February 27, 2016

Aerospace Defense and Technology, February 2016 publication, presented a fascinating article on joint engineering efforts provided by Aerion and the Airbus Group relative to a new supersonic business jet. This team has dedicated design and production planning since 2014, which has definitely been productive with a mid-November announcement from Flexjet ordering twenty (20) aircraft.  Aviation Week made the announcement as follows:

“Flexjet has placed a firm order valued at $2.4 billion for 20 Aerion AS2 supersonic jets, with delivery to begin in 2023. First flight is expected in 2021.

Flexjet CEO Kenn Ricci said the company will use the supersonic jet for overseas flights and also in China, which does not have restrictions on sonic booms.

Customers are already excited about the jet, he said. They immediately began citing city pairs where they would like to fly. But no one wants to fly it sub-sonically, Ricci said. The AS2 can fly sub-sonically over land in the U.S., Europe and areas where the boom is restricted. But it won’t be cost-effective to do so.

The three-engine jet will burn a high amount of fuel, roughly 1,000 gal. Per hr., and its long length will restrict its use at some airports, Ricci said. “It’s still going to be an expensive plane to operate,” he said. Still, with the aircraft traveling at Mach 1.2, its boom will not touch the ground, Ricci said. Because of that, regulators may be able to be convinced to allow the jet to fly supersonically across the country, he said. Even so, the aircraft can be placed at points on the Atlantic and Pacific for international travel.”

The digital photograph below indicates the basic airframe and shows the three engines designed into the fuselage.

Aeron AS2

Kelly Johnson, leader of the famous Lockheed “Skunk Works” stated years ago; “If it looks like it will fly, it will fly.  Well, this one looks like it will fly.

This biz jet will hold eight to twelve passengers and will have an intercontinental-capable range of 4,750 nautical miles at supersonic speeds.  At these speeds, three hours will be cut from traveling across the Atlantic and more than six hours on longer trans-Pacific routes.  It could get you from London to New York in 4 hours and 24 minutes. It takes a normal jet about seven hours to make that trip. The typical flight time from Los Angeles to Sydney, Australia is about 15 hours and 30 minutes. On the Aerion AS2, the flight time would be just ten hours.

The AS2 will fly at a speed of Mach 1.5, using supersonic laminar flow technology.  The wing design will allow for lighter fuel consumption and increased travel ranges by reducing aerodynamic drag by twenty percent (20%).  NASA has issued a contract to model supersonic boom at ground level to ensure no issues result from supersonic flight.   New noise regulations coming in 2020 caused Aerion to change design from two to three engines to meet upcoming noise specifications.

The three-engine jet will make its first flight in 2021 and enter service in 2023.

As you can see from the digital below, the design is definitely cutting edge.  Other specifics are as follows:

 General characteristics

  • Crew: 2
  • Capacity: 8–12 passengers
  • Length: 170 feet (51.8 m)
  • Wingspan: 61 feet (18.6 m)
  • Height: 22 feet (6.7 m)
  • Wing area: 1,350 ft² (125 m²)
  • Empty weight: 49,800 lb (22,588 kg)
  • Max. takeoff weight: 121,000 lb (54,884 kg)
  • Powerplant: 3 × turbofans (low bypass ratio), 16,000 lb s.t.
  • Cabin size: 30 feet long, 6’2″ high, 7’3″ wide (9.1 * 1.9 * 2.2 m)


  • Maximum speed: Mach 1.5 (1140 mph) 1837 km/h
  • Cruise speed: Mach 1.4
    • Mach 0.95 at lower altitudes to minimize noise
    • Mach 1.1–1.2
  • Range: 4750 nautical miles  to 5300 nautical miles (8797 km to 9816 km)
  • Controls: Fly-by-wire flight controls
  • Structure: Ten (10) spar carbon fiber wing structure, fuselage and empennage structures.
  • Landing Gear: Articulating main landing gear system that minimizes space requirements when stowed.
  • Fuel System: A fuel system that is integrated with the digital fly-by-wire control system for control of center of gravity

Aerion and Airbus are presently working to specify the engines for the AS2 while keeping in mind the upcoming noise requirements.  Their goal is to provide acceptable fuel usage just below MACH 1.


The interior is an absolute dream, as you can see from the next two JPEGs.  Talk about first class.


