Last week I promised to take a look at soil and stain repellant finishes to see how each is applied and/or formulated.  Some of these trademarked finishes claim impeccable green credentials, so it’s important that we are able to evaluate their claims – or at least know the jargon!  The chemistry here, as I said in last week’s post, is dense.  The important thing to remember about all these finishes is that they all depend on flurocarbon based chemistry to be effective.

The oldest water repellant finishes for fabrics were simply coatings of paraffin or wax – and they generally washed out eventually.  Perfluorochemicals (PFC’s) are the only chemicals capable of repelling water, oil and other liquids that cause stains. Fabrics finished with PFCs have nonstick properties; this family of chemicals is used in almost all the stain repellant finishes on the market today.  Other materials can be made to perform some of these functions but suffer when subjected to oil and are considerably less durable.

The earliest type of stain resistant finish (using these PFCs)  prevented the soil from penetrating the fiber by coating  the fiber. For use on a textile, the chemicals are joined onto binders (polyurethane or acrylic) that acts as a glue to stick them to the surface of the fabric.  Gore Tex is one of these early coatings – a thin film was laminated onto the fabric; another, manufactured by 3M Corporation for nearly 50 years,  is Scotchgard.   Scotchgard was so popular and became so ubiquitous that “Scotchgard” entered the language as a verb.  

The chemical originally used to make Scotchgard and Gore Tex breaks down into perfluorooctane sulfonate, or PFOS, a man-made substance that is part of the family of perfluorochemicals.   PFOS and PFOA have chains of eight carbon atoms; the group of materials related to PFOA and PFOS is called C8 –  this is often referred to as “C8 chemistry”.

An aside on C8 chemistry:

If you recall from last week’s post, the PFC family consists of molecules having a carbon backbone, fully surrounded by fluorine.  Various “cousins” have carbon backbones of different lengths:  PFOS or C8, for example,  has 8 carbon atoms, C7 has 7, and so on.  There is controversy today  about  the so-called  “bad” fluorocarbons (C8 ) and the “good” ones (C6) which I’ll address below.

C8  -  (the backbone  is made of a chain of 8 carbon atoms):  two methods are used to produce two slightly different products:

1)     electrofluorination:  uses electrolysis to replace hydrogen atoms in a molecule by fluorine atoms to create the 8 unit chain containing just carbon and fluorine.  A small amount of PFOS (perfluorooctane sulphonate) is created during this process.

2)     Telomerisation:  chemical equivalent of making a daisy chain: produces mini polymers by joining single units together in chains.  The usual aim is to produce chains that are an average of 8 units long, but the process is not perfect and a range of chain length will result – ranging from 4 units to 14 units in length. So you can have a C4, C6, C12, etc. In this method a small amount of byproduct called PFOA (perfluorooctanoic acid) is produced.

C6 – this chemistry produces a by-product called PFHA (perfluorohexanoic acid), which  is supposed to be 40 times less bioaccumulative than PFOA.  But it’s also less effective, so more of the chemical has to be used to achieve the same result.  Manufacturers are trying to find smaller and smaller perfluorocarbon segments in their products, and even C4 has been used.  The smaller the fluorocarbon, the more rapidly it breaks down in the environment.  Unfortunatley, the desired textile performance goes down as the size of the perfluorocarbon goes down. “C6 is closest chemically to C8, but it contains no PFOA. It breaks down in the environment – a positive trait – but it doesn’t stick as well to outerwear and it doesn’t repel water and oil as well as C8, which means it falls short of meeting a vague industry standard, as well as individual company standards for durability and repellency.”[1]

Back to Scotchgard:

Scientists noticed that PFOS (the C8 fluorocarbon) began showing up everywhere: in polar bears, dolphins, baby eagles, tap water and human blood. So did its C8 cousin PFOA.   These two man-made perfluorochemicals (PFOS and PFOA) don’t decompose in nature. They kill laboratory rats at higher doses, and there are potential links to tissue problems, developmental delays and some forms of cancer.  Below are tables of results which the U.S. Environmental Protection Agency released from data collected by 3M and DuPont; some humans have more PFOA in their blood than the estimated levels in animals in this study.  For a complete review of this study, see the Environmental Working Group’s website, http://www.ewg.org/node/21726.

