Wednesday, September 28, 2016

How Do Chemists Discover New Drugs? A Brief Introduction!

How do chemists discover new drugs?  Obviously, in the laboratory!  Is that all one can say about the process?  Certainly not.  There is a process by which discovery happens.  The process may vary depending on which laboratory a chemist works in.  Although, the process does not vary so greatly as to eliminate a general procedure or process a drug takes from laboratory to the marketplace.  In the blog below, I introduce the general process by which drug discovery proceeds.  I want to highlight the word "introduction" since depending on your level of understanding, the process can be described in different ways.

Drug Discovery - General Route

I recently stumbled upon a video made by the 'National Institutes of Allergy and Infectious Diseases' (NIAID) titled "How A Drug Becomes A Drug" which I will show below in a moment.  Before I emphasize the importance of viewing the short video (less than 4 minutes), I want to introduce the agency NIAID -- which is a sub-agency of the 'National Institutes of Health'.  Here is an excerpt describing the organization taken from the "Wikipedia" page for the "NIAID" below:

The National Institute of Allergy and Infectious Diseases (NIAID) is one of the 27 institutes and centers that make up the National Institutes of Health (NIH), an agency of the United States Department of Health and Human Services (HHS). NIAID's mission is to conduct basic and applied research to better understand, treat, and prevent infectious, immunologic, and allergic diseases.[1]
NIAID has "intramural" (in-house) laboratories in Maryland and Montana, and funds research conducted by scientists at institutions in the United States and throughout the world. NIAID also works closely with partners in academia, industry, government, and non-governmental organizations in multifaceted and multidisciplinary efforts to address emerging health challenges such as the pandemic H1N1/09 virus.

The three main mission areas can be summarized from the "Wikipedia" page as follows:

Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS)
The goals in this area are finding a cure for HIV-infected individuals; developing preventive strategies, including vaccines and treatment as prevention; developing therapeutic strategies for preventing and treating co-infections such as TB and hepatitis C in HIV-infected individuals; and addressing the long-term consequences of HIV treatment.
Biodefense and Emerging Infectious Diseases (BioD)
The goals of this mission area are to better understand how these deliberately emerging (i.e., intentionally caused) and naturally emerging infectious agents cause disease and how the immune system responds to them.
Infectious and Immunologic Diseases (IID)
The goal of this mission area is to understand how aberrant responses of the immune system play a critical role in the development of immune-related disorders such as asthma, allergies, autoimmune diseases, and transplant rejection. This research helps improve the understanding of how the immune system functions when it is healthy or unhealthy and provides the basis for development of new diagnostic tools and interventions for immune-related diseases.

The above mission covers every disease known and unknown.  The National Institutes of Health is a huge organization made up of sub-agencies like the NIAID to divide up the mission.  As such, the NIAID oversees the funding of drug research to a large extent in order to understand how infectious disease compromise the immune system -- the body at large.  Additionally, the NIAID is interested in how drug discovery overcomes infectious diseases that have invaded our body.  This includes the research behind the disease at the academic level.

I mentioned above a short video to highlight the general process of drug discovery from the academic level up all the way through to the consumer level -- i.e. the pharmacy.  Here is the video below -- which is worth watching:

In the video above, the research is said to start at the basic science level at the university.  This is true to an extent.  Basic research into disease function and origin typically starts at the university level.  Although, I would add that a fair amount of research is done at the industry level too by large drug companies.  That research is typically targeted at a specific disease in which the pathway of progression or origin is known.  I will explain more about the last sentence shortly.

The drug companies take the research done at the academic (university) level and carry the "small molecule" or "drug target" out to an actual therapeutic that is sold on the shelf of the pharmacy.

Why is this important to know?

Periodically, in the popular news, stories emerge about the over pricing of medication by companies like Turing pharmaceuticals (outrageous pricing) which cause wonder as to why such high prices exist for a given medication.  These instances (of over pricing) are minimal compared to the price point needed to make a profit and move onto research more efficient drugs.  The point is that research at the companies take time and money along with infrastructure.

The overall benefit of such research could be realized through an "open-access" network of drug targets and therapeutics (proprietary information at the moment) to which other researchers could access at their leisure.  Arguments for such a system is that the funding has been provided by a government agency.  Whereas arguments against such a system is loss of proprietary information.  Tough call.  Sorry for the divergence.

The goal of research is to find effective therapeutics (drugs) that treat a large part of the population.  Side effects come about as a result of non-target delivery.  The drug misses the target of intent or hits additional targets and causes extra problems.  This is where the concept of "personalized medicine" comes in and will be discussed in future blog posts.  For now, lets focus on designing drugs for a certain disease.

Drug Design 101

In order to design a drug to treat a certain disease or ailment, the pathology of the disease needs to be known.  The origin of the disease needs to be known.  How did the disease originate in the body?

Is the disease the result of a mutation in the genetic make-up of the person?

Is there a mutation in the DNA of the patient which causes a downstream mutation in the production of proteins?

Is the protein distorted in shape, contour which affects function?  

Is the disease caused by an external agent (i.e. virus or bacteria)?

These problems can plague researchers success greatly for years.  Luckily, over time, drug companies have built up libraries of "molecules" that serve as "messengers" or "therapeutics" that can hit a specific target that is involved in the process of the disease.  Here is an excerpt from the "Wikipedia" page for "drug design" which I think will help you understand the process at the research level in either the university or industry setting:

Drug design, often referred to as rational drug design or simply rational design, is the inventive process of finding new medications based on the knowledge of a biological target.[1] The drug is most commonly an organic small molecule that activates or inhibits the function of a biomolecule such as a protein, which in turn results in a therapeutic benefit to the patient. In the most basic sense, drug design involves the design of molecules that are complementary in shape and charge to the biomolecular target with which they interact and therefore will bind to it. Drug design frequently but not necessarily relies on computer modeling techniques.[2] This type of modeling is sometimes referred to as computer-aided drug design. Finally, drug design that relies on the knowledge of the three-dimensional structure of the biomolecular target is known as structure-based drug design.[2] In addition to small molecules, biopharmaceuticals and especially therapeutic antibodies are an increasingly important class of drugs and computational methods for improving the affinity, selectivity, and stability of these protein-based therapeutics have also been developed.[3]
The phrase "drug design" is to some extent a misnomer. A more accurate term is ligand design (i.e., design of a molecule that will bind tightly to its target).[4] Although design techniques for prediction of binding affinity are reasonably successful, there are many other properties, such as bioavailability, metabolic half-life, side effects, etc., that first must be optimized before a ligand can become a safe and efficacious drug. These other characteristics are often difficult to predict with rational design techniques. Nevertheless, due to high attrition rates, especially during clinical phases of drug development, more attention is being focused early in the drug design process on selecting candidate drugs whose physicochemical properties are predicted to result in fewer complications during development and hence more likely to lead to an approved, marketed drug.[5] Furthermore, in vitro experiments complemented with computation methods are increasingly used in early drug discovery to select compounds with more favorable ADME (absorption, distribution, metabolism, and excretion) and toxicological profiles.[6]

The drug designer is looking for a "biological target" that is involved in either the origin or progression of the disease.  As mentioned above, there are two popular processes: computer-aided drug based design and structure-based drug design.  Both involve information on the biological target of interest.

