Here's my new GeoGebra app

The post GeoGebra app Feb 2024 appeared first on Hoitsma Blog.

]]>Civil Engineering

Smeaton was the first self-proclaimed “civil engineer”, and is often regarded as the “father of civil engineering”.

In his 1759 paper “An Experimental Enquiry Concerning the Natural Powers of Water and Wind to Turn Mills and Other Machines Depending on Circular Motion” Smeaton developed the concepts and data which became the basis for the Smeaton coefficient, the lift equation used by the Wright brothers.

Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755–59).

Smeaton is important in the history, rediscovery of, and development of modern cement, identifying the compositional requirements needed to obtain “hydraulicity” in lime; work which led ultimately to the invention of Portland cement. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton’s influence.

Obviously, a brilliant and energetic man of history.

It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone.

It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available. The most common, called ordinary portland cement (OPC), is grey, but white portland cement is also available.

Its name is derived from its resemblance to portland stone which was quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of “modern” portland cement due to his developments in the 1840s.

The term portland in this context refers to a material or process, not a proper noun like a place or a person, and should not be capitalized.

Cement production contributed about 8% of all carbon emissions worldwide, as of 2018.

Stone has been quarried on the Isle of Portland since Roman times and was being shipped to London in the 14th century.

Extraction as an industry began in the early 17th century, with shipments to London for Inigo Jones’ Banqueting House.

Wren’s choice of Portland for the new St Paul’s Cathedral was a great boost for the quarries and established Portland as London’s choice of building stone.

The island was connected by railway to the rest of the country from 1865. Albion Stone PLC has been quarrying and mining Portland stone since 1984. Portland Stone Firms Ltd have been quarrying Portland stone since 1994.

https://en.wikipedia.org/wiki/Portland_stone

https://en.wikipedia.org/wiki/Isle_of_Portland

By Wilson44691 at English Wikipedia – Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster).[1], Public Domain, Link

The Lunar Society of Birmingham was a British dinner club and informal learned society of prominent figures in the Midlands Enlightenment, including industrialists, natural philosophers and intellectuals, who met regularly between 1765 and 1813 in Birmingham.

Historians therefore disagree on what qualifies as membership of the Lunar Society, who can be considered to have been members, and even when the society can be said to have existed.

Despite this uncertainty, fourteen individuals have been identified as having verifiably attended Lunar Society meetings regularly over a long period during its most productive eras: these are:

- Matthew Boulton: inventor, mechanical engineer, and silversmith
- Erasmus Darwin: physician, author of
*Zoonomia* - Thomas Day: author of
*The History of Sandford and Merton* - Richard Lovell Edgeworth: politician, writer and inventor
- Samuel Galton, Jr.: arms manufacturer
- Robert Augustus Johnson
- James Keir: chemist, geologist, industrialist, inventor
- Joseph Priestley: discoverer of oxygen
- William Small: physician, professor of natural philosophy
- Jonathan Stokes: physician, botanist, early adopter of the heart drug digitalis (*)
- James Watt: inventor, mechanical engineer, chemist, improved the Newcomen steam engine (1712) with his Watt steam engine (1776)
- Josiah Wedgwood: founder of the Wedgwood company in 1759
- John Whitehurst: clockmaker, scientist, author of
*An Inquiry into the Original State and Formation of the Earth* - Villiam Withering: botanist, geologist, chemist, physician, first systematic investigator of the bioactivity of digitalis (*).

(*) The best-known species of digitalis is the common foxglove, Digitalis purpurea.

The post John Smeaton — "Father of Civil Engineering" Jan 2024 appeared first on Hoitsma Blog.

]]>Civil Engineering

Smeaton was the first self-proclaimed “civil engineer”, and is often regarded as the “father of civil engineering”.

In his 1759 paper “An Experimental Enquiry Concerning the Natural Powers of Water and Wind to Turn Mills and Other Machines Depending on Circular Motion” Smeaton developed the concepts and data which became the basis for the Smeaton coefficient, the lift equation used by the Wright brothers.

Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755–59).

Smeaton is important in the history, rediscovery of, and development of modern cement, identifying the compositional requirements needed to obtain “hydraulicity” in lime; work which led ultimately to the invention of Portland cement. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton’s influence.

Obviously, a brilliant and energetic man of history.

It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone.