PFOA and PFOS, according to the U.S. EPA:

• Are very persistent in the environment.
• Are found at very low levels both in the environment and in the blood of the U.S. population.
• Remain in people for a very long time.
• Cause developmental and other adverse effects in laboratory animals.

Eventually 3M discontinued Scotchgard production.  Yet accounts differ as to whether 3M voluntarily phased out the problematic C8 chemistry or was pressured into it by the EPA after the company shared its data in late 1999.  Either way, the phase-out was begun in December 2000, although 3M still makes small amounts of PFOA for its own use in Germany. 3M, which still monitors chemical plants in Cottage Grove, Decatur, and Antwerp, Belgium, insists there are no risks for employees who handled or were exposed to the chemicals.  Minnesota Public Radio published a timeline for milestones in 3M’s Scotchgard, which can be accessed here.

The phase-out went unnoticed by most consumers as 3M rapidly substituted another, less-effective spray for consumers, and began looking for a reformulated Scotchgard for carpet mills, apparel and upholstery manufacturers.   For its substitute, 3M settled on perfluorobutane sulfonate, or PFBS, a four-carbon cousin of the chemical in the old Scotchgard, as the building block for Scotchgard’s new generation. This new C4-based Scotchgard is completely safe, 3M says. The company adds that it has worked closely with the EPA and has performed more than 40 studies, which are confidential. Neither 3M nor the EPA will release them.

According to 3M, the results show that under federal EPA guidelines, PFBS isn’t toxic and doesn’t accumulate the way the old chemical did. It does persist in the environment, but 3M concluded that isn’t a problem if it isn’t accumulating or toxic. PFBS can enter the bloodstream of people and animals but “it’s eliminated very quickly” and does no harm at typical very low levels, said Michael Santoro, 3M’s director of Environmental Health, Safety & Regulatory Affairs. 3M limits sales to applications where emissions are low.

3M says convincing consumers Scotchgard is safe is not its No. 1 challenge; rather it’s simply getting the new, new Scotchgard out. The brand, 3M maintains, is untarnished. “This issue of safety, oddly enough, never registered on the customers’ radar screen,” said Michael Harnetty, vice president of 3M’s protective-materials division.

Scotchgard remains a powerful brand:  “We still get really good requests like, ‘Will you Scotchgard this fabric with Teflon?’ ” said Robert Beaty, V.P. of Sales for The Synthetic Group, a large finishing house.[2]

Another early soil resistant finish is Teflon, which was produced by DuPont.  Teflon is based on C8 chemistry, and PFOA is a byproduct of the manufacturing of fluorotelomers used in the Teflon chemistry.

There has been a lot of information on 3M, DuPont and these two products, Scotchgard and Teflon, on the web.  The Environmental Working Group  http://www.ewg.org/ has detailed descriptions of what these chemicals do to us, as well as the information on the many suits, countersuits, and research studies.  The companies say their new reformulated products are entirely safe – and other groups such as the Environmental Working Group, question this assumption.

By the way, both DuPont and 3M advertise their products as being “water based” – and they are, but that’s not the point and doesn’t address the critical issues.  In TerraChoice’s “Seven Sins of Greenwashing” this would be considered Sin #5: the sin of irrelevance, which is:  “An environmental claim that may be truthful but is unimportant or unhelpful for consumers seeking environmentally preferable products. ‘CFC-free’ is a common example, since it is a frequent claim despite the fact that CFCs are banned by law.”

In January 2006, the U.S. Environmental Protection Agency (EPA) approached the eight largest fluorocarbon producers and requested their participation in the 2010/15 PFOA Stewardship Program, and their commitment to reduce PFOA and related chemicals globally in both facility emissions and product content 95 percent by 2010, and 100 percent by 2015.

The fluoropolymer manufacturers are improving their processes and reducing their waste in order to reduce the amount of PFOA materials used. The amount  of PFOA in finishing formulations is greatly diminished and continues to go down, but even parts per trillion are detectable. Finishing formulators continue to evaluate new materials which can eliminate PFOA while maintaining performance but a solution is still over the horizon.  One critical piece in this puzzel is that PFOA is also produced indirectly through the gradual breakdown of fluorotelomers – so a stain resistant finish may be formulated with no detectable amounts of PFOA yet STILL produce PFOA when the chemicals begin to decompose.

