The Sorry State of Healthcare in America- How Can We Fix This?

Ryoan-ji Temple

The Rock Garden of Ryoan-ji, Kyoto (Photo (c) by Frantisek Staud)

Are we presently at the dawn of a new “golden age” of medicine? There are some amazing things happening today regarding cancer treatments. But is further progress being hampered by a moribund medical establishment? 50 years ago health insurance was known as “hospitalization”, because that’s about all an insurance policy covered. When one went to the doctor back then you got treated and paid your $20 or whatever on the way out and that was it. No co-pays, no paperwork hassle, just a simple business transaction. Same thing when you went to the drugstore.  And nobody seemed to complain about the cost of health care. But there were still people who couldn’t afford to pay even the modest amounts doctors charged then, but somehow the medical profession by and large was able to absorb these “charity” cases and still make a decent living for doctors. Doctors themselves were mostly independent practitioners, running their own businesses. As an economic model, that seemed to work pretty well for them. But somewhere along the way doctors lost control of their pricing and their independence.

Over time companies began to offer increased benefits for health care, offering to pay for routine doctor visits, even some prescription medications, and lowering the deductibles for hospital care. More and more people came to view health care as a right, and as benefits increased many began to abuse the system, treating health care as if it was free since the benefits and insurance systems hid the true cost of providing health care. It should not have been surprising then that the demand for something perceived as free would force annual increases in health care spending running several times the rate of inflation. Being a limited resource, this also caused prices for services to rise accordingly. The one positive outcome of all this was research into new and better therapies was well funded, the financial incentive being there to find a cure no matter what the cost since patients were insulated from the consequences of expensive treatments.

As therapies improved and positive outcomes became the norm rather than the exception another problem soon arose. Medicine came to be viewed more as a science instead of the combination of science and art that it truly is. If doctors and other medical professionals really knew what they were doing they’d be referred to as medical engineers rather than ‘practitioners’. People’s expectations of uniformly positive results began to result in lawsuits for medical malpractice at an increasing rate due to the occasional negative outcome. In the past, malpractice suits were not all that common and were typically brought about by genuine mistakes or poor doctor performance. As a result most of the time these suits were quietly settled. But as the number of suits increased and settlements continued, patients found that even frivolous lawsuits wouldn’t be contested and so an explosion of so-called malpractice lawsuits ensued, further driving up doctors’ overhead. As a result, 25 cents of every medical dollar today is siphoned off by an insurance company, doing nothing to improve health care. Doctors’ private practices, squeezed on the one hand by sky rocketing malpractice insurance premiums and on the other by insurance companies that told doctors what they were going to pay for patient care, not what the actual cost really was, began to abandon private practice and join up with hospitals and other types of providers in a bid for survival. In doing so they gave up the last vestiges of control over what they could charge for their services. The cost of a medical education in America now typically exceeds $400,000. Having lost control over their pricing, a doctor graduating today may have such a poor return on that investment once all the student loan interest piles up that they’ll never be able to repay the cost of their education. This will result in two things: 1. a doctor shortage, and 2. a rising tide of mediocre care.

In the second decade of the 21st century we’ve arrived at the point where we have the world’s most advanced medicine but few can afford it. Friends of ours recently visited a prestigious hospital in a major city and were told that the minor cancer surgery he needed would cost them $150,000 and they had to pay up front. Needless to say they walked away from that. Another friend, treated at the same facility, was billed $90,000 for a one night stay and surgery to remove kidney stones. He had “insurance” so he didn’t have to pay this, but what did the hospital really get for this? Surely not $90,000. But without pricing transparency who knows? Poor people are getting health care for the most part however. Just go visit any big city hospital emergency room, particularly on the weekends. There will be many poor people waiting for treatment since by law hospitals can’t turn them away. But this is a very inefficient way to serve them, and the hospitals recoup their costs by overcharging other patients and insurance providers. The few doctors who remain in independent practice are still getting squeezed. One obstetrician whom I know has an annual malpractice insurance bill of over $250,000, and he’s never been sued. Others refuse to participate in the government sponsored programs for the poor and elderly, Medicaid and Medicare, because the government takes over 9 months to pay off on claims. Anywhere else in business when receivables go over 120 days they get sent to a collection agency. The government’s solution to the problem, the “Affordable Care Act”, only made things worse. So now, because of ObamaCare, people lucky enough to be able to afford health insurance policies now find that their deductibles start at over $6,000 and go up from there, so what’s the point in having insurance in the first place?

