Beware of shipping revenue-generating parcels by USPS

The United States Postal Service is great for two reasons. First, for a couple quarters a letter can be sent across the country. Second, books, and other media free of advertising, can be shipped nearly anywhere for barely more than fifty cents a pound. The drawbacks of the USPS include stuffing your mailbox with rainforests worth of direct mail, providing no real service in the event of a lost package, barraging website users with a spammy array of services during a simple address change, charging for sundries like paper and tape at their retail locations, and many others that I’m sure Americans of all stripes can come together and complain about. However, I was a little bit surprised to find a new one today.

Over the course of my life I have gradually been acquiring books more quickly than I get rid of them. Some are great novels I’ve read, some are textbooks from college or grad school, some a books I never read about a subject I wanted to learn about, and some are on the to-read list. No matter how fast I give away books, I always seem to continue accumulating them. This presents a problem each time I move.

For my current transition from Atlanta to Berkeley, I decided to ship my collection via media mail. I calculated I had about 300 pounds of books I wanted to keep, so USPS would charge me about $150 to move them all. Not bad. I then figured that since I was shipping books, I may as well ship all my stuff. I went to my friendly local Midtown ATL post office this morning with 10 small (16″ x 12″ x 12″) Home Depot boxes plus a few others.

First I was informed that each USPS customer can only ship 10 packages per day! Huh? I would love to know if this is actually true and, if it is, what kind of insane business wants its customers not to use its services. However, my clerk bent the rules for me and agreed to ship all 12 of my packages as long as I rewrote all the address labels.

Then came the prices. Media Mail was about $0.50 per pound, as expected, but by non-media boxes rang up at almost three times the price without tracking, insurance, or any other niceties included with competitors’ rates. I know USPS loses money on first class mail and media mail, but I would have thought that their destructively cheap behavior at the retail locations and direct mail cash cow would let them charge competitive rates on regular shipments. I was wrong.

For a 50 pound 16″ x 12″ x 12″ package going from Atlanta to Berkeley insured for $500, USPS charges $92.70. FedEx Ground only charges $68.46. I had looked up the FedEx Ground rate before walking in and would have assumed USPS would have parity, but realized I was totally wrong as my first non-Media Mail package got rung up. The fact that USPS is so uncompetitive (35% more expensive!) was really surprising to me. In fact, given how many packages I had, the dramatically higher rate drove me right to the FedEx office down the street.

I realize the government holds down First Class Mail and Media Mail rates and direct mail is an important revenue generator for the USPS, but the fact that they can’t compete on regular parcel price while offering a significantly worse experience to most customers was very surprising for me. I don’t know what the solution is to improve the USPS experience, but given the current letter volume, distaste for mass mailings, and excellence of FedEx and UPS, I think the time may soon come to pull the plug.

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I happily landed at 3D Robotics in beautiful Berkeley, CA

About a month ago, I accepted a dream job with 3D Robotics to develop their first enterprise product. This is an amazing opportunity for me as I’ll be able to apply skills I learned from Exponent, Agribotix, and the Anseth Group to building an unmatched enterprise offering that will allow businesses to keep workers out of harms way and save time and money. Stay tuned for updates as they come.


Tales from the trenches: Polymer science in the real world

After graduating with my PhD in Chemical Engineering, having spent four years studying the mechanical behavior of polymer networks, I thought I knew something about polymer science. I was wrong. Terribly wrong.

I’ve now spent the last six months working in the polymers and materials practice at a technical consulting firm, Exponent, where I have been exposed to a couple dozen real-world polymers problems in industries ranging from oil and gas to biomaterials to performance textiles. Throughout this process, I’ve learned so much that I wish I had known when making the transition from academia to industry. I would like to share some of my top lessons with you here today. This is directed primarily at graduate students or postdocs in chemistry, chemical engineering, or materials science interested in a career in the polymers industry, but I would love to get feedback from industry veterans.