Recently a new dimension was added to stain resistant formulations, and that is the use of nanotechnology.

Nanotechnology is defined as the precise manipulation of individual atoms and molecules to create layered structures. In the world of nanoscience, ordinary materials display unique properties at the nanoscale.  The basic premise is that properties can dramatically change when a substance’s size is reduced to the nanometer range. For example, ceramics which are normally brittle can be deformable when their size is reduced. In bulk form, gold is inert, however, once broken down into small clusters of atoms it becomes highly reactive.

Like any new technology, nanomaterials carry with them potential both for good and for harm. The most salient worries concern not apocalyptic visions,  but rather the more prosaic and likely possibility that some of these novel materials may turn out to be hazardous to our health or the environment.  As John D. Young and Jan Martel report in “The Rise and Fall of Nanobacteria,” even naturally occurring nanoparticulates can have an deleterious effect on the human body. If natural nanoparticulates can harm us, we would be wise to carefully consider the possible actions of engineered nanomaterials.  The size of nanoparticles also means that they can more readily escape into the environment and infiltrate deep into internal organs such as the lungs and liver. Adding to the concern, each nanomaterial is unique. Although researchers have conducted a number of studies on the health risks of individual materials, this scattershot approach cannot provide a comprehensive picture of the hazards—quantitative data on what materials, in what concentrations, affect the body over what timescales.

As a result of these concerns, in September, 2009,  the U.S. EPA  announced a study of the health and environmental effects of nanomaterials – a step many had been advocating for years.  And this isn’t happening any too soon:  more than 1,000 consumer products containing nanomaterials are available in the U.S. and more are added every day.

And nanotechnology has been used for textiles in many ways: at the fiber as well as the fabric level, providing an extraordinary array of nano-enabled textile products (most commonly nanofibers, nanocomposite fibers and nanocoated fibers)  – as well as in soil and stain resistance.

For scientists who were trying to apply nanotechnology to textile soil and stain repellency, they turned, as is often the case in science, to nature:  Studying the surface of lotus leaves, which have an incredible ability to repel water, scientists noticed that the surface of the lotus leaf appears smooth but is actually rough and naturally dirt and water repellent. The rough surface reduces the ability of water to spread out. Tiny crevices in the leaf’s surface trap air, preventing the water droplets from adhering to the service. As droplets roll off the surface they pick up particles of dirt lying in their path. Using this same concept, scientists developed a nanotechnology based finish that forms a similar structure on the fibers surface. Fabrics can be cleaned by simply rinsing with water.

Nano-Tex (www.nano-tex.com) was the first commercially available nanoparticle based soil repellant fabric finish.  It debuted in December of 2000.  Another nanotech based soil repellant is GreenShield (www.greenshieldfinish.com) which debuted in 2007. Both these finishes, although they use nanotechnology, also base their product on fluorocarbon chemistry.  Nano-Tex’s website does not give much information about their formulation – basically they only say that it’s a new technology that “fundamentally transforms each fiber through nanotechnology”.  You won’t get much more in the way of technical specifications out of Nano-Tex.   GreenShield is much more forthcoming with information about their process.

In the GreenShield finishes, the basic nanoparticle is amorphous silica, an inert material that has a well-established use in applications involving direct human consumption, and is generally recognized as safe and approved by the Food and Drug Administration (FDA) and Environmental Protection Agency for such applications.  The use of silica enables GreenShield to reduce the amount of flurocarbons by a factor of 8 or more from all other finishes and it reduces overall chemical load by a factor of three – making GreenShield the finish which uses the least amount of these flurocarbons.

The GreenShield finish gets mixed environmental ratings, however.   Victor Innovatix’s Eco Intelligent Polyester fabrics with GreenShield earned a Silver rating in the Cradle to Cradle program. However, the same textile without the GreenShield finish (or any finish) earned a higher Gold rating, reflecting the risk of toxicity introduced to the product by GreenShield. Information on product availability is at www.victor-innovatex.com.