What might a biological target look like?

A biological target can vary in definition depending on the nature of the disease.  For instance, if the disease involves the distortion or mutation of a protein, then the surface of the protein would be considered the biological target.  Specifically, the site of interest for a drug to interact with is referred to as the "active site."  Here is an image take from the "Wikipedia" page for "Active Site" to help assist the reader in what that might look like:

Source: Thomas Shafee - Own work, CC 

As you can see, the protein appears to be like a "blob" in the image above.  The reason for that to emphasize the "binding site" or "catalytic site" not the overall structure which is of little concern to the drug designer.  Remember that proteins are made up of amino acids which in turn form large "macromolecules" some of which are referred to as Proteins.  I wrote an earlier blog about oligosaacharides are made up of simple sugars.

Starting from the picture above, now, the video below might make sense to watch before we proceed with our discussion of drug design.  The video is titled "A Basic Introduction to Drugs, Drug Targets, and Molecular Interactions" and is just over 4 minutes long -- and definitely worth watching.

The video above is more technical than some readers might want to view in order to understand the process.  Therefore, we should back off a little on the "technical side" and focus on the "development" side of drug development -- from a simplistic standpoint.

Are you ready to understand drug design from a simple standpoint?

Alright, here we go!

In order to do so, I decided to borrow a few slides from a recent webinar offered online by the American Chemistry Society.  The webinar was titled "Crystallography As A Drug Design And Delivery Tool" and was given by Dr. Vincent Stoll of AbbVie -- where he serves as the Director of Structural Biology.

One of the examples that Dr. Stoll used to talk about drug design was binding to the transmembrane molecule B-Cell-Lymphoma-Extra-Large or bcl-xl in the mitochondria.  In his talk, he focused on a few binding sites shown in the slide below with a picture:

Specifically, in this case the company wanted to design a drug candidate that would "mimic" the peptide Bak binding.  Shown to the right on the slide are the sites or "active sites" that the peptide Bak bind to on the transmembrane molecule bcl-xl.  In order to find a drug that will mimic the binding of the peptide, the drug will have to have the ability to bind to multiple sites on the transmembrane molecule.

Fortunately, over time, large drug companies have built up a data base or library of 'molecules' that will bind to similar or exact sites.  In the slide below, I show a yellow surface with two molecules hovering above the surface -- slightly bound -- taken from Dr. Stoll's talk:

There is a lot of information on the slide shown above.  Let me walk you through the relevant information for drug design 101.  First, I mentioned that each drug company kept a library or database with a bunch of 'fragments' that are intended to hit specific targets on biological surfaces.  These biological surfaces can be viewed as the picture shown to the right in the slide.  They might be a protein surface, or another biological surface of interest to drug manufacturers.

In the case above, the two molecules shown on the yellow surface -- one is a brown color while the other is a green color.  The different color is to illustrate that the molecules are fragments designed to hit a specific type of target or active site on a biological surface.  In this case, the biological surface is the transmembrane molecule bcl-xl.


Once the fragments have been identified that will occupy and hit the desired targets or active sites, then the challenge is to link the fragments together by chemistry.  This step in of itself is often challenging and does not guarantee that the newly formed molecule (of two fragments with a linker molecule) will work.  Therefore, in the picture above, there are possible linker molecules that exist within the pharmaceutical database that have been shown to work in other cases.

After linking the two fragments together, the next step is to verify by spectroscopy that the total or linked molecule worked.

How is this accomplished?

In the lab, the substrate or biological surface will have a drop of the linked molecule injected onto the surface.  Then the surface which should have the drug bound to the active sites will be investigated using a spectroscopic technique like Nuclear Magnetic Resonance Spectroscopy.  Upon confirmation, a number will be reported as shown on the slide that indicates the binding affinity of the molecule onto the surface:

In the slide above, there are a couple of numbers reported that make sense to drug designers but probably not the reader -- you.  Do not worry.  Over time (through other blog posts) you will come to understand their meaning.  What is important to understand at this point is that after linking molecular fragments together, an experiment occurs to understand if the drug or linked molecule is as effective as the fragments are alone.

Furthermore, the pharmaceutical company might understand the chemistry of the active site to a large extent and further modify the linked molecules to make a more "potent" drug or linked molecule.  On the slide below, I show from Dr. Stoll's talk such a modification:

Again, the overall take home message is that the molecular modification done to the linked molecule has some effect.

Is that effect better or worse?

Can there be a further modification to the linked molecule or now drug to enhance the ability to mimic the peptide binding?

Who knows.  That is why research is continuously pushed forward and costs money to find out.


In the above paragraphs, my intention was to introduce briefly the process of drug design.  As we speak though, changes are being made to parts of the process.  Outsourcing of linker molecules is occurring as are mergers and acquisitions of large companies by even larger pharmaceutical companies.  Which potentially means that the shared database or libraries of available drug targets is growing.  The process is dynamic but slow at the same time.

Discovering the mechanisms of disease and cures as a result is the dream of every drug designer.  Progress is unfortunately slowed down by the trial and error process.  Research takes time and money to complete.  Furthermore, improvements to existing drugs take time.  I will leave you with another short video about the progression of the medical research field:

Until next time, have a great day!!!!

Friday, September 23, 2016

An Alternative Way To Tour A City — By Your Nose!

Note: This article was written last year!

Just last night, I came home from work and I was making dinner using the microwave. I was preparing a ‘microwavable meal’ of pasta–sounds great right–the meal did the job to say the least (which needs no further comment). While I was stirring the meal in between cooking cycles in the microwave, I started to smell an unfamiliar smell which I could not place in my kitchen. Although, when you are hungry–the stomach tends to ‘out rank’ all senses in ‘reason’ or ‘logic.’ I noticed that the door was open and went outside to see if by any chance the smell was coming in through the door...

