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A simple method for the production or synthesis of carbon nanotubes as free-standing films or nanotube mats by the thermal decomposition of transition metal complexed alkynes with aryl, alkyl, alkenyl, or alkynyl substituents. In particular, transition metal (e.g. Co, Ni, Fe, Mo) complexes of diarylacetylenes, e.g. diphenylacetylene, and solid mixtures of these complexes with suitable, additional carbon sources are heated in a vessel. More specifically, the heating of the transition metal complex is completed at a temperature between 400-800° C. and more particularly 550-700° C. for between 0.1 to 24 hours and more particularly 0.5-3 hours in a sealed vessel under a partial pressure of argon or helium.
1. A method of preparing carbon nanotubes, comprising heating a precursor comprising a transition metal complexed alkyne in a sealed vessel.
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where each of R1, R2 is an aryl, alkyl, alkenyl, or alkynyl substituent
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17. Carbon nanotubes prepared by the method of
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19. Carbon nanotubes prepared by the method of
20. Nano-sized metal particles prepared by the method of
[0001] This application claims priority of Provisional Application Ser. No. 60/325,988 filed Sep. 28, 2001.
[0002] The United States Government has rights in this invention pursuant to Contract No. DE-AC03-76SF00098 between the United States Department of Energy and the University of California.
[0003] The present invention relates generally to methods for the production of carbon nanotubes, and more particularly to methods for the production of carbon nanotubes as free-standing films or nanotube mats by the thermal decomposition of transition metal complexes.
[0004] Carbon nanotubes, first reported by Iijima, have metallic electrical conductivity in the arm-chair configuration and are semi-conducting in a zig-zag structure. Because of the unique physical and chemical properties arising from their structure and size, they have potential applications in devices requiring efficient field emitters, high-strength fibers, strong radiation shields, energy absorbing materials, nano-scale catalytic beds, efficient gas storage, nano-circuits, nano-scale transistors, charge storage materials and white light sources. In addition, they also have potential applications as nano-sized, frictionless bearings, in the construction of nano-mechanical devices, electromechanical devices and opto-electronic devices. For most of these applications, it is desirable to synthesize nanotubes of high purity over a large area in film form. Control of diameter, morphology and lengths of the carbon nanotubes produced is also a useful requirement for practical applications of a particular process. In addition, simplicity and flexibility in the production and fabrication of carbon nanotubes will make a process commercially attractive.
[0005] Available carbon nanotube synthesis methods include arc discharge, laser ablation, and chemical vapor deposition (CVD) processes and variations of all these procedures. While the first two methods involve the breakage of graphite to carbon clusters and re-building of carbon nanostructures, the CVD process builds up the carbon nanotubes starting from smaller components. This difference directly relates to the efficiency of the processes with the CVD process being more efficient. Some of the reported CVD processes are economical, efficient and said to result in oriented films of nanotubes with the possibility of control of their diameter and lengths. The CVD and related processes involve the use of a metal catalyst (usually a transition metal) either pre-made on a support or made by in situ reduction of a suitable precursor and a carbon source in the form of a gas or vapor at high temperatures. Alternatively, a mixture of a carbon source (such as benzene, toluene or xylene) and a transition metal catalyst (such as ferrocene or nickelocene) as a metal source is pyrolyzed to produce nanotubes. These two general methods need high temperatures (typically >1000° C.) to produce the necessary catalytic particles.
[0006] Some of the drawbacks in the existing methods can be summarized as follows: 1. Lack of control/determination of metal (catalyst)/carbon (precursor) ratios in the starting materials and/or in the products. 2. Required fabrication of specialized apparatus. 3. Limited area coverage of nanotube mats. 4. Control of morphology of the produced nanotubes. 5. Lack of control in the yields of undesired side products, such as carbon onions and amorphous carbon. 6. High temperatures involved.
[0007] Accordingly it is desirable to provide an improved method of producing carbon nanotubes, particularly as free-standing films or nanotube mats. It is also desirable to provide a carbon nanotube fabrication method which reduces or eliminates the prior art process problems described above.
[0008] Accordingly it is an object of the invention to provide an improved method for fabricating carbon nanotubes.
