pH System Modeling and Control

PH ScaleWhen dealing with acids and bases, the subject of pH and pH control often comes up. In this post we'll discuss some methods of modelling acidic and basic streams and talk a little about the practical difficulties in controlling pH in the real world.

pH, you’ll hopefully recall, is a logarithmic measure of the activity of hydrogen ions in a solution. For plain water a pH of approximately 7 is “neutral” or natural water, with lower numbers being acidic and higher numbers basic.




 Modeling Mixtures of Acids and Bases

For simple mixtures of acids and bases, this online calculator lets you predict the pH of a mixture. Before starting the calculator, you must either know the concentrations of the acid and base in the total solution after mixing (see their example Case #1), or the concentrations and flowrates of the acidic and basic streams before mixing (see Case #2).

WebQC pH Solver

Let's try this out! For example, say I have a mixture containing 0.1 mol/L of HCl and of NaOH:


HCL pKa=-7.0 c=0.1

NaOH pKb=0.2 c=0.1 Continue reading

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Free and Legal Access to MS Word, Excel, Office

Using VLOOKUP in a calculation or list

Light users can save themselves $100 with these resources. (Curious what I'm doing here?)

Need to get access to Microsoft Office for a new PC, but don’t have the cash on hand to get the latest version just yet? Try these free and legal options:

  1. Microsoft Starter 2010 – Free "light" versions of Word and Excel. This software was originally pre-installed into certain laptops and computers. Intended for Operating Systems earlier than Windows 8, only. It won’t have all features, for example you can’t run Macros in Excel, and it has a mandatory ad in the corner taking up screen space. But it can do in a pinch. Intro to Excel Starter, Missing features
  2. Open Office, a freeware alternative
  3. Libre Office, another alternative

Open and Libre office are very comparable to each other in features. They replicate almost all of office, but you may feel the absence if you run a lot of Macros, Excel Add-ins, etc.

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Chemical Plant Safety Tips Easily Forgotten

Today, a handful of safety lessons which are easy to forget when visiting a chemical plant:

Dangerous chemicals:

And I thought they smelled bad...on the outside!

What if you didn't have the goggles?

  • Every plant worth its salt will have Material Safety Datasheets (MSDSs) in prominent locations, and proper training, for each hazard. These sheets provide specific guidance on to do if you’re exposed to the chemical and advice for dealing with fires. Training on how to use MSDS sheets is ubiquitous and it should be easy to get some, if you didn’t gain experience with these sheets while getting your degree
  • If you are ever exposed to a “mystery chemical,” a good rule of thumb is this: if exposed in your body/eyes, run for a safety shower/eye wash station and wash your body/eyes out thoroughly, for up to 15 minutes, while calling someone else to get help. When showering, remove exposed clothes as they may be contaminated. Do not induce vomiting. There are plenty of exceptions where this is unnecessary or even dangerous, which is why you check the MSDS first. But this is a typically the right response
  • If the work you are doing means that you may need to use an eyewash station, prepare before you start working. Stop yourself and visualize in your mind how you can stumble to the eyewash station while blinded. What direction can you head for? What wall will you feel along? Etc.
  • If a site has multiple chemicals, don’t mix and match Personal Protective Equipment (PPE) from different zones. For example, there are specialty gloves that can stand up to pools of ultra-dangerous Hydrogen Fluoride for over an hour, yet disintegrate in face of deadly deadly mayonnaise

Respirators: Continue reading

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Why American Women Graduates are Quitting Engineering

Rani Bokar at Intel

Rani Bokar leads the team at Intel

So I dug into another "women in engineering" report, trying to see if anyone had cracked the code on why women tend to leave engineering 2-3x more often, despite being just as qualified. It's a 64-page review of graduates all over the United States: Stemming the Tide Why Women Leave Engineering (PDF). This is more about keeping women in the field, not getting them to consider it as an option in the first place.

Some quick hits on the findings, I am mashing up those who leave before and shortly after entering the workforce here:

  • No difference in demographics, confidence, attitude, GPA, major/discipline of those who stay and leave. It's mostly the specifics of the jobs they find and the climate they find
  • 60-80% who leave field are still working, but elsewhere
  • Setting aside the people who don't find engineering interesting, and main issues are roughly:
    1. 50%: Working conditions -poor training, too much travel
    2. 30%: Work "climate" -  a "work 60 hours a week paid 40" sweatshop or a sexist attitude among the office
    3. 25%: Family reasons and just general work/life balance
  • Recommendations start page 57: Better organizational path, training, positive climate, mentors, reasonable work-life balance. Mostly of it's pretty obvious stuff

I notice that once again, the vast majority of graduates and employees are in chemical, civil, and mechanical engineering. As I've mentioned, this is a highly consistent and statistically huge trend (at least in North America) and I cannot find any discussion of why those disciplines appeal so much more to women. Leave a note in the comments if you have any info!

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Mastering B2B (Business to Business) Sales

Are they ordering widgets out of a catalog, or can you show them a burning need for change?

Are they ordering widgets out of a catalog, or can you show them a burning need for change? (Credit Jim Larrison)

B2B is where one company tries to a product, service, software, or system to a different company. Equipment vendors, consultants, and software developers will all want to check out this article I found. The End of Solution Sales, in the 2012 July/August issue of Harvard Business Review.

I will try to summarize briefly. The authors basically argue that the old way of making B2B sales is inefficient, and that their research suggests a new style called “insight selling” that the top 10% of salespeople are using.

The “old style” of sales is basically:

  • First find prospect companies to sell to. The best organizations are large/moneyed, have a clear vision or business plan, have identified problems that are related to your company’s area of business, and have a stable procurement process so they are used to purchases and contracts
  • Find contacts in the client company who are accessible, talkative, honest, good listeners and speakers, and stand to benefit personally if your sale succeeds
  • Talk to them about their problems, and fish for places where you can “hook” your services or solutions into their problems
  • Once you’ve got an area you can help solve their problem, win over your contact, and then help them make the sale. Ask questions and try to find out about the client’s procurement practices, then help your contact steer your solution through the process. (By giving them info to answers questions, showing up to meetings, meeting the various people who need to sign off on it, etc.)

This is certainly not bad advice and with the right personalities makes for a decent sales force. The problem is that with the proliferation of easier information (Internet) and globalization, customers are savvier than ever. Instead of having a problem and needing a salesperson to come riding in with a solution, established customers probably have a solution clearly in mind and have researched 3-5 firms that can do it. You end up coming into a “request for proposal” (RFP) situation, where the client basically has a contract already in mind and is asking you to bid against your rivals. Now you’re fighting price wars to win small, pre-defined slices of work.

Instead, the article proposes insight selling, where you: Continue reading

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