Life in Outer Space – A Mathematical Approach

Milky Way Galaxy
Photo by Arnaud Mariat on Unsplash

Is There Really Intelligent Life Out There?

One of our previous articles discussed the minerals of Star Trek, giving rise to the hope that there is extraterrestrial life out there, but the real discussion about ET’s existence is a loaded subject. 

For this article, we are going to focus on what the mathematical formulas tell us. The ones developed by astrophysicists; in other words, what are the odds that there really is intelligent life on other planets?

As difficult it is to comprehend that the sun fuses hydrogen and helium resulting in the power of 100 billion atomic bombs every time second, we need to go even further and try to comprehend the immense size of our universe.

It is estimated that there is an average of 1 – 2 billion stars in any recorded galaxy and there are over 2 trillion galaxies in the universe. If 10% of each galaxy contains a solar system, that is, it contains a star with planets revolving around it, then we can estimate that each galaxy has between 100 – 200 million solar systems. If 1% of the stars in each solar system has a planet just distant enough from their sun where life could evolve, we could have 1 – 2 million possible planets that could contain life. And if 1% of these planets have the right ‘ingredients’ to build intelligent life. then there is the possibility that there exist 10,000 stars that could have planets with intelligent life in each galaxy.

Cutting the odds even further, let’s take 10% of this result, which would equate to the possibility of 1,000 stars with intelligent life in each galaxy.

That would mean that there could exist 1,000 x 100,000,000,000,000 (galaxies) = 1,000,000,000,000,000,000 (1 Quadrillion) planets with intelligent life. How many is that? Take a look at this numerical comparison.

If we use the estimate of 200,000,000 galaxies in the universe, well, that would mean ET lives in over 2 quadrillion planets in our universe.

Don’t even try to comprehend how many fusion reactions occur in the universe every second. Fuhgeddaboudit!

What About the Scientific Formulas?

The above calculations were based on a general assumption, but have the experts really gave this serious thought? Of course!

American astronomer and astrophysicist Dr. Frank Drake developed a formula that he presented at a meeting in Virginia in 1961 and it is called the Drake Equation, which calculates the possibilities of life on other worlds within our own Milky Way galaxy.

Drake Equation
Nasa Photo

We won’t go into the particulars, but in a general sense, it is based on calculating our assumptions above but uses trigonometry to formulate a much more explicit and precise determination of ET’s existence. For you science and math connoisseurs, feel free to give it a shot!

Just maybe Men in Black had it right!


What is Concrete?

What is Concrete?

Concrete Blocks
Photo by uve sanchez on Unsplash

Ever notice that just about every building has a concrete foundation? (show pic). There is a very good reason for this and it is not about aesthetics. Concrete has enormous compressive strength, meaning that it is an excellent material for holding up the weight that is above it. 

Concrete is not just used for foundations, but also for columns, beams. slabs and just about anything where there is a load-bearing issue. Load bearing meaning an element that supports the weight above it. The amount of weight that the load-bearing element would support would depend upon how many concrete columns (or other concrete supporting materials) are available to support the whole load.

For example, a 30-story building has 10 supporting columns on the ground. That would mean that the weight is evenly distributed across each of the 10 columns or mathematically speaking, each concrete column would support 0.333 (10/30) of the load (building).

Another probably more identifiable example is the load-bearing walls in a house. If you live in a house, you have probably come aware of where your load-bearing walls are. These are the walls that actually hold up the house; however, for frame houses, concrete is not the usual load-bearing material, but heavy wood or steel instead. 

In short, concrete is an excellent source for withstanding the heavy forces that are above it. And did you know that concrete also gains more strength as it ages? With that said, let’s take a look at just what concrete is actually made of.

What is Concrete Made Out of?

Concrete is a mixture of air, water, sand and gravel and the percentages of these elements are usually 20% air and water, 30% sand called fine aggregates and 40% gravel, with 10% being the cement; that is, 10% being the ‘glue’ that keeps all those other materials together. Remember, from our article on cement, it is just the binding material for the assembly of concrete. When the cement is mixed with water, it is called paste

This proportion is called the 10-20-30-40 Rule; however, the exact percentages of the materials can vary depending on the combination of the concrete mixture, including the type of cement and other factors that we will explain in this article.

How are the Proportion of Materials that Form Concrete Determined?

So we know that concrete is a mixture of paste and aggregates and sometimes rocks. The paste coats each of the aggregates and as it hardens (the process is called hydration), concrete is born until it becomes a rock-solid mass, capable of withstanding a load much heavier than itself, but if the proportion of water and paste is not correct, this rock-solid mass can deteriorate causing unwanted and potentially dangerous consequences.

The trick is to carefully proportion the mix of the ingredients and much of it depends on the ratio of water to cement and this ratio is calculated by the weight of the water divided by the weight of the cement. A low water-content ratio yields high-quality concrete, so it is best to lower the ratio as much as possible without sacrificing the integrity of the concrete.

If the ratio results where there is too much water in the mixture, the aggregates become thinned out, resulting in weakening the concrete and we can figure out what that would mean.

Conversely, If there is not enough water in the mix, the water will evaporate too fast, comprising the integrity of the concrete and resulting in it being weak as well.

What is the Strongest Concrete Mixture Ratio?

1:3:5 which is cement and aggregates (in this case, the aggregate is broken into sand (3) and gravel (5) and this is considered the ratio that would create the strongest concrete.

How Much Time is Allocated Before the Finished Concrete is Used at the Construction Site?