So where do we go from here? How can we make health care in America truly affordable again? As a first step, all health care providers, from independent practitioners to the biggest hospital complexes, would be required to publish prices charged for their services. All patients and prospective patients would be required to be presented with a cost estimate of their proposed treatment plan and possible options for payment. Costs for routine office visits and common lab procedures would be prominently displayed in doctors’ offices. Doctors would even be allowed to include pricing in advertisements.  Insurance companies would be prohibited from dealing with hospitals directly. Patients would be required to submit bills and treatment proposals to their private insurance companies. Hospitals could offer their own plans, so-called concierge plans where for a fixed sum they could offer ala-carte medical services. But patients or their guardians would be required to review all expenses related to their own treatment. Patients could also shop around for more cost effective treatments if they desired, bringing market transparency to bear. The second thing sorely needing addressed is tort reform to reduce the incidence of frivolous lawsuits. The threat of a malpractice lawsuit should still be available in order to keep hospitals in particular accountable, but it should be harder to bring such a suit and suits that are deemed frivolous and are thrown out by the court should result in the plaintiffs paying the court costs.

In the end, it may be that old fashioned competition could ultimately bring about reform. It’s now possible to fly to Malaysia, the world’s top medical tourism destination in 2016, for example, undergo knee replacement surgery, recover in a 5 star hotel for some time after leaving the hospital, then fly home all for about one half to one third the cost of a typical knee replacement surgery in America, including the hotel stay and air fare. So called medical tourism is the fastest growing industry in Malaysia. Other countries such as India, Thailand and Brazil have also discovered the wonders of fixed-price procedures and pricing transparency. A few enlightened insurance plans are beginning to recognize this as well. Even something as simple as Laser eye surgery can be done in Turkey for $1100 for both eyes. So it might just be that old fashioned competition could be the answer to affordable health care in America. Mainstream insurance companies will probably be the last to embrace this, although there are a few private plans and at least one Christian health care sharing ministry that support overseas healthcare providers.  At least 16 hospitals in Malaysia have received the highest possible accreditation from the same organization that certifies hospitals in America.  We seem to import most everything these days, why not health care as well?

Simulating a Brushed DC Motor with LTSpice

Note: you will need Javascript enabled to properly view this page.  LTSpice files for this article can be found on Github here.

Recently we were asked to help troubleshoot a problem a customer was having driving a DC motor.  Needing more throughput, they changed to a more powerful motor but then began having problems with the controller board.  Since they were driving the motor with a PWM output to control the speed it seemed like the system would be amenable to simulation using LTSpice.  Brushed DC motors are rather simple beasts, they have a fairly linear transfer function (input current to output torque) over a moderate range of operation, and there aren’t too many nasty parasitics to deal with.  The file archive of the LTSpice mailing list has a model of a DC motor but it did not allow for applying arbitrary loads to the motor.  A model for LTSpice is described here at the University of Colorado which allows us to load the motor model with various amounts of torque to gauge the motor’s performance.  Spend some time looking over that presentation then come back here where I take a look at a real world example.

Deriving parameters of the motor needed for simulation can be a bit tricky.  We need to measure the winding resistance and inductance and the current through the motor at a couple different operating points.  Measuring the DC resistance accurately is probably the most critical of these.  Motor speed can be accurately measured with an oscilloscope.  Winding inductance can be measured with an LCR meter or a bridge or even an oscilloscope.  Taking a look in the junk box to see what we might be able to use for a victim we found an old window lift motor still in pretty good shape.  This type of motor is operated with a heavy overload and is designed for short intermittent operation so we have to be quick when making measurements, particularly at full speed.  It’s also likely to not be very efficient.  Prepare to make the measurements by putting a little power to the motor and let it spin up a bit to seat the brushes and clean off the commutator so we can make accurate measurements.

meter connection to motor setup

Meter connections for making motor measurements.

Step 1: Measure DC winding resistance.

The method I chose actually gets us two things we need to know, the winding resistance, and the ‘Tloss‘ parameter needed to model the motor’s mechanical side.  The process is simply to connect the power supply to the motor with an accurate current meter in line, and make Kelvin voltage connections to the motor leads with a voltmeter.  Start off with the power supply output at 0V and slowly increase the voltage until the motor starts to turn.  Adjust the voltage up and down to find the point at which the motor just stops turning, and a very slight increase in current will cause it to begin moving again.  Fine tune this as best you can, since the value of the current is critical for computing Tloss.  Take readings of the current and voltage at this point and simply apply Ohm’s law to compute the DC winding resistance:

`Rm = (Vm)/(Im)` or `Rm = 0.714/1.741`

which works out to about 0.410 ohms.