Interior (2)

This aircraft “ain’t “cheap but will serve a very specific function and is targeting a very small clientele.  Of course, there are no figures on how much this mean ride will cost relative to operating expense or maintenance but payback will have to result or there will be issues with cash flow and continued operation.  This one will be fun to watch.


February 22, 2016

We live in fascinating times!  Long gone are the days when individuals have only one employer.  The median number of years wage and salary workers had been with their current employer was 4.6 years in January 2014, unchanged from January 2012.  This is according to the U.S. Bureau of Labor Statistics. For women, the median tenure in January 2014 was 4.5 years, unchanged from January 2012. Among men, thirty percent (30%) of wage and salary workers had ten (10) years or more tenure with their current employer, compared with twenty-eight (28%) percent for women.  Median employee tenure was generally higher among older workers than younger ones. For example, the median tenure of workers ages fifty-five (55) to sixty-four (64), (10.4 years) was more than three times that of workers ages twenty-five (25) to thirty-four (34) years (3.0 years).  A larger proportion of older workers than younger workers had ten (10) years or more tenure.  Among workers ages sixty (60) to sixty-four (64), fifty-eight (58%) percent were employed for at least ten (10) years with their current employer in January 2014, compared with only twelve (12%) percent of those ages thirty (30) to thirty-four (34).

We are getting older and as aging employees retire, CEOs, presidents and human resource managers must look to younger individuals to fill the vacant positions.  This brings on fascinating challenges that certainly must be met.  Just what are the TOP TALENT TRENDS?  Let’s take a look.

  • INTERNET OF THINGS (IOT)— There is absolutely no doubt about it, IoT is the next technology mega-trend affecting the entire business spectrum. IoT is a network of physical objects or “things” embedded with electronics to collect and exchange data.  All sorts of data.  We see more and more “things” being connected to the internet each day. Every design manager recognizes this fact.  Companies are racing to make this happen.   Workers will have to develop new skills to meet the challenges of this environment.  People who know how to write code as well as hardware specialists will have to get on board for this revolution in products. Its coming and in many cases, already here.
  • THE BOOMERANG EMPLOYEE—An employee who leaves your company and then returns at a later time is called a boomerang employee. There, of course, reasons why an employee leaves; i.e. additional education, bad chemistry between manager and employee, great opportunities elsewhere, etc.  Seventy-six percent (76%) of employers say they are more accepting to rehire an employee is that employee did not create real issues during his original time with the company.   Rehiring a former employee can make sense.  They are familiar with company culture, may not require much training, and bring with them new perspectives.
  • GENERATION “Z” ENTERING THE WORKFORCE—Generation “Z” is the generation born between 1994 and 2004. According to Forbes, in 2015 Generation Z made up twenty-five percent (25%) of the U.S. population, making them a larger cohort than the baby boomersor millennials.  Frank N. Magid Associates estimates that in the United States, fifty-five percent (55%) of Generation Z are Caucasian, twenty-four percent (24%) are Hispanic, fourteen percent (14%) are African-American, four percent (4%) are Asian, and four percent (4%) are multiracial or other.

Non-traditional households are one of the most prominent features associated with Generation Z’s familial culture. In the 2010s, fewer women are having children (around 80 percent of those of childbearing age, against 90 percent in the 1970s), and those who do have fewer children at a later age.   Marriage rates have fallen as well as divorce rates, which are still relatively high. According to the U.S. census of 2010, both women and men get married at a later age– women’s first marriage averaging to the age of twenty-six (26) and men’s to the age of twenty-nine (29). This is due to the popular idea of becoming financially and emotionally independent before beginning a life with a significant other or children. Multiracial families have also become very prevalent.  In the U.S. census of 2001, 6.8% of people under the age of eighteen (18) claimed to be more than one race.  In addition to an increase in multiracial families, there are more same-sex marriages and families in communities across the country.  This is GEN “Z” and they are looking for employment.