[0009] Another object of the invention is to reduce the amorphous carbon content and carbon onions, and maximize the graphitized areas in the carbon nanotube product.
[0010] Yet another object of the invention is to produce transition metal particles for use in catalysis.
[0011] An additional object of the present invention is to simplify the production and fabrication of high quality nanotubes in the form of a film.
[0012] It is also an object of the present invention to provide a carbon nanotube fabrication method having a precise way to control metal/carbon ratios in the starting composition and the end products with the additional object of achieving the lowest possible metal/carbon ratios at the lowest possible temperatures.
[0013] The invention is a simple method for the production or synthesis of carbon nanotubes as free-standing films or nanotube mats by the thermal decomposition of transition metal complexed alkynes with aryl, alkyl, alkenyl, or alkynyl substituents, and solid mixtures of these complexes with suitable, additional carbon sources. One preferred embodiment is heating transition metal complexes of diarylacetylenes, e.g. diphenylacetylene, in a vessel. More specifically, the heating of the transition metal complex is completed at a temperature between 400-800° C. and more particularly 550-700° C. for between 0.1 to 24 hours and more particularly 0.5-3 hours in a sealed, vessel under a partial pressure of argon or helium. This heating results in the formation of carbon nanotubes, as free-standing films, in high yields. Removal of metal from these films, where necessary, is achieved by simply immersing the film in aqueous hydrochloric acid and the subsequent filtration of the dissolved metal.
[0014]FIG. 1 is a photographic image of a film formed inside a quartz tube by the thermolysis of a carbon nanotube precursor according to the invention.
[0015]FIG. 2 is a low magnification, transmission electron micrograph of a film showing the abundance of nanotubes produced by the invention.
[0016]FIG. 3 is an X-ray diffraction pattern of a nanotube mat produced by the invention, showing the highly graphitized nature of the film and the crystalline nature of the metal (cobalt) present.
[0017]FIGS. 4 and 4a are very low magnification scanning electron micrographs of the surface of the nanotube film showing the continuous occurrence of nanotubes.
[0018]FIG. 5 is a higher magnification scanning micrograph of a nanotube mat revealing the presence of very long (>100 μm) nanotubes.
[0019]FIG. 6 is a high magnification, high-resolution, transmission electron micrograph of a carbon nanotube present in a film such as shown in FIG. 4.
[0020]FIG. 7 is a spatially resolved (<5 nm) energy dispersion spectrum of a nanotube containing a nickel particle and FIG. 7a is a high resolution micrograph showing the fcc nickel particle present.
[0021]FIG. 8a shows a cobalt-diphenylacetylene complex which can be used as a nanotube precursor, and FIG. 8b shows a nickel compound which can be reacted with diphenylacetylene to form a nanotube precursor.
[0022] In accordance with the present invention, high quality, long carbon nanotubes, with narrow diameter distribution, can be prepared by heating transition metal complexed alkynes with aryl, alkyl, alkenyl, or alkynyl substituents in a sealed vessel. Preferably, before the heating, a weighed amount of the precursor complex is sealed in an atmosphere of an inert gas, preferably argon or helium, preferably at a pressure of about 20 mTorr, in a quartz vessel. The quartz vessel is then, preferably, maintained at a temperature of approximately 400-800° C. and more preferably at 550-700° C. for between 0.1 to 24 hours and more preferably 0.5-3 hours.
[0023] The invention utilizes alkynes having the general formula:
[0024] where each of R1, R2 is an aryl, alkyl, alkenyl, or alkynyl substituent. Illustrative compounds are: diphenylacetylene; 1-phenylpentyne; hexaethynylbenzene; and trans-4-phenyl-2-buten-1-yne.
[0025] The precursor materials are in the form of transition metal (including Co, Ni, Fe, Mo) complexes of alkynes (including diphenylacetylene and its derivatives). The complexes can be separately produced and isolated before use in the fabrication of the nanotubes, or they can be prepared in situ during the production of the nanotubes. Unlike other procedures known to date, since the elemental composition and precise structure of the starting complex is well established, the metal/carbon ratio of the precursor is predetermined accurately.
