photographic essay on a fluid motion and or a particle phenomena in working or living world. no more...

Question

photographic essay on a fluid motion and or a particle phenomena in working or living world. no more than 5 pages or 1000 word. the photo-essay's should be vey creative and visually appealing. the project marks are concentrated on aesthetics. provided examples of how should it look like. the photographic part is very importantBrewing the perfect   offee is a ritual for many: enjoyed first thing, for a  lunchtime catch up, or as a boost to finish that  report due tomorrow morning.   Coffee consumption has been on the rise in Australia.  With the proliferation of speciality coffee, whole bean  sales have doubled in the last 8 years [1].   Achieving the perfect cup of coffee is not a simple task.  There are many factors affecting the final cup: roast  profile (dark/light), brewing temperature, time, and the  amount coffee and water used, to name a few.  However, one of the most fundamental is the grind size.  Ever wondered why your espresso machine pours  the perfect shot one day, and then the next  the water won’t come through, despite  the fact you haven’t changed a thing?  We’ll walk you through the basics  of particle size distribution. Grinding  You could just put whole beans in  water, though you wouldn’t extract  much; Before brewing, you must first  grind them.  The purpose of grinding coffee is to  increase the total surface area from  which to extract, since molecules are  first dissolved from the surface of coffee  particles. C  Particle size distribution  When ground, coffee beans are  split into smaller particles. The  catch is: they don’t split evenly.  Some particles will be larger and  some very fine. A distribution  typically ranges from 10-1000 μm  in particle diameter [2, 3],  depending on how you set your  grinder.  In the graph to the side, you can  see the distributions formed by  grinding coffee through 3 different  grinders on espresso setting (quite  fine). [Figure 2 shows the surface  area contribution of each particle  size. For example, the sum of all  the particles with a diameter of 50  μm contribute 10% of the total  surface area.  Surface area  The greater number of particles  we create, the smaller each of  their diameters are, and thus the  greater surface area we obtain from  the same volume.  The smaller the particle diameter, the higher the surface area to volume ratio, and thus the  more extraction [3, 4].  A good way to understand why this is true,  is to imagine cutting a lemon in half. You  still have the same volume of lemon, but  now you have all the surface area you  had before plus two extra circles.  In the same way, the finer you grind your  coffee, the greater the total surface area  becomes while the total volume stays  the same. [Figure 2]: Particle Surface Area vs Particle Diamerter [Figure 1]: Ground coffee particle under an electron microscope  Variables affecting particle distribution  The three main things that will affect your grind are temperature, moisture [2] and of  course grind setting (distance between grinder burrs).  Moisture is determined by the roast profile (darker: less moisture, lighter: more moisture),  days since the roast date and how you store you beans. The temperature is determined by  the ambient temperature, the latent heat in the burrs from previous grinding, and the  friction from grinding.  This is why your espresso machine pours perfectly one day, and then the next the  water won’t come through. The beans are colder than  when you ground your coffee last and have  produced overall smaller particles than before  [2], causing more resistance to the water  passing through, leaving you  frustrated and confused. Putting it all into practice  Ok, now that we understand what a particle size distribution is and what changes it, how  does this help us brew a delicious cup of caffeinated bean water? We can control 3 things  that affect the grind size: temperature, moisture and grind setting. Grind setting will have  by far the largest effect.  Storage (moisture control):  The easiest way to store your beans is at room temperature in a resealable container with  a one-way valve. The valve serves to release CO2 that is produced during the roasting  process and is still escaping from the freshly roasted beans. The container should be air- tight, to prevent your beans from absorbing moisture from the atmosphere, as roasted  coffee beans are highly absorbent [5]. When not grinding in volume, it’s best to weigh out  the coffee you need to grind and keep the rest stored in an air-tight container.  Temperature:  Temperature is a bit harder to control. You could keep beans in the fridge/freezer, as it’s  been shown that lower temperatures produce a tighter distribution [2] (smaller range of  particle sizes), but you then run the risk of exposing your beans to moisture.  The easiest way to store your beans is in a cupboard. Depending how you heat/cool your  home your cupboards should remain at a fairly constant temperature.  Grind Setting  The distance between your burrs is the single largest determining factor in changing your  particle distribution. When you increase your grind setting, your distribution will shift on  average to larger particle diameters, and smaller diameters when decreasing grind setting.  Though, unfortunately, the shift will not be uniform. Often increasing the grind setting,  while producing larger particles on average, will also produce more fines (the smallest  particles

Arnab Kanti · Accepted Answer

WPS Presentation
Liquids & gases are collectively called fluids. Fluids move under the influence of pressure & gravity. Fluid motion is of three types, laminar, transient & turbulent which depends on the velocity of the fluid particles in motion, external pressure & geometric variations in the transport medium such as change in the diameter of the pipe. Interestingly, fluid motion can be altered by external means and used for several applications in day to day life.  A British scientist named Osborne Reynolds discovered a phenomenon in the year 1883 that the transition of nature of flow of a fluid in a medium such as pipe depends on a factor which is equal to the density of the fluid multiplied by the velocity of the fluid and diameter of the material in which the fluid is flowing and then divided by the dynamic viscosity of the fluid. The factor was named as Reynold’s number which is the ratio of inertia forces to the vicous forces acting on the fluid. This number is still used in almost all applications of fluid flow. Laminar flows have low Reynold’s number whereas turbulent flows are associated with high Reynold’s number. The range of values depend on the condition of flow. For open flow conditions, laminar flows are associated with Reynold’s number less than 500 & turbulent flows show more than 1000. Whereas for closed pipe under full-flow condition, laminar & turbulent flows have Reynold’s number of less than 2000 & more than 4000 respectively. 
Fluid flow : an interesting topic 
Transient state of flow occurs when laminar flow starts to break. Transient nature of flow either turns to laminar or turbulent and do not exist for a long time. This phenomenon can be easily observed bylooking at a burning incense stick. The smoke near the tip of the burning stick is laminar upto a part after which transient smoke is seen which ultimately turns turbulent in nature.

Brewing the perfect offee is a ritual for many: enjoyed first thing, for a lunchtime catch up, or as a boost to finish that report due tomorrow morning. Coffee consumption has been on the rise in...

Answer To: Brewing the perfect offee is a ritual for many: enjoyed first thing, for a lunchtime catch up, or as...

Answer To This Question Is Available To Download

Related Questions & Answers

Submit New Assignment