There is a limit to how long the concrete can be poured after it is mixed. In the US, the limit is 60 minutes from the time the water mixes with the cement to the time of delivery to the construction site. 

A safe time frame is up to 90 minutes, then the integrity of the concrete will start to deteriorate. That is why we see concrete mixers right at the construction site as no time is lost between the mixture and the pouring.

What About Reinforced Concrete?

As the name applies, when steel (usually using steel bars, called rebars) is placed inside the slab where the concrete is going to be poured, it reinforces the strength of the concrete.

How Does it Reinforce the Concrete?

We have been discussing compression strength; that is, how strong the material is when a heavy load is placed on it, but we haven’t discussed tensile strength, which is the opposite of compression.

Tensil strength represents the strength a material can endure when a force tries to pull on it. The reason why compression is so important when using concrete is that that is its main purpose – to hold up heavy loads, but concrete does have a limit on how much pull can be leveled on it and there are situations where the tensile strength of concrete is put to the test. Weather being one factor, but there are more.

Enter Steel

Reinforced Steel Slab
A construction worker working on a reinforced steel slap where the concrete will be poured

By integrating the rebars inside the concrete, the concern about stretching the concrete is greatly minimized. The combination of concrete and its accompanying reinforcing steel bars successfully manages these situations, because of steel’s high tensile strength; hence, you have a perfect storm of compressive and tensile strength in reinforced concrete (RC).

What Happens if the Reinforcing Steel is Not Inside the Concrete?

Cracking of the concrete surfaces can occur, subsequently causing aesthetic issues, but if the tensile yield is really great, (e.g. a strong pull on the concrete) the situation can become unsafe, so without the steel rods to compensate for this pull, you will find cracks in the concrete or worse.


Concrete is a mixture of sand, water, aggregates and cement. The amount of any of these elements will determine the strength of the concrete. Timing also plays a role as the concrete must be readily mixed within 90 minutes max, but 60 minutes is the usual requirement before being poured into its foundation or another element such as a column or slab.

By placing steel bars which is a mesh of steel wires (rebar) inside the concrete, the tension issue is resolved by aiding the concrete under tension.

So the next time you are walking in a building, especially a large structure such as a skyscraper, give thanks to the materials that allow you there, as well as the people who created allowed it to happen!


How Cement is Made

What is Cement?

Solider pouring the fine powdery cementBefore we explain the cement process, let’s make sure that you understand that cement is not concrete.

With that said, you can think of cement as the ‘glue’ that cements other materials together, usually sand and gravel to create items such as concrete, but cement is rarely used on its own. 

 According to Wikipedia, cement sets, hardens and adheres to other materials  to bind them together.” In simple terms, cement is the centerpiece of what keeps concrete together. 

What Materials are Cement Made of? 

The sand and gravel are called aggregate, and it is these materials that are bound together but remember, cement is not the material, it is just the glue. So what makes up cement? 

The ingredients are mainly limestone and clay, which are extracted from quarries from around the world. Of course, the process of making cement is not that simple. The limestone is heated with clay to 2,640 °F in a kiln (an insulated chamber). This process is called calcination, which liberates molecules of carbon dioxide from the calcium carbonate (the main ingredient of limestone) to form calcium oxide, commonly referred to as quicklime

It is here where the quicklime chemically combines with the other materials to make a hard substance, called ‘clinker‘. Gypsum is then added to make Portland cement, the most popular type of cement used, which is referred to in the industry as OPC. 

How does the Limestone Mixture Process Work?

The limestone rock is crushed in a machine appropriately called a crusher which reduces the limestone to a size of about six inches maximum. It is then fed into the second crusher where it is further reduced to under three inches. The mix is conveyed and then sent to a raw mill bin to be ground down even further.  

In these bins are two chambers. One that dries the limestone and clay mix and the other that grinds it via hot gasses. Then, once all dry, it is moved to the grinding chamber called a ball mill.  Here there is a cylinder that contains steel balls and rotates which causes the balls to fall back into the cylinder and onto the limestone mix; hence, grinders. 4 to 20 revolutions per minute is the general rotation of the cylinder, which is dependent upon the diameter of the ball mill.

A Newcome Engine

What’s left when the grinding process is done is a product of fine and coarse material. The coarse material is useless in that state and is called reject where it is returned back to the ball mill for additional grinding. A machine called a separator does this part. 

Having the limestone and clay grounded down to a fine powder is still not enough to complete the cement process. The mixture must then enter a device called a cyclone which is used to separate the fine grounded material from existing gases that still exist in it.

Then, the hot gas and fine materials enter a multistage “cyclone”. This is to separate the fine ground materials from the gases.

The result – a clean, fine powdery material and is renamed kiln feed. 

Next, the feed is heated via a process called sintering, which is when the chemical bonds of the material are broken down using heat and once complete, a new substance is formed called clinker.

Clinker nodules for the production of cement
Clinker nodules produced by sintering at 1450 °C. This is the intermediate process for the production of cement

The clinker is initially very hot and contains small, dark gray nodules from 1mm to 25mm in size where it is placed into a grate cooler for cooling from approximately 2550 °F to approximately 240 °F via the use of cooling fans.

And voila! You have cement!

Final Note

Other elements are added to the clinker depending upon what the cement is going to be used for. In the case of Portland cement, gypsum is the additive.

And you thought that making cement was just adding powder and water. We hope you gained some good knowledge as to how cement is actually created.