[2] Bjorhus, Jennifer, “Scotchgard is Attractive Again”, St. Paul Pioneer Press, May 27, 2003

During the 2009 season I forced myself to keep the M3 as stock as possible. The M3 is a great platform for the track, a very “happy” and balanced car which needs little modifications to make it ready for serious HPDE events.

My goal was to do minimal upgrades and “learn how to drive the car as it is”. 98% of going faster during your first season is DRIVER UPGRADES…those come in the form of class room instruction and seat time with an experienced instructor.

During 2009 Build Upgrades included:

Performance Friction 2Piece Rotors
These 2rotors allow you to keep the hat and simply replace the rotor when it becomes worn. Initial cost is a bit higher and buying a 1 piece rotor&hat but over the longer haul by only having to replace the rotor component and reusing the hat rotor consumable cost is lowered.

Racing pads are a must once you start going quicker on the track. Stock rotors on any production car are setup to operate with high levels of “bite” even when they are cold, but used again and again to pull a car down from high speeds stock pads overheat causing brake fade and will eventually boil your stock brake fluid.

Racing Pads operate efficiently at much higher temperatures … the kinds of temperatures you find when you are really working the brakes hard. Image the energy it takes to slow a 3000lb car down from 140Mph to 40Mph. Brakes take that energy and turn it into heat… now that’s HOT!

I have tried both the PFC01 and PFC06 compound pads. The PFC01 is a very aggressive pad with a lot of bite. The PFC06 pad is nearly aggressive but is touted as an endurance pad … The PFC06 seems to last QUITE a bit longer than the PFC01. Also with street tires I had some issues keeping enough temperature in the PFC01 to keep them in their optimal operational range, didn’t have that problem with the PFC06.

Racing Brake Fluid
With higher brake pad and rotor temperatures in a track environment upgrading your brake fluid so it won’t boil is a must. If you boil your brake fluid, air bubbles are left in your brake lines and will leave you with a soft brake pedal, or worst case a brake pedal that goes all the way to the floor w/out slowing the car at all! The reason for this, fluids don’t compress much, air compresses A LOT! The force that squeezes the pads onto the rotors requires pressure in your brake system, w/out pressure or with air that compresses in your brake lines you don’t get much squeeze on the rotors from the pads. Not a situation you want when you are headed into a low speed corner coming down the main straight on the racetrack!

I chose Castrol SRF. It’s one of the best and has one of the highest boiling points of any brake fluid. At $80 liter it better be good!

Stainless Steel Brake Lines
As you can see, keeping pressure in your brake system is critical to the operation of your brakes. Most cars come with rubber brake lines, rubber when it gets hot will stretch or bulge. Replacing the rubber brake lines with Stainless Steel lines keeps this from happening and contributes to a good performing brake system.

Square Tire Setup
The E46 M3 like most commercial cars comes from the factory setup to understeer. Manufactures do this because they believe understeer is “safer” and easier to control and correct when it occurs, it is also more predictable than overstreer.

Understeer is when the front end of the car feels like it is getting pushed to the outside of the turn. Basically the car is not turning as sharp as you have the wheel turned due to lack of traction. Understeer is easy to correct by a) slowing down a bit, or b) opening the wheel so you are turning less.

The stock setup of the E46 M3 causes the car to understeer both when entering a corner and when exiting. On the track that becomes a nuisance and a performance limiter unless something is changed.

One of the easiest ways to compensate for the undesirable and excessive understeer setup of the E46 is to replace the front wheels and tires with the same size wheels and tires you are running on the rear of the car. Trackers call this a “square setup”.

Instead of 225/45/18 sized front and 255/40/18 sized rear tire (staggered setup), you end up with a 255/40/18 sized tire setup on all four wheels. The extra grip provided by the 255 tire compared to the stock 225 does a good job of eliminating a lot of the factory understeer and really makes the car feel good on “turn in” (when turning into a corner).

–
Other than some minor cosmetic enhancements those upgrades above served me very well for my first season, I would recommend anyone new to HPDE with an M3 consider the same upgrades.

Uf, por fin le ha gustado alguno de mis dibujos al tutor (oh, señor todopoderoso, más comúnmente conocido como Javier Peña).

Aquí os dejo lo que le he enseñado hoy, aunque todavía queda realizarle varios retoques para hacerlo más presentable.