Lesson 1: Your research matters
Halfway through a tedious column separation that may have yielded monomers that may have polymerized into a new material that may have had interesting properties, it was very difficult for me to justify my graduate research. Since coming into industry, and particularly consulting, where we draw on an enormous number of sources, I have recognized the tremendous value of fundamental “low-impact” studies. Recently, I helped a major biotechnology company optimize a part of its manufacturing process by looking up some rates I published in graduate school (that were incredibly boring to collect, I might add) and have experienced many more examples to that effect. I scour the literature daily for tables of values that are frequently published in obscure, low-impact journals, but are none the less incredibly valuable. This may be no consolation while slaving over a column at ten o’clock at night, but someone, somewhere will use your research for something very valuable. As a current member of the chemical industry, I would like to see more, not less, papers characterizing materials or reactions in detail, and more tables like the one below showing the rate of an nitro group reduction by ammonium formate (Siya Ram and Richard E. Ehrenkaufe, Tett. Lett., 1984)

Table of nitro reductions

Lesson 2: Industry is 50 years behind academic research
Academicians are conditioned to justify their research in practical terms. I know from my own experience in writing and reading papers that even the most fundamental, basic research result is often oversold as having the potential to revolutionize human health, energy, biofuels, or whatever the cause du jour is. Unfortunately, these academic results virtually never translate to industrial or commercial success. Polymer scientists in the biotech industry may be further ahead of the curve than those in specialty or commodity polymers, but, in nearly all cases, industry works about 50 years behind academic research. A concrete example: one would think that, with all the exciting biomaterials research out there, medical devices would be biocompatible, functionalized, resorbable, and, well, advanced. The truth of the matter is that the vast majority of medical devices are still polypropylene, polyethylene, PET, and other commodity polymers sourced from major petrochemical companies. The Ethicon (J&J) mesh below is very commonly used to repair hernias and is a simple structure composed of knit polypropylene fibers.

ethicon mesh

Lesson 3: Industrial characterization techniques are rarely seen in academic labs
MFI, DSC, FTIR, TGA? Specific gravity, brittleness temperature, melt flow, elongation at break? This alphabet soup of instruments and subsequent list of material properties is probably vaguely familiar to academic polymer scientists, but represent the bread and butter of industrial characterization. If someone had told me last year that the most common technique for characterizing commodity polymers was melt flow index (MFI), which involves heating a sample and weighing how much flowed through a capillary in ten minutes, I would have been in disbelief. In a 21st century university lab we are surrounded with rapid, accurate characterization instruments like NMR, MALDI, HPLC, and GPC, so why on earth do people in industry use antiquated techniques and standards? The answer is part momentum, part ease of use and cost. An FTIR spectrum, which is one of the most illuminating techniques commonly used in industry, provides much of the same information as an NMR, but is cheaper and requires no solvents or sample prep to collect. A melt flow instrument is shown below. Notice how simple is it relative to those more commonly used in academic settings.


Lesson 4: Trickle-down technology in the polymers industry
The polymers industry is far more similar to any other big, slow sector like packaged foods or automobiles than I ever imagined in graduate school. The commodity polymers, which represent an enormous chunk of the plastics in use, are largely made by a select few players (BASF, ChevronPhillips, Exxon, etc.). These companies sell their resins or resin formulations that include additives and fillers optimized for specific end uses to either reformulators or manufacturers, in the case of very simple applications like plastic bags. The reformulators then add their secret blend of additives and fillers and relabel the product, usually without identifying the original source. These resins then either get resold and reblended again or processed into a product, which is never linked to the reformulator, much less the original manufacturer. Throughout this process, polymer scientists at each stage, aside from the first, often have little idea as to exactly what polymers, additives, or fillers are present and in what quantities. Decisions are commonly made based on the advice of the sales rep providing the material. This secrecy and trust seemed crazy coming from an academic background, but often decades of optimization has gone into particular resins and it can be very difficult to find the person who knows exactly why each component is present. The image below, from NatureWorks/Cargill, the largest US manufacturer of poly(lactic acid) resin, shows how many steps a polymer resin takes to make it into a consumer’s hand.

