Month: September 2017

Liquid pressure variation with height

Liquid pressure variation with height

Liquid pressure variation with height

09/12/17

“How does the pressure of a liquid vary with height?”

 

Liquids are famous for their permeable structure, such that you can insert an object at any point inside it. However, depending on which part of the height you insert it, it will experience a different pressure. So how can we quantify this pressure variation with height? Well, if we investigate empirically, we will find out that this variation can be symbolically represented as P = rho*g*h, with P being the pressure, rho being the density, g being the gravitational acceleration, and h being the height.

Plenum chambers

Plenum chambers

Plenum chambers

09/11/17

“How can we store gas for heating?”

 

Oftentimes, we need to store gas to heat a space. So how can we do this using our engineering mindset? Well, what if we were to simply have a pressurized house that could trap a gas and release it on command? This is the basic idea behind a plenum chamber and is used in houses all over the world.

Quadratic programming

Quadratic programming

Quadratic programming

09/10/17

“How can we optimize a nonlinear phenomenon using math?”

 

Linear programming is great for optimizing first order models. However, most real world systems are actually nonlinear in nature and thus require something further than linear programming. So how can we devise a method new, more optimal method? Well, let’s think about it. First, let’s boil everything down into matrices. Then, let’s introduce their constraints. The equation should now be in the form f(x) = 0.5*x^T*B*x – x^T*b subject to A1*x = c and A2*x = d, where x is the set of all independent variables, B and b are any quadratic objective function on these variables, and A1/c and A2/d are the inequality and equality constraints. Once we have the system set up, we can enter it into a computational package and achieve our results. This method is known as quadratic programming and is frequently used to solve problems fields ranging from energy analysis to finance

Diffuser (thermodynamics)

Diffuser (thermodynamics)

Diffuser (thermodynamics)

09/08/17

“How can we slow down a fluid while increasing its pressure?”

 

When working with fluids, we often want to modify its properties in some meaningful way. This could include changing more than one at once, such as slowing down its velocity while increasing its pressure. So how exactly can we accomplish this? Well, what if we were to just get a machine to do this? This is the exact idea behind a diffuser, which is the basis of operation for multiple types of HVAC systems.

Climate change and the receding of Arctic sea ice

Climate change and the receding of Arctic sea ice

Climate change and the receding of Arctic sea ice

09/08/17

“How is climate change affecting the Arctic sea ice?”

 

Let’s think about something for a moment. We know that ice is more likely to melt when it is immersed in higher temperatures. And we know that the northernmost pole of the Earth (the arctic) is composed mainly of ice, and that climate change is causing global temperatures to rise. So wouldn’t it be logical that such a phenomena would be causing the arctic sea ice to recede? Well, it turns out that according to empirical evidence this is exactly what is happening, as ever since we have started taking satellite measurements of the polar ice caps in 1979 we have seen a 35% decrease in landmass!

How we can infer climate change from the ocean

How we can infer climate change from the ocean

How we can infer climate change from the ocean

09/07/17

“Can we learn about climate change just by looking at ocean data?”

 

Climate change is something that is talked about every day. However, how can we get some evidence for it? Well, what if we were to look at the temperature of the most massive body of heat storage on the Earth, the ocean! By carefully observing its temperatures, we can observe that the ocean has gained 0.1-degree Celsius since 1969^1. Even though this does not seem like a significant deviation, we must remember that our global ocean is composed of around 1.4 * 10^24 worth of water (a substance with a substantial heat capacity), so any temperature change even an order of magnitude close to our observed value is quite drastic. 

 

  1. Levitus, et al, “Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems,” Geophys. Res. Lett. 36, L07608 (2009).

 

Thermostatically Controlled Loads

Thermostatically Controlled Loads

Thermostatically Controlled Loads

09/06/17

“How exactly can we model loads that are controlled by thermostats?”

 

Machines take energy from the grid under many parameters. And some of them are controlled by environmental temperatures, such as temperature. And a portion of these units (such as HVAC systems, water boilers, and refrigerators) try to match their setpoints to a value on a thermostat. These machines are known as thermostatically controlled loads and are used in grid-building system modeling to generate predictions about demand side energy usage.

Deadband

Deadband

Deadband

09/05/17

“Do some control systems have a zone with no feedback?”
Ideal controls systems are available to take in all possible frequencies. Some controls systems have a zone where the input frequency will return nothing. This region is known as the deadband and can be used to prevent unwanted side-effects.

How to solve farsightedness using physics

How to solve farsightedness using physics

How to solve farsightedness using physics

09/04/17

“How can we correct farsightedness using scientific knowledge?”

 

Although not as pervasive as near-sightedness, far sightedness is becoming an increasingly common problem, with 5-10 percent of Americans experiencing such a diagnosis. Nearsightedness, also known as hyperopia, is caused when the focal length of an individual’s eyeball is too large, causing the incoming light rays to focus on a point behind the eye (Make a link to how images form in the eye), which in turn will cause a fuzzy image. To correct this, we can insert a positive lens in front of the eye of an individual, which will cause the light to refocus at the back of the eye, enabling normal sight.