  • HYBRID TALENT DEMAND—I think this is a big one. Hybrid jobs are the future of jobs.  Andy Holt, the past president of the University of Tennessee told the graduating class: “Know something about everything and everything about something”.  This in a nutshell is hybrid knowledge.  A hybrid employee is considered both a generalist and a specialist.  With a hybrid employee, employers are basically getting two people for the price of one.
  • INDUSTRY GROWTH CREATING NEED FOR FLEXIBLE SKILLS DEVELOPMENT—Accelerated growth produces the great need for an employee to be flexible relative to needed training and on-the-floor-experience. If an employee is not willing to learn, thus retrain—don’t hire him or her.
  • LONGER HIRING PROCESS CONTINUES—The time to fill a given job is lengthening. In April of 2015, the average job was vacant for 27.3 days before being filled.  This nearly doubles the 15.3 days it took prior to 2009. Better hires come out of the process but it does take time—much more time.
  • OFFICE DESIGN IS BEING USED TO ATTRACT TALENT—I find this one to be fascinating. Studies have shown that by transforming the look of the workplace, companies can create a more effective and productive space for their workers. For that reason, many companies are focusing on redesigning their office environment as a key aspect of attracting and retaining the best talent.  Health and safety are no longer considered adequate to attract employees.  They go for ambience also.
  • MORE WORKFORCE FLEXIBILITY—With the great rise of telecommuting, globalization and new technology, workers are demanding more flexibility. It definitely has not yet been determined as to where employers draw the line and I am positive this varies from company to company. With GEN Z, companies will have to bend with the winds of change and those changes are coming.


February 21, 2016

From McKinsey Global Institute and International Data Corporation, the following e-mail usage may be seen:

  • 28% of our workweek is spent reading and answering e-mail.
  • 650 hours per year is involved with reading and writing e-mail.
  • 13 hours per week, on average, is spent with e-mail

There is absolutely no doubt that e-mail communication has changed the manner in which business and personal correspondence is conducted.  In preparation for this post, I counted the e-mail sent and read over a two day period of time.  The results were mind-boggling– two hundred and four (204). I was, and remain, blown away.  I actually had no idea as to the number.  Now, I run an engineering consulting business and write posts such as this in my “spare time” but still, give me a break, two hundred and four.

One of my favorite web sites is  That media outlet provides a great service with several articles or “news you can use” each week.  One that really attracted me was the improper use of e-mail.  Those errors frequently made that produce problems for the reader and the sender.  Let’s take a look at the most egregious, at least in their opinion.

  • Using Improper Tone— Although these are not in order of severity, this one must be one of the most damaging. Who is your audience?  Who are you directing your e-mail to?  I would suspect the tone of your e-mail would be considerably different if it’s your boss as opposed to a peer or friend in the “cube farm”.  Senior management may not have time for the trivia you would use in communicating with a family member or a friend and you certainly would not use inflammatory rhetoric when addressing and informing someone up the line.
  • Hitting the “Reply All” Button—Consider the relevance of the e-mail. Generally, it is necessary to respond to the sender and not everyone on the senders list.  In doing so, you can drastically reduce the number of e-mail received each day.  You really do NOT have to tell the entire world. Now, if you are on a broadcast group and everyone needs to be included, you are perfectly correct in replying to all.
  • Writing Too Much—I plead guilty to this one and really have to watch myself. How much detail do you really need to impart?  Will a few words suffice?  Can a simple one-liner get the communication process taken care of?  Be concise but not wordy.
  • Forgetting Something so Resending Becomes Necessary—We have all done this; forgotten to attach an important document only to have the recipient of the e-mail indicate, with another e-mail, that you forgot to include the attachment. Been there, done that, got the “T” shirt.  I have also been guilty of sending an incorrect document. One I did not mean to send.  This makes it necessary to properly apply a file name that perfectly identifies the document.
  • Providing a Link That Does NOT Work—This is really frustrating if you are the recipient. You try, and try and try but nothing happens. You e-mail the sender back asking for help or another way to access the material.  Very time-consuming and counterproductive.  By the time you get the proper link, you just might be to put-out to give it a try.
  • E-Mailing the Wrong PersonThis one could be a career-ending event. BE CAREFUL.  Make absolutely sure the intended person gets his or her name in the correct block.  This also includes the copy block and the silent copy block.  This is BIG.
  • Too Emotional—When sending e-mail, do NOT wear your emotions on your sleeve—NEVER do this. A phone call or a visit is the way to go here.  Remember, e-mail is ever-lasting.  Long after the “rapture” your e-mail will exist.  Again, be careful.
  • Not Using “Delay Send” – I do not use delay send very much but scheduling the timing for an e-mail sent can be a very good practice when you are faced with a very hectic day. I definitely need, on a personal basis, to consider this one more often.
  • Using Vague Subject Lines—This can also be very frustrating if you are the reader. Be concise. Be distinct. Be exact. Do NOT make the recipient read the entire e-mail before he or she knows, or is required to guess,the subject.  This, in my opinion is certainly rude and time-consuming.
  • Not Reviewing Prior to Sending
    • Spell Check
    • Critique Your Grammar
    • Critique Your Punctuation
    • Do NOT Use Slang
    • Do NOT Use Abbreviations
    • No Bad Language
    • It’s an E-Mail NOT a Tweet
  • Sending Unnecessary E-Mails—If a visit or a phone call will do use them. An e-mail is NEVER a substitute for face-to-face communication. People like that.  It’s much friendlier and allows for questions to be asked and answered.
  • Avoid Sending When You Are Angered, Stressed or Too Tired—Just don’t do this. The importance of the communication will be lost if the message is send during periods of personal difficulty. (NOTE: Of course, this is baring medical or family issues.)  Never send an e-mail at night if it can wait until the next day.  No one likes to hear the “bing—bing” of an e-mail received at two in the morning.  Just don’t do this.
  • Many Companies Have an E-Mail Template—Use it.


