the language of scientific papers and can judge which work stands up over time.

Designing the monitoring component is another challenge that many probably gloss over.  How do you measure your energy needs, energy spent exercising and energy in food as well as how it is metabolized?  All of these are subject to error, so what are your error bars and how do you adjust for them? And what is your information collection and processing system?  Do you trust your own numbers and how do you check the results?  This turned out to be critical as experts note successful weight loss that is healthy and maintainable should be done at a slow rate, so you are faced with a signal to noise problem. 

In short it is an excellent example of a problem where a good deal of information is available, but it is generally too difficult to have perfect information.   Lacking the monitoring facilities of an Olympic training camp how do you proceed?

I've spent a minimum of fifty hours reading medical and human physiology journals and have talked to a few of the experts along the way.  Fascinating and an excellent by-product of the effort.  You quickly learn why most fad diets work in the short term, but are rubbish over time.

My path is complicated a bit by the fact that I'm a lacto-vegetarian (I refuse to give up good chocolate and ice cream).  Keeping track of protein intake where the type of protein is important is a big deal if you want to stay healthy.  

Most of you probably are good at managing your weight or have your own system for weight loss.  Here is what I'm doing if you are interested in this sort of thing.  Understanding the information flow as well as getting motivation from people you respect are critical components.  Oddly enough sms messaging turned out to be an important component.

 I was able to accurately project my weight on the Fourth of July almost to the pound (well within my measurement error bar) by the time I was a month into my diet at the end of January.  The information flow and how I deal with it at the physical level turned out to be good enough.

Currently I'm doing a series of small experiments looking at my protein intake as a function of the time of day.  I'm testing a hypothesis that changing the protein content of my breakfast will leave me less hungry later in the day.  I noticed that I seemed to be eating a lower amount of total calories when my breakfasts were protein rich, but needed to come up with a controlled experiment.

A nifty little project that has sparked a bit of learning.  It is interesting to note that many of us carry pocket devices that might manage this sort of information flow a bit more seamlessly and I suspect a business or three lurks in doing it well.  But that is all gimmickry without resolve on the part of the person who has to eat and exercise accordingly.  Once someone has the resolve these tools can be very important, but until that point they are likely to fail.  

I also feel it is a mistake to ignore the social component.  In my case that is help and mentoring from an exercise expert friend and cheerleading from another friend.  There was some serendipity and thought involved in these selections and I'm almost certain I wouldn't have had the success I've had without them.

__________________

A side-note.  There is quite of bit of talk about the process by which data is turned into information, information into knowledge, and finally knowledge into wisdom.  I tend to ignore that - it can be a useful model if everyone is working in the same context and agrees on definitions, but in practice I find that rarely happens and it artificially elevates "data" in my mind.   In physics it is all just information so you may notice that bias.

 

 

night walking

As a teenager I was a fairly active amateur astronomer. One feature of the hobby for most of us is that the nights are frequently cloudy (most of us means people who don't live in the Southwest). I found one way to make use of the time was learn to walk with night adapted eyesight.

Nightwalking can be very beautiful. Very subtle things like glow worms (there were many of these at Stony Brook) and other luminescent objects from decay become prominent. You find yourself using your eyes in a way very different from its normal high illumination mode.

First some basics. The eye has photoreceptors called rods and cones -- cones are used for color vision and come in three flavors for most people. Rods are much more sensitive to light than cones (on average from 100 to 10,000 times as sensitive depending on the wavelength of incident light - average improvement, correcting for the number of receptors and receptor area is generally a few thousand times -- about what a good night vision scope achieves) and are not directly associated with color vision.

The trick is to find a very dark area and let your eyes become accustomed to it - generally about a half hour is required. I find averted vision best and, at least in my case, some areas of the eye seem more sensitive than others. Do some experimentation to learn what works best for you. I also find relaxing the gaze seems to help - don't try to consciously focus.

When you are fully adapted and relaxed you will find the eyes in a hunting mode ... in such conditions the eye is mechanically hunting for bright areas (the term for this is saccades and I tend to do it too much - when I take field of vision tests I find it very difficult to focus on a fixed target).

You want to make sure you are in a fairly smooth and/or well known area as you don't want to fall and injure yourself. I've found looking up at the sky can be an amazing experience if you try this on a very clear moonless night. Any moon on a clear night will be overpowering.