It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available. The most common, called ordinary portland cement (OPC), is grey, but white portland cement is also available.

Its name is derived from its resemblance to portland stone which was quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of “modern” portland cement due to his developments in the 1840s.

The term portland in this context refers to a material or process, not a proper noun like a place or a person, and should not be capitalized.

Cement production contributed about 8% of all carbon emissions worldwide, as of 2018.

Stone has been quarried on the Isle of Portland since Roman times and was being shipped to London in the 14th century.

Extraction as an industry began in the early 17th century, with shipments to London for Inigo Jones’ Banqueting House.

Wren’s choice of Portland for the new St Paul’s Cathedral was a great boost for the quarries and established Portland as London’s choice of building stone.

The island was connected by railway to the rest of the country from 1865. Albion Stone PLC has been quarrying and mining Portland stone since 1984. Portland Stone Firms Ltd have been quarrying Portland stone since 1994.

https://en.wikipedia.org/wiki/Portland_stone

https://en.wikipedia.org/wiki/Isle_of_Portland

By Wilson44691 at English Wikipedia – Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster).[1], Public Domain, Link

The Lunar Society of Birmingham was a British dinner club and informal learned society of prominent figures in the Midlands Enlightenment, including industrialists, natural philosophers and intellectuals, who met regularly between 1765 and 1813 in Birmingham.

Historians therefore disagree on what qualifies as membership of the Lunar Society, who can be considered to have been members, and even when the society can be said to have existed.

Despite this uncertainty, fourteen individuals have been identified as having verifiably attended Lunar Society meetings regularly over a long period during its most productive eras: these are:

- Matthew Boulton: inventor, mechanical engineer, and silversmith
- Erasmus Darwin: physician, author of
*Zoonomia* - Thomas Day: author of
*The History of Sandford and Merton* - Richard Lovell Edgeworth: politician, writer and inventor
- Samuel Galton, Jr.: arms manufacturer
- Robert Augustus Johnson
- James Keir: chemist, geologist, industrialist, inventor
- Joseph Priestley: discoverer of oxygen
- William Small: physician, professor of natural philosophy
- Jonathan Stokes: physician, botanist, early adopter of the heart drug digitalis (*)
- James Watt: inventor, mechanical engineer, chemist, improved the Newcomen steam engine (1712) with his Watt steam engine (1776)
- Josiah Wedgwood: founder of the Wedgwood company in 1759
- John Whitehurst: clockmaker, scientist, author of
*An Inquiry into the Original State and Formation of the Earth* - Villiam Withering: botanist, geologist, chemist, physician, first systematic investigator of the bioactivity of digitalis (*).

(*) The best-known species of digitalis is the common foxglove, Digitalis purpurea.

The post John Smeaton — "Father of Civil Engineering" Jan 2024 appeared first on Hoitsma Blog.

]]>AISC Bolt Shear Capacity — Minimum Dimensions

In a June 2019 post, I presented my AISC bolt capacity app. The iPhone app uses Pythonista to calculate AISC bolt shear capacities in accordance with the 15th Edition of the Manual of Steel Construction in accordance with Section J3. The app condenses the use of AISC Tables 7-1 through 7-5 into a straightforward single page app.

Here are a few summary screenshots that present the minimum spacings, edge distances, and plate thicknesses required to achieve 100% of the rated shear capacity of the bolt..

First, compare " bolts — Grade 36 and then Grade 50 plate

Second, compare ” bolts — Grade 36 and then Grade 50 plate

Finally, compare 1" bolts — Grade 36 and then Grade 50 plate

Of course, it is simple to specify the plate thickness to achieve 100% capacity. However, the beam web may still limit the bolt capacity as in the following example.

Here are a few summary screenshots that present the minimum spacings, edge distances, and plate thicknesses required to achieve 100% of the rated shear capacity of the bolt..

First, compare " bolts — Grade 36 and then Grade 50 plate

- The minimum spacing is "
- The minimum edge dimension is 1"
- The minimum plate thickness is "

I note that a Grade 50 plate thickness of " provides 97% of the rated bolted capacity.

Second, compare ” bolts — Grade 36 and then Grade 50 plate

- The minimum spacing is "
- The minimum edge dimension is "
- The minimum plate thickness is "

Finally, compare 1" bolts — Grade 36 and then Grade 50 plate

- The minimum spacing is "
- The minimum edge dimension is "
- The minimum Grade 36 plate thickness is "
- The minimum Grade 50 plate thickness is "

Of course, it is simple to specify the plate thickness to achieve 100% capacity. However, the beam web may still limit the bolt capacity as in the following example.