I think these are excellent recommendations and ones I personally have violated over the past few years.  I will try harder and certainly hope you will do likewise if necessary.


February 20, 2016

The latest issue of Material Handling and Logistics has a fascinating article written by Adrienne Selko.  Ms. Selko is a senior editor for that very fine publication.  In her comment: “ I’m very concerned that the number of young me seeking higher education is dropping”.  She is correct.  The unemployment rate for Americans with bachelor’s degrees or higher is 3.2 percent, compared to a national average of 6.1 percent. So why, then, did college enrollment last year fall by nearly half a million?

Between 2012 and 2013, the Census Bureau reported 463,000 fewer people were enrolled in college. In fact, this is the second year enrollment has fallen by that much, bringing the two-year total to 930,000 fewer college students, bigger than any drop before the recession. The Census Bureau has been collecting this data through the Current Population Survey since 1966.  The facts are plain, if not very puzzling: Not only do women enter college at higher rates than men, but they’re less likely to drop out once they get there. Female grads now account for about 60% of U.S. bachelor’s degree holders. This is an absolute disgrace with significant consequences. The ratio should be at least 50/50.  We are doing something wrong with public education.

According to the White House Council of Economic Advisors, if males graduated college in the same proportions as women, there would be about fourteen percent (14%) more college graduates each year.  As it stands now, though, we could be facing a shortfall of two million workers over the next decade.  This is a very significant shortfall and one that will weigh heavily on commerce and the ability to hire qualified workers.

One probable cause—schools are NOT teaching the way boys like to learn.   Michael Gurian and Kathy Stevens of the Gurian Institute and piloting a two-year program in the Missouri School System aimed at greater retention of high school students and a great number going to and remaining in college.  Their program will include the follow:

  • Project-based education in which the teacher facilitates hands-on kinesthetic learning.  Learning will be project-driven as opposed to strict memory.  This type of learning seemingly has a focus and a desired goal in mind.  Successfully complete the project.
  • Teachers move around their classrooms as they teach.  The idea being, physical movement increases engagement from the boys. Years ago, and I do mean years ago, I had a typing teacher, Mrs. Spitzer.  She moved around constantly.  She was quite as a mouse and would  hang over our shoulders watching every key stroke we made.  It was really annoying but she found and corrected issues and problems that made the outcome very productive.
  • Students are allowed to move around as needed in the classrooms.  They are taught how to practice self-discipline in their movement.   If what you need is over there, why  not go over there?  Students should be allowed to move.
  • Teachers provide competitive learning opportunities, even while holding to cooperative learning frame-works.  Competitive learning includes classroom debates, content-related games and goal-oriented activities.  Students, particularly boys, are competitors.  They like challenges.

I have one thought not considered by Ms. Selko.  Ever watch television?  Ever notice how the “guy” is ALWAYS portrayed as the “dummy”.  The loser.  The fall guy. Ever notice?  If you tell a youngster he is stupid and repeat that pronouncement day after day, he will consider himself stupid and stop trying to excel.  It’s merely human nature.  Even worse, he will do stupid things.  “Dumb and Dumber”, “Caddyshack”, “The Jerk”, “Stepbrothers”, “Anchorman series”, ”Zoolander”, “Jackass”.  Notice a trend?  All guys.  OK, these are funny movies but we seem now to worship “dumbness” and forget that sometime the laughs translate to activities in real life—including dropping out of school.    We have to get over this.