How Buildings are Constructed Along Earthquake Fault Lines

Transamerica Pyramid San Francisco
Earthquake resistant Transamerica Pyramid, San Francisco. Photo Wikimedia CC

One of the first structures built to withstand an earthquake was the Transamerica Pyramid, also called the Transamerica Tower. In this seismically active region, no engineering was spared to keep the building safe from earthquake tremors.

Located on 600 Montgomery Street, it rises 853 feet and 48 floors and was the eighth tallest building in the world in 1972. On the highest floor, 48, there is a conference room that has unobstructed 360-degree views of the San Francisco Bay area.

The building has a wide base that narrows upwards, much like the churches and buildings of antiquity, which is designed to give the structures their stability. No doubt this is an optimum method for buildings that reside along earthquake fault lines. From an environmental perspective, the pyramid design (hence the name), allows natural light to filter down to the streets below.

Looking to limit the degree by which the structure would twist and shake during an earthquake, engineers used a unique truss system with built-in steel, reinforced concrete, precast quartz aggregate and glass. It has two angular setbacks working their way up to the top of the tower and a 212-foot spire. There are two angular concrete structures on the east and west sides that protrude from the 29th floor rising upwards called wings. The wings are part of the structural engineering that went in to keep the building sturdy during an earthquake, but they also have a function. The eastern wing serves as an elevator and the western wing includes a staircase.

To reinforce the building even more, there is a truss system on the ground and lower floors which are designed to support both vertical and horizontal stresses. Truss designs are cross beams engineered to perfectly distribute the weight of a structure in order to withstand tension (pulling) and compression (pulling) forces.

Modern building with external truss system
Buildings with external truss systems are able to manage torsional (twisting) forces generated by seismic events. Photo by Ricardo Gomez Angel on Unsplash

Under the truss, beams are X beams over the ground floor, designed to brace the building against any type of torque movement.

This torque and stress reinforcement was tested in 1989 during the .71 magnitude Loma Prieta earthquake. The building successfully withstood the quake with no damage and no injuries.


In addition to above-ground stress reinforcement, there is an additional basement from earthquake tremors, consisting of a 9-foot deep concrete mat foundation, which lies on top of a steel and concrete block that goes 52 feet underground. This foundation contains 16,000 cubic yards of reinforced concrete, including over 300 miles of steel reinforcing rods. This concrete assists with the additional support of Compressive stress and tensile stress.

The Pyramid is a self-contained structure, which has its own 1.1-megawatt power system. Construction began in the fall of 1969 with the first tenant moving in in 1972 and is still standing gracefully today as a monument to earthquake building construction.


The 2 Methods to Building a Subway

Subway tunnel construction in NYC
Subway tunnel construction in NYC  (Photo: wirestock –

For those who love big cities (and even smaller ones), there’s no doubt you have ridden on one of their mass transit lines. With that said, have you ever wondered about the amount of engineering that has gone into building one? Well, here we will give you some basic information as to how they are constructed.

There are two basic methods to subway construction: “cut and cover” and the other is called “deep bore.”  Cut and cover refers to the complete opening of the street, down to where the subway would be built and deep bore refers to the burrowing strategy previously discussed in our Tunnel Boring article.

To determine which method is going to be used, an engineering and environmental review is necessary, which includes logistics, underground water determination, earth material, demographics and of course, costs, not to mention the bureaucracy of working with the different city agencies to determine where all the utility lines, water pipes and potential other tunnels are located. 

This bureaucracy alone could take months or even years, And if any of these factors become obstacles, then additional planning would be required. The bottom line is that this whole procedure is a great undertaking and can get very complex. 

So with this introduction, let’s delve into describing the engineering process by which each of these methods would be used.

Cut and Cover Method of Building a Subway

Tunnel cut and cover method of construction of the Paris Metro
Tunnel cut and cover method of construction of the Paris Metro – Wikipedia Public Domain

This method is found in the building of some of the older subway systems, such as the Paris Metro, London Underground and the NYC subway. With this method, the pavement of the street is completely removed and then a hole is dug down into the ground. 

“Cut and cover” is considerably cheaper than the “deep bore” method; however, the dig must parallel the street, so there is no room for more sophisticated planning, like curved tracks that fork off to some desired locations, unless the street above does the same.

Another undesirable factor is that “cut and cover” results in large holes in the street significantly causing traffic nightmares, as well as major inconveniences for store owners along the route.

Deep Bore Method 

The boring machine is a sophisticated and expensive apparatus that cuts through the underground dit by using circular spinning blades. The advantage this has over “cut and cover” is that they do not have to follow the street grid above, allowing much greater flexibility in the design of the subway lines, as well as not have to dig big holes along the route. The boring method is slow, but efficient and cuts through the earth at a rate of about fifty feet per day

The disadvantages are that the costs are significantly higher than cut and cover, where $150 million would be a medium price. 

How the Subway Construction Method Is Decided

As mentioned, there are so many factors to consider when building a subway line, but the number of subway lines and the cost factors involved would be the major considerations.

For example: After extensive analysis of which method would be better to construct the Second Ave Subway in Manhattan, it was decided that the TBM would be more efficient, based upon the fact that cut and cover would cause so much economical damage, the boring method would be more practical, even though it is more expensive.

Preparation for TBM cutting head to be lowered into a tunnel
Cutting Head of a boring machine being lowered into the hole where a tunnel is to be constructed. Photo by david carballar on Unsplash

Just lowering this giant machine into the tunnel is a major task, not to mention expense, but it is worth it in the case of big-city construction.

Another major consideration was the amount of interruption and financial damage the cut and cover method would have caused, especially on a congested and commercial road like Second Ave. where the upper east side and midtown Manhattan would be commercially interrupted.