Before I finish the story that I started let me cut to the chase.  I was reminded of an article that I read concerning our (humans) relationship with smell and design layout in a large city. What was suggested as a ‘smell walk’ in the article, I was actually mimicking in my own home without realizing this behavior. We do this all the time without really placing emphasis on this talent. This method could be extended to touring the city according to the news. Let me explain in the post below.

What Is A ‘Smell Walk’?

Until I read an article in the ‘New York Times ’ recently, I was unaware that a ‘smell walk’ existed. I would reserve such a description to the tour of a factory (industry) – food, perfume, chemical –exclusively not to the topic of touring a city, much less observing the history behind a city based largely on the sense of smell. The article was titled ‘Don’t Turn Up Your Nose At The City In Summer".  Dr. Victoria Henshaw describes our relationship with odor as follows:

We tend to think of a heightened sense of smell as an animal skill — something our pets are better at than we are — but our olfactory systems, too, are clever at filtering and categorizing the smells we detect. We sort odors into the familiar, which represent no threat, like the scent of our own homes, while the unfamiliar are brought to our conscious attention, whether as potentially pleasurable or possibly insalubrious. 
The downside of this filtering process is that we fail to appreciate the sheer volume of smell information we process on a daily basis. Those who lose their sense of smell attest to the scents they desperately miss, as well as to the fear that comes with being unable to detect smoke, gas or rotten food.

My fascination with smell as stated earlier was limited in scope up to a few months ago. In a previous blog post, I highlighted the research conducted that determined that humans can differentiate between around 1 trillion different scents. Of course, the larger degree of overlap in scents increases the difficulty in differentiation on the part of the test subject (human). To observe a city through the sense of smell was surprising and foreign to me. Usually, olfactory information is suppressed or less prioritized in the grand scheme of day to day interactions with the environment. According to Dr. Henshaw this sensory information contributes more to the design of a city than inhabitants (residents) know which is highlighted in the article from ‘The Times’ here:

In New York, smell was a key factor in the city’s original planning. Devising the grid system in the early 19th century, the city commissioners aimed to maximize the benefits of westerly winds to dissipate the supposedly deadly miasmas thought to spread disease. Odor standards were enforced by local smelling committees. In 1891, in the 15th ward (Greenwich Village), members identified pollution from an oil refinery by following their noses. 
The surprising thing is that they could detect anything over the smell of human waste. In 1890, The New York Times reported that the city’s sewers dumped an estimated 100,000 tons of fecal matter a year into the harbor. Industry added to the problem: An inspection in 1910 found that in Yorkville, home to German immigrants at the time, brewery effluent flowed in the pipes, while around Canal Street, the smell of banana oil — used as a solvent by painters — dominated. 
Odors can often provide a guide to the city’s industrial past, even decades after smoke has stopped pouring from the stacks. In London’s Olympic Village, for example, the main stadium was built on a former industrial zone — and when it rains, locals report detecting the smell of soap seeping from the site of an old factory. 
Smell also provides a sociological map of the city. Poorer people tend to have less control over their smell environments. Residents of Hunts Point, in the Bronx, suffered for decades from the acrid odors of the waste-treatment plants there. Only after a public and private nuisance suit was brought by residents and activists in 2007 did the city settle the case and clean up its act.

Of course, I admit that I am not a city planner, instead a chemist. In the course of a chemistry education, the average student (and graduate student) is exposed to a wide range of volatile chemicals and as a result becomes accustomed to differentiating his/her way through the vast ‘smellscape’ of the chemistry research laboratory. Although, when the same student steps out onto the street, a disconnect is present to the urban environmental smells surrounding them. This is an area of science communication in which there is tremendous room for improvement. Courses such as ‘the science of cooking’ have been concocted to combat this disconnect between the laboratory and the outside world (a much larger laboratory). There exists a vast array of smells (some concocted and some uninteded) that invade our noses on a daily basis that we are unaware of and do not appreciate as a result of other dominant senses. After reading this I decided to look further into Dr. Henshaw’s research of our relationship with smell and city planning. Dr. Henshaw is a Professor of Urban Design and Planning at the University of Sheffield and has studied the role of our relationship with the sense of smell in a variety of environments. Work like that of Dr. Henshaw provides us with a new vernacular from which to view problems associated with the environment and sustainability. She has a blog on which there is a large number of articles highlighting her adventures with smells.  In addition, she has written a book that should be in print soon. On her blog post describing her book, she expands further on her interest with smell and urban planning as highlighted here in this excerpt:

In Urban Smellscapes I draw from detailed research with participants in Doncaster, Manchester, Sheffield and London (UK) and the wide range of smellwalks I have conducted around the world including those in Edinburgh (UK), Seattle and New York (US), Grasse (France), Montreal (Canada) and Barcelona (Spain). I explore relationships between our individual senses of smell and personal characteristics, alongside factors relating to the world surrounding us such as the buildings and streets we walk through, the activities that take place within them and the people and objects we encounter. By drawing from people’s descriptions and perceptions of the smells they encounter, I identify a range of different tools and models for deconstructing and designing smell environments, and in doing so I hope that city leaders, architects and urban designers are better equipped to take a more positive approach to smell when designing places and spaces in the city.

I love to learn about new ideas and research. Since I read about this research last week, I have been thinking about various ways in which I have ignored the smells surrounding me on a daily basis. Throughout the day, I tend to ignore smells, but as the research above indicates tourists and city dwellers are missing out on an untapped dimension of pleasure continuously. Without even realizing it, when we step into our homes each night–each of us perform experiments with our noses that send a signal to our brain that the building (our home) is indeed matched with our sight (our visual observation). This simple task may seem mundane since each of us perform an experiment continuously unconsciously. Think about how often you carry out an experiment with your nose to validate your visual experimental observation–very frequently. The combination of smells and sight provide us with comfort, whether it is at home, work, a favorite restaurant, a family physician, etc.. This leads me back to the story of cooking my pasta at the beginning of the blog post. Let me explain below.

