Mechanism (engineering)

Mechanism (engineering)

Mechanism (engineering)

09/21/17

“How can we use force and rotation to deal with complex situations?”

 

One of the principal ideas in engineering is transferring force and rotation to perform useful activities. However, simple machines are often not enough to deal with the complex and varied nature of high-level problems. So how can we use our engineering mindsets to solve this? Well, what if we were to make our machines to be assembled of a complex assemblage of parts such as gears, belts, linkages, and chain drives? This framework is known as a mechanism and is the basis for many modern day machines such as drivetrains, internal combustion engines, and aircraft landing gears.

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Zone of saturation

Zone of saturation

Zone of saturation

09/20/17

“What is the area underground where the pores and cracks are filled with water?”

 

Aquifers are natural underground water storage tanks. So naturally, if there are open areas nearby some of the water might seep out. This water usually ends up filling the pores of a region known as the Zone of Saturation, also known as the Phreatic Zone. Zones of alienation worldwide are being polluted by unsustainable practices and depleted by global warming

Underfloor Air Distribution Systems

Underfloor Air Distribution Systems

Underfloor Air Distribution Systems

09/19/2017

“How can we optimize HVAC systems by completely reinventing them?”

 

Most HVAC systems operate by using ceiling-based air vents. However, the air funneled can suffer from low quality, induce low comfort, and most importantly give a high energy bill! So how can we use our engineering mindset to fix these problems? Well, what if we were to completely reinvent the paradigm, and instead funnel air directly from the ground? It turns out that this is the exact idea behind a technology known as Underfloor Air Distribution Systems. These systems work by filtering air through the open space between the structural concrete slabs on the floor of a building using plenums for direct cooling. Underfloor Air Distribution Systems are commonly implemented in data centers for their high efficiency and low cost.

Pulse-width Modulation

Pulse-width Modulation

Pulse-width Modulation

09/18/17

“How can we use a digital signal to control power appliances?”

Using sinusoidal analog signals for control applications has drawbacks. Specifically, the constantly changing signal can cause the resistors on a circuit to heat up and induce damage. However, how can we use our engineering mindset to fix this problem? Well, what if we were to replace this analog system with a discrete one operating at a duty cycle? That way we can imitate the perpetually switching signal while avoiding the issues that come along with it. This type of signaling is known as pulse-width modulation and is one of the fundamental ideas of modern control theory

 

The Strange Second State of Water

The Strange Second State of Water

 

The Strange Second State of Water

09/17/17

“Can water have a second liquid state?”

 

Water is a most peculiar molecular compound. Although this material composes over sixty percent of the human body and the vast majority of the Earth’s surface area, we still know very little about the chemical and physical properties and behaviors of this element. And this idea could not be better exemplified by a most recent discovery lead by a highly intelligent group of scientists.

At Oxford University, A group of physicists led by the postdoctoral research assistant Laura Martinez Maestro had decided to conduct a new experiment on water (Crew, Bec). For this, they took a sample of water at zero degrees Celsius and increased the temperature slowly until it reached one hundred degrees Celsius while measuring the thermal conductivity, refractive index, conductivity, surface tension, and the dielectric constant. Once the water hit, 40 degrees Celsius, its properties started to shift drastically, and once it had hit 60 degrees Celsius all of its properties had changed into something new. Specifically, the temperature of change was 64 degrees Celsius for thermal conductivity, 50 degrees Celsius for refractive index, about 53 degrees Celsius for conductivity, and 57 degrees Celsius for surface tension.

Why does this happen? Although everything seems murky at the moment, this phenomenon might be a consequence of the fact that water molecules only have a very weak bond with one another, and that the bond between oxygen and hydrogen is far greater than the hydrogen-hydrogen bonding. As a result, the molecular structure of  molecules is constantly changing and reforming, leading many to believe that this might be the cause for the strange second stage of matter

 

References

Crew, Bec. “Physicists Just Discovered a Second State of Liquid Water.” ScienceAlert, ScienceAlert, 14 Nov. 2016, http://www.sciencealert.com/physicists-just-discovered-a-second-state-of-liquid-water.

On water’s expansion with freezing

On water’s expansion with freezing

On water’s expansion with freezing

09/16/17

“Why does water expand upon freezing?”

The variation of volume with thermal energy for most liquids has a very simple characteristic. When heat is applied, the volume increases, and vice versa for cooling. This is because the added (or subtracted) energy will cause the amplitude of the vibrations of the molecules to change, thereby modifying the volume. For example, when a liquid freezes, the molecules will pack into one another, thereby shrinking the volume.

However, water exhibits a very peculiar phenomenon. When water is cooled to its freezing point, its volume will actually expand. Why does this happen? Well, let’s analyze it using our scientific mindset. Unlike most other molecules, water has a very unusual structure. Specifically, a water molecule’s primary form of bonding is based on hydrogen bonding. When temperature decreases, the strength of a hydrogen bond actually increases (since the lower thermal energy means that the hydrogen bonds will have less vibrational energy, therefore lowering the chance to shake out of position and increasing stability).

Once water is cooled into ice, the only bonding will be hydrogen bonding. Specifically, it will be bonded in a hexagonal structure, which is a much more “open” network than most structures. The tandem of hydrogen bonding and a hexagonal structure vastly decreasing the density (Levine, Scott 2013). And because density is described by the equation, with being the density,  being the mass, and being the volume, and as mass is constant, when the density decreases the volume must increase as a result. Consequentially, the volume of water increases upon freezing! This fact has multiple implications. For example, a lower density of ice means that ice will float in water, which allows for complex structures such as ice glaciers to occur naturally.

 

References

“Why Does Water Expand When It Freezes? .” FAQ: Water Expansion on Freezing, New York University, 3 Dec. 2013, http://www.iapws.org/faq1/freeze.html.

Smart Zoning for HVAC Systems

Smart Zoning for HVAC Systems

Smart Zoning for HVAC Systems

09/15/17

“Can we solve the problem of temperature discrepancy in buildings?”

 

When we think of buildings, many of us assume that the temperature inside will be completely uniform in nature. However, more often there is significant temperature variation from room to room. Making this worse, most HVAC systems only base their setpoints on one of these rooms, causing improper heating and discomfort in the rest of the building. So how can we solve this problem using our engineering mindset? Well, what if we were to use multiple smart thermostats to divide the building into multiple zones, each with their own setpoints? This is the fundamental idea behind smart zoning for HVAC systems, nascent but intriguing technology which has the promise to vastly improve the ergonomic, economic, and ecological capacity of everyday heating and cooling.