For a Grade 992 W12x30 beam, the web thickness is 0.26″.

- At a minimum spacing of "
- At a minimum edge dimension of "
- The calculated shear capacity is only 43% of the 17.9 kip capacity of a " A325 bolt

The post AISC Bolt Shear Capacity — Minimum Dimensions Feb 2024 appeared first on Hoitsma Blog.

]]>A Serious Article

Brian Potter

January 18 2024

"For most of the 20th century, the US was unrivaled in its machine tool technology, and as late as the early 1980s it was the largest machine tool producer in the world. But almost overnight, the industry collapsed: annual machine tool shipments declined by more than 50% in 2 years, hundreds of machine tool companies went out of business, and the US slipped from the largest producer in the world to the 4th or 5th (depending on the year), roughly where it remains today.

The post What Happened to the US Machine Tool Industry? Jan 2024 appeared first on Hoitsma Blog.

]]>**Suitable as bookmarks**

**Note**

This method, as shown, is applicable and very easy for dates in the 1900s and the 2000s.

2024 – (4 x 28) | 1912 |

2024 – (3 x 28) | 1940 |

2024 – (2 x 28) | 1968 |

2024 – (1 x 28) | 1996 |

2024 + (1 x 28) | 2052 |

2024 + (2 x 28) | 2080 |

2024 + (3 x 28) | 2108 |

**Citation**

Unfortunately, I cannot remember where I found this **specific method (using 2024 as a basis)**. If anyone knows the source of this **specific method**, please let me know. Thanks.

**Excellent Articles**

**As Simple As It Gets**

The post What is the Day of the Week? Jan 2024 appeared first on Hoitsma Blog.

]]>Two Examples using PyXLL and Python dictionary references

**Example 1 — On the Fly Dictionary**

Thanks to the generous guidance of Tony Roberts, I programmed a simple example using a dictionary.

I created two PyXLL functions:

- the first function is called from Excel; using PyXLL, it creates an ad hoc dictionary from cells in Excel

Reference: PyXLL dictionary types - the second function is called from Excel; it provides access to the newly created dictionary

Several such dictionaries can be easily created.

**Details**

The user enters keys and values in an Excel range. In my example, the entries are in the range **G7:H10**. The keys are in Column G; the values are in Column H.

Keys |
Values |

a | apple |

b | banana |

c | carrot |

d | 256 |

In cells **B7:B10**, I enter arbitrary key values.

In cell **C7**, I enter the formula =get_adhoc_dict(B7). I copy the formula to **C8:C10 **. The dictionary values are retrieved in cells **C7:C10**.

Please notice that for each formula, I display the formula text in the cell adjacent (to the right). A red font indicates a user entry; a blue font indicates a formula entry.

**Excel spreadsheet**

**With precedent arrows**

**Code**

I offer the Python code and the PyXLL functions.

from pyxll import xl_app, xl_func #-------------------------------------- @xl_func("dict: object") def make_adhoc_dict(x): """ twocol: two column range (col 1: key; col 2: val) key and value types are optional and default to var if not specified """ return x @xl_func("object, var: var") def get_adhoc_dict(dictobject, xkey): return dictobject[xkey]

Using PyXLL, I programmed a * custom example* using a PyXLL object.

**Background**

Several years ago, I created a new class, a dictionary containing all the AISC structural shapes. For each of the (over 2000) AISC shapes, I have 89 attributes. The attributes are the structural properties associated with each shape.

**Example**

The ‘magic’ in this example is that the dictionary value reference will be kept in a single Excel cell. This is our object reference.

Using the first function, the reference is established. The second function retrieves attributes from the object reference.

**Details**

**AISC Shapes (excerpt)**

**AISC Shape Attributes (excerpt)**

Then I create two PyXLL functions:

- the first function is called from Excel; it creates an object reference to my shape
- the second function is called from Excel; it provides access to the shape attributes

Excel cell **C3** is named ‘my_shape’

Excel cell **C15 **is named ‘my_2nd_shape’

In cell **B3**, I enter an arbitrary AISC shape. In cell **C3**, I enter the formula =get_object_shape(**B3**).