An Unfamiliar Smell In A Familiar Place

Navigating the ‘smellscape’ in our home is task that is continuously done. As I started the post, I was cooking a meal in the microwave and smelled an unfamiliar smell that I had never experienced while cooking this particular meal before. My mind started to wander all over the place. I started asking myself – did I burn something? Is that the smell of burned plastic? Is there something else burning that was left over in the microwave? I was smelling while hungry–or anticipating my meal. After the meal was cooling, I was ready to eat and I looked over at the ‘trash can’ only to find that there was a used up bag of ‘microwaveable popcorn’. In the midst of being hungry, I could not even determine the correct origin of the unfamiliar smell. In addition, I was recalling a history of cooking events that had taken place in our kitchen over the last 24 hours only to realize that my wife had cooked some popcorn earlier that day. I did not connect the fact that she had been on vacation (off from work) and stayed home and produced an unfamiliar (or unknown to me). I was amazed at the events that unfolded in this scenario.

Here I was worried about a smell that I linked to the current meal that I was making–which is normal. I was not enjoying the variety of smells that were in our kitchen as a result of meals that had been made. The history of odor was dominated by my immediate task which was to make dinner. This observation ties into the above discussion of smell walks–in that–I was only concerned about the smell in relation to the present. I was not appreciating the variety of history that was contained in our ‘trash can’ since the last disposal. I realize that I have rambled on a bit. This blog is rather loosely tied together. The point is that we are inundated with a variety of odors on a daily basis and choose not to filter them out for the pleasure of observation–unless there is an immediate need to differentiate between them. Restaurants along with retail stores make use of our odor differentiation to sell us products everyday consciously and unconsciously.

Marketing and advertising consultants use the sense of smell to guide the consumer into a store (or try to). Historically, the use of chemicals (fragrances, odor trapping, odor masking, etc.) in products and advertising is a well-developed area of marketing. Although–with the technological development of ‘diffusers’ along with other distribution devices coupled with chemical synthetic methods, chemistry has helped the economy through sense of smell in a variety of ways. I was not surprised to read that certain stores spray odors (synthetic chemicals) that match the products that are sold inside. As technology is developed further into odor identification and synthesis, expect more exciting and undeniable hidden influences to draw you into a given establishment. The use of odor to attract customers was embedded in the design layout of a store or restaurant in past time. Now, with the precision of chemical synthesis to make remarkable odors that are very familiar as well as enticing to our olfactory sense, our ability to withhold the temptation to a given food or fragrance product is decreasing. Retailers are enlisting the help of psychologists, sociologists, and other scientists to hone in on a product that will sell with little resistance (on the customer's part). These tactics used by marketers and advertisers should not be cast in a negative light. Instead, the consumer should appreciate the diversity and precision that science lends in producing products that are appealing to the nose of consumers and invoke a desire to purchase or eat. There is a lot of science involved in the product development. As a consumer, I am always fascinated by the creative effort that is behind such products.

The new lesson learned from reading and exploring Dr. Henshaw’s research is that I will from now on try to focus more attention to my nose than I did previously in the past. By the way, if you would like to learn 5 tips to having a better ‘smell walk’ from the expert herself, check out Dr. Henshaw’s blog post outlining suggestions. I challenge the reader to do the same. Think about all of the neglected smells that you encounter on a daily basis. Further, challenge yourself to view the layout of a big city (such as New York City, Los Angeles, Chicago, etc.) in terms of the smell distribution. Compare the layout of the city with the history. Does the smell match the past? What differences have you observed? Summer time is a time to get out an enjoy the beautiful weather outside. In addition, with this new information learned, an added component awaits your adventure. Enjoy the wide range of sensory information provided by a city’s odors alongside the traditional ‘sight seeing’ in your adventures.

Monday, September 19, 2016

Why Is There Another Oil Spill?

This is the question that I ask myself after viewing the following picture on twitter below:

Usually, the next question is the following:

How many gallons spilled this time?

Sounds like I am beating the same old drum.  I am.  A correction first in my initial question.  According to the news, gasoline spilled, not raw oil from the ground.  Other news sources quote oil.  Regardless, large volumes of any chemical that spills in any geographical area is not great for the environment.  Why? First, the following question:

Why can't these large oil companies get their act together and put infrastructure in place to stop such large volumes from polluting the environment?

In order to agree or disagree with me, we should explore the amount of oil that actually spilled in the cited case in Alabama.  First, I want to highlight that based on previous blog posts on my site under the theme "Large Volume Spill" -- the reported amount can be put immediately into perspective.  That is to say, if you have been reading the past blog posts, then upon reading the reported number of barrels of oil spilled, the volume should make sense.

To an extent, that realization is rather disappointing since that means this is not an isolated case.  Before we draw out more emotions, lets look at the numbers reported and subject the values to dimensional analysis.  Below is the result.  Enjoy!

How Many Gallons In A Barrel?

In order to understand the magnitude of the spill in Alabama, there are two values that need to be known.  First, the volume of oil that actually spilled -- usually reported in units of 'barrels'.  Next, the conversion factor from 'barrels' to 'gallons'.

According to the news site "NBC News," the amount of oil that was spilled was in the range of 6,000 to 8,000 barrels.  Here is an excerpt about the spill taken from the article:

It's unclear when the line started leaking, but Colonial said in a statement that the leak was detected on Sept. 9, and about 6,000 to 8,000 barrels of gasoline had been lost.

The company said there are no threats to public safety because the leak has been contained, but warned that parts of Georgia, Alabama, Tennessee, North Carolina and South Carolina gas markets would first be affected by the "disruption in supply."

Patrick DeHaan, a senior petroleum analyst with, said prices at the pumps in those states could swell by 5 to 20 cents a gallon. "And it could be even worse," he said.

Where did the gasoline go?  According to the reports, the gasoline has 'pooled' into a 'retention pool' nearby preventing the gasoline from leaking into either the ground water or the nearby river.

Why is this so sketchy?

Why do we run a pipeline next to an important river?

Time and again, we see these designs in the interest of improving the bottom line of the petroleum companies on top of keeping Americans depend on cars.  Over the last two years, there have been enough examples of the failure of retention pools.  Think of the Gold King Mine waste spill in Colorado.  How about the Brazil mine wastewater spill?  And just a couple of days ago, there was a spill in Florida -- which I will write about in the next week or so.  In times such as these, one has to wonder why the companies want to risk damage to the environment too?

Lets put that discussion on pause for a minute in order to understand the magnitude of the spill here.

How many gallons does this volume equate to?