We generally talk about the amazing performance of animals - the wonderful eyesight of raptors and owls for example. But it turns out your own equipment is wonderful and with a few simple hacks you can explore capabilities that you probably didn't realize you had.

This is a fun result and science is driven by curiosity and play ..  but I also worry about energy and light is nothing but tiny particles of pure energy - photons.  We have an enormous fusion reactor that sits about five hundred light seconds away from us and fires a mind numbing number of photons every second to basically support all life and numerous physical processes on Earth.  Our little planet is covered by living photosynthetic biomass that is largely contained in a  layer ten meters about the ground and ten meters beneath the water.  It is inefficient, but life depends on it.

The energy that rains down on the Earth and that which has been stored will be the subject of many future posts.  Perhaps it will illuminate possibilities as well as limits and there is more than enough sunlight to power it.

 

clothing and mass customization

For an early post I'll touch on something that is a nice intersection of technology and sociology and anthropology...

 

fashion

No one has successfully accused me of being fashionable, but I'm interested in apparel and fashion for a variety of reasons.  

In the mid 90s I found myself consulting for an Army project designed to lead to better fitting uniforms.  It turns out sizing is an artifact of mass production that is anything but perfect.  It would be nice to create individual made to measure uniforms, but to mass produce them. Our approach was to build a fast body scanner that created a 3d model of a person that was then used to create a custom two dimension digital pattern.  This pattern would be used to drive automated cutting machines and the result would be sewed together (the last step probably by people). 

The military scanned a large number of soldiers and created an excellent anthropometric database.  For a variety of reasons the idea of using scanners for measurement never caught on, but several firms have experimented with the idea of practical paths to semi mass produced made to measure clothing.

I mostly forgot about this work until a few years ago when a very tall young woman became a friend of the family.  Colleen's height is something more than five standard deviations out from the female mean*.  The practical result is many manufactured items that need to fit don't.  Watching her frustration with mass produced items started me down the path of thinking about the problem again.  In another blog I discuss the general problem in two posts.

There are several interesting possible apparel industry disruptions.  Not only is better fit possible along with some customization, but the idea of what a design is becomes more fluid.  A curious thing about practical design is that copyright doesn't apply - at least not in the US and functionally not in the EU.  One reason the fashion industry has survived in its current form is fashion is dynamic and the time to manufacture has traditionally been long.  This is changing and there is some worry in the industry - shades of another industry that obsesses about copyright.

More important is the idea that design might be distributed and design mashups are possible.  This begins with customization, but it can go much beyond that.  Few of us are Jean Paul Gaultiers, but there are thousands of great street fashion designers who can modify existing designs into something that you might find more to your taste.  At some level you can also participate - perhaps choosing to customize from a safe palate of choices.

This may not happen with traditional labels, although there are models where they might participate.  It also has the ability to break the current byzantine and inefficient distribution and sales model.  You might select a pattern from a great designer and modify it yourself or use the modifications of others.  It may be possible for you to specify materials as well as the manufacturer and the resulting garment would be shipped directly to you.

The technology and business models haven't emerged yet, but the industry is huge (larger than entertainment and sports) and massive change seems likely as there is need for something better - perhaps starting with fit.

Currently the social component of fashion and design fascinates me.  This wasn't on my screen fifteen years ago, but it may be a significant driver of the disruptions that may confront the industry.  Those with serious platforms - Amazon, Facebook, Apple, Google and a few others - may be in an interesting position to participate.  It is also possible that new players might emerge.

These days many people are interested in 3d printing.  A very neat technology  that has completely changed prototyping,  but there are serious scaling and material issues for final products that move this well beyond the current time horizon.  I'll have more to say on mass customization in the future and particularly the low hanging fruit of apparel - I generally refer to mass customization of apparel as two plus epsilon dimension mass customization.   stay tuned.

 

I spend a lot of time talking with and observing people in their twenties - a time of life when there is considerable experimentation and it happens to be the group where change often emerges.  A friend I consult with is Jheri - another difficult to fit young woman in her mid twenties who lives in Copenhagen. Our conversations caused her to write a piece on the history of sizing and she has graciously allowed me to quote it here.  It was originally targeted at difficult to fit women to provide a bit of background on why the current fashion industry can't help, but it also shows why even average people can have a difficult time with fit.

so thank you Jheri!