[0026] The nanotubes thus produced are in the form of free standing films (or nanomats) that can be simply lifted off from the inside of the vessel. Advantageously, coverage of areas more than 4 cm2 can be achieved from about 30 mg of the starting complex. A film produced by this method is shown in FIG. 1.
[0027] In the production of the nanotubes from the metal complexed alkynes, most of the metal stays outside the nanotubes and is relatively easily washed away by acid. However, some of the metal, typically about 15%, is deposited inside the nanotubes in the form of crystalline metal nanoparticles. These metal nanoparticles may be used for catalysis applications. The metal nanoparticles may also be removed from the nanotubes by further acid treatment.
[0028] Conventional quantitative chemical analytical techniques as well as energy dispersion spectra in an electron microscope were used to analyze the products obtained, in order to determine the elemental compositions. Thus the elemental composition of the bulk product is also clearly ascertained. Solid state analyses of the as prepared nanomats, including low-magnification transmission electron microscopy (FIG. 2), X-ray diffraction (FIG. 3), and scanning electron microscopy (SEM) (FIGS. 4, 4a, 5) revealed an abundance of nanotubes and their highly graphitized nature. Further analyses by high-resolution transmission electron microscopy (HRTEM) and spatially resolved, energy dispersion spectroscopy (EDS) revealed the graphitic internal structure of the nanotubes and the metal nanoparticles present encapsulated inside the tubes (FIGS. 6, 7 and 7 a).
[0029] Amorphous carbon forms or planar graphitic areas increased when the thermolyses of the complexes were carried out below or above the optimal temperatures. These results, in accordance with another aspect of the invention, provided nanosized metal particles useful in catalysis.
[0030] From the detailed analyses of the nature of the metal nanoparticles formed in the product, catalytically useful materials were identified. For example, starting with the cobalt complex of Example 1 as the precursor, under optimal conditions, cobalt nanoparticles with narrow diameter distribution were produced. Since the cobalt particles are produced free of carbides, and with the kinetically active cubic structure (fcc) as opposed to the thermodynamically favored hexagonal structure (hcp), they are useful in catalysis. These nanoparticles, since they are encapsulated in a carbon matrix, do not interconvert from fcc to hcp, upon standing (>1 year) and/or thermal annealing (under both these conditions, cobalt fcc particles produced by other known methods spontaneously convert to the more stable hcp structures).
[0031] The following examples illustrate, but do not limit, the invention.
[0032] The cobalt complex 1 shown in FIG. 8a (Bull. Soc. Chim. Belg. 563 (1987) 96), prepared in a single step from commercial diphenylacetylene and dicobaltoctacarbonyl [Co2(CO)8] can be used. Nickel complexes derived in situ from the commercial nickel(1,5-cylcooctadiene)2 [Ni(cod)2] 2 shown in FIG. 8b and diphenylacetylene can also be used. Upon heating, these complexes furnished free standing films made of nanotubes. Specifically, the heating of the transition metal complex is completed at a temperature between 400-800° C. and more particularly 550-700° C. for between 0.1 to 24 hours and more particularly 0.5-3 hours in a sealed vessel under a partial pressure of argon or helium.
[0033] The structure of the films was analyzed in bulk by X-ray diffraction, SEM and HRTEM. X-ray analysis revealed the highly graphitized nature of the film, the characteristic graphite inter-planar distance at 3.4 Å, and the absence of amorphous carbon structures. The surface of the film showed the abundance of carbon nanotubes when probed by SEM. SEM also identified the lengths of the nanotubes thus produced at >100 μm. HRTEM examination of the film further supported the results obtained from X-ray and SEM and showed the presence of nanotubes and the remarkable absence of amorphous carbon structures. Careful HRTEM imaging of several hundred nanotubes showed that the nanotubes had an average diameter distribution of 20-30 nm. Some of the tubes had encapsulated metal nano-particles present. These were unambiguously characterized by spatially resolved EDS (with ˜1 nm resolution) and HRTEM as single crystals of metal (e.g. Co, Ni). No metal carbides were detected. Since the precise composition of the starting complex is very well determined, the elemental composition of the precursor is predetermined. For example, in the case of the complex 1, the metal/carbon ratio is at 0.49. The resultant soot as a result had 40% cobalt, which was experimentally confirmed by quantitative EDS. Treatment of the film with concentrated HCl removed some of the metal present outside the nanotubes that by conventional quantitative chemical analysis was determined to be 25%. Hence, by acid treatment the metal content in the soot sample was reduced to 15%. Complexes with metal/carbon ratios as low as 11% were identified as suitable precursors. Thus, one of the objectives of this invention, namely, the precise control of metal/carbon ratios in the starting precursor and the product, was achieved (control of metal/carbon ratio is generally difficult to achieve as is well known in the art). More favorable metal/carbon ratios, corresponding to <5%, even without acid treatment, were also achieved as shown in the following.