La planta baja

Una sección en perspectiva

A ver qué os parecen.

Seguramente esta pregunta nos la hacemos todos los ingenieros cuando nos llega la hora de comenzar el Proyecto Fin de Carrera (PFC). Una de las cosas que aprendí de la asignatura de Proyectos, es que tener claros los objetivos y planificación del mismo es un punto muy importante si queremos garantizar el éxito. Cambiar de objetivos en mitad del desarrollo es algo muy costoso y muchas veces hasta resulta inviable.

Por este motivo, debemos empezar por ahí, por fijar los objetivos y tomar decisiones que sean claves para el desarrollo del proyecto. Aunque también es cierto que si nos podemos permitir el lujo de probar antes de tomar una elección, esto siempre nos ayudará a decidirnos.
Bien, mi proyecto se basará en OpenCV, estará escrito en C/C++ y ejecutable en la plataforma GNU/Linux.

OpenCV es un conjunto de herramientas para el tratamiento de imágenes en tiempo real sobre ordenadores orientado a visión artificial. Es decir, OpenCV nos ofrece facilidad para operaciones típicas de este campo como pueden ser la detección de objetos, el seguimiento de objetos, reconocimiento facial, etc.

OpenCV está escrito en C/C++ y optimizado para su uso en tiempo real, pudiendo mejorar su rendimiento con las Primitivas de Rendimiento Integradas de Intel ( IPP, específicas para procesadores Intel) que no son libres, sino que Intel las vende para fines comerciales.

Se puede trabajar con OpenCV con varios lenguajes de programación como Python a través de bindings, pero se recomienda C/C++.

A lo largo del desarrollo del proyecto volveremos a hablar de OpenCV.

President Barack Obama leaves a Presidential coin at the gravesite of 19-year-old Medal of Honor recipient, Specialist Ross McGinnis, who is one of two Medal of Honor recipients memorialized at the cemetery from the wars in Iraq and Afghanistan.

Daily News/James Gordon Meek—He didn’t introduce himself. He didn’t have to.

President Obama simply stuck out his hand and asked for my name as he stepped toward me amid a bone-chilling drizzle in the Gardens of Stone.

This was Section 60 of Arlington National Cemetery. I wasn’t there as a reporter, but to visit some friends and family buried there when Obama made an unscheduled stop – a rare presidential walk among what Lincoln called America’s “honored dead” – after laying a Veterans Day wreath at the Tomb of the Unknowns.

President Obama extends a hand to James Gordon Meek of the Daily News Washington Bureau.

What I got was an unexpected look into the eyes of a man who intertwined his roles as commander in chief and consoler in chief on a solemn day filled with remembrance and respect for sacrifices made – and sacrifices yet to be made.

I’m sure the cynics will assume this was just another Obama photoop.

If they’d been standing in my boots looking him in the eye, they would have surely choked on their bile.

His presence in Section 60 convinced me that he now carries the heavy burden of command.

I had stopped at Arlington to see the resting place of Ken Taylor, Ed Lenard and Dave Sharrett. Ken and Ed survived their service, in World War II and Korea, and died as old men. Dave did not leave Iraq alive. He was 27.

Obama arrived just before noon at the serene Section 60, where many of the dead from Iraq and Afghanistan are buried together – and where many more heroes will undoubtedly be laid to rest before this President leaves office.

It’s a section typically bustling with those visiting loved ones. Every time I go there, more and more graves have been dug into the earth.

The President and First Lady Michelle Obama emerged from their armored limousine hatless in the frigid downpour and took a slow stroll into the soggy rows of white marble headstones.

They stopped first at the grave of Medal of Honor recipient Ross McGinnis, an Army private who threw himself on a grenade in Iraq three years ago to save four buddies.

A sad-faced woman reached for Obama’s hand and pointed him to a nearby plot.

The face of another woman – who had grimly sat in a folding chair for hours next to a headstone she’d arranged flowers around – suddenly broadened into a smile as she stood to embrace Obama and thank him for paying his respects.

She was so overcome with emotion that a soldier from the Army’s Old Guard had to console her afterward.