I’m curious about fashion and have spent a bit of time studying the industry. There are basically three ways clothing is made: ready to wear, made to measure and bespoke.  

 

Most clothing is ready to wear.  A design is made and turned into a pattern which can be made larger and smaller.  It is up the the manufacturer to define the "fit" to a given size.  In fact the concept of size is quite arbitrary.  In North America the standard size, which turns out to be very different from the average size, is a size 8.  The designs are made into patterns that will fit a size 8 fit model very well and then they are adjusted incrementally up and down to make other sizes.  Adjustments are made for talls and petites and a different type of sizing usually happens around size 14 or so.  A brand may have different lines each with their own fit.  So even if you are a perfect size 8 fit model for one line another line from the same manufacturer may have a very different fit. 

 

The problem is women are curvy and the shape of our curves vary a lot.  For me I am very flat on top, but I have a nice curve from my waist to my hips.  The length and shape of that curve can vary a lot as well as how big my butt is or what shape it is and a hundred other things.  We don't need perfectly fitting clothing, but the specification of what a size 8 is only gets you in the ballpark.

 

Average sized women can shop and try on different pieces of clothing until something fits.  Even there they don't get exactly what they might like.  A friend of mine is an 8 and maybe about 5'5, which is average height for a woman. She tells me about half of the clothing she tries are terrible fits and she knows what lines are likely to fit her shape.  But there are so many clothes that she can usually find something she likes and sometimes there are good sales.  She will tell you shopping can be a bit frustrating, but I think she is in paradise.

 

If you are a manufacturer you want to be able to sell everything you make.  This means you need a good design - that is up to the designer, but you need to know the distribution of women's sizes.  You don't want to make as many size 0s as size 8s or 10s.  If 20% of your customers are size 8 you should make 20% of your line in size 8.  If 5% are size 4, you make 5% in size 4 and so on.   At some point it doesn't make sense even stocking sizes where there will be few customers  On the small side you rarely see many size 0s or 2s in stores.  It gets worse when you add tall sizes and that usually means something like 5'8 to many manufacturers.

 

You have probably seen the bell shaped curve in your math class.  These are often called gaussian distributions and many things in nature, including human height, come very close to following them.  I won't go into the math, but we are at the right end of the scale.  Depending on how you count, only about 1 in 20,000 women are my height or taller in the US. This sort of makes sense when I travel around.  I have two very tall friends.  One is 6'7 and the other 6'8 and at that height we are talking about one in more than a million.  It does not make financial sense making manufactured clothing even at my height. But you may be able to mix and match pieces that fit here and there.  My 6’7 friend can get by with short sleeved tshirts and jeans are ok as long as she wears them as cutoffs.  But dresses, nice slacks, and jeans that really fit simply don’t exist in stores.

 

But it gets worse.

 

Most women in America are a bit on the heavy side.  About two thirds are considered overweight and a third obese.  This means that plus sizes are the common size.  Why is it so many women who are size 14 and up can't find clothing that fits if the average woman requires these sizes?  A lot of women blame the manufacturers and models for an image that is super thin and unrealistic.  This isn't true.  There are marketing reasons why models are tall and thin, but not reason for a manufacturer to leave money on the table by not offering clothing to a large number of women who want to hand over cash for something pretty.

 

The problem goes back to how clothing is made.  I mentioned ready to wear.  That started to become popular in the early 20th century.  It became very cheap to mass produce large number of clothes in sizes that would sort of fit the majority of women.  Before then you had to sew or use the town dress maker and clothing, for most women, was expensive and lacked style.  Few dressmakers had the skill to make beautiful togs.  With ready to wear quality improved and the price dropped.  It caught on. 

 

Before mass produced and sized clothing caught on there were two basic ways to make it.  Bespoke and made to measure.  Bespoke is what it sounds like - you "speak" for a piece of fabric and, and in the hands of an expert,  a piece is made to fit perfectly.  There is no pattern and no concept of sizing.  It is still done today and in the hands of masters is the summit of clothing.  It is also mostly reserved for mens suits; suits that start around $5,000.  There are a few who will craft women’s clothing using this technique.