Step 2: Compute motor K constant.

The next parameter to measure is how effectively the motor converts current into useful work measured as output shaft speed and torque.  We applied 6V to the motor and measured the input current and shaft speed.  To measure the shaft speed we just took the scope probe and touched it to the worm gear.  Once every revolution the gear would bump the tip of the probe and allowed us to make an accurate measurement of the shaft’s speed.  The measured frequency of the pulses displayed was 44.25Hz.  Shaft speed `omega` is given in terms of radians per second so simply multiply 44.25 by 2`pi`.  A second set of measurements was made at full rated voltage of 13.8V.  So now we have:

At 6.0V: input current 2.318A, `omega` = 278
At 13.8V: input current 2.68A, `omega` = 690.5

"Ghetto" method of measuring shaft speed

“Ghetto” method of measuring shaft speed

dc_motor_scope_view

Shaft rotation rate is easily determined.

We also need to find the back EMF at each operating point in order to compute motor constant K. The general formula for current through the motor is given by

`Vapplied-Vemf = Lm*((d(I1))/dt)+Rm*I1`

In this case since we are measuring things at steady state the inductance term drops out and we are left with Ohm’s law to find our back EMF of 12.7V for the 13.8V operating point.  Since the motor constant K, back EMF and shaft rotational speed are related by

`Vemf = Komega`

we now can find our motor constant K to be approximately 0.0184.  For our other measuring point at 6.0V K works out to about 0.0182, noting that at lower input voltages fixed internal losses will have a greater effect (consume more of the useful work) so this seems to make sense.  Our internal torque loss Tloss can now be computed using the formula

`Tloss = K*I`

where I is the current we measured when finding the winding resistance with the motor shaft not turning.

Step 3: Measure winding inductance.

We’ll admit we punted here and simply used our trusty HP LCR meter to simply measure the winding inductance.  Note: it helps to jog the shaft slightly to ensure the motor brushes are only making contact with a single rotor winding circuit, as evidenced by the readings on the LCR meter.

Step 4: Load parameters and fiddle the model.

There are two parameters for the mechanical side of the model, the moment of inertia and coefficient of friction, that may need slight adjustments in order to achieve correlation with measured motor performance. The default output from the ENC pin on the model is the shaft speed in radians per second remember, so the first order is to see how the motor behaves on startup. The input current should exhibit a slightly over damped response.  Adjust the value of the J parameter until the input current and shaft speed curves exhibit reasonable behaviour.  Without an external load the motor should spin up pretty quickly.  Adjust the unloaded output shaft speed by making slight tweaks to the B parameter so the no load shaft speed matches the measurements on the bench.  And that’s it!  We can now apply varying loads (in Newton-meters) to the motor to see what happens to its shaft speed and input current.  The motor model can be used in a circuit with PWM drive but note that all inputs and outputs to the motor model will have to be referenced to its ground terminal for things to work properly.  There are some optional things in the motor model.  For example if you want to simulate the output of a shaft encoder you will need to tweak things to get the right number of pulses per second and plumb up the arbitrary voltage source B2 to get pulses out instead of the shaft speed in radians per second.  But once again LTSpice proves its great utility at doing simulations of all kinds, not just purely electrical circuit simulations.

Why Oboes Crack

The "White Heron" castle of Himeji

The “White Heron” castle of Himeji

Before we even begin discussing why instruments crack the number one question on your mind right now probably is “Can I absolutely prevent my instrument from cracking?” The answer unfortunately is ‘no’, BUT there are things that can be done which greatly reduce the likelihood that an instrument will crack. I will caution you right now that there are many opinions about how to prevent cracking and how to properly care for a wooden instrument, not all of which are grounded in an understanding of how wood works.

African Blackwood (grenadilla) tree trunk cross section

African Blackwood (grenadilla) tree trunk cross section

The wood which most oboes is made from comes from the African Blackwood tree. It’s also called grenadilla wood, and is similar to other deciduous hardwoods. The section of the tree used for instruments is the center of the trunk, the heartwood. The tree when lumbered is usually cut up into billets of various sizes, taken from the best of the heartwood. Since these trees don’t grow very straight the number of useable billets from each tree is fairly low, one of the reasons the wood is so expensive. It’s just like making reeds where 99% of the harvested cane is eventually thrown away in order to get to decent tubes.