[0034] In accordance with the present invention, additional carbon sources together with the complexes described above were also found to give carbon nanotubes. For example, hexaphenylbenzene when mixed with transition metal alkyne complexes acted as a suitable precursor for carbon nanotubes. Advantageously, such a modification also acted as a controlling factor for the lengths of nanotubes prepared, with nanotubes produced having lengths at <5 μm. Thus by choosing a suitable complex and carbon source, metal/carbon ratios of <5% were successfully achieved.
[0035] Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appended claims.
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Turmeric 101
What does living more naturally mean to you? Many of us with dieter mentalities know that often eating more "clean" and "pure" (read: more all natural) can benefit our health as much as cutting down on portion sizes and total calories consumed. Similarly, going all natural can pertain to other areas of our lives — as we try to get and stay healthier without a lot of overly-processed, unnatural ingredient-filled medication and remedies. Thus, turning to "nature's medicine cabinet" can often help out with a number of common ailments. One such go-to item is Turmeric, which is mostly known as the main spice that's used in curry. But the Turmeric root is often used for medicinal purposes.
From digestion troubles to healing wounds, Chinese and Indian medicine practices have been using Turmeric since the seventh century A.D. Today, more and more research is being done to understand the health benefits Turmeric may have. Turmeric is made from the dried rhizome's of the Turmeric plant. It's available in many different forms such as tea, powdered spice and as a capsule. Below is a handy infographic from Health Perch which shows off more about the Turmeric plant and how it can benefit you.
Do you use Turmeric to enhance your health and/or your life? If so, share your uses (and ideas) below in the comments section. (Thanks!)
Photo Source: Health Perch
What did you have for breakfast the day before yesterday? Do you remember? And aside from what you actually ate, how did you actually eat it? Or were you so rushed to get your day started that you skipped breakfast on that day all together?
Too often in our multitasking-oriented society, we rob ourselves of the quiet moments in life that we not only deserve but require. And for those of us with a dieter's mentality, this can be especially destructive. Fact is, if we ate more mindfully, many of us wouldn't even need an actual diet plan to lose excess weight and feel better about ourselves and our bodies in the present moment.
Don't get me wrong. I'm not knocking diet plans all together. When I weighed over 450 pounds, I was so out of touch with healthy eating (as were my body's "hungry" or "full" sensors), that I required an actual plan (based on sound nutrition and pure, clean eating) to head in the right direction (in my case, down the scale). But my weight loss success (dropping more than 250 pounds within a year's period without fad dieting, pills or surgery) came more from mindful eating than it did a so-called diet.
Learning to pay attention to what tasted good (sans additives, preservatives and other potentially harmful chemicals) and paying heed to how my body felt after a meal, led me to being more mindful about almost every aspect of my life — from exercise to walking my dog to even being more present when talking to someone on the phone (e.g., no more checking facebook on my smartphone while on a phone call, listening to my mother-in-law tell me how a recent doctor's appointment went).
Me. In the now. And being aware of it. Crazy concept, right?
And yet mindfulness doesn't have to be a mystery that we spend a lifetime trying to decipher. True mindfulness is simply about being fully present in the moment. That means being still and recognizing everything going on around us and being fully aware of it all.
Take a moment to stop reading this blog post, and just sit still (or stand still — reader's choice). Feel the cushion of the chair beneath you? The comfort of the seat back? The hardwood floor underneath your shoes? Or maybe whatever you're sitting or standing on isn't so comfortable. You might be reading this while on a subway train. Or while standing in line. Or perhaps while lying down.
