The Joys of a Local University

They say the cream of the crop enters local universities, yet while most of our friends at school have already graduated from foreign universities or have already started working we, the undergraduates of the local universities have barely completed halfway through the BSc Engineering degree. However local universities provide some experiences that can never be found anywhere else.

To start with, the never-ending strikes. To us, the word "Strike" is synonymous with Holiday, but there is a slight difference, when holidays are given you know exactly when university will reopen but in a strike you will never know. Strikes in universities first brings joy because it means an extended vacation, then it builds anticipation. Boredom sets up when you get fed up of staying at home and finally regret kicks in when you realize you have to wait longer to complete the degree.

Somehow after all the strikes are over and university reopens after a long break the real fun begins.. Semester Exams without reading weeks! It's as if we are being punished for staff union actions. Lectures fill all the slots in the time table and the semester progresses in full throttle ending up with the exam and starting the next semester on the very next day. This happens until another strike comes up and the cycle starts over again..

Each semester in our degree programme is marked with one specific hardship, my buddies in the department know what I'm talking about, first semester - fresher pressure. Second semester - hand written coursework. Third semester - 64 hours of manual engineering drawing, and future semesters only god knows what..But it has been fun, and it gives us something to associate with each stage of our university life.

These are some of the experiences that can only be found at a local university. It might take a little longer to get our degree, but its worth it. someday when we look back at our university life these will be sweet memories. To my friends who are reading this post right now, let's not worry too much about the strike. Let's make the maximum out of the time we spend at campus. We must consider ourselves lucky because not everyone got the opportunity that we got..

Sand Mining and Storm Damage

Beach sand mining has increased during the past few decades as river sand has gradually depleted causing several environmental problems. Beach/sea sand is not suitable for construction purpose as a replacement for river sand due to its salinity. The salinity in the sea sand can corrode steel reinforcements and cause structural failures if used in concrete. However the sea sand can be thoroughly washed to remove its salinity before using it for construction purposes. Due to this reason beach sand is mined increasingly in order to avert the environmental damage caused by mining river sand.
This is not a good solution because beach sand mining has its own harmful side effects. While most will agree that offshore mining is not very environmental friendly few realize that beach sand mining is as catastrophic. The sand on the beach and in the sea belong to one dynamic system. Removing sand from the beach therefore will disturb this balance.

image from http://www.seafriends.org.nz/oceano/beach.htm

This is what a typical healthy beach looks like. Even the sand far away from the water are part of the beach. The dunes on a beach serve a purpose.

image from http://www.seafriends.org.nz/oceano/beach.htm

The above picture depicts the behaviour of the sand during a storm. Note how sand is borrowed from the fore dunes to create a bank below the sea level. This bank helps to break the waves and dissipate energy thus minimizing the damage caused by the storm.
So what would happen if the sand is carelessly removed from the beach? There wouldn't be a way for the beach to adapt during a storm. This will lead to severe inundation and damage.
The sand in a healthy beach undergoes a cycle known as the "beach cycle". The beach continuously adapts by moving sand and sediments and rebuilds itself after storm damage by itself. Removing sand from the beach could disturb this cycle and cause long term effects such as severe coastal erosion. This makes it necessary to explore alternative methods to mine sand. Deep sea sand mining, carried out far away from the coast could be a possible solution although its effects and impacts should be thoroughly assessed first.

Earth's Structure

In a previous post of mine named Onion Earth I explained how the earth has a layered structure somewhat resembling an onion. The earth has several layers such as crust, mantle core, asthenosphere, mesosphere etc. Some of these layers overlap each other and thus can create confusion. This problem could be avoided by classifying these layers in two ways, one based on the Chemical composition and the other based on the physical properties.

Based on Chemical composition, three layers are identified.
1. Crust  -  Abundant in elements Si , O, Al, Mg, and Fe
2. Mantle  -  Mainly Fe, Mg, Si
3. Core  -  Ni and Fe alloy

Based on the physical properties five layers are identified.
1. Lithosphere  -  Rigid outer shell. Comprises of the crust and uppermost mantle
2. Asthenoshpere  -  Shows plastic behavior. Lithosphere "floats" on this layer. 5% of rocks in this layer is molten
3. Mesosphere  -  Extends from about 300km to 2000km beneath the surface. Solid
4. Outer Core  -  Molten. Rotates around the inner core and produces the earths magnetic field
5. Inner Core  -  Extreme pressure causes it to stay solid despite the high temperatures

Source : http://www.tulane.edu/~sanelson/images/earthint.gif

A Classification of Ocean Waves

The sight of waves breaking at a shore is common sight to most of us. While it is relaxing to watch the constant pounding of the waves while listening to the hum of the sea, we don't give much thought to the way these waves are formed or the types of waves in the ocean.
Ocean waves are classified into seven major groups depending on their size, period and way of formation. These types are described below.