In cell **B15**, I enter an arbitrary AISC attribute. In cell **C15**, I enter the formula =get_object_shape_prop(my_shape, **B15**);. The attribute value is retrieved in cell **G8**. I then copy down the formulas from **G8:H8** down to **G9:H12**.

The pattern is repeated for my other object reference.

Please notice that for each formula, I display the formula text in the cell adjacent (to the right). A red font indicates a user entry; a blue font indicates a formula entry.

**Excel spreadsheet**

**With precedent arrows**

**Code**

Again, I offer the Python code and the PyXLL functions.

from pyxll import xl_app, xl_func #-------------------------------------- @xl_func("str x: object") def get_object_shape(x): # V1415S is the alias of an imported module # 'ga_static_dict' is my dictionary of AISC shapes gasd15 = getattr(V1415S, 'ga_static_dict') return gasd15[x] @xl_func("object my_obj, str p: var") def get_object_shape_prop(my_obj, p): return getattr(my_obj, p.upper())

Of course, as Raymond Hettinger says, “there must be a better way”

And here it is, in a post from 2017.

The post Excel — Dictionary References with PyXLL Jan 2024 appeared first on Hoitsma Blog.

]]>Hand calculate truss forces

See original hand calculation PDF

I decided to check (verify) the calculation set using the same approach as the original engineer — except using Python, Sympy, and Jupyter — and then compare those results with RISA 3D.

I followed the same method as the original engineer, used the same engineering parameters. There is one difference: the original engineer worked by hand, I worked using Python, Sympy, and Jupyter.

Notice that this structure is not a true * determinate* truss. Had there been a diagonal in the center bay, it would have been a truss). Therefore, our structure is

For further insight into * determinacy* in structural analysis, here are two links:

The method used is from a theorem by Alberto Castigliano published in 1873 (his dissertation!):

The redundant reaction components of a statically indeterminate structure are such as to make the internal work (strain energy) a minimum.

References for Castigliano’s work:

I notice that the original engineer obtained a value of * 1.549 kips axial load* in each of the two posts whereas I calculated a value of

According to RISA, the axial force in each of the two posts was * 1.0723 kips*. RISA uses more exact values for the member moments of inertia and areas. My answer was 1.0723 kips when I used the more exact member properties. In the RISA model, I turned off the following:

- the shear deformation option
- the P-Delta option
- the AISC code stiffness reduction, since we are only seeking the model loads rather than a code capacity

My assessment is that the original engineer set up the virtual work problem perfectly (Page 1) including all the calculus equations (Page 2) but then made an arithmetical error or errors getting to the final answer.

See my Jupyter notebook (reads best on a wide screen)

This post illustrates a few points:

- hand methods are quite powerful (even in 2023)
- a computer algebra system (CAS) can help eliminate arithmetic errors
- hand methods (or CAS) can provide verification of RISA models
- hand methods (or CAS) can provide closed-form solutions
- hand methods can provide formulaic insight into the various effects of member geometry and member stiffness

My Jupyter notebook with all-variable integrals

The post Hand Calculated Truss vs RISA Dec 2023 appeared first on Hoitsma Blog.

]]>Mesmerizing

**Wiki Excerpts**

Kolam, also known as Muggu, and Rangoli is a form of traditional decorative art that is drawn by using rice flour as per age-old conventions.

Kolams or muggulu are thought to bring prosperity to homes. In millions of households in Tamil Nadu, Telangana, and Andhra Pradesh, women draw kolams in front of their home entrance every day at the break of dawn.

https://en.wikipedia.org/wiki/Kolam

https://en.wikipedia.org/wiki/Rangoli#/media/File:Rangoli_chennai.jpg

The post Kolam Muggu Rangoli Dec 2023 appeared first on Hoitsma Blog.

]]>Two presentations by Stephen Wolfram

November 10, 2021

The Entangled Limit of Everything

The Entangled Limit of Everything

Read it; I dare you.

https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/

September 29, 2023

An Unexpected Correspondence

An Unexpected Correspondence

A picture ≥ 1000 words.

https://writings.stephenwolfram.com/2023/09/expression-evaluation-and-fundamental-physics/

Specifically, the discussion of the rulial case:

The post Wolfram — Writings Dec 2023 appeared first on Hoitsma Blog.