Notice the elements surrounding you at this moment. Is there a clock ticking? Is someone talking loudly nearby? Can you feel the heat of the sun? Or maybe a cool breeze? Whatever is going on around you, take note of it. Soak it in. It's not bad. It's not good. It simply is. And now you get a gold star for noticing what's happening around you, being aware of your surroundings, and taking it all in.
Next, turn to your breathing. Are your breaths short and shallow, perhaps signaling that you're anxious about something? Or are they soft and deep? Maybe your calm breathing is letting you know that you're very confident, that life is good (even with all the many challenges you're facing), and that you know you are enough, in this moment.
Let's now take this fully aware mental state and apply it to our eating. All of our eating. That means being as mindful when we're planning or preparing what we're going to eat as when we're sitting down to actually consume the food. (Yes, sitting down! Eating at the kitchen counter while on the go doesn't often compliment being mindful.)
Too often the choices we make about food have less to do with what we're really craving (whether regarding a specific food or even a portion size) and more about what is habitual. Our routines can turn us into zombies. And living life like The Walking Dead is no way to… Well… Live.
This is now. And since this moment is all we really have, we might as well choose to enjoy it — and all of life's subsequent moments — fully. As we learn to embrace the now, we can allow ourselves to make choices about our food, our eating, and our self-acceptance that can literally transform life around us — and, perhaps, even transform our bodies in beautifully positive and healthy ways.
Photo Source: Existential Soft Rock
Can one small change bring big rewards?
Those who know me will tell you I'm a big caffeine addict. Granted, I treat caffeine (in the form of coffee) with the same regard I treat all food and drink in my life: With moderation. But "Back in the day," having coffee meant having a whole lotta cream and sugar with it. Actually, way back when (or weigh back when, as I like to say), I would drink coffee with artificial sweetener and artificial, nonfat creamer. The thought of consuming these totally unnatural, chemically altered substances make me shudder today.
As I learned more about health and nutrition, I gave those artificial substances up when drinking coffee. And I replaced them with real sugar (Sugar in the Raw was my choice) and real cream (Half N' Half in this case). You might be surprised to read about the sugar and Half N' Half. But based on how my body metabolized these more natural substances, I knew they were better for me than the artificial "fat and calorie free" crap (key word) that I'd been using up until then.
One. Small. Change.
But wait. There's more.
Having succeeded with my "Small change, big reward" theory with the artificial sweetener and cream, there was a day I decided to take it one step further. Thus, I gave up the cream and sugar entirely and, instead, started to drink my coffee au natural (AKA "Black"). This took some getting used to because I like my coffee strong and bold. So the first couple sips of black coffee would elicit the kind of facial expressions that not even graduates of clown colleges could make.
But eventually? I got used the taste of black coffee. And – surprise, surprise – I even began to prefer the taste of black coffee. I liked how the flavor worked in tandem with my morning cereal or toast (never overwhelming the taste of breakfast and never being overly sweet like a milkshake). Another small change. Not to mention another big reward in that I had reduced my calorie intake by no longer having cream and sugar with my coffee.
For a time, I would allow myself to have cream and sugar on special occasions. At first only on weekends. Then only on special occasions (like my birthday). But eventually? I went all black coffee, all the time. And since then, I've never looked back. Although I do still occasionally make the ridiculous clown faces during the first, somewhat bitter sips. But I've learned to enjoy that moment for what it's worth, figuring these 'facial exercises' might be burning up a few additional calories.
The great thing about small changes is that once you've successfully achieved them and made them part of your life, they will start to affect other decisions. For example, if I'm running around town and have to grab breakfast on the run, if I'm getting a black coffee I don't want to completely negate that healthy choice by having a donut with it and instead will opt for a bran muffin or piece of fruit. Again, everything in moderation.
Now, I'm not telling you to join me on the black coffee bandwagon. But I'm am suggesting you look at different areas of your life and see where there might be room for one small change. Accomplishing that change could affect the rest of your life – and perhaps your health – in a positive, beautiful way.
Planning a small change? Or have an accomplished change to brag about? Do tell! I'm waiting over my cup of coffee with bated breath (and a promise not to react with a 'clown face').