 

Made to measure is where the fabric and design is known but your measurements are taken.  The fit is much closer than ready to wear, but a pattern is involved.  If you are wealthy and go to a designer's Salon you can often have designs made to your measurements.  It usually takes a month or two of waiting along with a boatload of money.  Much more than I have.  

 

For ready to wear it was necessary to find a way to scale patterns.  Remember our size 8 fit model?  For hundreds of years - going back to the 16th century in Italy it had been known that women of average weight varied in a predictable way.  If a certain amount came off the bust, there was another amount that came off the hips and still another than came off the waist.   As long as these jumps were not huge you could make patterns, which can be very complex and hard to make, that would scale easily.  In made to measure adjustments could easily be made and you may have done this yourself if you have done dressmaking from patterns.  Additionally there are other parts of a design that can be altered, usually by a tailor, for the final fit.  But we are still waiting for something that fits heavier women, right?

 

The first real attempt for mass produced larger sized clothing was pioneered by Lenna Bryant in about 1910.  She had a dress shop and a client asked her for a maternity dress that could be worn on the street.  It was a big success, but it was considered unfashionable and no one would run ads.  Bryant and her husband decided this was a real business and started a mail order catalog.  Mail order was becoming popular sort of like the Internet of its day. It turned out many, if not most, of their customers were full-figured rather than pregnant.

 

Bryant's husband was an engineer who designed railroads.  He knew how to design curves in the tracks and used this knowledge with measurement statistics from thousands of life insurance records to define three or four basic full figured body types.  This made it easier to get a dress that mostly fit a woman of average stature and that was in a day when women could sew and alter or lived close to someone who could.  It was a pretty big advance. The Bryants refined their designs and became millionaires when a million was a huge amount of money.

 

But there is another problem.  Why aren't we just scaling from size 8?  It turns out the fuller figured women have very different curves and the range of those curves varies hugely.  There may be a size 16 fit model, but rather than fitting half of size 16s, she might only cover 10%.  The concept of size doesn't work anymore because the curves themselves are not being properly fitted. There is far too much variation.  Plus sized manufacturers try to do as best they can and try to find ranges of fit models that give them a better chance at making money, but for the majority of plus sized women the sad truth is they can't get the off the rack fit that their smaller sized sisters get.  The manufacturers would love to solve this as they could mint money.  There are even some good ways to do it, but that would be getting ahead of ourselves.

 

Of course none of us are of average height.  We have curves, some of us more than others.  But we also have legs, arms and torsos that tend to be longer than what "tall" sizes account for.  We have a few speciality manufacturers.  They are faced with the same problem a regular manufacturer has but it is worse. Not only do they have to guess the right size range if they want to sell enough to stay in business, but they have to know what percentage are.  5'10 to 6'0, 6'0-6'2 and so on...  You get a sheet of paper and draw a horizontal line with that bell shaped curve for size distribution. Depending on your line maybe most are size 6 through 12s.  Now you draw a vertical line and for each one of those sizes you try to figure out how many will be in each height range.  The space for 6'3 and size 0-2 has such a small number in it that you decide not to make anything specifically for that woman.  At 5'10 and size 8 or 10 there may be a large enough number that you want to have several designs.  For the fuller figured women it is very tricky as now as the type of curve becomes a more important variable.  And there is long and short waisted, etc. This is really really difficult and risky business.  You will please a few customers, but many won't have great fits and there can't be a big selection.

 

Ok, so far I've mostly given problems and things may sound hopeless. But they aren't.  Most of us manage by putting together something even if it doesn't fit great or have the fabrics and designs we would love to have.  If one of the speciality companies has a line that fits, support them!  None of these places makes a lot of money as the costs are high for low volumes. We have to acknowledge that clothing is going to be more expensive, so buy it and take good care of it.  If the fit isn't fabulous get to know a good tailor.  I have a great one.  She is about 70 and I bribe her with cake and chocolate even if I don't have something for her to work on.  Be creative and look at vintage and used clothing and work with your tailor.  Sometimes you can put together very interesting outfits for not a lot of money and it is much more your style.  Perhaps you can find a dressmaker or even learn yourself. One of my extra tall friends was complementing her neighbor on a beautiful dress and learned it was homemade.  Now that neighbor is making a made to measure dress for her and is making a little money on the side too.