Considering how often there would have been complaints, especially in this time period, where community demonstrations are the norm, more and more TBM usage is becoming the preferred method, so as not to disturb life above ground. However, cut and cover construction may still be considered if the soil conditions are not up to standard.

Building the Second Ave Subway NYC
TBM in action during the building of New York’s Second Ave Subway (Google CC Flicker)

An example of how the political consequences of cut and cover road disruptions can escalate, take a look at Vancouver B.C.’s recently opened Canada Line. A lawsuit was taken against the city of Vancouver and the plaintiff, a retailer with a store along the subway route where won C$600,000 after cut and cover caused major financial hardship. Following that lawsuit, an additional 41 plaintiffs have taken legal action to recover financial damages. 

What the Future Holds

We are now in the 21st Century and with technology streaming at a rocket pace (e.g. artificial intelligence, at home video conferencing, sending a man to Mars) it will only be time before new engineering technologies will lead to faster, lighter and much less expensive boring machines. Then if you think some cities have excellent transportation facilities now, wait till these new machines come along and open the door to even more elaborate and reduced financial expense.  



Understanding the Geology of Silver

10 Gram Silver Bar
10 Gram Silver Bar

Silver – Overview 

This soft, white, precious metal is valued for its beauty and industrial uses. It has a history that goes back as far as 4,000 B.C. Around the same time, techniques to refine silver and separate it from other metals were identified and practiced. As research on natural elements progressed, silver got its chemical name and secured its position in the periodic table in group 11 and period 5. For our science enthusiasts, this malleable metal has the following element properties: 

    • Atomic Number – 47
    • Atomic Weight – 107.8
    • Melting Point – 1,861.4oF
    • Boiling Point – 4,014oF
    • Specific Gravity – 10.5
    • Luster – Metallic
    • Mohs Hardness – 2.5 to 3 

Because of its rarity and high industrial demand, silver is considered a precious metal with a high economic value. Its physical properties make it the best possible metal for various uses in a wide variety of industries. 

For starters, it has electrical and thermal conductance that is higher than any other metal, which makes it valuable in the electronic industry.  Silver is also sort after because of its exceptional ability to convert ethylene into its oxide, a prerequisite of many organic compounds. However, it is the least reactive of the transition elements.

Moreover, it has better reflectivity at most temperatures. Finally, its color and attractive finish make it a desirable choice for coins, tableware, jewelry and many other objects.

Given its uses and properties, silver is often the material of choice. However, unlike other precious metals, the value of silver is often not reflected in the price, which makes it one of the most underrated precious metals.

Let’s take a closer look at how silver is found in nature.  

The Geology of Silver 

The precious metal occurs in nature as one of the four following forms.

  • as a natural element; 
  • as an essential component of silver minerals; 
  • as an alloy with other metals; and 
  • as a trace element in the ores of other metals. 

Below we intend to understand the geology of the precious metal better.

Silver as a Natural Element 

Silver rarely occurs as a natural element. Instead, it is often found with other metals, including gold, copper, quartz and sulfides and other metals’ arsenides. In placer deposits, silver is rarely discovered in significant amounts. Because it does not oxidize readily, silver can also be found above the ores of other metals in its natural state. However, the precious metal reacts with hydrogen sulfide that results in a discolored surface, including silver sulfide, also known as acanthite. Researchers have found many specimens as a natural element that have been exposed and reacted with hydrogen, and have an acanthite coating.

Silver in this form is often associated with hydrothermal activity. In areas of abundance in this activity, silver can be found as cavity fillings. Some of these deposits are rich enough to support mining. However, mining for silver alone is often not feasible. Therefore, the economic viability of silver extraction depends upon the presence of other valuable minerals. For extraction of such deposits, an underground operation is undertaken that follows the veins and cavities where silver in its natural state is found. 

As an Essential Component of Silver Minerals

Close up of Silver CoinsThere is a surprisingly high number of minerals that contain silver as an essential component. There are over 35 different distinct silver minerals which include but are not limited to the following. 

  • Acanthite, 
  • Berryite, 
  • Chlorargyrite, 
  • Dyscrasite,
  • Empressite, 
  • Fettelite, 
  • Petzite, 
  • Samsonite

Each of the silver minerals is distinct and rare, however, a few silver minerals exist in quantities that warrant mining. Silver minerals can be found as silicates, sulfides, iodates, carbonates, oxides, nitrates and bromates. 

Alloys and Amalgams of Silver 

If you take a closer look at the placer deposits of gold, you will find gold alloyed with small quantities of silver. When the ratio between gold and silver reaches at least 20% silver, the alloy is called “electrum” which is a combination of silver and gold. When gold is refined and purified, that leads to the production of a significant amount of silver. Interestingly enough,  most of the silver available on the market today is a byproduct of gold extraction and purification.

The metal can also be found as a natural alloy of mercury, which is found in the oxidation zones of silver deposits. This amalgam of silver is also associated with cinnabar, which is a toxic mercury sulfide mineral. 

As a Trace Element in the Ores of Other Metals

The other most common source of silver is its occurrence as a trace element in the ores of other metals. It is often found along with other commonly extracted metals, including copper, lead and zinc and can be found as an inclusion within the ore. Moreover, it can be found as a substituted metal ion within the ore’s atomic structure. However, there is a possibility that the value of silver may exceed the value of the primary metal within the ore.

Silver – Extraction and Production Around the World 

Silver is found all around the world. Over 50% of its production comes from North, Central and South America. Other contributors of silver outside America include Russia, China and Australia. 