NatureWorks value chain

Lesson 5: Industrial polymers products are not identified by their composition
Academic scientists get very good at elucidating material properties and behaviors based on chemical structure. I know in grad school I would occasionally just browse the building blocks section of the Sigma catalog and imagine what types of materials I could make. This never happens in industry. Commercially available polymer resins are defined not by their structure, molecular weight, additives package, fillers, or any other rational, easy to understand metric. Rather, they are sold based on their properties, e.g. melt flow, tensile strength, specific gravity, elongation at break, or others. This can be infuriating for someone accustomed to the openness of academia, because it is often impossible to learn the exact composition of a particular resin without time-intensive reverse engineering.

PET structure and properties

Lesson 6: Fillers and additives are the name of the game
In academia, the focus is almost always on the polymer. Researchers are constantly developing new polymers, new crosslinking chemistries, and new applications. I don’t recall reading a single paper in grad school on polymer additives. In industry, that emphasis is reversed. Polyolefin resins must contain antioxidants for environmental stability, rubbers must contain silica particles to improve life, and vinyl resins must include plasticizers to reduce brittleness. Every plastic consumer product contains an array of fillers and additives to either improve properties or reduce costs. These additives range from small molecules like hindered amine light scavengers to inorganic fillers like calcium carbonate to natural fibers like cellulose. Reformulating polymer resins into useful, cost effective materials is one of the most important areas of polymer science and a very active area of industrial research. Below is a a macro and SEM image of a glass fiber-based polymer filler (Ardavan Yazdanbakhsh and Lawrence C. Bank, Polymers, 2014).


I am officially an Engineer in Training (and tips for getting there from a non-traditional background)

Coming from an undergraduate background in Physics, I had never been introduced to the concept of a Professional Engineer (PE) license. In my first year of grad school, one of my colleagues in Chemical Engineering had recently gotten his and I saw the letters PE dangled behind names every now and then, but, even after graduating with my PhD in Chemical Engineering, I still had very little idea how or why one obtained a PE license.

That all changed once I started at Exponent. Regardless of background, earning a PE license is strongly encouraged at Exponent and a cursory glance through the consultant roll call ( confirms that many follow through. While a PE license is generally not required or even beneficial for engineering working in industry, which includes essentially all Chemical Engineers, it is required for most independent work and strongly recommended for consulting. This is driven by the litigious nature of much of Exponent’s work. Attorney’s will frequently grill experts on qualifications and certifications, and obtaining a PE license strengthens credibility in the eyes of many in the legal system.

That said, despite my non-traditional background, sometime in August I started the ball rolling to get my PE license. The first step to become an Engineer in Training (EIT). In order to become an EIT, one must have four years of experience in engineering and pass the Fundamentals of Engineering exam administered by NCEES ( It turns out that both of these steps became hurdles for me.

First, the experience. While NCEES administers the FE and PE Exams, the actual licensing process is done through the State Department of Regulatory Affairs (Colorado DORA for me). These folks are seriously overworked and dealing with non-traditional educations is a total pain for them. A typical examinee with a 4-year, ABET accredited, engineering undergraduate degree has no problem sitting for the FE exam immediately after graduating or even before in some cases. An atypical examinee, with a 4-year Physics BA and Chemical Engineering PhD like, has a much more difficult time. I had to negotiate with DORA for something like 3 months before I could get approved to take the FE Exam. A tip for those in similar situations: be persistent and polite. the DORA staff is overworked and determining engineering experience is not something they want to spend a lot of time on.

The second hurdle is the FE Exam itself. For Chemical Engineering, the exam has something like an 80% pass rate. I don’t think I’ve been in the bottom 20% of anything I’ve even done in my life, so I just registered and reasoned I didn’t need to study. I was wrong. This is a bad idea. Luckily, two weeks before I was scheduled to take the exam, I logged in to the NCEES practice exam online and was humiliated. Despite flying through my graduate ChemE coursework, I had absolutely no idea how to do how to do the undergraduate ChemE problems that were found on the exam. No idea. I scored less than 50% on the practice exam, nailing essentially on the math problems and the problems that could be reasoned out using units alone. Despite some reports on the internet, I wasn’t confident that 50% is a passing score and would have been terribly embarrassed if I failed. I found myself with two weeks to teach myself all of undergraduate Chemical Engineering.