]]>Just two out of so many wonderful lectures

https://www.feynmanlectures.caltech.edu/I_03.html

Given October 3, 1961

Lecture #3

Lecture #3

Exciting stuff

**The Value of Science**

https://khoitsmahq.firstcloudit.com/images/feynman.pdf

Given at the 1955 autumn meeting of the National Academy of Sciences

A sober lecture

**Excerpts**

To every man is given the key to the gates of heaven; the same key opens the gates of hell.

…

When we read about this in the newspaper, it says “Scientists say this discovery may have importance in the search for a cure for cancer.” The paper is only interested in the use of the idea, not the idea itself. Hardly anyone can understand the importance of an idea, it is so remarkable. Except that, possibly, some children catch on. And when a child catches on to an idea like that, we have a scientist. It is too late for them to get the spirit when they are in our universities, so we must attempt to explain these ideas to children.

**End of Excerpts**

https://www.feynmanlectures.caltech.edu/

A treasure trove

**Bonus — Four Lectures**

https://www.feynmanlectures.caltech.edu/TIPS_01.html

All of these are so well done

https://www.feynmanlectures.caltech.edu/TIPS_02.html

https://www.feynmanlectures.caltech.edu/TIPS_03.html

“Remember: Whenever you’re stuck in a mathematical analysis, you can always do it by arithmetic!”

https://www.feynmanlectures.caltech.edu/TIPS_04.html

The post Feynman — The Relation of Physics to Other Sciences Dec 2023 appeared first on Hoitsma Blog.

]]>Often while working, an arithmetical answer is needed — exact is sometimes required, approximate is often acceptable — maybe the basis of a decision or a path forward is based on a few quick calculations, with more rigorous calculations to follow

**Let’s illustrate with examples from two groups**

Question: What is ?

Try it by yourself this time

Solution:

Try it by yourself this time

Remember the binomial theorem or Pascal’s Triangle. Let’s go back a few years and refresh.

Question: What is ?

Solution:

And ?

Solution:

Question: What is ?

Now dropping the last two terms, we have

Solution:

Now dropping the last two terms, we have

The exact answer is

Therefore, by using only three terms we have an error of less than

Therefore, by using only three terms we have an error of less than

Now let’s consider a few squares.

Question: What is ?

Recall that

Solution:

Question: What is ?

Recall that

Solution:

Question: What is ?

Again

Solution:

Now let’s consider common temperature conversions.

Recall

Or

Easier if approached using

Which is simply less plus

Or

Easier if approached using

Which is simply less plus

Question: What is the Fahrenheit equivalent of ?

Say less plus

Say plus

Say plus

Therefore,

Say plus

Say plus

Therefore,

Recall

Or

Easier if approached using

So say times half plus times a tenth of a half and so forth

Or

Easier if approached using

So say times half plus times a tenth of a half and so forth

Question: What is the Centigrade equivalent of ?

Say

Say half of

Say

Therefore, .

Say half of

Say

Therefore, .

Question: What is the Centigrade equivalent of ?

Say

Say half of with a remainder of

Say

Say half of with a remainder of

Say

The extra is to account for the remainder of 1

Therefore, .

Question: What is the Centigrade equivalent of ?

Say

Say half of

Say

Therefore, .

Say half of

Say

Therefore, .

How to use the divisors of 1, of 10, and of 100

2, 5

To multiply by 5, we can divide by 2 and vice versa, whichever is easier!

Just say 184 over 2 times 10; therefore, .

Just say 121 times 5; therefore, .

Just say 3243 times 2 over 10; therefore, .

Just say 4585 over 5 times 10; therefore, .

Just say 1236 times 2; therefore, .

2, 50

5, 20

4

To multiply by 25, we can divide by 4 if it’s easier that way

What is ?

Just say 160 over 4 times 100;

therefore, .

therefore, .

What is ?

Just say 6 times 4;

therefore, .

therefore, .

8

3

6

7

9

12

Just say 47 over 12; therefore, ~

Could say 47 over 12 less say ~;

therefore, ~.

The exact value is Could say 47 over 12 less say ~;

therefore, ~.

15

Just say 630 over 15 times 10; therefore, times ; therefore, .

Click for a couple three quick examples using aliquot parts

The post Engineering Math Nov 2023 appeared first on Hoitsma Blog.

]]>