1. Capillary Waves
Capillary waves are the smallest of these types, having a period generally less than 0.1sec and a wavelength less than a couple of centimeters. Capillary waves are caused by local winds, more specifically short bursts of winds. Capillary waves are similar to ripples created on a body of water by dropping an object into it. The restoring force in the case of capillary waves is surface tension

2. Chop waves
These are the the common waves in the ocean familiar to everyone. These waves have periods of several seconds, and wavelengths ranging from 1 to 10 metres. Chops are wind generated waves. A consistent blowing of find over a considerable fetch(sea surface area over which the wind blows) causes these waves. The restoring force of these waves is gravity.

3. Swells
Swells are much larger wind generated waves. Very powerful winds are required for the creation of these waves and they are related to distant storm surges. Periods can vary between 10 and 30 seconds and wavelengths are in the order of hundreds of metres. Swells occurring alongside a storm in coastal ares can have devastating effects.

4. Seiches
Seiches are standing waves that can be created by wind, seismic disturbances or by tidal resonance. The word seiche originates in a Swiss French dialect word that means "to sway back and forth". This an accurate description of the wave because it actually sways to and fro like a see-saw. These waves can be generated at harbours, estuaries, lagoons and even swimming pools. You can visualize a seiche by giving a nudge to your tea cup. The resulting oscillatory motion of the liquid in the cup is similar to that of a seiche. Seiches can have periods ranging from a couple of minutes to several hours and wavelengths upto hundreds of kilometres.

5. Tsunamis
Tsunamis are massive and catastrophic waves generated by submarine disturbances. Two major tsunamis have occurred during the past decade causing severe destruction to places affected. The most common submarine activity leading to tsunamis is subduction between tectonic plates. However other disturbances such as landslides could also produce tsunamis. Tsunamis can have a period of about an hour and wavelength can reach hundreds of kilometres.

6. Tides
Tides that are caused by the gravitational attraction of the sun and moon are familiar to us but few realize that it is classified as a wave. Tides have periods of 12.8 or 24.8 hours and are related to the earths speed of rotation. Wavelengths are in the order of thousands of kilometres.

Seniority Complex

Some of the seniors in university have the "Seniority Complex". For no apparent reason they love to shout at the juniors and and make them feel uncomfortable. While seniors are usually expected to set an example and guide the younger ones, these seniors do quite the opposite. They address the juniors in harsh words and they keep reminding the juniors that they are senior and that the "seniority" should be respected, while not even pronouncing the word "seniority" properly! In my opinion, respect should be earned, not demanded like this. The reason for this odd behavior could be that they wan't to cover up their own incompetence. These seniors have the personality of an earthworm and are good for nothing and therefore the false pride and authority derived from shouting at the juniors might be what they are after. they also seem to have forgotten that they too were juniors before. This is a serious problem and if not taken care of, it can be a factor in the degradation of this educational entity.

The unseen side of Graphite mining

Graphite is a major export of Sri Lanka and is mined at two places in the country namely, Kahatagaha and Bogala. Sri Lanka is the only country in the world where crystalline graphite or lump(vein) graphite is mined underground. The graphite such mined is also of very high quality and is very pure-99%pure C.

Graphite -image from Wikipedia

In a very brief report I wrote about the graphite mining practices in Sri Lanka, based on an investigation carried out at the Graphite mine in Kahataga, I concluded that no overall damage to the environment was done. This was because graphite being a natural product and is essentially pure carbon which is not a toxic substance, it cannot do any harm to the environment. However further research and more thought put into the matter shows that I couldn't have been more further from the truth. Graphite mining, just like any other mining has a considerable impact on the environment and can lead to catastrophic result if preventive measures are not implemented.

Mining graphite involves the use of explosives to crack open the rock joints and to expose the graphite. The amount of explosives used in this process is often more than what actually is required and therefore ends up creating damage to unintended areas as well. this process also result in the release of dust and very fine particles of Carbon into the atmosphere causing air pollution. This can lead to the deterioration of   the health of workers and people living in the vicinity.

Mining graphite is followed by the processing at the site itself. This processing of Graphite also has a negative impact on the environment of its own. In addition to releasing a larger amount of fine graphite particles into the atmosphere the graphite powder spillages can cause soil contamination and cause harmful effects to flora and fauna.

The underground mining process has a separate set of impacts. The emptying of fissures in the rock and the separation of rock joints can cause water to seep through them and eventually lead to landslides that can destroy the whole area. Furthermore the structure of the dug mine can result in the alteration of water tables causing a heap of environmental impacts. Disturbing the natural water cycle and introducing contaminants can cause damage to both nature and humans. 

To avoid or minimize these harmful impacts, the mining will have to be done after thorough planning with thought given to the environment as well as economic benefits. After mining the land will have to restored to its previous state to bring back the balance. Care should be taken regarding the the chemicals and explosives used in the process and also the wastes generated and discharged. By adopting these practices and through implantation of concepts like cleaner production Graphite mining can be made more environmentally friendly.