Beating stress at its own game
No matter how much we plan in advance or mentally prepare, life is going to sometimes bring stress our way (in all sorts of different forms – many of which can't be predicted). The trick to not being eaten alive by this stress (which, in turn, often makes us want to eat everything in our path), is to not let the stressful events give us an excuse to cheat on our diets, yell at the people closest to us or to let the rest of our day (or week!) be ruined. Stress is on its way. Bank on it. The trick is accepting it, dealing with it and moving past it.
Here are a few practical tips for keeping stress in its place:
Learn from the stress:
Yeah, I know this can sound a bit trite. But a lot of times there is a good lesson to be learned from stressful situations. Sure this 'learning' usually happens long after the stress has come and gone. But putting a positive spin on what occurred and seeing away to avoid and/or handle the same stressful situation in the future is a valuable lesson. For ideas about how to gain helpful insights from stress, click here.
Breathe Deep:
Controlled breathing can be like a "Mini Meditation" and help us to change the mental channel by getting more in touch (and in control) of what's going on with ourselves, internally. Helpful breathing exercises can be found in lots of different places (including on page 77 of my book). There are also lots of helpful links online. Here are a few:
Stress reduction: Deep breathing techniques
5 Anti-stress breathing techniques to help you feel calm anywhere
A breathing exercise to calm panic attacks
Do Something Productive:
Sometimes we can't do anything about a particular stressful situation we're facing – but wecan increase our own self-worth. Next time a stressful situation has you down, clean out your closet or reorganize kitchen shelves. The act of accomplishing something and seeing the results of your work can help to transform your mental state and remind you that you can accomplish anything (even if it's making your sock drawer more attractive).
Work It Out:
Besides making you even more beautiful on the outside and healthier on the inside, exercise releases endorphins that take your mental mood from sour to sublime. Even taking a brisk walk for just 30 minutes can make a difference. Try listening to "Feel Good" music that lifts your spirit while you're walking. And don't forget to pump your arms, pay attention to your posture and suck in that tummy for extra benefits from the walk (besides just strutting the stress away). For a few tips on effectively walking the stress away, click here.
Do you have personal stress busters that you rely on during times of mental turmoil? If so, I'd love for you to share them below with a comment. Or, if you dare, share an actual stress. I promise to help you 'Ommmm' your way through it!
You are how you eat
Much like me, haven't you always known, on some deeper level, that you really do embody everything you need — already inside of you — to achieve lasting physical health and a peaceful, happy state of mind (in relation to eating, your body weight and to everything else) you have always dreamed of?
And also like me, I imagine many of you know that nagging feeling that if you just had that one secret to unlock the door to your own innate healing powers, that you would finally shed the unwanted pounds, reclaim your health, and love yourself just as you are in this and all future moments?
I know from your emails and contact that a lot of you have been searching for the truth. And I also know many of you are tired of being told "Eat this not that." Well, the good news is that I am a part of a free online event that is going on now (and will conclude shortly) — so if you are ready to jump in and get access to being your best self without fads, shame or self-punishment, click here to take advantage of this Mindful Eating World Summit before it's too late to participate. (Again, it's free!)
Some of the tools and take-aways you'll get from this free online event include:
Stopping the "deprivation- and binge-eating guilt cycles."
Creating peace in your mind and your body to create an amazing
life with tools to empower you.
Cooking with "consciousness" and intention (the way nature intended it to be).
Making your mind your greatest asset to creating optimal health
and design a strategy that is unique to you.
Finding your path and live your purpose, because it's not
what you're eating, it's what's eating you.
My friend and colleague, the amazingly inspirational Dr. Kellee Rutley, has created an incredible resource where you can receive all of the tools you need to achieve optimal health, makeover your body and take your life back. Dr. Kellee and I can relate to what you are going through as can all of the experts that are contributing to this Mindful Eating World Summit. In fact, many of the experts on this summit have true-to-life stories they share regarding how they overcame every single obstacle you are facing right now.
Dr. Kellee has interviewed highly credible and respected Doctors, Naturopaths, Zen Masters, Holistic Psychologists, Holistic Chefs, well known Published Authors and true Fitness Experts with decades of experience — all sharing this "virtual podium" to provide you with the answers you have been looking for.