I had two weeks to learn the fundamentals of fluids, thermodynamics, heat transfer, mass transfer/separations, engineering economics, and controls. To do this, I would recommend one resource and one resource only– Faculty at the University of Colorado have invested significant time into distilling the fundamentals of Chemical Engineering into easy-to-digest, 5-20 minute videos and have outlined a series of videos designed specifically for studying for the FE Exam. Those two weeks before the exam, I got up a little earlier every morning before work, watched a video or two, and diligently repeated until exam time came. And, it worked! While I was previously a little embarrassed in grad school having no idea how to read a McCabe-Thiele diagram or calculate flow losses through a pipe, after 15-20 hours of studying, I now would feel totally confident teaching these undergraduate courses.

Despite the headaches that came with it, I am now proud to call myself Colorado Engineer in Training #71087. Now I just have to wait 6 years to take the PE exam…


Congratulations to Nobel Laureates Shuji Nakamura and Eric Betzig

I was briefly at UCSB in 2009 and everyone on campus involved with the Material Science Department admired Shuji Nakamura, both for his kindness and likelihood of winning a Nobel Prize for his seminal work in developing the blue LED. While green and red LEDs had been around for some time, without blue there was no hope of replacing many types of lights with these energy efficient solid-state devices. Shuji’s work enabled LED light bulbs, which I absolutely adore, televisions, and other devices in addition to generally advancing our understanding of advanced materials. While I never met the man myself, I’m happy that such an admired researcher took home the Nobel Prize in Physics.

Eric Betzig earned the Nobel Prize in Chemistry for his work in super resolution optical microscopy. He holds a special place in my heart for several reasons. First, as an HHMI Investigator, he was a member of the same tight knit club that counted my graduate school advisor, Kristi Anseth, among its ranks. HHMI is a tremendous organization and I am proud to have done my graduate research in an HHMI lab. The organization has generated a Nobel Prize in each of the last three years and I look forward to many more. Second, he gave a tremendous lecture at the University of Colorado shortly before I defended, so I had the opportunity to learn more about his research in person. And finally, I spent many hours pushing the limits of confocal microscopy in graduate school and I’m happy that innovation in the area is being rewarded.

However, all is not well with the round of Nobel Prizes. In my short-lived time at UCSB, I spent most of my time in the lab of Galen Stucky, who is best known for his pioneering work on mesoporous zeolites. I was excited to read in C&EN that Galen was on the short list for the chemistry Nobel, but I have to admit, despite my appreciation of Eric’s work, that I would have preferred to see Galen on a flight to Sweden. Notwithstanding, congratulations to all the Laureates and I will in anticipation for Galen’s prize next year. In his honor, the structure of a zeolite appears below.


What now?

After four years in grad school, it can sometimes be a little strange to exit into the real world. Grinding through a PhD taught me far more than how to direct my own basic research. I developed leadership skills mentoring high school students, undergraduates, and junior graduate students. I developed communications skills teaching and presenting at conferences. I developed business skills competing in the University of Colorado New Venture Challenge, which just kicked off. And more than anything, I learned about working smart and not hard.

So where am I taking these skills? Dearest to my heart is Agribotix. As my readers have learned, Agribotix is a drone-based remote sensing company that provides actionable intelligence to farmers. We are just wrapping up a phenomenal first growing season where we provided data on more than one billion corn plants to dozens of growers and look forward to beginning to ramp up in the Fall. Fundraising efforts are just beginning to kick off and we are seeking at $2-3M initial round. While I am no longer full time at Agribotix, I am still deeply involved and have confidence that amazing things are coming.

Second, I am in the midst of writing a guide/memoir covering getting a PhD in the hard sciences. Based on my experiences and those I read about online, the vast majority of PhD students (including me, when I started) have very little practical information about how to succeed in graduate school. This ranges from where to apply, to what department to choose, to project and advisor selection, to day-to-day research, to post-graduation plans. I will be posting chapters here periodically and would love nothing more than to give back to a current crop of graduate students. I learned so much over that I would be more than willing to share before the book comes out, so please reach out if you are currently pursuing a PhD in the hard sciences and would like a totally objective, practical viewpoint.