Blackwood billets after lumbering

Blackwood billets after lumbering

To understand why instruments crack we need to first take a look at how wood behaves under different circumstances. Let’s look at a blackwood billet, see illustration below:

Wood5

Note that the grain direction always runs in the same direction as the tree trunk. This is also the major strength axis of the wood. For example, if you were to attempt to split the piece illustrated above in two by striking it with an axe on the end or on the side in the same direction as the grain it would split apart with little effort. But striking the wood across the grain on the side yields nothing but frustration as it will not yield in that direction. Wood is porous and will easily absorb moisture on the ends due to capillary action. It will also absorb moisture through the sides across the grain but not as readily. It’s critical to note here that wood is NOT dimensionally stable across its width, that is, across the grain. Very little expansion and contraction due to moisture occurs along the wood in the direction of the grain, but across the grain the movement is significant, driven primarily by the moisture content of the wood, and to a lesser degree by its temperature.

When a tree is harvested and lumbered, there is a significant amount of moisture in the wood, usually much higher than the surrounding ambient humidity. Before wood can be made into instruments, it must be properly “seasoned”, that is, allowed to reach a stable moisture content. For furniture making a moisture content by weight of around 7% is considered ideal, so to season wood properly it must be stored for several years in an atmosphere of around 35% to 40% relative humidity. Because of the density of African blackwood typical seasoning times are at least 5 years. Once an instrument is machined from billets of blackwood the machining process itself can relieve stresses built up in the wood created whilst the tree was growing. Sometimes these stresses take time to work themselves out after all the machine work is done, resulting in slight dimensional changes to the instrument. This is one reason why there are no two oboes which are exactly alike even though they were made at the same time from the same batch of wood, even from the same tree.

So back to your original question, how do we keep our oboes from cracking? We must do things that minimize wood movement. Since it’s impractical to prevent all wood movement we need to learn to deal with it so that it does not cause cracking. M. Alain de Gourdon of F. Lorée says that cracking typically occurs in cold and dry places around the world. In North America, instruments are particularly at risk because we tend to overdo forced air heating and air conditioning, both of which greatly reduce humidity and can create dangerous extremes of humidity and temperature from one location to the next.

F. Lorée ships a set of instructions with every new instrument on how to properly “break it in”. Following those instructions carefully will greatly reduce the likelihood of cracking:

The following will help you to get the most enjoyment from your new instrument and reduce the possibility of cracking. The risk can be minimized by playing the new instrument gently during the first few months, and by taking precautions during periods of low humidity.

In the beginning, play the instrument for no more than 10-15 minutes at a time. Swab it, return it to its case and keep the lid closed. A few hours later or the next day, you may repeat this procedure. Each week you may add five to ten minutes playing time. After about three months, you should be able to play it as you wish.

On chilly days (or in cold rooms) always warm the instrument before beginning to play on it. This may be done by holding it against your body for a few minutes, or cradling at least the top joint in your hands. If the oboe was left in an unheated area on a cold day, you must not play it until it has had a chance to warm gradually. [emphasis mine]

Avoid laying down the instrument on a cold or very warm surface or next to a heat source so that it is not exposed to rough variation of temperature. If your instrument is kept in a dry climate, or even during prolonged periods of dry weather, the best is to put a humidifier in the case to maintain higher moisture.

During the break in period, we recommend you to oil regularly the bore of your new instrument (about once a week). Be sure first, that the bore is well dried and cleared of moisture. Then put some drops of “F. Lorée” natural bore oil preferably on a feather and apply a light coat of oil gently inside the instrument. After a few months, you can progressively reduce to oil your instrument.”*

* From instruction sheet shipped with every new Lorée instrument, courtesy of Alain de Gourdon, F. Lorée

M. Alain de Gourdon recommends the use of their natural bore oil or natural almond oil. The idea behind oiling the bore is to reduce the wood’s ability to absorb moisture from your breath that condenses in the bore. Repeated oiling gradually infuses oil into the wood, displacing some of moisture that is there and preventing it from picking up additional moisture from your breath. Ideally at some point the oil will have displaced most of the moisture in the wood such that changes in ambient humidity and temperature will have a significantly less effect on wood movement, greatly lowering the risk of cracking. Also, don’t do dumb things like leaving an instrument in the car where it can overheat and crack in the summer or get chilled in winter. Outside in the winter keep your instrument under your coat. Always use an insulated case.