Gravestone of Pfc. David Sharrett at Arlington National Cemetery

The President patted backs of a dozen other Gold Star relatives and troops visiting buddies now in the ground.

He gave hugs. He shook wet, chilly hands. He wanted to know something about each fallen warrior.

He began to slowly trudge back toward the motorcade – and to another White House huddle with his war council, which is advising him whether to send up to 40,000 additional troops into harm’s way in Afghanistan.

And then Obama noticed a tall, bearded figure. He probably didn’t see the mud-caked combat boots I trudged around Afghanistan in a few years ago.

“What’s your name?” a somber President asked as he extended his hand.

“James Meek, sir,” I replied, struggling to pull off my wool glove and pull my hood back from my head. “I’m here visiting a friend, Pfc. David H. Sharrett II, who was killed in Iraq last year.”

More @

Con esta entrada queda inaugurado el blog LanderPFC en el que escribiré acerca de mis avances, dudas o problemas que surjan en la elaboración de mi Proyecto Fin de Carrera.

El Proyecto Fin de Carrera está incluido en mi plan de estudios como una asignatura de 3º de Ingeniería Técnica de Telecomunicaciones, especialidad Sonido e Imagen.

A grandes rasgos el proyecto se basa en crear un programa informático que sea capaz de analizar las imágenes que le llegan desde una webcam y hacer seguimiento (tracking) de un color destacable de forma que creemos una especie de pizarra virtual. Este tipo de proyectos pertenece al área de la realidad aumentada (AR), y usará las librería de código abierto OpenCV diseñadas para visión por ordenador, con un sinfín de aplicaciones.

Dentro de los departamentos de la Universidad de Extremadura (UNEX), este proyecto pertenece al de Teoría de la Señal y Comunicaciones (TSC) y mi tutor del proyecto es Pedro Núñez.

¡De momento esto es todo pues acabo de comenzar!

Skip the Non-Stick

Non-stick cookware has been popular because, well, it’s non-stick — very convenient to use and clean. But it also emits toxic fumes when overheated. Environmental Working Group recommends that you choose safer cookware to reduce the risk of inhaling toxic particles when you let that non-stick pan get a little too hot. And who doesn’t do that occasionally?

• Why you should skip the non-stick
• What safer cookware to choose
• How to cook with non-stick if you’re ’stuck’ with it
• Other ways people are exposed to PFCs, and how to avoid them

Non-stick surfaces are aluminum pans coated with a synthetic called polytetrafluoroetheylene (PTFE), also known as Teflon, a DuPont brand trademark. Learn more about Teflon and its perfluorinated chemical “family” (PFC’s) in our chemical dictionary.

Toxic fumes from the Teflon chemical are released from pots and pans at high temperatures, potentially killing pet birds and causing people to exhibit flu-like symptoms (called “Teflon Flu” or, as scientists describe it, “Polymer fume fever”). Ingesting particles that flake off scratched non-stick cookware isn’t toxic because solid PTFE flakes are inert.

Manufacturers’ labels often warn consumers to avoid high heat when cooking on Teflon. But EWG-commissioned tests conducted in 2003 showed that in just two to five minutes on a conventional stove top, cookware coated with Teflon and other non-stick surfaces could exceed temperatures at which the coating breaks apart and emits toxic particles and gases.

See a graphic of what happens at to Teflon at various temperatures.

Health dangers: When you breathe kitchen air polluted with fumes from overheated Teflon, you’re at risk for developing flu-like symptoms (yes, “Teflon flu”). The long-term effects of routine exposure to Teflon fumes, and from Teflon flu itself, have not been adequately studied.
PFCs have been found in nearly all Americans tested by federal public health officials. Chemicals from this family are associated with smaller birth weight and size in newborn babies, elevated cholesterol, abnormal thyroid hormone levels, liver inflammation and weakened immune defense against disease.

Environmental hazards: Manufacturing PFCs and the consumer products that contain them poses great risks to the environment and wildlife. The U.S. Environmental Protection Agency says PFCs present “persistence, bioaccumulation, and toxicity properties to an extraordinary degree.”

While there are a growing number of new cookware options on the market, we don’t know enough about them to know if they’re safe — even if they’re advertised as “green” or “not non-stick.” We continue to recommend cast iron and stainless steel cookware as safer options for stove-top cooking, and oven-safe glass for baking. These safer pans might be a little harder to clean, but your health is worth it.