This Mindful Eating World Summit event ends on March 31st — so click here to get access to all experts before this summit is complete in the coming days. And there's no limit to how many can participate and benefit for from this Mindful Eating World Summit — so feel free to share this free sign-up link with friends.
Photo Source: FitDay

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87 Are Hurt as Subway Train Runs Into Another in Queens
By JAMES BARRON
Published: November 21, 1997
Rounding a curve in the waning minutes of the morning rush yesterday, a six-car subway train rear-ended another train that had paused at a red light in the tunnel between two stations in Queens, bumping and bruising 87 passengers and disrupting the underground lifeline for thousands of workers in three boroughs.
The 15-mile-an-hour crash also betrayed a flaw in the placement of signs on the platforms that tell train operators where to stop.
A Forest Hills-bound G train hit an eight-car R train coming from Manhattan that was filled with weary night-shift workers heading home and secretaries, nannies and hospital aides just beginning their day. Passengers who had been dozing, counting the stops or reading mystery novels were suddenly flung from their seats and thrown to the floor in a crash that some said sounded like trucks smashing into each other.
''We were just enjoying the ride, and boom,'' said Yomarys Valencia, who lives in Greenpoint, Brooklyn, and was on the way to her job at the Department of Environmental Protection in Queens.
The crash was the third major subway accident this year. On July 3, 13 passengers were injured when the last car of an A train jumped the track while moving through the 135th Street station. Investigators concluded that a track worker had flipped a track switch that the train was crossing. Less than two weeks later, four people were hurt in a similar mishap on a No. 2 train approaching the President Street station in Brooklyn. That accident was attributed to the failure of a relay device.
Transit officials who spent hours simulating yesterday's crash, just beyond the Steinway Street station in Long Island City, said the two trains were caught in a domino effect. The R train had been stopped at a red light because the train ahead of it was waiting in the 46th Street station, where a signal was malfunctioning.
As for the signals at the Steinway Street station, they appeared to have functioned properly, said James Dunn, an investigator from the National Transportation Safety Board. With the R train on the tracks between the two stations, officials said, the signal at the end of the Steinway Street platform should have been red.
But the train operator told investigators from the safety board that it was green. So did one witness, who works at a dry-cleaning shop in Richmond Hill, Queens, and just missed the doomed G train at Steinway Street. The man, Angel Vallejo, 29, said the crash felt like ''a miniature earthquake.''
For much of the day, investigators speculated that the train operator had crept by the signal using a procedure known as ''keying by.'' This overrides the emergency braking system and avoids tripping a spring-loaded arm in the trackbed that brings the train to a halt at speeds above 4 miles an hour. Train operators are supposed to ''key by'' a red signal only after receiving permission from a dispatcher or subway control tower.
Officials said the operator of the G train had not been given such clearance yesterday.
But in New York City's ancient subway system, there is nothing to prevent a motorman from sidestepping that regulation. ''There's no fail-safe system that says, 'O.K., you're going more than 5 miles an hour, we're going to shut you down,' like on other train systems,' '' said John Lockley, a line superintendent for New York City Transit, the agency that runs the subways.
After spending hours simulating the accident, officials said it had pointed up a flaw in the location of the signs directing motormen where to stop along the platform at many subway stations. Investigators said signs at some stations -- including the Steinway Street stop -- put the first car too close to the stop arm. When a train pulls out from that point, whether the operator is keying by or just accelerating to a normal speed, the arm cannot trip the brakes the way it is supposed to.
Officials said they solved the problem at the Steinway Street station by moving the marker where the train is supposed to stop a few feet back on the platform. They also began checking other stations throughout the city for the same problem last night.
Officials of New York City Transit would not identify the operator of the G train involved in the crash but said he had had no operating violations in four years on the job. A spokesman for the agency said that the only blemish in the operator's personnel file was for excessive absences. The train operator was tested for drugs and alcohol after the accident, but the results of the tests were not released.
An instructor of motormen, who spoke on condition of anonymity, said the G train operator was a good motorman.
''He was a conductor on my train when I was a motorman,'' the instructor said. ''He's a good guy, a good motorman.''
Officials said they did not know if the G motorman had applied the emergency brake before he struck the R.