One HUGE and disturbing static is the suicide rate for this country.

  • Suicide is the SECOND leading cause of death for ages 10-24. (2013 CDC WISQARS)
  • Suicide is the SECOND leading cause of death for college-age youth and ages 12-18. (2013 CDC WISQARS)
  • More teenagers and young adults die from suicide than from cancer, heart disease, AIDS, birth defects, stroke, pneumonia, influenza, and chronic lung disease, COMBINED.
  • Each day in our nation there is an average of over 5,400 attempts by young people grades 7-12.
  • Four out of Five teens who attempt suicide have given clear warning signs.

Kids who drop out of high school are more prone to try suicide.  That IS A FACT. Look it up.

I certainly hope Michael Gurian and Kathy Stevens are on to something and their program in Missouri is a tremendous success.  Our public school system is desperately in need of changes.  The challenges that will present themselves over the next twenty years are huge.  We need the brightest adults to meet those challenges.


February 12, 2016

Just when you thought it was safe to go back into the water, another all-electric automobile emerges from “drawing board” to concept car with hopes of becoming reality.  Faraday Future–which suggests you call it FF for short–says it will launch its battery-electric vehicle sometime during 2017, model FFZERO1. This is a very aggressive timetable and one which draws considerable skepticism from informed individuals in the automotive industry.

Future was established in 2014 and is currently based in Gardena, California. Since its inception in 2014, the company has grown to 750 employees globally.  Over the past eighteen (18) months California-based Faraday Future (FF)  has drawn an incredible hype with plans to “redefine the automotive experience by delivering seamlessly connected electric vehicles and future mobility solutions that will fit the needs of tomorrow’s population.”   Former automotive design-team leaders were recruited from BMW and Tesla Motors.   This Chinese-backed company has huge ambitions to change the future of the automotive industry and take on other electric rivals. Faraday says it is targeting the highest energy density and specific vehicle energy on the market with its battery pack. That would likely take the total energy capacity to over 100 kilowatt-hours, given Tesla’s recent announcement of a 90-kWh pack option for its Model S sedan.

FF plans to use a single pack design, smaller than current large packs to provide greater crumple zones, but will offer different pack capacities inside this single form factor. The batteries sit in horizontal rows, and the scalable factor of the platform comes from the ability to add or take away rows for different sized models. Nick Sampson, senior VP at FF and head of R&D said the batteries would operate like Christmas tree lights — if one pack goes out the “strand” keeps working. Other specifics–cells grouped into modules, replaceable cells or modules, safety measures to prevent any short in a faulty cell from propagating to adjacent cells–have been seen before in various other makers’ pack designs.

Are you ready for this one—“The 1,000-horsepower FFZero1 includes the ability to exceed 200mph (321 kph) and accelerate from zero to 60mph in less than three seconds. It also includes a helmet to provide oxygen and water to the driver.”  Other key features are as follows:

  • The adjustable chassis can accommodate strings of batteries that are more easily changed than single batteries. The number of batteries would depend on car size
  • A helmet to provide oxygen and water to the driver. (This really blows my mind.)
  • ‘Aero tunnels’ incorporated into the design to channel air through the vehicle for reducing drag and cooling the batteries.

Faraday made a deal with the State of Nevada for a billion dollar factory, securing over $330 million in tax incentives and eventually bringing 4,500 jobs to the state. FF revealed at CES (Consumer Electronic Show-2016)  plans to break ground on the new three million square-feet factory in just a few weeks, with the Mayor of North Las Vegas and Governor of Nevada present at the event.

Let’s take a look at the FFZERO1 displayed at the recent show.




As you can see, this is truly a car of the future and apparently that future begins in 2017. Please keep in mind, if this vehicle is commercialized at all, there will have to be involvement with the DOT.  Approvals will have to be given.  Maintenance protocols will have to be developed. Spare parts will have to be designated.  In other words, there is a great deal of extremely important work needing to be accomplished prior to the first vehicle being sold.  I may have missed it but I saw no price mentioned in any of the press releases for the product.  I suppose if you have to ask you cannot afford one.  Time will tell.