Stainless steel is a terrific alternative to a non-stick cooking surface. Most chefs agree that stainless steel browns foods better than non-stick surfaces.
Cast iron remains a great alternative to non-stick cooking surfaces. Lodge, America’s oldest family-owned cookware manufacturer, refers to its cookware as “natural non-stick.” Cast iron is extremely durable and can be pre-heated to temperatures that will brown meat and will withstand oven temperatures well above what is considered safe for non-stick pans.

• Never preheat nonstick cookware at high heat — empty pans can rapidly reach high temperatures. Heat at the lowest temperature possible to cook your food safely.
• Don’t put nonstick cookware in an oven hotter than 500 degrees.
• Use an exhaust fan over the stove.
• Keep pet birds out of the kitchen — the fumes from an overheated pan can kill a bird in seconds. Learn more here.
• Skip the self-cleaning function on your oven. It cleans by heating to high temperatures, which can release toxic fumes from non-stick interior oven parts.
• Choose a safer alternative when buying new cookware.

PFCs are ubiquitous — both in and out of the kitchen. They are widely used as water, stain and grease repellents for food wrap, carpeting, furniture, and clothing. They keep food from sticking to pots and pans, repel stains on furniture and rugs, and make the rain roll off raincoats.

If you want to avoid PFCs in more places than your cookware, download our Guide to PFCs to reduce your exposures further.

Original Post by Environmental Working Group.

Los métodos que he implementado para poder repartir el costoso cálculo en varios ordenadores, con sus respectivas tarjetas graficas, son los siguientes:

Varios ordenadores compartiendo los cálculos cada vez que realizan un subset:

Un servidor que coordina todos los calculos que realiza cada nodo:

By all accounts, Steve Blackman pulled off a well executed event. The Zembo Shrine was packed and primed for Harrisburg’s first MMA event. Only 1 of the 13 fights that went down went to the cards, and that was a split decision. Looks like we missed a hell of a night.

Amateur Fights
Justin Lucas defeats Bradley Herrick (KO) @ :07 R2
Herrick: 45 day medical suspension

Darrell Horcher defeats Shawn Harris (KO) @ :37 R1
Harris: 90 day medical suspension

Kevin Flinchbaugh defeats Joshua Gieringer (TKO) @ :38 R1
Gieringer: 30 day medical suspension

Matthew Pape defeats Matthew Pender (Split Decision)

Collin Sharpe defeats Nick Strebig (Submission/Armbar) @ 1:12 R1

Professional Fights
Isiah Larson defeats John Doyle (Submission/Armbar) @ 2:00 R2

Bryan Keller defeats Gabriel Walbridge (Submission/Guillotine) @ 2:29 R1

Jay Haas defeats Michael Bunyamanhop (TKO) @ 1:56 R1
Bunyamanhop: 45 day medical suspension

Anthony Leone defeats Dustin Pague (Submission/North-South Choke) @ 4:58 R2
Pague: 30 day medical suspension

Dennis Bermudez defeats Chris Conner (TKO) @ 4:01 R1
Conner: 45 day medical suspension

Mike Geurin defeats Boris Rakita (Submission/Guillotine) @ 2:11 R1

Devin Derrico defeats Terrill Leech (Submission/North-South Choke) @ 1:44 R1
Leech: 30 day medical suspension

Jeff Smith defeats Ric Humphries (Submission/Guillotine) @ 2:10 R1

Ted Czech had partial results of Friday’s PA Fighting Championships.

Jay Haas defeats Michael Bunyamanhop (TKO)
Kevin Flinchbaugh defeats Joshua Greiringer (TKO) @ :38 R1
Justin Lucas defeats Brad Herrick (KO)
Jeff Smith defeats Ric Humphries (Submission/Guillotine) R1
Anthony Leone defeats Dustin Pague (Submission/North-South Choke) R2

Full results coming as soon as the PSAC updates their results. These results are unofficial until confirmed by the PA State Athletic Commission.

Ted got some help from Tap or Sleep’s Jerod Phillips. Thanks to both for getting some results up.