Silver deposits are usually associated with magmatic and hydrothermal activity. Major mineral deposits are therefore found in these regions. The association between geothermal activity and silver deposits is more pronounced in the Americas, where the silver production follows the Andes Mountain Range. In other parts of the world, the production of silver is related to igneous activity regardless of its geologic age, but a different trend has been observed in Europe, where silver production is associated with historic volcanic activity. 


Silver is a precious metal with various industrial and commercial uses. While its worth is often not reflected in its economic value, silver still remains a rare, precious metal, given how it is found in nature. 

How Tunnel Boring Machines Work

NYC subway tunnel with tracks crossing
NYC Subway Tunnel. Note the concrete slabs, called rings on the sides and ceiling of the tunnel Photo by wirestock –

Did you ever wonder how a tunnel is created?  Well, you’ve come to the right place.

Human ingenuity has taken us from the industrial revolution to space exploration, but it has also taken us underground, from the giant Bagger 293 bucket wheel excavator for mining to machines that crush through the dirt to make tunnels deep below the surface.

A Little Tunnel History

In the earlier days, boring through the underground required many hours of tedious labor. It was not just the dig that was time-consuming but buttressing the area around the tunnel so that it stayed safe was also tedious.

Men would create concrete rings and secure them along the top of the tunnel and alongside the walls.  This would ensure that the tunnel didn’t weaken and collapse.

Assembling concrete rings were previously done with manual labor

The process of securing the tunnel by hand was the normal way of doing things back in the day, but now, all that hard, unhealthy labor is a thing of the past. Why? Enter the tunnel boring machine (TBM).

The Tunnel Boring Machine

Tunnel Boring Machine

Power Saw
Photo by Greyson Joralemon on Unsplash

If there was ever a device that one would call a machine, the TBM would be just that. Large, noisy but effective, it is used to cut through soil and rock much like a power saw is used on wood. As the saw’s steel blade spins, it cuts right through the wood, which is similar to the job of the boring machine, only larger. Much larger!

How Does the TBM Work?

The machine consists of three major parts (actually, a lot more, but we’ll keep it simple so that we don’t bore (pun intended) you with all the intricate details). 

The Three Parts are: 

  • Cutter-head (front)
  • Tunnel shield (middle)
  • Trailing gear (rear)

Of course, each of these sections is made up of smaller parts and together they comprise the boring machine.

The Cutting Head

Preparation for TBM cutting head to be lowered into a tunnel
Preparation for TBM cutting head to be lowered into a tunnel. Photo by david carballar on Unsplash

We spoke about the saw, but what does this saw have that cuts the wood so precisely? It is a circular piece of steel with cutting blades.

For the TBM, they are called disc cutters and are integrated onto the edges of a round piece of steel. For the TBM, the cutting head is located at the very front of the machine. 

As the boring machine’s cutter-head rotates, it breaks through the rock and/or soil at a rate of 2.7 revolutions per minute and at a pace of about 50 feet per day. 

The machine looks like a giant worm, expanding about 272 feet in length. It is this long because after the soil is extracted, it is sent down long conveyor belts where it is extracted to the surface and carted away.  See these videos below, which provide expert explanations about how the Tunnel Boring Machine operates. 

The Tunnel Shield 

A tunneling shield is a cylindrical protective structure that is located just behind the cutting head and is used to shelter the workers from the dangers of falling dirt and debris and/or actual collapse of the tunnel.

The shield is used as a temporary support structure until the tunnel is secured with concrete (see Tunnel Rings below).  The first shield was designed by Marc Isambard Brunel and was rectangular in design with iron scaffolding and consisting of three levels. Then it was later modified into a cylindrical form, which is what is used today.

What are Tunnel Rings?

Tunnel Ring
Tunnel rings. From HerrenknechtAG video above.

The tunneling shield is designed to be used only until the tunnel is safely secured with a more permanent process; as such, prefabricated concrete rings are secured along the roof and sides of the tunnel to stabilize it and turn it into a permanent structure. The process begins when the cutting head stops spinning, synchronized to do so each time a new set of rings are needed to be installed. 

A robot called an erector lifts each ring and sets it in place along the tunnel lining, resulting in a solid cylindrical wall of concrete at the top and along the sidewalls, subsequently maintaining the structural integrity of the tunnel.  

The rings are assembled as segments from above-ground factories. They are transported from the factory to the tunnel location, moved down into the tunnel and onto the boring machine where the erector lifts them and secures them inside the tunnel.

Precast molded lining sections were first patented in 1874 by James Henry Greathead, a mechanical and civil engineer famous for his work on the London Underground. Greathead also improved the tunnel shield from its rectangle form into its current form of cylindrical steel.

This process of cutting through the dirt then stopping so that the rings can be installed alternates every 5–7 feet. The cutting heads spin, evacuating the earth in front of it, then stops and the erector builds the supporting rings and then the cutting head begins to spin again, moving forward at its slow but efficient pace.

Trailing Gear

How Does the Evacuated Dirt and Rock Get Taken Out from Underground?

Tunnel Boring Machine
Tunnel Boring Machine trailer section. Screenshot from video HerrenknechtAG

Enter the trailing mechanisms. They include a conveyor belt that removes the soil that was excavated from the cutter head. As the cutter pulls dirt out, it places it onto a belt conveyor which consists of a machine belt, cross belt and a tunnel belt. The tunnel belt is dynamic, in that it expands as the machine digs forward. The tunnel belt can expand up to 18 miles back to the extraction point where the soil is lifted to the ground.