The conversion factor from a 'barrel' of oil to a 'gallon' of oil is the following provided by the website "":

There are 42 gallons in one barrel.  If you perform the following calculation take 1 and divide the number (decimal number above) as follows: 1/ 0.0238 to get 42 gallons.  With these two values, the range can be calculated as shown below:

Wow!  Earlier, I suggested that based on the previous posts on this blog, the numbers should be easily put into perspective.

What did I mean by the statement?

How Does The Spill Compare To Refugio?

A couple of years ago, the California coast was once again rocked by an oil spill.  Again, in Santa Barbara.  The name of the spill was Refugio after the beach on which the oil washed up.  I wrote a blog post about the spill that has tainted the beaches below the northern beach.  We still see the effects to the environment -- which are not pretty and devastating.  Unfortunately, we accept them as part of our dependence on oil.

How does the current gasoline spill compare to the oil spill at Refugio Beach?

The Refugio oil spill was small (142,000 gallons) compared with the enormous 'Deepwater Horizon' Oil spill caused by the BP Oil drilling off shore (210,000,000 gallons).  Of course, the 'off shore' drilling was further out.  The spill near the beach in California was three orders of magnitude less than 'Deepwater Horizon'.  Still, a man-made disaster should not have happened in the first place.

If the value of the current gas spill in Alabama is divided by the volume of the spill in Refugio Beach, the answer is the proportion of one spill to the other as shown below:

Which is to say, the results above based on the ranges calculated for the gasoline spill in Alabama suggest that the spill was 1.7-2.3 times the oil spill in Refugio Beach.  The spill overall was small compared to the previous spill entertained on this blog site.  Although, any damage to the marine environment or the public drinking water system is too much damage.

What else can be said about the volume of gasoline spilled in Alabama?

Again, if you are a consistent reader of the site, then you can look at the volume and say the following:

The amount that was spilled was relatively small in comparison to recent large volume disasters.  If we take an Olympic Swimming pool to use as a metric, not even half of the pool would be filled.  Really?  Yes, the volume of an Olympic Swimming pool is around 660,000 gallons.

You might be wondering where I got the idea to include the Olympic Size swimming pool.  In the "introductory post" for this site, I include an Olympic Size swimming pool as a metric in a dimensional analysis calculation.

Should we be worried about the spill?

Conclusion ...

Based on the last few statements, one might not be concerned about the spill due to the 'relatively small volume' of the spill.  Then I would ask the following:

If that volume were small, then why is the price of gas starting to rise as a result?

The answer is due to two culprits.  First, the amount that spilled is contained and not a huge amount -- therefore, we have lost some gas.  The second culprit is the significant parameter in the loss of gasoline.  The infrastructure is a large part of the supply chain and will need to be repaired.  Here is a diagram of the pipeline that busted and leaked gasoline taken from the video in the article mentioned above:

According to the map above, the pipeline delivers 40% of the gas to the region.  

Why do companies build pipelines like this?  

In the event of a break or leak, the entire system is shut down.  I have yet to understand the reasoning behind such construction.  

Maybe a reader can provide us with some information?  

Anyone out there work for a petroleum company want to educate the audience?

Regardless, in the Midwest, there is a current dispute with a native nation about the pipeline crossing property.  Additionally, the proposed pipeline will cross right on top of an aquifer in Nebraska.  Is this a good idea based on the current events unfolding in the nation -- with regard to large volume chemical spills?  Why don't politicians connect the dots between the two disasters?  I hate to speculate, therefore, I will end the post here.

After reading the above post, the spill should be easier to understand.  Furthermore, in the future, a spill will be easier to cast into perspective given the methodology explained in the brief post with the dimensional analysis.  Until next time, have a great day!

Thursday, September 15, 2016

Humor Series #1: We Live In A World Where ...

Normally, the subjects that are entertained on my blog site are centered around looking at statistics that are reported in the popular news or in various journals.  To "mix it up a bit," I thought that every once in a while when I hear a VERY Humorous story, I could pass the story on.  I will call the series "We Live In A World Where ...".  Added to the humor will be shocking stories about events that should gain entry into the Darwin Awards.   The second story (second post) will be one such story.  First, lets hear about a student and their ride sharing experience while getting to class.

I Need A Ride To School!

The other night my wife came home and told me a hilarious story about her day.  She is a professor and teaches general chemistry at a college.  As such she gets to interact with a large amount of students each day -- more students than I do.  Therefore, the probability that her story will be hilarious is much higher than mine.

Ride sharing services are becoming ubiquitous in our society.  At least here in the United States.  Here is a story that a student gave as an excuse as to why she was late to class the other day.  The story is in dialogue form.  Dr. Kaiser is Kayla Kaiser -- my wife.  Zoe -- will be the fictitious name of the student -- to ensure privacy.  Enjoy.

Backstory to dialogue.  On the first day of the semester, Professor Kayla Kaiser announces the rule for the remainder of the semester -- regarding tardiness -- or being late to class.  She states that there are two doors to enter into the classroom.  If a student is going to be late, to please use the rear door.  This is to not disturb the class that is in session.  Of course, students will be students and walk right in front of her while she is standing at the front lecturing.  This commands the following dialogue:

Dr. Kaiser: Hello, who are you and why were you late ... tell us?

Zoe: Parking ...

Dr. Kaiser: Oh yeah, where did you park?

Zoe: Professor, I parked so far away, I had to "Uber" it in.

Story Review:

First, to clarify a statement regarding "Uber".  For those who are unfamiliar with the ride hailing services (private taxi cab), people use "Uber" or "Lyft" instead of a taxi cab.  The ride services is provided by people who use their private cars as taxi's.

Here is the review of the story.  We live in a world where ... a student would either: 1) use a ride hailing service as an excuse for being late, or 2) actually, not have the ability to park a (small distance) off-campus and walk in.

I was amazed at the student.  I was trying to imagine where could I park around campus that is not within walking distance and warrant using the "Uber service".   I ride my bike to the train station every day and then unboard at the station which is just over a mile from campus.  Even if I did not have a bicycle, I would still walk from the train station.


This student has lost her mind.  Until next time, have a great evening.

Monday, September 12, 2016

Why Is Elon Musk Powering A Freight Ship With A Rocket Engine?