February 6, 2016

If you have read my posts in the recent past you know that I enjoy writing about technology and sustainability.  I make every effort, as time allows, to track technology and detail advances and discoveries that affect our lives.  I definitely try to “stay close” to all sustainability efforts regardless as to where they occur over our globe.  Let’s very quickly define “sustainability” as:

A state in which the demands placed on the environment can be met without reducing its capacity to allow all people to live well, now and in the future.”

Evidence suggests that we are exceeding and eroding the earth’s carrying capacity, that there are limits to growth on a finite planet.  Effects are interactive, complex, unpredictable and escalating, as we head for a global average temperature rise of more than 2 degrees centigrade over pre-industrial levels.

Sometimes ‘environmental’, ‘social’ and ‘economic’ are termed to be the three pillars of sustainability.  But this is problematic as it suggests they are equivalent and can be traded.  Environmental sustainability is the context within which social and economic life happen. Also, social inequity directly affects environmental viability.

Leading thinkers suggest that to stand any chance of achieving environmental sustainability, businesses need to move from a sense of right-to-exploit the natural environment to a worldview of mutual interdependence and radical eco-innovation.  Many organizations are now taking on this challenge.

One country, Morocco, has taken that definition very seriously and has accomplished a marvelous engineering feat.  OK, with that being the case, just where is Morocco? Morocco lies on the Northwestern portion of the African Continent. The two digital maps below will indicate the exact location for us.



The country of Morocco has officially turned on a massive solar power plant in the Sahara Desert, kicking off the first phase of a planned project to provide renewable energy to more than one million Moroccans.

The Noor I (Quarzazate Solar Power Station or OSPS) is located in the Souss-Massa-Drâa area of Morocco, 10 km from Ouarzazate town, in Ghessat rural council area.

It is capable of generating up to 160 megawatts of power and covers more than thirty-five (35) soccer fields of desert.  This fact signifies NOOR I as being one of the world’s largest solar thermal power plants.

There are two additional phases, Noor II and Noor III that will come on line with completion in 2030. With NOOR I, NOOR II and NOOR III active, Morocco will be able to generate 580 Mw and supply most of the nation’s power needs.

Morocco currently relies on imported sources for 97 percent of its energy consumption, according to the World Bank, which helped fund the Noor power plant project. Investing in renewable energy will make Morocco less reliant on those imports as well as reduce the nation’s long-term carbon emissions by millions of tons.

“It is a very, very significant project in Africa,” said Mafalda Duarte, the manager of Climate Investment Funds (CIF), which provided $435m (£300m) of the $9bn project’s funding. “Morocco is showing real leadership and bringing the cost of the technology down in the process.”

The digital photograph below will indicate the enormous size of the Saudi-built “footprint” upon which this energy will be derived.  Please keep in mind, this is only phase one of the overall project.   There are eight hundred (800) rows with five hundred thousand (500,000) collector panels in the overall array.  These panels track the sun as it moves from east to west.  The digital after the surface area indicates the basic configuration of the collector panels themselves.


Curvature of Panels

The system at Ouarzazate uses 12-meter-tall [39-foot-tall] parabolic mirrors to focus energy onto a fluid-filled pipeline.  The pipeline’s hot fluid — 393 degrees Celsius (739 degrees Fahrenheit) — is the heat source used to warm the water and make steam. The plant doesn’t stop delivering energy at nighttime or when clouds obscure the sun; heat from the fluid can be stored in a tank of molten salts.”  The facility is designed to provide energy twenty (20) hours per day.  The only down-time will be four hours in a twenty-four hour day.  The Noor II and Noor III plants will have a molten salt storage capacity of seven hours each, whereas Noor I will have a molten salt storage capacity of three hours.

Noor I will use a wet cooling system whereas the latter plants will use a dry cooling system. The water required for the plants will be sourced from the Mansour  Eddabhi dam, located approximately 12km from the project site, and stored in water storage reservoirs with a total capacity of 300,000m³.  Complexities of the overall mechanical system may be seen below.


The specifications for this remarkable project are as follows:



One striking fact—the Ouarzazate Solar System will reduce carbon emissions by 760,000 tons per year.  This is the definition of sustainable.

As always, I welcome  your comments.

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