The accident disrupted service on Manhattan-bound R and Brooklyn-bound G trains until about 1 P.M. Queens-bound trains on the R and G lines did not begin running until 4 P.M. The transit agency halted service on the E and F lines, which run near the Steinway Street station but do not stop there during the day, between 9:30 and 10:20 A.M.


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The Forum in Palermo has so many stores and restaurants ..really enjoyed.
you can reach there by bus or taxi
The Forum in Palermo has so many stores and also hairdressers, restaurants and an amazing food hall buzzing with celebration of anything Sicilian. The ice-cream stores have so many flavours and the portion sizes are so generous; just like the personalities of the Italian, sorry, Sicilian people. Can't wait to go again soon!
We visited Palermo independently (wheelchair and all) while on a cruise port stop. Started at Monreale, then came back to the Palazzo Normanni and the Cathedral. Walked just about the length of Corso Vittorio Emanuelle, saw the unusual statues at the Quantro Canti and the Pretoria Fountain. We wandered through the Vucciria market, which was mostly a flea market, ended...
went for shopping to Forum Palermo and really enjoyed,spend some hours,had a nice lunch there as well,taxi will bring you from Teatro Politeama just for 20 euros,will recommend..
After returning from our weekend break for my wifes birthday I just have to write this.
Most of the locals were not to friendly and if you was only wanting a coffee or a beer and a rest then it was worse, there was a couple of exceptions though. It was very expensive with a small coffee being anything from...
Wow--we LOVED this! Segways are so much fun! And Leo and our guide, Bianca, made this an all around amazing experience! From the carefully taught lessons to the interesting tour commentary, everything was perfect. I can't say enough wonderful things about our day! My kids (ages 15 and 13) both ended the day wanting segways for Christmas! :)
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Britney Spears' Unreleased Song 'Conscious' Leaks [Audio]
Britney Spears has been back in the studio working on her follow-up to 2013's 'Britney Jean.' But it looks like an unheard track has just made it onto the web.
Britney Spears has been back in the studio working on her follow-up to 2013's 'Britney Jean.' But it looks like an unheard track has just made it onto the web.
By now I'm sure you have seen the new music by Maroon 5 for their new single "Sugar"
If not the whole idea for the video is that Adam Levine wanted to travel around LA and "hit every wedding we possibly can," and become surprise guest performers.
The band has explained in interviews how the stunts played out. "Only the grooms knew in each case," they told Entertainment Tonight. "
In another interview, also with ET, Levine added, "It felt good to surprise these people and make them happy. happy that they liked our band too."
After watching the video below it seemed as if they pulled it off:
Several brides and grooms across LA got the surprise of a lifetime last month — when the band Maroon 5 crashed their wedding.
They performed the song, "Sugar," for the unsuspecting guests, and then made those performances part of their new music video for "Sugar
Yes, you read that headline right. Eddie Murphy has a new single out titled "Oh Jah Jah."
It is reggae inspired and, actually, isn't horrible, but it isn't amazing either.
Considering how eager all of us are to get new music from Rihanna, it should come as no surprise that even a possible leak of material is enough to get us excited. But is 'World Peace' actually a Rihanna song?
Sheerios, get ready to see an entirely different side of Ed Sheeran! The singer covered Foy Vance's 'Make It Rain' for one of the final episodes of 'Sons of Anarchy.'
For all of the Sam Smith lovers out there, you have to give this a listen.
Do you want to listen to all of Taylor Swift's "1989" album really fast?
During her Art Basel performance on Dec. 3, Miley Cyrus introduced 'The Twinkle Song,' a new track with a very unexpected origin.
If you've never seen the Trans-Siberian Orchestra perform, don't even bother imagining what might unfold.
It is something seemingly beyond the realm of reality that is being brought to Grand Rapids for Trans-Siberian Orchestra's performances at 3 p.m. and 7:30 p.m. in Van Andel Arena.
After DJ Skee totally failed to deliver that Rihanna news promised to us yesterday (Nov. 25), the Bajan beauty herself took to Instagram to unleash a new song snippet instead.
Ariana Grande has come out with her own Christmas Song and it is not your typical song.