Alright, Elon Musk might not be planning to power a freight ship any time soon with a rocket engine, but he is moving extremely fast with his "overly ambitious" space program.  Do you believe me?  Fortunately, my word does not have to be taken.  According to a news article that appeared in the Los Angeles Times recently titled " Is Elon Musk trying to do too much too fast?" an analyst is quoted with the following view of Elon Musk's progress:

“This raises serious questions about the reliability of the SpaceX launch vehicle,” said Loren Thompson, a defense analyst at the Lexington Institute, which receives money from Boeing Co., a SpaceX competitor.  “They are taking this technology to the limits.” 

Boeing is not a competitor since Lockheed Martin and Boeing formed a relationship called the United Alliance Launch -- that funds SpaceX's adventures.  Additionally, the analyst is speaking in terms of experience.  Regardless of opinion, the pace at which Elon Musk is pushing and promising payloads into space is calling into question the reality of delivering such low cost and reliable delivery.  In order to understand arguments either way, a closer look at the space ship might help us understand the challenges.  As a metric for comparison of the thrust required to project objects into space, a freight ship might suffice.

The post below was written in relation to the terrible accident that occurred on September 1, 2016 in Florida at the Space Station.  Here is a video of the unfortunate explosion that occurred before launch while filling the fuel tanks on the rocket:

In order to understand the magnitude of the disaster shown above, dimensional analysis needs to be carried out.  First, a short discussion of the commercialization of space might serve the reader well as a starting point.

Space Exploration Takes Time, Patience, And Funding!

Space exploration by various countries around the world has been around for decades.  Research and discovery in the area takes a considerable amount of time and funding.  Why?  There exists many reasons that are questionable.  What is not questionable is the fact that NASA has considerable experience and extensive analysis of what works and what does not work.

Furthermore, there has been a decline in funding for NASA projects over the last few decades which is truly disappointing.

What is the thought process behind the decline in funding?

Again, the answers are numerous and questionable.  Another unquestionable certainty is the deliverable technology that is "spun off" from such research and design that hits the market in the form of everyday products ranging from foam pillows (space pillows) to special lubricants (that have a dynamic range of parameters).  Undoubtedly, our lives are better as a result of the R&D that NASA has completed over the last few decades.  There is no question there.

Why commercialize space?

Another fascinating yet open-ended question.  Since the decline in funding, maybe the large aerospace corporations are looking to increase their profit margins back to the point during the hey-day of aerospace R&D.  Regardless, the promises and results that are arising today as a result of the new direction of space flight are making investors and the public uneasy.

Just this week, the space arm of Virgin Airlines -- Virgin Galactic promised to resume R&D testing to send high-paying customers into the upper atmosphere - lower space orbit.  Here is an excerpt from an article in the Los Angeles Times this week:

SpaceShipTwo eventually will be in the business of carrying tourists who have paid up to $250,000 into space. The sleek spaceship will be released at about 50,000 feet by its carrier aircraft, then propelled by rocket to more than 50 miles above the Earth — past the point where NASA and the U.S. Air Force consider a passenger to be an astronaut.

Last summer, the National Transportation Safety Board said the first SpaceShipTwo broke apart because the copilot had opened the aircraft's movable tail, or “feather system,” too early. The system is intended to help the craft slow down after its descent from the Earth's atmosphere.

The NTSB placed most of the blame on the plane's builder, Mojave-based Scaled Composites, which is owned by Northrop Grumman Corp. The agency said the plane's design should have protected against the possibility of this human error.

These types of results are exciting from a possible consumer standpoint.  Although, the loss of life is unacceptable.  Especially, since space and aircraft travel have been optimized over the course of many decades.  What is the difference?  Today's exploration is being pushed beyond limits -- too fast -- I would argue.

New materials and research results are rolling off of the academic press without proper testing before being incorporated into new technology.  This has always been the case with the toxicity of chemicals in consumer products.  The government is finally starting to take a closer look into the matter with the newly update Toxic Substance Control Act (TSCA) reform (different subject -- same concerns).  Dr. Richard Denison of the the Environment Defense Fund writes extensively about the subject -- here.

How do we understand the magnitudes of such discoveries?

Returning to the commercialization of moving cargo into space, can we visualize the feat that is to be overcome in order to obtain success?

As I mentioned above, NASA has devoted a significant amount of time in Research & Design over the last few decades.  I decided to show a few videos of the advancement in testing and construction of critical components that make-up a rocket engine boosting a payload (cargo) into space.  Specifically, I focus on two major components: Fuel tank and Rocket engine booster.

Fuel Tank Construction:

Imagine trying to launch a payload of several tons up into space.  What does such a feat require?  First, the design of the rocket should be sufficient to meet the criteria of getting the cargo into space.  At the very least, the fuel tanks should be sufficient to hold enough fuel to lift the payload into space.

As you will recall in a previous blog post on the gases helium and hydrogen, in order to arrive in space, the molecules of either gas must overcome the gravitational pull of Earth's gravitational field.  The escape speed (escape velocity) was determined to be around 7 miles per second.  Wow!

How much fuel would be required to lift a giant space rocket?

Below is a video of the SpaceX falcon 9 fuel tanks being processed -- taken from the spaceX youtube channel:

Here is a time-lapse video of the construction of such massive tanks from NASA at the Marshall Space Center:

An enormous amount of consideration must be devoted to the design of the fuel tanks.  Especially, when considering the temperature of the liquid fuel (cryogenic temperatures) being consumed.  Remember, the liquid hydrogen needs to be stored at cryogenic temperatures -- at around - 423 F or - 252 C.  That is freezing.  Special care must be taken to avoid any explosion or sudden loss of fuel.  From the time the space craft is filled, the fuel is evaporating.  With the temperatures this cold, it is amazing that the controlled explosion -- i.e., controlled burn -- launch is possible.  Next, lets look at the rocket engine.

What about the Rocket to deliver the thrust?

Rocket Engine Testing:

There is extensive testing of the rocket engines which deliver payloads into space.  Regardless of whether the payload has humans on board or not, the cost is easily seen into the billions of dollars.  Therefore, there should be no surprise at the extensive tests which have to be done before the final rocket goes into space.

Where do these tests occur?

Short answer -- in various places.  Here is a video of a test for the SLS rocket shown vertically:

What is the magnitude of the thrust coming out of the rocket engines?  Around 1,700,000 pounds of thrust -- according to one report.

Here is another test that is done in the desert for a similar system shown below:

If you look closer to the flame, you might be able to see the "compression vibration overtones" -- shown in the NASA recorded video below:

You get the point.  The thrust required to generate an escape velocity of around 7 miles per second is huge.  A significant amount of testing has gone into the space flights over the years.  Couple these videos to the reduction in cost of technology due to advances in materials science.  This relationship gives rise to the reduction in cost projected to get a group of civilians to into space -- not to mention the routine shipping and receiving supplies to the International Space Station.  What is my point?