 

Made to measure is the holy grail assuming the patterns can be matched well enough.  It is beginning to happen.  You may have seen shops that take a lot of measurements and turn them into clothing.  Indi is one that does semi-custom jeans.  What they do is create a pattern in the computer that is unique to you and then that information is used to run a machine that cuts the fabric.  People sew it together and if that is done right and the measurements are good, it should fit well.  These places offer a bit of customization.  Now your height and shape are much less important.  It is expensive now, after all it is competing against designs made in the third world by women who only made a few dollars per day at most.  

 

This is a developing area and there are problems, but it will probably get much better.  In the mean time develop an eye for style, find a good tailor or dressmaker and learn a bit of sewing.  

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* 5.6 sd is very rare and a good illustration that the distribution of human height is only approximated by a gaussian.  Specifically it implies that she is taller than all by one in about ninety three million women in this age range.  Looking at women's basketball teams this clearly isn't the case and a more realistic number based on other work is probably between three and ten million women with six million being a good guess.

A male her height is much more common at 3.6 standard deviations from the mean - about one in sixty three hundred men in this age range.  The male curve is only slightly non-gasssian that far out if you use the largest data sets.  

It turns out most of the error in the tails in induced by sampling.  The study of rare events demands extra care with normal techniques and tools often breaking down unless unless you have a good fundamental understanding of what is going on under the hood.

If you want to probe human height more deeply an excellent non-technical article appeared in The New Yorker in 2004 - The Height Gap by Burkhard Bilger (fortunately not behind their paywall).  Having a tall friend opened my curiosity on the subject and I have spoken with some of the researchers mentioned and then branched out a bit.  It turns out the height of a population (not individual height!) is a good proxy for health.  In the US female height has been falling in the past few decades and male height is relatively stagnant.  

 

 

some daydreaming for a hot summer day

It is approximately hot in New Jersey today.  A few years ago I wrote about trying the trick of starting a fire in the Winter with ice.

____________

Years ago I was snowed in on a beautiful sunny day and it struck me that this might be possible.

You need very clear ice.  I had a bucket that had been collecting snow melt the day before and the night was cold enough to freeze it nicely and clearly. About half the ice was very clear and the rest cloudy.  I had a piece of metal to use as a chisel and a little hand saw.  The hand saw was the most effective -  I carved a small cylinder and then worked on making it into a rough sphere.  Then polish it like you were making a snowball.  My gloves were just abrasive enough to do a really nice job on this.  

My aim was a snowball size as that would be easy to polish -- it came out a little small, but it worked well.  There are probably better techniques than mine, but I think a spherical lens is going to be the easiest to fabricate

The focal length for a spherical lens is short, which makes aiming it very easy.

I had tried a few designs that looked more like conventional one sided convex lenses, but they were too difficult for me to make.  The total trial and error phase took several hours and well over a quart of hot chocolate and a steaming bowl of chili.  Once the aha moment hit and I settled on the spherical design, it  only took 10 minutes - but my ice carving skills were pretty good by then.

 

the omenti blog

It's about time.

By way of introduction I'm Steve Crandall.  My Ph.D. is in experimental particle physics, but after scattering quarks for a few years I went to Bell Labs and started to branch out and acquire a broader set of interests.  I tend to combine fields without much regard to label and for the past fifteen years have been most active in the boundary regions between technology and people.  

There are a few approaches used by people who are generally labeled technologists.  Mine isn't better or worse, but combines my background in pure and applied physics with a strong amateur interest in the social sciences and the arts.  It tends to be different from the traditional engineering technologist's approach and you may find it interesting.

In the blog I'll mostly post little threads that may be of general interest so it may bounce around a bit.  Also I'm setting an upper limit of an hour's worth of work per post and many of the posts will not be carefully proofed.  Expect some typos and outright misspellings and grammatical errors. I want to keep it similar in tone to just chatting with someone.

For a deeper introduction here is a TED^x talk I gave last October in Manhattan.  I was told the audience would have a lot of artistic types - artists, fashion designers and architects.  The theme was collaboration and serendipity so I tried to weave some threads that might amuse people even though it is somewhat different from my normal work.  I'm not a great speaker, so please bear with me