Finally, in mid-August I began working in the Polymer Science and Materials Chemistry Practice at Exponent, the leading scientific and engineering consulting firm. The projects that have come through since I began have been a riot and it’s been really illuminating to learn how polymer science happens in the real world. In the next few months, after I have a little bit more experience under my belt, I will put together a presentation designed for current graduate students in the polymer/materials area to share what I wished I knew before beginning to work in industry. I’m also busy studying for the Chemical Engineering Fundamentals of Engineering Exam, which will be slightly more challenging than I anticipated because my undergraduate degree is not in Chemical Engineering.

That said, this website will undergo somewhat of a pivot in the next few months from primarily being designed to share my graduate research to, ideally, becoming a source of information for current and prospective graduate students. I learned a lot from my mentors throughout my studies and would like to take this opportunity to give back. I will try to write blog posts every week or so sharing some practical polymer science tips, excerpts from my book, and general commentary on the chemical and materials industries.

In the meantime, if you are a PhD or soon-to-be PhD student in the hard sciences, I would recommend checking out Philip Guo’s free E-book, The PhD Grind. Philip is in a more unique position than most graduate students, having graduated from MIT with a Computer Science Bachelor’s Degree and from Stanford with his Doctorate, but his book provides and honest look at life as a graduate student.

And finally, I am now in beautiful Atlanta, Georgia. I will write more about this later, but the city seriously need a PR department. Prior to arriving in Atlanta, I heard nothing but bad things, but this is an amazing city. A view of where we live in Midtown from the park next door is posted below.

Midtown from Piedmont



My final paper from graduate school, “Measuring Cellular Forces Using Bis-Aliphatic Hydrazone Crosslinked Stress-Relaxing Hydrogels” published in Soft Matter

My final paper from the Anseth Group was just published in Soft Matter. It represents the culmination of the last few years we spent developing and characterizing bis-aliphatic hydrazone crosslinked hydrogels and demonstrates, in my opinion, a really clever application for the materials. Have a read here at See the abstract below:

Studies focused on understanding the role of matrix biophysical signals on cells, especially those when cells are encapsulated in hydrogels that are locally remodelled, are often complicated by appropriate methods to measure differences between the bulk and local material properties. From this perspective, stress-relaxing materials that allow long-term culture of embedded cells provide an opportunity to elucidate aspects of this biophysical signalling. In particular, rheological characterization of the stress relaxation properties allows one to link a bulk material measurement to local aspects of cellular functions by quantifying the corresponding cellular forces that must be applied locally. Here, embryonic stem cell-derived motor neurons were encapsulated in a well-characterized covalently adaptable bis-aliphatic hydrazone crosslinked PEG hydrogel, and neurite outgrowth was observed over time. Using fundamental physical relationships describing classical mechanics and viscoelastic materials, we calculated the forces and energies involved in neurite extension, the results of which provide insight to the role of biophysical cues on this process.

McKinnon Soft Matter TOC

My Biomacromolecules entitled, “Design and Characterization of a Synthetically Accessible, Photodegradable Hydrogel for User-Directed Formation of Neural Networks” out on ASAP

In this paper, Tobin Brown and I developed and characterized a synthetically tractable photodegradable hydrogel and demonstrated the ability to control the extension of motor axons. Check it out at The abstract appears below:

Hydrogels with photocleavable units incorporated into the cross-links have provided researchers with the ability to control mechanical properties temporally and study the role of matrix signaling on stem cell function and fate. With a growing interest in dynamically tunable cell culture systems, methods to synthesize photolabile hydrogels from simple precursors would facilitate broader accessibility. Here, a step-growth photodegradable poly(ethylene glycol) (PEG) hydrogel system cross-linked through a strain promoted alkyne–azide cycloaddition (SPAAC) reaction and degraded through the cleavage of a nitrobenzyl ether moiety integrated into the cross-links is developed from commercially available precursors in three straightforward synthetic steps with high yields (>95%). The network evolution and degradation properties are characterized in response to one- and two-photon irradiation. The PEG hydrogel is employed to encapsulate embryonic stem cell-derived motor neurons (ESMNs), and in situ degradation is exploited to gain three-dimensional control over the extension of motor axons using two-photon infrared light. Finally, ESMNs and their in vivo synaptic partners, myotubes, are coencapsulated, and the formation of user-directed neural networks is demonstrated.