Volcanic Glass

There are three types of rocks on earth. They are Igneous, Sedimentary and Metamorphic rocks. Igneous rocks are formed by the solidification of magma and are further divided into two types, Namely, Plutonic rocks(Intrusive igneous rocks) and Volcanic rocks(Extrusive igneous rocks). Plutonic rocks are the rocks that are solidified inside the earth and are usually crystalline in nature due to the slow cooling process Thus they have a coarse grained crystal structure. Volcanic rocks however solidify muck quicker and therefore often show a very fine grained crystal structure. If the cooling and solidification of the volcanic rocks happen even faster it leaves no time for crystal formation. This makes the volcanic rocks amorphous and therefore have properties of a supercooled liquid. That is, These rocks have a glassy texture and are brittle like glass. They also exhibit a conchoidal fracture just like glass. One such rock is Obsidian. Obisidian looks almost artificial and has a remarkable appearance. They are sometimes used to fashion precision cutting tools such as surgical knives. Obsidian has such an appearance that it is hard to believe that it actually is a rock and that it is formed naturally.. It looks artificial. It is a remarkable product of Earth's natural geology. Here's a picture of Obsidian.

XRF

This post is about X Ray Fluorescence Spectroscopy. If the Name sounds too complicating or sounds uninteresting feel free to ignore this post. Stephen Hawking says in the preface to his book-"The Universe in a Nutshell", that his publisher advised him saying that the inclusion of an equation or technical details will cut down his readership by half. So he didn't do it. But I'm going to write about X Ray Fluorescence Spectroscopy in this blog, and I don't care about the readership. Besides, at the moment I'm writing this post, I don't have any readers! I 'm writing this as a way of remembering what I learned in preparing a presentation on XRF under the module Analytical Methods.
Back to the topic. When high energy electromagnetic radiation-usually in the form of X Rays, strikes a material, The atoms in the material may get ionized. If the energy is sufficient, an atom can lose an electron from one of its lower orbitals. This causes an instability in the atom and therefore an electron from a higher orbital fills in the gap created by the dismissed electron. This causes a release of energy again in the form of X rays but with lower energy than the primary, incident X rays. These secondary X rays are called Fluorescent X rays, and the phenomenon is named Fluorescence.
This released energy corresponds to the energy difference between the orbitals involved and is unique to the atoms of a particular element. This makes it possible, to identify the elements present in a sample by analyzing its fluorescent X rays. In fact, analyzing here means measuring the energy of the emitted radiation. This method of analysis is called X Ray Fluorescence Spectroscopy.
The XRF Spectrometer consists of the primary X ray Source, the sample, the detector and the computer. XRF Spectrometers are further classified into two types;
1. Energy Dispersive Spectrometers(EDS/EDX)
2. Wavelength Dispersive Spectrometers(WDS/WDX)
In the energy Dispersive type the fluorescent X rays are directly measured and is the faster and cheaper method. The Wavelength dispersive type uses an analyzer crystal to separate the different wavelengths before they are focused into the detector. This method the more sensitive method.
A variety of elements can be identified using XRF Spectroscopy and it is commonly used in Geo Chemical investigations and mineral analysis. Recent developments to this technique and emergence of handheld XRF Spectrometers has brought about its application in fields like forensics and archaeology as well. XRF Spectroscopy was recently used to analyze the painting techniques used by Leonardo Da Vinci in creating his world famous masterpiece-"Mona Lisa".

Sky Observation at the Arthur C. Clarke Institute

After the first semester examination in our University, We were supposed to study 3 non technical modules-two of  which were compulsory and one of our own choice. The module I chose was Astronomy. The reasons for my choice were the interest I had in Astronomy, The interesting course contents and most importantly, The observation sessions.

We had two observation sessions at the Arthur C. Clarke Institute. One in the night for the observation of the Moon and the Planets and one session in the morning for observation of the Sun.
The telescope at the Arthur C. Clarke Institute, is the largest telescope in Sri Lanka. It is a Cassegrain Reflector type telescope and has a primary mirror of diameter 45cm. It uses an Equatorial Mount and is moved using computer controlled servo motors. It uses CCD cameras as the main imaging device.

It was unfortunate that the on the night we had our moon observation, the sky was very cloudy and not a single star could be seen. Also it was lightning. Because of this we couldn't use the Cassegrain reflector that night. Instead we used a much smaller reflector to look at the moon. The image of the moon was not clear due to the obstructing clouds.

The following day was better. We viewed the sun through the filtered Cassegrain telescope and saw two Sunspots. We also saw the Chromosphere of the Sun through an H-alpha filter.

The two sessions at the institute were very interesting and educational. It was a truly memorable experience.