The first two belts, the machine and cross belt are located at the very front of the TBM and the tunnel belt is the conveyor that moves the debris through the TBM to the area where it is taken out of the tunnel. 


The engineering that goes into the assembly of a tunnel boring machine is quite sophisticated, but fascinating as well. 

In this article, we simplified the process so that it can be easily understandable and we hope you were able to gain a good understanding of how tunnels are created, so the next time you drive through a tunnel or ride through the subway, you can be grateful for the ingenuity and hard work of the people who built it. 


Palladium – A Metal More Precious than Gold


You might have noticed that palladium is listed in the metal’s exchanges along with gold and platinum. That is because it is one of the most precious metals found on Earth. Palladium is a silvery, shiny metal that gives color to white gold. It was discovered in 1803 by an English chemist William Hyde Wollaston. The metal was first isolated following a series of chemical reactions that involved dissolving platinum with several other acids, including hydrochloric acid and nitric acid. However, it was not until 1805 that the researchers working on discovering this precious metal declared it as a newly found element. 

The rare metal, palladium, gets its name from “pallas” which is the third-largest asteroid in the asteroid belt and was discovered in 1802, shortly before the discovery of palladium. 

Chemically, Palladium is one of six elements in the platinum group which consists of the following:

  • Platinum 
  • Rhodium
  • Ruthenium
  • Osmium and 
  • Iridium 

These elements’ chemical structure makes them an excellent catalyst and therefore, they have wide industrial applications. But before we get into its uses, let’s look at a few facts about this rare metal. 

  • Symbol – Pd 
  • Atomic Number – 46
  • Atomic Weight – 106.4
  • Density – 12.02 g/cm3
  • State at Room Temperature – Solid
  • Melting Point – 2,831oF
  • Boiling Point – 5,360 oF
  • # of isotopes – 29
  • The metal is malleable and ductile 
  • Palladium does not react with air

Uses of Palladium 

Let’s look at some of the most common uses of palladium and the industries that use it.


One of the biggest industrial users of palladium in the automotive industry, where the metal is used as a catalytic converter. It works by changing most polluting compounds’ chemical composition so they become less environmentally harmful chemicals. For years, palladium was the top choice for catalysts, but given the significant increase in the price of the metal, automotive manufacturers are starting to look for less pricey alternatives. 

Precious Metals

Another common use of palladium is its use as an investment asset. Given the metal’s rarity, it is one of the highly valued investments and is considered a safe store of value. It is because of its value that the palladium coins and bars have been issued and used as an investment by investors around the world. 


Palladium in White Gold Jewelry
Palladium in White Gold Jewelry Photo: Pexels

While yellow, traditional gold is still preferred for jewelry, white gold is another popular metal. Palladium is used as one of the alloys that give the strength, color and shiny texture to white gold. Its pure form is malleable and soft with a 950 fineness.


Palladium is also used in dental amalgams. The rare metal is combined with small amounts of silver, copper, mercury and tin to help fight against dental corrosion. Moreover, it improves the stability and quality of dental fillings. While palladium is used in minimal quantities, use in dentistry is one of its most critical uses. 

Other Uses 

  • The use in electronic industry 
  • In the manufacturing of professional, concert-grade flutes
  • Photographic printing 
  • Fuel cells, including hydrogen purification 

What Makes Palladium More Valuable than Gold?

Investment Graph
Photo by Markus Winkler on Unsplash

Now that you already know what palladium is and what are some of its common uses, let’s look at the most important question. What makes palladium more valuable than gold?

In 2019, palladium was one of the four most expensive metals along with gold and platinum. But the trend continued long after 2019, and the precious metal is still one of the most expensive metals out there. Here are a few reasons for the increasing price trend. 

The demand for palladium, particularly from the automotive industry, continued to rise as the world became more environmentally friendly and the demand from China particularly rose as pollution is a major concern. 

Moreover, the supply side didn’t respond much to the rising demand. The metal is primarily mined in South Africa and Russia and the producers are not proactive in reacting to the increasing demand. In 2021, the supply fell short of the demand for the 10th year in a row. 

Did You Know?

  • According to the USGS, the U.S. is one of the biggest platinum group importers (which also includes palladium). 
  • Palladium has an incredible power to absorb hydrogen. This rare metal can absorb up to 900 times its volume of hydrogen. Because of this ability, palladium is widely used to purify and store highly volatile hydrogen gas. 
  • Palladium is used for photo printing that makes your photographs look long-lasting. The process uses palladium salts, which become embedded in the photo paper and give it a matte appearance and longevity. 
  • While palladium is relatively inactive, gold jewelry can cause allergic reactions in some people. If you already have a nickel allergy, you are at a higher risk of sensitivity from palladium as well. 
  • Palladium can be somewhat toxic for the human body, but the metal decreases the heart rate and blood pressure. Moreover, it can lead to kidney and liver damage as well as cause damage to the bone marrow. Compounds of palladium such as palladium chloride can be toxic when inhaled, swallowed or absorbed through the skin. 

Latest on the Precious Metal 

The supply of palladium has been falling short for a decade now, but here is some good news about this precious metal. Researchers at Brown University and Rhode Island have found a new way to use the cheaper palladium nanoparticles, which work as a kind of catalytic converter to facilitate water filtration. 

The prototype water filtration system is currently under testing. The objective is to find out if the system can work on a larger scale at a low cost. 