How does a person visualize the magnitude of the thrust in the rocket tests above?

In order to do so, a metric would be needed.  What kind of metric would serve us to really drive home the point? How about a freight ship?  Lets entertain the idea of the possibility of strapping on the 'two-stage' rocket of the Falcon 9 (that exploded) onto a cargo ship (freight ship).  If the thrust that drives a rocket into space was concentrated onto the back of a fully loaded cargo ship, then the question would be:

With the equivalent thrust of a rocket engine, how fast would the freight ship travel?

Below is the analysis -- enjoy!

A Rocket Powered Freight Ship?

I wrote a post regarding the timeline of the popular news cycle and disasters such as ships running aground on reef's, etc.  The point the post was to highlight the magnitude of such a disaster and how long the timeline is to return to normal business.  In the post, I used a disaster that occurred 5 years ago when the M/V Rena freight ship ran aground a reef.  To drive my point home, the salvage of the ship and cargo have just recently been accomplished.

Additionally, I wanted to point out that the enormous amount of cargo that is able to be carried by gigantic ships contribute to the timeline of returning the ship to normal operation.

Recently, off the port of Long Beach, a freight ship (Hanjin Greece) was seized to protect the cargo on board against creditors.  The shipping company Hanjin Korea is going bankrupt while their ships are spread throughout the world.  Freight ships vary in weight due to the cargo carrying capacity that they potentially can deliver.  The largest class of container ships (freight ships) are gathered on a list.  Additionally, the largest ships by gross tonnage are compiled on a list too that have some that dwarf the container ships.  Below is a picture of the Hanjin Greece taken from the website "Vessel Tracker":

Why not use the ship for a metric to visualize the magnitude of the thrust coming off of a rocket?

To do so, the ships total carrying capacity needs to be determined.  According to the website "Mariner Traffic," the total gross tonnage of the Hanjin Greece is 114,144 tons.  Wow!   The average speed is around 12 knots.  In order to carry out the dimensional analysis problems, these values will need to be handy.  I will explain shortly.

In order to start the dimensional analysis of determining the possible velocity of the Hanjin Greece using the thrust of the rocket engine from SpaceX, we need to have the value of the thrust of the engine.  According to the official website for the Falcon-9 rocket, the value of thrust is given for each engine along with the burn time.  For the purposes of the calculation, I will use the value of the first stage engine -- which is equal to 7,067 kiloNewtons of thrust -- Wow!

To determine the velocity, we need to have an equation which relates "horse-power" to force.  Power is expressed as the work divided by the amount of time -- in equation form as follows:

Previously, in a post, we looked at the amount of energy (in power) that is contained in a 'kiloton' of energy -- a nuclear weapon.  In a follow-up post, the amount of energy contained in a '13-kiloton' force was investigated - how to visualize the force. The combined content (information) in the two posts set the stage for the derivation of 'horse-power' (power) from a 'force':

How do we determine the amount of work needed to get the freight ship moving toward a certain velocity?

Work is defined as a 'force' over a given distance.  Substituting "Force x distance" into the equation for power stated above gives the following modified equation for power:

In order to determine the velocity, the last step in the derivation involves the substitution of velocity "v" in for "distance/time" to arrive at the following expression for power:

Now, an expression exists for power that has the two relevant parameters: force and velocity!

To calculate the force to move the ship, the following expression is used for force:

Fill in the cited values for the Hanjin Greece ship and the constant for the acceleration of gravity to yield:

Next, to determine power, the conversion from units of "knots" to "meter/second" needs to be accomplished.  I decided to ask Google and got the following answer shown below:

Plugging in the value of 6.2 meter/second for the velocity gives us the following power required to move a ship weighing 114,144-tons at a speed of 6.2 meter/second:

To power the boat which weighs 114,144-tons at a velocity of 12 knots (13 miles/hour) or 6.2 meters/second costs around 6.3 billion Watts.  Now that we know the amount of power needed to operate a ship at a given velocity, lets review the initial question regarding the thrust of a rocket.  First, the definition of thrust might be useful.  According to Google:

If the power to push the ship with a given thrust is to be determined, then the velocity possible is needed.  Instead of determining a velocity, how about comparing the relative distances are possible with a given power?  To start with, a rocket engine can burn for around 162 seconds.  If a ship that weighs 114,144 tons were traveling at 6.2 meter/second, the possible distance traveled is calculated below:

What does the result mean?  At an top speed of 6.2 meter/second, the cargo ship fully loaded will travel 1001 meters.  As I was writing the blog, the question of the blog changed to the following:

What is the relative distance of the cargo ship traveled powered by the rocket engine?

To answer the question, we start by setting the powers equal to each other as follows:

Next, expressing power in terms of a force applied over a distance in a given amount of time.  That is, the amount of work in a given amount of time.  The expression now appears as follows with each side having a subscript letter "b" for "boat" and "r" for "rocket":

Notice that the variable "t" has no subscript.  Meaning, the amount of time is the same.  The rocket engine provides 7,067-kiloNewtons of thrust for a total of 162 seconds.  The following expression is obtained with the relative forces (boat and rocket) in a given time is shown below:

Expressing an equation with two unknowns makes little sense.  Right?  Well, in the above equation leaving the two distances undefined is an exception.  The above equation holds the answer to the blog post.  In the last line, I have expressed the ratio of the two distances: 1) the freight ship travels at 6.2 meter/second and 2) the thrust of the rocket in the 162 seconds of operation -- to yield the result of 144.

What does 144 mean?

The result is that if the rocket ship was employed to push a fully loaded freight ship, the distance traveled in a total of 162 seconds would be 144 times less than the distance traveled in 162 seconds at a velocity of 6.2 meter/second.

Result: In 162 seconds, the freight ship would travel just over 6 meters compared to 1001 meters at 6.2 meter/second.


Sending space ships into outer space is an amazing accomplishment.  What is interesting to me is that NASA has successfully launched a considerable number of missions over the last few decades.  Now, with the decline in funding for NASA and the conversion of funding coming from the commercial sector, the number of accidents has started to increase.  Maybe, Elon Musk should consider standing back a little and reviewing successes and failures before charging forward.  A small amount of "theoretical optimization" might be of use in the current situation.