Oiling an oboe:

Refer to the instructions provided by F. Lorée listed above. Be sure the oboe is dry on the inside before oiling. Do not try to oil right after playing. Use a feather long enough to go through the top joint and stick out of the reed well when you feed it base first from the bottom. This might seem rather cumbersome BUT it keeps the feather from poking into the tone holes and leaving excess oil there which it surely would if you pushed it through from the joint. Put just 2 or 3 drops of oil on the end of the feather, then slowly pull it through while twisting it. Repeat this several times to spread the oil around but don’t add any more oil after the first pass. Feathers work best at spreading the oil around as they won’t absorb the oil. Viewing the bore against a light from the top the inside should be slightly shiny from the oil, but not soaking wet. Note that the first time you oil a new oboe the oil will soak in almost immediately. Keep tone holes pointed up throughout this process to keep oil from pooling in them. Oil can make pads stick so keep it out of the tone holes. After oiling, put the oboe away and let it rest for at least 24 hours to allow time for the oil to diffuse. Oil the bottom joint in the same manner. The end of the bell with all of its exposed end grain will absorb a lot of oil so the best way to oil the end of the bell is to put a drop or two of oil on your finger and rub it in, much like finishing fine furniture. A little bit of oil goes a long way. Too little is better than too much, especially after the first time. I also apply a small amount of oil to the wood under the thumb rest and the first octave key since these areas can absorb a significant amount of moisture from your thumbs.

The use of natural almond oil was mentioned. This is also known as sweet almond oil and is usually available at any health food store or natural market. This is a cosmetic grade (as opposed to food grade) oil. Cosmetic grade oil has stabilizers in it which keep it from getting rancid or gummy. Petroleum based oils should be avoided, these can cause the wood to deteriorate. Vegetable oils should be avoided as well as these will eventually get rancid and gummy. When in doubt use F. Lorée natural bore oil. You should continue to use only the kind of oil that was first applied to the instrument for all future oilings.

Years ago oboe players tended to keep their instruments for much longer periods than professional players do now. The legendary English oboist Leon Goosens played on the same USED Lorée oboe for 40 years and it never cracked. But he was a little extreme in the care of his instrument. Once a year he would remove all of the key work and thoroughly oil it inside and out. He would then allow it to rest to let the oil soak in before reassembling and adjusting it. That’s definitely over the top for most of us. Over oiling an instrument is not a good thing. If there’s too much oil in the wood it will tend to ooze out and cause pads to stick. There is no way to remove excess oil from the wood, so don’t overdo it.

If left to acclimate properly an oboe will be perfectly happy in a tropical country, but in colder climates some effort may be needed to maintain a minimum level of moisture content in the wood. There is a lot of FUD surrounding the use of humidifiers in one’s instrument case. Some people even put orange peels and other silly things in their cases in order to raise the humidity inside. Don’t do that. Only use a device specifically designed to perform this task. Remember that humidification is called for only if the instrument will be kept for long periods of time (more than a day or two) in an environment where the relative humidity is low. In North America relative humidity indoors in the winter can drop to 20% or below due to excessive heating. A humidifier is called for if the humidity in the environment where the instrument is stored is below 40%. As with oiling, humidification can be over done. Excessive moisture will cause the wood to swell, leading to all kinds of unwanted movements, possibly even cracking. The sound will be affected as well.

Why oboes crack:

Note that an instrument will take up moisture somewhat more quickly than it will release it, which is why it’s so important to oil it and to control extremes of temperature and humidity that an oboe is exposed to. Cracks occur due to a buildup of stress in the wood because of differences in moisture content and temperature between the bore and the outside surface of the oboe, almost always in the top joint. The top joint is particularly vulnerable to cracking due to its smaller overall diameter than the bottom joint, the greater difference between the inside (bore) diameter and the outside diameter, and higher temperature saturated air from the player’s breath, which is much cooler by the time it reaches the bottom joint.

Relative cross sections of the top joint (left) and lower joint.

Relative cross sections of the top joint (left) and lower joint.

Warm moist air passing through the top joint diffuses moisture into the sides of the bore, and along with the warmth causes the wood to swell. Compression stresses build up in the center and work their way outward against tension forces from the outside in until something gives and a crack opens up.

Crack formation in the top joint

Crack formation in the top joint

This is why cracks usually appear on the outside surface and may not work their way through to the bore. Remember that across the grain of the wood is the weakest strength axis, which is why cracks typically form along the length of the top joint or between the tone holes. Reducing moisture absorption in the bore goes a long way to help prevent cracks, hence the need to oil early and often in the life of a new instrument, and to carefully maintain its environment.

Post copyright (c) 2016 Jeffrey W. Sutherland.  All rights reserved.