Moreover, research in other areas such as hydrogen storage ability is also underway. Soon other considerations may materialize for palladium. But investing in pallidum to diverse your investment portfolio might not be a bad idea in the long run, especially during this COVID crises. We will just have to wait and see. 

6 Reasons Why She Will Feel Special When You Give Her Amethyst

Photo by Conscious Design on Unsplash

When it comes to expressing love through jewels, the diamond is considered the top choice and colored diamonds are even more in desire; however, rare. But contrary to popular belief, this sparkling gem is not the only gem that signifies true love; amethyst is an equally strong contender to express devotion to one’s paramour. 

The dark and deep, vivaciously violet gemstone is an enchanting mineral that also happens to be the birthstone for February, the month of love. Hence, it only makes sense that lovers present the purple gemstone to one another when professing their love. 

With the world in a state of chaos, primarily due to the pandemic, people are learning to be grateful for the blessings they have, such as a loving partner. This means lovers are searching far and wide to present a thoughtful gift to their beau to appreciate them.

 While a meaningful present could be anything for different people, for most, a stunning piece of crystal tucked in a pendant or ring seems to be the perfect souvenir embodying love. If you also belong to the pro-diamond camp, we have an alluring proposition for you. This time around, choose a different route and go with amethyst to surprise your other half.  Why you ask? Here’s why. 

Amethyst is The Jewel of Gods

If you are one of the mythical lovers, then you can choose amethyst to express your feelings to your beau. Traditionally, and even until now, the pretty purple crystal is believed to be the choice of bishops because of its supposed pure essence. Hence, if you have realized how much your partner means to you and want to relay your heartfelt emotions, go for amethyst and be sure to educate her about the fantastic qualities of amethyst to make your gift all the more meaningful.

Amethyst is Stunning Yet Affordable

Amethyst is as stunning as most other precious stones without even being one, which means you get all the glittery glamour of an exclusive gem without the cost associated with other gemstones. Simply put, the purple sparkler is just as sparkling as any other precious stone but at reasonable prices. 

So now, you can charm your beau with a thoughtful gift without burdening your pocket much. That’s not to say that you shouldn’t splurge once in a while, but with amethyst, you can enjoy class even when the budget is a bit tight!

Amethyst Goes Well With The Colors of Winter 

The chilly season colors the environment in soft, cool pastel shades, creating a romantic ambiance all over. With such a peaceful atmosphere around in the frosty weather, you want to give your partner something that’s not too overpowering while being sufficiently impactful. So, if you plan to present a sparkler to your paramour, you need something that blends in well, like the stunning amethyst.

Amethyst comes in gorgeous shades of purple that do not stand out too much instead complement the winter season. 

Amethyst is the Birthstone of February

Assortment of gemstonesIf you are into astrology, you must know of the birthstones of all the twelve months of the year.

And as it turns out, amethyst is the birthstone of February, which means it’s the perfect present to celebrate true love. 

Saint Valentine’s Ring Had Amethyst

Anyone who knows of Valentine’s Day (which means everyone, because who doesn’t) must have heard of Saint Valentines, the man supposedly responsible for the day of love.

Saint Valentine was a Roman priest in the third century who officiated secret weddings against the authorities. In other words, it can be said that Saint Valentines was a fervent advocate of love, no matter how forbidden. He was later captured and imprisoned at a noble’s home, where he healed his captor’s blind daughter and converted the entire household into Christianity. Consequently, Saint Valentine was tortured and killed on February 14th. But before dying, he wrote a letter to the girl and signed it as your valentine

Whether the story of Saint Valentine is the real narrative behind the day of love or not, one thing is for sure that the Roman Priest was a dedicated supporter of love. So, it’s only natural to give your paramour something that is linked with the legendary Saint Valentines like amethyst.

Legend has it that the Roman Priest also used to wear a ring that had an amethyst with a picture of cupid on top. You don’t need to have a tiny cupid on your purple stone as long as you have the violet stone to celebrate the love between you and your significant other, you are on the right path.  

Amethyst Makes You Wise or So Leonardo Da Vinci Thought

The famous Italian painter and polymath Leonardo Da Vinci, known for his knowledge, talent and vision, admired the alluring amethyst like no other. He believed that amethyst makes a person wise, frees them from evil thoughts and helps them become shrewd when running business affairs.

Whether the Italian savant was right to think so highly of amethyst or just spoke his mind based on experience can never be known. But if you want to follow in the footsteps of a legendary scholar, you should definitely look into buying an amethyst. Even if not for your partner, then buy the violet crystal for yourself to show some self-love because why not?

Amethyst Keeps You Sober

If your partner likes to down liquor a bit much, you should buy them amethyst to keep them from getting intoxicated beyond their capacity. 

The epithet amethyst comes from a Greek word, amethystos, which means remedy against intoxication. Hence, the ancients considered the purple sparkler an aid against drunkenness. The Egyptians would wear amethyst as the gem of protection in amulets around the chest.

Get your better-half an amethyst- also fondly called nature’s tranquilizer, to appease the drinker in them while ensuring they’ll be safe, naturally!

The Bottom Line

Amethyst is not just pretty; it’s also quite sturdy, which is evident from its score on the Mohs scale of hardness. The violet gem has a whopping 7, which may not be as high as the diamond’s 9; it’s still enough to last a lifetime. 

So don’t wait for another second to tell your partner how much they mean to you and how grateful you are to have them in your life with a gorgeous piece of jewelry flaunting a chunky amethyst. 

Want to know more about Amethyst, visit our page here.

What Your Birthstone Says About You?