So far, there have been disasters in his car company which have resulted in the loss of life.  Hopefully, there will be no loss of life in his space ship missions.  As I have shown in this blog post, the amount of force is three orders of magnitude less than that required to power a freight ship at top speed of 13 miles per hour.  Of course, the considerations are completely different.  The point is that with the different considerations, the timelines should correspondingly be different too.

The space industry is not large.  In fact, according to some accounts, the previously employed NASA engineers have been employed in the commercial space industry.  Since that is the case, coupled with a "new perspective" of the power involved in sending the rockets up into space (as a result of the calculations), we (the public) can demand that the commercial sector change its ways.  The result should be a less reckless commercial industry.  Until next time, have a great day!

Thursday, September 1, 2016

How Much Weight Can The Average Freight Ship Carry?

The news cycle is fast in this world.  Disasters stay in the news a few days -- if the damage is truly extensive.  The recovery from disasters can be long and arduous.  Even though the story might disappear from the news feed, the work to recover might be months or years depending on the extent of the damage.  An immediate example that might come to mind is the recovery from the flooding that occurred recently in Louisiana.  I wrote a blog post regarding the 256 billion gallons of rain that the region received.  On the other end of the spectrum might be the oil rig that recently floated ashore in Scotland -- which I write about here.  Lets explore an intermediate example in the blog post below.

Take for example the following picture shown below:

The image above obviously conveys a major problem that needs to be dealt with.  The picture above is taken from an accident in 2011 -- where the freight ship "Rena" got stuck.  Normally, we would expect to see the following picture of a freight ship shown below:


Or parked in a port ready to be either unloaded or loaded like the ship below:

Returning to the first picture, when a disaster occurs like the one shown above, how does an organization (International, Federal, State, etc.) deal with the problem?  What do you do to remedy the situation?  Obviously, there is a tremendous amount of weight stored on the cargo ship.

Why do I ask such questions?

Cargo On A Freight Ship

The reason that I am interested in asking such questions is due to the "noise" created by the "news" coupled with a devastating disaster -- whether the disaster be natural or man-made.  The "noise" is the news cycle which has reduced the average person's attention span by having us jump from disaster to disaster.  In the example above, the freight ship is stuck in the ocean on a reef.

If an average viewer was to follow just the news cycle, then they might be under the impression that the freight ship was fixed immediately and went back to business as usual.  Through entertaining the amount of weight that an average freight ship might carry at a given time at sea, the perception might be changed.  Or at least updated with further information on which to base an opinion on.

I have been wondering the answer to this question for a long time.  Every time that I see a picture of a freight ship either at Port or out to sea -- I am stunned by the magnificent feat this must be to carry such an enormous amount of weight in a given trip.  A few weeks ago, I was surfing my Instagram account (@mike_thinks_photos) when I happened to run across a picture of a freight ship and was held in amazement once again.  I decided to ask a few question as shown below:

The conversation was attached to the photo shown below:

I cannot wrap my head around a ship (like the one above) carrying a payload of 180,000-tons.  WOW!  That is too much for me to comprehend.  The reason why is based on a previous post that I wrote about the relative weights of the Queen Mary Ship and the Spruce Goose airship created by Howard Hughes.  In that post, the conclusion was drawn that the erroneous excerpt from a tour guide mistook the weight of the Spruce Goose to be 400,000 tons (which was completely off base).  Why?

If that were the case, then the Queen Mary Ship which is pictured below and weighs 96,000 tons would be roughly 1/4 of the weight of the Spruce Goose -- which clearly is not the case:

Source: Wikipedia

Here is another view of the Queen Mary Ship along with the dome which houses the Spruce Goose airship shown below:

Further, if this were the case, then the Spruce Goose would go down in history as the most "fuel inefficient" plane in history and would probably have never been able to lift off the ground.   The conclusion of that blog post was that the "units" of measurement -- weights of each object were clearly mistaken by the author and that certainly can make a difference in the readers mind (not to mention the California Tourist eager to see those attractions).

An additional point to note in the example above of comparing the two objects (Queen Mary Ship and Spruce Goose airship) is the weight of each.  If the Queen Mary does indeed weigh 96,000 tons -- then this can qualify as a 'metric' to use in the current post in regards to casting the weight carried on a freight ship into perspective.

A calculation can be carried out by dividing the two stated values of weight by each other.  That is, divide the weight that is possible to carry on a freight ship (180,000 tons) by the weight of the Queen Mary Ship to get the following result shown below:

Which is to say, that the amount of freight (in weight) that an average freight ship can carry is equivalent to nearly the weight of two Queen Mary Ships -- WOW!

No wonder why disasters like the one above where the freight ship runs aground on a reef are so problematic.  Think about the timeline of getting the ship back to moving cargo as usual.  What steps have to be taken to stabilize a ship that is off-axis as shown in the picture (the first picture)?

Here are a few considerations:

1) How does a crew remove cargo from a tiled ship?

2) How does a crew pull the ship back into the water (if possible)?

3) How does a crew inspect ship for damage?

If we just entertain the three considerations above, how does a shipping company proceed with such a disaster?  If anyone reading this blog post works for a shipping company, please feel free to comment below and give us some insight into the matter.  Seems like an impossible task to me.  I would have the following questions of concern:

1) What happens if the ship moves while removing the cargo?

2) What happens if the cargo falls off the ship while attempting to extract the freight?

3) What happens to the workers aboard the ship while the cargo is being removed?

4) Where is the extracted cargo moved to -- another ship?

Wow! 180,000 tons is equal to nearly two Queen Mary Ships.


The next time that you see a freight ship like the one shown below:

Stop and entertain the following thought: The amount of weight on that ship could equal nearly two of the ships shown in the picture below:

Furthermore, take a little time to ponder the amount of effort which would be required of salvaging crews to fix a freight ship that had floated ashore or onto a reef (like Rena above).  Additionally, think about the importance of trade routes throughout the world (Suez Canal, etc.).

Why are those shipping routes so coveted?

When the issue is cast into the metric of the amount of weight possible to carry, the problem is quite simple.  The next time that the popular news is filled with "noise" regarding dock workers striking at the Ports which house these ships, stop and think of the volume of cargo that is being held up from moving about the world.  Think of the packages and goods that are being stalled on ships that are waiting at sea to be unloaded.

The above weight mentioned did not include the thousands of tons of oil which was stored on the ship to power the movement of the cargo on route.  Until next time, have a great day!!