Purple mineral in a ring setting
Photo Pixaby

What Does Your Birthstone Say About You?

While a birthstone is a great piece of jewelry that may look nice on your finger, it does so much more. They can be a representation of your personality traits. Each birthstone is one-of-a-kind and symbolizes different meanings. Do you want to know how your birthstone describes you? Find out here!

1. January- Garnet

This deep red gemstone resembles a pomegranate seed. It is one-of-a-kind and comes in many different shades, such as orange, purple, green and pink, but is most famous for its dark red hue. 

If you follow the mystifying values of gemstones, the garnet is known to represent confidence and give off positive energy. They are also known to symbolize caring and empathy. And there are more spiritual elements to this gem. It is supposed to provide you with spontaneous personalities and feisty ones at that.

If garnet is your birthstone, you’re likely to take on the challenges that come your way.

2. February- Amethyst

Purple Amethyst in a ring setting
Photo Pixaby

According to early legends, this stone has been long associated with Bacchus, the Roman god of agriculture, wine, and fertility. If you follow mythology, this Roman god is equivalent to the Greek god Dionysus.

This is probably because of its color, which is a deep purple. Amherst itself is known to symbolize peace and tranquility and is a potent gemstone when it comes to religious jewelry; the pope wears an amethyst ring apart from his other jewels.; although, we are sure it’s not because he believes in Bacchus and Dionysus, but maybe it is just because of the gemstone’s beauty.

If amethyst is your birthstone, you are likely to be intelligent, kind, gentle as well as spiritual. You are also probably great at business and are positive and optimistic in nature. Not only are they known to be calm, but have a calming effect on others as well. 

For more information on Amethyst, check out our 2018 article.

3. March- Aquamarine

Aquamarine stone on a ring
Photo by Andy Holmes on Unsplash

Like the ocean? Then this gem is for you! As you can guess, especially by its name, this gorgeous stone is associated with the sea. Its colors vary from greens to blues, the rarest of which is a dark blue.

In some ancient cultures, people believed that this stone could guard sailors and ensure them a safe voyage. 

Those with this birthstone are known to be straightforward, great at communication and inspiring. They are also great at settling disputes in a fair and just manner. We can use them more than ever now!

4. April – Diamond

Sparkling Diamond
Diamond gem with reflection on blue background

What’s the first thing that comes to your mind when you think of diamonds? Its shine? Cut? Hardness? Diamonds, probably the most famous mineral known are also the most sort after stone in the world.

Well, April borns are known to be strong just like the diamond. In addition, they are courageous, positive and pure-hearted; however, they can also be pretty stubborn, after all, they take after the hardiness of their stone. They are also determined and when they make up their mind to do something, nothing can get in the way. Their strong character, paired with their strict moral code makes them extremely loyal and dependable, so if you have a friend born in April, don’t let them go.

And if you are thinking about getting one for yourself or your loved one, don’t forget about the 4 Cs!

5. May – Emerald

An emerald gemstone in organic conditionThis exotic green gem is luxurious in nature. Those born in May are known to be empaths; they are loving, kind and go out of their way to help others.

They give excellent advice and value honest relationships. Many borns are also known to be romantics just as the stone has associations with love and fertility and are also great at matchmaking! Because they are empaths, they can be a little introverted and prefer small gatherings to bigger groups.

6. June – Pearl

Woman wearing pearls
Photo by JJ Jordan on Unsplash

This beautiful gemstone will always be a classic. They come from the water and are radiant. Those born in this month are considered to be fiercely loyal, considerate, patient and thoughtful.

They also love to travel and love getting out of their comfort zone. If you have this birthstone, you are known to make great decisions and should listen to your intuition more often.

7. July – Ruby

Ruby Ring in a BoxRuby is considered to be the king of gems, so if you’re born in July you’re pretty lucky. Those with this birthstone are known to have a zest for life, are bold and courageous as well as ambitious. Their confident nature makes them great leaders. They give off energy and can charm anyone around them.

8. August – Peridot

This stone is vibrant in color and radiates positive energy. August borns are known to be extra loving and thoughtful. They give off a warm and welcoming aura that attracts people to them, whether strangers or friends. They are bold and not afraid to be who they are. August borns are extroverts and can get anyone to trust them due to their friendly vibe.

9. September – Sapphire

This precious mineral comes in a variety of colors, but is most famous for its blue color. People with this stone are considered to be calm and slightly introverted, only opening up to people they are close to. It takes them time to build trust with someone, but when they do, it is usually life-long. They are wise and think carefully before they speak.

10. October – Pink Tourmaline

Tourmaline minerals in a boxThis exotic gem comes in the most delicious hues of pinks. Over the years, it has been known to possess many healing powers. Those who have this birthstone are considered to be lively and passionate. They are also known to have a great intuitive sense. Although they seem calm on the outside, don’t be fooled! These October borns are restless and have an urge to explore the world. Their minds are the opposite of calm and are always thinking about what’s next.

11. November – Topaz

Those with this birthstone are considered to be extremely lucky. They are known to have it all, whether it’s finances, travel, career, etc. This birthstone holder has an important role to play in the lives of the people around them. Not only are they the life of the party but also the glue that holds their family together. They give off positive energy and therefore attract that in return.

12. December – Blue Topaz

This one of a kind stone is known for its breathtaking shades of blues. Those born in this month are considered to be old souls and wise beyond their years. They are famous for being friendly and can get along with practically anyone around them. December borns attract love and are loving and caring themselves. They are creative and make great lovers. 


Howard Fensterman Minerals